Aesthetics and Functionality in Ear Reconstruction (Advances in Oto-Rhino-Laryngology, Vol. 68)

Aesthetics and Functionality in Ear Reconstruction

Advances in Oto-Rhino-Laryngology Vol. 68

Series Editor

W. Arnold

Munich

Aesthetics and Functionality in Ear Reconstruction Volume Editor

Rainer Staudenmaier

Munich

117 figures, 9 in color, and 5 tables, 2010

Basel · Freiburg · Paris · London · New York · Bangalore · Bangkok · Shanghai · Singapore · Tokyo · Sydney

Rainer Staudenmaier Hals-Nasen-Ohrenklinik der Technischen Universität München Klinikum rechts der Isar Ismaninger Strasse 22 DE–81675 Munich (Germany)

For Lena, Julius and Carl.

Library of Congress Cataloging-in-Publication Data Aesthetics and functionality in ear reconstruction / volume editor, Rainer Staudenmaier. p. ; cm. -- (Advances in oto-rhino-laryngology, ISSN 0065-3071 ; v. 68) Includes bibliographical references and indexes. ISBN 978-3-8055-9316-8 (hard cover : alk. paper) 1. Otoplasty. I. Staudenmaier, Rainer. II. Series: Advances in oto-rhino-laryngology, v. 68. 0065-3071 ; [DNLM: 1. Ear Auricle--abnormalities. 2. Ear Auricle--surgery. 3. Ear Auricle--physiology. 4. Reconstructive Surgical Procedures--methods. W1 AD701 v.68 2010 / WV 220 A254 2010] RF127.A47 2010 617.8⬘059--dc22 2010001238

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Section Title

Contents

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1 25 53

65 81 95 108 120

132 133

Preface Staudenmaier, R. (Munich) History of Auricular Reconstruction Weerda, H. (Lübeck) State-of-the-Art Autogenous Ear Reconstruction in Cases of Microtia Firmin, F. (Paris) Ear Reconstruction with Porous Polyethylene Implants Berghaus, A.; Stelter, K. (Munich); Naumann, A. (Homburg/Saar); Hempel, J.M. (Munich) Auricular Prostheses Federspil, P.A. (Heidelberg) Combined Aesthetic and Functional Reconstruction of Ear Malformations Kiefer, J. (Regensburg); Staudenmaier, R. (Munich) Combined Reconstruction of Congenital Auricular Atresia and Severe Microtia Siegert, R. (Recklinghausen) Ear Reconstruction through Tissue Engineering Haisch, A. (Berlin) Customized Tissue Engineering For Ear Reconstruction Staudenmaier, R. (Munich); Hoang, N.T. (Munich/Hanoi); Mandlik, V.; Schurr, C.; Burghartz, M.; Hauber, K. (Munich); Meier, G. (Kaufbeuren); Kadegge, G. (Gauting); Blunk, T. (Regensburg) Author Index Subject Index

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Preface

The reconstruction of the auricle, due to dysplasia or sub/total auricle amputation, was seldom described before the beginning of the 20th century. The first techniques were described in 1845 by the famous German plastic surgeon Diefenbach, but he advised against reconstruction of total ear loss because of poor surgical results. In the early 1950s, more publications concerning the reconstruction of the external ear appeared, and it was during this period that the first modern methods for reconstructions, which use alloplastic materials or autogenous rib cartilage, were described. Over the last 25 years, these types of operations have become reliable methods that give satisfying aesthetic results. Following the sage advice of Dr. McDowell in 1977 that you have to learn what others have done because you will not live long enough to make all these mistakes by yourself, we have summarized the past developments in ear reconstruction alongside a detailed presentation of future opportunities. Hilko Weerda, one of the first German surgeons to focus on ear reconstructions, has given a historical overview of this field. In his article, the most important surgical techniques for ear reconstruction have been summarized. His excellent illustrations offer a clear impression of these techniques, including partial and total reconstructions, ear prostheses, the use of regional flaps, skin expansion and the use of autogenous rib cartilage for total reconstructions, and make it possible to apply these to the high diversity of patient problems. Francoise Firmin, one of the most experienced surgeons in external ear reconstructions in the world – who was educated by the famous Burt Brent, has described state-of-the-art treatment in autologous ear reconstruction in cases of microtia. In her work, she has focused on the natural shape of the external ear, recreating the complex 3-dimensional architecture. The quality of her work is derived from two important considerations: firstly, precise preparation of the cartilage; secondly, making appropriate choices to correctly adapt the skin remnants to the cartilaginous framework. She describes her two-step procedure, in which the first step includes the insertion of the framework under the skin, and the second step comprises the elevation of the reconstructed ear (creating the retroauricular sulcus). This article, based on her personal experience of 1,520 cases, highlights the optimization of surgical techniques,

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the avoidance of pitfalls encountered by both beginners and highly experienced surgeons, and offers many helpful hints and tips to bring about better results. My heartfelt thanks go to Hilko Weerda and Francoise Firmin for sharing their personal experience and knowledge of this complex field. Alexander Berghaus is well known for his use of alloplastic materials in the mechanical supports used for ear reconstruction. Over the last 15 years, he has focused upon porous polyethylene implants in particular. The big advantage of these techniques is the lack of donor site morbidity caused by the use of autogenous rib cartilage. He uses a 1-step procedure with porous polyethylene as the frame material, which is covered by the temporoparietal flap and a full-thickness skin graft. Using this technique, he has been able to achieve very convincing results over recent years. An alternative method for restoring the external appearance of patients with ear malformation, the use of auricle prostheses, is described by Philipp Federspil. The breakthrough in auricle prostheses came with the introduction of modern silicones (which among other advantages can be made to have suitable coloring) and the more stable fixations resulting from bone anchoring. Since then, different solitary titanium implants have been introduced to attach the prostheses, with the focus on secure retention even in unfavorable anatomical conditions. The big advantages of prostheses are the suitability for elderly people, predictable cosmetic results, fast rehabilitation, no donor site morbidity and early detection of tumor recurrence. Depending on the individual case, this could be an alternative to plastic reconstructive surgery in ear malformation. Classic microtia is combined with atresia of the external ear canal as well as considerable dysplasia of the middle ear, resulting in a functional impairment with a conductive hearing loss of around 50–60 dB. This reduced hearing ability is very important for the otorhinolaryngologist, particularly in patients with bilateral microtia. Ralf Siegert established a technique of combined reconstruction of congenital auricle atresia and severe microtia. This 3-step procedure starts with the explantation of autogenous cartilage, the shaping of the auricle framework and implantation. In addition, the tympanic membrane and the external ear canal are prefabricated, and stored in a subcutaneous pocket. The second step includes elevation of the new cartilage framework in combination with the reconstruction of the ear canal by using the prefabricated tympanic membrane and external ear canal. In the third step, the cavum concha is deepened, and the external ear canal is opened and covered with a skin graft. Being an excellent surgeon, he achieved a final conductive hearing loss of 30 dB or less in more than 76% of his patients. Because of the complex reconstruction of the external ear canal, he observed no restenosis. This combination of plastic surgery of the auricle and functional surgery of the middle ear comes more under the focus of reconstruction. Besides bone-anchored hearing aids, newly developed active middle ear implants have been used for the treatment of sensorineural hearing loss in the last 8 years. They provide acoustic amplification and transmission of sound energy by direct coupling of vibratory elements to the ossicular chain.

Preface

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Jan Kiefer first described the use of the Vibrant Soundbridge for bilateral microtia in the international literature. This partially implanted device seems to be the most favorable implant in cases of severe ear malformations because of the high variety of coupling possibilities of the floating mass transducer to the ossicular chain or the oval/round window niche. Based on good results seen in bilateral cases, Kiefer and I also implanted unilateral ear malformations. It is possible to obtain an air-conductive threshold of 30 dB or less in more than 90% of patients; thus, the Soundbridge provides a valuable option for functional reconstruction of the malformed ear. Future advances in this field will come from a variety of scientific disciplines. One of the leading ideas is to use tissue engineering to overcome donor site morbidity (from autogenous cartilage) and problems with the extrusion of alloplastic materials. We are looking at customized tissue engineering for ear reconstruction in our laboratory. Using computer-aided design/manufacturing systems, it seems to be quite possible to size and build individual scaffolds for autologous tissue engineering. The process starts with imaging data acquisition and 3D data processing. With the resulting STL file, it is possible to make customized scaffolds. After the isolation and amplification of cells from small biopsies, they can be used on individual scaffolds for tissue engineering of cartilage in order to produce an individually sized autologous implant. Andreas Haisch, one of the pioneers in ENT tissue engineering for ear reconstruction, has provided a short overview of his recent work and some developments in the field, as well as the problems yet to be overcome. The expectations concerning tissue engineering are very high in reconstructive surgery; however, more experimental studies need to be conducted. In this volume, several different aspects of reconstruction in severe ear malformation have been presented, with the aim of providing a complete, yet accessible, overview of the history, state-of-the-art techniques and future developments. Nowadays, many patients can get optimal aesthetic and functional solutions for ear malformations, but there is still room for improvement. R. Staudenmaier, Munich

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Preface

Staudenmaier R (ed): Aesthetics and Functionality in Ear Reconstruction. Adv Otorhinolaryngol. Basel, Karger, 2010, vol 68, pp 1–24

History of Auricular Reconstruction Hilko Weerda Department of Otorhinolaryngology and Plastic Surgery, Medical University of Lübeck, Lübeck, Germany

Abstract Although surgery for small auricular defects has been carried out since ancient times, plastic surgery became more common after the discovery of anesthetic techniques and advances in our understanding of sepsis and asepsis in the middle of the 19th century. After that time, we can find an increasing number of auricular operations in the literature. The middle of the 20th century marks the introduction of modern methods for partial or total auricular reconstructions. This historical account details the Copyright © 2010 S. Karger AG, Basel most important surgical techniques for ear reconstruction.

The restoration of the auricle, especially reconstruction of subtotal and total auricular loss, and very useful operative procedures for partial auricular surgery were seldom described before the beginning of the 20th century. In 1927, River [1] complained about the lack of operative descriptions in modern textbooks: he had reviewed 21 British and American textbooks written since World War I, but found reference to the subject of otoplasty in only 3 of these. Since the early 1950s, the number of publications and textbooks relating to auricular surgery increased very rapidly, so it is only possible to give a short overview of the historical development of reconstructive surgery for partial auricular defects and the reconstruction of subtotal and total loss of the auricle. Reconstructive plastic surgery requires an understanding of its history: ‘We have to learn what others have done because you won’t live long enough to make all the mistakes yourself ’ (F. McDowell [2]).

Reconstruction of Partial Loss of the Auricle

Ancient Sources Mutilations of parts of the ear as a consequence of war or as a punishment have been known throughout human history (fig. 1, 2).

Fig. 1. Lobule defects. Mexican stamp with a 4th century Aztec mask.

Fig. 2. Simon Peter cuts off the ear of Malchus (Naumburg 15th century).

Earlobe operations in India were already described in the Sushruta Samhita (600 BC) [2], where the lost earlobe was reconstructed with a pedicled flap of the cheek. In 1838, Zeis [3] explained that a surgeon can reconstruct the earlobe by slicing a patch of living flesh from the cheek whilst leaving one of its ends still attached; the part where the artificial earlobe is to be made should be slightly scarified, and the living flesh made to adhere to it [4, 5]. In the Roman Empire, the ears of slaves were mutilated as a form of identification [6]. The earlobes were pierced and the perforations enlarged with heavy chains and rings. Thus, Celsus (25 AD) described the reconstruction of partial auricular defects in a similar way to the Indian method [7]: Mutilations to the lips, the nose and the ears can be treated if they are small; if they are large, either they are not susceptible to treatment, or may be so deformed by it that the site from which material is harvested may quite easily become even more deformed than the region to be treated. But where the earlobes in a man for instance, have been pierced and have become offensive, it is enough to pass a red-hot needle quickly through the hole. If the hole in the earlobe is large, then the remaining bridge should be divided and the margins of the hole additionally freshened with a knife. The wound margins are then sutured.

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Fig. 3. Reconstruction of the upper (a) and lower (b) part of the auricle by Tagliacozzi 1597 [8]. These are the oldest known illustrations for partial ear reconstruction [9].

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Fig. 4. Upper arm flap by Tagliacozzi [8].

Partial Reconstructions in the 15th and 16th Centuries Such operations were also reported by Galen in the 2nd century AD, Abulcasis (950– 1013 AD) in Cordoba, Branca in Sicily and Tagliacozzi (16th century) in Bologna [8]. All of these physicians borrowed heavily from Indian sources. Antonius Branca, like his father, reconstructed noses and ears from the skin of the arm. The oldest known illustrations date back to Tagliacozzi [8] (1546–1599; fig. 3, 4), a professor of anatomy and medicine in Venice. In 1597, he described such techniques in his book De curtorum chirurgia per insitionem, in particular, partial reconstructions of the upper ear (fig. 3a) and the lower auricle (fig. 3b). Branca and Tagliacozzi reconstructed larger defects of noses, lips and ears with a flap of the arm (fig. 4).

History of Auricular Reconstruction

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Ear Prostheses The French surgeons Paré [10] (1509–1590) and Roux [11] (1894) preferred total reconstruction of the ear with prostheses (fig. 5).

Partial Ear Surgery since the 19th Century As early as 1845, the German surgeon Dieffenbach [13] described the reconstruction of the upper and lower auricle in his book Die operative Chirurgie (fig. 6) [4, 5]. He advised against the reconstruction of total ear loss due to the poor surgical results. Due to the combination of a greater understanding of sepsis and asepsis, the development of anesthesia (in the middle of the 19th century) and the wealth resulting from rapid industrialization, an increase in large plastic reconstructive operations and auricular reconstructions can be seen. In his textbook Handbuch der operativen Chirurgie, von Szymanowski [14] reported upper and lower auricular reconstruction using flaps in 1870 (fig. 7). Reconstruction with Auricular Reduction Historically, in the case of helical tumors or macrotia, various forms of wedge-shaped excisions have been used (fig. 8). We can also find a reduction in the size of the ear. Similar techniques to the one used by Di Martino [15], reported in 1856, were also reported by Cocheril [16] in 1894 and Joseph [17] in 1896 (fig. 9). An outstanding technique using advancement of the helix (‘sliding helix’ [4, 5]) was first performed by Gersuny [18] in 1903 (fig. 10). This elegant method has been modified in a large number of different ways [19–24] (fig. 11). Reconstruction without Auricular Reduction Reconstruction with Regional Flaps Parts of the auricle were covered with a bread-based, superiorly or posteriorly pedicled, retroauricular flap as described by Smith [25] in 1917 (fig. 12) and Omredanne [26] in 1931 (fig. 13). For reconstruction of partial defects, Joseph [9, 17, 27] used in 1910 a superiorly based postauricular and cervical flap (fig. 14). An anterorsuperiorly based retroauricular and postauricular incised transposition flap was used by Crikelair [29] in 1956 and Pollet [30] in 1966 (fig. 15). An inferiorly based postauricular flap was described by Gillies [32] in 1920 for reconstruction of the lower third of the auricle and the lobule (fig. 16). Full-thickness conchal (central) defects can be closed by a postauricular U-shaped advancement flap in 2 stages [4, 5, 33] (fig. 17).

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Fig. 5. Auricular prosthesis designed by Ambroise Paré in the 16th century [10].

Fig. 6. Reconstruction of the upper ear (a) and lobule (b), as described by Dieffenbach in 1845 [13].

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Fig. 7. Partial lower (a) and upper (b) ear reconstruction described in 1870 by von Szymanowski [14].

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Fig. 8. Various forms of wedge-shaped excisions for helical tumor surgery or auricular reduction (to correct macrotia). (a) DiMartino (1856), (b) Cheyene (1903), (c) Kölle (1911), (d) Day (1921), (e) Lexer (1933); [5]. History of Auricular Reconstruction

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Fig. 9. Wedge-shaped excision described by Joseph [17] in 1896. a Suggested excision. b Result.

Fig. 10. Technique used by Gersuny in 1903 [18] for defect closure by rotating the helix [4, 5]. a Full-thickness excision of the tumor and full-thickness crescent-shaped upper scapha excision. b Closure of the defects by rotating the helix.

Fig. 11. Modification by Weerda of the Gersuny [18] technique [19, 24]. a Excision of the tumor and 2-layer crescent-shaped excision in the scapha. b Closure of the wounds.

Fig. 12. Superiorly pedicled broad-based retroauricular flap for partial auricular reconstruction by Smith 1917 [25]. a The flap is incised and prepared. b The flap is sutured into position (in a second stage, the flap is separated in the mastoidal region).

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Fig. 13. Laterally based posterior flap for auricular reconstruction by Ombredanne 1931 [26]. a Insertion of the flap. b Dissection and suturing in a second stage.

Fig. 14. Large, superiorly based, postauricular, cervical, incised flap for partial ear reconstruction by Joseph 1910 [9, 27, 28].

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Fig. 15. Anterosuperiorly based flap described by Crikelair in 1956 [29, 31]. a The flap is incised and sutured to the defect. b Posterior view: the contours are formed with mattress sutures (the flap is dissected after 3 or 4 weeks).

History of Auricular Reconstruction

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Fig. 16. Postauricular inferiorly based flap for reconstruction of the lower part of the auricle described by Gillies in 1920 [32] (see also, fig. 18). a The flap is outlined. b The flap is swung down and doubled. c, d The flap is sutured in place, and the raw surface covered with a free graft.

Fig. 17. Central conchal defect closed by a postauricular U-shaped advancement flap [33]. a Flap outlined and incised. b Flap inserted.

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conchal graft

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Fig. 18. Gavello flap in 1907 [34] in a modification described by Weerda 2004 and 2007 [4, 5] (see also, fig. 24). With this anteriorly based bi-lobed flap, the anterior and posterior surfaces can be reconstructed in a 1-stage procedure.

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Fig. 19. Helical reconstruction with a tubed pedicle flap from the neck (a, b) [37] and from the supraclavicular region described by Pierce in 1925 (c) [38].

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Fig. 20. Helix reconstruction with a tubed pedicle flap. a Supra-auricular bi-pedicled flap. b Retroauricular flap of the sulcus. c Retroauricular flap is inserted. d Preauricular tubed pedicle flap [4, 5, 42, 43].

A very exceptional flap is the bi-lobed flap for the reconstruction of the lower part of the auricle (fig. 18). This Gavello flap [34] was first mentioned in 1870 by von Szymanowski (see fig. 24a) [14]. Tubed Flaps Tube-pedicled flaps from the neck [35, 36] were first used for ear reconstruction by Pierce [37] in 1925 (fig. 19), although they fell out of use due to the conspicuous scars (see fig. 29) and the wrong color match. Supraclavicular flaps are better and were used by Pierce [38], Peek and many other authors. Pre-, post- and retroauricular pedicled and/or tube pedicled flaps can be employed for all regions of the helix. The first bi-pedicled flap of the mastoid was used by Streit [39] in 1914 to reconstruct the helix and anthelix.

History of Auricular Reconstruction

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Fig. 21. Free composite graft for reconstruction of the upper auricle as described by Lexer in 1910 [47]. a The unfolded composite graft is sutured to the raw surface and the lobule is formed. b Result after corrective surgery.

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Fig. 22. Reconstruction of a wedge-shaped defect of the ear with a composite graft from the contralateral ear, as described by Day in 1921 [48] and Pegram and Peterson in 1956 [49]. Tumor excision (a) and full-thickness composite graft (b; half size) from the contralateral ear. Reconstruction of the right ear (c) and closure of the donor defect (d).

Reports on similar tubed flaps were published by Maliniac [40] in 1946, Steffanoff [41] in 1948 and by Converse [42] in 1958 (fig. 20). Composite Grafts A pedicled composite graft of the anthelix (used to reconstruct the upper auricle) was described by Lang [44] in 1872, and later on by Gillies [32] in 1920, Eitner [28] in 1934 and Millard [45] in 1966, who described different chondrocutaneous flaps. Free composite grafts for partial ear reconstruction were used by Körte [46] in 1905 and Lexer [47] in 1910 (fig. 21). Similar techniques have been described by Day [48] in 1921, Pegram and Peterson [49] in 1956 (fig. 22), Nagel [50] in 1972 and Brent [51] in 1975.

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Fig. 23. Partial or total ear reconstruction with the temporoparietal facial flap (fan flap) as described by Fox and Edgerton in 1976 [52]. a, b Harvesting the pedicled fan flap. c The cartilaginous support is enveloped by the flap. d A full-thickness skin graft is sutured to the fan flap. e Result (surgeon. R. Siegert). f, g One of our patients, treated with a fan flap after the loss of a replanted ear (reprinted with permission from Thieme) [5].

History of Auricular Reconstruction

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Fig. 24. Total reconstruction of the auricle by von Szymanowski in 1870 [14]. a, b The outline for the skin for the posterior surface is partially lying in the hair-bearing area. Result after the first stage. c, d Corrective surgery.

Temporoparietal Fascial Flap (Fan Flap) As shown in figure 23, if there is a lack of skin or we want to have good protection for the alloplastic framework, a temporoparietal fascial flap can be harvested (pedicled at the temporal vessels), first described by Fox and Edgerton in 1976 [4, 5, 52–55]. Skin Expansion The first use of the expansion of skin dates back to Neumann [56]. He implanted a balloon in the mastoidal region and then filled it with air several times via an externally

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Fig. 25. Reconstruction with some cartilage and 3 flaps by Schanz in 1890 [59].

placed port. He practised this expansion over a period of 2 months. This method remained relatively unknown for many years and was rediscovered in 1976 for breast reconstruction [57]. For ear reconstruction Siegert et al. [58] carried out a lot of such experiments on animals.

Reconstruction of Total Loss of the Auricle

Total Loss Reconstruction before 1950 Julius von Szymanowski in 1870 [14] was the first to suggest total reconstruction. Figure 24 shows that the main part of the skin material required for the posterior surface of the auricle actually lies in the hair-bearing part of the head, and furthermore the lack of any support is clearly shown. Personally, I believe that he never carried out this operation [4, 5]. In 1890, Schanz [59] described a reconstruction after an almost complete avulsion where remnants of the helical crus were preserved and the anthelix was probably still available with some cartilage as well (fig. 25). The techniques using free composite grafts by Körte in 1905 [46] and Lexer in 1910 [47] are described in the section ‘Partial reconstruction’. Schmieden in 1908 [60] was the first to insert a supportive framework made of autogenous costal cartilage (fig. 26a); however, the result was not very satisfying (fig. 26b).

History of Auricular Reconstruction

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Fig. 26. The first support of costal cartilage was used by Schmieden in 1908 [60] with a flap harvested from pectoral skin (a). The auricle was reconstructed, and the flap transported via the arm (see fig. 4) to the ear (b).

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Fig. 27. Beginning of a ‘modern’ ear reconstruction: transplantation of the cartilaginous support by Gillies in 1920 [32]. a Autogenous cartilage framework. b Incision along the hairline; the carved autogenous cartilage framework from the 6th and 7th ribs is inserted to the mastoid region. c Result after the first stage (the lobule is reconstructed with a small neck flap in a second stage).

Fig. 28. Reconstruction by Esser in 1921 [62]. a Cartilaginous framework. b Result. For helical reconstruction, Esser used a tubed neck flap.

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Fig. 29. A patient sent to us after several attempts at auricular reconstruction with a silicone support and a tubed neck flap. Severe scaring in the mastoidal region and in the neck can be seen (reprinted with permission from Thieme) [5] (see fig. 28b).

Gillies [32] in 1920 was the first to take up the suggestion of Schmieden [60], and he developed a method of reconstruction which became the model for later modern operative methods [61]. He implanted the carved autogenous cartilage framework into the mastoid region (fig. 27) after incising along the hairline. In 1921, Esser [62] reconstructed the auricle in a similar way with a carved cartilaginous support from the 6th and 7th ribs, using a tubed neck flap for helical reconstruction (fig. 28). These flaps [38, 63, 64] caused unshapely scar formations and poor cosmetic results (figs. 28b, 29). In a second stage, the ear was elevated and the raw surface was covered with a split-thickness skin graft. Though most surgeons at this time used an autogenous rib cartilage framework, alloplastic supports were also described, such as ivory (by Joseph [9] in 1931; fig. 30), silicone, metal, rubber, acrylate, Teflon or porous polyethylene materials. Also, xenogenic cartilage – preserved in alcohol, rhimerosal (Merthiolate) or other chemical solutions –was used. In 1986, Toplak [65] listed about 2,500 cases of total auricular reconstructions as reported in the literature, of which only about 165 were reconstructed before 1950. Most authors at this time were not satisfied with the results of total ear reconstruction [7, 63, 66–69]. Dieffenbach [13] wrote in 1845: ‘I consider the replacement of the whole ear to be an entirely inappropriate experiment because it will be impossible to lend the ear its necessary form. Despite all attempts, the ear will remain an unshapely, disfigured lump.’ Sultan [70] remarked in 1907: ‘The replacement of the missing ear with the aid of plastic surgery has been attempted, but any success has been less than satisfying,

History of Auricular Reconstruction

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Fig. 30. An alloplastic ivory framework implanted by Joseph in 1931 [9]. a, b Skin flap from the neck. c Ivory support. d Result.

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given the complexity of the auricular architecture.’ Lexer [69] wrote in 1921: ‘The replacement of a completely absent ear has been attempted, but so far no more than a fairly crude substitute of a construction has been created.’ In 1937, Gillies [68] reported on the disappointing results of his own reconstructive methods and of all those known to him.

Total Reconstruction after 1950 With the modern techniques presented here, we have been able to manage most total losses of the auricles or second-degree and the third-degree dysplasias.

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Fig. 31. Tanzer [73] described his method in 1959. a, b Stage I: the vestige is rotated to form the new lobule. c Stage II: cartilaginous support of the 6th, 7th and 8th ribs. d, e, f Insertion of the support; the contours are formed by mattress sutures. A full-thickness skin graft is used to cover the defect in the concha. g Stage III: elevation of the ear and grafting of the defect. h, i Stage IV: construction of the tragus and the conchal cavity.

Tanzer’s Reconstruction A IV-stage concept was proposed by Tanzer [61, 71–73] in 1959 in the case of grade III microtia:

History of Auricular Reconstruction

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Fig. 32. Brent’s technique in 1987 [74] in a modification by Weerda and Siegert in 1994 [75]. a, b Stage I: preparation of a tragus flap, removal of rudimentary cartilage, tunneling of the mastoidal skin. c, d Insertion of the framework and contouring the auricle using mattress sutures and vacuum drains. For stage II, see figure 31f, g [4, 5].

Stage I: rotation of the lobule (fig. 31a, b). Stage II (2 months later): carving a support made of costal cartilage from the 6th, 7th and 8th ribs (fig. 31c); a pocket is prepared and the support is inserted (fig. 31d, e). As an alternative, Tanzer combined stages I and II, as did later his assistant Burt Brent [74] (fig. 32). Stage III: 3 or 4 months later, the ear is incised along the auricular contour, and lifted from the side of the head; a thick split-thickness skin graft is inserted, and thus an auriculocephalic sulcus is created (fig. 31g).

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Fig. 33. Nagata’s technique described in 1994 [76, 77] modified by Weerda and Siegert in 1998 (reproduced with permission from Thieme) [5]. a, b, c Stage I: 3D cartilaginous support. Outline of the anterior and posterior aspect of the remnant. d, e Insertion of the support, closure and mattress sutures. f, g, h Stage II: elevation of the auricle (our modification).

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Fig. 33. i, j The wound of the mastoid is covered with a thick split skin graft. k–m Result after operation of a third-degree microtia with rib cartilage, using a modification of Nagata’s technique.

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Stage IV: some months later, corrections – such as deepening of the concha or forming a tragus etc. – are carried out (fig. 31g). Brent’s Technique In a similar way, Brent in 1987 [74] carried out his auricular reconstruction in 2 or 3 stages (fig. 32). Nagata’s Technique The technique used by Nagata (1994) has 2 stages [76–80]. Stage I: after carving a 3D framework (fig. 33a), a special incision technique is performed (fig. 33b, c), and the support is inserted and contoured with a few mattress sutures tied over cotton bolsters; the auricle is molded without pressure (fig. 33d, e). Stage II: incision above the framework and dissection and elevation of the auricle are carried out (fig. 33f, g, h, i, j).

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Fig. 34. ‘Replantation’ of the avulsed ear by Jesus Christ (wood carving, Groenau altar, 15th century, St. Annen Museum, Lübeck, Germany).

Replantation of the Auricle

The total amputation of the ear was reported in St. Luke’s Gospel, when Simon Peter cut off the ear of Malchus (fig. 2), and the ear was ‘replanted’ by Jesus Christ (fig. 34). The successful survival of a severed and replanted ear was reported in the 17th, 18th and 19th centuries [3, 7, 42, 81]. The classic replantation shows a poor survival rate of 27%; with Baudet’s [82] and Arfai’s [83] techniques, the survival rate is 38% [24]; with pocket techniques [84–86], the survival rate increases to 64% [5]. The first experimental microvascular anastomoses of the amputated ears of rabbits were reported in 1966 by Buncke and Schulz [87]. With improved techniques [88–91], the survival rate has increased to 60% [4, 5].

References 1 de River JP: Restoration of the auricle. Cal West Med 1927;26:654–656. 2 McDowell F: The Source Book of Plastic Surgery. Baltimore, Williams & Wilkins, 1977. 3 Zeis E: Von der Otoplastik oder Ohrbildung; in Zeis E: Handbuch der plastischen Chirurgie, ed 4. Berlin, G Reimer, 1838, pp 464–468.

History of Auricular Reconstruction

4 Weerda H: Chirurgie der Ohrmuschel: Verletzungen, Defekte und Anomalien. Stuttgart, Thieme, 2004. 5 Weerda H: Surgery of the Auricle: Tumors. Trauma, Defects, Abnormalities. Stuttgart, Thieme, 2007.

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6 Mündnich K: Die wiederherstellende Ohrmuschelplastik; in Sercer A, Mündnich K: Plastische Operationen an der Nase und an der Ohrmuschel. Stuttgart, Thieme, 1962, pp 325–382. 7 Zeis E: Die Geschichte der Otoplastik; in Zeis E: Die Literatur und Geschichte der plastischen Chirurgie. Leipzig, W Engelmann, 1838 (reprinted by Amaldo Forini, Bologna, 1963, pp 270–275). 8 Tagliacozzi I: De curtorum chirurgia per institionem. Venetia, Libri duo, 1597 (reprinted and edited by Max Troschel, G. Reimer, Berlin, 1931). 9 Joseph J: Ohrdefekte (Otoneoplastik): in Joseph J: Nasenplastik und sonstige Gesichtsplastik, ed 3. Leipzig, Kabitzsch, 1931, pp 717–736. 10 Paré A (1510–1590); cited in: Roberts AC: Facial Prostheses, ed 2. London, Kenry Kimpton, 1971. 11 Roux PPE (1894); cited in: Roberts AC: Facial Prostheses, ed 2. London, Kenry Kimpton, 1971. 12 Roberts AC: Facial Prostheses, ed 2. London, Kenry Kimpton, 1971. 13 Dieffenbach JF; in Fritze HE, Reich OF (eds): Die Plastische Chirurgie in ihrem weitesten Umfang dargestellt und durch Abbildungen erläutert. Berlin, Hirschwald, 1845. 14 von Szymanowski J: Ohrbildung, Otoplastik; in von Szymanowski J: Handbuch der operativen Chirurgie. Braunschweig, F Vieweg & Sohn, 1870, pp 303–306. 15 Di Martino G: Anomalie de pavillon d’oreille. Bull Acad Natl Med 1856/1857;22:17. 16 Cocheril G; cited in: Converse JM: Reconstructive Plastic Surgery. Philadelphia, Saunders, 1977, pp 1671–1719. 17 Joseph J: Demonstration operierter Eselsohren. Verl Berl Med Ges 1896;I:206. 18 Gersuny R: Über einige kosmetische Operationen. Wien Med Wschr 1903;48:2253–2257. 19 Antia N, Buch V: Chondrocutaneous advancement flap for the marginal defects of the ear. Plast Reconstr Surg 1967;39:472–477. 20 Argamaso RV, Lewin M: Repair of partial ear loss with local composite flap. Plast Reconstr Surg 1968; 42:437–441. 21 Lexer E: Die gesamte Wiederherstellungschirurgie. Leipzig, Barth, vol 1, 1933, p 441. 22 Meyer R, Sieber H: Konstruktive und rekonstruktive Chirurgie des Ohres; in Gohrbrandt E, Gabka J, Berndorfer A (eds): Handbuch der plastischen Chirurgie. Berlin, De Gruyter, 1973, pp 1–62. 23 Tenta LT, Keyes GR: Reconstructive surgery of the external ear. Otolaryngol Clin North Am 1981;14: 917–938. 24 Weerda H, Zöllner C: Chirurgie der Tumoren an der alternden Haut der Ohrregion; in Neubauer H (ed): Plastische und Wiederherstellungschirurgie. Berlin, Springer, 1986.

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25 Smith H: Plastic operation for restoration of the auricle, following injury from an explosion. Ann Otol Rhinol Laryng 1917;26:831–833. 26 Ombredanne L: Reconstruction autoplastique de la moitié du pavillon de l’oreille. Presse Med 1931;53: 982–983. 27 Joseph J (1910); cited in: Joseph J: Nasenplastik und sonstige Gesichtsplastik. Leipzig, Kabitzsch, 1931. 28 Eitner E: Ohrmuschelersatz. Dtsch Zschr Chir 1934; 2422:797–801. 29 Crikelair G: A method of partial ear reconstruction for avulsion of the upper portion of the ear. Plast Reconst Surg 1956;17:438–443. 30 Pollet J: Chirurgie plastique et reconstructive du pavillon de l’oreille. Arnette Med France 1966;73: 535–539. 31 Goedecke C: Geschichte des plastisch-rekonstruktiven Chirurgie von erworbenen Ohrmuscheldefekten [Dissertation]. Mediz. Universität zu Lübeck, 1995. 32 Gillies HD: Injuries to the pinna; in Gillies HD (ed): Plastic Surgery of the Face. London, Forwde, Hodder an Stoughton/Oxford University Press, 1920, pp 381–387. 33 Gingrass RP, Pickrell KI: Techniques for closure of conchal and external auditory canal defects. Plast Reconstr Surg 1968;41:568–571. 34 Gavello P; cited in: Nelaton C, Ombredanne L: Les autoplasties: levres, joues, oreilles, tronc, membres. Paris, Steinheil, 1907. 35 Filatow WB (1977): cited after. 36 Filatow WB: Plastik mit rundem Stiel. Klin Monatsbl Augenhlkd 1922;68:124–132. 37 Pierce GW (1925); cited in: Naumann HH (ed): Kopf and Hals Chirurgie. Stuttgart, Thieme, 1976. 38 Pierce GW: Reconstruction of the external ear. Surg Gynecol Obstet 1930;50:601–605. 39 Streit R: Einige plastische Operationen an der Ohrmuschel. Arch Ohrenheilk 1914;95:300–303. 40 Maliniac J: Reconstruction for partial loss of ear. Plast Reconstr Surg 1946;1:124–129. 41 Steffanoff DN: Auriculo-mastoid tube pedicle for otoplasty. Plast Reconstr Surg 1948;3:352–360. 42 Converse JM: Reconstruction of the auricle, part 1 and 2. Plast Reconstr Surg 1958;22:150–163, 230– 249. 43 Converse JM, Brent B: Acquired deformities; in Converse JM (ed): Reconstructive Plastic Surgery, ed 2. Philadelphia, Saunders, 1977, vol 3, pp 1724– 1733. 44 Lang E: Ein Fall von partieller Otoplastik. Arch klin Chir 1872;14:406–408. 45 Millard DR: The chondrocutaneous flaps in partial auricular repair. Plast Reconstr Surg 1966;37:523.

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46 Körte W: Fall von Ohrenplastik: Sitzung am 13.11.1905. Verh Fr Vrgg Chir Berlins 1905;18:91– 92. 47 Lexer E: Zur Gesichtsplastik. III. Ersatz der Ohrmuschel. Arch Klin Chir 1910;92:774–793. 48 Day HF: Reconstruction of ears. Boston Med Surg J 1921;185:146–147. 49 Pegram N, Peterson R: Repair of partial defects of the ear. Plast Reconstr Surg 1956;18:305. 50 Nagel F: The reconstruction of partial auricular loss. Plast Reconstr Surg 1972;49:340. 51 Brent B: Reconstruction of ear, eyebrow and sideburn in the burned patient. Plast Reconstr Surg 1975;55:312–317. 52 Fox WJ, Edgerton MT: The fan flap: an adjunct to ear reconstruction. Plast Reconstr Surg 1976;58:663– 667. 53 Brent B, Byrd HS: Secondary ear reconstruction with cartilage grafts covered by axial, random, and free flaps of temporoparietal fascia. Plast Reconstr Surg 1983;72:141–151. 54 Erol Ö, Don Parsa F, Spira M: The use of the secondary island graft flap in reconstruction of the burned ear. Br J Plast Surg 1981;34:417–421. 55 Tegtmeier R, Gooding R: The use of a fascial flap in ear reconstruction. Plast Reconstr Surg 1977;60:406– 411. 56 Neumann CG: The expansion of an area of skin by progressive distension of a subcutaneous balloon. Plast Reconstr Surg 1957;19:124–130. 57 Redovan C: Advantages and complications of breast reconstruction using temporary expander. Plast Surg Forum 1980;3:63–68. 58 Siegert R, Weerda H, Hoffmann S, Mohadjer C: Klinische und experimentelle Untersuchungen zur intermittierenden, intraoperativen Kurzzeitexpansion. Arch Ohren Nasen Kehlkopfheilkd 1991; (suppl 2):223–224. 59 Schanz F: Wiederersatz einer verlorengegangenen Ohrmuschel: Korrespondenz-Blätter des allgem Ärztl Vereins von Thüringen. 1890;19:288–293. 60 Schmieden V: Der plastische Ersatz von traumatischen Defekten der Ohrmuschel. Berl Klin Wschr 1908;45:1433–1435. 61 Tanzer RC: Total reconstruction of the external ear. Plast Reconstr Surg 1959;23:1–15. 62 Esser JFS: Totaler Ohrmuschelersatz. Münch Med Wschr 1921;36:1150–1151. 63 König F: Die Krankheiten des äußeren Ohres; in König F: Lehrbuch der speziellen Chirurgie für Ärzte und Studierende. Berlin, Hirschwald, 1885, vol 1, 475–476. 64 Padgett EC: Total reconstruction of the auricle. Surg Gynecol Obstet 1938;67:761–768.

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65 Toplak FH: Die Totalrekonstruktion der Ohrmuschel; Disseration, Berlin, Universitätsklinikum Steglitz, 1986. 66 Beck J: Über die plastischen Operationen an Nase und Ohr. Internat Zbl Ohrenhlkd 1923;21:134. 67 Fritze HE, Reich OFG: Von der Otoplastik (Ohrbildung); in Fritze HE, Reich OFG: Die plastische Chirurgie, in ihrem weitesten Umfange dargestellt und durch Abbildungen erläutert. Berlin, Hirschwald, 1845, pp 110–111. 68 Gillies HD: Reconstruction of the external ear with special reference to the use of maternal ear cartilage as the supporting structure. Rev Chir Structive 1937;7:169–179. 69 Lexer E: Otoplastik, Ohrbildung; in Coenen et al. (eds): Chirurgie des Kopfes. Stuttgart, Enke, 1921, pp 731–735. 70 Sultan G: Chirurgie. München, Lehmann JF, 1907. 71 Tanzer RC: An analysis of ear reconstruction. Plast Reconstr Surg 1963;31:16–30. 72 Tanzer RC: Correction of the microtia with autogenous costal cartilage; in Tanzer RC, Edgerton MT (eds): Symposium on reconstruction of the auricle. St. Louis, CV Mosby & Co, 1974, pp 46–57. 73 Tanzer RC, Bellucci RJ, Convers JM, Brent B: Deformities of the auricle; in Converse JM (ed): Reconstructive Plastic Surgery. Philadelphia, Saunders, 1977, pp 1671–1719. 74 Brent B: Auricular repair with a conchal cartilage graft; in Brent B (ed): The Artistry of Reconstructive Surgery. St. Louis, CV Mosby & Co, 1987, pp 107– 112. 75 Weerda H, Siegert R: Auricular and Middle Ear Malformations, Ear Defects and their Reconstruction. The Hague, Kugler, 1998. 76 Nagata S: A new method of total reconstruction of the auricle for microtia. Plast Reconstr Surg 1993; 92:187–201. 77 Nagata S: Modification of the stages in total reconstruction of the auricle. I. Grafting the three-dimensional costal cartilage framework for lobule-type microtia. Past Reconstr Surg 1994;93:221–230. 78 Nagata S: Modification of the stages in total reconstruction of the auricle. II. Grafting the threedimensional costal cartilage framework for concha type microtia. Plast Reconstr Surg 1994;93:231–242. 79 Nagata S: Modification of the stages in total reconstruction of the auricle. III. Grafting the threedimensional costal cartilage framework for small concha type microtia. Plast Reconstr Surg 1994;93: 243–253. 80 Nagata S: Modification of the stages in total reconstruction of the auricle: IV. Ear elevation for the constructed auricle. Plast Reconstr Surg 1994;93: 254–266.

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81 Kazanijian V: Surgical treatment of congenital deformities of the ear. Am J Surg 1958;95:185– 188. 82 Baudet J: La réimplantation du pavillon de l’oreille mutilé. Nouv Presse Med 1972;5:344–346. 83 Arfai (1874); cited in: Spira M, 1963 84 Mladick R, Horton C, Adamson J, Cohen B: The pocket principle. Plast Reconstr Surg 1971;48:219– 223. 85 Mladick R, Curraway J: Ear reattachment by the modified pocket principle. Plast Reconstr Surg 1973;51:584–587. 86 Sexton RP: Utilization of the amputated ear cartilage. Plast Reconstr Surg 1955;15:419–422.

87 Buncke H, Schulz W: Total ear reimplantation in the rabbit utilising microminiature vascular anastomoses. Br J Plast Surg 1966;19:15–22. 88 Giesen van P, Seaber A, Urbaniak J: Storage of amputated parts prior to replantation – an experimental study with rabbit ears. J Hand Surg 1983; 8: 60–65. 89 Juri J, Irigaray, Juric, Grilli D, et al: Ear replantation. Plast Reconstr Surg 1987;80:431–435. 90 Safak T, Özcan G, Kecik A, Gürsu G: Microvascular ear replantation with no vein anastomosis. Plast Reconstr Surg 1993;92:945–950. 91 Tsai T: Experimental and clinical application of microvascular surgery. Ann Surg 1975;181:169– 171.

Hilko Weerda, MD, DMD, Professor and Former Head Department of Otorhinolaryngology and Plastic Surgery, Medical University of Lübeck Steinhalde 48 DE–79117 Freiburg (Germany) E-Mail [email protected]

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Staudenmaier R (ed): Aesthetics and Functionality in Ear Reconstruction. Adv Otorhinolaryngol. Basel, Karger, 2010, vol 68, pp 25–52

State-of-the-Art Autogenous Ear Reconstruction in Cases of Microtia F. Firmin Clinique Bizet, Paris, France

Abstract Ear reconstruction is considered to be a challenging form of surgery. In cases of microtia, surgeons must reconstruct complex missing contours, which necessitates the use of a support and skin remnants to cover this support. Although the use of synthetic material has been proposed in order to avoid harvesting and carving cartilage, the best long-term choice for reconstructing an ear is autologous rib cartilage. This procedure requires good understanding of the 3-dimensional architecture of the ear and learning the step-by-step construction of a harmonious framework (which with practice will become the most straightforward part of the procedure). Surgery, usually performed at the age of 9 or 10 years, is planned in 2 stages. In the first stage, the framework is placed under a skin pocket. Six months later, the sulcus is created using an additional cartilage graft for projection and a skin-grafted galeal fascial flap. In order to shorten the learning curve, a detailed carving process is described here, as well as a tool to enable training before surgery. Remnants of the microtic ear can have many different shapes; therefore, a comprehensive approach to skin management is proposed, providing a simple surgical classification for all types of microtia. Furthermore, some refinements of the cartilage framework and the construction of the retroauricular sulcus have improved results. Whenever possible, successful reconstruction of a microtic ear with autologous rib cartilage, as opposed to synthetic materials, is by far the best option. Copyright © 2010 S. Karger AG, Basel

The external ear has a 3-dimensional architecture with complex contours. When reconstructing an ear, the goal is to reproduce these contours as closely as possible to those of a normal ear. This implies the use of a support, usually made of autologous rib cartilage. The quality of the results depends on 2 factors: (1) precise preparation of the 3-dimensional cartilaginous support; (2) an appropriate strategy to adapt the skin remnants to the cartilaginous framework. Carving an autologous rib cartilage framework becomes, after a steep learning curve, the most routine part of the reconstruction. However, using the available skin to cover the framework and choosing best skin approach for each case remain challenges.

In most cases, the reconstruction is performed in 2 stages: (1) insertion of the framework under the skin; (2) elevation of the reconstructed ear, recreating the retroauricular sulcus.

First Stage

Cartilaginous Framework Harvesting the Rib Cartilage Segments Rib cartilage is the only place on the body that provides enough cartilage for a total ear reconstruction [1]. We usually wait until patients are 10 years old to harvest enough cartilage, which is also the age when the opposite ear reaches adult size. The cartilage is harvested from the ipsilateral side of the microtia through a 4to 5-cm oblique skin incision. The 8th rib is very often used for the helix because of its adequate length. The 9th rib is shorter, but can be harvested if there is a need for more material. The base of the framework comes from the 6th and 7th ribs, including the synchondrosis. A template of the normal ear, on sterile X-ray film, will assist in determining the amount of cartilage needed and the shape that fits best (i.e. cartilage from the 5th and 6th ribs versus the 6th and 7th ribs; fig. 1). The posterior perichondrium is not harvested. For carving, the cartilage is turned upside down, so that the anterior perichondrium now constitutes the posterior surface of the framework. No drains are used. A piece of cartilage is placed under the thoracic skin, in preparation for the second stage to reconstruct the concha. The deformation at the donor site is minimal, and we have never had to perform long-term corrections [2, 3]. Pain at the donor site can be significantly diminished by an intercostal block with ropivacaine injected at the inferior borders of the 6th to 9th ribs; this is very well tolerated by the children. Hence, our long-term experience tells us that one cannot use donor site sequelae as a reason to justify using synthetic material or taking a minimal cartilage harvest. Carving the framework should not be an obstacle either, as this can be mastered after a steep learning curve [4]. Sculpture of the Framework The preparation of the framework follows a well-established step-by-step procedure (fig. 2). The base is carved first, deepening the area of the scapha and triangular fossa, and then the different pieces are added to reproduce the 3-dimensional architecture of the ear. These pieces are the anthelix, the helix and tragus-antitragus complex. They are fixed to the base with 5/0 Steelex® stainless steel threads, double-armed with straight GS atraumatic needles (Ear Set, B. Braun, Melsungen, Germany).

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Fig. 1. Harvesting autologous rib cartilage. a Three or four segments of rib cartilage (6th to 9th) are harvested on the side ipsilateral to the microtia, leaving the posterior perichondrium intact. b The cartilage is turned over and the different pieces needed to construct the framework are drawn using the template based upon the contralateral ear, selecting the best construction possible. The different pieces will be fixed on the base, which is typically drawn on 2 adjacent ribs, over a synchondrosis.

a

b

Fig. 2. The different steps of construction of a complete framework. a The 2 extremities of the framework are deepened. b The scapha and triangular fossa are carved. c The piece reproducing the anthelix is fixed to the base using wire sutures. d The piece reproducing the helix is also fixed to the base. e A V-shaped piece is added. f The new piece is carved to reproduce the tragus and antitragus.

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Fig. 3. Construction of a complete framework. a Three segments of rib cartilage have been harvested. b Fixation of a piece of cartilage to ensure fixation of the root of the helix. c The V-shaped segment for reproducing the tragus and antitragus is added. d The completed framework. e The inferior part of the framework is inserted into the lobular remnant and the superior part is covered with a retroauricular skin flap.

Nagata [5–7] was the first person to advocate reconstructing the tragus and transposing the lobule during the first stage in cases of microtia. This approach reduced the number of stages from 4 (in Brent’s technique) to 2. This first stage thus corresponds to the first 3 stages of Brent’s technique [8, 9]. Our main personal modifications concerning the preparation of the framework are the 3-dimensional sculpture of the tragus-antitragus complex and the use of an extra piece to improve the projection of the anterior part of the framework [2–4, 10–13] (fig. 3). Sadly, some surgeons have abandoned ear reconstruction or prefer to use a synthetic material like Medpor [14–18] in order to avoid harvesting cartilage and sculpting a delicate framework during surgery. Their published results are poor by comparison. Another concern is the fact that they advocate the immediate use of the galeal fascial flap to cover the Medpor and diminish the risk of exposure, which renders revision

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Fig. 4. a Training device to help the surgeon practice sculpting a framework before surgery. b Assessment under a rubber plate that simulates the skin.

surgery extremely difficult. Training to learn how to sculpt the 3-dimensional framework before performing a total ear reconstruction is not only possible, but mandatory. We have designed a device called the ‘trainer’ (Stortz, Tuttlingen, Germany) to help the surgeon sculpt and train at home before surgery (fig 4). The quality of the carving can be assessed by placing it under a rubber plate that simulates the skin. When suction drainage is applied, the contours of the framework will appear and offer the chance of critical observation. Of course, carving several frameworks before surgery may seem too much effort for the occasional ear reconstruction. However, reconstructing an ear using autologous cartilage without any training and without having a clear understanding of the 3-dimensional architecture of the ear would certainly lead to a poor clinical result. Once the complete framework is memorized, it becomes easy to adapt to various local conditions. For instance, sometimes there is no need to reconstruct the tragus and the antitragus because they already exist.

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Fig. 5. Classification of the different types of framework used to correct microtia. a Type I: complete framework. b Type II: framework without tragus. c Type III: framework without tragus and antitragus.

Fig. 6. A typical framework. An additional piece, which we have named ‘surelevation’, gives more projection and stability to the root of the helix and the tragus.

Fig. 7. Results obtained before using the ‘surelevation’ behind the root of the helix and the tragus. a Former framework. b The area located behind the root of the helix is flat, due to the lack of projection of the tragus and root of the helix.

Therefore, we have categorized 3 possible frameworks to be used when correcting microtia (fig. 5): type I (a complete framework), type II (no tragus) and type III (no tragus or antitragus). The choice between these 3 types will of course be dictated by the presence or absence of the normal tragus and/or antitragus.

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Fig. 8. Results obtained with the ‘surelevation’. a Preoperative appearance. b, c Anterior and posterior views of the framework. d Improvements in the results, clearly showing more accentuated and natural contours.

Recent Improvement Concerning the Framework For the last 3 years, we have routinely placed an additional piece of cartilage (which we call the ‘surelevation’) behind the root of the helix and the tragus. This very simple addition has improved our results by accentuating some contours and by giving more projection and stability to the tragus and the root of the helix (fig. 6). The improvement obtained from adding this additional piece to the framework has been demonstrated in clinical cases (fig. 7, 8).

Skin Approach Microtia is observed in many different circumstances. It can be isolated or part of a syndrome such as hemifacial microsomia, Goldenhar or Franceschetti [19–21].

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Fig. 9. Type 1 skin approach. a Placement of the incision (Z-plasty). b Elevation of the flap. c Exchange of the skin flaps. d Aspect at the end of the procedure.

Whatever the circumstances, many different shapes of microtic remnants can be observed, and it is very important to choose the skin approach that will allow the most appropriate use of the remnants to cover the framework. We have created a surgical classification that includes 3 types of skin approach. When keeping these 3 possible skin approaches in mind, it is easy to select the most appropriate one for any type of microtia. Type 1 The type 1 incision allows an exchange of 2 flaps, like in a Z-plasty, where one of the flaps includes the lobule (fig. 9). Type 2 Type 2 is a transfixion incision (skin and fibrocartilage) that is used to obtain adhesion of part of the remnants to the retroauricular skin. An additional back cut is made to suture the posterior edge of the incision to the mastoid skin. This creates a pocket

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Fig. 10. Type 2 skin approach. a Transfixion incision of the remnants. b Adhesion of the posterior edge of the transfixion incision to the inferior edge of the back cut. c The inferior part of the framework is introduced into the lobule. d The superior part of the framework is covered with a retroauricular skin flap.

for the inferior portion of the framework which, once inserted, re-creates the lobule. The superior part of the framework is elevated in a second stage (fig. 10). Type 3 Type 3 is only a skin incision, and is used in two extreme situations: (1) Type 3a is used when the ear has a normal size (enough skin), but the fibrocartilage is deformed. After removing the fibrocartilage, the framework is inserted into the skin pocket. As the sulcus is preserved, only 1 stage is necessary (fig. 11). (2) Type 3b is used when there are no remnants, or when they are very much misplaced and cannot be used (fig. 12). Before choosing the skin approach, it is important to decide on the location of the reconstructed ear. Measurements are taken on the opposite side, which include: the distance between the lateral canthus and the most anterior point of the helix; the distance between the lateral commissure and the lowest point of the lobule; the angle between the dorsum of the nose and the axis of the normal ear.

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Fig. 11. Type 3a skin approach (can only be performed in 1 stage). a The skin incision gives access to the deformed fibrocartilage. b Through removal of the fibrocartilage, a skin pocket has been created to receive the framework. c The framework is introduced into the skin pocket, replacing the deformed fibrocartilage. d The anterior and posterior surfaces of the framework are covered with skin.

Fig. 12. Type 3b skin approach. a As there are no remnants to remove, the skin incision is only used to prepare the skin pocket. b The framework is introduced into the skin pocket, and the small ectopic remnant will be removed during the second stage (i.e. elevation of the template).

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a

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Fig. 13. Clinical example of type 1. a, b Drawing of the Z-plasty that will allow a posterior transposition of the lobule. The path of the superficial temporal artery has been marked out to avoid damage during preparation of the skin pocket. c Type I framework. d Final result after 1 year, with a very discrete scar at the junction with the transposed lobule.

The exact position is marked with a template, and confirmed by the relationship of the template to the remnants. Whatever skin approach is chosen, the skin flap is raised extremely carefully, in order to minimize damage to the sub-dermal vessels. Fibrocartilage remnants are removed using the same incision in order to prepare the pocket for the framework.

Clinical Examples

Type 1 (Fig. 13) This type of skin approach is used when the lobule is narrow and placed in a correct position. The anterior branch of the Z-plasty is located on the anterior surface

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Fig. 14. Clinical example of type 2. a The upper part of the ear, including the anthelix scapha and helix, has to be reconstructed. b Type III framework. c The inferior part of the framework has been introduced into the lobule after adhesion; the superior part, covered with a skin flap, will be elevated during the second stage. d 1-year followup.

of the lobule, the medial branch is placed just behind the edge of the lobule and the posterior branch determines the location of the lobule after its transposition. To ensure good vascularization of the tip of the flap that will cover the lower portion of the framework, the posterior branch of the Z-plasty is drawn as short as possible.

Type 2 (Fig. 14) Type 2 is indicated when the remnants allow the insertion of a portion of the framework (usually the lower part). Only the part of the framework that is not inserted into the lobule will have to be covered by a skin flap and require elevation during a second stage. Type 2 is the type we use most frequently. The principle remains the same

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Fig 15. Clinical example of type 3a. a The size of the remnants, as compared to the size of the other ear, allows insertion of the framework in a single stage. b The deformed fibrocartilage has been removed. c: Good adaptation of the skin to the underlying type III framework. d Final result (obtained in a single procedure).

whatever the type of remnant, but the level of the adhesion which will allow insertion of the framework may vary.

Type 3a (Fig. 15) This type, which is only a skin incision, is used when the contours of the ear are abnormal, but the size of the ear allows insertion of a framework that will replace the deformed fibrocartilage. Even if the ear is smaller than the normal one, the skin elasticity will allow the insertion of a framework that has the size of the opposite ear. This is the only situation where the reconstruction is performed in one stage, because there is no need to reconstruct the retroauricular sulcus as it already exists.

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Fig. 16. Clinical example of type 3b. a Placement of the ear in its ideal location shows that almost no skin remnants can be used to cover the framework. b The skin incision allows dissection of a skin pocket. c Complete type I framework. d After the first stage, all the contours have been reproduced. The entire framework including the lobule will have to be elevated during the second stage.

Type 3b (Fig. 16) This type, which is also only a skin incision, is used when there are almost no remnants allowing the preparation of a skin pocket to fit a complete framework in. It is also used when the remnants do not permit any transposition (type 1) or transfixion incision (type 2). Careful consideration of these 3 possible types of skin approach (Z-plasty, transfixion incision and skin incision ) will lead to the most appropriate one being selected. First, it is essential to draw the contours of the normal ear on a template and place it on the future ideal location. This location is precisely determined by measurements and comparative landmarks on both sides (fig. 17, 18). Once an outline of the ear on the abnormal side has been drawn, analysis of the possible adaptation of the remnants to the future contours of the ear is possible. The choice of skin approach can then be made.

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Fig. 17. Estimation of the ideal location of the reconstructed ear. a In a frontal view, the position of the lobule is compared to the normal side. b Landmarks drawn on the normal side are: a line parallel to the axis of the nose and another one parallel to the axis of the ear. The angle made by these 2 lines is measured. Distances between the external canthus and root of the helix (a–a⬘) and the corner of the mouth and lobule (b–b⬘) are also measured. c. All these landmarks are transferred onto the abnormal side to determine the ideal location of the future ear.

Fig. 18. Landmarks used during surgery to correctly place the reconstructed ear. To avoid any septic contamination, the operating field is limited to the area of the anomaly. It is then essential to follow the established landmarks throughout the procedure. The path of the superficial temporal artery is part of the preoperative evaluation (Doppler probe).

Examples to Demonstrate the Process of Choosing the Best Skin Approach in Some ‘Intermediate Cases’

Type 3 versus Type 1 (Fig. 19) Situation: after drawing the outline of the ideal location of the ear to be reconstructed, the lobule appears too high and too posterior to be taken into a correct position using a Z-plasty. In this case, type 3b (skin incision) would be selected. The skin incision is placed on the lobule to allow some thinning of the skin that will cover the tragus and

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Fig. 19. Type 3 versus type 1. a The lobule is too high and posterior to be transposed to its ideal location using a type 1 skin approach. b Type 3b is used instead. The skin incision will allow preparation of the skin pocket and defatting of the lobule to obtain a good adaptation of the skin to the tragus. c Type I complete framework. d Suction drainage facilitates good adaptation of the skin to the framework. It is better to postpone the excision of some skin excess on the helix to preserve the skin flap blood supply. e Results of stage 1, before elevation of the ear.

preparation of a skin pocket. To avoid any vascular problems, it is better to postpone the excision of excess skin on the helix. This will be done during the second stage when reconstructing the retroauricular sulcus.

Type 2 versus Type 1 (Fig. 20) Situation: even though at first glance type 1 could be chosen, after placing a hook on the lobule and pulling it to its ideal location, it appears that it easily reaches the

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Fig. 20. Type 2 versus type 1. a Landmarks, including the path of the superficial temporal artery. b, c Low type 2 approach has been chosen because the lobule is large enough to reach its ideal position. d The inferior part of the framework is inserted into the lobule, resulting in a very natural aspect after elevation of the superior part of the ear. e Results before the second stage.

outline of the ear. The lower part of the framework would then be inserted after performing a very low type 2 approach, and the implantation of the lobule will look very natural. This is possible when the lobular remnants are an ideal location. In such conditions, we now avoid using type 1. Besides the more natural shape of the lobule, it is safer concerning the vascularization of tip of the skin flap covering the framework. The tip of the flap is drawn with a 90-degree angle (instead of 60°) when performing a Z-plasty.

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Fig. 21. Type 2 versus type 3a. a This ear is not only deformed, but also smaller than the normal one. b Type III framework. c Skin remnants of the upper part of the microtic ear were considered insufficient to cover the upper part of the framework. d A high type 2 skin approach is preferred here. e Results before elevation of the upper part of the reconstructed ear.

Type 2 versus Type 3a (Fig. 21) When the microtic ear looks like a small ear with deformed contours, it is tempting to select type 3a, which would be performed in 1 stage. It is essential to analyze not only the height, but also the width, of the upper part of the abnormal ear compared to the normal one. A precise evaluation will sometimes make it preferable to choose type 2, which would be placed at a high level and to accept a 2-stage reconstruction. With experience, it becomes easier to select the best technical approach.

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Fig. 22. After a skin incision around the outline of the framework, the elevation is performed following its posterior surface, exposing the cartilage. It allows excellent mobilization of the framework and a good elevation after fixation of the extra piece of cartilage, which reproduces the posterior wall of the concha. If needed, it is also possible to thin the posterior edge of the base. The posterior edge of the skin incision is brought forward to the depth of the sulcus. Temporal fascia covers the exposed cartilage, including the posterior wall of the concha, and a split-thickness skin graft (from the scalp) covers the temporal fascia.

Fig. 23. Reconstruction of the retroauricular sulcus. a Elevation of the reconstructed ear is performed 6 months after the first stage. b Skin incision following the posterior surface of framework around the ear, and subsequent elevation. c The cartilaginous piece reproducing the posterior wall of the concha is firmly fixed with wire sutures behind the base. d Good projection of the ear is obtained. e The exposed cartilage is covered with a temporal fascia flap. f Two-year follow-up showing a good color match of the skin graft to the scalp.

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Fig. 24. Coverage of the mastoid area. a After some skin undermining, the posterior non-hair-bearing flap is brought forward to the depth of the sulcus. b To avoid hair in the superior part of the mastoid area, a separate skin graft is applied behind the ear.

Second Stage

The reconstruction of the retroauricular sulcus is performed at least 6 months after the first stage to allow good adaptation of the skin to the underlying contours when fibrosis has been resorbed. Our usual technique for elevation of the reconstructed ear differs from Brent [9, 22, 23] and Nagata [5–7]. Instead of leaving some soft tissues on the cartilage, we expose the posterior surface of the framework while performing the second stage [4] (fig. 22). After a skin incision around the outline of the framework, the dissection exposes almost the entire posterior surface of the base of the cartilaginous graft. No soft tissues, except the skin of the posterior wall of the concha, will then restrain the projection of the entire framework when placing an additional piece to reproduce the wall of the concha (fig. 23). The piece of cartilage stored under the thoracic skin during the first stage must be prepared before being fixed. It has to have the same curvature as the anthelix, to be high enough and to be thinned. Fixation to the posterior surface of the base behind the anthelix must be solid to avoid secondary displacement. Transfixion sutures are used in the 3 planes (wire sutures in the vertical plane and non-resorbable sutures in the horizontal and antero-posterior planes). This will avoid secondary retraction of the sulcus, which is a frequent and unsatisfactory occurrence. A temporal fascial flap with axial vascularization from the superficial temporal artery will cover the posterior surface of the framework as well as the reconstructed posterior wall of the concha. After a large undermining of the retroauricular skin, the posterior skin edge is brought upward and forward to the depth of the sulcus.

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Fig. 25. Case 1. Pre- (a) and postoperative (b) pictures. Technique: skin approach type 1, cartilage framework type I, and elevation of the reconstructed ear following our own technique. The previous piercing was preserved when performing transposition of the existing lobule.

Fig. 26. Case 2. Pre- (a) and postoperative (b) pictures. There was insufficient definition of the root of the helix, and the tragus needed to be accentuated. This case was performed before the routine use of an additional piece of cartilage placed under the tragus and the helix to elevate the anterior contours of the ear. Technique: skin approach type 2, cartilage framework type I, and elevation following our own technique.

To avoid the presence of hair behind the superior part of the reconstructed ear, we fix the non hair-bearing skin to the depth of the sulcus that generally reaches the mid level of the retroauricular sulcus. The remaining raw area of the mastoid is covered by a separate split-thickness skin graft harvested from the nearby scalp, and a second skin graft covers the temporal fascia (fig. 24). Our results have greatly improved since we have used this technique, and the secondary retraction rate is much lower.

Some of the Final Results Obtained

Figures 25–28 show 4 case studies, who underwent the techniques described in this report.

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Fig. 27. Case 3. Pre- (a) and postoperative (b) pictures. Technique: skin approach type 3a, cartilage framework type III. The reconstruction was performed in 1 stage.

Fig. 28. Case 4. Pre- (a) and postoperative (b) pictures. With the remnants being in an ectopic anterior position, it was better to use a type 3b incision and to thin the lobular skin to cover the inferior part of the framework. Technique: skin approach type 3b, cartilage framework type I, and elevation following our own technique.

Complications

The most severe complication is infection, and the most frequent one is exposure of the cartilage graft secondary to skin necrosis.

Infection In a series of 930 reconstructions in cases of microtia, we observed 6 cases of infection. Here, we are excluding infections occurring after skin necrosis and exposure of the cartilaginous graft. Reviewing our cases of primary infection, we found out that all of them had an auditory canal, and that the responsible bacteria was Pseudomonas.

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Fig. 29. Infection is the most severe complication. a Ectopic remnants with presence of an auditory canal. b The framework has been placed in the ideal location, and the anterior part of the ectopic remnants have been excised. c The entire framework was removed following a severe infection. d The reconstruction was started again from scratch. e Framework type I sculpted from rib cartilage (segments harvested on the right side of the thorax). f Final result after the second reconstruction.

We have never observed a primary infection of a microtic ear without an auditory canal. That is the reason why it is essential to avoid infection in presence of an auditory canal, to clean the canal preoperatively, to perform a bacteriologic study and prescribe antibiotic drops if necessary. In cases of infection, despite attempts to save the cartilage graft using local and systemic l antibiotherapy, resorption of the cartilage will occur. In most of the cases, the resorbed contours will have to be reproduced, which means that more rib cartilage will have to be harvested (fig 29).

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Fig. 30. Exposure is the most frequent complication: a Skin necrosis at the tip of the posterior skin flap after a low type 2 skin approach. b Spontaneous healing in process. c Complete healing after a few weeks.

Fig. 31. Coverage of exposed cartilage on the helix. a Type 2 skin approach. b Some excessive skin tension should have been suspected. c Skin approach allowing the use of a random fascial flap. d Coverage of the exposed cartilage with the fascial flap. e Split skin graft taken from the scalp and covers the fascia. f Result before elevation of the ear. 48

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Fig. 32. Temporal fascial flap in a case of large skin necrosis. a Type 2 skin approach and type I framework to correct microtia on a 55-year-old male. b No evidence of insufficient skin blood supply at the end of the surgery. c Large area of skin necrosis with exposure of the cartilage d Use of an axial temporal fascia flap to save the situation. e Swelling of the flap covered with a split-thickness skin graft 5 days after surgery. f Final result 1 year after elevation of the reconstructed ear.

Exposure A small exposure, i.e. no more than 2 or 3 mm, may heal with local treatment (antibiotic ointment) and careful wound care (fig. 30). Nevertheless, when it is located on the helix, it is usually necessary to cover the exposed cartilage using a small fascia flap (random or axial), covered with a skin split-thickness skin graft harvested from the scalp (fig. 31). In larger exposures, it will be necessary to use an axial temporal fascial flap to save the cartilage (fig. 32).

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Fig. 33. a Very good result. b Good result. c Medium result. d Poor result.

When performing ear reconstruction in cases of microtia, it is essential to correctly analyze the malformation. Keeping in mind the different types of skin approach, the different types of possible frameworks and the principles of the reconstruction will permit logical and productive surgical planning. In this way, complications will naturally be avoided; however, if they occur, saving the situation is part of the learning curve.

Evaluation

To give an appreciation of the results obtained in a large series, we have categorized the last 820 consecutive cases (from January 2003 to April 2009) as ‘very good’, ‘good’, ‘average’ or ‘poor’ (fig. 33). Of these cases, we found: 34% had a very good result,

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49.8% had a good result, 12.5% had an average result and 2.9% had a poor result. Please note that we did not include the management of cases that needed individualized approaches (severe facial asymmetry, low hair line, ectopic remnants, bilateral cases, and secondary cases) in this analysis.

Conclusion

Having performed a large number of ear reconstructions (1,520 cases), including trauma and partial reconstruction, I am convinced that good results obtained with autologous rib cartilage are by far superior to those seen when using a synthetic material or a prosthesis. This requires the surgeon to: understand the tridimensional architecture of the ear, train in carving frameworks before performing surgery, and learn the principles and guidelines for mastering skin and soft tissues. All these requirements greater levels of commitment than those required to perform only the occasional ear reconstruction.

Acknowledgment I would like to thank Alexandre Marchac for his help during the revision of the manuscript.

References 1 Tessier P, Kawamoto H, Matthews D, Posnick J, Raulo Y, Tulasne JF, Wolfe SA: Taking long rib grafts for facial reconstruction – tools and techniques. III. A 2900-case experience in maxillofacial and craniofacial surgery. Plast Reconstr Surg 2005;116:38S– 46S. 2 Firmin F: La reconstruction du pavillon auriculaire en cas de microtie. Rev Laryngol 1997;118:11–16. 3 Firmin F: Reconstruccion del pabellon auricular; in Lopez-Cedrun JL (ed): Cirugia Reconstructiva y Estética del Tercio Medio Facial. Madrid, Aran, 2005, p 365. 4 Firmin F: La reconstruction auriculaire en cas de microtie. Principes, methodes et classification. Ann Chir Plast Esthet 2001;46:447–466. 5 Nagata S: Modification of the stages in total reconstruction of the auricle. Part I. Grafting the threedimensional costal cartilage framework for lobule-type microtia. Plastic Reconstr Surg 1994;93: 221–230, discussion 267–268.

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6 Nagata S: Modification of the stages in total reconstruction of the auricle. Part II. Grafting the threedimensional costal cartilage framework for concha-type microtia. Plast Reconstr Surg 1994;93: 231–242, discussion 267–268. 7 Nagata S: Modification of the stages in total reconstruction of the auricle. Part III. Grafting the threedimensional costal cartilage framework for small concha-type microtia. Plast Reconstr Surg 1994;93: 243–253, discussion 267–268. 8 Brent B: The versatile cartilage autograft: current trends in clinical transplantation. Clin Plast Surg 1979;6:163–180. 9 Brent B: Technical advances in ear reconstruction with autogenous rib cartilage grafts: personal experience with 1200 cases. Plast Reconstr Surg 1999;104: 319–334, discussion 335–338. 10 Firmin F, Sanger C, O’Toole G: Ear reconstruction following severe complications of otoplasty. J Plast Reconstr Aesthet Surg 2008;61(suppl 1):S13–S20.

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11 Firmin F: Reconstruction auriculaire en cas de microtie: La technique de Brent et la technique de Nagata. J Fr Otorhinolaryngol Audiophonol Chir Maxillofac 1996;31:271–331. 12 Firmin F: Intérêt de l’expansion tissulaire dans la reconstruction totale du pavillon de l’oreille. Ann Chir Plast Esthet 1996;41:495–502. 13 Firmin F: Microtie: reconstruction par la technique de Brent. Ann Chir Plast Esthet 1992;37:119–131. 14 Romo T, Presti PM, Yalamanchili HR: Medpor alternative for microtia repair. Facial Plast Surg Clin North Am 2006;14:129–136. 15 Matsunag T: Follow-up study of reconstructed auricle in microtia: comparison of the results of the rib cartilage framework and the silicone rubber framework methods. Auris Nasus Larynx 1989;16:75–88. 16 Romo T: Reconstruction of congenital microtiaatresia: outcomes with the Medpor/bone-anchored hearing aid-approach. Ann Plast Surg 2009;62:384– 389. 17 Helling ER: Endoscope-assisted temporoparietal fascia harvest for auricular reconstruction. Plast Rec Surg 2008;121:1598–1605.

18 Reinisch JF: Microtia reconstruction using a polyethylene: an eight year surgical experience. Proceedings 78th Annu Meet Am Assoc Plast Surg, Colorado Springs, 1999. 19 Firmin F, Raphaël B: Rapport du XXXIIIème Congrès de la Société Française de Chirurgie Plastique Reconstructrice et Esthétique, Paris, 1988. 20 Firmin F, Guichard S: La microtie dans la dysplasie oto-mandibulaire. Ann Chir Plast Esthet 2001;46: 467–477. 21 Guichard S, Diner PA, Arnaud E, Firmin F: Conclusion du rapport: planification du traitement des dysostoses oto-mandibulaires. Ann Chir Plast Esthet 2001;46:575–576. 22 Brent B: Experience with the temporoparietal fascial free flap. Plast Reconstr Surg 1985;76:177–188. 23 Brent B, Byrd HS: Secondary ear reconstruction with cartilage grafts covered by axial, random, and free flaps of temporoparietal fascia. Plast Reconstr Surg 1983;72:141–152.

F. Firmin Clinique Bizet 21, Rue Georges Bizet FR–75116 Paris (France) Tel. +33 1 4069 350, Fax +33 1 5357 8766, E-Mail [email protected]

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Staudenmaier R (ed): Aesthetics and Functionality in Ear Reconstruction. Adv Otorhinolaryngol. Basel, Karger, 2010, vol 68, pp 53–64

Ear Reconstruction with Porous Polyethylene Implants Alexander Berghausa ⭈ Klaus Steltera ⭈ Andreas Naumannb ⭈ John Martin Hempela a Klinikum Grosshadern, Ludwig-Maximilians-Universität München, Munich, und bKlinik und Poliklinik für HalsNasen-Ohrenheilkunde Universitätsklinikum des Saarlandes, Homburg/Saar, Germany

Abstract This article describes a surgical technique using porous polyethylene as the framework material for ear reconstruction. In comparison to the use of rib cartilage, porous polyethylene – first described by Berghaus in 1982 – provides better definition and projection as well as congruency with the opposite side. Hospitalization time is significantly shorter. There are less surgical interventions than with traditional microtia operations that use rib cartilage, and the patient is spared the additional procedure needed to remove the rib cartilage, with all the associated complications as well as the resulting thorax scar. Also, reconstruction can take place at an earlier age, which is advantageous for those concerned. Using porous polyethylene as the frame material, a temporoparietal flap and full-thickness skin cover, we have been able to achieve very convincing results over recent years. Copyright © 2010 S. Karger AG, Basel

History of Ear Reconstruction

A review conducted by Berghaus and Toplak [1], which examined more than 400 publications, 200 authors and 3,300 cases, showed that although auricular reconstruction was performed as early as the 6th century BC, total reconstructions were still considered out of the question in 1830. In 1891, on the other hand, there were already more than 40 different framework materials available for this operation, such as cartilage, bone and alloplastic substances. However, only 8 of these have still been used within the last 20 years, primarily autogenous rib cartilage and alloplastic materials. By 1908, Schmieden [2] had already shaped the auricular framework using rib cartilage. In the English-speaking world, Gillies [3] was one of the first people to perform auricular reconstruction using autologous rib cartilage, in 1920. Allogeneic rib cartilage was also used for a period. However, this material soon proved to be unsuitable because the cartilage was re-absorbed in almost 100% of the cases, although

amazingly this was rarer when crushed allogeneic rib cartilage was used [4]. In particular, Tanzer [5, 6], Brent [7, 8] and Nagata [9] pioneered operative techniques for auricular reconstruction with rib cartilage that are still used today in a modified form. The method published by Tanzer [5, 6] describes a multiple-step process of a total of 4 procedures that utilizes the cartilage of the 6th, 7th and 8th contralateral ribs [10]. Brent [7, 8], as well as Tanzer [5, 6], used a 3- or 4-step technique [7, 8], although the framework of Brent [7, 8] is several millimeters narrower, taking into account the strength of the skin transplant that will rest on it later. The technique introduced by Nagata [9] generally requires only 2 steps to create the ear concha, and takes the cartilage from the ipsilateral side. However, when it became known that even autogenous rib cartilage could be absorbed over time, potentially causing ugly malformations, some surgeons began using alloplastic frameworks instead of biological materials. Thus, materials such as unvulcanized rubber, tantalum wire, acrylic glass, X-ray film, polyamides, silicone, Teflon and polyethylene were used [1]. Details on the use of a silicone framework for auricular reconstruction were published in 1966 by Cronin [11, 12], and the initial results were good. However, studies showed that exposure and infections occurred too frequently for this material to be used as standard [12–14]. For the first time, in 1964 Hermann and Zuehlke [15] described the use of ‘enveloping of the supportive framework’ with cranial periosteum to wrap the framework during auricular reconstruction. In 1976, Fox and Edgerton [16] used the ‘fan-flap’ to protect the implant or the transplant. The intention was to reduce the risk of skin perforation and necrosis by covering the framework with the fascia of the temporal muscle [16]. The ‘fan-flap’ is normally understood as the caudally stemmed strong deep layer of the temporal fascia of the temporal muscle. Since the supply of vessels and nerves of the flap are arranged in a fan-like fashion, it is possible to use the flap in varying sizes. However, the intermediate temporal artery supplies only a little vascularization [17]. In contrast to this, the temporal parietal fascia or aponeurosis, which lies directly beneath the subcutaneous connecting tissue of the hair-bearing skin of the head, is reliably supplied by the superficial temporal artery (the temporal parietal flap, TPF). Because of this good vascularization, the TPF flap has come to be regarded as a stemmed and strong flap in the areas of the head and neck. These characteristics resulted in its usage in covering transplants or implants within the context of total auricular reconstruction. Its elasticity and softness of only 1–2 mm strength means that it is possible to construct an exceptionally fine ear, with all its nuances [18].

Disadvantages of Rib Cartilage Frames

Most professionals prefer to use autogenous rib cartilage when reconstructing the auricle. Nonetheless, rib cartilage does have various disadvantages. Due to the

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somewhat unpredictable behavior of rib cartilage, the esthetic results are often unsatisfactory because it bends out of shape or is re-absorbed [1, 19]. An ear of rib cartilage often shows increasing postoperative weakness in terms of definition, fineness of structure, and quality in comparison to the healthy one. This method also often requires several reconstruction steps, which means that the time required for creating an adequate ear concha increases. Furthermore, removal of rib cartilage is painful with larger transplants, and in cases of insufficient postoperative analgesia there is a considerably increased risk of pneumonia. Severe pain also causes a highly catabolic metabolism that, in turn, produces a risk of delay in wound healing. One must also be cautious of postoperative complications, such as pneumothorax and atelectasis, as well as later thorax deformations and ugly scars at the graft removal sites [1, 19]. In 18 microtia corrections, Ohara et al. [20] observed thorax deformities in more than 64% of the patients under 10 years of age. Re-absorption and the flattening of the implanted rib cartilage is one of the most feared postoperative complications, and occurs in up to 40% of cases [21]. Skin necrosis and skin perforations are also seen when rib cartilage is used. The skin cover – in contrast to the porous polyethylene method – is mainly made of local skin that often leads to hair growth on the new ear concha due to low hairlines. This is cosmetically unpleasant, and is difficult to correct. Sufficient rib cartilage for reconstruction also requires a certain minimum age of the patient. Good long-term results can only be anticipated if the patient is at least 9 or 10 years of age. The attempt to make due with a little bit of cartilage usually leads to unsatisfactory results or a poor projection of the new ear. However, since patients with ear concha malformations are often the target of teasing and suffer the emotional stress that goes with it, it is recommended that surgical correction be undertaken as early as possible, best of all would be prior to kindergarten [21, 22]. Another disadvantage that ought to be mentioned is the progressive calcification of the rib cartilage with increasing age. A growth of about 6% in the third decade of life and up to 45% in the 9th decade of life is probable [23]. Working with the cartilage of older patients therefore becomes increasingly difficult. It is almost impossible in some cases to bend the helix without breaking the cartilage [24].

Porous Polyethylene as Frame Material

In 1982, through experimental studies, the first author (B.A.) recognized that porous polyethylene (available today as Medpor®, Porex Surgical, Newnan, Ga., USA) is a tissue friendly, stable and infection-resistant framework material for use in auricular reconstruction [25]. It is a biocompatible thermoplastic synthetic material that is not prone to infections and has a pore size of 100–400 μm, making it possible for the tissue to infiltrate rapidly (fig. 1). The material can be easily molded and shaped as

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Fig. 1. Porous polyethylene (PE; white masses) after implantation showing ingrowth of healthy fibrous tissue into the pores. Giemsa stain. ×100.

a

b

c

d

e

f

Fig. 2. Case example of microtia: preoperative (a–c) and postoperative (d–f) findings.

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individually needed with the use of a scalpel, a drill, or by heating it during the surgical procedure. Ear reconstruction with polyethylene is indicated in microtia (fig. 2), anotia, and partial or total loss of the pinna due to trauma (fig. 3). A microtia, i.e. a malformed and only rudimentary external ear in its very varying forms, is the result of a developmental anomaly of the first 2 pharyngeal arches. It is often combined with a low hairline, auditory canal stenosis or atresia (a malformation of the middle ear), and changes in the sides of the face [22]. Microtia occurs in approximately 1:7,000 to 1:10,000 births [26]. It has become a surgical priority primarily due to psychosocial pressures and the suffering of the patient [27]. The fact that 90% of patients view their postoperative condition with the reconstructed auricle as a significant improvement over their untreated microtia justifies an extensive surgical procedure [22]. In children with microtia or anotia, we perform the operation around the age of 6 years, usually ahead of entering elementary school. There is no age limitation for ear reconstruction with polyethylene. The oldest patient in whom we have performed ear reconstruction with polyethylene was a 70-year-old woman with microtia.

Technical Preparations

Photos are taken prior to the surgical procedure for the purpose of documentation. In order to create aesthetically pleasing results in terms of the size and position of the ear concha, the contours of ear, nose and eyes (eyebrow and lateral canthus) of the healthy side are drawn using a water-resistant lithographic crayon on a transparent silicone template and then transferred as a mirror image onto the contralateral side. An aid to help orientate the new location of the ear is that the helix attachment (otobasion superior) is almost at the same height as the lateral canthus. The superaurale is in a horizontal line with the top of the eyebrow, and the lobulus is on the same level as the tip of the nose. The subaurale (lowest point of the lobulus) is in line with the spina nasalis. One other point of orientation is the line of the nasal dorsum that runs approximately parallel to the longitudinal axis of the ear, but which deviates from this by about 8° (fig. 4). Also, it is helpful to measure the distance of the lateral orbital wall to the tip of the helix, and total length of the ear. A 3-dimensional model of the healthy ear is an additional planning aid. This model can be obtained by making an impression of the healthy ear as a template. A new model is then created out of the template with plastic polymer, and sterilized for availability during the operation. At the age of 6 years, the size of the ear is about 85% of the adult ear. In young children, we consider this fact in reconstructing the ear, using the anthropometric data of Weerda and Siegert [28]. In cases of pronounced facial deformities, the positioning of the new ear concha does not have to follow guidelines that are too strict; instead, it must be adapted to the asymmetrical proportions of the face.

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a

b

c

d

e

f

Fig. 3. Case example of traumatic ear deformity after piercing: preoperative (a–c) and postoperative findings (d–f).

Axis of ear

Nasal dorsum

A B

Fig. 4. Planning the new ear position. The distance of the lateral orbital rim to the upper helical rim (A) and the length of the ear (B) are marked. The axis of new ear corresponds to nasal dorsal line (±8°).

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Fig. 5. Incision lines, including Z-plasty for correction of ear lobe position, hairless local skin flap, and incision for harvesting of TPF.

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Prior to the start of the procedure, Doppler sonography is used to locate and mark the course of the temporal artery of the affected side. The course of the planned cut is then drawn in. The course of the incision includes (fig. 5): • cutting around the local skin flap below the hairline, which will later cover the helix of the new ear concha (‘helix’ flap); • a modified Z-shaped incision for the transfer of the unphysiologically positioned earlobe; • the Y-shaped incision that gives access to the TPF.

Surgical Procedure

The temporal parietal fascia or aponeurosis (i.e. the TPF), which lies directly beneath the subcutaneous connecting tissue of the hair-bearing skin of the head, is reliably supplied by the superficial temporal artery. The TPF is a stemmed and strong flap of 1–2 mm strength. Its elasticity and softness makes this flap optimal for the construction of an exceptionally fine ear with all its nuances. A thin flap of scalp skin is lifted by means of the temporal modified Y-shaped cut, making sure that the roots of the hair are not damaged and the temporal fascial aponeurosis with the superficial temporal artery (i.e. the TPF) is displayed (fig. 6). This type of preparation, which is preferably performed using magnifying eyeglasses or a microscope, leaves a small layer of fat on the scalp, just enough so that the hair roots are still recognizable. The TPF should be as thin as possible, but the artery and its vein must not be damaged. In order to have sufficient material to mantle the ear framework, it is advisable to define the TPF as an area of about 12 × 10 cm in microtia or anotia (fig. 7). An option is to lift the TPF endoscopically, although this technique takes more time and effort. The authors recommend preparing the scalp flap with a scalpel, and not with an electrosurgical needle. The Y-shaped cut is lengthened into the ‘helix’ flap and the modified Z-shaped incision. While lifting the local ‘helix’ flap, ear cartilage rudiments are resected. They are stored in physiological saline solution, and later used to reconstruct the tragus. Usually, the base of the ‘helix’ flap is 1/3 to 1/4 of the total length of the whole flap. The distal 2/3 of the flap are thinned, and all of the fat is removed. In the next step, the site where the concha and the distal part of the external ear canal are located is prepared, resecting as much tissue as possible and keeping the location of the temporal artery in mind.

Completing the Implant

The polyethylene framework is put together intraoperatively from 2 basic elements (helical rim and ear base). The 2 parts are connected to each other by heating the synthetic

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Temporal fascia TPF

Fig. 6. Raising the TPF.

a

M. temporalis

Fig. 7. TPF with the superficial temporal artery.

b

Fig. 8. a, b Porous polyethylene implant, consisting of helical rim and ear base (courtesy of Porex Surgical).

material by spot-welding with a cautery device or by suturing (fig. 8). In order that the contours match each other to the greatest possible extent, if possible, a 3-dimensional mirror impression of the healthy ear is used as both an orientation aid and as a working example. The form of the implant is corrected using the scalpel or a slow-running drill until it precisely meets the requirements. In the reconstruction of traumatic ear defects, the polyethylene framework must be shaped in such a way that there is a smooth junction between the autologous cartilage and the alloplastic material. The tragus is usually shaped from rudimentary cartilage in a wave-like manner. The cartilage can be sutured to the polyethylene framework with a long-lasting

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Fig. 9. Encasing the implant with the TPF.

resorbable suture. In anotia, a composite graft of the contralateral ear can be used for tragus reconstruction [1]. Soaking the implant in an antibiotic solution serves to prevent early infections. To reach all the pores of the implant, a large injection syringe filled with antibiotic solution can be used to set the framework under suction by pulling on the plunger.

Inserting the Implant

The Medpor framework and the cartilage for the tragus is now inserted into its determined position. It is completely enveloped by the TPF and fixed into the desired position with a suture, and can be adapted to any existing rudimentary ear gristle that might be left (fig. 9). One or two relatively strong sutures pulled through the synthetic material using long-term absorbable material will hold the implant in the ideal position once it is located. The TPF flap that sheaths the implant becomes a casing that lies close to it as a result of the short-term re-absorbable sutures. Before closing the wound, a continuous suction drain is placed under the implant with the fascial flap and another one is placed under the scalp at the site where the fascia has been lifted. These drain the wound secretions for about 7 postoperative days and ensure tight contact between skin, fascial flaps and framework.

Covering the New Ear Concha with Skin

The skin covering of the newly formed ventral side of the ear comes from the local flap (‘helix’ flap) and from the full-thickness skin of the postauricular surface of

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the contralateral ear. A rather large uniform transplant of skin can be obtained from the back of the healthy ear concha and the mastoid skin. When cutting this, it must be kept in mind that a hairless area must be taken, and that the incisions (with later scars) are not visible from the front and side. The ventral cover of the tragus is created by moving a flap of the skin of the cheek in a dorsal direction, similarly to the way it is done in a face lift, or a 2-wing flap is circumcised in front of the ear with its base on the front edge of the planned entry to the auditory canal. Both wings of the flap are folded back against each other and stabilized with a piece of cartilage. The post-auricular skin defects remaining on both sides are covered with fullthickness grafts taken from the groin or abdominal areas. We had the best results when we removed this skin in 1 spindle-shaped piece of about 10 × 3 cm. The location from which this was removed lies within the ‘bikini zone’ and outside of the pubic hair, between the midline and the spina iliaca anterior superior. The transplant must be considerably thinned with all of the fat removed. The abdominal skin is then divided into 2 pieces, each adequate in size to cover the postauricular defects on both ears.

Bandages

Once the wound is sutured and drainage fixed into place, salve is spread on the reconstructed ear and a D-shaped ring of foam-like material is placed around the ear. This is filled with a 2-component silicone foam (Cavi-Care®, Smith & Nephew, London, UK), which is fluid at first and then polymerizes when exposed to the air after being mixed. It does not exert excessive pressure on the new ear, but it holds the skin adequately to the fascia flap. This is then followed by a bandage that fixes everything into place. The full-thickness graft on the back of the healthy ear concha is also fitted with a foam foil (Reston®, 3M, St. Paul, Minn., USA), which is sewn on and remains in place for about 5 days. The wound on the abdomen from which the graft was taken is taped after suture.

Complications

The possible complications of this operation include a mostly temporary, in very rare cases permanent, hair loss on the scalp in the area of the cut needed to harvest the TPF flap. For prevention, especially in skinny young children, a thin strip of skin may be cut out or the procedure should be done endoscopically. Very rare complications include: the danger of a partial, or in extremely rare cases total, extrusion of

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the implant through the skin cover; the negative cosmetic results arising from the development of any scars in the area (also at the sites where skin grafts were taken from); the pull of any scars and unwanted changes in the original position of the ear concha.

Acknowledgement The authors would like to thank Dr. Karin Graser for her support in compiling the bibliography.

References 1 Berghaus A, Toplak F: Surgical concepts for reconstruction of the auricle: history and current state of the art. Arch Otolaryngol Head Neck Surg 1986;112: 388–397. 2 Schmieden V: Der Plastische Einsatz von traumatischen Defekten der Ohrmuschel. Berl Klin Wschr 1908;31:1433–1435. 3 Gillies HD: Plastic Surgery of the Face. Oxford, Oxford University Press, 1920, pp 381–387. 4 Berghaus A, Axhausen M, Handrock M: Porous synthetic materials in external ear reconstruction. Laryngol Rhinol Otol 1983;62:320–327. 5 Tanzer RC: Total reconstruction of the auricle: the evolution of a plan of treatment. Plast Reconstr Surg 1971;47:523–533. 6 Tanzer RC: Total reconstruction of the auricle: a 10-year report. Plast Reconstr Surg 1967;40:547– 550. 7 Brent B: The versatile cartilage autograft: current trends in clinical transplantation. Clin Plast Surg 1979;6:163–180. 8 Brent B: Technical advances in ear reconstruction with autogenous rib cartilage grafts: personal experience with 1200 cases. Plast Reconstr Surg 1999; 104:319–334. 9 Nagata S: Total auricular reconstruction with a three-dimensional costal cartilage framework. Ann Chir Plast Esthet 1995;40:371–399. 10 Tanzer RC: Total reconstruction of the auricle: a 10-year report. Plast Reconstr Surg 1967;40:547– 550. 11 Cronin TD: Use of a Silastic frame for total and subtotal reconstruction of the external ear: preliminary report. Plast Reconstr Surg 1966;37:399–405. 12 Cronin TD, Greenberg RL, Brauer RO: Follow-up study of Silastic frame for reconstruction of external ear. Plast Reconstr Surg 1968;42:522–529.

13 Ohmori S, Sekiguchi H: Follow-up study of the reconstruction of microtia using Silastic frame. Aesthetic Plast Surg 1984;8:1–6. 14 Wray RC, Hoopes JE: Silastic frameworks in total reconstruction of the auricle. Br J Plast Surg 1973; 26:296–297. 15 Herrmann A, Zuehlke D: Periosteum as a substitute for the perichondrium in reconstruction of the external ear. Langenbecks Arch Klin Chir Ver Dtsch Z Chir 1964;306:59–65. 16 Fox JW, Edgerton MT: The fan flap: an adjunct to ear reconstruction. Plast Reconstr Surg 1976;58:663– 667. 17 Cheney ML, Megerian CA, Brown MT, McKenna MJ, Nadol JB: The use of the temporoparietal fascial flap in temporal bone reconstruction. Am J Otol 1996;17:137–142. 18 Reinisch JF, Lewin S: Ear reconstruction using a porous polyethylene framework and temporoparietal fascia flap. Facial Plast Surg 2009;25:181– 189. 19 Walton RL, Beahm EK: Auricular reconstruction for microtia. Part II. Surgical techniques. Plast Reconstr Surg 2002;110:234–249. 20 Ohara K, Nakamura K, Ohta E: Chest wall deformities and thoracic scoliosis after costal cartilage graft harvesting. Plast Reconstr Surg 1997;99:1030– 1036. 21 Fox JW, Edgerton MT: The fan flap: an adjunct to ear reconstruction. Plast Reconstr Surg 1976;58:663– 667. 22 Siegert R, Knolker U, Konrad E: Psychosocial aspects in total external ear reconstruction in patients with severe microtia. Laryngorhinootologie 1997;76:155–161.

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23 Mori H, Tanaka K, Umeda T, Hata Y: Ear reconstruction in elderly patients: a two-part helix method in a framework. Br J Plast Surg 2002;55:589– 591. 24 Brent B: The pediatrician’s role in caring for patients with congenital microtia and atresia. Pediatr Ann 1999;28:374–383. 25 Berghaus A: Porous polyethylene in reconstructive head and neck surgery. Arch Otolaryngol 1985;111: 154–160.

26 Jahrsdoerfer RA, Yeakley JW, Aguilar EA, Cole RR, Gray LC: Grading system for the selection of patients with congenital aural atresia. Am J Otol 1992;13:6–12. 27 Hempel JM, Krause E: Treatment of hearing impairment in children. MMW Fortschr Med 2006;148:30– 33. 28 Siegert R, Weerda H, Remmert S: Embryology and surgical anatomy of the auricle. Facial Plast Surg 1994;10:232–243.

Prof. Alexander Berghaus, Direktor der Klinik für Hals-, Nasen-, Ohrenheilkunde Ludwig-Maximilians-Universität Munich, Klinikum Grosshadern Marchioninistrasse 15 DE–81377 Munich (Germany) Tel. +49 89 7095 2990, Fax +49 89 7095 8891, E-Mail [email protected]

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Staudenmaier R (ed): Aesthetics and Functionality in Ear Reconstruction. Adv Otorhinolaryngol. Basel, Karger, 2010, vol 68, pp 65–80

Auricular Prostheses Philipp A. Federspil Department of Oto-Rhino-Laryngology, University Hospital Heidelberg, Heidelberg, Germany

Abstract An auricular prosthesis is an artificial substitute for the auricle; the term epithesis is used synonymously. A myriad of materials have been used in the long history of anaplastology. However, the breakthrough came with the introduction of modern silicones and their colorings. While there are still indications for noninvasive methods of retention, such as medical adhesives, the best and most reliable method of fixation is bone anchorage. Long-lasting osseointegration with reaction-free skin penetration can be achieved with titanium implants. The first system used extraorally was the Brånemark flange fixture. Later, different solitary titanium implants were introduced, such as the ITI system. A different strategy used the titanium grids (Epitec®) or plates (Epiplating®) derived from osteosynthesis systems. These systems are fixed subperiostally with several bone screws, and are therefore also labeled as grouped implants. With these modern developments, secure retention can also be achieved in unfavorable anatomical situations. Advantages of implant-retained auricular prostheses include: optimal camouflage, predictable cosmetic results, fast rehabilitation, no donor site morbidity and early detection of tumor recurrence. Depending on the clinical setting, prosthetic rehabilitation can be a viable treatment option, and more than just an alternative to plastic reconCopyright © 2010 S. Karger AG, Basel structive surgery.

Definition and a Brief History of Craniofacial Prosthetics

A craniofacial prosthesis is an artificial substitute for parts of the face and adjacent structures that have been lost. In German- and Scandinavian-speaking areas, the word episthesis is used synonymously. The art of making craniofacial prostheses is also called anaplastology. Early attempts at maintaining the normal body contour occurred in the 2nd Egyptian dynasty around 3000 BC [1]. The first patient proven to have a craniofacial prosthesis was the Danish astronomer Tycho Brahe (1546–1601), who lost most of his nasal dorsum in a duel. He was treated with a metal prosthesis made out of gold or copper covered with oil paint to match his skin [1]. The French surgeon Ambroise Paré (1510–1590) introduced the use of extraoral prostheses, and deserves recognition as the true founder of the field of maxillofacial prosthetics. He designed an auricular prosthesis made of leather and held in place by a flexible flat spring which was hidden

Fig. 1. Patient with an implant-retained ear prosthesis made of silicone. Note the fine edges. Courtesy of Mathias Schneider, Anaplastologist, Zweibrücken, Germany.

Fig. 2. The ear prosthesis was made to match the lifestyle of this patient. Courtesy of Ms. Daniela Hering, Anaplastologist, Genthin, Germany; Surgeon: Annett Sandner, M.D., Halle, Germany.

under the patient’s hair. Obviously, the major drawbacks for rehabilitation with auricular prostheses were the inadequate materials and the lack of reliable methods of retention [2].

Materials for Auricular Prostheses Virtually all available materials, e.g. porcelain, wax, rubber and paper maché, have been tried in the fabrication of craniofacial prostheses. A major step forward was the introduction of methyl methacrylate. Its disadvantage, however, was its hardness. Still, it is a long-lasting material that may be colored, and as such has retained its indication in areas where medical care cannot be given on a regular basis. The breakthrough for auricular prostheses came with the introduction of the modern silicones and their colorings (fig. 1). Silicone is flexible, and it adapts to the body temperature. Hair and pigments can be introduced into the material. Its edges can be made thin enough to become transparent, in such a way that the prosthesis blends into the face. This enhances the camouflage even more. Moreover, the prosthesis can be made according to the patient’s wishes in order to fit his/her lifestyle (fig. 2). Although, usually complete prostheses are manufactured, it is also possible to fit partial prostheses (fig. 3).

Methods of Retention for Auricular Prostheses Generally, craniofacial prostheses can be retained in 4 ways: • Anatomical anchorage: This may work in the orbit, but the ear canal (if present) never allows reliable fixation. • Mechanical anchorage: Various mechanical devices, such as head springs, have been tried with little success. Spectacle frames do not provide enough strength to keep the prostheses in place unless otherwise aided.

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a

b

c

Fig. 3. a This lady has a partial auricular defect after failed rib cartilage reconstruction following hemangioma treatment. The site of skin penetration is reaction-free 10 years after implantation of 2 Brånemark implants. b Close-up of an implant-retained partial auricular prosthesis (Mathias Schneider, anaplastologist, Zweibrücken, Germany). c Oblique view.

Fig. 4. Ten-year-old girl with bilateral anotia. a Scar formation is seen as a result of failed distraction osteogenesis. A bilateral bone-anchored hearing aid was fitted. b The silicone ear prosthesis is retained by medical adhesives.

a

b

• Chemical anchorage: Medical-grade adhesives may provide satisfactory fixation (fig. 4). However, retention is degraded over time by perspiration and other environmental factors. Furthermore, dermal irritation from long-term contact or allergic reaction are not uncommon with the use of adhesives. • Surgical anchorage: Surgical techniques to create loops or pockets by various flaps in order to retain the auricular prosthesis have been described [3]. Today, surgical anchorage is in fact bone anchorage by titanium implants [2]. Bone anchorage provided a major breakthrough for craniofacial prostheses because it guaranteed secure and reliable retention. The first time titanium implants were used percutaneously outside the oral cavity was in 1977 by Anders Tjellström for a bone-anchored

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hearing aid (BAHA) [4]. Two years later, in 1979, the first bone-anchored auricular prosthesis was provided for a patient [5]. Bone anchorage has various advantages over the other methods of retention [6]: • Enhanced and reliable retention in spite of adverse defect anatomy and size. • Retention is rarely influenced by environmental factors. • Facilitated insertion of the prosthesis into the proper position by the patient himself. • Convenience is improved by the absence of adhesives and less skin occlusion. • The functional life of implant-retained prostheses is extended, as marginal degradation due to the daily application and removal of adhesives is eliminated. The auricular prosthesis may be coupled to the implants either by the classical clip-bar system or by magnets. The bar construction almost always requires parallel implant axes, otherwise it is virtually impossible to produce a bar that does not put strain on the implants [7]. However, retentive clips may be adjusted in strength to individual needs. While magnets are easier to clean [8], they have to be removed before MRI.

Osseointegration – Bone Anchorage

In the 1950s, Per-Ingvar Brånemark discovered the tremendous biocompatibility of titanium in bone and coined the expression ‘osseointegration’ [9]. At first, osseointegration was defined as direct contact to bone as examined by light microscopy. However, it was found that the bone contact area in osseointegrated implants was only 70–80% on average [10]. On electron microscopy, an amorphous gap of 20–500 nm is visible. The clinical definition given by Zarb and Albrektsson [11] still holds true today: ‘A process whereby clinically asymptomatic rigid fixation of alloplastic materials is achieved, and maintained, in bone during functional loading.’ Several factors influence the establishment of osseointegration [12]: • biocompatibility; • implant design; • implant surface; • condition of recipient area; • surgical technique; • implant loading.

Implant Systems

The extraoral implant systems (fig. 5) are derived from dental implants. The first system was the Brånemark system, which is a solitary screw-type implant made out of commercially pure titanium with a minimally rough surface. The American Society for Testing and Materials (ASTM) gave the specification F-67 for unalloyed titanium as a surgical implant of grades 1–4. While most osteosynthesis plates are produced according to ASTM F-67, various titanium alloys, such as the very popular alloy titanium 6-aluminium 4-vanadium (Ti6Al4V), are used in orthopedic titanium

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Fig. 5. Different extraoral implant systems: Epitec® (left), Brånemark Vistafix® system (back left), ITI® system (back right), Epiplating® system (front). Titanium bone screws of 4, 5.5 and 7 mm length.

implants that have to bear more strain. Ti6Al4V bone screws have been shown to have a bone contact area comparable to unalloyed titanium implants in animal experiments [13] and retrieved human specimens [14]. While there is a great diversity of implant systems and manufacturers for dental implants, there are only few systems available for craniofacial prostheses. In order to group the available systems, the terms ‘solitary’ and ‘grouped’ implants have been introduced.

Solitary Implant Systems Brånemark System As described previously, the Brånemark system was the first system used extraorally, and most of the experience gathered worldwide has been with this system [15]. The self-tapping screws (flange fixture) are 3.75 mm in diameter and come in 2 sizes: 3 and 4 mm in length. There are also flangeless fixtures available for the use in the midface. The system is currently marketed under the name Vistafix® by Cochlear. ITI System The ITI system consists of self-tapping screws of 3.3 mm diameter. They come either with a flange at lengths of 2.5 or 4 mm, or without a flange at lengths of 3.5 or 5 mm. The extraoral system has a roughened surface, the so-called SLA surface (sandblasted, large grit, acid-etched). Other Solitary Systems Other currently marketed solitary systems include the Ankylos® system by DentsplyFriadent, and the grade-4 titanium implants by Southern Implants. Some systems, such as the IMZ® system by Friadent and the Epiplant® system by Mathys, are no longer on the market.

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Grouped Implant Systems In 1956, Köle and Wirth [16] described subperiostal frame implants made of Wisil®, a cobalt-chromium alloy, for the fixation of craniofacial prostheses. These frame implants were adapted to the bone surface without actually being anchored into the bone. The prostheses were attached to percutaneous parts of the frame implant. Two patients have been rehabilitated with an auricular and a nasal prosthesis, respectively. Both implants are reported to have healed well, without adverse reactions 8 years later [17]. However, the use of such frame implants on the mandibula for dental rehabilitation was less successful [17]. Both systems described in this section consist of subperiostally placed plate-like titanium implants. However, these implants are fixed to the bone with several titanium bone screws according to the osteosynthesis technique. Thereby, the loading forces are spread to multiple, or grouped, bone screws. This allows implantation in areas with anatomically unfavorable bony resources, e.g. the nasal region, or in the ideally pneumatized mastoid. The percutaneous connection is not necessarily at the bone fixture, but may be at the level of the plate. Epitec® System Mostafa Farmand [18] is credited with the development of the Epitec® system with Leibinger in 1991, which represented a great leap in progress for implantology of craniofacial prostheses. The system consists of a titanium grid with 16 tapped holes, the so-called 3D carrier plate, which is fixed to the bone by titanium bone screws of the 2.0-mm system in various lengths. The connecting arms of the grid are approximately 1 mm in width. Soft tissue reduction is not generally advocated with this system. Epiplating® System The Epiplating® system was developed in 2000 by Medicon in collaboration with P. Federspil, P.A. Federspil and M. Schneider [19]. It is an adaptation of the 2.0 titanium miniplate system used in craniofacial trauma care to the needs of anaplastology. The plates are made of grade-2 unalloyed titanium according to ASTM F-67, i.e. commercially pure titanium. The bone screws are made of Ti6Al4V according to ASTM F-136. The system comes with specialized plates for different anatomical regions. They are 1 mm in height and 2 mm in width, and therefore somewhat more resistant to strain by loading and less vulnerable to loosening. The tapped holes for percutaneous abutments are 2 mm in height; thus, providing good retention of the elements screwed in. Additionally, there is a plate available that can be connected with the BAHA snapcoupling abutment [19, 20]. The Epiplating system has also been employed by other groups with success [20–22].

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≥ 1.5 cm

2 cm

2 cm

Fig. 6. The ideal position for retention elements is marked, with a distance to the center of the outer ear canal of 2 cm. The distance inbetween the implants should be at least 1.5 cm.

Surgical Technique

The basic principles of implant surgery were all elaborated in the original Brånemark technique. The surgery consists of 2 steps: step 1 is the placement of the implant, and step 2 is the soft tissue reduction and percutaneous connection. Originally, the 2 procedures were separated by a healing period of 3 months with the implant unloaded. Steps 1 and 2 may be combined to a single-stage procedure in an adult patient with bone width of more than 3 mm and no history of radiotherapy. Then, the healing period may be reduced to 6 weeks. Minimizing trauma to the bone is of paramount importance, and can be accomplished by: • use of a sharp burr; • low drilling speed (1,500–2,000 rpm); • ample cooling with saline solution.

Positioning the Implants The area of placement has to be chosen according to the needs of the anaplastologist, regardless of the implant system in use, and it is wise to discuss each case in a team with the anaplastologist. Usually, 2 percutaneous abutments are sufficient for retention and proper bar construction. However, in some instances the anaplastologist may wish to use 3 magnets in an individual patient. The ideal position of the percutaneous connection is approximately 20 mm from the center of the outer ear canal or, in an atretic ear, the anticipated opening (fig. 6). Classically, the positions are at 8.00 and 10.30 on the right side (when imaging a clock face on the patient). On the left side, this corresponds to 4.00 and 1.30. However, in our experience, it is preferable to place the lower implant at 9.00 or 3.00, respectively. In all cases, the minimum distance between abutments or magnets should be 15 mm. The area of percutaneous abutments reflects the anti-helix of the prostheses.

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Surgical Technique with Solitary Implant Systems For solitary implant systems, special instruments are required. Palpating while drilling with a cutting burr allows control of the bone width and detection of the dura mater. In the case of implant surgery for an auricular prosthesis, the burr is more likely to meet a mastoid air cell. In an ideally pneumatized mastoid, it might be difficult to find enough bone width at the desired implantation site. The burr hole is then widened by a spiral drill. The self-tapping titanium fixture comes pre-mounted, and is inserted with the machine at low speed under torque control (10–45 Ncm). The titanium fixture should only be handled with titanium instruments in order to avoid contamination. The longer fixture is preferred. At this point, the inner threads of the implant are now secured by a cover screw, and the wound is closed, or the procedure is continued with step 2. Radical soft tissue reduction is vital. The dermatome has proved to be a valuable tool in achieving a split-thickness skin flap with a hairless area. The skin is removed by a biopsy punch over the implant, and the skin penetrating abutment is inserted under torque control at 20 Ncm. An abutment clamp provides counter torque in order not to move the underlying implant. Ointment-soaked ribbon gauze is wrapped around the abutment under a healing cap in order to avoid the formation of a hematoma (fig. 7).

Surgical Technique with Grouped Implant Systems Osteosynthesis instruments are used for grouped implant systems, with the addition of a few special tools. The bony surface is exposed while preserving a generous periosteal flap (fig. 8–11). In the Epitec system, the grid is cut to meet the individual’s needs. In the Epiplating system, the auricular plate with 2 threaded holes or several universal plates may be used. Moreover, the auricular plate may be cut to meet special anatomical situations. Recently, a new type of auricular plate with 3 threaded holes has become available, which is designed to be equipped with 3 magnets. The plate is bent to meet the bony contour. Before doing so, the threads are secured by cover screws in order to avoid any distortion that would have an impact upon the mounting of the abutments. The plate is held at the desired position, and a hole for the bone screw is created by a 1.6-mm spiral drill at low speed under ample cooling. Care is taken while inserting the self-tapping bone screw in order to minimize trauma and strain on the bone. A minimum of 3 bone screws are used depending on the individual plate. Soft tissue reduction may be done in a 1-stage procedure if care is taken to preserve a viable periosteal flap. However, it is easier and safer when performed in a 2-stage procedure. Percutaneous abutments (base posts) are inserted. Magnets may be applied to the abutments or inserted directly into the plate. Unlike the solitary implants, the plate systems are resistant to torque with abutment insertion.

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b

c

d

Fig. 7. Surgical steps with the Brånemark Vistafix system in a microtia patient (second stage procedure). a A split-thickness skin flap is created with the use of a dermatome. b Soft tissue reduction is essential. c The skin is folded back, and the abutments connected to the implants. The ear remnant is removed in order to create space for the prosthesis. d Hematoma formation is prevented by compression using ointment-soaked ribbon gauze.

Results with Implants for Auricular Prostheses The largest experience has been gathered with the Brånemark system. The best results with extraoral implantation can be obtained in the mastoid. The success rates with regard to implant survival ranges from 95% [23] to 99% [24] in the non-irradiated temporal bone. Parel and Tjellström [25] reported a success rate of 98.3%. Wolfaardt et al. [26] had a 98.9% success rate in the same region. In our own institution, the success rate is 97.7% for Brånemark implants for auricular prostheses [27]. Farmand [28] reported a survival rate of 87.5% for 32 Epitec grids at all sites; however, the failures dated from the first surgeries. In our own institution, the success rate is 98.8% for 87 Epiplating implants on all sites, including cases with radiotherapy. There was 100% success in 19 patients receiving 27 Epiplating implants for auricular prostheses. Radiotherapy as well as chemotherapy does have a negative effect on implant survival. Visser et al. [29] reported a survival rate of 86.2% of implants for auricular

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a

b

c

d

Fig. 8. Surgical steps with the Epiplating system in the microtia patient shown in fig. 9. a The skin flap is elevated with the periosteum. In this case 2 universal platees are bent to fit the mastoid surface. The plate is held in place while it is fixed with bone screws. A Brånemark implant for a BAHA is placed at the same time. b A periostal flap is dissected in the area of the Epiplating implants, and soft tissue reduction is carried out. c Two percutaneous base posts are connected to the universal plates with the aid of an octagonal applicator. d Titanium healing caps are screwed into the base posts of the Epiplating system. Hematoma formation is prevented by compression using ointment-soaked ribbon gauze.

a

b

c

Fig. 9. a The gentleman with unilateral microtia shown in fig. 8 is wearing an implant-retained auricular prosthesis. (Mathias Schneider, anaplastologist, Zweibrücken, Germany). b Close-up view. c The skin penetration site. A bar construction is used for coupling the prosthesis to the implants.

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b

c

d

e

f

Fig. 10. Surgical steps for the patient shown in figure 11. a Squamous cell carcinoma of the back of the auricle. b An impression mould of the pinna is taken. c After radical tumor resection, a periostal flap is dissected. The tragus is preserved. The ideal sites of implantation are marked with methylene blue. d An Epiplating ear plate with 3 threaded openings for magnets is bent to the bony surface and placed subperiostally. e The periosteum is folded back over the implant, and covered with a split thickness skin glaft. The skin is penetrated by 3 base posts. f Hematoma formation is prevented by compression using ointment-soaked ribbon gauze wrapped under the titanium healing caps.

Fig. 11. a The patient shown in Fig. 10 is wearing the implant retained auricular prosthesis. (Jörn Brom, anaplastologist, Heidelberg, Germany). b Close-up view of the skin penetration site with 3 magnets.

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prostheses in irradiated patients as opposed to 95.7% in the non-irradiated population. Granström [30] found a significantly higher incidence of Brånemark implant failures – including dental implants – of 23.3% in irradiated patients compared to 10.8% in nonirradiated patients. With the use of hyperbaric oxygen therapy, there was a significant lower implant failure rate of 8.5% when compared to 40.2% in the population without hyperbaric oxygen therapy [30]. However, this treatment protocol is being debated [31]. A non-randomized US multicenter trial failed to find a significant difference in the survival rate for orbital implants [6]. Placement of implants before institution of radiotherapy is definitively preferable. Otherwise, one should postpone implantation to approximately 1 year after radiotherapy. Implant surgery should always be done in a 2-stage procedure, and the healing phase extended to 6 months.

Complications The adverse skin reactions can be graded according to the scoring system of Holgers et al. [32], where 0 = no reaction, 1 = reddish, 2 = red and moist, 3 = granulation tissue and 4 = skin infection to such a degree that the abutment has to be removed. A Swedish study reported that 92.5% of BAHA patients, 91.1% of patients with orbital prostheses and 89.3% of patients with auricular prostheses had Holgers scores of 0 [32]. There is rarely any discomfort, even in the presence of irritated skin, around the implant. Extensive soft tissue reduction is of paramount importance in order to achieve a reaction-free skin penetration site. Cleaning with mild soap is crucial. If a skin irritation occurs, the abutment should be checked for loosening. There is only 1 severe complication reported worldwide: a brain abscess that occurred following a change of BAHA abutment 8 years after implantation [33].

Contraindications An absolute contraindication for implant surgery is severe psychiatric disease (e.g. severe dementia) or a bad medical condition (e.g. cachexia). Poor hygiene and drug/ alcohol addiction are relative contraindications.

Management of Candidates for Rehabilitation with Auricular Prostheses

The management of these patients depends to a large extent on the etiology of the auricular deficit with its associated factors (e.g. radiotherapy in cancer patients) and the age of the patient. The prosthetic options should be discussed with the patient (and parents) in a team with the anaplastologist, including the need for osseointegrated implants to ensure retention. In many instances, but not all, this requires removal of

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Table 1. Advantages and disadvantages of (implant-retained) auricular prostheses Advantages

Disadvantages

Well suited for complex anatomical structures: ear, nose and orbit

Not ideal for replacement of mobile parts of face

Optimal camouflage

‘Foreign body’ and has to be taken off at night

No donor site morbidity

Color mismatch with changing complexion; discoloration by cigarette smoke

Cosmetic result is predictable (can be shown before surgery)

Cost

Method is simple and fast

Remaking every 2(–3) years

Early detection of tumor recurrence

Immobile

Secure retention1

Skin cleaning routine necessary1

Edges can be made extremely thin to become transparent and blend into the face1 1

Applies to bone anchorage.

an auricular remnant. Implant surgery with soft tissue reduction creates scars that preclude plastic reconstructive surgery with rib cartilage. Although the temporoparietal fascia flap may still be available if the superficial temporal artery was spared, undoubtedly, reconstructive surgery is much more difficult if at all possible. On the other hand, rehabilitation with implant-retained auricular prosthesis always remains an option, even in the case of failed reconstruction. The pros and cons of auricular prostheses (table 1) have to be made clear to the patients. In my experience, it is best if the candidate can meet a patient with an auricular prosthesis in the clinic. Often, this eliminates fears of the skin-penetrating implant and the artificial nature of the prosthesis. However, it also clarifies also the need for implant hygiene and all aspects of life with an auricular prosthesis. Although the prosthesis has to be considered a foreign body, astonishingly, the patients accept it as it was part of their body.

Children Children with microtia can and have been successfully rehabilitated with implantretained auricular prostheses in various institutions, including our own [34, 35]. However, the question of whether this is appropriate in the light of advances in reconstructive surgery remains [36–38]. Often, children develop a sense of malformation only at the age of 10 years. However, some microtia patients without associated

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malformation cope very well, and do not wish to have anything done. Of course, their views may change during puberty. Counseling of these patients and their parents always requires time and dedication to elaborate all of the previously mentioned aspects of care. Sometimes, children can be managed quite well with an adhesive-retained auricular prosthesis. This may serve as an interim solution before any of the available options, and it also helps the child/adolescent in the decision-making process.

Microtia Generally, the microtic ear has to be removed in order to be able to place the implantretained prosthesis in the correct position. However, minor forms of microtia may be used to fix an adhesive-retained prosthesis. Possible drawbacks include adverse effects from the medical adhesive, improper position depending on the remnant, less reliable fixation and difficult positioning. This option should be discussed as a team with the patient. Surgical considerations include the position of the microtic ear, which might be too low and anterior to be hidden by the prosthesis. In which case, its removal should obey plastic surgery principles, as the scar will be visible. Symmetry should be checked both in unilateral and in bilateral microtia cases. Additional malformations, such as in Treacher-Collins syndrome, have to be included in the treatment plan. Otologic surgery of the atretic ear canal can be performed on a patient with a planned implantretained ear prosthesis. However, care has to taken not to unnecessarily remove too much cortical mastoid bone in the region of the ideal implant position described previously. Obviously, combination with the BAHA system poses no difficulties.

Trauma Traumatic amputation or burns can cause partial or total loss of the auricle. Extensive trauma to adjacent sites may preclude cosmetically optimal reconstructive surgery. Bone anchorage is also a good choice for implant-retained partial auricular prosthesis.

Neoplastic Disease Typically, the cancer patient needs radical removal of the tumor according to oncological principles if cure is an option. Provided that there is no doubt about clear margins, the placement of the implants may be done at the same time as the ablative procedure. Otherwise, it is safer to wait for the definitive pathology report. The treatment plan might include radiotherapy and/or chemotherapy in an adjuvant setting. This is detrimental for reconstructive surgery to a much greater extent than implant surgery. The best option is to place the implants before radiotherapy, as discussed in

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‘Results with implants for auricular prostheses’. In any case, visual inspection at cancer follow-up visits provides the best opportunity for tumor control. This can ideally be achieved by prosthetic rehabilitation. Therefore, auricular prostheses are an especially good option for the cancer patient.

Conclusion

The progress made in the development of the silicones allows rehabilitation with an inconspicuous auricular prosthesis (episthesis). The artwork of the anaplastologist in making the prosthesis determines its acceptance by the patient and the success of this approach. Specifically, most patients desire camouflage. Developments in various implant systems allow secure retention, even in unfavorable anatomic situations such as the ideally pneumatized mastoid process. In summary, implant-retained prostheses are a viable treatment option, and more than just an alternative to plastic reconstructive surgery.

References 1 Ring ME: The history of maxillofacial prosthetics. Plast Reconstr Surg 1991;87:174–184. 2 Federspil P, Federspil PA: Die epithetische Versorgung von kraniofazialen Defekten. HNO 1998; 46:569–578. 3 Weerda GH: Retentionselemente fur OhrmuschelEpithesen. HNO 1972;20:83–86. 4 Tjellström A, Lindström J, Hallen O, Albrektsson T, Brånemark PI: Osseointegrated titanium implants in the temporal bone: a clinical study on boneanchored hearing aids. Am J Otol 1981;2:304–310. 5 Tjellström A, Lindström J, Nylen O, Albrektsson T, Brånemark PI, Birgersson B, Nero H, Sylven C: The bone-anchored auricular episthesis. Laryngoscope 1981;91:811–815. 6 Toljanic JA, Eckert SE, Roumanas E, Beumer J, Huryn JM, Zlotolow IM, Reisberg DJ, Habakuk SW, Wright RF, Rubenstein JE, Schneid TR, Mullasseril P, Garcia LT, Bedard JF, Choi YG: Osseointegrated craniofacial implants in the rehabilitation of orbital defects: an update of a retrospective experience in the United States. J Prosthet Dent 2005;94:177–182. 7 Miller KL, Faulkner G, Wolfaardt JF: Misfit and functional loading of craniofacial implants. Int J Prosthodont 2004;17:267–273. 8 Federspil PA, Federspil P, Schneider MH: Magnetverankerung in der Epithetik; in Blankenstein F (ed): Magnete in der Zahnmedizin. Rottweil, Flohr, 2001, pp 104–109.

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9 Brånemark PI, Hansson BO, Adell R, Breine U, Lindström J, Hallen O, Öhman A: Osseointegrated implants in the treatment of edentulous jaw: experience from a 10-year period. Scand J Plast Reconstr Surg 1977;11:1–175. 10 Albrektsson T, Eriksson AR, Friberg B, Lekholm U, Lindahl L, Nevins M, Oikarinen V, Roos J, Sennerby L, Astrand P: Histologic investigations on 33 retrieved Nobelpharma implants. Clin Mater 1993; 12:1–9. 11 Zarb GA, Albrektsson T: Osseointegation – a requiem for the periodontal ligament? Int J Periodontics Restorative Dent 1991;11:88–91. 12 Albrektsson T, Brånemark PI, Hansson HA, Lindström J: Osseointegrated titanium implants: requirements for ensuring a long-lasting, direct bone-to-implant anchorage in man. Acta Orthop Scand 1981;52:155–170. 13 Schön R, Schmelzeisen R, Shirota T, Ohno K, Michi K: Tissue reaction around miniplates used for the fixation of vascularized iliac crest bone grafts. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 1997; 83:433–440. 14 Hwang K, Schmitt JM, Hollinger JO: Interface between titanium miniplate/screw and human calvaria. J Craniofac Surg 2000;11:184–188. 15 Granström G: Craniofacial osseointegration. Oral Dis 2007;13:261–269.

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16 Köle H, Wirth F: Befestigung von Epithesen mit Gerüstimplantaten. Fortschr Kiefer Gesichtschir 1956;2:187–189. 17 Köle H: Erfahrungen mit Gerüstimplantaten unter die Schleimhaut und Haut zur Befestigung von Prothesen und Epithesen. Fortschr Kiefer Gesichtschir 1965;10:76–79. 18 Farmand M: Ein neues Implantat-System für die Befestigung von Epithesen (Epitec®-System). Dtsch Z Mund Kiefer Gesichtschir 1991;15:421–427. 19 Federspil PA, Plinkert PK: Knochenverankerte Hörgeräte immer beidseitig! HNO 2002;50:405– 409. 20 Hölzl M, Caffier P, Jungk J, Scherer H, Schrom T: Das Ti-Epiplating-System für die Knochenverankerung von Hörhilfen. Laryngorhinootologie 2007; 86:193–199. 21 Sandner A, Bloching M: Erfahrungen mit einem subperiostalen Plattensystem aus Titan (‘Ti-EpiplatingSystem’) zur epithetischen Rehabilitation von Mittelgesichts- und Orbitadefekten. Klin Monatsbl Augenheilkd 2004;221:978–984. 22 Volkenstein S, Dazert S, Jahnke K, Schneider M, Neumann A: Epithetische Versorgung von Gewebedefekten in Kopfbereich. Laryngorhinootologie 2007;86:854–860. 23 Watson RM, Coward TJ, Forman GH: Results of treatment of 20 patients with implant-retained auricular prostheses. Int J Oral Maxillofac Implants 1995;10:445–449. 24 Tolman DE, Taylor PF: Bone-anchored craniofacial prosthesis study: irradiated patients. Int J Oral Maxillofac Implants 1996;11:612–619. 25 Parel SM, Tjellström A: The United States and Swedish experience with osseointegration and facial prostheses. Int J Oral Maxillofac Implants 1991;6: 75–79. 26 Wolfaardt JF, Wilkes GH, Parel SM, Tjellstrom A: Craniofacial osseointegration: the Canadian experience. Int J Oral Maxillofac Implants 1993;8:197– 204. 27 Junker OH: Epithetische Rehabilitation kraniofazialer Defekte. Eine Langzeituntersuchung über 12 Jahre bei 200 Patienten; dissertation, Universität des Saarlandes, Homburg (Saar), 2006.

28 Farmand M: Die epithetische Rehablitation von Patienten mit Gesichtsdefekten mit dem EpitecSystem – Grundlagen, Prinzipien, Resultate; in Schwipper V, Tilkorn H, Sander U (ed): Fortschritte in der kraniofazialen chirurgischen Epithetik und Prothetik. Reinbek, Einhorn, 1997, pp 78–88. 29 Visser A, Raghoebar GM, van Oort RP, Vissink A: Fate of implant-retained craniofacial prostheses: life span and aftercare. Int J Oral Maxillofac Implants 2008;23:89–98. 30 Granström G: Osseointegration in irradiated cancer patients: an analysis with respect to implant failures. J Oral Maxillofac Surg 2005;63:579–585. 31 Donoff RB: Treatment of the irradiated patient with dental implants: the case against hyperbaric oxygen treatment. J Oral Maxillofac Surg 2006;64:819–822. 32 Holgers KM, Roupe G, Tjellstrom A, Bjursten LM: Clinical, immunological and bacteriological evaluation of adverse reactions to skin-penetrating titanium implants in the head and neck region. Contact Dermatitis 1992;27:1–7. 33 Scholz M, Eufinger H, Anders A, Illerhaus B, Konig M, Schmieder K, Harders A: Intracerebral abscess after abutment change of a bone anchored hearing aid (BAHA). Otol Neurotol 2003;24:896–899. 34 Granström G, Bergström K, Odersjo M, Tjellström A: Osseointegrated implants in children: experience from our first 100 patients. Otolaryngol Head Neck Surg 2001;125:85–92. 35 Han K, Son D: Osseointegrated alloplastic ear reconstruction with the implant-carrying plate system in children. Plast Reconstr Surg 2002;109:496– 503, discussion 504–495. 36 Berghaus A: Implantate für die rekonstruktive Chirurgie der Nase und des Ohres. Laryngorhinootologie 2007;86:67–76. 37 Siegert R, Magritz R: Die Rekonstruktion des äusseren Ohres. Laryngorhinootologie 2007;86:121– 140. 38 Staudenmaier R: Optimierung der Ohrmuschelrekonstruktion mit autologem Rippenknorpel. Erfahrung aus 120 Fällen. HNO 2006;54:749–755.

Dr. Philipp A. Federspil Department of Oto-Rhino-Laryngology, University Hospital Heidelberg Im Neuenheimer Feld 400 DE–69120 Heidelberg (Germany) Tel. +49 6221 56 6705, Fax +49 6221 56 33637, E-Mail [email protected]

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Staudenmaier R (ed): Aesthetics and Functionality in Ear Reconstruction. Adv Otorhinolaryngol. Basel, Karger, 2010, vol 68, pp 81–94

Combined Aesthetic and Functional Reconstruction of Ear Malformations Jan Kiefera ⭈ Rainer Staudenmaierb a HNO Zentrum Regensburg, Regensburg, and bDepartment of ENT, Head and Neck Surgery, Klinikum rechts der Isar, Technische Universität München, Munich, Germany

Abstract Background: Surgery for major malformations of the outer and middle ear involves aesthetic as well as functional aspects. Whereas reconstruction of the auricle with autogenous rib cartilage is well established and has shown favorable results, functional repair using classic reconstructive techniques is possible only in a limited group of patients and the outcome is often unsatisfactory. Active middle ear implants (MEI) offer a promising alternative to reconstructive surgery. Method: Fifteen patients with ear malformations underwent implantation of an active middle ear implant (Soundbridge®), with or without concomitant reconstruction of the auricle. The vibrating element, the floating mass transducer (FMT), was coupled either to the round window, stapes, oval window or incus, according to each individual’s anatomical middle ear situation. Aesthetic as well as functional outcomes were evaluated. Results: Implantation could be integrated into aesthetic reconstruction of the auricle without complications. In 14/15 patients, a satisfactory functional result could be achieved (<30 dB pure-tone audiometry). Neither facial nerve palsy nor inner ear hearing loss was observed after implantation. Conclusion: The versatile form of the FMT of the Soundbridge allows for adaptation of the coupling procedure to the individual anatomical situations. Implantation of a Soundbridge MEI is a valuable option for functional reconstruction of the malformed ear, which may offer more consistent and reliable results than classic reconstructive surgery. Copyright © 2010 S. Karger AG, Basel

Classic microtia is in most cases combined with aural atresia of the external ear canal as well as considerable dysplasia of the middle ear, involving the ear drum, the ossicles, the facial nerve and possibly the oval and round window niches. Typically, a functional impairment with conductive hearing loss of around 50–60 dB is present. The reduced hearing ability, especially in patients with bilateral microtia, will challenge speech and language development. Therefore, fitting a bone-conducting hearing aid is mandatory in the first months of the patient’s life to ensure normal development. However, patients with a unilateral malformation may also suffer from functional impairment in addition to the aesthetic problem, e.g. in noisy acoustic environments.

Therefore, treatment of microtia in combination with aural atresia and middle ear malformation has to take into account the functional as well as the aesthetic aspect of the disease. Siegert et al. [1] evaluated malformed petrous bones in patients with third-degree microtia using high-resolution CT, and found atresia of the external auditory canal in 88% and normal middle ear ossicles in only 3%. The most common dysplasia of middle ear structures is related to the complex of the malleus and incus. In 69%, this had morphological malformations, and in 27% it was absent. Severe abnormalities of the labyrinth were rare in these patients. Moreover, displacement of the facial nerve canal can be expected in about 77% of patients with auricular dysplasia, a fact that has important implications for surgery in these cases. Both auricle reconstruction and reconstruction of a malformed middle ear with atresia are difficult and challenging operations. While reconstruction of the auricle mostly produces an excellent aesthetic outcome, the indication for operations improving hearing ability by building up the external auditory canal and middle ear should be judged carefully, because functional outcomes vary widely and are often unsatisfactory. The chances of achieving a satisfactory result depend on the individual anatomical situation, which is evaluated preoperatively by high-resolution CT of the petrous bone and can be judged with the help of radiological scores [1, 2]. In general, all authors agree that surgical reconstruction of the ear canal, ear drum and middle ear should only be attempted in patients with favorable anatomical conditions, e.g. a present stapes and sufficiently aerated middle ear. However, even in cases which are eligible to undergo surgical reconstruction, reduced hearing ability requiring an air conduction hearing aid remains at least in more than half of patients, even in the series of most experienced centers. Because of this limited success rate, reconstruction of the external ear canal and the middle ear is commonly only recommended in cases of bilateral microtia. Active middle ear implants (MEI), also referred to as implantable hearing aids were developed for the treatment of sensorineural hearing loss, and have been successfully used in large series of patients [3]. They provide acoustic amplification and transmission of sound energy by direct coupling of a vibratory element to the ossicular chain. Currently, 2 systems are available, a partially implantable device (the MED-EL Vibrant Soundbridge) and a fully implantable device, which has been introduced in the European Union. The Soundbridge consists of an external audio processor and an implantable part, the vibrating ossicular prosthesis (fig. 1). The active vibrating element is a small electromagnetic element called the floating mass transducer (FMT), which is normally coupled to the long process of the incus with the ossicular chain intact. It transmits the vibrations to the stapes footplate. In malformed ossicular chains, however, this way of coupling is generally difficult or impossible because anatomical abnormalities may frequently prevent correct placement and fixation to the chain. In addition, the ossicular chain in the malformed ear is often immobile. Fixation of a vibrating transducer to a fixed ossicular chain would probably not transmit enough energy to the inner ear. However, alternative

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Receiving coil Magnet

Conductor link VORP transition

29 mm

FMT

Demodulator 130 mm

4.6 mm deep

VORP transition

Fig. 1. Soundbridge middle ear implant.

methods of coupling may exist. Classic experiments by Wever and Lawrence [4] have demonstrated that the transfer of vibratory energy to the inner ear and the subsequent evocation of hearing sensations can be achieved at every point of the cochlea [via ossicles and stapes, directly at the footplate of the oval window, at the round window, or via a newly created third window (fenestration) of the cochlea]. Thus, the various strategies of coupling the FMT to the inner ear fluid will probably result in adequate hearing sensation. The FMT might be coupled directly to a mobile stapes footplate if the oval window niche is large enough and surgically accessible. Based on computer model calculations and the first clinical results reported by Colletti et al. [5], stimulation of the cochlea by coupling the FMT to the round window membrane may be a promising second alternative [6]. Round window stimulation may be regarded as a reversal of the normal pathway of activation of the basilar membrane. Provided that effective and stable coupling of a vibratory transducer can be achieved surgically, active implantable hearing aids offer a promising opportunity for reliable and reproducible functional rehabilitation of middle ear malformations, and may avoid complications of surgical reconstruction and circumvent the disadvantages of conventional hearing aids in reconstructed outer ear canals. Aesthetic reconstruction of the outer ear is well established, and in general gives very satisfying results. The most common way of auricular reconstruction is the use of autogenous rib cartilage based on the technique described by Nagata [7]. Further development and refinement of the technique [8–11] has made it possible to achieve excellent results in the majority of patients, if performed by experienced surgeons.

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In the first step, the cartilage framework is created and transplanted under the skin of the mastoid plane. In a second operation a few months later, the new auricle is raised by placing a cartilage wedge under the base plate of the auricle framework. In order to accomplish the reconstruction, the posterior side of the framework and the cartilage wedge are covered with a full-thickness skin graft. Commonly, a third step is necessary for minor refinements. In an attempt to combine esthetical and functional reconstruction, we have initiated a study to evaluate the feasibility of using an implantable hearing aid for functional restoration in conjunction with reconstruction of the auricle using autologous rib cartilage. The aim of this report is to demonstrate the feasibility of this technique and outline the surgical procedures that are used.

Method Preliminary Considerations Within the group of possible candidates for combined esthetical and functional reconstruction using an active middle ear implant, 3 groups may be differentiated according to the sequence of surgical steps. These are patients who have: complete reconstruction of the outer ear before an MEI is inserted; reconstruction of the outer ear performed at the same time as implantation of an MEI; implantation of an MEI preceding reconstruction of the outer ear. The timing of the implantation in relation to the auricle reconstruction is of importance. If the implantation is performed prior to the reconstruction, incision lines have to be planned carefully after consultation with the surgeon responsible for the plastic reconstruction to avoid scars that interfere with the reconstructive procedure. If implantation is planned concomitantly to the reconstruction, we have to consider at which stage implantation would be best performed. Integrating the implantation into the reconstructive procedure has the principle advantage of avoiding an additional surgical intervention. The reconstructive surgery comprises 2 principle steps. During the first step, the cartilage framework is built from costal cartilage and placed into subcutaneous tissue. During the second step, the auricle is elevated and retroauricular sulcus is formed. A critical point during the first step is possible skin breakdown or infection. It is possible that implantation at that stage would increase the risk of skin breakdown and infection, since tissue manipulation and tension would be increased, and put the implant at risk. In addition, preparation of the subsequent steps might harm the electrode of the implant. We therefore favor integrating the implantation into the second stage of reconstruction, when the skin and framework have already stabilized and are sufficiently revascularized. However, implantation may also be performed after reconstructive surgery has already been finished. Implantation after completed reconstruction also imposes an additional surgical procedure, but, other than this, it has no major disadvantage if the incisions and manipulation avoid damaging the vascularization of the newly formed auricle.

Preoperative Diagnostics and Preparations for Surgery • Assessment of auricular deformity and atresia at birth. • Early postnatal pediatric counseling with a general physical examination to search for other congenital anomalies.

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• Early evaluation of auditory function in both unilateral and bilateral atresia. • Bone-conduction brainstem-evoked response audiometry for bilateral cases of congenital aural atresia within the first few weeks of life. The incidence of an association between an inner ear abnormality and congenital aural atresia is uncommon, but must be excluded. • Imaging in cases of aural atresia can be postponed until surgery is planned. • For reconstruction of the outer ear canal or middle ear high-resolution CT scans in both the axial and coronal planes are important. The following are critical pieces information required for possible repair: ⴰ presence of sufficient space to create a new ear canal; ⴰ degree of pneumatization of the temporal bone; ⴰ presence and appearance of the ossicular chain; ⴰ course of the facial nerve, focusing on the relationship of the horizontal portion to the oval window and the location of the mastoid segment; ⴰ existence of the oval window and stapes footplate; ⴰ existence of a round window and its relation to the facial nerve; ⴰ anatomy of the cochleovestibular system. Reconstruction of the outer ear canal and middle ear is recommended between the 5th and 10th years of life; reconstruction of the auricle with autogenous rib cartilage is usually possible from age 8 years upwards, when sufficient cartilage is available. Favorable conditions for Soundbridge implantation are: • Sufficiently pneumatized mastoid process; • Aerated tympanic cavity; • Presence of ossicular chain (incus-malleus complex, stapes); • Detectable oval and round windows; • Route of the facial nerve that allows access to the target structure for coupling. If available, 3D reconstruction may be helpful for planning the surgical access. Navigated surgery may be a useful option; however, the authors have not yet used this technique in surgery of the malformed ear. The operation should always be carried out under facial nerve monitoring to prevent injury to this particular nerve, which is especially at risk in implantation of the malformed ear.

Surgical Procedures Reconstruction of the Auricle and Preparing the Implant Bed In the first step, the future position of the auricle is determined by taking into account the hairline and degree of hemifacial dysplasia. If present, the contralateral normal ear is used as a model. A stencil of the normal ear is built, sterilized, and used intraoperatively to adjust the dimensions of the new auricle to the normal contralateral ear. The cartilage is harvested from the 6th, 7th and 8th ribs, and then the cartilage framework is created (fig. 2). This is transplanted into a subcutaneous pocket of the mastoid plane, in the desired position. In the second operation, which is scheduled about 8 weeks after the first operation (after complete healing and recovery of the soft tissue), the auricle will be elevated and the retroauricular sulcus created. For this step, a curved retroauricular incision is used. If implantation of the MEI is planned at this step, the incision is enlarged posteriorly by using an incision line perpendicular to the retroauricular incision (fig. 3a). The periosteum is incised in a line created with regard to the skin incision, in order to avoid infection of the implant in case of skin suture dehiscence (fig. 3b). In general, placement of the implant housing should follow the established guidelines of cochlear implant surgery. The position of the housing should be planned with sufficient distance between the posterior rim of the cartilage framework and the anterior rim of the housing to

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a

c

b

Fig. 2. Case study: 9-year-old boy with grade III dysplasia. a Preoperative situation. b Cartilage framework built out of autologous rib cartilage. c Aesthetic result after 2 operations. MEI implantation was performed at a later stage.

a

b

c

d

Fig. 3. Integration of MEI into the second stage of auricle reconstruction: operative procedure. a Incision line. b Preparation of the musculoperiosteal flap and the pocket for the implant housing. c Combined transmastoid/meatal access and placement of the implant. d Positioning the FMT against the round window membrane (access under the facial nerve ).

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Fig. 4. Postoperative results after combined reconstruction of the auricle and MEI.

avoid later conflict and implant exposure in cases of skin problems at the newly formed retroauricular sulcus. A bony bed for the implant should be drilled at the appropriate position and tie-down sutures should be prepared to hold the implant securely in place. These tie-down sutures can be fixed to the bone or to the surrounding periosteum. After completed placement of the implant housing (fig. 3c) and closure of the periosteal layer, a semi-lunar piece of cartilage is placed under the auricular framework to form the posterior conchal wall and to elevate the new auricle. This cartilage is then covered with a pedicled superficial temporalis flap or a mastoidal musculoperiosteal flap to provide secure soft tissue coverage of the cartilage. Grafting of the rear aspect of the auricle with a thin split-thickness skin graft completes the formation of the retroauricular sulcus. Surgical Access to the Middle Ear Based on the preoperative CT scan, surgical access is planned either as a transmastoid procedure (if the mastoid is sufficiently pneumatized), a transcanal procedure involving drilling along the course of the atretic ear canal (if the mastoid is not pneumatized), or a combined procedure using both access routes in combination. The starting point should be determined using intraoperative landmarks, such as a visible mold in the region of the pars tympanica, the horizontal line of the zygomatic arch and the mandibular fossa. They should be related to the CT scan to determine the correct drilling position. Navigated surgery could be a helpful tool. For the transmastoid approach, the technique is generally similar to the technique used for cochlear implantation, with cortical or complete mastoidectomy, and identification of the middle fossa plate, the sigmoid sinus, the horizontal semicircular canal and the short process of the incus. However, the posterior tympanotomy should not be performed until the facial nerve is clearly identified. Therefore, it may be recommended to open the epitympanum until the incus is clearly observed. Then, the facial nerve can be identified underneath in relation to the oval window and the stapes, and the course of the facial nerve can then be carefully followed visually by opening the facial recess (starting superiorly). As the facial nerve often travels more laterally and anteriorly in its mastoid portion in malformed ears, it may sometimes be necessary to pass underneath the facial nerve to gain access to the middle ear, e.g. the round window (fig. 3d). The middle ear structures, ossicles and oval and round windows are exposed as far as possible to be able to choose the optimal structure for coupling the FMT. The final results of combined functional and aesthetic reconstruction are shown in fig. 4.

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Fig. 5. Different modalities for coupling the FMT to vibratory structure. a On top of the stapes; the clip was bent downward and fixed on the stapes suprastructure. b Hanging sideways onto a bony connection between the incus and stapes; the clip was bend sideways (indicated by the white lines) and covered with temporalis fascia. c Against the round window membrane after interposition of a fascia temporalis graft. d Coupling to the long process of the incus.

a

b

c

d

Coupling the FMT to the Vibratory Structures In malformed middle ears, the incus and malleus often form a synostotic complex that is fixed anteriorly to the pars tympanica of the temporal bone. The long process may be abnormally formed or missing. Therefore, classic coupling of the FMT to the long process of the incus is often impossible or not the best choice. If a stapes is present, mobile and sufficiently stable to support the FMT, direct coupling to the stapes head is possible. This might be achieved by direct superposition or placement of the FMT parallel to the stapes, fixing the FMT with a bend-over attachment. If the stapes’ suprastructure is unstable or missing, then direct coupling to a mobile footplate is another option. If the footplate is not mobile or the round window niche is too narrow, then enlarging the oval window and drilling a fenestration in the round window niche is another option. In some cases, neither the ossicles nor the oval window may be readily accessible. Placement of the FMT against the round window membrane is another alternative way of coupling the FMT to the inner ear fluid that has been shown to give excellent results. A visual overview of these possibilities is presented in figure 5.

Patients In this series, we included 15 patients who underwent MEI implantation, either with or without reconstruction of the auricle. The age at implantation varied greatly, the youngest implantee was 5.7 years old, the oldest was 45 years old. Etiology was idiopathic in the majority of cases, 1 patient had Franceschetti/Treacher-Collins syndrome and 1 patient presented with CHARGE syndrome. Six of fifteen patients had a normal external ear, and the remainder had grade II–III dysplasia (Weerda classification); 6/15 patients had a normal ear canal, while the others showed subtotal

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stenosis or aplasia. Middle ear abnormalities were found in all patients. In 1 patient, who had undergone a previous attempt at reconstructing the external ear canal, a retention cholesteatoma was found intraoperatively during the implantation of the MEI. The cholesteatoma was removed in the same operation.

Results

Table 1 summarizes the operative procedures in terms of reconstruction of the auricle, operative access to the middle ear, coupling of the FMT and global outcome. Coupling to the round window niche was used most frequently (n = 8), followed by coupling to the stapes (n = 4). Due to the limited number of patients and the wide variations in etiology, individual anatomy and target of coupling, it is not possible at this stage to evaluate subsets of patients. In the following, we will therefore refer to the results of the overall group. Wound healing was complete and without problems in all patients: no infection, suture insufficiency or wound healing problems in the area of the free skin graft were observed. All but 2 patients obtained satisfactory hearing results after primary placement of the FMT. One patient had to be revised, as primary coupling to the round window niche was not satisfactory. After revision under local anesthesia with replacement of the FMT to the oval window niche, we obtained a satisfactory result. In 1 child, neither placement at the oval window niche nor the round window niche resulted in hearing sensation, although preoperative hearing tests suggested a mixed bilateral hearing loss (severe on the implanted ear, moderate on the contralateral ear) with a moderate inner ear hearing loss at the implanted side. Preoperative tests with a boneanchored hearing aid were positive, and the child reported hearing on the implanted side. However, neither placement on the oval window niche or round window niche resulted in hearing sensation on the implanted ear. Figure 6 presents the mean preoperative air conduction thresholds versus postoperative aided thresholds. Preoperative thresholds ranged between 70 and 60 dB. Aided thresholds with the Soundbridge were significantly increased (with a bell-shaped curve) in the main speech frequencies [mean values between 38 dB (0.5 kHz) and 22 dB (1.5 kHz)]. The mean functional gains with the Soundbridge MEI ranged between 20 and 36 dB (fig. 7); in some individual cases, this reached 65 dB. The hearing in the main speech frequency area was optimal, while in the high-frequency area it was sufficient. A weakness in amplification of the low-frequency area could be noted. This is probably due to technical limitations of the FMT (low weight and floating mass). However, in all patients tested so far, speech understanding was significantly increased in comparison to the preoperative situation, and subjective benefits were large. All patients who were successfully implanted continue to use the MEI during all waking hours, including those patients with unilateral malformation. They report increased ease of listening, spatial hearing and the benefit of being able to hear from both sides.

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Table 1. Etiology and operative procedure by patient No.

Etiology

Laterality

Procedure for auricle

Access

Placement of FMT

Complications

1

Franceschetti syndrome

bilateral

bilateral reconstruction

transcanalicular

RWN

none

2

unknown

bilateral

none

transmastoideal

RWN

none

3

middle ear malformation

unilateral

none

transmastoideal

RWN

none

4

unknown

bilateral

none

transmastoideal

RWN

none

5

unknown

unilateral

unilateral reconstruction

transmastoideal

RWN

none

6

unknown

unilateral

unilateral reconstruction

transmastoideal

RWN

none

7

unknown

bilateral

none

transmastoideal

OWN

dislocation of FMT and repositioning

8

unknown

unilateral

unilateral reconstruction

transmastoidal

RWN

none

9

Franceschetti syndrome

bilateral

bilateral reconstruction

transmastoidal

RWN

none

10

unknown

unilateral

none

transmastoidal

stapes

none

11

unknown

unilateral

unilateral reconstruction

transmastoidal

stapes

none

12

CHARGE syndrome

bilateral

none

transmastoidal and transmeatal

RWN

repositioning from OWN to RWN

13

unknown

unilateral

unilateral reconstruction

transmastoidal

stapes

none

14

unknown

unilateral

unilateral reconstruction

transmastoidal

stapes

none

15

unknown

unilateral

unilateral reconstruction

transmastoidal

incus

none

RWN = Round window niche; OWN = oval window niche.

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–10 0

Air-condution threshold (dB HL)

10 20 30 40 50 60 70 80 90 100 110

Fig. 6. Mean aided thresholds with the Soundbridge (black) versus preoperative air-conduction thresholds (gray).

120 0.125

0.25

0.5

1 1.5 2

3 4

6

8

kHz

80 70

Gain (dB)

60 50 40 30 20 10 0 –10

125

250

500

1,000

1,500

2,000

3,000

4,000

6,000

8,000

Frequency (Hz)

Fig. 7. Functional gain with the Soundbridge. Gray lines represent individual data; black lines represent mean values.

Discussion

Functional and aesthetic rehabilitation of combined malformation of the auricle, outer ear canal and the middle ear still remain a challenging surgical task. Reconstruction of the auricle can be performed with autogenous rib cartilage in a 2-stage procedure

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[8–11]. In experienced hands, excellent results can be obtained. If the vascularization of the local skin is compromised, e.g. by previous surgery, this technique can be combined with a pedicled auriculotemporal flap to provide additional vascularization to the cartilage framework and the skin. Replacement of an auricle fixed with a boneanchored prosthesis is a valuable alternative (in the elderly, for example); however, prostheses have to be replaced at regular intervals and psychological acceptance of autogenous reconstruction is better, as the implant forms an integral part of the body and offers a definitive solution. Functional reconstruction, on the other hand, still holds many unsolved questions. Bone-anchored hearing aids can be used to restore the hearing of the malformed ear. However, the bone anchors, although often well-tolerated, may cause local infection and/or skin reactions in about 10% of patients; furthermore, they require meticulous daily care, and the rate of extrusion varies between 2% in adults and 5% in children. Also, bone-conduction devices only offer limited directional hearing, as both cochleae are stimulated simultaneously. Surgical reconstruction of the outer ear and restoration of the ossicular chain is a possible alternative. A new outer ear canal is drilled, either by an endaural approach (following the normal anatomical course of the outer ear canal) or a transmastoid approach (forming a modified radical cavity). This approach can be used if the mastoid is well pneumatized. The creation of an outer ear canal can also be combined with reconstruction of the auricle [12]. In a 2-stage procedure, the ear canal is formed with autologous rib cartilage, stabilized by a silicone stent and epithelialized with a skin graft. However, in all of these techniques, restenosis of the ear canal, thickening, scarring or blunting of the neo-eardrum and infections are still common problems. In addition, reconstruction of a functional ossicular chain is often difficult, if not impossible, when the stapes is severely malformed or absent, the oval window niche is missing or the footplate fixed. Jahrsdoerfer et al. [2] described a scoring system which underlines the significance of the condition of the stapes. Jahrsdoerfer scores of at least 7–8/10 are commonly recommended before an attempt to perform reconstructive surgery. Thus, only a limited number of malformed ears may be eligible for reconstructive surgery [13]. Unfortunately, even when this material is used in the best of hands, postoperative long-term residual conduction hearing loss usually remains between 20 and 40 dB, requiring the postoperative use of hearing aids to make full use of the functional value of the reconstructed ear. The use of hearing aids is difficult in reconstructed ear canals, as earmolds are often not well tolerated and prone to recidivating infections and the accumulation of debris. Firmin et al. [14] also combined the construction of the auditory canal with auricle reconstruction, similarly integrating the functional procedure of atresia surgery and tympanoplasty in the second step of correcting the microtia. To line the drilled hole, they use a subgaleal fascial flap to ensure a well-vascularized

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ground for the skin graft. After the otological procedure, the subgaleal fascia flap is harvested together with the galeal fascia, used for the reconstruction of the retroauricular sulcus and covering the posterior surface of the auricular framework and the cartilage wedge. After placing a split-thickness skin graft on the subgaleal flap, the new canal and the conchal cavity are filled with Gelfoam for stabilization. This kind of reconstruction also lacks mechanical stability and leads very often to restenosis. With the use of computer-assisted surgery and facial nerve monitoring in atresia surgery, the risk of injury to the facial nerve is reduced. In a retrospective study, Caversaccio et al. [15] compared intra- and postoperative clinical and audiological findings of atresia surgery using computer-assisted surgery with similar interventions that were applied without computer-assisted surgery. Computer-assisted surgery in congenital bony aural atresia, which is combined with altered petrous bone anatomy and scarcity of surgical landmarks, provides the surgeon with increased safety and accuracy in critical situations. This fact reduced the mean operating time in the evaluated cases by 25 min. In combination with facial nerve monitoring, the rate of complications (e.g. dysfunction of the facial nerve) can be reduced and the new external ear canal can be maximally enlarged, which minimizes the complication of postoperative restenosis.

Conclusion

In the present study, a new technique of combining aesthetic and functional reconstruction has been evaluated. We were able to integrate the implantation procedure into the auricle reconstruction procedure; thus, avoiding the need for a further intervention. Functional results of implantation were satisfactory, obtaining air conduction thresholds of 30 dB or better in the majority of patients, including patients with unfavorable conditions on preoperative CT scan who were not eligible for classic reconstructive surgery. The versatile form of the FMT of the Soundbridge allows for adaptation of the coupling procedure to each individual anatomical situation. It appears to be very suitable for implantation in malformed ears. Implantation of MEI is a valuable option for functional reconstruction of the malformed ear, which may offer more consistent and reliable results than classic reconstructive surgery, and should be evaluated in larger series of patients.

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References 1 Siegert R, Weerda H, Mayer T, Brückmann H: Hochauflösende Computertomographie fehlgebildeter Mittelohren. Laryngo Rhino Otol 1996;75:187– 194. 2 Jahrsdoerfer RA, Yeakley JW, Aguilar EA, Cole RR, Gray LC: Grading system for the selection of patients with congenital aural atresia. Am J Otol 1992;13:6–12. 3 Sterkers O, Boucarra D, Labassi S, Bebear JP, Dubreuil C, Frachet B, Fraysse B, Lavieille JP, Magnan J, Martin C, Truy E, Uziel A, Vaneecloo FM: A middle ear implant, the Symphonix Vibrant Soundbridge: retrospective study of the first 125 patients implanted in France. Otol Neurotol 2003; 24:427–436. 4 Wever EG, Lawrence M: The Place Principle in Auditory Theory. Proc Natl Acad Sci USA 1952;38: 133–138. 5 Colletti V, Soli SD, Carner M, Colletti L: Treatment of mixed hearing losses via implantation of a vibratory transducer on the round window. Int J Audiol 2006;10:600–608. 6 Kiefer J, Arnold W, Staudenmaier R: Round window stimulation with an implantable hearing aid (Soundbridge®) combined with autogenous reconstruction of the auricle – a new approach. ORL J Otorhinolaryngol Relat Spec 2006;68:378–385. 7 Nagata S: A new method of total reconstruction of the auricle for microtia. Plast Reconstr Surg 1993;92: 187–201.

8 Brent B: The correction of microtia with autogenous cartilage grafts. I. The classic deformity. Plast Reconstr Surg 1980;66:1–12. 9 Nagata S: Modification of the stages in total reconstruction of the auricle. I. Grafting the three-dimensional costal cartilage framework for lobule-type microtia. Plast Reconstr Surg 1994;93:221–230. 10 Weerda H: Reconstructive surgery of the auricle. Facial Plast Surg 1988;5:399–410. 11 Staudenmaier R, Aigner J, Kastenbauer E: Mikrotie. Technik zur Ohrmuschelrekonstruktion mit autologem Rippenknorpel. Handchir Mikrochir Plast Chir 2001;33:163–170. 12 Siegert R, Weerda H: Two- step external ear canal construction in atresia as part of auricular reconstruction. Laryngoscope 2001;111:708–714. 13 Shonka DC Jr, Livingston WJ 3rd, Kesser BW: The Jahrsdoerfer grading scale in surgery to repair congenital aural atresia. Arch Otolaryngol Head Neck Surg 2008;134:873–877. 14 Firmin F, Gratacap B, Manach Y: Use of the subgaleal fascia to construct the auditory canal in microtia associated with aural atresia. Scand J Plast Reconstr Hand Surg 1998;32:49–62. 15 Caversaccio M, Romualdez J, Baechler R, Nolte LP, Kompis M, Häusler R: Valuable use of computedassisted surgery in congenital bony aural atresia. J Laryngol Otol 2003;117:241–248.

Jan Kiefer HNO Zentrum Regensburg, Neupfarrplatz 12 DE–93047 Regensburg (Germany)

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Staudenmaier R (ed): Aesthetics and Functionality in Ear Reconstruction. Adv Otorhinolaryngol. Basel, Karger, 2010, vol 68, pp 95–107

Combined Reconstruction of Congenital Auricular Atresia and Severe Microtia Ralf Siegert Department of Oto-Rhino-Laryngology, Head and Neck Surgery, Prosper Hospital, Ruhr University Bochum, Recklinghausen, Germany

Abstract Objectives: Due to their embryological development, auricular atresia and severe microtia are, in most cases, combined malformations. The aims of this study were firstly to develop a surgical technique for combined esthetic and functional reconstruction with a minimum of operations and secondly to evaluate its results. Study Design: Prospective clinical evaluation. Patients and Methods: Fifty-two patients with third-degree microtia and congenital aural atresia with a sound-conducting block of about 50 dB were treated. In the first operation, autogenous cartilage was harvested, and the auricular framework was fabricated and implanted. In addition, the tympanic membrane and the external ear canal were prefabricated, and stored in a subcutaneous pocket. In the second step, the elevation of the new framework was combined with the operation for atresia, utilizing the prefabricated tympanic membrane and external ear canal. In the third step, the cavum concha was deepened, and the external ear canal was opened and covered with a skin graft. Results: In total, 76% of the patients had a final conductive hearing loss of 30 dB or less. No restenosis of the new external ear canal was observed. The esthetic results of the constructed auricles are shown in this report. Conclusion: With this combination of plastic surgery for the auricle and functional surgery for the middle ear, no additional operations are necessary and the prefabrication of the external ear canal and the tympanic membrane gives stable and reliable results. This combined technique offers the best chance of optimal esthetic and functional rehabilitation for patients with these malformations. Copyright © 2010 S. Karger AG, Basel

Introduction

Due to their embryological development, auricular atresia and severe microtia are, in most cases, combined malformations. Therefore, optimal rehabilitation of these patients requires reconstruction of the auricle and the middle ear. Preliminary results presented at the 8th International Symposium of the American Academy of Facial Plastic and Reconstructive Surgery, New York, 1– 5 May 2002.

Tympanoplasty of the malformed middle ear with atresia is supposed to be one of the most difficult and challenging operations in middle ear surgery – often with an unpredictable outcome [1, 2]. Whereas some highly specialized surgeons have reported their own acceptable results [3–5], other patients not operated on by these specialists had only disappointing outcomes [6]. After at least 1 year postoperatively, their average air-bone gap was not less than 50 dB, although most of them were reoperated upon several times [6]. One of the very common complications is restenosis of the newly constructed external ear canal [1]. This can be avoided in most cases by a 2-step procedure presented by Siegert and Weerda [7]. Construction of the whole auricle in severe microtia or total amputation is regarded as one of the most challenging procedures in facial plastic surgery. Weerda and myself have performed more than 600 total auricular reconstructions during the last 15 years in our institutions in Luebeck and Recklinghausen, Germany. Our techniques are based on the work of Brent [8] and Nagata [9], among others. After having gained experience in auricular reconstruction and having developed a technique for the stable construction of the external ear canal, our next step towards optimal esthetic and audiological rehabilitation was its combination with tympanoplasty for atresia. Beginning with techniques described by Jahrsdoerfer [4], Schuknecht [5] and others, we modified the tympanoplasty by prefabrication of the tympanic membrane and the external ear canal, extending it into a 3-step procedure and combining it with the reconstruction of the auricle. This method and its results to date are presented here.

Materials and Methods Preoperative Diagnostics As in any kind of atresia surgery, preoperative high-resolution CT of the petrous bone is mandatory [10]. We perform this during the patient’s initial stay in the hospital for the first stage of auricular reconstruction. The CT scan is evaluated carefully with regard to the criteria published elsewhere [10, 11], and the malformation is quantified according to our index system [10], which is a modification of the Jahrsdoerfer scale [12]. Only in cases where the patient achieves 20 out of 28 possible points in unilateral and 15/28 in bilateral conditions is middle ear surgery later performed.

First Operation Reconstruction of the auricle is based on the techniques described by Brent [8], Nagata [9] and others. We incise the skin above the 7th rib in males, and in the submammary fold in females. Ribs 6–9 are exposed and their cartilage, including the superficial perichondrium, is harvested. The inner perichondrium of ribs 6–8 is left in place, and used to reconstruct the ribs as we have described elsewhere [13]. The 3-dimensional auricular framework is created out of ribs 7–9 (fig. 1). The skin

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Ib

IIIb

IIa IIb

IIIa

Ia

Fig. 1. Auricular framework created from ribs 7–9.

Fig. 2. Ia Silastic cylinder (11 mm diameter, of 20 mm length) around which the ear canal is prefabricated. Ib Tympanic membrane mould comprised of 2 cylinders (15 mm diameter each, and a 0.5 mm gap in-between), bridged by 3 small Silastic bars. IIa tube used as a place holder for the prefabricated ear canal. IIb cylinder that fits into the tube 2a. IIIa sheet to cover the new tympanic membrane. IIIb tube that fits into the new ear canal with a skin graft.

of the severely malformed auricle is incised, and the lobule transposed using the technique described by Nagata [9] whenever this is possible due to its size and location. The remnants of the elastic auricular cartilage are excised and utilized to prefabricate the tympanic membrane. To do so, they are cut into small thin slices of 0.3–0.5 mm thickness. These pieces are packed densely into a special mold made out of Silastic (fig. 2 part IB, fig. 3), which has the shape of 2 cylinders (15 mm diameter each) with a 0.5 mm gap in-between, bridged by 3 small Silastic bars to connect the cylinders and keep the width of the gap. The external ear canal is also prefabricated. It is formed out of rib hyaline cartilage with perichondrium cut into pieces with a thickness of approximately 3 mm. They are positioned around a Silastic cylinder with a diameter of 11 mm and a length of 20 mm (fig. 2 part IA, fig. 4). The prefabricated tympanic membrane and the prefabricated external ear canal are enveloped into a resorbable net (Vicryl®), and stored together with the cartilage of the 6th rib in a subcutaneous pocket of the thoracic wound. These 3 pieces will be used in the second step. The auricular framework is transplanted under the mobilized skin of the auricular region. Two suction drainages pull the skin into the relief of the framework, and a special bandage of foam rubber (Spiggle and Theis, Germany) with a hole and a cover prevent external pressure onto the skin.

Second Operation The 2nd operation is not performed earlier than 6 months postoperatively. A full-thickness spindle-shaped skin graft (FTSG; 4.5 × 11 cm) is harvested from the thorax, which includes the scar from the 1st operation, so that no additional scar is produced. The 3 subcutaneously stored pieces,

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Fig. 3. Tympanic membrane mould comprised of 2 cylinders (15 mm diameter each, and a 0.5 mm gap in-between), bridged by three small Silastic bars.

B A C

Fig. 4. Rib hyaline cartilage with perichondrium (3-mm pieces) positioned around a Silastic cylinder (11 mm diameter, 20 mm length).

Fig. 5. The 3 subcutaneously stored pieces. A Cartilage of the 6th rib. B, C Prefabricated constructions.

i.e. the cartilage of the 6th rib and the 2 prefabricated constructions, are also harvested (fig. 5). The latter (fig. 5, parts B and C) will have developed into stable biological formations. Dense connective tissue will have connected the little pieces of rib cartilage of the prefabricated external ear canal and stabilized it, so that a robust cartilage tube has developed. Its inner surface is composed of a very thin and smooth capsule, which typically grows around Silastic implants [14]. The new auricle is mobilized from the retroauricular, elevated and superficial temporalis fascia (STF) connected to its vessels (fig. 6 part E). Now, the framework is shifted so far forward that the periosteum of the atretic bone up to the capsule of the temporomandibular joint is exposed. The periosteum is incised in an ‘H’ shape, and elevated so that the bone of the mastoid planum is exposed. Starting from the temporal line, the drilling begins. Bone dust is saved, as long as no mastoid cells are exposed, to be used later for the reconstruction of the mastoid planum. The drilling is performed under visual or computer-assisted orientation with reference to the highresolution CT of the petrous bone as well as facial nerve monitoring. In this way, all precautions are taken to avoid any damage to the important seventh cranial nerve. As soon as the tympanic space is reached, care has to be taken not to touch the ossicles with a rotating bur. Small diamond burs and House spoons are used to remove the atretic plate. Bony connections or adherences to the malformed malleus-incus complex (MIC) are removed, and the

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A D E

B

C

Fig. 6. A Elevated constructed auricle from posterior, covered with soft connective tissue. B constructed external ear canal with Silastic cylinder. C entrance of the external ear canal with Silastic cylinder. D buttress sutured to the base plate of the auricular framework. E superficial temporalis fascia utilized to cover the cartilage buttress. Auricular framework covered with the mobilized STF.

Fig. 7. The skin of the cavum concha is incised in a ‘Z’ fashion, forming 2 triangles.

ossicles checked for mobility and movement transmission to the stapes. If there is doubt about a good sound transmission from the MIC to the stapes, the MIC is removed and reconstructed with a partial ossicular replacement prosthesis (PORP); otherwise, it is of course preserved. As PORP, we use a titanium prosthesis (Kurz, Germany), which for our purposes the producers modify to various lengths up to 10 mm. The prefabricated tympanic membrane (PTM) is placed onto the MIC or the PORP. Care must be taken to maintain antral drainage. A small cartilage bridge from the facial canal to the skull base may be necessary, onto which the prefabricated tympanic membrane is placed. Now the length, angle and thickness of the PEEC are adjusted according to the individual anatomical situation. A special Silastic tube with the same external diameter as the cylinder around which the canal was prefabricated (fig. 2 part IIa) is inserted into the new canal. The advantage of using this tube instead of using the cylinder again lies in the possibility of checking the correct position of the canal on the tympanic membrane through the tube till the end of the microscopic part of the operation. Now the prefabricated external ear canal (PEEC) is positioned onto the PTM and stabilized with pieces of cartilage, which are wedged in-between the canal and the bone of the remaining mastoid planum. They are also used to reconstruct the planum. Gaps in-between the cartilage pieces are filled with the bone dust collected earlier. After the correct position of the PEEC on the PTM has been checked through the Silastic tube, another smaller special Silastic cylinder with the appropriate diameter (fig. 2 part IIb) is inserted into the tube down to the PTM. These 2 Silastic implants, the tube and the cylinder, are constructed to fit precisely, with a very small gap remaining (1 mm) that allows only slow sliding in water or water-like fluid. Finally, the subcutaneously stored cartilage of the 6th rib is carved to fit under the anthelix (fig. 6). It is fixed to the base plate of the auricular framework, and covered with the mobilized STF (fig. 6 part E). The FTSG is sutured onto the STF to cover the new retroauricular fold.

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Fig. 8. Abundant scar and connective tissue are removed to deepen the cavum, and the Silastic tube and cylinder are exposed.

a

b

Fig. 9. a, b FTSG wrapped around the tube in a cup-like fashion, and sutured to itself with its epithelium facing inward.

Third Operation Again, this step is performed 6 months later at the earliest. The skin of the cavum concha is incised in a ‘Z’ fashion forming 2 triangles (fig. 7), and raised as very thin flaps. Abundant scar and connective tissue is removed to deepen the cavum to an appropriate size, and the Silastic tube and cylinder are exposed (fig. 8). The principles of this part of the operation have been published in our prior publication [7], and have been further modified. The implants are removed easily by grasping them with forceps and rotating them slightly. Now, the very smooth capsule covering the PEEC and PTM comes into sight. The mobility of the PTM can be checked. The length of another special Silastic tube with a diameter 1 mm less than the one just removed is adjusted roughly to the individual length of the new canal (fig. 2 part IIIb). It must not be shorter but may be a little longer than the canal. To cover the external ear canal, another spindle-shaped FTSG (3 × 9 cm) is harvested from the thorax. Again, it includes the already present scar, so that no additional scar is produced. The FTSG is wrapped around the tube in a cup-like fashion with its epithelium facing inward (important!) and sutured to itself (fig. 9). A little bit of fibrin glue is poured onto the FTSG, which is then pushed with the tube into the canal. Because this tube is only 1.6 mm smaller than the tube already in place, there is no gap between the FTSG and the inner lining of the PEEC. A special round Silastic sheet with a thickness of 0.1 mm

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a

Fig. 10. a–c The new external ear canal, 1 week postoperatively.

b

c

(fig. 2 part IIIa) is placed onto the skin graft at the bottom of the tube covering the FTSG on the reconstructed tympanic membrane to keep it in place. Finally, the tube is filled with a kind of gauze.

Postoperative Treatment and Follow-Up One week postoperatively, the gauze, the Silastic tube and the Silastic sheet are removed while avoiding any suction onto the still vulnerable FTSG. Now the new external ear canal, nicely covered with skin, can be seen (fig. 10). An ointment is applied into the canal and the patient is discharged from the hospital. Follow-up visits for clinical evaluation and audiology are scheduled 1 month and 1 year postoperatively, or otherwise on demand. The air-bone gap in pure-tone audiometry was averaged for the frequencies 1, 2 and 3 kHz.

Histology In 2 cases, we had abundant prefabricated material in the 2nd step. In 1 case, the PEEC was too long and in the other one the PTM was too large. They had to be trimmed according to the

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Fig. 11. Patient before (a) and after (b) the procedure.

a

Fig. 12. Patient before (a) and after (b) the procedure.

a

b

b

individual anatomical requirements of the patient. Both excised pieces were evaluated histologically.

Results

Fifty-two patients with uni- (35 right, 13 left) or bilateral [4] third-degree microtia have been or are being treated with this procedure. Thirty-eight of them are male and 14 are female. Their ages range from 9 to 41 years (mean 14.9 ± 7.0 years, median 11.8 years). Three patients are between steps 1 and 2, 8 patients are between steps 2 and 3, and 41 patients have had the third step (fig. 11, 12). Three have been lost to follow-up, and 38 have had an average follow-up of 9 months (up to 3.5 years). In 27 patients, the MIC was removed and substituted by a PORP. In 9 patients, a special PORP was placed onto the MIC.

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Fig. 13. Histologic specimens from a prefabricated tympanic membrane (PTM) and a prefabricated external ear canal (PEEC). (a) PTM, H&E staining, original magnification x5. (b) PTM, H&E staining, original magnification x20. (c) PEEC, EvG staining, original magnification x40.

a

b

c

Two patients showed a slight temporary threshold shift in bone conduction audiometry after the 2nd step, for which tympanoplasty was performed. They both returned to their normal preoperative bone-conducting threshold within 1 week. Slight clinically and audiologically irrelevant restenosis occurred in 2 patients. None of the others showed any severe restenosis. Instead, all had nice smooth external ear canals (fig. 10). No paresis of the facial nerve, no alopecia (from harvesting the STF) or any other complication occurred in this series. Preoperatively, all patients had a complete sound-conducting block (50 dB on average, measured by pure-tone audiometry) and an average bone conduction threshold of 10 dB. Postoperatively, the residual air-bone gap was 26 ± 12 dB (n = 37); 59% had an air-bone gap of ≤25 dB and 76% of ≤30 dB. The bone conduction threshold increased slightly to 8 dB on average. Whereas, some months are necessary to stabilize the sound conduction, no tendency towards either further decreases or an increases in the air-bone gap during our follow-up (maximum 3.5 years) occurred.

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Histology shows the PEEC is composed of regular viable hyaline rib cartilage with no signs of necrosis (fig. 13c). The PTM is a smooth, 0.5-mm thick plate of pieces of elastic cartilage with intervening fibrous connective tissue (fig. 5 part C and fig. 13a, b). There was only 1 small area of calcification, surrounded by viable elastic cartilage (fig. 13a).

Discussion

As we have shown previously [7], stepwise construction of the external ear canal in severe microtia with congenital atresia is a reliable technique with predictable results. Furthermore, when integrated into the procedures for auricular construction as we have proposed, the patient does not need any additional operations. In cases with good anatomical condition of the petrous bone, the so-called ‘atresia operation’ or tympanoplasty can be performed. We have enlarged our operative concept for these patients by developing a 3-step procedure, which is again integrated into the 3 steps for auricular construction, and thus avoids additional operations for the patients. Its main principles are: • prefabrication of the external ear canal out of hyaline rib cartilage; • prefabrication of the tympanic membrane out of the malformed elastic auricular cartilage; • performing the atresia operation in a 2nd operation with the use of these prefabricated ‘matured’ biological components that have the specific stability and elasticity needed; • opening and skin coverage of the new external ear canal in a 3rd operation after it has healed in its proper position [for more detail, see 7]. In our experience, the advantages of using prefabricated biologically constructed components are that they: • develop a very smooth and sufficiently vascularized capsule around the Silastic implants, which is an excellent bed for the FTSG [7, 14]; • are stable in themselves; • have the necessary elasticity. The normal external ear canal is a predominantly immovable structure. It has slight elasticity in its lateral cartilaginous part proceeding into the elastic auricle. Since the new surgically constructed auricle is made out of relatively stiff rib cartilage, there is no need for elasticity of the external ear canal in these patients. So, the richly available stiff hyaline rib cartilage is not only used for the auricle, but also to form the external ear canal. Reconstruction of the tympanic membrane with cartilage has been a routine technique for various, mainly inflammatory, middle ear diseases for many years [15]. It has proven to be a reliable technique. It shows a low reperforation rate and excellent sound conduction. The optimal thickness of the cartilage should be around 0.5 mm [16]. Due to the positive experiences gained from this technique, we use the elastic cartilage of the

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malformed auricle, which is not needed for any other purpose. This was cut into slices of the suggested thickness of about 0.5 mm. To link these pieces close to each other, they were densely packed into a Silastic form with a gap of the required thickness of 0.5 mm. In 2 cases, we had the opportunity to histologically evaluate pieces of the prefabricated constructions. Of course this does not follow any systematic approach – which would not have been justified ethically – instead these are only exemplary observations. In these specimens, the cartilage pieces were viable and interconnected with dense fibrous tissue. Only 1 area showed a small area of calcification, also surrounded by viable and histologically normal cartilage (fig. 13a). The possibility that this small amount of calcified tissue might significantly deteriorate the acoustic properties is rather unlikely, but cannot be completely excluded by the available data. Whether this small calcification is degenerative in nature and/or due to some kind of iatrogenic contamination with a microscopic foreign body or caused by something else remains uncertain. Nevertheless, no necrotic tissue or any further signs of degeneration were detected after 6 months’ maturation of these prefabricated constructions. Cartilage does not heal like bone or skin, which have the potential to substitute, at least in part, a defect with original tissue. The regrowth of cartilage depends on intact perichondrium, and even then its growth potential is only minor in adult tissue. So, it cannot be expected that the described prefabrication would lead to a tube for the PEEC or thin plate for the PTM of completely normal cartilage. However, this is neither the clinical objective nor necessary. Instead a stable external ear canal with a thin elastic tympanic membrane with good acoustic transmission is desired. To achieve this goal, the described technique of prefabrication and stepwise construction seems to be an important step forward. Clinically relevant restenosis can be avoided, and the sound transmission functions well. Compared to several other studies in very experienced ‘ear-centers’, our results are ‘acceptable’ or ‘good’ (table 1), but they should not be considered the ‘end of the line’. In most cases, the MIC was removed because we thought that it would not allow reliable sound transmission. Whether or not this judgment was correct cannot be proven. It is a subjective decision based on the surgeon’s experience, and far from being evidence-based. In the last cases, we tried harder to drill away from the bone near the MIC and to free it from adhesions so that it was left in place more often, leaving the original connection between the stapes and the MIC unchanged. The PTM was then positioned directly onto the MIC. Whether this will reduce the residual airbone gap even further and how the long-term stability of these constructions develops after more than 4 years will be evaluated by the ongoing follow-up.

Conclusion

In patients with severe microtia and congenital atresia, the described combination of plastic surgery for the auricle and functional surgery for the middle ear can achieve

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Table 1. Results of tympanoplasty for congenital atresia in specialized centers First author

Year

Patients

Patients ≤30 dB n

Patients ≤30 dB %

Meurmann [17] Crabtree [18] Gill [19] Bellucci [20] Jahrsdoerfer [3] Gerhardt [21] Cremers [22] Lambert [23] Schuknecht [5] Molony [24] Shih [25] Teunissen [26] Schwager [27] Lambert [28]

1957 1968 1969 1972 1978 1988 1988 1988 1989 1990 1993 1993 1995 1998

48 23 83 47 20 78 53 15 56 22 30 4 70 46

12 12 28 24 11 23 26 10 30 16 3 1 39 23

25 52 34 51 55 30 49 67 54 72 10 25 56 50

595

288

Sum Average This series

48 2003

37

28

76

stable and reliable results that avoid major complications, like restenosis of the new ear canal, which have compromised this surgery so far. Since tympanoplasty is integrated into the auricular reconstruction procedures, the patient does not need any additional surgery and the canal construction does not influence the auricular surgery or the other way around. Therefore, we believe that this combined technique offers the best chance of optimal esthetic and functional rehabilitation of patients with these malformations.

Acknowledgement I would like to thank Prof. Wierich for his evaluation and description of the histological specimen.

References 1 Weerda H, Bockenheimer S, Trübi M: Gehörverbessernde Operationen bei Ohrmuschelmißbildungen. HNO 1985;33:449–452. 2 Hildmann H, Rauchfuß A, Hildmann A: Indikation und chirurgische Behandlung der großen Mittelohrmißbildung. HNO 1992;40:232–235.

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3 Jahrsdoerfer RA: Congenital atresia of the ear. Laryngoscope 1978;88:1–48. 4 Jahrsdoerfer RA: Surgical correction of congenital malformations of the sound-conducting system; in Shambaugh G, Glosscock M (eds): Surgery of the Ear. Philadelphia, Saunders, 1980, pp 380–407.

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5 Schuknecht HF: Congenital aural atresia. Laryngoscope 1989;99:908–917. 6 Danter J, Weerda H, Semeradt A, Siegert R: Results of middle ear surgery in patients with auricular dysplasias and congenital aural atresias: an analysis of 58 operations in other institutions. Eur Arch Otorhinolaryngol 1997;254:26. 7 Siegert R, Weerda H: Two step external ear canal construction in atresia as part of auricular reconstruction. Laryngoscope 2001;111:708–714. 8 Brent B: Auricular repair with autogenous rib cartilage grafts: two decades of experience with 600 cases. Plast Reconstr Surg 1992;90:355–374. 9 Nagata S: Modification of the stages in total reconstruction of the auricle. Part I. Grafting the threedimensional costal cartilage. Plast Reconstr Surg 1994;93:221–230. 10 Siegert R, Weerda H, Mayer T, Brückmann H: Hochauflösende Computertomographie fehlgebildeter Mittelohren. Laryngorhinootologie 1996;75: 187–194. 11 Mayer T, Brueckmann H, Siegert R, Witt A, Weerda H: High-resolution CT of the temporal bone in auricle and external auditory canal dysplasia. Am J Neuroradiol 1997;18:53–65. 12 Jahrsdoerfer PA, Yeakley JW, Aguilar EA, Cole RR, Gray LC: A grading system for the selection of patients with congenital aural atresia. Am J Otol 1992;13:6–12. 13 Siegert R, Magritz R: Rippenrekonstruktion nach ausgedehnten Knorpelentnahmen zum Ohrmuschelaufbau – oder: ‘Das Tissue Engineering des armen Chirurgen’. HNO Informationen 2001;25: 174. 14 Ginsbach G, Busch LC, Kühnel W: The nature of the collagenous capsules around breast implants. Plast Reconstr Surg 1979;64:456–464. 15 Heermann J: Auriculare cartilage palisade. Clin Otolaryngol 1978;3:433–466.

16 Mürbe D, Zahnert T, Bornitz M, Hüttenbrink KB: Acoustic properties of different cartilage reconstruction techniques of the tympanic membrane. Laryngoscope 2002;112:1769–1776. 17 Meurmann Y: Congenital microtia and meatal atresia: observations and aspects of treatment. AMA Arch Otolaryngol 1957;66:443–463. 18 Crabtree JA: Tympanoplastic techniques in congenital atresia. Arch Otolaryngol 1968;88:71–73. 19 Gill NW: Congenital atresia of the ear: a review of the surgical findings in 83 cases. J Laryngol Otol 1969;83:551–587. 20 Bellucci RJ: Congenital auricular malformations. Indications, contraindications, and timing of middle ear surgery. Ann Otol Rhinol Laryngol 1972;81: 659–663. 21 Gerhardt HJ: One hundred and seventy-five surgically treated malformations of the external and middle ear: findings and results. Auris Nasus Larynx 1988;15:81–87. 22 Cremers and Teunissen Advances Oto-RhinoLaryngology, 40, 9–14. 23 Lambert PR: Major congenital ear malformations: surgical management and results. Ann Otol Rhinol Laryngol 1988;97:641–649. 24 Molony TB, de la Cruz A: Surgical approaches to congenital atresia of the external auditory canal. Otolaryngol Head Neck Surg 1990;103:991–1001. 25 Shih L, Crabtree JA: Long-term surgical results for congenital aural atresia. Laryngoscope 1993;103: 1097–1102. 26 Teunissen EB, Cremers WR: Classification of congenital middle ear anomalies: report on 144 ears. Ann Otol Rhinol Laryngol 1993;102:606–612. 27 Schwager K, Helms J: Microsurgery of large middle ear abnormalities: technical surgical considerations (article in German). HNO 1995;43:427–431. 28 Lambert PR: Congenital aural atresia: stability of surgical results. Laryngoscope 1998;108:1801– 1805.

Prof.Dr.Dr. Ralf Siegert Department of Oto-Rhino-Laryngology, Head and Neck Surgery Prosper Hospital, Ruhr University Bochum Muehlenstrasse 27, DE–45659 Recklinghausen (Germany) Tel. +49 236 154 2551, Fax +49 236 154 2590, E-Mail [email protected]

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Ear Reconstruction through Tissue Engineering Andreas Haisch Department of Otorhinolaryngology, Charité University Medicine Berlin, Berlin, Germany

Abstract For decades, reconstructive surgery of the auricle has presented a challenge to surgeons. An immense number of publications now document the efforts to develop and improve techniques designed to provide reasonable shape and functionality. Since the early 1990s, tissue engineering has become increasingly popular in the field of reconstructive surgery. In particular, when an invitro-manufactured auricular-shaped cartilage implant was implanted on the back of a nude mouse, reconstructive surgeons were intrigued and patients’ expectations were raised. However, almost 20 years after tissue engineering was defined by Langer and Vacanti [Science 1993;260:920–926] as: ‘an interdisciplinary field that applies the principles of engineering and life sciences toward the development of biological substitutes that restore, maintain, or improve tissue function or a whole organ’, only single case reports have been published. These reports detail the clinical application of in-vitromanufactured cartilage for reconstructive procedures in the head and neck. The present article describes the fundamentals and potential of tissue engineering in reconstructive surgery of the auricle, and highlights the limitations that prevent its current clinical application. Copyright © 2010 S. Karger AG, Basel

Tissue Regeneration and Clinical Requirements

The potential of regeneration is clearly seen in nature, for example in the hydra, a member of the phylum Cnidaria (along with sea anemones, jellyfish and coral polyps). The hydra is best known for its ability to regenerate a new head or foot once these organs are cut off. When a hydra is bisected anywhere along the upper part of the body, each part generates the organs that it is missing [1–4]. In contrast to these findings, the capacity of regeneration is only present to a limited extent in humans. A typical example is the healing of superficial epidermal defects, although liver regeneration is far more impressive [5–7]. After injury, the liver has a remarkable capacity to regenerate. Within 8 days of a partial hepatectomy, the hepatic mass is essentially back to presurgical levels [8]. Unfortunately, in other

regions of the human body, these abilities are not present to such an extent, so the head and neck surgeon has to keep reconstructive surgery standards in mind when dealing with tissue defects. In the head and neck region, tumor surgery, dysplasia and trauma result in tissue defects and subsequent deficits in function, alongside cosmetic considerations. One region of special interest for the reconstructive surgeon is the auricle, an area where both functional and cosmetic considerations are strongly present. For decades, the reconstruction of the auricle has posed a challenge for surgeons because of the special requirements of this region. The goal of auricular reconstruction is to restore the partial, dysplastic or completely missing auricular framework by using techniques that all have to mimic the function of elastic cartilage. In the human body, nowhere does cartilage dominate function and morphology with such diversity more than the auricular region. Subcutaneous tissue and skin are mostly available, and have to be attached to the reconstructed cartilaginous auricular shaped framework. Besides establishing standard surgical techniques to reconstruct the auricle, Vacanti [9] described a technical approach to manufacture cartilage tissue in vitro for applications in reconstructive surgery (fig. 1). However, it is surprising that almost 20 years after tissue engineering was defined by Langer and Vacanti [Science 1993;260:920–926] as: ‘an interdisciplinary field that applies the principles of engineering and life sciences toward the development of biological substitutes that restore, maintain, or improve tissue function or a whole organ’, only single case reports describing the clinical application of in-vitro-manufactured cartilage for reconstructive procedures in the head and neck have been published [10, 11]. In comparison to articular reconstruction by tissue engineering, the reconstruction of the auricular region is far more challenging. In order to fully understand the complexity of this approach, some basic information about cartilage tissue is presented here first.

Cartilage Tissue and Engineering

Cartilage is a mesenchymal tissue that provides mechanical stability, flexibility and shape. Three types of cartilage have been distinguished (hyaline, elastic and fibrocartilage), which are characteristic of the joints, trachea, nasal septum, vertebral discs and the auricle [12, 13]. In general, cartilage consists of cells (chondrocytes), extracellular matrix components (proteoglycans and collagen) and water. Chondrocytes represent 1–2% of adult cartilage tissue, and regularly produce an extremely low amount of extracellular matrix components. The extracellular matrix consists of collagen fibers supporting glycoproteins and proteoglycans that are associated with glycosaminoglycan molecules, such as chondroitin sulfate and hyaluronic acid [14]. Beside collagen, the other contributor to the mechanical stability of cartilage is water, which serves as a carrier in the metabolic exchange of waste and nutrients. Auricular

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Fig. 1. The tissue engineering procedure starts with a small cartilage biopsy from the contralateral auricle. This is followed by chondrocyte isolation and amplification in vitro. Finally, the chondrocytes are rearranged within a 3D auricular-shaped biomaterial mold, and transferred to the patient by the surgeon.

cartilage is characterized by the presence of elastin [15]. In contrast to the auricular elastic cartilage, hyaline and fibrocartilage are composed of different amounts of collagen type I and collagen type II [16]. Only elastic and hyaline cartilage have a perichondrium, which contains some pluripotent progenitor cells and protects the cartilage from damage, as well as playing a role in metabolic processes [17]. The ability of cartilage to repair damage is very limited due to the low mitotic cellular activity and the low cellular density within native cartilage [18]. The major element in cartilage repair is the ability of chondrocytes to switch from a steady-state phenotype to a mitotic phenotype when separated from the surrounding extracellular matrix [19]. In the human organism, this is seen in damaged cartilage, where the repair mechanism is activated to restore lost chondrocytes and extracellular matrix components (fig. 2) [20, 21]. In ex vivo experimental settings, this mechanism is utilized to amplify chondrocytes harvested from a comparatively small cartilage biopsy, unlike the established surgical techniques that use extensive amounts of rib cartilage. In the initial step, chondrocytes are enzymatically isolated from the surrounding extracellular matrix. After this, the isolated chondrocytes are amplified by the addition of isolated amplification-stimulating growth factors (BMPs, IGF) or fetal calf sera [22–26]. Although the amplification procedure is limited to approximately 4 passages, matching a

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In vivo II Monolayer I + III 3-D culture X+I X + II

II

Fig. 2. Shifting of chondrocyte morphology in dependence upon environmental conditions.

multiplication factor of 100–1,000, the technique generally provides a sufficient amount of chondrocytes for the following chondrocyte transplant arrangement. This procedure guarantees low donor site morbidity, and allows the amplification of the chondrocytes within an established laboratory setting. During the amplification process within a 2D monolayer culture, the chondrocytes shift their morphology from a round-oval shape to a fibroblast-like shape. Cartilage-specific collagen type II production is changed to unspecific collagen type I and type III production [27, 28]. This unspecific phenotype expression is continued to the point where the chondrocytes are transferred to a 3D setting. After the transfer of the chondrocytes to a 3D alignment, the chondrocytes shift to a cartilage-specific phenotype with the expression of collagen type II and further cartilage-specific matrix components, finally reconstructing the extracellular cartilage matrix [29]. Therefore, the chondrocytes have to be transferred into a biomaterial that allows a homogenous 3D chondrocyte distribution and good conditions for chondrocyte metabolism. In contrast to the author’s protocols, which use adult chondrocytes, alternative stem cells from various sites are available for use within a 3D biomaterial [30]. The multipotency of the stem cells allows differentiation to every imaginable tissue type [31]. Morphogenes that are added as a supplement to the stem cell culture media guarantee the differentiation of stem cells to chondrocytes; thus, restoring the extracellular cartilage matrix. Corresponding to adult chondrocyte engineering, stem cells also need a 3D environment to restore the extracellular matrix components under controlled conditions. Within the avascular adult extracellular cartilage matrix, metabolism takes place by diffusion and is generally limited by the diffusion distance. Mimicking the porosity of native cartilage by approximately 75%, the biomaterials have to allow high cell adherence and homogenous distribution as well as guaranteeing enough space for newly synthesized matrix components (fig. 3). The biomaterial itself should not interact with these mechanisms, especially when large amounts of chondrocytes are applied. According to the space needed within the biomaterial for newly built

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Biomechanical properties Shapeability Stability

Porosity

Materials

science

Degradation rate

Surface properties Biomaterial

Interaction with immune system

Bioactivity

Biology

Medicine

Growth factors

Fig. 3. Factors that influence the selection of a biomaterial for cartilage engineering.

Neovascularization Cell number

matrix components, the biomaterial degrades proportionately. Furthermore, the degrading biomaterial has to guarantee an initial biomechanical stability while the cartilage matrix stability increases simultaneously with extracellular cartilage matrix production. In tissue engineering research, the efforts undertaken to find an optimal biomaterial for cartilage engineering have been immense. Despite this, the requirements of a biomaterial are still being discussed and are highly controversial (fig. 3). Most authors favour bioresorbable materials that disappear quickly, although some authors have made good arguments for the application of non-resorbable biomaterials [30, 32–34]. Besides bioresorption, there are also further variables to consider. Two different biomaterial designs are under investigation: fiber-like and gel-like. Both have advantages and disadvantages, just as bioresorbable and non-bioresorbable materials, that determine which kind should be applied. In general, organic-polyester-based biomaterials, like polyglycolide/polylactic acid fibers or gels, are well-established in cartilage engineering because of their specific characteristics [10]. Other well-established organic biomaterials are hyaluronic acid- and collagen-based gels or fibers [10]. Table 1 shows the wide range of different types of biomaterials available, separated into 3 groups according to their clinical aspect. Every single biomaterial is characterized by specific material properties, expressing an individual profile that determines the pros and cons of its application in cartilage engineering. For instance, fiber-like materials generally offer better biomechanical characteristics compared to gel-like materials [33, 35–37]. In contrast to this, gel-like materials guarantee better 3D distribution and adherence of the chondrocytes compared to porous fiber-like materials [38, 39].

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Table 1. Biomaterials suitable for tissue engineering grouped by clinical characteristics Non-bioresorbable polymers

Bioresorbable polymers

Polymers of biological origin

Polyethylene Polyvinylidene fluoride Polytetrafluoroethylene Polyvinyl alcohol Polyhydroxyalkanoate Polyethylene terephthalate Polybutylene terephthalate Poly(methyl methacrylate) Polyhydroxyethylmetacrylate Poly(N-isopropylacrylamide) Polydimethylsiloxane Polypyrrole Polyethylene oxide

Polyglycolic acid Polylactic acid Polydioxanone Poly(lactic-co-glycolic acid) Poly-ε-caprolactone Polyanhydride Polyphosphazene Poly(ortho-ester)

Alginate Chondroitin-6-sulfate Chitosan Hyaluronic acid Collagen Polylysine Dextran Heparin Fibrinogen/Thrombin

3D Framework Design

A further aspect of great importance, especially in auricular cartilage engineering, is the shape of the cartilage fragment or the entire auricular framework to be restored. Therefore, the biomaterial not only has to guarantee the microscopic 3D alignment of the chondrocytes, but also has to demonstrate characteristics that allow an acceptable macroscopic design of the framework itself. Depending on the biomaterial, the technique used to shape of the framework varies. Basic non-hardware-based techniques are based on classical epithetic and dental shaping methods. A mould from the contralateral auricle is taken with an alginate material, and copied by mirroring techniques using wax and silicone moulds (fig. 4). Based on the mirrored silicone mould, a polyethylene mould is prepared that will serve as the point of origin for the auricle prototype. The auricular-shaped silicone mould is sterilized and filled with the selected biomaterial (fig. 5). The author’s protocol applies a combination of PLLA-PGLA fibers and fibrin gel to combine the advantages of both materials within 1 substance [30, 40]. A suspension of chondrocytes and fibrinogen is added to the fiber framework within the auricular-shaped silicone mould. The addition of thrombin cross-links the fibrinogen to fibrin and completes the chondrocyte-biomaterial fusion. A bioreactor setting allows continuous media supply and waste disposal until the cartilage framework has replaced the degrading biomaterial [41–43]. The technique described here is very basic and inexpensive, but time-consuming. An alternative technique has been transferred from industrial design strategies. This technique is based on rapid prototyping, which is used in the auto industry and other design-dependent industries with the need to visualize newly developed prototypes. The name rapid prototyping is taken from the rapid processing of the 3D framework.

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Fig. 4. Auricular mold preparation by the classical handcrafting technique.

However, the method is expensive due to the hardware required. A high-performance computer station acquires and calculates the data from a CT or MRI scan, and later transfers the data to a rapid prototyping printer. Depending on the biomaterial used, the prototyping printers use the liquid phase of the material to build the 3D framework layer-by-layer (e.g. multi-jet modeling, stereolithography) or use a laser technique (e.g. laser sintering, contour crafting) to shape the 3D framework of a solid biomaterial [44]. The precision of the technique applied is ultimately limited by the resolution (with a range of 0.5 to several millimetres, depending on the biomaterial used). In conclusion, every technique available guarantees 3D shaping of the biomaterial, and subsequently the cartilage transplant [45].

In vivo Characteristics

Compared to orthopedic cartilage engineering techniques, the application of cartilage tissue engineering in the head and neck region is completely different. The recipient area in the head and neck region is typically the subcutaneous space, in contrast to the orthopedic region where it is normally the intra-articular space. The subcutaneous region is characterized by active immunological responses throughout wound-healing. In tissue engineering, autogenous tissue is generally applied, so a potential rejection of the transplant by the immune system is avoided. The predominant immunological

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Fig. 5. Auricle transplant molding technique.

pathway is phagocytosis [46]. Animal testing has demonstrated severe effects upon the tissue-engineered cartilage transplants arising from the type of biomaterial used and the state of differentiation characterized by the amount of newly built cartilage matrix within the transplant. The effects upon the immature cartilage are characterized by chondrocyte and collagen matrix reduction leading to transplant instability and deformation, which in turn affect the shape [47–49]. The effects of the immune system upon the cartilage transplant become more pronounced if the biomaterial stimulates the immune system by degradation products (or by the biomaterial itself) and the cartilage matrix does not protect the antigen-presenting chondrocyte surface. Several techniques, such as local and systemic immune suppression or transplantencasing techniques, have been analyzed with the objective of reducing the effects of phagocytosis upon the cartilage transplant. Immune suppression (e.g. by corticosteroids) gives a reduction in phagocytosis, but does not guarantee complete protection of the cartilage maturation after implantation [50]. Transplant-encasing techniques by alginate encapsulation or by polyelectrolyte complex membrane encapsulation depend on the biomechanical and immunological characteristics of the membrane. The membrane has to guarantee reliable and persistent encapsulation of the cartilage transplant over a defined period, while allowing the passage of nutrition and waste products. These requirements are defined by the cutoff of the membrane. The

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polyelectrolyte complex membrane technique allows the adjustment of a specific cutoff, but has the disadvantage of stimulating the immune system by the membrane itself, leading to a fibrocellular scar layer around the cartilage transplant with the risk of cutting off the cartilage metabolism [51–53]. Compared to alginate encapsulation, these findings are considerably reduced in polyelectrolyte complex membranes. The polyelectrolyte complex membrane technique appears to be a promising approach that requires adaption to the specific requirements of cartilage engineering. In summary, none of the techniques offers reliable protection to the immature cartilage from phagocytosis after subcutaneous implantation. Despite these findings, in nude mice and rabbit animal models, the in vivo maturing of cartilage transplants has been successfully performed by several research groups and these techniques have been applied. Furthermore, the biomechanical characteristics (such as Young’s modulus and maximum failure load) of in vivo tissue-engineered cartilage are comparable with the biomechanical characteristics of native joint and nasal cartilage [47, 54]. In all mammalian studies, phagocytosis was an important influence upon the quality of the subcutaneously implanted cartilage constructs and any subsequent functional instability and loss of shape.

Summary and Perspectives

The clinical application of tissue engineering to reconstruct an entire auricular framework has never been reported. Reconstructing the auricular framework using tissue engineering techniques is currently not a viable option, mainly due to the unsolved problem of protecting the immature cartilage/biomaterial matrix from phagocytosis during wound-healing. Nevertheless, the in vitro techniques and the biomaterials available allow the manufacturing of an entire custom-made chondrocyte-biomaterial framework in vitro. Furthermore, in vitro, the chondrocytes produce a cartilage-specific matrix over a cultivation period of several weeks, optionally using a bioreactor setting. In complete or partial immunocompetent animal models, like nude mice and rabbits, the formation of mature cartilage has been clearly demonstrated. The functional and cosmetic results were comparable to native cartilage from various sites. However, in pigs, the techniques demonstrated have failed, although autogenous transplantation has been performed. In the near future it is possible that biomedical techniques could enable scientists to overcome the problems reported by targeting the cellular level on both sides: the chondrocytes as well as the phagocytic cluster. In addition, the biomaterial might become smarter, influencing the cell-biomaterial interaction as well as the biomaterial-host interaction. These goals are only achievable when interdisciplinary teams of biotechnologists and clinicians work together. In the meantime, the well-established surgical techniques extensively described in this volume are giving exceptional results in the hands of experienced surgeons.

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40 Haisch A, Klaring S, Groger A, Gebert C, Sittinger M: A tissue-engineering model for the manufacture of auricular-shaped cartilage implants. Eur Arch Otorhinolaryngol 2002;259:316–321. 41 Bujia J, Sittinger M, Hammer C, Burmester G: Culture of human cartilage tissue using a perfusion chamber (in German). Laryngorhinootologie 1994; 73:577–580. 42 Minuth WW, Sittinger M, Kloth S: Tissue engineering: generation of differentiated artificial tissues for biomedical applications. Cell Tissue Res 1998;291:1– 11. 43 Sittinger M, Schultz O, Keyszer G, Minuth WW, Burmester GR: Artificial tissues in perfusion culture. Int J Artif Organs 1997;20:57–62. 44 Staudenmaier R, Naumann A, Aigner J, Bruning R: Ear reconstruction supported by a stereolithographic model. Plast Reconstr Surg 2000;106:511– 512. 45 Cohen S, Bano MC, Cima LG, Allcock HR, Vacanti JP, Vacanti CA, Langer R: Design of synthetic polymeric structures for cell transplantation and tissue engineering. Clin Mater 1993;13:3–10. 46 Shieh SJ, Terada S, Vacanti JP: Tissue engineering auricular reconstruction: in vitro and in vivo studies. Biomaterials 2004;25:1545–1557. 47 Haisch A, Duda GN, Schroeder D, Groger A, Gebert C, Leder K, Sittinger M: The morphology and biomechanical characteristics of subcutaneously implanted tissue-engineered human septal cartilage. Eur Arch Otorhinolaryngol 2005;262:993– 997. 48 Eyrich D, Wiese H, Maier G, Skodacek D, Appel B, Sarhan H, Tessmar J, Staudenmaier R, Wenzel MM, Goepferich A, Blunk T: In vitro and in vivo cartilage engineering using a combination of chondrocyteseeded long-term stable fibrin gels and polycaprolactone-based polyurethane scaffolds. Tissue Eng 2007;13:2207–2218. 49 Monroy A, Kojima K, Ghanem MA, Paz AC, Kamil S, Vacanti CA, Eavey RD: Tissue engineered cartilage ‘bioshell’ protective layer for subcutaneous implants. Int J Pediatr Otorhinolaryngol 2007;71: 547–552. 50 Haisch A, Wanjura F, Radke C, Leder-Johrens K, Groger A, Endres M, Klaering S, Loch A, Sittinger M: Immunomodulation of tissue-engineered transplants: in vivo bone generation from methylprednisolone-stimulated chondrocytes. Eur Arch Otorhinolaryngol 2004;261:216–224.

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51 Haisch A, Groger A, Gebert C, Leder K, Ebmeyer J, Sudhoff H, Jovanovic S, Sedlmaier B, Sittinger M: Creating artificial perichondrium by polymer complex membrane macroencapsulation: immune protection and stabilization of subcutaneously transplanted tissue-engineered cartilage. Eur Arch Otorhinolaryngol 2005;262:338–344. 52 Haisch A, Groger A, Radke C, Ebmeyer J, Sudhoff H, Grasnick G, Jahnke V, Burmester GR, Sittinger M: Protection of autogenous cartilage transplants from resorption using membrane encapsulation (in German). HNO 2000;48:119–124.

53 Haisch A, Groger A, Radke C, Ebmeyer J, Sudhoff H, Grasnick G, Jahnke V, Burmester GR, Sittinger M: Macroencapsulation of human cartilage implants: pilot study with polyelectrolyte complex membrane encapsulation. Biomaterials 2000;21: 1561–1566. 54 Duda GN, Haisch A, Endres M, Gebert C, Schroeder D, Hoffmann JE, Sittinger M: Mechanical quality of tissue engineered cartilage: results after 6 and 12 weeks in vivo. J Biomed Mater Res 2000;53:673– 677.

Andreas Haisch, MD, PhD Department of Otorhinolaryngology, Head and Neck Surgery Campus Benjamin Franklin, Charité University Medicine Berlin Hindenburgdamm 30, DE-12200 Berlin (Germany) Tel. +49 308 445 2431, Fax +49 308 445 4460, E-Mail [email protected]

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Staudenmaier R (ed): Aesthetics and Functionality in Ear Reconstruction. Adv Otorhinolaryngol. Basel, Karger, 2010, vol 68, pp 120–131

Customized Tissue Engineering For Ear Reconstruction Rainer Staudenmaiera ⭈ Nguyen The Hoanga,e ⭈ Veronika Mandlika ⭈ Christian Schurra ⭈ Marc Burghartza ⭈ Katharina Haubera ⭈ Gerhard Meierb ⭈ Günter Kadeggec ⭈ Torsten Blunkd a

Department of ENT, Head and Neck Surgery, Klinikum rechts der Isar, Technische Universität Munich, Munich, bPolyMaterials, Kaufbeuren, cKL-Technik, Gauting, and dDepartment Technische Pharmazie, Universität Regensburg, Regensburg, Germany; eDepartment of Microsurgery, Institute of Trauma and Orthopedics, Central Hospital 108, Hanoi, Vietnam

Abstract Tissue engineering (TE) of cartilage for reconstructive surgery has proven to be a promising option for obtaining tissue for 3D structures that results in minimal donor site morbidity. Technological advances in this area are important since many defects can only be treated with customized implants. Most TE strategies rely on the use of resorbable 3D scaffolds to guide the growing tissue, with each tissue requiring a specific scaffold that has precisely defined properties depending on the physiological environment. Rapid prototyping (RP) technologies allow the fabrication of scaffolds of various geometric complexities from a variety of materials and as composites, while even allowing the inner architecture of the object to be varied in a defined manner at any given location. Scaffolds can be manufactured using RP techniques directly from computer aided design (CAD) data sources, e.g. via an STL file. The combination of TE and RP serves as the basis for the production of customized implants, for example the cartilage ear framework, and provides new perspectives for autologous Copyright © 2010 S. Karger AG, Basel ear reconstruction.

In head and neck surgery, the successful treatment of various defects, including iatrogenic, traumatic or congenital defects, requires augmentation with supportive tissue. The ideal material is autogenous tissue, but such tissue is only available in a limited supply and is often associated with subsequent donor site morbidity. Furthermore, the transplanted tissue is often inadequate with respect to dimension, shape and function. Tissue engineering (TE) provides a very promising method of overcoming these limitations. Most TE strategies rely on the application of resorbable 3D scaffolds to guide the growing tissue.

Data acquisition

MRI/CT

Computer-aided TE Computer-aided scaffold design

Computer-aided manufacturing

Data processing Tissue culture

Customized TE

Fig. 1. Overview of the steps involved from data acquisition to a customized autologous implant.

Various rapid prototyping (RP) technologies – such as stereolithography, solid freeform fabrication, fused deposition modeling, 3D printing and negative molding – can be utilized in the fabrication of 3D models [1]. Using slice data acquisition through CT or MRI, a defect can be detected and defined according to an exact mathematical model. Then, in combination with data-processing technologies such as computer-aided design (CAD) and computer-aided manufacturing, this procedure can be clinically applied using alloplastic materials, for example as calvarium titanium implants [2]; thus, allowing the generation of the ideal implant for any particular individual defect (fig. 1). However, taking advantage of such state-of-the-art techniques in generating scaffolds for TE using RP is very challenging [3]. The necessary structural features of scaffolds include high porosity, adequate pore size, interconnectivity for cell seeding and nutrient diffusion capabilities. The material must also be non-cytotoxic, and should enable cell adhesion and proliferation. Furthermore, it must provide specific biomechanical stability and elasticity, as well as controlled degradation and resorption rates to match tissue replacement.

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Such customized scaffolds can be seeded with cells of various sources, e.g. with differentiated cells like chondrocytes or periosteal cells for cartilage tissue; preadipocytes for fat tissue; or mesenchymal stem cells for bone, cartilage or tendon TE. Every different type of cell requires optimal material characteristics and seeding strategies in order to generate the desired tissue. For optimal tissue development, specific supplements and growth factors are also essential. In addition, a variety of bioreactors are currently in use to support tissue development and tissue architecture for clinical application. This article provides a overview of the combination of RP and TE in generating individual autologous ear implants.

Imaging Data Acquisition

In order to produce a scaffold with the aid of RP techniques, the basis of the manufacturing process (i.e. the imaging data acquisition) has to be appropriate. This requires that the resolution of the slice images be high enough to adequately represent all the necessary details. However, it must be taken into account that even with today’s most powerful computers such large datasets are still very difficult to process. In principle, setting resolutions on image acquisition scanners like the CT and MRI scanners so they do not natively support image capture, but are instead computed by interpolation, is counter-productive since it impairs data transmission and does not lead to better image quality. Today, very advanced cubical interpolation and filtering algorithms are available, but details that are not contained in the primary image cannot be retrieved or enhanced during subsequent data processing. With respect to the type of image acquisition technology used, the superiority of CT scanners in image resolution and quality is so great that their application is adequate in most cases. This includes the representation of cartilage structures that will be discussed later. Experience shows that slice distances in the range of 1–2 mm, combined with a planar pixel size of 0.5–0.7 mm, are optimal for later reconstruction. Lower values of these parameters do not necessarily lead to significantly better results, but only serve to complicate data processing. This also applies to complex cartilage structures like the concha. However, in this particular case, a high number of tonal values (at least 3,000 unique ones) are additionally needed to ensure proper segmentation later on. The image processing is performed on personal computers, and thus requires that an appropriate data interchange format be chosen. Nowadays, this can be done using DICOM format slice images on CD-R media in most cases. In order to ensure an unobstructed process, images should not be compressed. When using WORM (write once, read many) and MO (magneto-optical) media it must also be considered whether the devices and their associated formats are mostly proprietary to the manufacturer of the scanner. Thus, the compatibility of such devices and media combinations with the data processor should be checked in advance.

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Fig. 2. Data acquisition and processing of a virtual model of the cartilaginous part of the missing contralateral ear.

Imaging-Based 3D Data Processing

After importing the datasets into a PC workstation, they can be processed with special software products that are commercially available. The most common are Mimics from Materialise (Leuven, Belgium) and Amira from Mercury Computer Systems (Chelmsford, Mass., USA). The task of the software is to generate a 3D computer model based on the 2D slice images. Furthermore, the software also provide services such as editing, measuring and direct interfacing to RP machines. It should be noted that in most cases multiple sub-datasets can no longer be combined at this stage. Therefore, the desired regions have to be contained in 1 continuous record. Different tissue types are represented in the scanner images by varying grey values, whereby the segmentation of the target type has to be made by choosing a certain bandwidth. This decision tends to be somewhat intuitive since it depends on the calibration of the imaging equipment and the reconstruction method. Scanning is then automatically performed on all slices present with the same values. On the basis of the resulting mask, a cubical interpolation with subsequent smoothing is carried out to achieve a continuous virtual 3D model. This can be, for instance, either the entire bone structure of the head or only the cartilage portions. In subsequent steps, subsections can also be separated by setting distraction layers. Using this procedure, a model of the existing structures is produced. In order to obtain a scaffold for further processing, the mockup can be used in different ways. In the case of the ear, it can simply be mirrored because of its symmetry and small area of support (fig. 2). If no guide information from the respective patient is available, extrinsic information can be used as a basis for constructing the implant piece-by-piece by means of standard CAD systems like those used in engineering. After completion, the computer model can be exported to one of many data formats used in RP. Common types

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include STL as a 3D exchange format with limited possible resolution, and CLI which is already adapted to the RP machines and thus cannot be subsequently edited.

Customized Scaffold Design and Manufacturing

Scaffolds are 3D biomaterial structures that mimic the function of the natural extracellular matrix within the tissue they should replace [4]. Each tissue requires a specific scaffold with precisely defined properties. The scaffold design depends on the physiological environment which is needed by the donor cells to build a proper tissue. Scaffolds serve as: • an adhesion substrate for the cell, facilitating the localization and delivery of cells when they are implanted; • temporary mechanical support of the newly grown tissue by defining and maintaining a 3D structure; • a guide for the development of new tissue with the appropriate function, e.g. by release of agents such as growth factors. To be successful in TE, scaffolds must fulfill a specific set of requirements, such as biocompatibility, and possess adapted surface and physiochemical properties that promote or inhibit the initial cell attachment. Pore size, interconnectivity and pore morphology are responsible for the homogenous distribution of the cells into the scaffold, and the trouble-free transport of nutrients, metabolites and degradation products which are the basis for tissue formation and vasculature. The mechanical properties have to be in line with the host environment, e.g. load-bearing tissue substitutes for cartilage. Sufficient mechanical strength and stiffness are also required to deal with wound contraction forces and remodeling processes during tissue building and simultaneous scaffold degradation. Finally, an adjustable rate of degradation or a smooth transition between tissue build-up and scaffold degradation, as well as a moderate immunological response to the scaffold material itself and the degradation products, are indispensable in successfully building an effective tissue substitute. A number of different scaffold materials of both natural and synthetic origin and/ or degradable and non-degradable have been investigated, for example: • collagen, hyaluronic acid, fibrin, alginate and Pluronics for cartilage development; • demineralized bone matrix, hydroxylapatite, ceramics, coral and various types of different glass for bone; • polylactic acid, polyglycolic acid, polycaprolactone for bone and cartilage; • poly(ethylene glycol)-terphtalate for human nasal cartilage; • poly(L-lactide-co-glycolide) for nerve TE; • fibrin glue for cartilage and urethral reconstruction. None of the known biomaterials used in TE are ideal for the production of individual cell carriers through RP technologies. Having determined the appropriate material for the desired application, it must be checked whether the material can be processed

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Fig. 3. Newly developed polyurethane material based on polycaprolactone, with 80% porosity and high interconnectivity under electron microscopy.

with the desired macro- and micro-architecture, and whether the material is compatible with the associated technical equipment. To meet the scaffold requirements mentioned previously, TE uses RP techniques. In an attempt to optimize our material properties, we developed a biomaterial based on polycaprolactone as a degradable polyurethane. This foam has 80% porosity, high interconnectivity and open surfaces with excellent biocompatibility for chondrocytes (fig. 3).

Rapid Prototyping RP technologies utilize very specialized processes commonly used in the industrial production of technical equipment, which allow the fabrication of physical objects directly from CAD data sources via STL files. Based on such computer-aided techniques, objects of any geometric complexity can be formed without the need for final assembly. They can be fabricated from a variety of materials and as composites, and the process even allows the inner architecture of the object to be varied in a defined manner at any given location. RP techniques can be easily automated and integrated with imaging techniques to produce scaffolds that are customized in size and shape. In combination with TE, the basis for the production of quality customized implants is assured. There are currently more than 20 different RP techniques being applied in various fields. Solid free-form fabrication is an umbrella term for a variety of different techniques such as stereolithography, selective laser sintering, 3D printing, 3D plotting and fused deposition modeling. These solid free-form fabrication systems permit the fabrication of complex objects via a manageable, straightforward and relatively fast process.

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Table 1. Comparison of different RP techniques used in TE scaffold fabrication for head and neck surgery Resolution μm

Materials

Advantages

Disadvantages

Stereo lithography

70–250

reactive resins, PEG acrylate, PEG methacrylate, polyvinyl acetate, HA, dextran methacrylate, polypropylene fumarate

good mechanical strength, easy to use, easy to achieve small features

limited to reactive resins (mostly toxic), must be photosensitive, extremely dense, low void volume

Selective laser sintering

400–500

bulk polymers, polyethylene, ceramics, metals, compounds, PEEK, polyvinyl alcohol, PCL, polylactic acid, HA

high accuracy, high porosity, good mechanical strength, broad range of bulk materials, no support structure needed, fast processing

material must be in powder form, elevated temperatures from local high-energy input, uncontrolled porosity, material shrinkage when sheet-like structure is made, resolution depends on the laser beam diameter, powder may be trapped

3D Printing

100–500

ink and powder of bulk, polymers, PLGA ceramics, starch, dextran, gelatine

no inherently toxic components, fast processing, low costs, high porosity, can be performed in an ambient environment

weak bonding between powder particles, diminished accuracy, rough surface, component resolution and efficiency of removal of trapped materials are concerns

3D Plotting

100–250

swollen polymers (hydrogels), thermoplastic polymers, reactive resins, ceramics, PBT, PEOT

broad range of materials, broad range of conditions, incorporation of cells, protein fillers

slow processing, low accuracy, limited resolution, low mechanical strength, no standard condition, time-consuming adjustment to new materials

Fused deposition modelling

160–700

thermoplastic with good melt viscosities polymers/ceramics, PCL, PP-TCP, PCL-HA, PCL-TCP, PEGT-PBT

low costs, no trapped particles or solvents, highly reproducible, fully interconnected pore network, variation of pore morphology across scaffold realizable, input material in pellet form, preparation time is reduced

elevated temperatures, range of bulk materials limited by melting point and processing conditions, no natural materials, medium accuracy, positive value for pore channels is applied, high temperature, rigid filament, pore heights are determined by size of polymer fiber, no incorporation of biomolecules

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Table 1. Continued

Injection molding (high pressure at high temperature; low pressure at room temperature)

Resolution μm

Materials

Advantages

Disadvantages

135–500

hydrogel, PCL, polyester, collagen, ceramics, PLGA

broad range of materials, low pressure/room temperature, high accuracy, complex shapes and defined wall thickness can be fabricated reproducibly, can be automated

concerning compression molding: thermal degradation of polymers, no defined porosity and wall thickness, skin formation on polymer surface

PEG = Poly(ethylene glycol); PEEK = polyaryletheretherketone; PCL = polycaprolactone; PLGA = poly(lactic-co-glycolic acid); PBT = polybutylene terephthalate; PEOT = polyethylen oxid terephthalate; HA = hyaluronic acid; TCP = tricalcium phosphate.

By applying the expertise of RP techniques to medical scaffold production, most of the macro- and micro-architectural requirements for TE applications can be satisfied. In particular, the proper micro-architectural design of the scaffold is critical in order to ensure the required discharge of nutrients and oxygen not only on the surface, but also throughout the inner areas of the scaffold. However, each of the RP technologies currently available has its individual strengths and weaknesses (table 1), and all are highly specific with respect to the processability of particular materials. Not all scaffold materials can be processed with all of the types of RP equipment, which results in a significant reduction in the availability of suitable biomaterials. This means that the planning of any scaffold production must first take into account whether or not the desired biomaterial is available in the required form, such as solid pellet, powder, filament or solution. The next question is whether the characteristic material properties, e.g. biocompatibility, are affected by such production process as solidification, heating, etc. It must also be ensured that the choice of scaffold materials is compatible with the selected RP technique, and that it is possible to fabricate the scaffold in the required way.

Injection Molding Injection molding is a very widely used technique for the manufacturing of a variety of parts, from the smallest component to entire body panels of automobiles. TE scaffolds are fabricated by using molds, which can be fabricated from a CAD data file by STL or 3D printing, e.g. from metal, ceramic or silicone [5]. Liquid material is injected into a mold that is the inverse of the desired shape [6].

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Fig. 4. The mold for producing scaffolds with 2-component foaming of the polyurethane.

Fig. 5. Individual scaffold (a) after seeding with chondrocytes and a cultivation period of 4 weeks (b).

a

b

In principle, there are 2 different types of injection molding: – molding of liquefied materials with high compression and high temperature; – molding at low pressure and room temperature. Molding at low pressure and low temperature is characterized by high reproducibility, automatization and production efficiency. It enables the use of a number of biomaterials that are not compatible with the fabrication processing conditions of many of the previously mentioned techniques. Complex-shaped porous scaffolds, as well as tubular scaffolds with thin walls and small diameters, can be produced at a resolution of up to 135–500 μm [7]. We developed a specific mold for generating complex polyurethane scaffolds (fig. 4). After data acquisition, data processing and the production of the desired scaffold

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using RP technology, the mold must be vitalized by cell seeding, which represents the cellular part of TE.

Tissue Engineering

According to Langer and Vacanti [8], TE is defined as: ‘an interdisciplinary field that applies the principles of engineering and the life sciences toward the development of biological substitutes that restore, maintain or improve tissue function’. To produce viable tissues, TE uses strategies [9] such as the: • implantation of the isolated cells directly into the defect (cell-based therapy); • implantation of a bioactive scaffold material that implements the ingrowth of the desired tissue (e.g. joint repair, implantation of scaffold material, or stem cells that migrate into the scaffold and rebuild bone or cartilage); • implantation of a cell/scaffold combination. These attempts should improve or even replace standard biological functions. Differentiated autologous cells are highly specialized cells that are characteristic of each single tissue with a clearly defined function, e.g. chondrocytes for cartilage. However, using these cells for building substitute tissues results not only in the reduction of the limited mass of the donor tissue, but also in undesirable collateral tissue damage. A further serious problem is that the differentiated cells, when taken out of the normal 3D environment, tend to dedifferentiate in the 2D cell culture environment within a few days. Dedifferentiation means that they are not producing a tissuespecific matrix, but that they change their morphology and, after a longer period of time, even their genotype. To achieve and maintain their typical cell qualities, cells have to be cultured in an appropriate 3D environment or scaffold. Cells such as cartilage cells, keratinocytes and muscle cells proliferate rapidly. Others cells, such as hepatocytes and cardiomyocytes, proliferate slowly or not at all. Therefore, alternative sources of cells, like stem cells, are often needed.

Cell Seeding Single cells can be dropped, injected or sucked as a highly concentrated cell suspension onto and into a scaffold, assuming that the force of gravity will subsequently disperse the cells throughout the entire thickness of the scaffold (fig. 5). However, this strategy is often associated with cell loss. Cells can fall through the pores into the culture dish or they may not necessarily penetrate into the scaffold due to insufficient interconnectivity or hydrophobic surfaces. Another possibility for cell seeding is the encapsulation of cells, known as macrocapsules, mircocapsules and 3D multicellular masses, into hydrogels e.g. fibrin glue alginate, type I collagen, methylcellulose or pluronic F127. These particles can then

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either be subsequently seeded onto the material scaffold directly or the hydrogel/cell particles are shaped by a 3D plotter. Cell culture additives, like growth factors, are also a major concern in TE. Growth factors are defined as proteins that act as signaling molecules between cells, attach to specific receptors on the surface of a target cell, and promote differentiation and maturation of these cells. All kinds of growth factors are used in TE, such as insulinlike growth factor, transforming growth factor β, or interleukin for cartilage TE [10]. Future goals of TE are the enhanced development of customized TE products to avoid the problems of reducing limited donor tissue, creating collateral tissue damage and unwanted immune responses. To this end, the in vitro culture of cells must be improved so that cell dedifferentiation can be inhibited. In the attempt to establish co-cultures of different cells, the development of bioreactors that enable the co-culture of specifically sized implants has to be ensured. Computer-aided TE will become increasingly important in the future to enable the development of customized scaffolds using the appropriate techniques, materials, and micro- and macro-architectures, without the loss of geometrical resolution, accuracy in detail or material properties such as biocompatibility.

Conclusion

The combination of TE and RP enables us to take the next step in regenerative medicine, i.e. the fabrication of customized implants. Customized implants are designed by the defect data gained from medical imaging technologies, transferred into the language of RP machines, and then realized as a biomaterial scaffold. These individualized scaffolds (such as those used in ear reconstruction) can be seeded with autologous cells, and, after just a short period of time, implantation of the ‘individually customized’ implant can take place.

Acknowledgments Our work was supported by the Bayerische Forschungsstiftung within the FORTEPRO (Az.: 442/01) project and the International Science Exchange Program (PIZ 17/03).

References 1 Staudenmaier R, Naumann A, Bruning R, Englmeier KH, Aigner J: Ear reconstruction supported by a stereolithograpical model. Plast Rec Surg 2000;106:511–512. 2 Dean D, Min KJ, Bond A: Computer aided design of large-format prefabricated cranial plates. J Craniofac Surg 2003;14:819–832.

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3 Hutmacher DW, Schantz T, Zein I, Ng KW, Teoh SH, Tan KC: Mechanical properties and cell cultural response of polycaprolactone scaffolds designed and fabricated via fused deposition modeling. J Biomed Mater Res 2001;55:203–216.

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4 Yeong WY, Chua CK, Leong KF, Chandraselaran M: Rapid prototyping in tissue engineering: challenges and potential. Trends Biotechnol 2004;22:643–652. 5 Chang S, Tobias G, Roy A, et al: Tissue engineering of autologous cartilage for craniofacial reconstruction by injection molding. Plast Reconstr Surg 2003; 112:793–801. 6 Gomes ME, Ribeiro AS, Malafaya PB, Reis RL, Cunha AM: A new approach based on injection moulding to produce biodegradable starch-based polymeric scaffolds: morphology, mechanical and degradation behaviour. Biomaterials 2001;22:883– 889.

7 Sachlos E, Czernuszka JT: Making tissue engineering scaffolds work. Review: the application of solid free form fabrication technology to the production of tissue engineering scaffolds. Eur Cell Mater 2003; 5:29–39, discussion 39–40. 8 Langer R, Vacanti JP: Tissue engineering. Science 1993;260:920–926. 9 Arosarena O: Tissue engineering. Curr Opin Otolaryngol Head Neck Surg 2005;13:233–241. 10 Richmon JD, Sage AB, Shelton E, Schumacher BL, Sah RL, Watson D: Effect of growth factors on cell proliferation, matrix deposition, and morphology of human nasal septal chondrocytes cultured in monolayer. Laryngoscope 2005;115:1553–1560.

Staudenmaier Rainer, MD Department of ENT and Head and Neck Surgery, Technische Universität Munich, Klinkum rechts der Isar Ismaninger Strasse 22 DE–81675 Munich (Germany) E-Mail [email protected]

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Author Index

Berghaus, A. 53 Blunk, T. 120 Burghartz, M. 120

Mandlik, V. 120 Meier, G. 120 Naumann, A. 53

Federspil, P.A. 65 Firmin, F. 25 Haisch, A. 108 Hauber, K. 120 Hempel, J.M. 53 Hoang, N.T. 120 Kadegge, G. 120 Kiefer, J. 81

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Schurr, C. 120 Siegert, R. 95 Staudenmaier, R. VI, 81, 120 Stelter, K. 53 Weerda, H. 1

Subject Index

Active middle ear implant, see Functional/ esthetic ear reconstruction Ankylos® system 69 Atresia, see Combined auricular atresia and microtia, Functional/esthetic ear reconstruction Brånemark system 69 Brent’s technique 18, 20 Cartilage, see Microtia, Rib cartilage, Tissue engineering Combined auricular atresia and microtia histology of reconstruction 101–103 overview 95, 96 postoperative treatment and follow-up 101 preoperative diagnostics 96 reconstructive surgery first operation 96, 97 outcomes 102–106 principles of 3-step procedure 104 second operation 97–99 third operation 100, 101 Computed tomography, see Rapid prototyping Epiplating® system 70 Epitec® system 70 Facial nerve, monitoring in surgery 93 Floating mass transducer active middle ear implants 82 implantation, see Functional/esthetic ear reconstruction Full-thickness spindle-shaped skin graft, combined auricular atresia and microtia reconstruction 97, 99–101, 104

Functional/esthetic ear reconstruction active middle ear implants 82, 86 auricle reconstruction and implant bed preparation 85, 87 ear canal creation 92 facial nerve monitoring 93 floating mass transducer coupling to inner ear fluid 83 coupling to vibratory structures 88 round window stimulation 83 hearing outcomes 89, 91, 92 microtia and hearing loss 81, 82 middle ear access 87 overview of technique 84 patients characteristics 88–90 etiology and operative procedures 89, 90 preparation 84, 85 preliminary considerations 84 sequelae 92 Gavello flap 8 Historical perspective, auricular reconstruction overview 53, 54 partial reconstruction ancient sources 1, 2 composite grafts 10 1400–1500s 3, 4 prosthesis 4, 5 reconstruction with auricular reduction 4–6 reconstruction without auricular reduction 4, 6–9 skin expansion 14, 16

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temporoparietal fascial flap 11, 12 tubed flaps 9, 10 replantation 21 total reconstruction Brent’s technique 18, 20 Nagata’s technique 19, 20 pre-1950 14–16 Tanzer’s reconstruction 17, 18, 20 Infection, autogenous reconstruction complication in microtia 46, 47 Injection molding, tissue engineering scaffolds 127–129 ITI® system 69 Magnetic resonance imaging, see Rapid prototyping Malleus-incus complex, combined auricular atresia and microtia reconstruction 98, 102, 105 Microtia, autogeneous reconstruction atresia combination, see Combined auricular atresia and microtia cartilaginous framework rib cartilage harvesting 26, 27 sculpturing 26–30 skin approach for implantation clinical examples of types 33–38 selection of type 39–43 type 1 32 type 2 32, 33 type 3 33–35 complications exposure 47–50 infection 46, 47 elevation of reconstructed ear 44, 45 grading of outcomes 50, 51 middle ear reconstruction, see Functional/ esthetic ear reconstruction outcomes 45, 46 overview 25, 26 prosthesis and patient management 78 Middle ear reconstruction, see Functional/ esthetic ear reconstruction

Porous polyethylene ear reconstruction bandages 62 complications 62, 63 indications 57 insertion of implants 61 sculpturing and preparation of implants 59–61 skin covering 61, 62 surgical technique 59 technical preparations 57–59 overview of properties 55–57 Prefabricated external ear canal, combined auricular atresia and microtia reconstruction 99–101, 104, 105 Prefabricated tympanic membrane, combined auricular atresia and microtia reconstruction 99–101, 104, 105 Prosthesis advantages and disadvantages 77 complications of surgery 76 contraindications for surgery 76 definition 65 historical perspective 4, 5, 65, 66 implant systems Ankylos® system 69 Brånemark system 69 Epiplating® system 70 Epitec® system 70 ITI® system 69 overview 68, 69 materials 66 osseointegration 68 outcomes of surgery 73–76 rehabilitation by population cancer 78, 79 children 77, 78 microtia 78 trauma 78 retention techniques 66–68 surgical technique bone trauma minimization 71 grouped implant systems 72 implant positioning 71 solitary implant systems 72

Nagata’s technique 19, 20 Partial ossicular replacement prosthesis, combined auricular atresia and microtia reconstruction 99, 102

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Rapid prototyping custom scaffold design and manufacturing 125–127 imaging data acquisition 122, 123

Subject Index

overview 121, 122 three-dimensional data processing 123, 124 Rib cartilage alternatives, see Porous polyethylene disadvantages 54, 55 harvesting 26, 27 sculpturing 26–30 Superficial temporalis fascia, combined auricular atresia and microtia reconstruction 98, 99, 103 Tanzer’s reconstruction 17, 18, 20 Temporal artery exposure 59 imaging 59 Temporal parietal fascia, ear reconstruction with porous polyethylene 59, 61, 62 Tissue engineering, cartilage cartilage characteristics 109, 110 cell seeding 129, 130

Subject Index

chondrocyte preparation 110, 111 collagen expression 111 implant characteristics in vivo 114–116 injection molding of scaffolds 127–129 prospects 116 rapid prototyping for implant customization custom scaffold design and manufacturing 125–127 imaging data acquisition 122, 123 overview 121, 122 three-dimensional data processing 123, 124 regenerative capacity of humans 108, 109 scaffold materials 111–113 three-dimensional framework design 113, 114

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