THE HANDBOOK OF C-ARM FLUOROSCOPY-GUIDED SPINAL INJECTIONS
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THE HANDBOOK OF C-ARM FLUOROSCOPY-GUIDED SPINAL INJECTIONS
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HANDBOOK OF C-ARM FLUOROSCOPY-GUIDED SPINAL INJECTIONS Linda hong wang Anne Marie McKenzie-Brown Allen H. Hord
Boca Raton London New York
A CRC title, part of the Taylor & Francis imprint, a member of the Taylor & Francis Group, the academic division of T&F Informa plc.
Published in 2006 by CRC Press Taylor & Francis Group 6000 Broken Sound Parkway NW, Suite 300 Boca Raton, FL 33487-2742 © 2006 by Taylor & Francis Group, LLC CRC Press is an imprint of Taylor & Francis Group No claim to original U.S. Government works Printed in the United States of America on acid-free paper 10 9 8 7 6 5 4 3 2 1 International Standard Book Number-10: 0-8493-2254-5 (Hardcover) International Standard Book Number-13: 978-0-8493-2254-9 (Hardcover) Library of Congress Card Number 2005051403 This book contains information obtained from authentic and highly regarded sources. Reprinted material is quoted with permission, and sources are indicated. A wide variety of references are listed. Reasonable efforts have been made to publish reliable data and information, but the author and the publisher cannot assume responsibility for the validity of all materials or for the consequences of their use. No part of this book may be reprinted, reproduced, transmitted, or utilized in any form by any electronic, mechanical, or other means, now known or hereafter invented, including photocopying, microfilming, and recording, or in any information storage or retrieval system, without written permission from the publishers. For permission to photocopy or use material electronically from this work, please access www.copyright.com (http://www.copyright.com/) or contact the Copyright Clearance Center, Inc. (CCC) 222 Rosewood Drive, Danvers, MA 01923, 978-750-8400. CCC is a not-for-profit organization that provides licenses and registration for a variety of users. For organizations that have been granted a photocopy license by the CCC, a separate system of payment has been arranged. Trademark Notice: Product or corporate names may be trademarks or registered trademarks, and are used only for identification and explanation without intent to infringe. Library of Congress Cataloging-in-Publication Data Wang, Linda H. (Linda Hong) Handbook of C-arm fluoroscopy-guided spinal injections / Linda H. Wang, Anne Marie McKenzieBrown, Allen Hord. p. cm. Includes bibliographical references and index. ISBN 0-8493-2254-5 (alk. paper) 1. Injections, Spinal--Handbooks, manuals, etc. 2. Diagnosis, Fluoroscopic--Handbooks, manuals, etc. 3. Spine--Puncture--Handbooks, manuals, etc. 4. Chronic pain--Treatment--Handbooks, manuals, etc. I. McKenzie-Brown, Anne Marie. II. Hord, Allen. III. Title. RC400.W32 2006 615'.6--dc22
2005051403
Visit the Taylor & Francis Web site at http://www.taylorandfrancis.com Taylor & Francis Group is the Academic Division of T&F Informa plc.
and the CRC Press Web site at http://www.crcpress.com
Dedication To our spouses, without whose love, support, and patience this handbook would not have been possible. To our children, anything is possible if you put your mind and heart to it. To our parents, who taught us to believe in ourselves, to aim past the limits, to never give up, and to make each day count.
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Acknowledgments To Dr. James R. Zaidan, our department chairman, and Dr. Peter Sebel, our vice chairman, for believing in and supporting us, as well for their dedication to graduate medical education. To Dr. Jay Johansen for the many hours that he dedicated to helping us with the computer software that made possible the images used throughout this book. To Drs. Randy Rizor, John Porter, and Charles McNeill for teaching spinal injections. To Ms. Rochelle Lewis, who was a great help with proofreading. To Mr. Jeannette Ramos, whose tireless dedication helps to make our practice run smoothly. To Mrs. Sophia Rosene whose mastery of x-ray skills proved invaluable. To former and current pain fellows, with particular thanks to Dr. Talal Khan and Dr. Brannon Frank, for special assistance in the fluoroscopy images and computer editing. Your pursuit of knowledge was instrumental in our academic growth as well. To our pain colleagues, Drs. Patricia Baumann and Michael Byas-Smith, for supporting us in this project. And perhaps last, but certainly not least, to our patients, who give us their trust and, occasionally, restore our faith in ourselves.
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Preface C-arm fluoroscopy-guided spinal injections have been performed widely for diagnosis and management of spine and para-spinal-related pain disorders. So often, residents and pain fellows do not receive formal training in radiography and the related anatomy of the vertebral column. The purposes of this handbook are to (a) illustrate spinal injections in a step-by step fashion, (b) present fluoroscopy imaging and related spinal anatomy, and (c) describe manipulation of C-arm fluoroscopy to get ideal images for spinal injections. The concept of this book started off as a compilation of notes and lectures that were put together for the educational benefit of our pain fellows as well as those residents who rotate on the pain service. The residents spend 2 months on the service and often have a difficult time orienting themselves to the C-arm and the resulting fluoroscopic images. While there are now quite a few books on the market that show the final needle position for spinal injections, we felt that there was a need for a book describing a more basic, step-by-step approach to spinal injections. As a pain fellow, Dr. Linda Wang started collecting images and teaching tools to help her better understand the reasoning behind the fluoroscopic images that were used for spinal injections. As a faculty member, Dr. Wang spent a tremendous amount of time studying the relationships between the skeletal model, the matching fluoroscopic image, and the desired needle placement in the cervical, lumbar, and sacral spinal regions. There is often a skeleton hanging prominently in the procedure room that is used as a reference when we perform fluoroscopically guided injections. Dr. Wang sought to recreate those images in her chapters that effectively demonstrate the relationships between the angle of the x-ray beam and the spinal column. In the chapters describing the fluoroscopic imaging of the cervical, lumbar, and sacral spine, Dr. Wang describes in detail how the trainee would go about obtaining the views needed to approach the spine at each level. Dr. McKenzie-Brown has long had an interest in the cervical spine and procedures performed around the cervical spine as well as in lumbar discography. The neck houses critical vascular structures that affect the way in which injections around the cervical spine are performed. The chapters that she wrote pertaining to cervical injections show a safe method for performing these injections under fluoroscopy. As our program became more interventional in the management of pain, Dr. McKenzie-Brown became more interested in radiation safety, and the basic tenets of radiation safety are succinctly described in Chapter 3. Finally, the sympathetic chapters are left as a category unto themselves. Until fairly recently, stellate and lumbar sympathetic injections were routinely performed without fluoroscopy. Dr. Wang takes us through step-by-step approaches to each of the sympathetic blocks with insights into how to ascertain the correct needle position at each level. Dr. Wang was encouraged by Dr. Allen H. Hord to enter the area of pain medicine. Dr. Hord served as a motivator and educator in the training of Dr. Wang and countless other physicians in the area of C-arm fluoroscopic techniques. His review of this handbook proved to be an invaluable asset.
Each of the spinal injections in this handbook is simply written. The preferred patient’s position as well as C-arm fluoroscopy position, preferred fluoroscopic images, and related anatomic structures on the spine are described. The steps taken to get to the final placement of the needle tip are also described. Not only are the correct needle placements illustrated from different views of the spine, but possible incorrect needle placements are shown as well. We endeavored to provide a handbook that will become a useful teaching aid for residents and fellows striving to improve their skills in the performance of spinal injections for pain management.
The Authors Linda Hong Wang, M.D., Ph.D., graduated from Capital University of Medical Sciences (Beijing Second Medical College) in Beijing, China. She then came to the United States and studied basic science in pain medicine at the University of Illinois in Chicago. After she received her Ph.D., she continued her training in anesthesia at the Mayo Clinic in Rochester, Minnesota. She completed her anesthesiology residency at Emory University School of Medicine, following which she spent 12 additional months there in her pain fellowship. She is currently working in Emory’s Department of Anesthesiology in Atlanta, Georgia.
Anne Marie McKenzie-Brown, M.D., graduated from Johns Hopkins School of Medicine and completed her anesthesiology residency at Emory Healthcare. After spending a year in pain fellowship training at the Johns Hopkins Department of Anesthesiology, she returned to Emory Department of Anesthesiology, where she remains on faculty. She is currently the director of the Division of Pain Medicine and the director of the Pain Fellowship Program at the Emory Department of Anesthesiology in Atlanta, Georgia. Dr. McKenzie-Brown earned her undergraduate degree in chemistry at the University of Virginia in Charlottesville. She went to Baltimore and completed her doctorate of medicine at Johns Hopkins School of Medicine. After completing a year of internship in internal medicine at St. Luke’s/Roosevelt Hospital, she came to Atlanta and completed an anesthesiology residency at the Emory Department of Anesthesiology. She then returned to Baltimore and spent 1 year in the Department of Anesthesiology and Critical Care in fellowship training in pain medicine and as an assistant in the Division of Regional Anesthesia. Following that, she came back to Atlanta as a staff anesthesiologist in the Emory Department of Anesthesiology, dividing her time between clinical anesthesiology and pain medicine. She was the director of the Grady Pain Clinic between 1995 and 2003, the clinical director of the Emory Center for Pain Medicine in 2002, and the division director of Pain Medicine the following year. In 2004, she became the program director for the Emory Pain Fellowship. Dr. McKenzie-Brown is board certified in anesthesiology and earned the Certificate of Additional Qualifications in Pain Management. She is also board certified by the American Board of Pain Medicine. Her interests include spinal pain, with special interest in cervical spinal pain and sacroiliac joint pain.
Allen H. Hord, M.D., is a practicing pain consultant with Pain Consultants of Atlanta. He also holds an adjunct appointment as clinical associate professor of anesthesiology at Emory University School of Medicine in Atlanta, Georgia. Dr. Hord earned his B.A. in chemistry and molecular biology at Vanderbilt University in Nashville, Tennessee, and his M.D. at the University of Kentucky School of Medicine in Lexington, Kentucky. After graduating, he completed his internship at Grady Memorial Hospital in Atlanta, Georgia, and his residency in anesthesiology at Emory University School of Medicine. His fellowship in pain was conducted at the University of Cincinnati Pain Control Center in Cincinnati, Ohio. He is certified by the American Board of Anesthesiology and was awarded a Certificate of Added Qualifications in Pain Management. Dr. Hord is also certified by the American Board of Pain Medicine. Dr. Hord was formerly director of the Center for Pain Medicine, director of the Division of Pain Medicine, and program director of the Pain Management Fellowship at Emory University School of Medicine. Dr. Hord’s current research is devoted to the study of neuropathic pain. He has authored and coauthored more than 62 articles, abstracts, editorials, books, book chapters, book reviews, review articles, and case reports concerning topics in pain management.
Table of Contents Chapter 1.
An Introduction to Spinal Injections.....................................................1
Chapter 2. Basic Radiographic Background of the Vertebral Column ...................5 C-Arm Fluoroscopy and Images........................................................................................................7 Axial Skeleton..................................................................................................................................13 Anatomy of a Typical Lumbar Vertebra ....................................................................................15 Pelvic Girdle and Sacrum ...........................................................................................................17 Classification of Bones and Typical Fluoroscopic Images of Bones .............................................18 Bibliography.....................................................................................................................................27 Chapter 3. Radiation Safety ................................................................................29 Quantification of Radiation Exposure .............................................................................................31 Steps to Minimize Radiation Exposure ...........................................................................................32 Shielding...........................................................................................................................................39 Bibliography.....................................................................................................................................39 Chapter 4. Basic Steps for Spinal Injections .......................................................41 Bibliography.....................................................................................................................................54 Chapter 5. Fluoroscopic Images of the Lumbar Spine ........................................55 Positioning the Patient .....................................................................................................................57 Anterior/Posterior View of the Lumbar Spine ................................................................................57 Oblique View of the Lumbar Spine.................................................................................................59 Lateral View of the Lumbar Spine ..................................................................................................62 Suggestions on How to Check the Needle Depth...........................................................................67 Bibliography.....................................................................................................................................69 Chapter 6. Lumbar Spinal Injections ...................................................................71 Lumbar Spinal Injections.................................................................................................................73 Lumbar Medial Branch Block .........................................................................................................73 Lumbar Medial Branch Denervation ..........................................................................................87 Lumbar Transforaminal Epidural Steroid Injection ........................................................................88 Special Considerations of Oblique Views ..................................................................................94 Rules for Getting Oblique Views of the Lumbar Spine..................................................................95 Lumbar Transforaminal Epidural Steroid Injection at the Level of L5/S1 .....................................................................................................................111 Lumbar Discography......................................................................................................................124 Introduction ...............................................................................................................................124
Manometry .....................................................................................................................................127 Patient Preparation ....................................................................................................................127 Sedation .....................................................................................................................................127 Preparation for Needle Placement .......................................................................................128 Patient Position..........................................................................................................................128 C-Arm Position .........................................................................................................................129 Needle Placement......................................................................................................................130 Potential Difficulties with Needle Placement (Annular Placement of the Needle) ..........................................................................................132 Contrast Injection within the Disc Space .................................................................................136 Mechanically vs. Chemically Sensitive Discs ..........................................................................141 Discography at L5/S1 ....................................................................................................................141 Positioning C-Arm Fluoroscopy ...............................................................................................142 Needle Insertion ........................................................................................................................142 Confirming the Needle Placement ............................................................................................145 Injecting Contrast ......................................................................................................................146 Post-Procedure ...............................................................................................................................147 Bibliography...................................................................................................................................148 Chapter 7. Fluoroscopic Images of the Cervical Spine .....................................151 Positioning the Patient ...................................................................................................................153 Positioning the C-Arm Fluoroscopy..............................................................................................154 A/P (P/A) View and Lateral View of the Cervical Spine .............................................................155 Comparison of Cervical Vertebrae and Lumbar Vertebrae ...........................................................156 Lateral and Oblique Views of the Cervical Spine.........................................................................158 Cervical Intervetrebral Foramina and the Cervical Spinal Nerve Roots ......................................165 Bibliography...................................................................................................................................167 Chapter 8. Cervical Injections ...........................................................................169 Preparation for the Performance of Cervical Injections ...............................................................171 Cervical Facet Injections ...............................................................................................................172 Intra-Articular Facet Injections......................................................................................................174 C1/C2 Joint Injection ................................................................................................................174 C2/C3 to C6/C7 Intra-Articular Joint Injections ......................................................................180 Cervical Medial Branch Injections ...........................................................................................186 Cervical Medial Branch .................................................................................................................191 Radiofrequency Denervation.....................................................................................................191 Radiofrequency Denervation: (C3 to C8) Medial Branches ....................................................192 Cervical Epidural and Selective Nerve Root Injections................................................................196 Cervical Transforaminal Injections...........................................................................................196 C2 Dorsal Root Ganglion Injection..........................................................................................198 C3 to C7 Transforaminal Injections .........................................................................................201 Selective Nerve Root Injection or Epidural Steroid Injection .................................................210 Interlaminar Epidural Steroid Injections ..................................................................................216 Bibliography...................................................................................................................................218 Chapter 9. Fluoroscopic Images of the Sacrum and Pelvis...............................221 Posterior View of the Pelvis and the Sacrum................................................................................223 A/P View of Fluoroscopic Image of the Sacrum ..........................................................................224 Bibliography...................................................................................................................................228
Chapter 10. Pelvic and Sacral Injections...........................................................229 Sacroiliac Joint Injection ...............................................................................................................231 Caudal Epidural Steroid Injection .................................................................................................238 Bibliography...................................................................................................................................246 Chapter 11. Sympathetic Blocks.......................................................................247 Stellate Ganglion Block (Right Side)............................................................................................249 Lumbar Sympathetic Block ...........................................................................................................253 Superior Hypogastric Plexus Block...............................................................................................261 Bibliography...................................................................................................................................267 Index...............................................................................................................................................269
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Chapter
An Introduction to Spinal Injections
1
1
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An Introduction to Spinal Injections
3
In 1994, the International Association for the Study of Pain (IASP) defined pain as “an unpleasant sensory and emotional experience associated with actual or potential damage or described in terms of such damage.” Spinal pain is still a leading cause of disability in the industrialized world. Spinal injections are common procedures for both the diagnosis and treatment of pain related to the spine. This book utilizes a step-by-step approach to illustrate routinely performed fluoroscopically guided spinal injections and procedures at the cervical, thoracic, and lumbosacral regions. This is done in an attempt not only to introduce trainees to the basic interventional techniques but also to assist instructors in their pursuit of demonstrating the techniques of spinal injections in a clear and simple manner. All of the commonly performed spinal injections involve placing the needle in or around the vertebral column. Mastery of the technique of spinal injections involves learning where along the spine to place the needle. Figure 1.1 and Figure 1.2 demonstrate the wide variety of spinal injections that are commonly performed in pain practices. Figure 1.1 represents the axial view, while Figure 1.2 shows the oblique view of the spinal column. Transforaminal epidural steroid injection
Medial branch block
Interlaminar epidural steroid injection Discography
Lumbar sympathetic block FIGURE 1.1 Axial view of needle placements for spinal injections.
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Transforaminal epidural steroid injection
Intraarticular facet injection
Medial branch block
Lumbar sympathetic block Discography
Interlaminar epidural steroid injection
FIGURE 1.2 Oblique view of needle placements for spinal injections.
We will guide readers in a step-by-step fashion through injections commonly performed around the cervical spine, including intra-articular cervical facet and medial branch injections, radiofrequency ablations, and cervical transforaminal and interlaminar epidural steroid injections. Chronic pain is among the most common forms of low back pain that we entcounter in our practice. We will help readers to understand the details of commonly performed lumbar spinal injections, such as lumbar media branch block and transforaminal epidural steroid injection. The more commonly performed procedures in the sacral region that we will discuss include sacroiliac and caudal injections. We will also describe commonly performed sympathetic blocks including stellate ganglion blocks, lumbar sympathetic blocks, and performance of the superior hypogastric plexus block.
Chapter
Basic Radiographic Background of the Vertebral Column
2
5
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Basic Radiographic Background of the Vertebral Column
7
It is essential to be familiar with fluoroscopic images and related anatomy of the human vertebral column in order to perform spinal injections. In this chapter we will go over basic fluoroscopic images of human bones, including human vertebrae.
C-Arm Fluoroscopy and Images A C-arm fluoroscope consists of an x-ray tube, a C-arm arch, an image intensifier, a control panel with a footswitch, and a computerized image display system (Figure 2.1). In C-arm fluoroscopy, a fluoroscopic beam, usually coming from below, penetrates the spine, sending an image to the intensifier. The image is then displayed on a TV screen for review (Figure 2.2). The C-arm can be rotated in different directions in order to view an object from different angles (Figure 2.3). The control panel allows us to adjust how images are generated and displayed by pressing function keys. The footswitch, also part of the control panel, offers more flexibility. The image system not only displays fluoroscopic photos but also stores fluoroscopic images for review and comparison.
Intensifier
Image display system
Control panel
Footswitch FIGURE 2.1 Photograph of a C-arm.
X-ray tube
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A short bone
The short bone is placed between the x-ray tube and the intensifier
The fluoroscopic photo is displayed on the TV screen
A fluoroscopic image of the short bone
FIGURE 2.2
Basic Radiographic Background of the Vertebral Column
FIGURE 2.3 C-arm rotations.
9
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Handbook of C-Arm Fluoroscopy-Guided Spinal Injections
A photograph (Figure 2.4) and a fluoroscopic image (Figure 2.5) are both two-dimensional pictures. However, each has striking differences. Because our goal is to inject appropriate medications in or around the target areas of the spine, it is essential to understand the fluoroscopic images of the spine and the relationship between needle placement and the target area.
FIGURE 2.4 Regular picture of the spine, anterior view.
FIGURE 2.5 Fluoroscopic photo of the lumbar spine.
Basic Radiographic Background of the Vertebral Column
11
A fluoroscopic image of a cylinder from the side, for example (Figure 2.6), is a rectangularshaped image regardless of the angle of the beam. We cannot view the cylinder from the ends. The TV screen of C-arm fluoroscopy is only able to display one image at a time. By reviewing a series of images of this object (Figure 2.7), we are able to mentally construct a three-dimensional picture of this cylinder.
X-ray tube
A cylindrical object FIGURE 2.6 Fluoroscopy does not show a 3-D picture.
X-ray tube
X-ray tube
A cylindrical object X-ray tube
FIGURE 2.7 Creating 3-D images mentally.
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If the fluoroscopic beam goes through a cube (Figure 2.8), the TV screen displays a square. However, we are unable to identify the properties of this cube.
A cube
A fluoroscopic image of the cube
FIGURE 2.8
If a cylinder is placed on top of the cube, a fluoroscopic picture is merely a square with a circle in the middle (Figure 2.9). We are unable to judge the exact relationship between the cylinder and the cube.
A cylindrical object A cube
A fluoroscopic image of the cylindrical object and the cube FIGURE 2.9
Basic Radiographic Background of the Vertebral Column
13
A fluoroscopic picture of these objects (Figure 2.10) is complicated. We cannot describe their exact relationships without adding another picture of these objects from a different view.
A fluoroscopic image of three objects
FIGURE 2.10
The basic steps of a fluoroscopy-guided spinal injection include the following (see Chapter 4 for details): 1. 2. 3. 4. 5.
Identifying a target point in the area of the spine or the pelvis Obtaining fluoroscopic images Inserting a needle Verifying correct needle placement by using the fluoroscopic images Injecting the appropriate medication into the target area
It is important to review the anatomy of the vertebral column and the anatomy of the pelvic girdle.
Axial Skeleton There are 206 separate bones that form the adult human skeletal system — the framework of the entire human body. The adult skeletal system is divided into the axial skeleton and the appendicular skeleton. The axial skeleton has a total of 80 bones that lie on or near the central axis of the human body, including the skull, vertebral column, ribs, and sternum. The vertebral column (Figure 2.11) consists of 26 vertebrae and includes 7 cervical vertebrae, 12 thoracic vertebrae, 5 lumbar vertebrae, 1 sacrum, and 1 coccyx.
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Axial skeleton (total 80 pieces) — Skull — Hyoid — Auditory ossicles • Cervical (7)
— Vertebral column
• Thoracic (12)
— Thorax
• Lumbar (5) • Sacrum (1) • Coccyx (1)
FIGURE 2.11
There are 126 separate bones in the appendicular skeleton (Figure 2.12).
— — — —
FIGURE 2.12
Shoulder girdle Upper extremities Pelvic girdle Lower extremities
•
Hip bone (2)
Basic Radiographic Background of the Vertebral Column
15
Anatomy of a Typical Lumbar Vertebra A typical vertebra consists of the vertebral body and the vertebral ring (Figure 2.13 through Figure 2.17). Each vertebral body is roughly cylindrical in shape and is connected to the vertebral arch by the pedicle on each side. The vertebral arch is composed of two pedicles, two laminae that are fused at the midline and extend a spinous process posteriorly, two superior articular processes, two inferior articular processes, and two transverse processes. In the vertebral column, the superior vertebral notch and the inferior vertebral notch form the intervertebral foramina through which spinal nerves and blood vessels traverse. The inferior articular process and the superior articular process on each side form a joint called a zygapophyseal joint. The zygapophyseal joint is most frequently called a facet. These pictures of the lumbar vertebra are essential to the understanding of the interpretation of fluoroscopic images necessary for appropriate needle placement. Figure 2.13 to 2.17: (1) Vertebral body; (2) pedicle; (3) lamina; (4) spinous process; (5) superior vertebral notch; (6) inferior vertebral notch; (7) superior articular process; (8) inferior articular process; (9) transverse process.
1
1
2
2
4
3
4 7
9
7 1
4
1
2
2 2
1
3
4 9
9
4
FIGURE 2.13 Superior/oblique view of the lumbar vertebrae.
7
5
2 4
8 FIGURE 2.14 Lateral view of the lumbar vertebra.
6
1
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7
9 3 4
6 8
FIGURE 2.15 Oblique view of the lumbar vertebra.
7
3 4 9
8
FIGURE 2.16 Posterior view of the lumbar vertebra.
1 9
FIGURE 2.17 Anterior view of the lumbar vertebra.
Basic Radiographic Background of the Vertebral Column
17
Pelvic Girdle and Sacrum Spinal injections involving the areas of the pelvic girdle and the sacrum include sacroiliac joint injections, caudal epidural steroid injections, sacral transforaminal injections, and so forth. Therefore, we need to be familiar with some anatomic structures of the pelvic girdle and the sacrum (Figure 2.18 through Figure 2.20). 5
5
FIGURE 2.18 Lateral view of pelvis and sacrum; (5), posterior superior iliac spine.
4 5
5
5
1
2
3
2
3
FIGURE 2.19 Posterior view of the pelvis. (1) Posterior sacral foramina, (2) sacral cornu, (3) sacral hiatus, (4) superior articular process, (5) posterior superior iliac spine.
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Classification of Bones and Typical Fluoroscopic Images of Bones Each of the 206 bones of the human body can be classified according to its shape (Figure 2.20 through Figure 2.24): long bone, short bone, flat bone, or irregular bone. It is not difficult to understand a typical fluoroscopic image of a long bone, a short bone, or a flat bone (Figure 2.20 through Figure 2.22).
FIGURE 2.20 Long bone: radius and its fluoroscopic photo.
FIGURE 2.21 Short bone: first phalange and its fluoroscopic photo. A rib shadow
patella
FIGURE 2.22 Flat bones: patella and rib and their fluoroscopic photos.
Basic Radiographic Background of the Vertebral Column
19
However, it is difficult to identify anatomic structures on fluoroscopic images of irregular bones (Figure 2.23).
FIGURE 2.23 Irregular lumbar bone: vertebra and facial bones and their fluoroscopic photos.
It is also easy to visualize a fluoroscopic image of two overlapping bones (Figure 2.24), although this image cannot show the exact relationship between them. And, we cannot judge the spatial relationship between these bones.
FIGURE 2.24 Fluoroscopic photo of a rib on top of the patella.
The outer shell of most bones is composed of hard or dense bone tissue known as compact bone (Figure 2.25). The shaft of a long bone, and possibly of a short bone, is hollow, and it is called the medullary cavity. In the adult, this cavity usually contains fatty yellow marrow.
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Compact Bone
Bone marrow FIGURE 2.25
Each vertebra is an example of an irregular bone. We will consider the fact that each vertebra is built up by several blocks (pieces of flat bones and short bones) (Figure 2.26). The lamina, for example, is a flat block — a flat bone similar to a piece of the rib. Each pedicle, a Latin term meaning “little foot,” is a small block with a cylindrical shape (a piece of short bone) pointing out from the vertebral body posteriorly on each side. Let us illustrate how to “build a typical lumbar vertebra” using building blocks in order to understand the typical fluoroscopic image of a lumbar vertebra.
Spinous process Superior articular process
Lamina Pedicle
Transverse process Inferior articular process Vertebral body FIGURE 2.26
Basic Radiographic Background of the Vertebral Column
21
An x-ray beam penetrates a patient in a prone position. A typical anterior–posterior (A/P) fluoroscopic image of a single lumbar vertebra is shown in Figure 2.27.
Patient in a prone position
A fluoroscopic photo of anterior-posterior view (A/P view) of a single lumbar vertebra
X-Ray tube
FIGURE 2.27
In order to understand how to get an A/P-view fluoroscopic image of a single lumbar vertebra, we must first take apart a lumbar vertebra (Figure 2.28).
X-ray tube
X-ray
FIGURE 2.28
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Figure 2.29 illustrates how to create a two-dimensional A/P fluoroscopic image of the lumbar vertebral body with two pedicles only. The two-dimensional picture of the lumbar vertebral body is a rectangle, and the two-dimensional picture of each pedicle is a circle. 2-D image of vertebral body shadow
2-D image of pedicle shadow
2-D image of vertebral body shadow Pedicles
X-ray tube
FIGURE 2.29
X-ray tube
Basic Radiographic Background of the Vertebral Column
23
A two-dimensional image of the vertebra is like a puzzle. A two-dimensional image of each piece of the vertebra is a single puzzle piece (Figure 2.30). 2-D image of spinous process
2-D image of inferior articular process
2-D image of lamina
2-D image of superior articular process
2-D image of transverse process
2-D image of vertebral body 2-D image of pedicles
X-ray X-ray FIGURE 2.30
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Handbook of C-Arm Fluoroscopy-Guided Spinal Injections
Taking an A/P fluoroscopic image of a single lumbar vertebra is like putting the pieces of the vertebra back together (Figure 2.31). A two-dimensional image of the pedicles and the vertebral arch, including the lamina, the spinous process, the superior and inferior processes, and the transverse processes, brings together a unique puzzle picture (Figure 2.31).
X-ray
FIGURE 2.31
Basic Radiographic Background of the Vertebral Column
25
An A/P fluoroscopic image of a single lumbar vertebra or multiple vertebrae is illustrated in Figure 2.32 and Figure 2.33. The two-dimensional image of pedicles is shown in the fluoroscopic images but not in regular photos of vertebrae. 2 6 5
2
3 4
6 5 3
4
2
2
1
1
1 3 5
4
1
6
6 5
4 3
FIGURE 2.32 (1) Pedicles, (2) superior articular process, (3) spinous process, (4) inferior process, (5) lamina, and (6) transverse process.
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1
2 2 6 3
5
3
4
4
2
2
6
6
5
1
6 3
5
1 5
3
4
4
FIGURE 2.33 (1) Pedicles, (2) superior articular process, (3) spinous process, (4) inferior process, (5) lamina, and (6) transverse process.
Basic Radiographic Background of the Vertebral Column
27
Bibliography Bontrager, K.L. and Anthony, B.T., Eds., Textbook of Radiographic Positioning and Related Anatomy, 2nd ed., C.V. Mosby Company, St. Louis, MO, 1990. Brown, D.L., Ed., Atlas of Regional Anesthesia, 2nd ed., W.B. Saunders, Philadelphia, 1999. Clemente, G.D., Ed., Gray’s Anatomy, 13th ed., Lea & Febiger, Philadelphia, 1984. Fenton, D.S. and Czervionke, L.F., Eds., Image-Guided Spine Intervention, W.B. Saunders, Philadelphia, 2003. Netter, F.H., Ed., Atlas of Human Anatomy, Ciba Geigy Corporation, 1989. Waldman, S.D., Ed., Atlas of Interventional Pain Management, 2nd ed., W.B. Saunders, Philadelphia, 2004.
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Radiation Safety
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As pain medicine becomes increasingly interventional, the use of fluoroscopy has become more prevalent in the performance of spinal and other injections for the diagnosis and relief of chronic pain. Fluoroscopy is even being used, in some instances, in the performance of peripheral injections, e.g., piriformis muscle injections for chronic pain. A basic understanding of radiation safety is an important part of the pain practitioner’s knowledge base, as it facilitates optimal care for our patients. While some of the spinal injection procedures described in this book may also be performed under computed tomography (CT) guidance, all of the procedures described are performed under fluoroscopic guidance; specifically, fluoroscopy using a C-arm. This chapter will briefly review practical safety concepts to minimize the risk of complications from exposure to ionizing radiation. Ionizing radiation can come from x-rays or gamma rays; the radiation being referred to in this chapter is due to x-rays. While gamma rays naturally occur from radioactive atoms, x-rays are those that we deal with in clinical practice — those that are emitted from machines. The principles of fluoroscopy for pain procedures include maximizing patient benefit while minimizing risk to both patient and staff using the ALARA (as low as reasonably achievable) principle. The routine use of fluoroscopy has dramatically increased with the rise in procedures performed by interventional radiologists, cardiologists, and pain physicians. Approximately 500,000 or more procedures for chronic pain are performed annually under fluoroscopic guidance.1 The fluoroscopically guided procedures performed by pain physicians utilize relatively lower amounts of fluoroscopy time in comparison to the other fluoroscopically guided therapeutic procedures, e.g. coronary angioplasty, transjugular intrahepatic portosystemic shunts, and so forth. The vast majority of procedures performed by pain practitioners are generally performed within 1 to 2 min or less of fluoroscopy time, even at teaching facilities. The exposure of physicians to scatter decreases with increased experience.2
Quantification of Radiation Exposure When a human body is exposed to ionizing radiation, there is an interaction with the human atoms that results in energy transfer (absorption). The absorbed dose is the quantity used to evaluate the amount of radiation energy that is deposited into an absorbing medium, for example, human tissue.1 This absorbed dose is described in gray (Gy) units (International System) or the older radian (rad) units (United States). One gray (1 J/kg) is equivalent to 100 rad. Rem (rad equivalent man) is a unit of exposure, vs. Gy, which is a unit of energy. Rem is monitored using the radiation badges worn by hospital personnel. One rem is equivalent to 0.01 sievert (Sv). The annual limits of exposure to health care workers are 5000 mrem to the body; 15,000 mrem to the lens; and 50,000 mrem to the extremities. This does not include the amount of radiation calculated for natural exposure associated with everyday living as well as routine dental examinations. In 1994, the Center for Devices and Radiological Health of the U.S. Food and Drug Administration (FDA) issued an advisory3 cautioning physicians to be aware of the potential for adverse effects to patients who have been exposed to prolonged periods of fluoroscopy. As the skin entry site of the beam is the most susceptible to injury, the advisory stated that skin injury may result after less than 1 h of fluoroscopy, even at typical dose rates. This is far in excess of the fluoroscopic time used for even the most challenging pain procedures. The effects described may not be seen for weeks after radiation exposure. The radiation safety officer of the hospital is a valuable resource for more information on this subject. While performing procedures under fluoroscopy, the goal is to minimize the absorbed dose to the skin and to reduce radiation scatter from the patient to the physician and the staff. Typically, the skin absorbs radiation at a rate of 2 to 5 rad/min. Radiation injury to the skin occurs at the following approximate thresholds4:
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3 Gy (300 rad): temporary epilation (hair removal by the roots) 6 Gy (600 rad): erythema 15 to 20 Gy (1500 to 2000 rad): desquamation, dermal necrosis, and ulceration
Most fluoroscopically guided spinal injections performed by pain physicians are done using a C-arm (Figure 3.1). This provides the benefit of rotating the image to oblique views without having to reposition the patient once the needle is in place. The beam is generated in the x-ray tube, passes through the patient, where it is detected in the image intensifier, and results in a two-dimensional image displayed on the monitor screen. The image intensifier converts the x-ray beams to light energy, producing a clearer image. A lateral view is needed in order to determine the needle depth in addition to the A/P angle view for accurate needle placement. Note that the A/P view is with respect to the patient, not to the procedure table. This is particularly relevant when an A/P view is needed in a patient with scoliosis. This will be discussed in more detail in future chapters.
1
3
2
FIGURE 3.1 Diagram of the C-arm and its components. The arrow pointing from the tube represents the emitting beam of x-rays going through the patient. Note that the image intensifier (above the patient) is as close to the patient as possible. (1) Image intensifier, (2) x-ray tube, (3) prone patient.
Steps to Minimize Radiation Exposure There are steps that pain practitioners can take to minimize radiation exposure to the patient and to the staff: 1. 2.
Use the last image hold to keep the last image seen on the screen and allow the physician to determine the next needle adjustment based on that image. Use the pulsed mode to greatly decrease exposure to the patient. Pulsed mode allows for the emission of short pulses of the beam, resulting in fewer frames per second, which substantially reduces the
Radiation Safety
33
emitted dose when compared to nonpulsed fluoroscopy. In some instances, the radiation exposure may be reduced up to 75%.5 This may take some time to get accustomed to initially, as the image appears somewhat fractionated and is less clear, but the benefits in exposure reduction are substantial. 3. Keep the image within the patient’s body limits. Whenever possible, do not include areas outside of the body habitus when imaging the spine. 4. Use collimation to reduce the size of the x-ray field. This often sharpens the image while reducing scatter. It also helps to keep the main focus of the image in the center of the field; laser markers are also helpful in accomplishing this goal. It is best to keep collimation as tightly around the field of interest as possible to avoid scatter. Remember, scatter from the patient is a major source of exposure to the pain physician. Collimation assists in keeping the image completely within the body habitus of the patient. Note that there are two types of collimation: a. Leaf (linear) collimation (Figure 3.2): This is actually not collimation but a filter. This is helpful in cervical procedures, as it keeps the beam within the patient’s body mass. This is particularly helpful for patients with slender necks. b. Iris (circumferential) collimation (Figure 3.2): This cones down the image to the center of the screen. (See Figure 3.4 for an example of an image taken without collimation.)
FIGURE 3.2 Leaf (linear) collimation.
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FIGURE 3.3 Iris (circumferential) collimation.
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Radiation Safety
FIGURE 3.4 No collimation was used with this image. Note the bright areas where the beam extends outside the patient’s frame.
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36 5.
6.
7.
8.
9.
10. 11.
12.
13.
14.
Whenever possible, intermittent fluoroscopy should be used to minimize exposure time, as radiation dose is directly related to exposure time. Avoid using continuous fluoroscopy, e.g., in obtaining an oblique view of the spine. There is a direct relationship between the amount of radiation exposure (time) and the dose received by the patient and the scatter exposure to the physician.3 This is the aspect of fluoroscopy that is most easily controlled by the physician. As the radiation comes from the x-ray tube, it is best to have the image intensifier as close to the patient as possible. The closer the beam is to the patient, the greater the exposure to the patient. Realize that the exposure decreases with the square of the distance from the beam. Thus, being twice as far away from the source decreases the exposure by a factor of four. The physician should avoid placing any part of his or her body between the x-ray tube (or beam) and the patient. From this principle, it also stands that the farther away from the beam the physician or health care worker is, the lower the exposure. When positioned to perform the block, it is best to be closer to the image intensifier than to the x-ray tube. This becomes difficult with the lateral view in both cervical and lumbar procedures, and special attention should be paid to the position of the physician with regard to the x-ray tube. Realize that the greatest radiation exposure to the physician is due to scatter that is reflected off the patient to the physician. a. Inject contrast via extension tubing and under collimation to keep the physician’s hands out of the beam. If guiding of the needle needs to be done under “live fluoroscopy,” consider placing the needle with the aid of a surgical clamp. b. Recognize the increased risk of exposure to the physician when obtaining lateral views under fluoroscopy,6 especially when injecting dye under lateral fluoroscopy, as the beam is often very close to the physician. This is an issue with lumbar discography, as injections of dye are often performed in the lateral view to visualize dye spread into the nucleus. It is prudent to inject from the side of the image intensifier or to have the technician operate the beam during that time so that the physician may stand at a distance from the beam. Limit the use of magnification. The magnification function permits a magnified view of the image to appear on the screen, which may enhance the ability to accurately view the needle position. However, this comes at the expense of increased radiation exposure. If magnification must be used, limit its use to the lowest magnification setting possible. Placing the patient closer to the beam will magnify the image but at the expense of increased radiation exposure. One method for obtaining a magnified view is to use the “zoom” feature on the machine. This is a feature of the machine that when selected magnifies or “zooms in” to the center of the last image held. It simply magnifies the picture seen on the screen, but it does so without additional radiation exposure. Limit the use of high-level fluoroscopy (HLF) imaging. This function of the fluoroscopy machine increases the current (mA) in order to improve the image quality.8 This function is activated when the “+” sign is pressed on the x-ray switch or foot pedal. Use this function sparingly in order to limit excessive radiation exposure. Avoid continuous fluoroscopy using HLF imaging. HLF is most often used to obtain an image that may then be saved for documentation of the final needle position. Limit personnel in the procedure room to those directly involved with that patient’s care. Most C-arms will automatically adjust to a high voltage (kV) while keeping the current (mA) low. If the setting is placed at “low dose,” then the current decreases by approximately two thirds. This results in a higher voltage per current going through the patient, which is more desirable for both the patient and the pain physician (see Figure 3.5, Figure 3.6A, and Figure 3.6B). With each exposure, there will often be a number expressed in terms of radcm2. This is a calculated measure of radiation emitted by the machine with respect to the patient’s body surface area, known as the dose area product (DAP). While this value has limitations in its interpretation, it is useful as a relative value to try to minimze the DAP exposure for each patient. Obese patients present a challenge, both in needle placement and visualization of the anatomy under fluoroscopy. The use of low-dose settings in these patients results in a reduction in the image clarity; thus, a higher current (mA) is often required to obtain a discernable image. Also, magnification is more often used for these patients in order to get a clearer image. Lastly, the equipment should be well maintained and regularly serviced to ensure good working order (Figure 3.5).
Radiation Safety
37
PULSE
FILM
LOW DOSE
GENERATOR
FIGURE 3.5 Areas on the control panel of the C-arm where pulse and low dose imaging settings may be applied.
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A needle placed in the foramen
(A)
A needle placed in the foramen
(B)
FIGURE 3.6 (A) This image was collimated both longitudinally (vertically) and circumferentially. The image was taken under pulsed fluoroscopy on the “low dose” setting. There is some decrease in resolution, but the needle is still well visualized. (B) The same image without pulsed fluoroscopy. Note the improved resolution.
Radiation Safety
39
Shielding The use of shields may help to decrease exposure to the physician and staff due to scatter from the patient. Below are the most common types of shields in use: 1. Lead aprons decrease exposure to the physicians’ organs by >90%. These aprons should contain a thickness of at least 0.25 mm lead — >0.5 mm thickness provides more protection.6 They should be routinely checked to ensure that they continue to act as effective barriers, and they should not be folded. 2. Thyroid shields protect the thyroid gland from radiation, which may cause thyroid cancer. 3. Protective lead eyewear decreases exposure to the eyes by 90%. Although high doses are required to produce radiation-induced cataracts, the risk also increases with age and the number of years of radiation exposure. The protective eyewear should also be equipped with lateral shields to protect scatter coming from the side. 4. Leaded gloves may be of use. There are some who are opposed to leaded gloves due to the false sense of security that they may confer. The use of leaded gloves, while helpful in reducing scatter to the hands, is not a sustitute for adhering to the above radiation safety principles. If the physician’s hand is left under the beam and he or she is wearing leaded gloves, the fluoroscopy machine, which has automatic brightness control, increases the radiation output in order to get a better image of the practitioner’s hand, thus negating the benefit of the leaded gloves. There is also often a trade-off, as the leaded gloves may decrease the manual dexterity of the physician. 5. Protective mobile barriers are leaded panels that may be placed between the practitioner and the patient.
Radiation exposure is cumulative. Radiation badges should be worn with each exposure and returned for monitoring at monthly or bimonthly intervals. There are different types of monitoring equipment: 1. External exposure: This badge is often worn around the collar. 2. Organ exposure: This badge is worn underneath the lead. 3. Extremity/hand exposure: This is a finger ring — the label should be on the side that is exposed to radiation.
In conclusion, fluoroscopy is a tool that the pain practitioner uses to guide him or her in accurately placing medications around the spinal column, decreasing the volume of injectate necessary to achieve a positive result. Basic knowledge of the risks and possible complications of fluoroscopy is a vital part of performing these procedures.
Bibliography 1. Manchikanti, L., Cash, K., Moss, T.L., and Pampati V., Radiation exposure to the physician in interventional pain management, Pain Physician, 5(4), 385–393, 2002. 2. Manchikanti, L., Cash, K.A., Moss, T.L., Rivera, J., and Pampati, V., Risk of whole body radiation exposure and protective measures in fluoroscopically guided interventional techniques: a prospective evaluation, BMC Anesthesiology, 3, 2, 2003. 3. Brateman, L., The AAPM/RSNA Physics Tutorial for Residents, Imaging & Therapeutic Technology, 19(4). 4. FDA Public Health Advisory, Avoidance of Serious X-Ray Induced Skin Injuries to Patients during Fluoroscopically Guided Procedures, Food and Drug Administration, Rockville, MD, September 9, 1994. 5. Hernandez, R.J. and Goodsitt, M.M., Reduction of radiation dose in pediatric patients using pulsed fluoroscopy, American Journal of Roentgenology, 167, 1247–1253, 1996. 6. Fishman, S.M. et al., Radiation safety in pain medicine, Regional Anesthesia and Pain Medicine, 27(3), 296–305, 2002.
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7. Mahesh, M., Fluoroscopy: patient radiation exposure issues. Radiographic, 21(4), 1033, 2001. 8. OEC Workstation Operator Manual 1998–2001. 9. Archer, B.R. and Wagner, L.K. Protecting patients by training physicians in fluoroscopic radiation management. Am. Coll. Med. Phys., 1(1), 32–37, 2000.
Chapter
Basic Steps for Spinal Injections
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Prior to any spinal injection, there is some basic preparation that needs to take place. All of the necessary supplies and equipment for planned procedures should be available before the case is started. General recommendations will be given for equipment and supplies, and specifics will not be outlined, as different institutions have varying preferences. There are six basic steps for every spinal injection. We will describe all procedures by following these steps: Step 1: Identify the target area or location of the spine that is to be injected, and determine the desired needle pathway. Step 2: Position the patient appropriately for the injection. Step 3: Use fluoroscopy to identify the target area along the patient’s spine. Step 4: Insert the needle into the target point or area of the spine using fluoroscopy as a guide. Step 5: Confirm the needle placement under fluoroscopy. Step 6: Inject the desired medication in the target area.
Step 1: Identify the Target Area or Location of the Spine to Be Injected (Figure 4.1) We often have a spine model in our procedure room for reference. In order to determine the needle path (Figure 4.2), we must determine how to insert the needle from the site to reach the target area or point of the spine.
FIGURE 4.1 Identify the target area or location of the spine.
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Handbook of C-Arm Fluoroscopy-Guided Spinal Injections
FIGURE 4.2 Determine how to insert the needle from the site to reach the target area or point of the spine.
Step 2: Position the Patient for the Injection Figure 4.3 demonstrates that a patient is placed in the prone position.
FIGURE 4.3 Denotes that a patient is placed in the prone position.
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Step 3: Use Fluoroscopy to Identify the Target Area Along the Patient’s Spine This step includes placing the target area of the spine in the center of the TV screen (Figure 4.4 through Figure 4.9), orienting the images of the spine (Figure 4.10), confirming the target level of the spine image (Figure 4.11), and rotating the C-arm to get the desired spinal images for the initial needle insertion (Figure 4.12).
111111 1111 111
111111 111111
FIGURE 4.4 The fluoroscopic photo is displayed in the center of this TV screen.
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Handbook of C-Arm Fluoroscopy-Guided Spinal Injections
111111 1111 111
111111 111111
FIGURE 4.5 The object is displayed on the left side of TV screen. The C-arm should be moved toward the spine.
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111111 1111 111
111111 111111
FIGURE 4.6 The object is displayed on the right side of TV screen. The C-arm should be moved away from the spine.
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1111 1 1
C-arm
1111 111
111111 111111
FIGURE 4.7 The axis of the C-arm should be perpendicular to the axis of a patient’s spine in order to display a perpendicular image on the screen.
11111 1
1111 1 1
1111 111
1111 111
111111 111111
111111 111111
FIGURE 4.8 Images are rotated on screen when the C-arm’s axis is not perpendicular to the axis of patient’s spine.
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Spine film
Spine film
Displaying on TV screen
Patient’s left side
Left
Right
FIGURE 4.9 The C-arm displays an image of the lumbar spine of the prone patient on the TV screen.
T12
L5
Rib Ri
Left
Sacrum
Left
FIGURE 4.10 An image of the sacrum and an image of T12 help confirm levels of the vertebral image.
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Handbook of C-Arm Fluoroscopy-Guided Spinal Injections
L4 FIGURE 4.11 Rotating the C-arm to the patient’s right side to get a right-sided oblique view of the image of the lumbar spine.
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Step 4: Insert and Advance the Needle to the Target Point or Area of the Spine under C-arm Fluoroscopy (Figure 4.12)
A needle
FIGURE 4.12 Demonstration of inserting a needle.
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Step 5: Confirm the Needle Placement In this case (Figure 4.13 through Figure 4.16), we demonstrate a right-sided lumbar transforaminal epidural steroid injection. Contrast solution is injected to outline the target area in the spine to reconfirm the relationship between the needle tip and the target area — the contrast material outlines an epidural space and a spinal nerve root (Figure 4.16 and Figure 4.17).
The initial needle placement FIGURE 4.13
A needle FIGURE 4.14 The depth of the needle placement on a lateral view.
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A needle
FIGURE 4.15 The relationship between the needle tip and the target area of the lumbar spine is rechecked on an anterior–posterior (A/P) view.
Needle
FIGURE 4.16 Lateral view of the lumbar spine.
Contrast material spreads into the epidural space
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Needle
Contrast material spreads into the epidural space and outlines a spinal nerve root
FIGURE 4.17 A/P view of the lumbar spine.
Step 6: Inject the Medication (e.g., local anesthetic and steroid) As the doses of local anesthetic and steroid vary with the individual, we will not be specific in our recommendations.
Bibliography Bontrager, K.L. and Anthony, B.T., Eds., Textbook of Radiographic Positioning and Related Anatomy, 2nd ed., C.V. Mosby Company, St. Louis, MO, 1990. Brown, D.L., Ed., Atlas of Regional Anesthesia, 2nd ed., W.B. Saunders, Philadelphia, 1999. Finton, D.S. and Czervionke, L.F., Eds., Image-Guided Spine Intervention, W.B. Saunders, Philadelphia, 2003. Waldman, S.D., Ed., Atlas of Interventional Pain Management, 2nd ed., W.B. Saunders, Philadelphia, 2004.
Chapter
Fluoroscopic Images of the Lumbar Spine
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Positioning the Patient The prone position is the most frequently utilized position for all lumbar spinal injections (Figure 5.1). A typical fluoroscopic image of the anterior/posterior (A/P) view of the lumbar spine is shown in Figure 5.2.
FIGURE 5.1 Prone position commonly used for lumbar spinal injections.
Anterior/Posterior View of the Lumbar Spine
4 1 6
5
2
3
FIGURE 5.2 Left: A/P view of the lumbar vertebrae. (1) Pedicle, (2) lamina, (3) spinous process, (4) superior articular process, (5) inferior articular process, and (6) transverse process. Right: Photograph of the posterior aspect of a lumbar vertebra.
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Figure 5.3 shows two images of A/P view of patients’ lumbar spines. Often, these images are difficult to interpret.
FIGURE 5.3 A/P views of lumbar spines.
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Obtaining an Oblique View of the Lumbar Spine Figure 5.4 shows a typical fluoroscopic image of the right oblique view of the lumbar spine. The C-arm is rotated to the patient’s right side. The image of the “Scottie dog” helps us to identify the structures of the lumbar vertebrae. The “neck” of the dog represents the connection between the pedicle and the lamina. The “ear” is the superior articular process. The “eye” is formed by the pedicle. And, the ipsilateral transverse process forms the “nose” of the dog.
4
6
1 2
3 5
4 6 1 2 3
5
The “Scottie Dog” image FIGURE 5.4 Image of the right oblique view of the lumbar spine. (1) Pedicle (the eye of the dog), (2) lamina, (3) spinous process, (4) superior articular process (the ear of the dog), (5) inferior articular process (the front leg of the dog), and (6) transverse process (the nose of the dog).
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Figure 5.5 demonstrates how an image of the lumbar spine is changed from an A/P view to an oblique view. The more the C-arm is rotated to the patient’s right, the greater is the distance between the right-sided lateral margin of the vertebral body and the tip of the spinous process. Margin of the vertebral body
Tip of the spinous process
FIGURE 5.5 Change of view of lumbar spine from A/P to oblique.
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Figure 5.6 shows several images of the oblique view of the lumbar spine. The key difference in these images is the relationship between the axis of the superior articular process and the axis of the pedicle shadow. We can get different images of the oblique view (the “Scottie dog” images) of the lumbar spine by rotating the C-arm to the patient’s side with slightly different angles based on the procedures. For example, we may choose Image A for the lumbar medial branch injections. (See the section on lumbar facet injections in Chapter 6 for details.) We may choose Image F for the lumbar discography. (See the section on lumbar discography in Chapter 6 for details.)
FIGURE 5.6 Different images of oblique views of the lumbar spine.
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Obtaining an Lateral View of the Lumbar Spine Figure 5.7 is a typical fluoroscopic image of the lateral view of the lumbar spine. We usually use a lateral view image to confirm needle depth. Figure 5.8 demonstrates that it may be very difficult to determine which image is a true lateral view of the lumbar spine. We obtained these three images by slightly rotating the C-arm without changing needle position (neither advancing the needle nor retracting the needle).
1
4
5
7
2 3
6
FIGURE 5.7 (1) Pedicle, (2) spinous process, (3) superior articular process, (4) inferior articular process, (5) transverse process, (6) vertebral body, and (7) intervertebral foramen.
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FIGURE 5.8 Three-images of lumbar spine (lateral view).
Figure 5.9 illustrates a lateral view of the lumbar spine in a prone position. The shape of the vertebral body is like a cylinder; the transverse processes on the sides, the lamina, and the spinous process form a pie. Two small cylinders (two pedicles) connect “the cylinder” and “the pie.”
Tip of the spinous process Tip of the transverse process Pedicles
Tip of transverse process Vertebral body
FIGURE 5.9 Lateral view of lumbar spine in prone position.
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We can easily view a clear lateral vertebral body (the cylinder) with pedicles by having the x-ray beam pass through a diameter of the cylinder (Figure 5.10A). However, it may be difficult to determine a true lateral view of the vertebral body, because the cylinder has many diameters (Figure 5.10B). Therefore, it is not easy to determine needle depth by using images of the lateral view only (Figure 5.11).
A
FIGURE 5.10
B
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Figure 5.11 illustrates different images of the lateral view of the lumbar spine without moving needles. Rotating the C-arm at slightly different angles can change the distances between the tip of the needle and the anterior margin of the vertebral body.
A
B
FIGURE 5.11 Lateral views of the lumbar spine.
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Other structures in the lateral view of the lumbar spine, including the transverse process, the superior articular process, the interior process, and the spinous process, do not provide additional information for determining a true lateral view of the lumbar spine (Figure 5.12A). A twodimensional image of the lumbar spine can be illustrated as in Figure 5.12B. We are able to easily identify the vertebral body, the pedicle, and the intervertebral foramen. Vertebral body
Vertebral body
Intervertebral foramen Intervertebral foramen
Pedicle
Pedicle A FIGURE 5.12
B
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Suggestions on How to Check the Needle Depth When imaging the lumbar spine, it is difficult to check the needle depth by realigning the images of the lateral view alone (Figure 5.11). In contrast, it is easy to get a true A/P view of the lumbar spine if an x-ray beam goes through the diameter of “the cylinder” and is perpendicular to “the pie” (Figure 5.13). Therefore, we recommend using images of both the lateral view and the A/P view of the lumbar spine together to confirm needle depth (Figure 5.14). The perpendicular Tip of the spinous process
Tip of the transverse Pedicles
Tip of transverse process Vertebral body
The diameter
A
B
FIGURE 5.13 Fluoroscopic images of A/P views of the lumbar spine. The spinous process (A) is located at the midline of the vertebral body, and the vertebral body (B) is squared (commonly used terminology).
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FIGURE 5.14 Images of the lateral view and the A/P view should also be used to check the needle depth. (A) Lateral view. The tip of this needle is located slightly posterior to the anterior margin of the vertebral body. (B) A/P view. The tip of the needle is located in the center of the pedicle shadow.
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Bibliography Bontrager, K.L. and Anthony, B.T., Eds., Textbook of Radiographic Positioning and Related Anatomy, 2nd ed., C.V. Mosby Company, St. Louis, MO, 1990. Brown, D.L., Ed., Atlas of Regional Anesthesia, 2nd ed., W.B. Saunders, Philadelphia, 1999. Clemente, G.D., Ed., Gray’s Anatomy, 13th ed., Lea & Febiger, Philadelphia, 1984. Fenton, D.S. and Czervionke, L.F., Eds., Image-Guided Spine Intervention, W.B. Saunders, Philadelphia, 2003. Netter, F.H., Ed., Atlas of Human Anatomy, Ciba Geigy Corporation, Tarrytown, 1989. Waldman, S.D., Atlas of Interventional Pain Management, 2nd ed., W.B. Saunders, Philadelphia, 2004.
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Chapter
Lumbar Spinal Injections
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Lumbar Spinal Injections This chapter addresses injections in and around the lumbar spine. We start off with the simplest to perform, the lumbar medial branch block, and advance to the more technically challenging lumbar discogram. The pain physician should be skilled in the performance of lumbar spinal injections prior to attempting to perform injections within the thoracic or cervical regions. Patient preparation: We ask the patients not to ingest any solid foods for a minimum of 6 hours prior to the procedure. We recommend that the patients have another individual available to transport them home following the procedure. Heart rate, blood pressure, and oxygen saturation may be monitored. Pregnancy is a contraindication to the performance of all spinal injections under fluoroscopy. Equipment/Materials: • • •
• • • •
A 22- or 25-gauge 3½ in. spinal needle with or without a distal curved tip in the direction of the bevel. Water-soluble nonionic contrast. Local anesthetic (e.g., 0.25 to 0.5% bupivacaine or 2% lidocaine) and steroid. The volume of injected material will vary depending on the injection performed. Diagnostic injections are performed with a low volume (<1 ml), while therapeutic injections may be performed with a slightly larger volume. Note that the local anesthetic and the steroid may be injected together as a solution or separately. Steroids are not necessary for medial branch injections. A syringe (or syringes) for injecting the local anesthetic and steroid. A 3 ml or 5 ml syringe is recommended. Connection tubing to allow for dye injection without radiation exposure to the hands. This also facilitates an immobile needle. Lidocaine (0.5 to 2%) and a thin (25- to 27-gauge) needle for local infiltration. When using 25-gauge spinal needles in the lumbar region and the patient’s anatomy is easily visualized, local anesthetic skin infiltration is often not necessary.
Sedation: Light sedation is recommended, e.g., with midazolam 1 to 2 mg intravenously.
Lumbar Medial Branch Block The lumbar medial branch block is one of the most commonly performed spinal injections in our practice; it is also among the easiest to perform. We thus recommend using this block to teach beginner pain physicians the technique of basic spinal injections. Lumbar medial branch injections are often performed as diagnostic injections for pain arising from the lumbar facets.1,2 Their use as therapeutic injections was also reported.1 Indications: Axial low back pain that does not radiate distal to the knee Low back pain without radicular symptoms Mechanical low back pain Contraindications: Patient refusal Systemic anticoagulation or coagulopathy Systemic or localized infection at the site
Step 1: Identify the Target Area on the Lumbar Spine The target area is the area or small groove where the superior articular process joins the base of the transverse process of the lumbar vertebra. The lumbar medial branch lies against the bone in this region (Figure 6.1).
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A
The target area
B
Medial branches
FIGURE 6.1 (A) Photograph of a right-sided oblique view of the lumbar vertebrae. The dot indicates the target area of the lumbar vertebra for a medial branch injection. (B) Location of lumbar medial branches.
The lumbar medial branch is the medial branch of the dorsal primary ramus of the spinal nerve root (Figure 6.2). The needle is advanced toward the target area posteriolaterally (Figure 6.3).
Lumbar medial branch
Lumbar Spinal nerve root
Dorsal primary ramus
FIGURE 6.2 Origin of the lumbar medial branch in a right-sided oblique view of the lumbar vertebrae.
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A B
FIGURE 6.3 (A) Needle placements in a posterior view. (B) Needle placements in an oblique view.
Step 2: Position the Patient The patient is in a prone position, and the C-arm comes in from the patient’s side (Figure 6.4).
FIGURE 6.4 Patient in prone position; C-arm at patient’s side.
Step 3: Use the Fluoroscopy to Identify the Target Area To get a true lumbar A/P image (Figure 6.5), we must identify the target levels and orient the images.The C-arm is rotated and tilted to get an anterior–posterior (A/P) image of the target lumbar vertebra. The L1 spinal nerve root, for example, exits from the spine via the intervertebral foramen between L1 and L2. The L1 posterior ramus and its medial branch lie against the bone at the junction between the superior articular process and the transverse process of L2 (not L1). This means that the L1 medial branch is injected at the level of the L2 transverse process; the L2 medial branch is located at the level of the L3 transverse process; the L3 medial branch is located at the level of the L4 transverse process; the L4 medial branch is located at the level of the L5 transverse
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process; the L5 dorsal ramus is located just lateral to the S1 superior articular process (Figure 6.6). In order to count levels of lumbar medial branches, we must understand how to number the spinal nerve roots, because lumbar medial branches are the terminal branches of the spinal nerve roots. Each spinal nerve root comes from the vertebral column via an intervertebral foramen.
Right Rib
L2 Tip of a metal pointer
FIGURE 6.5
T12
B
A
T12
T12 MB L1 L1 L1 MB L2 L2 L2 MB L3
L3 L3 MB
L4
L4 L4 MB L5
L5 L5 Dorsal Ramus
Sacrum
FIGURE 6.6
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Step 4: Insert the Needle into the Target Area It is important to understand how to choose fluoroscopic images of the target lumbar vertebra for the initial needle insertion.
The A/P View The location of a lumbar medial branch is demonstrated in Figure 6.7. The target point is located medially and inferiorly to the junction point between the lateral margin of the superior articular process and the superior margin of the transverse process. A
B
Junction point between lateral margin of the superior articular process and the superior margin of the transverse process
Medial branch
C
FIGURE 6.7 (A) A/P viewed lumbar vertebrae (B) Location of the medial branch (the white dot line outlines the lateral margin of the superior articular process and the superior margin of the transverse process). (C) White dots are possible target points for the medial branch injection.
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Correct needle insertion in the A/P view may be difficult to determine, because it is very difficult to outline the entire lateral margin of the superior articular process (Figure 6.7), and the distal portion of the lumbar medial branch varies. We recommend using the lateral view to recheck needle placement (Figure 6.8). Superior articular process Needle
B
A
Medial br anch
Superior articular process Needle D
C
FIGURE 6.8 (A) Laterally viewed photograph of a lumbar vertebra with correct needle placement for the medial branch block. (B) Laterally viewed fluoroscopic image of the lumbar vertebra with correct needle placement. (C) Laterally viewed photograph with a needle tip contacting the posterior margin of the superior articular process. (D) Laterally viewed fluoroscopic image with a needle contacting the posterior margin of the superior articular process.
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We recommend using an obliquely viewed fluoroscopic image of the lumbar vertebra to guide needle placement for the lumbar medial branch injection (Figure 6.9).
A target point
A
Medial branch
B
An ideal target point for the lumbar medial branch
C FIGURE 6.9 (A) Right-sided obliquely viewed photograph of a lumbar vertebra. (B) Right-sided obliquely viewed fluoroscopic image of a lumbar vertebra. (C) Target point for needle insertion.
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The reasons for using the oblique image for the lumbar medial branch injection include that we can block the proximal portion of the medial branch (Figure 6.10A through Figure 6.10D), and it is easy to identify the lateral margin of the superior articular process (Figure 6.10D).
B
A
Distal portion of the medial branch
C
D
Proximal portion of the medial branch
Distal portion of the medial branch FIGURE 6.10 The obliquely viewed fluoroscopic image is better for guiding the lumbar medial branch injection.
Using a variety of oblique images of the lumbar vertebra may not significantly affect needle placement for the lumbar medial branch. However, the needle tip must contact the area below the junction between the lateral margin of the superior articular process and the superior margin of the transverse process (Figure 6.11).
A
B
C
FIGURE 6.11 Series of right-sided obliquely viewed photographs of a lumbar vertebra. A through C demonstrate that the more the vertebra is rotated, the better the proximal portion of the medial branch can be visualized.
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We suggest rotating the C-arm only enough to clearly identify the lateral margin of the superior articular process (Figure 6.12). The lateral margin of the pedicle shadow usually overlies the junction between this lateral margin and the superior margin of the transverse process. On the other hand, the target point is at about the one o’clock or two o’clock position on the pedicle shadow (Figure 6.12B).
A
B
Target point FIGURE 6.12 (A) Right-sided obliquely viewed lumbar vertebra. (B) Target point for the needle placement of the lumbar medial branch injection. The white dotted line outlines the lateral margin of the superior articular process shadow and the superior margin of the transverse process.
After choosing the ideal fluoroscopic image, a needle is inserted and advanced under fluoroscopic guidance until the needle tip contacts the target point.
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Special Considerations for the L5 Dorsal Ramus Injection The L5 “medial branch” is not the medial branch of L5 but rather the dorsal primary ramus of the L5 (Figure 6.13) spinal nerve. The L5 dorsal primary ramus lies against the bony groove formed by the sacral ala and the superior articular process of S1.
A
B
L5 dorsal ramus
Right-sided L5 dorsal ramus
L5
Right-sided L5 dorsal ramus Sacral ala Posterior of the sacrum
Anterior surface of the sacrum C
FIGURE 6.13 (A) Photograph of the posterior view of the lower portion of the lumbar spine. (B) Right oblique view of the lower portion of the lumbar spine. (C) Right-sided lateral-superior view of the L5 and the sacrum.
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The needle insertion for the L5 dorsal ramus injection includes a posterior approach and an oblique approach: 1.
The posterior approach is achieved using an A/P-viewed fluoroscopic image of L5 as a guided image for the initial needle placement. The target zone is the area that is slightly inferior to the junction point between the base of the superior articular process of S1 and the sacral ala (Figure 6.14).
Sacral ala
S1 superior articular process
L5
B
L5 medial branch
Right-sided L5 medial branch target point (white dot)
A
FIGURE 6.14 (A) Fluoroscopic image of an A/P view of the L5 and the top portion of the sacrum. The white dot shows the target point of the right-sided L5 medial branch injection. (B) Photograph of the posteriorly viewed area between L5 and the sacral ala that illustrates the location of the right-sided L5 medial branch.
2.
An oblique approach is employed using an obliquely viewed fluoroscopic image as a guided image for the initial needle placement. The C-arm is slightly rotated to the affected side about 10 to 20˚ (Figure 6.15).
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A
B
The target point for the right-sided L5 dorsal ramus injection
Right-sided L5 dorsal ramus
The target point for L5 dorsal ramus
FIGURE 6.15 (A) Right-sided obliquely viewed L5 image. (B) Photograph of the right-sided obliquely viewed area between L5 and the sacral ala.
We emphasize the importance of identifying the S1 articular process and the sacral ala for the L5 dorsal ramus block regardless of the approach.
Step 5: Confirm the Needle Placement The needle placement for the lumbar medial branch block at all levels can be rechecked in a lateral view of the lumbar spine (Figure 6.16). Superior articular process
B
A
The needle tip is located below the lower margin of the intervertebral foramen and advanced not beyond the posterior margin of the intervertebral foramen.
FIGURE 6.16 Correct needle placement for the lumbar medial branch block in the lateral view. (A) Photograph of the lateral view of the lumbar spine with a placed needle of the lumbar medial branch block. (B) Fluoroscopic image of the lumbar spine with a placed needle
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We may also need to use an A/P view and a lateral view of L5 together to recheck the needle placement for an L5 medial branch block. If we put the C-arm back to the neutral position (Figure 6.17), the needle tip will aim significantly caudally in the A/P view (Figure 6.18).
A
B
FIGURE 6.17 (A) The C-arm is in a neutral position. (B) The x-ray beam does not align with the L5/S1 disc.
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A B
C
D
FIGURE 6.18 Needle placement for the right-sided L5 dorsal ramus block in the A/P view. (A) Posteriorly viewed photography with a placed needle for the right-sided L5 dorsal ramus block. (B) A/P image of the right-sided L5 dorsal ramus block. (C, D) The needle directions may look different if the angles of the view are different.
Rechecking the needle placement in the lateral view should follow the same criteria as described previously — the needle tip should be located below the lower margin and behind the posterior margin of the L5/S1 intervertebral foramen (Figure 6.19).
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A
The iliac crest shadow
L5/S1 intervertebral foramen B1
B2 The needle tip is located below the lower margin of the intervertebral foramen and posterior to the posterior margin of the intervertebral foramen.
FIGURE 6.19 Illustration of how to recheck the needle placement for the L5 dorsal ramus block in the lateral view. (A) Photograph of the lateral view of the lower portion of the lumbar spine and the iliac crest. The iliac crest covers the needle tip. (B1) Laterally viewed fluoroscopic image of the needle placement for the L5 dorsal ramus block. (B2) The same image as B1 with labels.
Step 6: Inject the Medication Lumbar Medial Branch Denervation Indications: If the patient receives temporary but significant (>70%) pain relief from diagnostic lumbar medial branch injections, he or she is a good candidate for the lumbar medial branch denervation. We follow the same step to get a slightly obliquely viewed image of the target vertebra (Figure 6.20). We usually choose the initial radiofrequency needle entry point at the lower margin of the transverse process and slightly lateral to the lateral margin of the pedicle shadow (Figure 6.21A). The needle is then advanced slightly medially and cephalically. The end point of the process is when the needle tip contacts the junction point between the superior articular process and the transverse process, as we described in the above section on the lumbar medial branch block (Figure 6.21B).
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A
B
FIGURE 6.20 (A) Right-sided oblique view of the lumbar vertebra above L5. (B) Right-sided oblique view of the L5 vertebra.
The initial needle entry point (A)
(B)
FIGURE 6.21 (A) Initial entry point and (B) target area.
Needle placement should be rechecked at the lateral view, as described in the lumbar medial branch block section, above.
Lumbar Transforaminal Epidural Steroid Injection Step 1: Identify the Target Area Needle entry is via an intervertebral foramen posteriolaterally (Figure 6.22A and Figure 6.22B).
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B
FIGURE 6.22 (A) Photograph of a posterior view of the lumbar spine with a needle approaching the foramen. (B) Photograph of the lumbar spine with a needle approaching in the oblique view.
Step 2: Position the Patient The patient is in a prone position, and the C-arm comes in from the patient’s side (Figure 6.23).
FIGURE 6.23 C-arm at side of patient in prone position.
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Step 3: Use Fluoroscopy to Identify the Target Area The C-arm is rotated and tilted to get an A/P image of the target lumbar vertebra (Figure 6.24A through Figure 6.24C). The C-arm is then rotated toward the affected side to get an oblique fluoroscopic image of the target lumbar vertebra (Figure 6.25A and Figure 6.25B). T12 L5 Left
Right Rib
A shadow of a metal pointer
Sacrum
A
B
A shadow of a metal pointer
C
FIGURE 6.24 (A, B) Orientation of the image; the levels may be counted from T12 to ensure that there are five lumbar vertebrae. (C) A/P view of the first to third lumbar vertebrae. Their spinous processes are at the midline of the vertebral bodies, but only the L1 and L2 vertebral bodies are squared.
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A
B
FIGURE 6.25 (A) Photograph of the lumbar spine, right oblique view. (B) Fluoroscopic image of the lumbar spine, right oblique view.
In general, the best oblique view of the lumbar spine for a lumbar transforaminal epidural steroid injection is obtained when the superior articular process at the target level intersects the center of pedicle shadow that is located immediately above (Figure 6.26).
Tip of superior articular process points up to the center of the pedicle above. Target vertebra
FIGURE 6.26 Correct right oblique view of lumbar vertebrae for lumbar transforaminal epidural steroid injection.
Step 4: Insert the Needle to the Target Area When performing a lumbar transforaminal injection, the entry (Figure 6.27A) is located as follows: At the inferior margin of the transverse process at the target vertebra Superior to the tip of the superior articular process at the level below the target vertebra Lateral to the lateral margin of the inferior articular process at the level below the target vertebra
Figure 6.27B shows the initial needle placement.
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Target vertebra
Inferior margin of transverse process Lateral margin of inferior articular process Tip of superior articular process
A
Needle
B
FIGURE 6.27 (A) Zone of initial needle placement. (B) Fluoroscopic image of the initial needle placement for right-sided lumbar transforaminal epidural steroid injection.
Step 5: Confirm the Needle Placement The depth of the needle should be checked with lateral views. The final depth of the needle in the lateral view is located between the middle and the posterior one third of the intervertebral foramen (Figure 6.28A). In the A/P view, the needle tip should be located underneath the pedicle shadow, with the area between the medial margin and the center of the pedicle shadow at the target level (Figure 6.28B). If the patient experiences severe paresthesias, regardless of the needle position, the needle must be repositioned.
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B
A The needle tip is located at the midway and upper one third of intervertebral foramen
The needle tip is located underneath of the pedicle and between the medial margin and center of the pedicle
FIGURE 6.28
A lateral image and an A/P fluoroscopic image of epidurogram, which may include a nervegram, should be obtained. Vertical epidural spread of the contrast agent is visualized within the posterior aspect of the intervertebral foramen in the lateral view (Figure 6.29A). In the A/P view, the contrast agent spreads underneath and medial to the pedicle shadow and outlines the target spinal nerve exiting the foramen (Figure 6.29B).
(A) FIGURE 6.29
(B)
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Step 6: Inject the Medication We recommend injecting 1 to 2 ml of 0.25% of bupivacaine and 10 to 40 mg (0.2 to 1 ml) of steroid.
Special Considerations of Oblique Views It is important not to under- or overrotate the C-arm in obtaining an ideal fluoroscopic image (Figure 6.30). Learning how to get the correct oblique image of the lumbar spine is important for performing lumbar transforaminal epidural steroid injections. The following figures demonstrate oblique images of the lumbar vertebra that can interfere with accurate needle placement (Figure 6.30A through Figure 6.30C).
A
B
C
FIGURE 6.30 (A) C-arm in a neutral position. (B, C) The C-arm when it is rotated to the patient’s right side at varying angles.
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Rules for Getting Oblique Views of the Lumbar Spine Figure 6.31 demonstrates that the needle cannot be inserted into the intervertebral foramen if it is inserted perpendicularly to the vertebral body, posterior–anterior from above the tip of the superior articular process. For this reason, we do not use the A/P view of the lumbar spine to guide the initial needle insertion.
A B
C
Vertebral body Transverse process
Needle
Spinal nerve root
Pedicle Spinal cord
Tip of superior articular
Spinous process lamina
FIGURE 6.31 (A) Photograph of the lumbar spine with a needle in the posterior view (B) A/P fluoroscopic image of the lumbar spine. (C) Diagram showing the difficulty encountered when the needle is inserted from the skin perpendicularly to the vertebral body from above the tip of the superior articular process.
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Figure 6.32 shows the difficulty in accurately placing the needle into the intervertebral foramen when there is underrotation of the image of the lumbar vertebra by C-arm.
Tip of superior articular process points up to the lateral margin of the pedicle at the level above
A
B
C
FIGURE 6.32 (A) Photograph of under-rotated lumbar vertebrae with a needle entry from right oblique view. (B) Fluoroscopic image of the lumbar spine showing the right oblique view, under-rotated. The tip of the superior articular process points up to the lateral margin of the pedicle shadow above. (C) Example of how an under-rotated vertebra makes the needle placement more difficult.
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Proper rotation of the C-arm with respect to the lumbar vertebrae allows the needle tip to pass easily into the intervertebral foramen (Figure 6.33).
Tip of superior articular process points up to the center of the pedicle at the level above
A
B
C
Needle
FIGURE 6.33 (A) Photo of properly rotated vertebrae to the right. (B) Fluoroscopic image of the lumbar spine, right proper oblique view. The tip of the superior articular process points up to the center of the pedicle shadow at the level above. (C) Proper rotation of the lumbar vertebra and the proper needle placement. The needle is able to be inserted into the intervertebral foramen.
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Figure 6.34 demonstrates that overrotation of the C-arm also increases the difficulty of performing accurate needle placement.
The tip of superior articular process is located at the center of the disc space
A
B
C
Needle FIGURE 6.34 (A) Lumbar vertebrae over-rotated to the right. (B) Fluoroscopic image of lumbar vertebrae over-rotated to the right because the tip of the superior articular process is at the midway of the disc space between two vertebrae. (C) Improper needle placement.
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The following images (Figure 6.35) illustrate a left transforaminal epidural steroid injection at the level of L4/L5. We changed C-arm rotations to correct the initial inaccurate needle positions. C
B
A
D
E
Tip of superior articular process points up to the lateral margin of pedicle at level above
Tip of superior articular process points up to the center of pedicle at the level above
F
G
H
I
FIGURE 6.35 (A) Initial needle insertion in the left oblique view. (B) A false “proper needle location” at the lateral view (needle tip at the upper one third and at the midway of the intervertebral foramen). (C) Needle tip away from the spine in the A/P view. (D) A second oblique view obtained by rotating the C-arm to the left. The initial needle entry in (A) was medial to the superior articular process. (E–H) In order to obtain the proper needle placement it was necessary to check the oblique, lateral, and A/P views. (I) A correct segmental epidurogram with a nervegram.
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The images shown in Figure 6.36A through Figure 6.36H demonstrate how overrotating the C-arm also results in improper needle placement. Figure 6.36A shows the superior articular process of L2 pointing up to the medial margin of the pedicle shadow at the level above. Figure 6.36B through Figure 6.36D show the needle placement when this overrotated oblique view is used. Figure 6.36E and Figure 6.36F show “proper” needle placement in the A/P view and in the lateral view. However, Figure 6.36F shows improper spread of contrast agent. Figure 6.36H confirmed that it is not an epidurogram.
A
B
C
D
E F
H
G
Improper spread of contrast agent
This contrast image is not an epidurogram
FIGURE 6.36 Improper spread of contrast agent.
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Sometimes getting an ideal oblique image of the lumbar vertebrae for lumbar epidural steroid injections is difficult, because the shapes of patients’ lumbar vertebrae vary. This means that we cannot always use the relationship between the tip of the superior articular process and the pedicle shadow at the level above on the oblique view (Figure 6.37A through Figure 6.37D) to decide a proper C-arm oblique rotation.
Target vertebra
Tip of superior articular process points up to the center of the pedicule above
FIGURE 6.37
In Figure 6.38A through Figure 6.38D, the relationship between the tip of a superior articular process could not be used as a guide for the lumbar transforaminal epidural steroid injection. Figure 6.38A looks like an overrotated oblique view lumbar spine image, because the tips of the superior articular processes at each level from L2 to L4 point up to the medial margin of the pedicle shadow above. In Figure 6.38B, the needle is inserted between L1 and L2. Figure 6.38C shows an A/P view of proper needle placement, as the needle tip is located below the pedicle shadow and also medial to the medial margin of the pedicle shadow. Figure 6.38D shows a correct epidurogram and nervegram.
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A
Needle
C
FIGURE 6.38
B
Needle
D
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We believe that the angle between the transverse process and the superior process (Figure 6.39) is one of the factors that accounts for varying appearances of the lumbar vertebrae in the oblique view. Angle between transverse process and superior articular process
FIGURE 6.39 The arrow shows the angle between the transverse process and the superior articular process.
We can use the relationship between the tip of the superior articular process and the upper margin of the vertebral body as a guide to confirm the correct oblique view if the angle is close to 90° (Figure 6.40). This does not hold true if this angle is much bigger than 90˚ (Figure 6.41). An almost 90° angle
FIGURE 6.40 The angle in this example is sharp.
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Angle much bigger than 90 degrees
FIGURE 6.41 The angle pictured here is greater than 90°.
This angle is less than 90 degrees.
FIGURE 6.42 We have not observed an angle between the transverse process and the superior articular process that is less than 90°.
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Therefore, we recommend using at least two rules together to check for optimal oblique images for lumbar epidural steroid injections: Rule 1: The tip of the superior articular process bisects the center of the pedicle shadow at the level above (Figure 6.43 A). Rule 2: The tip of the superior articular process is located at one third of the disc space (Figure 6.43B).
Tip of superior articular process bisects the pedicle shadow above
(a)
1/3 1/3
1/3
(b) FIGURE 6.43
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We consider Rule 2 to be more important than Rule 1 to determine a proper C-arm position for obtaining a correct oblique image of lumbar spine. We also recommend always using both lateral and A/P images to guide and check needle depth and direction. Figure 6.44A, an oblique view, shows that a needle is inserted below the transverse process (below the pedicle in the fluoroscopic image), lateral to the inferior articular process, and above the superior articular process. Image B, a lateral view, shows that the needle tip is located in the upper one third of the intervertebral foramen. Image C, an A/P view, shows that the needle tip is underneath the pedicle. Figure 6.44 illustrates proper needle placement in oblique, lateral, and A/P views. If we use only a lateral image to check the needle depth, we may not be able to identify improper needle placement. Figure 6.45 demonstrates that three needle placements can give similar lateral photographs.
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A
B
C
FIGURE 6.44 Proper needle placements in oblique view (A), lateral view (B), and A/P view (C).
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FIGURE 6.45 The above pictures show that three different needle entrance sites in the A/P views can result in the same needle position in the lateral view.
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Figure 6.46 illustrates that needles are inserted in different directions to the lumbar spine, proven by A/P views (images A and B). However, lateral images (images C and D) show that these two needle depths are similar.
A
B
C
D
FIGURE 6.46 A/P views of needles inserted from different directions (A and B). Lateral images showing similar needle depths (C and D).
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The following two cases show how to confirm needle placements: Case 1 (Figure 6.47): Correct needle placement at a level between L4 and L5 on the right side.
Use Rule #1 and #2 to choose an oblique for the initial needle
Use lateral view and A/P view to confirm the needle depth and needle driving direction
Lateral epidurogram FIGURE 6.47 Proper needle placement between L4 and L5 on right side.
A/P epidurogram
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Case 2 (Figure 6.48): Another correct needle placement at a level between L4 and L5 on the right side.
Use Rule # 1 and #2 to choose an oblique for the initial needle
Use lateral view and A/P view to confirm the needle depth and needle driving direction
Lateral epidurogram
A/P epidurogram
FIGURE 6.48 Another proper needle placement between L4 and L5 on right side.
Lumbar Transforaminal Epidural Steroid Injection at the Level of L5/S1 Step 1: Identify the Target Area The needle is inserted into the intervertebral foramen between L5 and the first sacral segment (ala or wing of the sacrum) (Figure 6.49).
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Ala or sacral wing FIGURE 6.49 Insertion of needle into intervertebral foramen between L5 and first sacral segment.
Step 2: Position the Patient The patient is in the prone position, as they would be for any other lumbar procedure (Figure 6.50).
FIGURE 6.50 Patient in prone position.
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Step 3: Use C-Arm to Identify the Target Area Obtaining appropriate fluoroscopic images for L5/S1 transforaminal epidural steroid injections is different than obtaining those for the upper lumbar levels, although the same principles and rules described above apply. There are several special considerations at this level. These include the lumbar lordosis (Figure 6.51A and Figure 6.51B), the sacral promontory (Figure 6.51C), and the concave shape of the sacrum (Figure 6.51B). The vertebral column forms a series of anteroposterior curves. A lordosis is defined as any convex forward curve. The curvature of an adult’s lumbar spine (Figure 6.51) is a convex forward curve.
A Lumbar lordosis (convex forward curve) Sacral curvature (concave forward)
B
C Lumbar lordosis
FIGURE 6.51 Curvature of adult lumbar spine.
Sacral promontory
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In order to square the L5 vertebral body or to open the disc space between L5 and S1 in the A/P view, the C-arm needs to have a significant cephalic tilt (Figure 6.52). This tilt varies among patients based on their degrees of lumbar lordosis, the severity of the sacral promontory, and the degrees of sacral curvature (Figure 6.53).
FIGURE 6.52
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FIGURE 6.53
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If the fluoroscopic beam does not align with the disc between L5 and S1 (Figure 6.54A), the tip of the spinous process of L5 will be located above or on the posterior lower margin of the L5 vertebral body (Figure 6.55B and Figure 6.55C). When the C-arm is tilted in a cephalic direction, it allows the fluoroscopic beam to align with the L5/S1 disc (Figure 6.55A). The tip of the spinous process of L5 will be located below the posterior inferior margin of the L5 vertebral body (Figure 6.55B and Figure 6.55C). The C-arm is then rotated to the affected side (Figure 6.56) to get an obliqueviewed L5 (Figure 6.57A). We still follow Rule 1 as we described above to have the tip of the S1 superior articular process bisecting the pedicle shadow of L5 (Figure 6.57B).
A
X-tube
Lower margin of L5 lamina
Tip of spinous process is located above the posterior lower margin of L5 vertebral body
B
c Posterior margin of sacrum body
Posterior lower margin of L5 vertebral body FIGURE 6.54 In (B) and (C) the fluoroscopic beam is not aligned with the disc between L5 and S1. (B) Posterior view of L5 and the disc space between L5 and S1 when the fluoroscopic beam is not aligned with the disc. (C) A/P image of an L5 body whose image is not squared.
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A The tip of the spinous process is located below the posterior inferior margin of the L5 vertebral body. X tube
B
The posterior lower margin of the L5 vertebral body
C
FIGURE 6.55 The fluoroscopic beam is aligned with the L5/S1 disc. (B) The appearance of the L5 vertebral body and the disc space between L5 and S1 when the fluoroscopic beam aligns with the disc. (C) A/P viewed image of a squared L5 body.
FIGURE 6.56
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Tip of S1 superior articular process bisects L5
A
B
FIGURE 6.57 (A) Photograph of L5, left oblique view. (B) Fluoroscopic image of L5, left oblique view; the tip of the left superior articular process bisects the pedicle shadow at L5.
A triangular-shaped needle entry zone is formed by the iliac crest (lateral), the lateral margin of the S1 superior articular process (medial), and the inferior margin of the transverse process (superior) (Figure 6.58). The needle should be inserted above the tip of the S1 superior articular process (Figure 6.59). L5 transverse process
S1 superior articular process
Iliac crest FIGURE 6.58
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FIGURE 6.59
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However, we observed that the needle entry zone as described above varies among patients due to the differences in the appearance of the iliac crest (Figure 6.60). These differences sometimes make needle insertion very difficult, because a high iliac crest line may cover the needle entry zone in the oblique view (Figure 6.61).
L5
L5 B
A
L5
CC
FIGURE 6.60 Different appearances of the iliac crest. A is higher than B. C is lower than A and B.
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L5
L5 Iliac crest line A Iliac crest
L5
L5 Iliac crest line Iliac crest
B
L5 L5
Iliac crest line C Iliac crest FIGURE 6.61 Different appearances of the iliac crest in a left oblique view.
We recommend always trying to rotate the C-arm to the affected side until the superior articular process of S1 bisects the L4 pedicle shadow in order to get an initial needle entry point if the iliac crest line is low in this view (Figure 6.62).
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Needle FIGURE 6.62 Initial needle placement for left-side L5/S1 transforaminal epidural steroid injection.
Step 4: Insert the Needle to the Target Area However, if the iliac crest covers the needle entry zone in an oblique view, we recommend rotating the C-arm until this needle entry zone is maximally open. The needle entry will then be chosen at a position lateral to the tip of the S1 superior articular process (Figure 6.63). The needle is then advanced in this oblique view until it contacts either the upper portion of the lateral margin of the S1 superior articular process or the inferior portion of the lateral margin of the L5 inferior articular process (Figure 6.64).
Initial needle entry point
A
L Iliac crest line
B
FIGURE 6.63 (A) Marked needle entry point in an oblique view. (B) Initial needle placement.
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B The needle tip contacts the lateral side of the S1 superior articular process
FIGURE 6.64 (A) The needle contacts the lateral margin of the S1 superior articular process. (B) The needle tip contacts the upper portion of the lateral margin of the S1 superior articular process.
The needle tip behind S1 superior articular process FIGURE 6.65 The needle tip is behind the S1 superior articular process.
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Step 5: Confirm the Needle Placement The depth of the needle placement should be checked in a lateral view (Figure 6.66A) and an A/P view as described before (Figure 6.66B).
A
B
FIGURE 6.66 Lateral view of needle placement (A). A/P view of needle placement (B).
A
B
FIGURE 6.67 (A) Left-sided L5/S1 epidurogram, including the L5 nervegram and S1 nervegram in an A/P view. (B) L5/S1 epidurogram in a lateral view.
Lumbar Discography Introduction Lumbar discography is a diagnostic test that seeks to provide clinically relevant information about the source of a patient’s low back pain, with or without radiation to the lower extremity, that is not provided by other imaging techniques, such as magnetic resonance imaging (MRI). Radiographically, abnormal lumbar discs may or may not be associated with the patient’s symptoms.2 The outer annulus is richly innervated.3,4 Injection of dye within the substance of the pain-generating disc often reproduces the patient’s pain symptoms. This is particularly significant if the concordant pain is reproduced at low injection
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A H IZ
FIGURE 6.68 On the posterior aspect of the L23 and L45 disc is a bright spot known as a high intensity zone (HIZ).
pressures.5 The disc is comprised of three main regions: the nucleus pulposus, the annulus fibrosus, and the cartilaginous end plates. Mechanical stress is mostly distributed to the lumbar vertebral end plate, which is the disc’s source of nutritional supply. Disc degeneration is thought to be the result of repetitive mechanical stress to the disc, although this is not necessarily associated with direct trauma. Discogenic pain, i.e., pain emanating from within the disc, is often axial low back pain and is frequently aggravated by the assumption of certain body positions (e.g., prolonged sitting and valsalva). Patients with discogenic pain often have annular tears or fissures within the disc that contribute to their pain symptoms. Radiographically, these fissures may appear on the MRI as a “high-intensity zone” (HIZ) (Figure 6.68) on the T2 weighted image. This HIZ on the MRI represents a “radial” or “type II” annular tear. Radial tears are concentric fissures in the annular fibers. In the past, a HIZ was described as a reliable marker of painful disc disruption, but that concept has since been disputed.6–8 The presence of HIZs was noted in asymptomatic as well as symptomatic individuals.6 While MRIs give useful information on disc morphology, they are limited in their clinical application, as HIZs or other disc abnormalities are not always pain generators in an individual patient. The MRI cannot identify which disc is causing the patient’s pain. Performing a provocative discogram that recreates the patient’s exact (concordant) pain symptoms seeks to establish the pain-generating lumbar disc. Prior to performing discography, other sources of pain and spinal pathology should be ruled out with radiographic studies. Once these have been ruled out and a discogram is performed at least two discs must be evaluated. In order to have a valid provocative discogram, it is important to establish that there is a nonpainful (control) disc.9 A painful discogram at a single level without a nonpainful control discogram is a meaningless diagnostic test. Thus dicograms need to be performed at both the suspected pain generating disc and at a control disc. While there may be back discomfort as a result of intradiscal injection of contrast into a normal disc, an injection into a normal disc usually does not produce concordant pain symptoms. There are two types of information that may be obtained from lumbar discography: 1. The presence or absence of concordant pain in response to the injection of contrast (provocative discography) 2. Information regarding the disc morphology based on the way in which the contrast spreads.
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Provocative discography is the only means that we have to distinguish painful or symptomatic discs from those that are not sources of pain. There is a risk of false-positive results, and thus, patient selection is very important.10 Disc morphology can be further evaluated with a postdiscography computed tomography (CT), where contrast can be seen within the annular tears. The CT should ideally be performed within a few hours of the discogram to ensure adequate visualization of the contrast. Discography is not for everyone; discography on asymptomatic volunteers and patients with somatization disorder has reported high false-positive rates.10 Patients who report pain during a discogram performed on a nondisrupted disc are more likely to have elevated hypochondriasis, hysteria, and depression scores on the Minnesota Multiphasic Personality Inventory (MMPI).11 Indications: 1. 2. 3. 4.
Failure of all other diagnostic tests to provide the source of back pain Diagnosis of the source of back pain in patients who are surgical candidates or are candidates for intradiscal procedures Evaluation of the level above or below the level of a fusion Determination of symptomatic levels in a patient with multilevel disc disease
Contraindications: 1. 2. 3. 4. 5. 6.
Patient refusal Systemic infection Systemic anticoagulation Pregnancy Severe allergy to nonionic dye Severe spinal stenosis
Complications: 1. 2. 3. 4. 5. 6.
Back pain Discitis Arachnoiditis Damage to the disc Postdural puncture headache Meningitis
Equipment/Materials: 1. 2.
3. 4.
5. 6. 7. 8.
See the equipment and materials section at the beginning of this chapter — those listed below are in addition to those listed at the chapter’s beginning. With the exception of very thin patients, discography requires a longer needle than the 3½ in. spinal needle used for most other spinal injections. A 25-gauge 4 11/16 in. or 5 in. needle may be used in the average-sized patient. A 25-gauge discography needle with an introducer may be used. These are especially helpful in performing L5/S1 discograms. Alternatively, a long (7 in., 22-gauge) spinal needle may also be used for obese patients. Curving the needle at the distal tip in the direction of the needle bevel allows for easy navigation of the needle, particularly when attempting to enter the L5/S1 disc. Strict sterile technique is applied at all times; the needle should be kept within its sheath until the time of use. Avoid handling the needle tip prior to the insertion of the needle. A manometer is helpful when quantifying intradiscal pressures. It is also helpful when creating a chart to document intradiscal pressures. Prophylactic intravenous antibiotics, to be administered within 30 min of the procedure. Water-soluble, nonionic contrast dye. Although there is no literature showing added benefit, we also give patients both intradiscal antibiotics. The intradiscal antibiotics are given in combination with
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the injected contrast (e.g., 1 to 10 mg/ml cefazolin). Generally, no more than 3 ml of dye is injected into each disc. The patient should be given instructions on post-procedure expectations and possible complications.
Manometry Derby described using pressure-controlled discography to predict outcome. It provides a more quantitative description of the discography results.12 The opening pressure is that pressure at which dye was first observed within the disk space.5 A chemically sensitive disc is one that reproduces concordant pain at low disc pressures (<15 psi above opening pressure). A mechanically sensitive disc is one that reproduces concordant pain between 15 and 50 psi above opening pressure.5 Many practitioners use a 3 ml syringe and use tactile feedback to assess the injection pressure of dye into the disc as “low,” “intermediate or moderate,” or “high.” However, there are reports of discography resulting in the production of pain in asymptomatic volunteers. Manometry may help to prevent the injection of dye at very high pressures and the creation of a false-positive response (Figure 6.69).10
FIGURE 6.69 Examples of syringes used for manometry while performing discography.
Patient Preparation Intravenous cefazolin (Ancef) 1 g is administered within 30 min of the procedure. If the patient is allergic to cephazolin, clindamycin 900 mg intravenously may be used instead. Strict aseptic technique is used, with sterile preparation and drape of the patient’s back.
Sedation Discography is best performed with little to no sedation. A small amount of opioid once the procedure is finished is acceptable to alleviate discomfort secondary to the procedure. It is important to have the patient alert so that he or she may determine whether or not the discomfort that they feel is an exact reproduction of his or her usual pain symptoms. If there is concern about further documentation, then the pain physician may videotape the procedure, particularly the patient’s facial response to the injection.
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Preparation for Needle Placement 1. Which side is best to perform discography? Generally, the needle entry site is on the side contralateral to the pain. This will avoid conflicting responses from the needle trauma in determining concordant pain. 2. Which levels should be performed? The suspected pain generator disc should be studied; however, a nonpainful/normal control disc should always be studied as well. If all discs studied are painful, and there are no nonpainful discs, the study is less meaningful and more difficult to interpret. 3. On which side should the C-arm be positioned? The C-arm should be on the same side as needle entry, due to the exaggerated oblique angle that is often required for discography. This angle may be more than the C-arm is able to perform from the contralateral side. 4. Using fluoroscopy in the A/P view, count the vertebrae from T12 to ensure that you are injecting the correct disc. If there are more than five lumbar vertebrae, ensure that the intervertebral disc that you are studying is the same disc that you were asked to study.
Patient Position The patient is placed in the prone position on the procedure table (Figure 6.70A).
(A)
(B)
(C)
FIGURE 6.70 (A) The patient should be in the prone position on the procedure table with a lumbar support placed under the lower abdomen to reduce the natural lumbar lordosis. (B) Photographs of the lateral view of the oblique spine showing the needle insertion of the lumbar discography. (C) Magnified version of B.
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C-Arm Position 1.
The C-arm is positioned on the same side as the needle entry. Square off the vertebral end plates in the A/P view. If both the superior and inferior vertebral end plates cannot be squared off, then the superior end plate below must be square (Figure 6.70D).
(D) FIGURE 6.70 (continued). (D) The vertebral endplates are squared in the AP view.
2. 3.
Once the vertebral end plates are squared, the C-arm may be moved into the oblique view to prepare for needle entry. Move the C-arm laterally around the patient until the superior articular process (SAP) is in the center of the vertebral end plate. This usually creates a more oblique angle of the C-arm than would normally be used for an intra-articular facet joint or transforaminal injection. The marker in Figure 6.71 shows the needle entry site.
B A
FIGURE 6.71 (A) Photograph of the oblique view of the target lumbar vertebra. (B) The tip of the pointer shows the needle entry point. Note that the vertebral bodies are squared off and the superior articular process bisects the line created by the vertebral endplates.
4.
Sometimes moving the patient closer to the C-arm helps to facilitate this view.
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Needle Placement 1. 2.
The needle is inserted into the lumbar disc via the groove located lateral to the lower portion of the SAP (Figure 6.70B, Figure 6.70C, and Figure 6.71). Needle entry is in the oblique view just lateral to the SAP. If the needle remains lateral to the SAP, then far medial (intrathecal) needle placement will be avoided (Figure 6.72A).
Needle
(A) FIGURE 6.72 (A) The needle entry is just lateral to the superior articular process (SAP).
3.
The use of a curved-tip needle for enhanced control of the steering of the needle is recommended. Once the SAP is contacted, the needle tip may be rotated laterally, then advanced around the SAP, and guided into the center of the disc (Figure 6.72B).
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(B) FIGURE 6.72 (continued). ((B) The needle is just past the SAP and is about to enter the disc in the lateral view.
4.
There will be a change in resistance to advancement (like that of entering an eraser) once the annulus is pierced, which may result in transient back pain for the patient (Figure 6.73A).
(A)
FIGURE 6.73 (A) The needle has just entered the disc. The AP view will look something like the above image with the needle in the lateral aspect of the disc, still in the annulus. If you inject dye at this point, you will get an annulogram and not a discogram.
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6.
Once the disc is contacted, the C-arm is rotated from the A/P position to the lateral view. In order to avoid the needle piercing the anterior margin of the disc, we recommend advancing the needle in the lateral view. Early in the needle advancement, the A/P view of the needle in the disc may appear as shown in Figure 6.73B.
(B)
FIGURE 6.73 (continued). (B) In general you must advance the needle at least past the pedicle shadow to enter the nucleus in the AP view. If the needle is in the center of the disc in the lateral view but has this appearance on the AP view, then the needle is too anterior and lateral and must be redirected posteriorly and medially to access the center of the nucleus.
7.
8.
As we will discuss later in this chapter, it is possible to have excellent needle position in one view and discover that the needle is not within the nucleus. Thus, once the needle appears to be within the central aspect of the disc in the lateral view, an A/P view is repeated in order to verify that the needle is within the center of the disc in both views (Figure 6.74). Once you are satisfied that the needle is within the nucleus, then contrast is injected.
Potential Difficulties with Needle Placement (Annular Placement of the Needle) 1.
2.
3.
There are times when the needle appears to be in good position in one view, and upon viewing the needle position from another angle, it is apparent that the needle is in the annulus (the periphery of the disc) and not within the nucleus. If the needle is in the center of the disc in the lateral view but is not in the center of the disc in the A/P view, then the needle is too lateral and must be redirected posteriorly and medially in order to access the center of the nucleus. When advancing the needle, it is often easier to get the needle into the center of the disc if the needle is angled slightly posteriorly so that the needle will advance medially into the disc. If the needle is initially advanced at an acute angle, the result will be an annular placement and injection of dye. Both views need to be checked, as the needle may appear to be in good position in, e.g., the lateral view, but it may be too lateral in the A/P view, or vice versa. In both of those instances, the needle needs to be repositioned to avoid an annular injection. (See Figure 6.73C through Figure 6.73E.)
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The facetal column
(C)
The line of the medial margin of the facetal column
Posterior
Anterior
(D)
Anterior
(E) Posterior FIGURE 6.73 (continued). (C) Illustrates a needle that has not passed the facetal column in the AP view and thus has not entered the nucleus. (D and E) Demonstrate a needle that is placed too laterally within the disc and ends up in the anterior-lateral annulus. (D) Shows how the needle might appear in good position if seen via the lateral view. (E) Shows that when the same needle is visualized from the AP view it is seen to be too lateral within the disc space.
What does an annulogram look like under fluoroscopy? There is a characteristic angular appearance to an annulogram. The opening injection pressure is often greater than is seen with a discogram (Figure 6.74A through Figure 6.74C).
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(A)
(B)
FIGURE 6.74 (A) Lateral view of an annulogram. Note the box like appearance of the contrast in this lateral image. (B) AP view of an annulogram.
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(C)
FIGURE 6.74 (continued). (C) Image of an initial annulogram where the needle was repositioned and initial injection of contrast spread across the midline.
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Contrast Injection within the Disc Space 1.
The needle is in good position; verified in both A/P and lateral views (Figure 6.75A through Figure 6.75D).
(A)
(B)
FIGURE 6.75 (A) The needle is within the nucleus in the A/P view. (B) The lateral view of the 25-gauge needle within the nucleus.
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The end plates are not squared.
(C)
(D)
FIGURE 6.75 (continued). (C) This lateral image is not squared; it is a parallax view and it is difficult to tell whether the needle is in good position. (D) Two needles advanced into the disc in the lateral view.
2.
Aspirate the contrast containing antibiotic into the manometer syringe (if manometry is to be used). Check to ensure that it is set to psi (not atm); note how many milliliters of antibiotic containing contrast are contained within the syringe prior to starting. Turn the syringe handle, and note the pressure reading when dye first comes out of the needle. This is the opening pressure.
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Continue to inject dye into the disc, and watch for adequate spread of dye. Monitor the volume injected, the injection pressure, and the patient’s response. We recommend not injecting more than 3 ml of dye within the disc (Figure 6.76A, Figure 6.76B, and Figure 6.77).
(A)
(B)
FIGURE 6.76 (A) AP view of a normal discogram. (B) Lateral view of a normal discogram.
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FIGURE 6.77 AP view of a discogram at L3/L4.
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140 4.
5.
Record the pressure at which the patient reports pain. Also record the pain intensity and character using a verbal analog scale (0 to 10). Record how similar the pain is to the patient’s usual and customary pain (concordance). Record the morphology of the disc — whether it is normal or whether fissures are seen, or whether there is epidural spread. Epidural spread is best seen in the lateral view (Figure 6.78A and Figure 6.78B).
(A)
(B)
FIGURE 6.78 (A) Lateral view of contrast within the L3/4, L4/5 and L5/S1 discs. The arrow is pointing to the epidural extravasation of the contrast from the L3/4 disc space. (B) AP view of a discogram at L5/S1 with contrast spread across the disc.
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6. A normal disc will generally not hold more than 3 ml. After the provocative discography, an analgesic response may be observed after the intradiscal injection of a small quantity of local anesthetic. Intradiscal steroids have also been used with varying results. 7. The patient’s pain response: The key to pain assessment in provocative discography is determining whether the patient’s usual pain symptoms are reproduced during discography. Thus, particular attention must be paid to the patient’s pain response: a. Does the patient have concordant pain? That is, were the character and location of the patient’s pain reproduced with the discography exactly like the patient’s usual pain? Is the intensity of the pain produced by discography similar, less than, or greater than the patient’s usual pain? Rate both the pain intensity and concordance, e.g., 8/10 intensity and 10/10 concordance. b. Does the patient have discordant pain? That is, the character and location of the pain are not exactly like the patient’s usual pain, or the intensity is dissimilar to the patient’s typical pain. If the level to be studied produces discordant pain, then the discogram at this level is described as “indeterminate.” An example of how this is described is that the pain intensity was 8/10, and the concordance was 3/10. c. Is the injection painless? If so, then this is the control level. If all the levels injected are painless, then the discogram is negative.
Mechanically vs. Chemically Sensitive Discs Chemically sensitive discs are described as those discs producing concordant pain at less than 15 psi above the opening pressure. Pain reproduction at low injection pressures indicates a very sensitive annulus and is thought to be due to chemically sensitized nociceptors in the outer annulus.5 Mechanically sensitive discs produce concordant pain at 15 to 50 psi above opening pressure.
Discography at L5/S1 Discography at the L5/S1 level is more technically challenging than its more cephalad counterparts. This is especially true in male patients, as the male iliac crest tends to angle closer to the spine, making it more difficult to pass the needle into the L5/S1 disc space while avoiding the L5 nerve root. A more detailed description of the anatomy and its consequences is detailed in the section on L5/S1 transforaminal epidural steroid injections (Figure 6.62 and Figure 6.63). The likelihood of encountering the exiting nerve root is greater, and a curved needle is helpful to avoid paresthesias. The needle should be bent so that the bevel is cut in the same direction as the bend that you made in the needle. Some pain physicians use an intrathecal approach to access the L5/S1 disc if the oblique approach to the L5/S1 disc is technically impossible. The C-arm position is different than is seen for the levels above L5/S1. The cephalad to caudal tilt of the C-arm is such that the image intensifier is often very close to the patient’s torso (Figure 6.79).
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Positioning C-Arm Fluoroscopy The L5/S1 vertebral end plates are squared in the A/P view by positioning the C-arm as is depicted in Figure 6.79.
FIGURE 6.79 The C-arm is tilted toward the patient’s head so that the L5/S1 vertebral end plates are squared in the AP view.
Inserting a Needle The needle entry is performed in the oblique view. The C-arm should be rotated laterally until, if possible, a “triangle” is obtained (Figure 6.80). The borders of this triangle are outlined as follows:
FIGURE 6.80 Entry site for an L5/S1 discogram.
1. 2. 3.
Superiorly by the inferior border of the L5 vertebral body Medially by the lateral aspect of the SAP of S1 Laterally by the medial aspect of the posterior superior iliac crest
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The needle is then advanced via the opening provided by the triangular borders described above, cautiously avoiding the exiting L5 nerve root. The angle at which the needle is placed is from cephalad to caudad (Figure 6.81).
FIGURE 6.81 Lateral view of dye spread within disc.
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Once the needle is past the SAP of S1, the C-arm is rotated to the lateral view to allow for entry of the needle into the disc (Figure 6.82).
FIGURE 6.82 Lateral view of the needle in position for an L5/S1 discogram.
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Confirming the Needle Placement As with the levels above L5/S1, verify with an A/P view that the needle is within the nucleus (Figure 6.83).
FIGURE 6.83 The needle is in the center of the L5/S1 disc. There is contrast seen in the L4/L5 disc above.
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Injecting Contrast Inject contrast via the needle as was described for the other lumbar levels. Record the patient’s pain response and disc morphology as before. (See Figure 6.84 through Figure 6.86 for more detail.)
FIGURE 6.84 A discogram of a mature disc at L5/S1.
FIGURE 6.85 A circumferential annular tear is seen in this discogram.
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FIGURE 6.86 A lateral view of an L4/L5 and L5/S1 discogram.
When the disc height is reduced, discography at this level is more difficult, and the area through which the needle must traverse and avoid the nerve root is smaller. This is also compounded by the fact that the iliac crests in men are at a more acute angle, making the angle required to enter into the disc space steeper than that for women. This sometimes requires a greater bend of the needle; there are some practitioners that place two small bends in the needle to facilitate the more acute angle seen at this level. Sometimes the needle needs to enter the disc from a more lateral approach in order to be placed in the center of the disc. This may be done either by having a more lateral entrance to the “triangle” described above or by directing the needle more laterally once it is past the iliac crest and then redirecting medially toward the disc space. Finally, in patients with particularly difficult anatomy, there is the option of advancing the needle through the intrathecal space directly into the disc. The needle should be advanced into the center of the disc in the lateral view as before. When checking the A/P view, the bodies should be square (Figure 6.16A and Figure 6.16B), recalling that the C-arm tilt needed for needle entry was much greater than that needed for the more cephalad levels.
Post-Procedure It is prudent to supply the patient with post-procedure information cautioning them to avoid activities that increase disc pressure for the hours following discography (e.g., avoid straining). They should be cautioned on warning signs of discitis (e.g., fever, increased back/leg pain that is not their usual pain) or cauda equina syndrome. They should be warned that some back discomfort is normal, but a marked increase in back pain that is different from their usual pain, especially in the presence of fever, warrants further investigation.
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Bibliography 1. Manchikanti, L., Pampati, V., Bakhit, C.E., Rivera, J.J., Beyer, C.D., Damron, K.S., and Barnhill, R.C. Effectiveness of lumbar facet joint nerve blocks in chronic low back pain: a randomized clinical trial. Pain Physician 4, 101–117, 2001. 2. Jensen, M.C., Brant-Zawadzki, M.N., Obuchowski, N., Modic, M.T., Malkasian, D., and Ross, J.S. Magnetic resonance imaging of the lumbar spine in people without back pain. The New England Journal of Medicine 331, 69–73, 1994. 3. Sullivan, W.J., Willick, S.E., Waree, C.A., Zuhosky, J., Tyburski, M., Dreyfuss, P., Prather, H., and Press, J.M. Incidence of intravascular uptake in lumbar spinal injection procedures. Spine 25(4), 481–486, 2000. 4. Knight, J.W., Cordingley, J.J., and Palazzo, M.G.A. Epidural abscess following epidural steroid and local anesthetic injection. Anaesthesia 52, 576–578, 1997. 5. Derby, R. et al. The ability of pressure-controlled discography to predict surgical and nonsurgical outcomes. Spine 24(4), 364–372. 6. Schellhas, K.P., Pollei, S.R., Gundry, C.R., and Heithoff, K.B. Lumbar disc high-intensity zone: correlation of magnetic resonance imaging and discography. Spine 21(1), 79–86, 1996. 7. Carragee, E.J., Paragioudakis, S.J., and Khurana, S. 2000 Volvo Award Winner in Clinical Studies. Lumbar high-intensity zone and discography in subjects without low back problems. Spine 25(23), 2987–2992, 2000. 8. Aprill, C.N. and Bogduk, N. High-intensity zone: a diagnostic sign of painful lumbar disc on magnetic resonance imaging. Br J Radiol 65, 361, 1992. 9. North American Spine Society. Position statement on discography. Spine 13, 1343, 1988. 10. Carragee, E.J., Tanner, C.M., Yang, B., Brito, J.L., and Truong, T. False-positive findings on lumbar discography. Reliability of subjective concordance assessment during provocative disc injection. Spine 24(23), 2542–2547. 11. Block, A.R., Vanharanta, H., Ohnmeiss, D.D., and Guyer, R. Discogenic pain report: influence of psychological factors. Spine 21(3), 334–338, 1996. 12. O’Neill, C. and Kurgansky, M. Subgroups of positive discs on discography. Spine 29 (19), 2134–2139, 2004. 13. Dreyfuss, P., Schwarzer, A.C., Lau, P., and Bogduk, N. Specificity of lumbar medial branch and L5 dorsal ramus blocks: a computed tomographic study. Spine 22, 895–902, 1997. 14. van Kleef, M., Barendse, G.A.M., Kessels, A., Voets, H.M., Weber, W.E.J, and de Lange, S. Randomized trial of radiofrequency lumbar facet denervation for chronic low back pain. Spine 24 (18), 1937–1942, 1999. 15. Bogduk, N. and Long, D.M. The anatomy of the so-called “articular nerves” and their relationship to facet denervation in the treatment of low-back pain. Journal of Neurosurgery 51, 172–177, 1999. 16. Lutz, G.E., Vad, V.B., and Wisneski, R.J. Fluoroscopic transforaminal epidural steroid injections: an outcome study. Arch Phys Med Rehab 79, 1362–1366, 1998. 17. Weiner, B.K. and Fraser, R.D. Foraminal injection for lateral lumbar disc herniation. J Bone Joint Surg 79B, 804–807, 1997. 18. Hopwood, M.B. and Abram, S.E. Factors associated with failure of lumbar epidural steroids. Regional Anesthesia 18, 238–243, 1993. 19. Hogan, Q.H. Lumbar epidural anatomy, A new look by cryomicrotome section. Anesthesiology 75, 767–775, 1991. 20. Guyer, R.D. and Ohnmeiss, D.D. Lumbar discography. Spine (3 suppl), 11S–27S, 2003 21. Bogduk, N. Lumbar discography. Spine 21(3), 402–404. Feb 1996. 22. Coppes, M.H., Marani, E., Thomeer, R.T.W.M., and Groen, G.J. Innervation of “painful” lumbar discs. Spine 22(20), 2342–2350, 1997. 23. Fagan, A., Moor, R., Roberts, B.V., Blumbergs, P., and Fraser, R. ISSLS Prize Winner: The Innervation of the Intervertebral Disc: A Quantitative Analysis. Spine 28(23), 2570–2576, 2003.
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24. Recommendations for Lumbar Discography. ISIS Newsletter, December 1997, pp. 80–91. 25. Jensen, M.C., Brant-Zawadzki, M.N., Obuchowski, N., Modic, M.T., Malkasian, D., and Ross, J.S. Magnetic Resonance imaging of the lumbar spine in people without back pain. The New England Journal of Medicine 331, 69–73, 1994.
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Fluoroscopic Images of the Cervical Spine
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Positioning the Patient Cervical spinal injections can be done in either the supine (Figure 7.1A), prone (Figure 7.1B), or lateral positions (Figure 7.1C).
A
B
C
FIGURE 7.1 Cervical spine injection positions. (A) Supine position. (B) Prone position. (c) Lateral position.
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Positioning the C-Arm The C-arm can be positioned in many ways for cervical spinal injections (Figure 7.2). For example, the C-arm can be positioned from the patient’s side, as when performing lumbar procedures (Figure 7.2A). The C-arm can also be positioned from behind the patient’s head (Figure 7.2B). The C-arm can be positioned to get a lateral view of the cervical spine as seen in Figure 7.2C and Figure 7.2D.
A
B
C
D FIGURE 7.2 C-arm positions. (A) At side. (B) At patient’s head. (C) and (D) Positioned for lateral view of cervical spine.
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A/P (P/A) View and Lateral View of the Cervical Spine Images of both the anterior–posterior (A/P) view in the prone position, the posterior–anterior (P/A) view in the supine position and the lateral view of the cervical spine, look quite different from images of the A/P and lateral view of the lumbar spine (Figure 7.3). This is due to the unique shapes of the cervical vertebrae. B
A
C
D
Mandible
FIGURE 7.3 The cervical and the lumbar spine. (A) P/A view of the cervical spine. (B) A/P view of the lumbar spine. (C) Lateral view of the cervical spine. (D) Lateral view of the lumbar spine.
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Comparison of Cervical Vertebrae and Lumbar Vertebrae Like a lumbar vertebra (Figure 7.4B), a cervical vertebra (Figure 7.4A) consists of the vertebral body, two transverse processes, two pedicles, lamina, two superior articular processes, two inferior articular processes, and a spinous process. However, the cervical vertebra differs from the lumbar vertebra. Their differences are summarized in Table 7.1. Figure 7.5 is a P/A view image of the cervical spine.
A
B
C D
FIGURE 7.4 (A) Cervical vertebra (superior view). (B) Lumbar vertebra (superior view). (C) Lateral view of the cervical spine from C4 to C7. (D) Lateral view of the lumbar vertebra.
TABLE 7.1 Comparison of Cervical Vertebrae and Lumbar Vertebrae Cervical Vertebra
Lumbar Vertebra
Vertebral body
Small
Large
Transverse process
Quite small Connects to lateral surface of vertebral body Anterior to the pedicle Has transverse foramen Anterior to the superior articular process
Large Connects to posterior surface of vertebral body Posterior to the pedicle Lateral to the superior articular process
Pedicle
Short Connects to posterior surface of transverse process
Long Connects to posterior surface of lumbar vertebral body
Spinous process
Varies in length Ends in two tips (called bifid tips)
Long Ends in only one tip
Superior articular process
Connects to pedicle only
Connects to pedicle and transverse process
Inferior articular process
Articular pillar connects the superior and inferior articular processes
Pars interarticularis (part of lamina) connects to superior and inferior articular processes
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4
3 2
1 FIGURE 7.5 Fluoroscopic image of the P/A view of the cervical spine. (1) Spinous process, (2) transverse process with transverse foramen, (3) articular pillar, (4) vertebral body.
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Lateral and Oblique Views of the Cervical Spine Figure 7.6 is a lateral fluoroscopic image of the cervical spine. We usually rotate the fluoroscopic image horizontally if the patient is in a supine position (Figure 7.7).
Mandible
3
6
2 1 4
7 5
FIGURE 7.6 Fluoroscopic image of the lateral view of the cervical spine. (1) Spinous process, (2) articular pillar, (3) superior articular process, (4) inferior articular process, (5) vertebral body, (6) pedicle, (7) transverse process with transverse foramen.
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Mandible
6 5
2
3
1
4
FIGURE 7.7 Fluoroscopic image of the lateral view of the cervical spine (rotation of fluoroscopic image in Figure 7.6). (1) Spinous process, (2) articular pillar, (3) superior articular process, (4) inferior articular process, (5) vertebral body, (6) transverse process with transverse image of the foramen.
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In true lateral images of the cervical spine (Figure 7.8), the vertebral body is squared, the articular pillar is a trapezoid shape, the facet joint space is open, the transverse process with transverse foramen cover the posterior–superior portion of the vertebral body, and the spinous process has sharp superior–posterior and inferior margins.
Mandible
Transverse processes with transverse foramina cover posterior–superior portion of vertebral body
Vertebral body is squared off Vertebral body Transverse process with transverse foramen Articular pillar Spinous process A trapezoid shape of Articular pillar
Spinous process has sharp margins
FIGURE 7.8 Lateral images of cervical spine.
Facet space is open
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Figure 7.9 illustrates the comparison between the true lateral view and the false lateral view of the cervical spine images. The left column illustrates true lateral view images. The right column illustrates the false lateral images.
A
B Mandible
C
D
E
FIGURE 7.9 (A) True lateral image. (B–F) False lateral images.
F
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It is very difficult to identify intervertebral foramina on the lateral image of the cervical spine compared with the lateral image of the lumbar spine (Figure 7.10). This is because the cervical transverse processes complex opacifies the image of intervertebral foramen. However, if we view the cervical spine obliquely and inferiorly (Figure 7.11), we can visualize the intervertebral foramina easily.
Mandible
Transverse processes cover intervertebral foramens
A
Intervertebral foramens
B
C FIGURE 7.10 (A, B) Lateral images of the cervical spine. (C) Lateral image of the lumbar spine.
Fluoroscopic Images of the Cervical Spine
A
B
FIGURE 7.11 (A) Photo of inferior and oblique views of the cervical spine. (B) Photo of the lateral view of cervical spine.
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A unique oblique image of the cervical spine (Figure 7.12) can be obtained by tilting the C-arm to the injecting side about 45˚ and rotating caudally about 20 to 30˚ (Figure 7.13).
Mandible
FIGURE 7.12 Right-sided obliquely viewed fluoroscopic image of the cervical spine.
FIGURE 7.13 The C-arm positions required to obtain a fluoroscopic image of the cervical spine shown in Figure 7.12.
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Cervical Intervetrebral Foramina and the Cervical Spinal Nerve Roots There are eight cervical spinal nerve roots and only seven cervical vertebrae. There is no intervertebral foramen between C1 and C2. The first visualized cervical intervertebral foramen is between C2 and C3. The C3 spinal nerve root travels via this foramen (Figure 7.14). The vertebral artery goes via the transverse foramina, usually from the C6 foramen to the C1 foramen into the skull (Figure 7.15A and Figure 7.16A). The possible locations of the vertebral artery are demonstrated on the laterally and obliquely viewed fluoroscopic images of the cervical spine (Figure 7.15B and Figure 7.16B).
Mandible
The foramen between C2 and C3
There is no foramen between C1 and C2 FIGURE 7.14 Method for counting intervertebral foramina and cervical spinal nerve roots.
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Mandible
A Vertebral artery B Vertebral artery FIGURE 7.15 Location of the vertebral artery on the lateral view of the cervical spine.
Mandible
A Vertebral artery
B Vertebral artery FIGURE 7.16 Location of the vertebral artery on the obliquely viewed cervical spine.
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Bibliography Bontrager, K.L. and Anthony, B.T., Eds., Textbook of Radiographic Positioning and Related Anatomy, 2nd ed., C.V. Mosby Company, St. Louis, MO, 1990. Brown, D.L., Ed., Atlas of Regional Anesthesia, 2nd ed., W.B Saunders, Philadelphia, 1999. Clemente, G.D., Ed., Gray’s Anatomy, 13th ed., Lea & Febiger, Philadelphia, 1984. Fenton, D.S. and Czervionke, L.F., Eds., Image-Guided Spine Intervention, W.B. Saunders, Philadelphia, 2003. Netter, F.H., Ed., Atlas of Human Anatomy, Ciba Geigy Corporation, 1989. Waldman, S.D., Ed., Atlas of Interventional Pain Management, 2nd ed., W.B. Saunders, Philadelphia, 2004.
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Cervical Injections
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In this chapter, we will discuss injections around the cervical spine for the relief of pain due to headaches, neck pain, shoulder pain, and arm and hand pain. We will first begin with cervical facet injections, both intra-articular and medial branch injections and radiofrequency denervation, and we will then proceed to cervical epidural and nerve root injections. Both interlaminar and transforaminal epidural steroid injections will be discussed. The pain physician should be very familiar with lumbar injections prior to attempting any injections in the neck. Familiarity with airway management is also recommended for physicians who perform cervical spinal injections.
Preparation for the Performance of Cervical Injections Patient preparation: We advise the patients to have no solid foods for a minimum of 6 h, particularly prior to cervical injections. We recommend that the patients have another individual available to transport them home following the procedure. Sterile preparation and drape are required; preparation above and below the hairline may be required, particularly for the upper cervical injections. Monitor the patient’s heart rate, blood pressure, and oxygen saturation. The American Society of Regional Anesthesia and Pain Medicine (ASRA) guidelines report no evidence of additional risk for patients taking nonsteroidal anti-inflammatory drugs (NSAIDs) who received spinal or epidural analgesia.1 However, when performing cervical transforaminal injections, it is the author’s practice, as a precaution, to ask the patients not to take aspirin for 7 to 10 d prior to the procedure and not to take NSAIDs (with the exception of COX-2 inhibitors) the day of the procedure. Equipment/Materials: •
• • • •
• •
• •
A 22- or 25-gauge 3½ in. spinal needle, with or without a distal curved tip in the direction of the bevel, is used for most cervical procedures performed in the prone position. A 25-gauge, 2 in. spinal needle is adequate for the vast majority of cervical foraminal and facet injections that are performed with the patient in the supine position. It is very rare, even in obese patients, to require a 3½ in. spinal needle for cervical transforaminal injections. Intravenous (IV) access for all cervical transforaminal injections as a safety precaution in the event of intravascular injection. Oxygen delivered at low flows via nasal cannula is suggested. Water-soluble nonionic dye. Local anesthetic (e.g., 0.25 to 0.5% bupivacaine or 2% lidocaine) and steroid for a total of 1 ml or less of injectate. Note that the local anesthetic and steroid may be injected together as a combined solution or separately. We recommend using the least particulate steroid available for transforaminal epidural steroid or selective nerve root injections. Steroids are not necessary for medial branch injections. A syringe (or syringes) for injecting the local anesthestic and steroid. A 3 ml or smaller is recommended; a 10 ml syringe is too large and will generate too much pressure with aspiration and risk inadvertent vascular injection. Connection tubing to allow for contrast injection without fluoroscopy exposure to the hands. This also facilitates an immobile needle. Lidocaine (0.5 to 2%) and a 25- to 27-gauge needle for local infiltration. We do not recommend the use of needles greater than 1 in. for skin infiltration for cervical procedures, particularly in thin patients. We recommend very superficial, subcutaneous injections of local anesthetic to avoid intravascular or brachial plexus injections.
Sedation: Light sedation is recommended, e.g., with midazolam 1 to 2 mg intravenously.
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Cervical Facet Injections Headaches and pain felt in the neck, shoulders, and upper back may originate in the upper, middle, and lower cervical facets, respectively.2,3 Cervicogenic headaches differ from vascular headaches both in their symptoms and in the origination of cervicogenic headache from the posterior superior neck. These headaches may also be reproduced by palpation of the painful facet joint, with lateral neck movement, and particularly with neck extension. Cervicogenic facet and radicular pain are similar in character when originally from the upper cervical levels (C1–C4). The C2/C3 joint was reported to be a source of headaches following whiplash injury. Excellent response has been reported for relief of these headaches from lesions of the third occipital nerve, which innervates the C2/C3 facet joint.4 Below C4, cervical facet pain radiates to the shoulder and upper back; while cervical radiculopathy involving the C5 root and below involves the shoulder then radiates distally to the arm (Figure 8.1).
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C1 (atlas)
C2 (axis)
C7
T1
FIGURE 8.1 The cervical spine, viewed from the lateral approach. The needles indicate the target areas for both medial branch and intraarticular facet injections on the left side.
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Intra-Articular Facet Injections C1/C2 Joint Injection The C1/C2 or atlantoaxial (AA) joint (Figure 8.2A) receives innervation from the C2 nerve root. Pain, generally posterior headaches, that comes from the C1/C2 joint is generally localized to the suboccipital region and may be exacerbated with neck rotation. Pain coming from the upper cervical facets is more often manifested as headache rather than neck pain.5 The C-arm should be adjusted in order to obtain the clearest view into the joint. The angulation of the C1/C2 joint is not as caudal as it is in the lower cervical facets. The vertebral artery is just lateral to the C1/C2 joint; thus. the needle should stay medial to the lateral border of the C1/C2 joint at all times. If the needle enters medial to the junction of the lateral one third of the joint, the likelihood of an intrathecal injection increases (Figure 8.2B).
(A)
Atlantoaxial (AA) joint
(B) FIGURE 8.2 (A) Photograph of a spine model of the C1/C2 joint. (B) The spine with the C1/C2 joint marked.
Indications: 1. 2.
Neck pain with associated posterior headache Upper neck pain exacerbated by neck movement
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Contraindications: 1. Patient refusal 2. Systemic anticoagulation or coagulopathy 3. Systemic or localized infection at the site 4. Unstable cervical spine
Patient position: The patient is placed in the prone position; a pillow may be placed under the chest to allow for slight neck flexion (Figure 8.3).
A pillow under the chest FIGURE 8.3 The patient position for C1/C2 intraarticular injection.
C-arm position: 1. 2.
3.
The C-arm is placed at the head of the bed in front of the patient (or, alternatively, it may be at the patient’s side). If the image intensifier is at the head, then it is rotated approximately 20˚ toward the head to get an anterior–posterior (A/P) view of the joint. This is best accomplished with the patient’s mouth open. Adjust the image intensifier angle until a sharp image of the AA joint is visualized. We recommend saving copies of the A/P and lateral views showing the location of the needle tip before and after the injection of contrast into the joint.
Procedure: 1. 2. 3. 4. 5. 6.
The patient’s posterior occipital region is prepped in a sterile fashion above and below the hairline and then draped. The C-arm is positioned as described above. A 22- or 25-gauge, 3½ in. spinal needle is used. A slight curved tip often makes the needle easier to steer and allows for “bevel control.” It is easier to visualize the AA (C1/C2) joint if the patient’s mouth is open (Figure 8.4A and Figure 8.4B). The needle is advanced from the caudal aspect of the AA joint and enters the joint at the junction of the lateral one third and medial two thirds of the joint in the A/P view. The needle depth is ascertained in the lateral view, and the needle tip position within the AA joint is determined in the A/P view.
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(A)
(B) FIGURE 8.4 (A) C1/C2 view with mouth closed. The needle is seen entering the left C1/C2 joint. (B) C1/C2 view with mouth open to make visualization easier. The needle is seen entering the left C1/C2 joint space.
7. 8.
Advancing in the A/P view increases the likelihood that the needle will stay in the correct location within the joint space. Verify the needle depth periodically with lateral views (Figure 8.5).
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(A)
(B) FIGURE 8.5 (A) Lateral view of the C1/C2 joint, with the needle approaching the joint. (B) The needle has advanced toward the C1/C2 (AA) joint in the lateral view.
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(C)
(D) FIGURE 8.5 (continued) (C) The needle continues to advance into the C1/C2 joint in the lateral view. (D) Photograph of a cervical spine model viewed from the lateral aspect.
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9. After negative aspiration, <0.5 ml of nonionic contrast dye into the joint is recommended to verify the correct needle position (Figure 8.6).
FIGURE 8.6 Examples of A/P views of dye within the left C1/C2 joint space.
10.
11.
The joint space is entered inferiorly and then walked in. The target is the junction between the lateral one third and medial two thirds of the joint space. A small volume of local anesthetic and steroid is injected into the joint space after negative aspiration. After negative aspiration, the combination of local anesthetic and steroid is then injected carefully into the joint.
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180 Complications: 1. 2. 3. 4.
Injection into the vertebral artery, venous plexus, or cerebrospinal fluid (CSF) of air, local anesthetic, or steroid Injection into the foramen magnum or spinal cord Laceration of the vertebral artery Cerebellar hemorrhage or infarction
C2/C3 to C6/C7 Intra-Articular Joint Injections Pain from the C2/C3 to C4/C5 facets is felt in the neck and upper shoulders.6,7 Below this level, the pain spreads distally down the upper back and scapulae. The symptoms are increased with neck extension and lateral bending and may be reproduced with palpation of the facet joints, particularly when palpated from a slightly lateral direction. Contraindications: 1. Patient refusal 2. Systemic anticoagulation or coagulopathy 3. Systemic or localized infection at the site 4. Unstable cervical spine
Patient position: Intra-articular injections of the C2/C3 to C6/C7 facet joints may be performed in the prone, lateral, or supine positions. In the supine and lateral positions, the lateral view is used; in the prone position, the A/P view is used. C-arm position: 1.
From the supine position: a. The C-arm may either be perpendicular to the patient’s head or in line with the patient when it is positioned behind the patient’s head. b. It is important to keep the patient’s head looking up toward the ceiling to keep the head in neutral position. c. Tilt the C-arm to get a lateral view showing clear joint lines without an overlapping shadow from the contralateral joint (Figure 8.7).
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(A)
(B) FIGURE 8.7 (A) The patient is supine and the C-arm is aligned for a lateral image. (B) The patient is in the lateral position and the C-arm is aligned for a lateral image.
2.
d. It is important to get a true lateral view with even joint space margins when performing these injections (see Chapter 7, Figure 7.9), otherwise, the needle may venture posteriorly and medially, resulting in intrathecal injection or cord injury. The needle tip position should be verified in both the A/P and lateral views, even if it “feels” as though it is in the joint. From the prone position: a. The prone position has advantages in the performance of bilateral intra-articular cervical facet injections. When bilateral injections are performed in the supine position, the contralateral needle may obscure visualization once contrast is injected. In the prone position, there is no overlapping image from the contralateral side. b. The cervical facets are slanted in a slightly caudad direction.
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c. The C-arm is rotated forward so that the image intensifier is toward the feet, and the joint space appears to be more open (Figure 8.8).
(A)
(B) FIGURE 8.8 (A) Diagram of the patient in the prone position. (B) Diagram of the correct C-arm alignment with the patient in the prone position.
d. The needle entry is from slightly caudal to the cervical facet joint. e. It may sometimes be necessary to slightly rotate the patient’s neck to the contralateral side in order to better visualize the joint space. f. The needle entry is at the lateral one third of the joint. g. Stop advancing the needle once change in resistance is felt and the joint space is entered. h. In the prone position, the A/P view is used for the needle approach to the joint, and the lateral view is used to check the needle depth (Figure 8.12). Procedure: 1.
From the supine position: a. The lateral fluoroscopic view is used for needle entry. b. Needle entry is at the inferior to middle aspect of the joint space and is advanced into the radiolucent joint space, keeping the needle tip over the joint space at all times (Figure 8.9A). c. Once the change in resistance is felt and the joint space is entered, stop advancing the needle.
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(A) FIGURE 8.9 (A) Needle entry site for cervical intraarticular injection. The needle is pointing to the C3/4 facet joint.
d. The needle tip position is verified in both the A/P and lateral views, even if it “feels” as though it is in the joint (Figure 8.9B).
(B) FIGURE 8.9 (continued). (B) The needle is in the correct location within the joint in the P/A view.
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(A)
(B) FIGURE 8.10 (A) The needle has entered the joint. Note that due to the tunnel vision, the needle is exactly in line with the beam of the C-arm. (B) A small amount of dye has been injected into the joint and can be seen to spread within the joint space.
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If the capsule is disrupted, there may be epidural spread (Figure 8.11).
(A)
(B) FIGURE 8.11 (A) P/A view of an intraarticular facet injection with dye spread along the joint. (B) P/A view of an intraarticular facet injection with dye spread in the joint and dispersing into the epidural space.
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FIGURE 8.12 Intraarticular injection performed in a patient in the prone position, with dye spread along the joint space.
g. For injection, <1 ml of a solution of local anesthetic and steroid is recommended. h. A small amount of nonionic contrast injected into the joint space verifies the position of the needle. i. If the capsule is disrupted, there may be epidural spread. j. A solution of local anesthetic and steroid, <1 ml, is injected.
Cervical Medial Branch Injections Cervical medial branch injections may be performed in either the prone or supine position, utilizing A/P, lateral, or oblique approaches.8 The cervical facets may be anesthetized with a local anesthetic blockade of the medial branches of the dorsal rami of the spinal nerves that supply each joint. The typical location of the medial branches is in the center of the trapezoid formed by the lateral aspect of the facet. This is most often seen at the C4 and the C5 medial branches that innervate the C4/C5 facet joint (Figure 8.13). Medial branch injections are performed as a diagnostic tool prior to the performance of radiofrequency denervations of those nerves. The cervical facet joint is innervated by the medial branches of the nerves above and below that joint. For example, the C4/C5 facet joint is innervated by the medial branches of the C4 and C5 dorsal rami of the C4 and C5 spinal nerves. Thus, in order to anesthetize the C4/C5 facet joint, two injections must be performed. When using the oblique approach for medial branch injections or denervations, the needle entry is slightly below (posterior to) the foramen in the oblique view. The target site is at the base of the superior articular process in the oblique view and in the center of the waist of the vertebra in the posterior– anterior (P/A) view. In the lateral view, it is in the center of the image that has the appearance of a trapezoid. In the lateral view of the lower cervical facets, the medial branches have been described to lie in the superior aspect of the waist of that trapezoid.
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C1
C2
Cervical medial branches
T1 (A)
FIGURE 8.13 (A) Model of the lateral cervical spine labeled with the positions of the cervical medial branches.
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(B) Cervical medial branch is located in the center of the trapezoid FIGURE 8.13 (continued) (B) Diagram of the target point for cervical medial branches in the center of the trapezoid.
Contraindications: 1. Patient refusal 2. Systemic anticoagulation or coagulopathy 3. Systemic or localized infection at the site 4. Unstable cervical spine
Patient position: This procedure may be performed with the patient in the supine, lateral decubitus, or prone position. The supine position is commonly used for most of the cervical procedures that we perform. C-arm position: A more detailed description of C-arm positioning is found in Chapter 7. In all of the injections described in this book, it is imperative that the image on the screen is a clear representation of the target area. Refer to Chapter 7 for details on how to get a properly aligned fluoroscopic image of the cervical spine in the lateral, P/A and A/P, and oblique views. 1.
This procedure is easier to perform with the C-arm at the head of the patient and the patient in the supine position. Unless otherwise specified, all of the descriptions below will refer to the patient in the supine position.
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The cervical medial branches may be approached from the lateral, prone, or oblique view. Lateral approach: a. The patient is in the supine position with the head facing the ceiling (Figure 8.7A). b. Square off the cervical facet joints with the C-arm in the lateral view. Oblique approach (Figure 8.14):
FIGURE 8.14 Diagram of the oblique C-arm position for cervical medial branch injections.
a. Square off the cervical end plates in the A/P view by moving the image intensifier approximately 20˚ toward the feet. b. Then, move the C-arm between 45 and 50˚ until the contralateral transverse foramen are just below the superior border of the vertebral bodies, and the ipsilateral transverse foramen appear as dark ovals on the posterior aspect of the spine. This view is slightly different from the oblique view used for cervical transforaminal injections. In this view, the contralateral transverse foramina are more posterior to the border of the vertebral bodies than is seen in the view for the cervical transforaminal injections.9 c. The cervical foramen should be easily visualized in this view.
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Prone approach: a. The head may be in the neutral position, facing down; the neck should not be extended. b. The C-arm is rotated forward until the best view of the joints is seen. c. The posterior approach must be used to access the C8 medial branch, and we recommend it for C7 medial branch radiofrequency denervations as well.
Procedure: 1.
Lateral approach (Figure 8.7A, Figure 8.13, Figure 8.15)):
FIGURE 8.15 Lateral view of a cervical medial branch injection.
a. The needle entry is at the center of the trapezoid seen in the lateral view. This is best seen with the C4 and C5 levels. b. The needle depth is checked in the A/P view, and the location of the needle tip with respect to the facet is checked in the lateral view. c. In the A/P view, the needle is seen in the lateral concavity of the cervical facetal column. The needle should not be medial to this lateral border. d. The medial branches of the C3, C6, and C7 dorsal rami lie more superiorly along the trapezoid. e. The needle tip should be advanced on top of bone (the trapezoid) to avoid entry into the epidural or intrathecal spaces. 2. Oblique approach: a. Needle entry is slightly below the foramen and angled anteriorly. b. The needle tip should be advanced on top of bone as much as possible. Posterior placement of the needle during advancement increases the possibility of a medial (epidural or intrathecal) needle position. c. The needle is advanced until it hits bone. d. The needle position may be checked in the lateral view. e. The needle position is also verified in the A/P view to ensure that it is lateral to the cervical facet shadow (Figure 8.16).
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FIGURE 8.16 P/A view of a cervical medial branch injection. Note that the needle is in the waist of the cervical facet in this view.
3.
Prone approach: a. Target the depression or “waist” seen on the A/P view of the cervical facet that represents the lateral aspect of the facetal column. b. Once bone is contacted, rotate the C-arm to obtain a lateral view, and advance the needle to the center of the trapezoid, staying close to bone at all times. A “true” lateral view is very important. c. In patients with short necks, a lateral view may not be possible, as the shoulder obscures the view. Needle depth is then difficult to assess. In those cases, the needle should remain on the posterolateral aspect of the facetal column. Ensure that the A/P view being used is aligned correctly. d. A small volume (e.g., 0.3 ml) of local anesthetic is injected at each level after negative aspiration. e. Consideration should be given to injecting a small amount of contrast prior to injection of local anesthetic to avoid intravascular injection.
Cervical Medial Branch Radiofrequency Denervation Significant pain relief lasting 6 to 15 months has been observed with radiofrequency denervation of the medial branches of the cervical dorsal rami supplying the facet joints.7 If the patient receives significant (>70%) pain relief from diagnostic facet injections, they are good candidates for radiofrequency denervation.10–13 Again, at least two levels need to be lesioned in order to denervate a single joint, i.e., lesions need to be performed at both the C3 and C4 medial branches in order to denervate, e.g., the C3/C4 joint. The superficial branch to the C2/C3 joint, the third occipital nerve, is larger than the other medial branches and, thus, requires multiple lesions to adequately denervate.10–12,14
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Radiofrequency Denervation: (C3 to C8) Medial Branches The needle placement for radiofrequency denervation differs from that of facet injections in that the goal is to maximize the lesion size and efficacy. There are two kinds of radiofrequency lesions: heat (destructive) lesions and pulsed (nondestructive) lesions. Both may be used in the cervical spine. Equipment/Materials: The equipment and materials for radiofrequency denervation are different than those for other cervical injections. 1.
2. 3. 4. 5. 6.
A 5 cm radiofrequency needle with 5 mm or smaller active tip; curved or straight needle tip. A radiofrequency generator, a dispersive pad placed on the patient’s lower extremity, and a radiofrequency electrode. In some rare instances, there may be a patient with a very thick neck, where a 5 cm needle is not long enough and a 10 cm needle may be used, preferably with a 5 mm active tip. Oxygen delivered at low flows via nasal cannula. Local anesthetic (e.g., 0.5% bupivacaine or 2% lidocaine). A 3 ml syringe. Lidocaine (1%) and short (<1 in. needle) 25- or 26-gauge needle for superficial local infiltration in order to avoid intravascular or brachial plexus injection. IV access is obtained to provide mild sedation, as the needles for these procedures are larger than those used for diagnostic injections.
Contraindications: 1. Patient refusal 2. Systemic anticoagulation or coagulopathy 3. Systemic or localized infection at the site 4. Unstable cervical spine Procedure: 1.
Lateral approach (Figure 8.7A): a. The needle entry is at the center of the trapezoid shape created by the lateral image of the cervical facet. This is best seen at the C4 and C5 levels. b. The needle depth is checked in the A/P view, and the location of the needle tip with respect to the facet is checked via the lateral view. c. In the A/P view, the needle is seen in the lateral concavity of the cervical facet. It should not be medial to this shadow. d. The medial branches of the C3, C6, and C7 dorsal rami lie more superiorly along the trapezoid of the articular pillar. There is both a superficial branch and a deep branch of the C3 medial branches. The deep medial branch innervates the C3/C4 facet, and the large superficial medial branch (the third occipital nerve) innervates the C2/C3 facet.3,13,15 e. The needle tip should be advanced on top of bone (the trapezoid) to decrease the likelihood of epidural or intrathecal needle position (Figure 8.17).
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(A)
(B) FIGURE 8.17 (A) The radiofrequency needles are approaching the cervical facets from the lateral view. (B) The radiofrequency needles are in place.
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Oblique approach: The approach is the same as that for cervical medial branch injections. The needle should be at the posterior inferior aspect of the foramen (Figure 8.18).
FIGURE 8.18 The needles are placed in the oblique view.
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As with medial branch blocks, lesions of the C7 medial branch are easily performed in the prone position. The C7 medial branch courses posteriorly around the C7 superior articular process, so it may be accessed posteriorly (Figure 8.19A and Figure 8.19B).
(A)
(B) FIGURE 8.19 (A) A radiofrequency lesion at the C7 medial branch, A/P view. (B) The needle location is confirmed in the lateral view.
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4.
Sensory and motor stimulation are performed and recorded: a. Sensory stimulation is performed at 50 Hz up to 1 V. We suggest recording the lowest voltage at which the patient feels sensation. The patient should not feel any sensation to their upper extremities or chest. b. Motor stimulation is then performed at 2 Hz up to 2 V. Stimulation should produce movement only in the neck, with no corresponding movement in the upper extremities or diaphragm. Again, we also suggest noting the lowest voltage at which the patient experiences motor stimulation. c. After sensory and motor stimulations are performed and you are satisfied that the needle is in good position, the lesion may be performed. 5. For lesioning, this author usually performs two radiofrequency lesions per level in the cervical region. The first lesion is performed under pulsed radiofrequency, followed by a more posterior heat lesion after the needle is withdrawn slightly. Performing the pulsed lesion prior to the heat lesion allows for sensory and motor stimulation of the second lesion, as no local anesthetic is required for the pulsed lesion. a. Heat lesion: A small amount (e.g., 0.3 ml) of lidocaine is injected into the needle 1 to 2 min prior to the lesion. A lesion at 80˚C for 60 to 90 sec is then performed after satisfactory sensory and motor stimulation, as above. b. Pulsed lesion: No local anesthetic is needed prior to performing this lesion, as this procedure is not painful to the patient. The voltage setting is generally 45 V, and the temperature is no greater than 42˚C. Temperatures above 45˚C are considered destructive. c. Note that it is thought that the needle position should differ for heat vs. pulsed lesioning: i. Heat lesion: The needle is placed as parallel as possible to the medial branch of the dorsal ramus. ii. Pulsed lesion: The needle should be placed as close as possible to the “tunnel vision” view, i.e., more perpendicular to the facetal column or trapezoid.
Cervical Epidural and Selective Nerve Root Injections There are two basic techniques for the performance of cervical epidural injections under fluoroscopy — the interlaminar and the transforaminal approaches. These techniques vary in both needle tip location and patient positioning.
Cervical Transforaminal Injections The transforaminal approach may be used from the C1/C2 to the C7/T1 foramina. Transforaminal injections are most often performed in the supine position, but the lateral decubitus position with the neck in neutral position has also been used. The technique described below utilizes the supine position. This is more comfortable for the patient and allows for more control of the position of the patient’s head. It is difficult to visualize the needle tip and to avoid pneumothorax with the transforaminal approach using the oblique view below the level of C7/T1. Transforaminal epidural steroid injections and selective nerve root injections differ in the volume of solution injected and the location of the contrast spread. The selective nerve root injection, considered a diagnostic block, attempts to place the solution selectively along the nerve root while avoiding the epidural space. It is performed by injecting a small amount of contrast by the foramen, allowing for spread along the nerve root. This is followed by injecting a similar volume of local anesthetic through the needle. Extreme caution should be observed when performing procedures within the cervical spine. If during the procedure the patient experiences severe paresthesia, no matter how perfect the needle position appears to be on fluoroscopy, reposition the needle. There are vascular structures that are
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to be avoided, most notably, the vertebral artery and the cervical radicular arteries (Figure 7.16). The absence of blood aspiration from the needle offers no guarantee that an intravascular injection will not ensue. A prospective study involving 504 cervical transforaminal injections found that observed blood in the needle was 97% specific but only 45.9% sensitive.16 The consequences of intra-arterial injection of particulate material (steroid) are disastrous.17 For these reasons, contrast injection prior to the injection of local anesthetic and steroid is strongly recommended. The patient should be awake enough to converse with the physician, and thus, light sedation is advised (Figure 8.20).18
FIGURE 8.20 Model of the cervical spine.
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FIGURE 8.20 (continued).
C2 Dorsal Root Ganglion Injection The C2 nerve root supplies the C1/C2 joint. Patients with occipital neuralgia may benefit from a C1/C2 intra-articular facet injection, a peripheral occipital nerve block, or a C2 selective nerve root/dorsal root ganglion injection. Patient position: Place the patient in the supine position, with the patient’s head in the neutral position, facing the ceiling. The patient may have to be reminded to maintain this position so that the image seen on the fluoroscopy screen remains constant. C-arm position: 1.
2.
3.
4. 5.
The C-arm is adjusted to obtain a lateral view (Figure 8.7A). Note that the C1/C2 transforaminal injection is the only cervical transforaminal injection that is performed with a lateral image from the C-arm. C2/C3 to C7/T1 transforaminal injections are performed with the oblique view of the C-arm. The C1 ring closely resembles a vertical line if the x-ray beam is projecting in a lateral view and the patient is supine. There should be minimal to no double lines on the upper cervical facets or on the mandible. The facet joints of C2/C3 and C3/C4 should be in focus in this lateral image. The needle depth is ascertained in the P/A view; the needle tip position within the space is determined in the lateral view. The space between C1/C2 is not truly a foramen. The first cervical foramen is located at C2/C3 (Figure 7.14). Tunnel vision describes inserting and guiding the needle in the same direction as the C-arm beam. The needle in this instance appears as little more than a dot on the image. We recommend saving copies of P/A and lateral views showing the needle tip before and after contrast injection.
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Procedure: 1. 2.
Perform sterile preparation and drape to the lateral neck from the hairline to the clavicle. Ensure that the borders are aligned and that the lateral image is truly a lateral image of the patient’s neck. 3. Use the 25-gauge, 2 in. spinal needle to enter the foramen in the lateral view a few millimeters posterior to the AA or C1/C2 joint in the lateral view. The vertebral artery is anterior to the foramen in the lateral view (Figure 7.15, Figure 8.21).
FIGURE 8.21 C2 nerve root injection, lateral view. Note that the needle is posterior to the anterior aspect of the thumb-shaped foramen, but caution is taken not to traverse the vertebral artery.
4. 5.
Note that a tunnel vision view may be used. See that in the P/A view, the needle is lateral to the intersection of the middle and lateral one third of the AA joint (Figure 8.22).
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FIGURE 8.22 C2 nerve root injection, A/P view. The needle is seen no more medial than the lateral one-third of the AA joint.
6.
At this time, connect the contrast-containing syringe that is attached to connection tubing (an immobile needle) and verify under fluoroscopy that the needle has not changed position. The immobile needle technique is especially important with these injections. It helps to keep the needle in the same position after both contrast and epidural steroid injections occurred. Short connection tubing (approximately 0.3 ml capacity) that connects the injection needle to the syringe is recommended.
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Inject a small amount (we suggest <0.5 ml) of nonionic contrast to verify the correct needle position (Figure 8.23).
FIGURE 8.23 C2 nerve root injection with dye spread along the nerve root.
8. 9. 10. 11.
12.
Disconnect the syringe containing contrast, and attach the syringe containing lidocaine. Verify that the needle position has not changed within the foramen. It is this author’s practice to inject approximately 0.5 ml of lidocaine, after negative aspiration, and wait approximately 30 to 60 sec. If the 30 to 60 sec interval is uneventful, this author then removes the lidocaine-containing syringe and replaces it with the syringe that contains the steroid. The needle position is again verified. During these syringe changes, the connection tubing remains in place. We recommend that 1 ml or less of solution (steroid with or without local anesthetic) be injected after negative aspiration.
C3 to C7 Transforaminal Injections Cervical transforaminal injections below the level of the C1/C2 foramen are performed in the oblique view under fluoroscopy. The term “selective nerve root” injection is somewhat of a misnomer, as there is no way to ensure the absence of epidural spread with these injections. However, it is possible to minimize epidural spread by limiting the volume of local anesthetic and steroid injected to the volume of contrast that does not result in epidural spread. Patient position: Place the patient in the supine position as was described in Chapter 7 (Figure 7.13). Ensure that the patient’s head is in the neutral position with the patient looking up at the ceiling. This is very important, as a rotated cervical spine makes accurate needle placement more difficult. The C-arm should be superior to the patient’s head in line with the patient (Figure 8.14). This allows for easy access to the oblique view of the cervical spine. The fluoroscopy table should allow for easy manipulation of the C-arm from the A/P to the oblique views.
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C-arm positioning: When performing intraspinal injections, it is important to know which nerve root is exiting out of the foramen through which the physician plans to inject medications. In the cervical spine, the exiting nerve root is named after the inferior vertebral body; a disc herniation also affects the nerve root at the same level. Thus, the C4 nerve root exits the C3/C4 foramen, and a disc herniation at C3/C4 will also cause most of the symptoms in the distribution of the C4 nerve root. There are a few options for C-arm positioning for transforaminal injections. The steps described below are for procedures performed in the oblique view of the C-arm. This description presumes that the patient is in the supine position. 1. 2.
3. 4. 5.
6.
The patient’s head is aligned with the C-arm, and the C-arm is positioned directly behind the patient’s head. The first step in aligning the C-arm to the patient’s cervical column is to square off the vertebral end plates in the P/A view. This is accomplished by rotating the image intensifier of the C-arm approximately 20˚ forward toward the feet in the P/A view. Next, tilt the C-arm approximately 45˚ in the oblique view until the foramen comes into view. The image intensifier in the final position is relatively close to the patient’s chest (Figure 7.13). Optimize the view of the circular foramen. The contralateral transverse is seen as a circular shadow at the anterior aspect of the vertebral body. Note that the most cephalad foramen seen in the oblique view is always the C2/C3 foramen, through which the C3 nerve root exits. These procedures are best performed on a specialized fluoroscopy table for pain procedures. In some instances, it may improve visualization of the foramen if the patient is moved closer to the pain physician on the procedure bed. The angle needed for the upper cervical foramen is often not the same as it is for the lower cervical foramen due to the natural curvature of the cervical space and the difference in the angulation of the foramen. We recommend saving copies of P/A and oblique views showing the needle tip before and after dye injection.
Procedure: 1. 2. 3.
Sterile preparation and drape of the lateral neck. The needle entry is in the oblique view, at, approximately, a 45˚ angle. The needle is advanced judiciously in the oblique view, verifying the needle depth periodically with a P/A view. It is better to start off with the needle tip a little too anterior and aim the needle posteriorly than to start off a little too posterior in direction and have the needle deflected off the bone and end up too anteriorly. The vertebral artery lies in the anterior aspect of the foramen and is to be avoided (Figure 8.24).
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FIGURE 8.24 The marker shows the target site for the needle in the posterior superior aspect of the foramen.
4.
Check the needle depth in the P/A view (Figure 8.25).
FIGURE 8.25 The needle is approaching the foramen, and this P/A image shows that the needle is still some distance away. The needle depth is too shallow.
204 5.
Handbook of C-Arm Fluoroscopy-Guided Spinal Injections Note that when you check the needle depth with the P/A view, the angle of the C-arm should be noted so that you return to the same image to continue advancing the needle. If the angle increased, then the image seen is more posterior in the foramen (Figure 8.26).
(A)
(B) FIGURE 8.26 (A) The needle is placed in the foramen and the angle of the C-arm adjusted. This needle was placed with the C-arm in the 45-degree oblique view, with the vertebral bodies first squared off in a 20-degree tilt. (B) The needle has not been moved, but the angle of the C-arm has been moved to 55 degrees.
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7. 8.
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The direction of the needle should be established while the needle is relatively superficial. Once tunnel vision or the desired direction is established, the needle may then be advanced to the target spot. It is more likely that the needle will align in the desired direction if the bevel is pointed in the direction of the target on skin entry. It is more desirable to insert the needle at an angle that is directed slightly posterior, thus helping to avoid anterior placement of the needle tip in its final position. The appearance of the needle tip should vary little during the oblique approach. We recommend staying in the posterior and superior aspect of the foramen. When checking the depth of the needle in the P/A view, ensure that the view is indeed an A/P view and not slightly oblique, as it is imperative to know where the needle tip is in relation to the vertebral column. Verify that the spinal processes are lined up in a straight line (Figure 8.27).
(A) FIGURE 8.27 (A) This image is properly aligned; the spinous processes are facing forward. The vertebral endplates are also squared off.
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(B) FIGURE 8.27 (continued). (B) This image is off center, and needle depth cannot be adequately determined.
9.
10.
In most instances, the vertebral artery enters the cervical foramen at C6/C7. Avoidance of injection of particulate material (e.g., steroid) into this artery is critical to avoiding a disastrous neurological outcome. The artery is in the anteromedial aspect of the foramen. The nerve root exits via the distal aspect of the foramen. Thus, the desired needle position is as close to tunnel vision as possible in the postero-lateral aspect of the foramen. In addition, the needle should not venture medial to the halfway point of the facetal column on the P/A view (Figure 8.25). As with the C1/C2 transforaminal injections, it has been this author’s practice to give a “test dose” with lidocaine prior to injection of the steroid: a. Shortly after an uneventful injection of a small amount of nonionic contrast (e.g., 0.5 ml) showing spread along the nerve root into the epidural space and not into the intravascular space, we recommend aspirating again and injecting approximately 0.5 ml of lidocaine without epinephrine (Figure 8.28). This author then waits approximately 30 to 60 sec to avoid intravascular or intrathecal injection. If there is no evidence of either form of undesirable injection, the steroid with or without additional local anesthetic is then injected after repeat negative aspiration, making sure to keep the needle tip in the same position that it was in when the contrast was injected.
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(A)
(B) FIGURE 8.28 (A) The needle is at the midpoint of the facetal column. This is the most medial that the needle should be placed. (B) A small amount of contrast is injected after negative aspiration. A repeat image should look identical to the original image.
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(C) FIGURE 8.28 (continued). (C) This is how the image may appear after the test dose of a short-acting local anesthetic has been administered following adequate contrast spread.
11.
b. The needle is kept immobile with connection tubing joining the needle and syringe with solution to minimize needle movement after contrast confirmation takes place. c. The syringe is aspirated periodically during the insertion of the solution. We recommend obtaining a second fluoroscopic image shortly after contrast is injected to observe that the contrast remained in place. If the needle and contrast are intravascular, the contrast will disappear; the contrast disappears more quickly with intra-arterial vs. intravenous injection. Vertebral artery spread is easily visualized as a quick vertical spread of contrast, which then disappears shortly after injection; radicular artery spread results in a more horizontal spread if the injected contrast. We recommend that consideration be given to cancellation of the procedure of arterial spread of dye is visualized (Figure 8.29).
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FIGURE 8.29 Examples of an intravascular injection.
12.
We recommend saving images of the needle taken in two views with and without contrast, e.g., P/A and oblique, as a record of the procedure.
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Selective Nerve Root Injection or Epidural Steroid Injection There are times when a selective nerve root injection is performed to try to isolate the level of symptoms in the patient. A selective nerve root injection attempts to inject local anesthetic (with or without steroids) just along the nerve root without involving the epidural space. It is very difficult to ensure that the solultion will not traverse into the epidural space. For selective nerve root injections, the needle tip is placed in the more lateral aspect of the foramen (Figure 8.30).
FIGURE 8.30 The needle tip is laterally placed within the foramen to avoid epidural spread.
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A small amount of contrast is injected, and if it spreads along the nerve root and not into the epidural space, the injection is ceased, and the volume injected is noted. The same quantity of local anesthetic is then injected for a “selective” nerve root injection (Figure 8.31 to 8.33).
FIGURE 8.31 A small amount of contrast is injected.
FIGURE 8.32 This is the appearance after the local anesthetic is injected and the nerve root is seen outlined by the washout of the dye.
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FIGURE 8.33 Oblique view of a nerve root injection. There is no detectable epidural spread.
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FIGURE 8.34 Oblique views of a transforaminal injection revealing epidural spread.
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FIGURE 8.34 (continued) A/P views of contrast with epidural spread.
It is important not to confuse selective nerve root injections with intramuscular injections (Figure 8.35).
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FIGURE 8.35 Intramuscular injection and contrast spread.
Figure 8.36 shows an example where the needle was initially placed too laterally with respect to the vertebral border — the injected contrast did not spread into the foramen. The needle was then repositioned, and appropriate contrast spread was seen.
FIGURE 8.36 The initial needle placement in this image was outside the foramen as shown by the lateral contrast spread above the needle. The needle was then repositioned, and contrast is seen spreading along the foramen into the epidural space.
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Interlaminar Epidural Steroid Injections Prior to the routine use of fluoroscopy for cervical interlaminar epidural injections, these injections were traditionally performed in the sitting position with the patient’s head flexed. This sitting technique may also be used when the injections are performed under fluoroscopy with the C-arm encircling the patient. Today, interlaminar injections that are performed under fluoroscopy are generally performed in the prone position with the neck slightly flexed. We recommend that the interlaminar approach be limited to the C7/T1 interspace and below, as work with cadaver specimens indicated that there is minimal posterior epidural space above the C7/T1 interspace.19 Examination of human cadavers revealed midline gaps in the ligamentum flavum at the cervical and thoracic levels. These gaps were frequently observed at the cervical (>50%) levels but were rare below the T3/T4 level.20 Thus, a slightly paramedian approach may be more optimal.19 The solution may then be delivered via the epidural needle or via a catheter threaded through the epidural needle. (This latter technique attempts to mimic the selectivity of a cervical transforaminal injection.) Patient preparation: We recommend obtaining a cervical MRI demonstrating the absence of cervical stenosis at the level of injection. Refer to the beginning of this chapter for other aspects of patient preparation for cervical procedures. Equipment/Materials: We recommend a prepackaged interlaminar epidural kit containing a loss of resistance glass or plastic syringe and a blunt-tipped curved epidural needle, generally 17 or 18 gauge, with or without a radio-opaque catheter. The other materials are the same as for other cervical injections.
Patient position: The patient is placed prone on the procedure table. The patient’s head is placed in a neutral, slightly flexed position facing the floor. C-arm position: The C-arm is adjusted to the patient for an A/P image (Figure 8.8B). The image intensifier is rotated slightly toward the feet to obtain an optimal view of the epidural space. Procedure: 1.
The patient’s posterior neck and upper back are prepared and draped in a sterile fashion. The skin is infiltrated with lidocaine at the C7/T1 interspace. This interspace is generally prominent and easily palpated and then verified with fluoroscopy. 2. The epidural needle is then advanced into the ligamentum flavum in the A/P view. Due to obstruction of the lateral view by the patient’s shoulders, it is very important to be able to detect the sensation of the ligamentum flavum with the epidural needle. Contacting the lamina prior to advancing the needle into the ligamentum flavum is often helpful in assessing needle depth. 3. Loss of resistance with air or saline or a combination is performed. A small amount of nonionic contrast (we recommend approximately 1 ml) is injected after negative aspiration to confirm needle placement in the epidural space. This can be done via the epidural needle or via an epidural catheter. We recommend checking both A/P and lateral views to verify appropriate contract spread (Figure 8.37, Figure 8.38).
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FIGURE 8.37 Interlaminar needle placement with a catheter threaded and contrast lateralized to the left side. The needle was inserted at the C7/T1 interspace.
FIGURE 8.38 Lateral view of interlaminar needle placement at C7/T1. Visualization is often difficult due to opacification by the shoulders. However, you can see that the needle is not anterior to the epidural space.
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4.
We recommend that a low volume of a solution containing, for example, 1 ml of steroid and 2 ml of local anesthetic be injected after a repeated negative aspiration. The steroid-containing solution is then flushed with a small amount of local anesthetic or saline prior to withdrawal of the needle. 5. Once again, we recommend keeping a copy of images in two views, e.g., A/P and lateral views: one with the needle tip without contrast and another with contrast spread. Sometimes contrast may be injected, and it is clear that the needle tip is not in the epidural space. In that case, save the image of the needle tip prior to the last contrast injection and try to have the needle tip visible in addition to having an image with the correct contrast spread within the epidural space. Lateral images may be difficult to visualize due to the shoulder shadow obscuring an optimal view.
Bibliography 1. Horlocker, T.T., Benzon, H.T., Brown, D.L., Enneking, F.K., Helt, B.A., Mulroy, M., Rosenquist, R., Rowlingson, J.C., Tryba, M., Wedel, D., and Yuan, C.-S., Regional anesthesia in the anticoagulated patient: defining the risks (the second ASRA conference on neuraxial anesthesia and anticoagulation), Regional Anesthesia and Pain Medicine, 28(3), 172–197, 2003. 2. Schaerer, J., Radiofrequency facet denervation in the treatment of persistent headache associated with chronic neck pain, Journal of Neurology and Orthopaedic Surgery, 1, 127–130, 1980. 3. Barnsley, L. and Bogduk, N., Medial branch blocks are specific for the diagnosis of cervical zygapophyseal joint pain, Regional Anesthesia, 18, 343–350, 1993. 4. Lord, S.M., Barnsley, L., Wallis, B.J., and Bogduk, N., Chronic cervical zygapophysial joint pain after whiplash. A placebo-controlled prevalence study, Spine, 21, 1737–1745, 1996. 5. Aprill, C. and Bogduk, N., The prevalence of cervical zogapophysial joint pain, Spine, 17, 744–747, 1992. 6. Heldebrandt, J., Percutaneous nerve block of the cervical facets — a relatively new method in the treatment of chronic headache and neck pain, Manual Med, 2, 48–52, 1986. 7. Sjaastad, O., Saunte, C., Howdahl, H., Breivik, H., and Gronbaek, E., Cervicogenic headache. An hypothesis, Caphalgia, 3, 249–256, 1983. 8. Sluijter, M.E. and Mehta, M., Treatment of chronic back and neck pain by percutaneous thermal lesions, in Persistent Pain, Modern Methods of Treatment, Vol. 3, Lipton, S. and Miles, J., Eds., Academic Press, London, 1981, pp. 141–179. 9. Aprill, C., Dwyer, S., and Bogduk, N., Cervical zygapophysial joint pain patterns II: a clinical evaluation, Spine, 15, 458–461, 1990. 10. Lord, S.M., Barnsley, L., Wallis, B.J. et al., Percutaneous radio-frequency neurotomy for chronic cervical zygopophyseal joint pain, New England Journal of Medicine, 335, 1721–1726, 1996. 11. Sluijter, M. and Racz, G., Technical aspects of radiofrequency, Pain Practice, 2, 195–200, 2002. 12. van Kleef, M. and van Suijlekom, J.A., Treatment of chronic cervical pain, brachialgia, and cervicogenic headache by means of radiofrequency procedures, Pain Practice, 2, 214–223, 2002. 13. Lord, S.M., Barnsley, L., and Bogduk, N., The utility of comparative local anesthetic blocks versus placebo-controlled blocks for the diagnosis of cervical zygapophysial joint pain, The Clinical Journal of Pain, 11, 208–213, 1995. 14. Bogduk, N. and Marsland, A., The cervical zygopophyseal joints as a source of neck pain, Spine, 13, 610–617, 1988. 15. Bogduk, N., International Spinal Injection Society guidelines for the performance of spinal injection procedures. Part I: zygapophysial joint blocks, The Clinical Journal of Pain, 13, 285–302, 1997. 16. Furman, M.B., Giovanniello, M.T., and O’Brien, E.M., Incidence of intravascular penetration in transforaminal cervical epidural steroid injections, Spine, 28, 21–25, 2003. 17. Tiso, R.L., Cutler, T., Catania, J.A., and Whalen, K., Adverse central nervous system sequelae after selective transforaminal block: the role of corticosteroids, The Spine Journal, 4, 468–474, 2004.
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18. Rosenkranz, M., Grzyska, U., Niesen, W., Fuchs, K., Schummer, W., Weiller, C., and Rother, J., Anterior spinal artery syndrome following periradicular cervical nerve root therapy, Journal of Neurology, 251, 229–231, 2004. 19. Hogan, Q.H., Epidural anatomy examined by cryomicrotome section. Influence of age, vertebral level, and disease, Regional Anesthesia, 21(5), 395–406. 20. Link, P., Kolbitsch, C., Putz, G., Colvin, J., Colvin, H.P., Lorenz, I., Keller, C., Kirchmair, L., Rieder, J., and Moriggi, B., Cervical and high thoracic ligamentum flavum frequently fails to fuse in the midline, Anesthesiology, 99, 1387–1390, 2003. 21. Niemisto, L., Kalso, E., Malmivaara, A., Seitsalo, S., and Hurri, H., Radiofrequency denervation for neck and back pain: a systematic review within the framework of the Cochrane Collaboration Back Review Group, Spine, 28, 1877–1888, 2003. 22. Cote, P., Cassidy, J.D., Carroll, L.J., and Kristman, V., The annual incidence and course of neck pain in the general population: a population-based cohort study, Pain, 112, 267–273, 2004. 23. Manchikanti, L., Boswell, M.V., Singh, V., Pampati, V., Damron, K.S., and Beyer, C.D., Prevalence of facet joint pain in chronic spinal pain of cervical, thoracic, and lumbar regions, BMC Musculoskeletal Disorders, 5, 15–21, 2004. 24. Seffinger, M.A., Najm, W.I., Mishra, S.I., Adams, A., Dicerson, V.M., Murphy, L.S., and Reinsch, S., Reliability of spinal palpation for diagnosis of back and neck pain. A systematic review, Spine, 29, E413–E425, 2004. 25. Bogduk, N. and Aprill, C., On the nature of neck pain, discography and cervical zygapophysial joint blocks, Pain, 54, 213–217, 1993. 26. Vervest, A. and Stolker, R., The treatment of cervical pain syndromes with radiofrequency procedures, Pain Clinic, 4, 103–112, 1991. 27. Edmeans, J., The cervical spine and headache, Neurology, 38, 1874–1878, 1998. 28. McDonald, Greg J., Lord, Susan M., and Bogduk, Nikolai, Long-term follow-up of patients treated with cervical radiofrequency neurotomy for chronic neck pain, Neurosurgery, 45, 61–67, 1999. 29. Sluijter, M.E., The medial branch procedure, in Radiofrequency Part 2: Thoracic and Cervical Region, Headache and Facial Pain, Sluijter, M.E., Ed., FlivoPress S.A., Meggen (LU), Switzerland, 2003, pp. 99–110. 30. Manelfe, Claude, Ed., Imaging of the Spine and Spinal Cord, Raven Press, New York, 1989. 31. Sherman, J.L., Nassaux, P.Y., and Citrin, C.M., Measurements of the normal cervical spine spinal cord on MR imaging, American Journal of Neuroradiology, 11(2), March–April, 369–372, 1990.
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Chapter
Fluoroscopic Images of the Sacrum and Pelvis
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Posterior View of the Pelvis and the Sacrum Spinal injections that are performed in the sacral and pelvic area (Figure 9.1) may include sacroiliac joint injection, lumbar L5 medial branch block (MBB) and radiofrequency (RF) ablation, and caudal epidural steroid injection. L5 MBB and RF
Sacroiliac joint injection
Caudal epidural steroid injection FIGURE 9.1 Several spinal injections in the sacral and pelvic areas, posterior view of the pelvis and the sacrum.
The sacrum is shaped like a shovel, with the apex, the most inferior portion. An anterior–posterior (A/P) fluoroscopic image of the sacrum is shown in Figure 9.2. The anterior sacral foramina do not align with the posterior foramina because of the curvature of the sacrum.
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A/P View of Fluoroscopic Image of the Sacrum
A Anterior sacral foramina
B
Posterior sacral foramina
C
Posterior sacral foramen
Anterior sacral foramen
D FIGURE 9.2 (A) The spine is in the prone position. The fluoroscopic beam is perpendicular to the table. (B) Photograph of a sacrum from the anterior aspect. (C) The fluoroscopic beam does not align with the anterior and posterior foramina. (D) A/P fluoroscopic image of the sacrum.
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If the x-ray beam aligns the anterior and posterior sacral foramina, we can get an A/P fluoroscopic image like that shown in Figure 9.3D.
Anterior sacral foramina
Posterior sacral foramina A
C
B
D FIGURE 9.3 (A,B) The spine is in the prone position. The fluoroscopic beam aligns the anterior and posterior sacral foramina. (C) A photograph of a sacrum from the anterior aspect. The anterior and posterior foramina align. (D) A/P fluoroscopic image of the sacrum with alignment of the anterior and the posterior foramina.
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Sometimes, changing a fluoroscopic image to a regular x-ray image may help to identify sacral foramina and the sacral hiatus (Figure 9.4). However, sacral foramina and sacral hiatus usually are not easily identifiable due to the air in the rectum and the colon (Figure 9.5).
B A
FIGURE 9.4 Fluoroscopic and x-ray images.
FIGURE 9.5 A/P view of the sacrum. It is difficult to identify the sacral foramina.
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Identifying the posterior superior iliac spine (PSIS) (Figure 9.6) is also important for some spinal injections, such as sacroiliac joint injection, because the needle is inserted below the PSIS. Posterior superior iliac spine
B Posterior and inferior portion of the sacroiliac joint A FIGURE 9.6 (A) A/P fluoroscopic image of the sacrum. (B) A/P photographic image of the sacrum.
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The sacral hiatus is an inferior opening of the spinal canal at the posterior aspect of the sacrum (Figure 9.7A). The shape of the sacral hiatus is an inverted “U”. The two ends of the “U” are called the sacral cornu (Figure 9.7A). Identifying sacral cornu on a lateral fluoroscopic image of the sacrum may aid in performing the caudal epidural steroid injection (ESI) (Figure 9.7D).
B
Sacral hiatus Sacral cornu
A
D
Sacral hiatus C Sacral cornu FIGURE 9.7 (A) Photograph of a sacrum from the posterior aspect. (B) Photograph of a sacrum from the lateral aspect. (C) A/P fluoroscopic image of the sacrum. (D) Lateral fluoroscopic image of the sacrum.
Bibliography Bontrager, K.L. and Anthony, B.T., Eds., Textbook of Radiographic Positioning and Related Anatomy, 2nd ed., C.V. Mosby Company, St. Louis, MO, 1990. Brown, D.L., Ed., Atlas of Regional Anesthesia, 2nd ed., W.B. Saunders, Philadelphia, 1999. Clemente, G.D., Ed., Gray’s Anatomy, 13th ed., Lea & Febiger, Philadelphia, 1984. Fenton, D.S. and Czervionke, L.F., Eds., Image-Guided Spine Intervention, W.B. Saunders, Philadelphia, 2003. Netter, F.H., Ed., Atlas of Human Anatomy, Ciba Geigy Corporation, 1989. Waldman, S.D., Ed., Atlas of Interventional Pain Management, 2nd ed., W.B. Saunders, Philadelphia, 2004.
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Sacroiliac Joint Injection Indications: Low back pain without radiculopathy Contraindications: Patient refusal Systemic anticoagulation or coagulopathy Systemic or localized infection at the site
Step 1: Identify the Target Area The needle is inserted into the posterior–inferior opening of the sacroiliac joint below the posterior superior iliac spine (PSIS) (Figure 10.1). The path of needle insertion has to follow the angle of the posterior opening of the sacroiliac joint. Figure 10.2 is a photograph of the sacroiliac joint on the right side as seen from the posterior aspect. The sacroiliac joint opens medially obliquely backward at an angle, but the angle may vary from patient to patient. Figure 10.3 illustrates different angles of the articular surface for the sacroiliac joint on the sacrum. These different angles create variations for needle placement at the posterior opening of the sacroiliac joint (Figure 10.4). Awareness of these differences is important, because the direction of needle insertion for the sacroiliac joint injection has to be aligned with these angles.
PSIS
FIGURE 10.1 Needle is inserted below the posterior superior iliac spine (PSIS).
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Illustration of the medial– oblique angle of the posterior opening of the sacroiliac joint FIGURE 10.2 Photograph of the posterior opening of the right sacroiliac joint.
FIGURE 10.3 Different angles of the articular surface on the sacrum for the sacroiliac joint.
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FIGURE 10.4 Different angles of the posterior opening of the sacroiliac joint.
Step 2: Position the Patient The patient is in the prone position.
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Step 3: Use C-Arm to Identify the Target Area The C-arm fluoroscopy comes in from the patient’s side (Figure 10.5A). The tunnel vision of the posterior opening of the sacroiliac joint, the right-side sacroiliac joint, and the C-arm should be tilted caudally (Figure 10.5B) and rotated to the patient’s left side (Figure 10.5C). The posterior opening of the sacroiliac joint below the PSIS is identified in Figure 10.6. These figures illustrate the tilting and rotating of the C-arm to get tunnel vision of the posterior opening of the sacroiliac joint.
A
B
C
FIGURE 10.5 C-arm positions for right-sided sacroiliac joint injection.
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PSIS
PSIS
A Posterior opening of sacroiliac joint
PSIS
PSIS Posterior opening of sacroiliac joint
Posterior opening of sacroiliac joint
FIGURE 10.6 Demonstration of how to align posterior opening of the sacroiliac joint.
Step 4 and Step 5: Insert the Needle and Confirm the Needle Placement Proper needle insertion is shown in Figure 10.7. The needle should be inserted right below the PSIS (Figure 10.7A and Figure 10.7B). Using an image of the anterior–posterior (A/P) view of the sacrum (Figure 10.7E) helps not only to check needle depth but also to reconfirm proper needle placement. The needle tip should be inserted below the PSIS and beyond the posterior margin of the posterior joint opening (Figure 10.7D and Figure 10.7E). Contrast solution should spread laterally to the needle tip, indicating correct needle placement (Figure 10.7C and Figure 10.7F).
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D
A
BB
E
C
F
FIGURE 10.7 Proper needle placement.
If the needle is inserted too low (Figure 10.8B and Figure 10.8E), the contrast solution can leak out inferiorly (Figure 10.8C and Figure 10.8F). The patient may have lower extremity weakness on the injected side after receiving local anesthetic, because the medication spreads to the sciatic nerve that is located inferiorly to the lower portion of the sacroiliac joint.
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A
D
B
E
C
F
FIGURE 10.8 Improper needle placement. The needle is inserted too low.
Step 6: Inject Medications We will not discuss the details in this handbook.
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Caudal Epidural Steroid Injection Indications: Lumbar radiculopathy Spinal stenosis Contraindications: Patient refusal Systemic anticoagulation or coagulopathy Systemic or localized infection at the site
Step 1: Identify the Target Area Needle placement for caudal epidural steroid injection is through the sacral hiatus into the sacral epidural space (Figure 10.9).
FIGURE 10.9 Illustration of needle travel via the sacral hiatus.
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Step 2: Position the Patient The patient is in the prone position. The patient should have his or her legs abducted to about a 20° angle, with the toes rotated inward and the heels outward to relax the gluteal muscles (Figure 10.10).
FIGURE 10.10
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Step 3: Use C-Arm to Identify the Target Areas Sometimes it is difficult to identify the sacral hiatus by using the A/P fluoroscopic images because of anatomic variants of the dorsal wall of the sacrum (Figure 10.11) and air in the rectum and colon (Figure 10.10). We recommend also using a lateral view of the sacrum to help identify the sacral hiatus (Figure 10.11C).
B
C
D
E
FIGURE 10.11 (A) Photograph of the normal dorsal wall of the sacrum. (B) Normal dorsal wall of the sacrum with the normal invert U or V sacral hiatus. (C) Small slit-like sacral hiatus. (D) Large sacral hiatus. (E) Large midline defects in the dorsal sacral wall continuous with the sacral hiatus.
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Step 4: Insert the Needle to the Target Area Skin entry should be 2 to 3 cm below the identified point in the sacral hiatus (Figure 10.12). The needle is inserted at an angle of approximately 45° to the sacrum. The needle is then advanced until it contacts the anterior wall of the sacrum between the sacral cornu (Figure 10.13A, Figure 10.14B, and Figure 10.14C). The needle is then withdrawn slightly and redirected at a decreased angle toward the sacral hiatus (Figure 10.13B and Figure 10.14D through Figure 10.14F).
_ _
A
D
B
_
C
_ E
H
_
F
_
I
G FIGURE 10.12 Fluoroscopic A/P images of the sacrum and the sacral hiatus. Arrowheads in A through F may point to the sacral hiatus. It is difficult to identify the sacral hiatus in G through I.
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Sacral cornu
A Sacral hiatus
B
Sacral hiatus
Sacral cornu
C FIGURE 10.13 (A,B) Photographs of the sacrum, lateral view. (C) Lateral view of a fluoroscopic image of the sacrum.
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Sacral cornu
A
B FIGURE 10.14 Needle insertion into the sacral hiatus.
A
D
C
B
E
F
FIGURE 10.15 Fluoroscopic images of the lateral view of the sacrum. (A) Lateral view with the pointer tip. (B) Lateral view with a pointer tip. (C) The needle contacts the anterior wall of the sacrum between the sacral cornu. (D–F) Redirecting the needle.
We found that loss of resistance is not always obtained when the needle enters the caudal epidural space. Therefore, we recommend inserting an epidural catheter frequently while advancing the needle.
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Step 5: Confirm the Needle (Catheter) Placement Proper catheter placement can be confirmed by checking that the catheter follows the curvature of the sacrum (Figure 10.16A) and that the catheter stays at the midline (Figure 10.16B). Final confirmation of proper position of the catheter within the caudal epidural space requires obtaining a caudal epidurogram (Figure 10.16A and Figure 10.16B). The A/P view of the caudal epidurogram shows that spread of the contrast agent looks like a picture of a Christmas tree (Figure 10.17). Epidural catheter
Epidural needle B
A
Epidural catheter
Epidural needle tip
FIGURE 10.16 (A) The lateral view image shows a properly placed epidural needle with a catheter that follows the curvature of the sacrum. (B) The A/P view image shows that the epidural needle tip and epidural catheter stay at the midline.
A
B
C
FIGURE 10.17 (A) Fluoroscopic lateral image of the caudal epidurogram. (B) Fluoroscopic A/P image of the caudal epidurogram. (C) Photograph of the sacrum with sacral nerve, anterior aspect.
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If the catheter is off the midline from the needle tip (Figure 10.18A), a lateral view is required before the contrast agent is given. The catheter tip is usually off the dorsal wall of the sacrum on the lateral view (Figure 10.18B). If the contrast agent is spread only on the one side (Figure 10.18C), the lateral image usually indicates that the catheter is advanced subcutaneously (Figure 10.18D).
A
B
C
D
FIGURE 10.18 Demonstrates a catheter inserted subcutaneously. These images have a diagram of a subcutaneous catheter penciled in. (A) An A/P fluoroscopic image of the sacrum demonstrates the catheter was located laterally to the midline. (B) A lateral fluoroscopic image of the sacrum demonstrates the catheter was not in the caudal epidural space. (C, A/P view) and (D, lateral view) demonstrate a contrast material spreading subcutaneously.
Step 6: Inject Medications We recommend that the total volume of injection be 10 ml, including 5 ml of a local anesthetic, such as 0.25% bupivacaine and 40 mg to a maximum of 80 mg of steroid diluted with normal saline.
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Bibliography Bontrager, K.L. and Anthony, B.T., Eds., Textbook of Radiographic Positioning and Related Anatomy, 2nd ed., C.V. Mosby Company, St. Louis, MO, 1990. Brown, D.L., Ed., Atlas of Regional Anesthesia, 2nd ed., W.B. Saunders, Philadelphia, 1999. Clemente, G.D., Ed., Gray’s Anatomy, 13th ed., Lea & Febiger, Philadelphia, 1984. Fenton, D.S. and Czervionke, L.F., Eds., Image-Guided Spine Intervention, W.B. Saunders, Philadelphia, 2003. Netter, F.H., Ed., Atlas of Human Anatomy, Ciba Geigy Corporation, 1989. Waldman, S.D., Ed., Atlas of Interventional Pain Management, 2nd ed., W.B. Saunders, Philadelphia, 2004.
Chapter
Sympathetic Blocks
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T12
L2
L5
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The sympathetic blocks that we will review include (a) the stellate ganglion block, (b) the lumbar sympathetic block, and (c) the superior gastric plexus block (Figure 11.1). C 1 T12
L2
C 7 T 1 L5
Stellate ganglion block
Lumbar sympathetic block Anterior view of the spine
Superior hypogastric plexus block
L 5
FIGURE 11.1 Sympathetic blocks.
Stellate Ganglion Block (Right Side) Indications: Upper extremity complex regional pain syndrome Phantom limb pain Contraindications: Patient refusal Systemic anticoagulation or coagulopathy Systemic or localized infection at the site
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Step 1: Identify the Target Area The target point is the anterior surface of the transverse process of C7 (Figure 11.2) since the stellate ganglion is located opposite the seventh cervical and first thoracic vertebrae near the head of the first rib. C 1
C1
C6 C7
C 7
T1 The target point Anterior view of cervical spine
T 1
FIGURE 11.2
Step 2: Position the Patient The patient should be in the supine position, and the C-arm can be pushed in from the patient’s head or the side (Figure 11.3 and and Figure 11.4).
FIGURE 11.3 C-arm at patient’s head.
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FIGURE 11.4 C-arm at patient’s side.
Step 3: Use C-Arm to Identify the Target Area Obtain a P/A view of cervical spine and identify the C7 vertebral body and the transverse process (Figure 11.5).
C C7
C C7
C7 transverse process (right side) FIGURE 11.5 A P/A viewed C7–T1 vertebrae.
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Step 4: Insert the Needle Identify the target point on the image (Figure 11.6) and then insert a needle under the C-arm (Figure 11.7).
FIGURE 11.6 A needle tip points to the target point on the image.
FIGURE 11.7 A needle tip contacts the anterior surface of the right-sided transverse process of C7.
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Step 5: Confirm the Needle Placement After obtaining a negative aspiration, inject contrast to confirm the needle placement (Figure 11.8).
FIGURE 11.8 Contrast spreads cephalically and caudally.
Step 6: Inject Medication Inject the recommended medication.
Lumbar Sympathetic Block Indications: Lower extremity complex regional pain syndrome Contraindications: Patient refusal Systemic anticoagulation or coagulopathy Systemic or localized infection at the site
Step 1: Identify the Target Area The target points are the anterolateral surfaces of the lumbar vertebral bodies from L2 to L4 (Figure 11.9). The lumbar sympathetic chain (trunk) lies along the medial margin of the psoas muscles (Figure 11.10).
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T12 T12
L2 L2
L5
L5
Lumbar sympathetic chains (A)
Lumbar sympathetic chains (B)
FIGURE 11.9 (A) Lateral view of the lumbar spine. (B) Anterior view of the lumbar spine.
Psoas muscle
FIGURE 11.10 A/P view of the lumbar spine with psoas muscles.
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The needle is inserted postero–laterally toward the patient’s spine, bypassing the tip of the transverse process (Figure 11.11).
FIGURE 11.11
Step 2: Position the Patient The patient is in the prone position, and the C-arm is pushed in from the patient’s side (Figure 11.12).
FIGURE 11.12 Placement of C-arm at side of prone patient.
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Step 3: Use C-Arm to Identify the Target Area Obtain fluoroscopic images of the low thoracic and upper lumbar regions (Figure 11.13). Identify the tip of the transverse process at the level of L2, L3, or L4 (Figure 11.14). T12
Left
FIGURE 11.13 A/P view of the lumbar spine, including T12.
T12
Left
FIGURE 11.14
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Rotate the C-arm to the injecting side until the tip of the transverse process matches the lateral border of the vertebral body (Figure 11.15).
The tip of the transverse process
FIGURE 11.15
Step 4 and Step 5: Insert the Needle and Confirm the Needle Placement Choose the needle’s entry point (Figure 11.16). Insert and advance the needle under the C-arm fluoroscopy until the needle tip contacts the vertebral body. Then the needle tip is “walked off” the vertebral body (Figure 11.17). The needle depth is checked in the lateral view (Figure 11.18) and in the A/P view (Figure 11.19).
Left
FIGURE 11.16 The tip of the pointer is the needle’s entry point.
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Left
FIGURE 11.17
L3
FIGURE 11.18 Lateral view of the needle placement for the lumbar sympathetic block. The needle tip is slightly posterior to the anterior border of the vertebral body.
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L3
FIGURE 11.19 A/P view of needle placement for the lumbar sympathetic block. The needle tip is located in the center of the pedicle.
Figure 11.20 and Figure 11.21 show spread along the anterior-lateral margin of vertebra in order to confirm the needle placement. If contrast outlines the psoas muscle (Figure 11.22), the needle placement is too lateral to the vertebral body.
FIGURE 11.20
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FIGURE 11.21
Psoas muscles FIGURE 11.22
Step 6: Inject Medication(s) No details will be discussed in this handbook.
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Superior Hypogastric Plexus Block Indications: Chronic pelvic pain Contraindications: Patient refusal Systemic anticoagulation or coagulopathy Systemic or localized infection at the site
Step 1: Indentify the Target Area The target area is the anterior surface of the lower portion of the L5 vertebral body, the disc between L5 and the sacrum, and the anterior surface of the sacral promontory (Figure 11.23 to Figure 11.25).
The target area FIGURE 11.23
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Superior hypogastric plexus L5
L5
A
Superior hypogastric plexus
B
FIGURE 11.24 (A) Anterior view of the superior hypogastric plexus. (B) Lateral view of the superior hypogastric plexus.
Step 2: Position the Patient The patient is in a prone position, and the C-arm is pushed in from the patient’s side (Figure 11.25)
FIGURE 11.25
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Step 3 through Step 6: The needle is inserted from posterior laterally to the spine (Figure 11.26). We prefer not to go through the disc between L5 and the sacrum.
Left
Right
FIGURE 11.26
Get an A/P view of the lower portion of the lumbar spine including L5 and squaring the lower margin of L5 or open the disc space between L5 and the sacrum (Figure 11.27).
L5/S1 disc space is open FIGURE 11.27
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The C-arm is rotated to the injecting side (e.g., to the right; Figure 11.28) until obtaining a large triangle area that is formed by the iliac crest, the lower margin of transverse process, and the lateral margin of the superior articular process of the sacrum.
Target needle entry site FIGURE 11.28
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Insert the needle at the junction between the iliac crest and the superior articular process (Figure 11.29).
Target needle entry site FIGURE 11.29 Initial needle placement for a left-sided superior hypogastric block.
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Advance the needle in the lateral view until the needle tip reaches the anterior margin of L5 (Figure 11.30). Contrast is spread in the A/P view and the lateral view (Figure 11.31). Inject 5 cc of appropriate local anesthetic.
FIGURE 11.30
FIGURE 11.31
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Repeat Step 1 through Step 5 for another side injection. After verifying the needle placement, inject another 5 cc of local anesthetic (Figure 11.32).
(a)
(b)
FIGURE 11.32 A/P view of the needle placement of the right-sided superior hypogastric plexus block (A) without contrast and (B) with contrast.
Bibliography Brown, D.L., Ed., Atlas of Regional Anesthesia, 2nd ed., Saunders, Philadelphia, 1999. Fenton, D.S. and Czervionke, l.F., Eds., Image-Guided Spine Intervention, Saunders, Philadelphia, 2003. Netter, F.H., Ed., Atlas of Human Anatomy,, Ciba Geigy Corporation, Tarrytown, 1989. Walkman, S.D., Ed., Atlas of Interventional Pain Management, 2nd ed., Saunders, Philadelphia, 2004.
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Index A Annulogram, lumbar spinal injection, lateral view, 134–135 Axial skeleton, 8 C-arm rotations, 9 spine, anterior view, 10
B Bones, fluoroscopic view of, 18–26 flat bones patella, 18 rib, 18 irregular lumbar bone facial bones, 19 vertebra, 19 radius, 18 rib on top of patella, 19 short bone, first phalange, 18
C C-arm components of, 32 positioning of, 180, 188, 198, 216 (See also under specific view) C2/C3 to C6/C7 intra-articular joint injection, 180–186 C-arm position, 180 contraindications to, 180 patient position, 180 C2 root injection, 198 A/P view, 200 C-arm position, 198 lateral view, 199 patient position, 198–201 procedure, 199–201 C3 to C7 transforaminal injection, 201–209 C-arm position, 216 C-arm positioning, 202 equipment/materials, 216
patient position, 201, 216 patient preparation, 216 procedure, 202–209, 216–218 Caudal epidural steroid injection, 238–245 contraindications to, 238 dorsal wall, sacrum, 240 fluoroscopic lateral view of, 244 indications, 238 lateral view, 244 epidural needle, 244 sacral hiatus, 241 needle insertion into, 243 needle travel via, 238 sacrum, 241 lateral view, 242 lateral view of, 243 subcutaneous insertion, 245 Cervical epidural injection, 196–218 Cervical facet injection, 172–173 lateral approach, 173 Cervical injection, 169–218 C2/C3 to C6/C7 intra-articular joint injection, 180–186 C-arm position, 180 contraindications to, 180 patient position, 180 C2 dorsal root ganglion injection, 198 C-arm position, 198 patient position, 198–201 procedure, 199–201 C3 to C7 transforaminal injection, 201–209 C-arm positioning, 202, 216 equipment/materials, 216 patient position, 201, 216 patient preparation, 216 procedure, 202–209, 216–218 cervical epidural injection, 196–218 cervical facet injection, 172–173 lateral approach, 173 cervical medial branch injection, 186–191 C-arm position, 188 contraindications to, 188 patient position, 188 cervical transforaminal injection, 196–198 complications of, 180
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interlaminar epidural steroid injection, 216–218 intra-articular facet injection, 174–180 C-arm position, 175 C1/C2 intraarticular injection, patient position for, 175 C1/C2 joint lateral view, 177–178 spine model of, 174 C1/C2 joint injection, 174 C1/C2 joint space, dye within, A/P views, 179 mouth closed, C1/C2 view with, 176 patient position, 175 procedure, 175–179 nerve root injection, 196–218 preparation for, 171 patient preparation, 171 equipment/materials, 171 sedation, 171 radiofrequency denervation, 191–196 C2 dorsal root ganglion injection, 198 C3 to C8 medial branches, 192 C3 to C7 transforaminal injection, 201–209 contraindications, 192 equipment/materials, 192–196 procedure, 192–196 Cervical medial branch injection, 186–191 C-arm position, 188 contraindications to, 188 patient position, 188 Cervical spinal nerve roots, counting of, 166 Cervical spine, 151–167 C-arm positions, 154, 165 cervical spinal nerve roots, counting of, 166 inferior view, 163 injection positions, 153 intervertebral foramina, counting of, 166 lateral view, 158–162 lumbar vertebrae, comparison, 156 model, 197–198 oblique view, 163 P/A view, 157 right-sided obliquely viewed view, 164 superior view, 156 vertebral artery on lateral view of cervical spine, 167 on obliquely viewed cervical spine, 167 Cervical transforaminal injection, 196–198 Circumferential annular tear, lumbar spinal injection, 146 Circumferential collimation. See Iris collimation Classification of bones, 18–26 facial bones, 19 first phalange, 18 flat bones, 18 irregular lumbar bone, 19 long bone, 18 patella, 18 pedicles, 25–26 radius, fluoroscopic view, 18 rib, 18
rib on top of patella, 19 short bone, 18 vertebra, 19 Contrast agent, lumbar spinal injection, improper spread of, 100 Contrast injection within disc space, lumbar spinal, 136–141 Curvature, adult lumbar spine, injection, 113
D Depth of needle placement, lateral view, 51 Discography, lumbar spinal injection, 124–127 A/P view of, 138 mature disc, A/P view, 139 Dye spread within disc, lumbar spinal injection, lateral view, 143
E Epidural steroid injection, 210–215 lumbar transforaminal, 88–111 Equipment/materials, 192–196, 216
F Facial bones, 19 First phalange, 18 Flat bones, 18 patella, 18 rib, 18 Fluoroscopic view of bones, 18–26 Foramen, needle approaching, posterior view, lumbar spinal injection, 89
H High intensity zone, lumbar spinal injection, 125
I Iliac crest, lumbar spinal injection, 120 left oblique view, 121 Injection, spinal, 41–53 axis of C-arm, 47 depth of needle placement, lateral view, 51 fluoroscopic view, 44 initial needle placement, 51
Index levels of vertebral view, 48 location of spine, 43 lumbar spine A/P view, 53 lateral view, 52 prone patient, 48 needle insertion, 43 needle placement, 50 prone position, patient placement, 44 rotation, C-arm, 47, 49 target area identification, 43 Interlaminar epidural steroid injection, 216–218 Interlaminar needle placement with catheter threaded, dye lateralized to left side, 217 Intervertebral foramen, between L5, first sacral segment, insertion of needle into, 112 Intervertebral foramina, counting of, 166 Intra-articular facet injection, 174–180 A/P views of dye within left C1/C2 joint space, 179 C-arm position, 175 C1/C2 intraarticular injection, patient position for, 175 C1/C2 joint dye within, A/P views, 179 lateral view, 177–178 with mouth closed, 176 spine model of, 174 C1/C2 joint, 174 lateral view of C1/C2 joint, with needle approaching joint, 177–178 mouth closed, C1/C2 view with, 176 patient position, 175 procedure, 175–179 spine model of C1/C2 joint, 174 Intraarticular injection performed in patient in prone position, with dye spread along joint space, 186 Intramuscular injection, dye spread, 215 Intravascular injection, 209 Iris collimation, 34 Irregular lumbar bone, 19 facial bones, 19 vertebra, 19
L L3/4, lateral view of contrast within, 140 L5 dorsal ramus injection, 82–84 L4/L5, right side, needle placement between, 110–111 L5 left oblique view, 118 L5 medial branch block, lateral view, needle position recheck, 87 L5 right-sided obliquely viewed, 84 L5/S1 discogram, mature disc at, 146 entry site, 142 epidurogram, left-sided, 125 fluoroscopic beam aligned with, 117
271 lack of alignment, with disc between fluoroscopic beam, 116 lumbar transforaminal epidural steroid injection, 111–124 needle in center of, 145 needle in position for, 144 vertebral end plates squared in AP view, 142 Lamina, 25 Lateral cervical spine labeled with positions of cervical medial branches, 187–188 Lateral view cervical medial branch injection, 190 interlaminar needle placement at C7/T1, 217 Leaf collimation, 33 Left oblique view, initial needle insertion in, 99 Left-sided superior hypogastric block, 265 Levels of vertebral view, 48 Linear collimation. See Leaf collimation Location of spine, 43 Long bone, 18 Longitudinal, circumferential, collimation, 38 Low dose imaging setting application, C-arm control panel, 37 Lower portion, posterior view of, 82 L5/S1, discography at, 141–147 L5/S1 injection, 142–147 Lumbar medial branch block, lateral view, 84 denervation, 87–88 Lumbar spinal injection, 71–147 A/P view, 83 target points on lumbar vertebra in, 77 A/P viewed fluoroscopic view, target points on lumbar vertebra in, 77 annular placement of needle, difficulties with, 132–135 annulogram, lateral view, 134–135 C-arm neutral position, 85 position, 129 circumferential annular tear, 146 contrast agent, improper spread of, 100 contrast injection within disc space, 136–141 curvature, adult lumbar spine, 113 discogram A/P view of, 138 mature disc, A/P view, 139 dye spread within disc, lateral view, 143 equipment/materials, 73 foramen, needle approaching, posterior view, 89 high intensity zone, 125 iliac crest, 120 left oblique view, 121 initial entry point, 88 initial needle placement, 92 intervertebral foramen, between L5, first sacral segment, insertion of needle into, 112 L4, L5, right side, needle placement between, 110–111 L5 left oblique view, 118 right-sided obliquely viewed, 84
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S1, lack of alignment, with disc between fluoroscopic beam, 116 L3/4, lateral view of contrast within, 140 L3/4 disc, lateral view of contrast within, 140 L4/5 disc, lateral view of contrast within, 140 L4/L5, right side, needle placement between, 110–111 L5 medial branch block, lateral view, needle position recheck, 87 L5/S1 discogram, mature disc at, 146 entry site, 142 epidurogram, left-sided, 125 fluoroscopic beam aligned with, 117 lack of alignment, with disc between fluoroscopic beam, 116 lateral view of contrast within, 140 needle in center of, 145 needle in position for, 144 post-procedure, 147 vertebral end plates squared in AP view, 142 left oblique view, initial needle insertion in, 99 left-sided L5/S1 epidurogram, 125 lower portion, posterior view of, 82 lumbar medial branch block, lateral view, 84 lumbar vertebra above L5, right-sided oblique view, 88 manometry syringes, discography, 127 mechanically vs. chemically sensitive discs, 141 medial branch block, 78 needle entering disc, 131–133 needle entry point, oblique view, 122 needle placement, 130–132 lateral view of, 124 needle placements, posterior view, 75 neutral position, C-arm in, 94 nucleus in AP view, needle within, 136–137 oblique view needle placements in, 107 target lumbar vertebra, 129 obliquely viewed fluoroscopic view, 80 over-rotated to right, 98 pain response, of patient, 141 patient position, 128 patient preparation, 73, 127 posterior annular tear, L5/S1 discogram, 147 posterior view, needle in, 95 preparation for needle placement, 127–128 prone position patient, 89 patient in, 75, 112, 128–129 properly rotated vertebrae, 97 right oblique view, needle entry from, 96 right-sided L5 medical branch block, A/P view, 86 right-sided oblique view, lumbar vertebrae, 74 origin of lumbar medial branch in, 74 right-sided obliquely viewed, 79, 81 right-sided obliquely viewed view, 80 S1 superior articular process, needle contacts lateral margin, 123 sedation, 73, 127
steps in, 88–92, 94–124 superior articular process, needle entry lateral to, 130–131 transforaminal epidural steroid injection, 91 left-side L5/S1, needle placement, 122 transverse process, superior articular process, angle between, 103–104 under-rotated lumbar vertebrae, 96 view orientation, 90 Lumbar spine, 55–69 A/P to oblique, 60 A/P view, 53, 57–58, 68 in checking needle depth, 69 lateral view, 52, 63 in checking needle depth, 69 needle depth unchanged, 67 prone position, 63 oblique view, 61 pedicle, 62 prone patient, 48 prone position, 57 right oblique view, 59 Lumbar sympathetic block, 253–260 A/P view, 259 A/P view of lumbar spine, including T12, 256 C-arm at side of prone patient, 255 contraindications to, 253 indications, 253 lumber spine, lateral view of, 254 needle entry point, 257 needle placement, lateral view, 258 psoas muscles, lumbar spine with, A/P view of, 254 Lumbar vertebra above L5, right-sided oblique view, 88
M Manometry, 127–141 Manometry syringes, discography, 127 Marker shows target site for needle in posterior superior aspect of foramen, 203 Mechanically vs. chemically sensitive discs, 141 Medial branch block, 78 lumbar, 73–87 contraindications to, 73 indications, 73
N Needle Needle Needle Needle Needle
at midpoint of facetal column, 207–208 entry site for cervical intraarticular injection, 183 insertion, 43 placement, 50 placements for spinal injection, axial view, 3–4
Index Needle tip laterally placed within foramen to avoid epidural spread, 210 Needles placed in oblique view, 194 Nerve root injection, 210–215 Nucleus in AP view, needle within, 136–137
O Oblique C-arm position for cervical medial branch injection, 189 Oblique view needle placements in, 107 target lumbar vertebra, 129 Oblique view of nerve root injection, 212 Oblique views of transforaminal injection revealing epidural spread, 213–214 Obliquely viewed fluoroscopic view, 80
P P/A view of cervical medical branch injection, 191 P/A view of intraarticular facet injection with dye spread along joint, 185 Pain response, of patient, 141 Patella, 18 rib on top of, 19 Patient in prone position, 182 Patient position, 180, 188, 198–201, 216 Patient preparation, 216 Pedicles, 25–26, 62 Pelvic girdle, 13–17 Pelvis, fluoroscopic view, 221–228 Phalange, first, 18 Posterior annular tear, L5/S1 discogram, 147 Posterior view, needle in, 95 Preparation for, 171 patient preparation, 171 equipment/materials, 171 sedation, 171 Preparation for needle placement, 127–128 Procedure, 192–196, 199–209, 216–218 Prone position lumbar spine, 63 patient in, 75, 89, 112, 128–129 patient placement, 44 Pulse, low dose imaging setting application, C-arm control panel, 37
Q Quantification of radiation exposure, 31–32
273
R Radiation safety, 29–39 C-arm, components of, 32 iris collimation, 34 longitudinal, circumferential, collimation, 38 low dose imaging setting application, C-arm control panel, 37 pulse, low dose imaging setting application, C-arm control panel, 37 quantification, radiation exposure, 31–32 shielding, 39 Radiofrequency denervation, 191–196 C2 dorsal root ganglion injection, 198 C3 to C8 medial branches, 192 C3 to C7 transforaminal injection, 201–209 contraindications, 192 equipment/materials, 192–196 procedure, 192–196 Radiofrequency denervation (C3 to C8) medial branches, 192 Radiofrequency lesion at C7 medial branch, A/P view, 195 Radiofrequency needles approaching cervical facets from lateral view, 193 Radiographic background axial skeleton, 8 C-arm rotations, 9 spine, anterior view, 10 classification of bones, pedicles, 25–26 fluoroscopic view, 18–26 flat bones, patella, 18 irregular lumbar bone, vertebra, 19 radius, 18 rib on top of patella, 19 short bone, first phalange, 18 nerve root injection, 210–215 skeletal anatomy, 13–17 axial skeleton, 13–14 iliac spine lateral view, 17 posterior superior, 17 lumbar vertebra, 15–16 anterior view, 16 lateral view, 15 oblique view, 16 posterior view, 16 superior/oblique view, 15 pelvis, 17 posterior view, 17 sacrum, 17 spine, fluoroscopic view, 10 vertebral column, 5–27 Radius, 18 Rib, 18 on top of patella, 19 Right-sided L5 medical branch block, A/P view, 86 Right-sided oblique view, lumbar vertebrae, 74 origin of lumbar medial branch in, 74
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Right-sided obliquely viewed, 79, 80, 81 Right-sided superior hypogastric plexus block, 267 Rotated view, 47 Rotation of C-arm, 49
S S1 superior articular process, needle contacts lateral margin, 123 Sacral hiatus, needle travel via, 238 Sacroiliac joint injection, 231–237 angles of posterior opening of, 233 articular surface on sacrum for, 232 contraindications to, 231 improper needle placement, 237 indications, 231 needle placement, 236 posterior, needle inserted below, 231 posterior opening of, 235 right, posterior opening of, 232 right-sided injection, C-arm position for, 234 Sacrum, fluoroscopic view, 221–228 A/P view of sacrum, 227, 230 fluoroscopic view, 226 posterior aspect, 228 posterior view, 223 prone position, 224–225 sacrum from posterior aspect, 228 spine in prone position, 224–225 x-ray view, 226 Safety with radiation, 29–39 C-arm, components of, 32 iris collimation, 34 leaf collimation, 33 longitudinal, circumferential, collimation, 38 low dose imaging setting application, C-arm control panel, 37 pulse, low dose imaging setting application, C-arm control panel, 37 quantification, radiation exposure, 31–32 shielding, 39 Sedation, 73, 127 Shielding, 39 Short bone, 18 first phalange, 18 Skeletal anatomy, 13–17 axial skeleton, 13–14 lumbar vertebra, 15–16 anterior view, 16 lateral view, 15 oblique view, 16 posterior view, 16 superior/oblique view, 15 pelvis, 17 lateral view, 17 posterior view, 17
posterior superior iliac spine, 17 sacrum, 17 Small amount of dye injected, 211 Spinal injection, 41–53 axis of C-arm, 47 depth of needle placement, lateral view, 51 fluoroscopic view, 44 initial needle placement, 51 levels of vertebral view, 48 location of spine, 43 lumbar spine A/P view, 53 lateral view, 52 prone patient, 48 needle insertion, 43 needle placement, 50 prone position, patient placement, 44 rotated view, 47 rotation of C-arm, 49 target area identification, 43 Spine, 10 Spinous process, 25 Stellate ganglion block, 250–253 C-arm at patient's head, 250 C-arm at patient's side, 251 contrast spreads, cephalical, caudal, 253 needle tip, 252 P/A viewed C7-T1 vertebrae, 251 right side, 249–253 Steps in, 32–39 Superior articular process, needle entry lateral to, 130–131 Superior hypogastric plexus block, 260–267 anterior view of superior hypogastric plexus, 261 contraindications to, 260 indications, 260 Supine position, C-arm aligned for lateral view, 181 Sympathetic block lumbar, 253–260 A/P view, 259 A/P view of lumbar spine, including T12, 256 C-arm at side of prone patient, 255 contraindications to, 253 indications, 253 lumber spine, lateral view of, 254 needle entry point, 257 needle placement, lateral view, 258 psoas muscles, lumbar spine with, A/P view of, 254 superior hypogastric plexus block, 260–267 contraindications to, 260 indications, 260 Sympathetic blocks, 247–270 left-sided superior hypogastric block, 265 right-sided superior hypogastric plexus block, 267 stellate ganglion block, 250–253 C-arm at patient's head, 250 C-arm at patient's side, 251 contrast spreads, cephalical, caudal, 253
Index needle tip, 252 P/A viewed C7-T1 vertebrae, 251 right side, 249–253 superior hypogastric plexus block, 262–267 anterior view of superior hypogastric plexus, 261
T Target area identification, 43 Transforaminal epidural steroid injection, 91 left-side L5/S1, needle placement, 122 Transverse process, superior articular process, angle between, 103–104
275
U Under-rotated lumbar vertebrae, 96
V Vertebral artery on lateral view of cervical spine, 167 on obliquely viewed cervical spine, 167 Vertebral column, 13–17 pelvic girdle, 13–17 radiographic background of, 5–27