Pocket Atlas of Spine Surgery - Singh, Kern [SRG]

Pocket Pock et Atlas of Spine Surgery

Pocket Atlas of Spine Surgery

Kern Singh, MD Assistant Professor Department of Orthopaedic Surgery Rush University Medical Center Chicago, Illinois Alexander R. Vaccaro, MD, PhD The Everrett J. and Marion Gordon Professor of Orthopaedic Surgery Professor of Neurosurgery Co-Director, Delaware Valley Spinal Cord Injury Center Co-Chief, Spine Surgery Co-Director, Spine Surgery Thomas Jeff erson University The Rothman Institute Philadelphia, Pennsylvania

Thieme Medical Publishers, Inc. 333 Seventh Ave. New York, NY 10001 Executive Editor: Kay Conerly Editorial Assistants: Daniel de Corral Editorial Director, Clinical Reference: Michael Wachinger Production Editor: Kenneth L. Chumbley Medical Illustrator: Andrew Evansen International Production Director: Andreas Schabert Senior Vice President, International Marketing and Sales: Cornelia Schulze Vice President, Finance and Accounts: Sarah Vanderbilt President: Brian D. Scanlan Compositor: Prairie Papers Inc. Printer: Asia Paci fic Off set Library of Congress Cataloging-in-Publication Data Singh, Kern. Pocket atlas of spine surgery / Kern Singh, Alexander R. Vaccaro. p. ; cm. ISBN 978-1-60406-308-0 (alk. paper) I. Vaccaro, Alexander R. II. Title. [DNLM: 1. Spine—surgery—Atlases. 2. Spine—surgery—Handbooks. WE 17] 617.471--dc23 2011040811 Copyright © 2012 by Thieme Medical Publishers, Inc. This book, including all parts thereof, is legally protected by copyright. Any use, exploitation, or commercialization outside the narrow limits set by copyright legislation without the publisher’s consent is illegal and liable to prosecution. This applies in particular to photostat reproduction, copying, mimeographing or duplication of any kind, translating, preparation of micro films, and electronic data processing and storage. Important note: Medical knowledge is ever-changing. As new research and clinical experience broaden our knowledge, changes in treatment and drug therapy may be required. The authors and editors of the material herein have consulted sources believed to be reliable in their eff orts to provide information that is complete and in accord with the standards accepted at the time of publication. However, in view of the possibility of human error by the authors, editors, or publisher of the work herein or changes in medical knowledge, neither the authors, editors, nor publisher, nor any other party who has been involved in the preparation

I dedicate this book to my father. As I now progress into parenthood, I realize the sacrifices you made for me. Never ending patience, bountiful amounts of time, and a dedication to giving me every opportunity to succeed. K. Singh

This book is dedicated to my one and only true hero, my father, Alexander Vaccaro, Senior, who to this day I look to for guidance and wisdom in all aspects of my life. A. Vaccaro

Contents

Foreword .................................................................................................................................ix Preface ......................................................................................................................................xi

I Introduction 1

Cervical Surgical Positioning ......................................................................................... 3

2

Thoracic and Lumbar Surgical Positioning ................................................................ 6

II Cervical 3

Anterior Cervical Diskectomy and Fusion................................................................13

4

Anterior Cervical Corpectomy and Fusion ...............................................................21

5

Open Posterior Cervical Foraminotomy ...................................................................27

6

Minimally Invasive Posterior Cervical Foraminotomy.........................................30

7

Occipitocervical Fusion ..................................................................................................34

8

Posterior Cervical Laminectomy and Fusion ..........................................................41

9

Posterior Cervical Laminaplasty with Instrumentation ......................................46

III

Thoracic Spine

10

Percutaneous Cement Augmentation .......................................................................53

11

Thoracic Pedicle Screw Placement .............................................................................60

viii

Contents

20

Percutaneous Pedicle Screw Placement ................................................................ 113

21

Extreme (eXtreme) Lateral Interbody Fusion ...................................................... 124

22

Minimally Invasive Lumbar Corpectomy .............................................................. 130

23

Anterior Lumbar Interbody Fusion ......................................................................... 134

Foreword

So why would another atlas of spine surgery be needed, one may ask? Well, in this unique, singularly authored (Singh) and edited (Vaccaro) new pocket atlas, one will find the most anatomic-specific, approach-centric, consistent material on a myriad of the most common spinal surgical techniques I have ever seen. The innovative manner of providing a clear anatomic description of the “target spine anantomy,” core to any spinal surgery, within the context of the surrounding anatomy, as well as the layers of dissection required to get there, is absolutely brilliant and highly instructive. It produces a nearly three-dimensional anatomic perspective rarely obtained in a textbook, which is important not only for conventional open surgical techniques, but mini-open, minimally invasive, and percutaneous procedures as well. The atlas is organized anatomically into sections on positioning, cervical, thoracic, and lumbar surgery. Within those sections it covers the most common spinal surgeries with specific and useful text accompanying the wonderful pictures, intraoperative photos, and drawings. I was especially pleased to note a constant focus on proper visualization through adequate hemostasis and precise anatomic relevance to the procedures, as these are two of the most essential principles to successful spine surgery in my experience. The chapters can be covered quickly and reflect on the well laid out combination of labeled illustrations and accompanying text. This atlas avoids having too much irrelevant detail and excessive text to detract from the illustrations, which adds to the optical aesthetics of the material and allows quick and easy learning. The primary audience for this atlas is obviously the young practicing surgeon, along with medical students, residents, and fellows learning spinal surgery. However, with its emphasis (almost 50 percent of the text) on the newer

Preface

Spinal surgery atlases are abundant, and the myriad of options can overwhelm any practicing medical professional. However, these atlases tend to be large and too cumbersome to bring into the operating room. This atlas was created to serve a much diff erent purpose. Aside from its most obvious advantage of being extremely pocket-friendly, several other features make it shine. The illustrations are detailed, providing not only visualization of the operative field using actual, intraoperative, high-definition photographs, but also have beautifully illustrated “see through” adjacent anatomy. The reader is allowed to visualize the entire surgical field, including the anatomy that is never “seen” while operating. This translucent view into complex spinal anatomy helps the reader understand the subtleties of technically demanding techniques such as minimally invasive spinal surgery. This atlas is thorough, providing detailed anatomic photographs and illustrations of the most common surgical techniques, both open and minimally invasive. Each procedure chosen was carefully selected to highlight the most common procedures performed by a practicing spine surgeon. In addition, MIS techniques that are very technically demanding have been incorporated, which allows the surgeon to understand the surrounding nonvisualized anatomy. The artwork allows the reader to become comfortable with the surgery before setting foot in the operating room. The accompanying text not only describes the surgical technique, but also off ers pearls and tips to help perform the procedure expeditiously. Common complications are described, as well as suggestions for their avoidance. This atlas will serve as a valuable resource not only for orthopedic surgeons, neurosurgeons, and surgical trainees such as residents and fellows, but also for

I Introduction

1 Cervical Surgical Positioning ■

Anterior Cervical

foam pad t a p e

doughnut to stabilize head

• The head is placed onto a doughnut to maintain its position. A bump or roll is placed horizontally across the scapulae to allow for gentle extension of the cervical spine. Care should be taken to avoid hyperextension in patients with

4

I Introduction

■

Posterior Cervical

1 Cervical Surgical Positioning

• The table is slightly raised with the head above the feet to allow for venous drainage.

t a p e

5

2 Thoracic and Lumbar Surgical

Positioning ■

Anterior Lumbar

• The patient is positioned with his or her arms across the chest. This allows for the c -arm to be moved cephalad in the field. A lateral c -arm is essential for localization and implant placement.

2 Thoracic and Lumbar Surgical Positioning

bump

• Additionally, the table can be positioned with the head lower than the feet, allowing the abdominal contents to fall away from the operative field. – A bump may be placed under the sacrum to increase lordosis.

7

8

I Introduction

■

Lateral Thoracic/Lumbar

axillary roll

bump

• The patient is positioned on a regular operating room table with a bump underneath the aff ected level. The patient is also positioned with the operative site over the break in the bed, allowing the patient to be maximally flexed at the surgical level.

2 Thoracic and Lumbar Surgical Positioning

bump

• Tape is used to secure the pelvis and the thorax so that flexion can be accomplished without movement of the patient on the operating table. The arms are well padded, and an axillary roll should be placed under the patient to avoid any brachial plexopathies.

9

10

I Introduction

■

Posterior Thoracic/Lumbar

ulnar nerve

• For cases that involve a posterior thoracic and lumbar procedure, the Jackson table is often preferred. The Jackson table is radiolucent and allows for the chest and hip pads to be placed independently. The chest pads should be placed at the level of the manubrium and below the axilla. The hip pads should be placed just below the anterior superior iliac spine (ASIS). The thigh pads are often placed immediately below the hip pad. When the chest and thigh pads are placed this way, it allows the abdomen to hang freely, decreasing venous bleeding during the surgical procedure. The neck is placed into a neutral position, with care being taken to protect the eyes from pressure.

II Cervical

3 Anterior Cervical Diskectomy

and Fusion Tips and Pearls Before You Begin Anatomic landmarks may aid in the placement of the surgical incision. Typically, the hyoid bone overlies the C3 vertebral body, the thyroid cartilage overlies the C4–5 intervertebral disk space, and the cricoid ring overlies the C6 level. Disk space localization is performed with a radiopaque marker and a lateral radiograph. Needles for localization should be placed into the vertebral body and not the disk space to prevent possible disk degeneration in case the wrong level is localized.

hyoid bone

thyroid cartilage

thyroid gland

mandible

sternum

carotid artery vagus nerve

. a r v u l a

sternohyoid m. o m mo o h hy y o i i d o d m . d m o i d t s m a d o i d

.

trachea

14

II Cervical

C6 transverse process thyroid cartilage

C7 transverse process

thyroid gland

st er no hy o o i i d d m.

t r ra c he a

o mo hy o oi i d d m.

carotid sheath

d m. t o i d s a d o m e i d o c l e n r e s t

• A horizontal incision is made just medial to the sternocleidomastoid sternocleidomastoid muscle (SCM). • A decision on a right- or left-side approach should be made based upon surgeon comfort. C6 transverse process thyroid cartilage

st er no hy o o i i d d m.

thyroid gland

t r ra c he a

C7 transverse process

3 Anterior Cervical Diskectomy and Fusion

thyroid cartilage

sternohyoid m.

thyroid gland

C7

t r ac h e a

omohyoid m.

ex te r nal jugular v . carotid sheath m. t o i d s a i d o m o c l e n r e t s

C7

• The SCM and carotid sheath are retracted laterally. – The tracheoesophageal complex is retracted medially. – The recurrent laryngeal nerve lies in the tracheoesophageal groove. – The cartoid sheath contains: the internal jugular vein the cartoid artery the vagus nerve ▫ ▫ ▫

15

16

II Cervical

thyroid gland thyroid cartilage sternohyoid m.

C7 t ra c h e a

omohyoid m.

carotid sheath

ext er nal jugular v . m. t o i d s a o m c l e i d o n r s t e

C7

• The longus colli are swept laterally, exposing the superficial disk space. – The sympathetic chain lies superficial to the longus colli; therefore, retractors should be placed deep into this muscle. • A knife or electrocautery device can be used to perform the annulotomy.

recurrent


r e cu r l ar yn t ge r en a l n .

spi nal c or d C4

C4–C5 disk

C5

post er ior longit udinal lig. vertebral a.

C6

C6–C7 disk

t r ac hea

C7 ascending cervical a.

carotid sheath

vagus a.

nerve roots

• A microcurette or nerve hook, along with a 1 mm Kerrison rongeur, can be used to remove the posterior longitudinal ligament. – A 6–0 angled curette is helpful for getting behind the unciate process.

spinal c or d C4–C5

r ec u r l a r yn t ge r en al n .

t ra c hea

17

18

II Cervical

C4

t ra r e cu ch e r r a e nt l ar y n g ea l n .

C5

ascending cer vi cal a.

C6

C7

vertebral a. carotid sheath

nerve roots

• A trial sizer is placed to approximate the intervertebral space.

r e cu r r e

t ra ch e a


r e cu rr e nt l ar y n g ea l n . C4

C5

C6 C7

vertebral a.

ascending cervical a.

carotid sheath

C4 nerve root

• An anterior cervical plate is applied. – The shortest feasible plate should be used to avoid abutment of the adjacent disk space.

19

20

II Cervical

Potential Pitfalls The incidence of vocal cord paralysis from recurrent laryngeal nerve injury ranges from 1% to 11%. Possible etiologies include traumatic division, neuropraxia, compression from postoperative edema, and injury from thermal necrosis. Midline soft tissue injury to the trachea, esophagus, and pharynx is uncommon. Dysphagia following anterior cervical surgery is common but temporary; it is estimated to occur transiently in 8% of patients. Simple measures to help reduce the incidence of dysphagia include avoiding overzealous retraction of the esophagus, intermittently relaxing self-retaining retractors during the procedure, and partially deflating the endotracheal cuff once the cervical retractors are in position. Vascular injuries may be prevented by avoiding overzealous retraction and by using blunt-edged retractors. The likelihood of pseudarthrosis may be minimized by performing a meticulous diskectomy and a thorough decortication of the end plates.

4 Anterior Cervical Corpectomy and Fusion

Tips and Pearls Before You Begin Obtaining proper imaging studies is paramount for optimal surgical treatment. Careful evaluation of the location and course of the vertebral artery is necessary to avoid iatrogenic injury. At the time of surgery, complete diskectomies before resection of the vertebral bodies facilitate assessment of the depth of the vertebral body as well as the location of the spinal canal. In cases where ossi fication of the posterior longitudinal ligament is extremely adherent to the dura, direct resection can be dangerous. Successful decompression can be performed by removing the posterior longitudinal ligament on either side of the ossified area and allowing it to float away anteriorly from the cord (anterior floating technique) without necessitating direct resection. When a corpectomy is performed, a high-speed burr can be used to resect most of the vertebral body, leaving only a thin rim of posterior cortical bone. The posterior cortical bone can be removed using either a small curette or a Kerrison rongeur.

t ra c he a s te r n oh y o id m .

C4–

22

II Cervical • Before the corpectomy is begun, the disk space above and below the vertebral body to be resected is clearly exposed. • The uncovertebral margin is the most reliable reference in determining the lateral extent of the vertebral body resection. – A Penfield elevator may be used to palpate the transverse process to ensure that lateral dissection is suffi cient. The vertebral artery lies deeper than the plane of dissection (posterior middle third of the vertebral body). ▫

t ra s te r n c he a o h y o i d m .

C4 C6–C7 disk

r e cu r r en l a r yn g ea l t n . S C M

vertebral a.


carotid sheath nerve root

• A Leksell rongeur can be used to remove most of the vertebral body quickly.


t ra s te r n c he a o hy o i d m .

PLL C4

C6–C7 disk

r e cu r r l a r yn ge a e nt l n . S C M


carotid sheath

• A high-speed burr can be used to remove the remaining bone laterally and posteriorly until the posterior longitudinal ligament (PLL) is identified. – In most cases, an adequate decompression can be accomplished while preserving the PLL, which can then serve to prevent overdistraction from the interposed graft. The defect should be widened to the uncovertebral margin to ensure adequate thecal sac decompression. ▫

23

24

II Cervical

s te r n o h y o i d m .

C4

PLL C6 nerve roots

recurrent laryngeal n.

C6–C7 disk S C M


carotid sheath

• Bleeding from the cancellous vertebral body can be controlled with gelfoam or other thrombotic agents.


t ra s te r n c he a o hy o i d m .

r e cu r r e l a r yn g ea ln t n .

C4 C6–C7 disk vertebral a.

S C M


carotid sheath

• The bone graft from the corpectomy site can be placed into and around the cage. – Bone should be saved in non-neoplastic or noninfectious cases. – In cases of malignancy or infection, bone graft substitute should be utilized.

25

26

II Cervical

• The patient suff ered a traumatic C5 burst fracture with neurological deficit. • An AP/lateral radiograph demonstrating C5 corpectomy (PEEK cage) with an anterior cervical plate extending from C4 to C6.

Potential Pitfalls • Iatrogenic injury to the vertebral artery can occur either because of an aberrant vertebral artery or from excessive lateral decompression. • Dural tear, spinal fluid leak, or neurologic injury can occur during resection of the posterior vertebral body and the posterior longitudinal ligament. • Graft extrusion and hardware failure can occur in cases of prior posterior de-

5 Open Posterior Cervical Foraminotomy

Tips and Pearls Before You Begin Intraoperative imaging is mandatory to confirm the correct level of decompression. The use of anatomic landmarks can be helpful in many cases, but normal anatomic variants may lead to confusion and ultimately to surgery on the wrong level. Visualization can be enhanced with an operating microscope or with a combination of loupes and a fiber-optic head light.

spinal cord

C3

C5 spinous process

nerve roots

C6 spinous process

IAP

C7

T1

28

II Cervical

spinal cord

C5 spinous process

C3

C6 spinous process

resected IAP SAP of C6

C7

T1

C5–C6 nerve root

• Approximat Approximately ely 35% of the medial portion of the IAP is removed to visualize the superior articular proces processs (SAP) of the caudal vertebrae.

5 Open Posterior Posterior Cervical Cervical Foraminotomy Foraminotomy

C3

C4

C5

C6

C7

C6 nerve root keyhole foraminotomy

• A keyhole foraminotomy foraminotomy is created with the nerve root visualized.

T1

29

6 Minimally Invasive Posterior Cervical

Foraminotomy

C1 (atlas) C2 (axis) C3

initial dilator

C4 C5

• A lateral fluoroscopic image is used to identify the level in question. • An incision is made 0.5 cm lateral to the midline.

6 Minimally Invasive Posterior Cervical Foraminotomy

C1 (atlas) C2 (axis) C3 C4

tubular dilator

C5

• Tubular dilators (18 mm) are used to spread the paraspinal muscles.

C3

C4

C5

C6

31

32

II Cervical

C3

C4

C5

C6

C5 nerve root

SAP of C5

IAP of C4

• A burr is used to remove the medial third of the inferior articular process (IAP) of the cephalad vertebrae.

C3

C4

C5

C6

6 Minimally Invasive Posterior Cervical Foraminotomy

Potential Pitfalls • Excessive retraction or compression of the neural elements may lead to iatrogenic neurologic symptoms. Persistent postoperative symptoms may be caused by inadequate decompression. • Excessive resection of the facet joint may result in increased neck pain and, possibly, spinal instability.

33

7 Occipitocervical Fusion

Tips and Pearls Before You Begin For dual plating, occipital screws should be placed three to a side on either side of the midline, just below the superior nuchal line and as close to the external occipital protuberance as possible. An independent occipital plate may require only two or three screws, usually oriented in a vertical or transverse orientation. Leakage of cerebrospinal fluid (CSF) at this stage can usually be stopped by placing a screw or bone wax into the hole.

o t r o e r v e n 2 C

ter y ver te bra l ar

occiput C1

dura C2

C3



vertebral artery

occiput

C1

curette into foramen magnum

dura C2

C3

C2 nerve root resected

lateral mass edges

C2 pedicle screw start point

• A curette is placed into the foramen magnum to clearly define the inferior border of the occiput.

r y o t ve r te b ra l a r te o r v e r n e 2 C occiput

35

36

II Cervical


vertebral artery

occiput C1

dura C2

C3


lateral mass edges

C2 pedicle screw start point

• The C2 (axis) pedicle screw starting point occurs at the inferior and lateral edge of the inferior articular process of C2. – The vertebral artery lies directly anterolateral. The screw should be directed medial and cephalad to avoid potential vascular injury. Screws placed bicortically into the anterior axis may risk injury to the internal carotid artery. ▪ The C2 screw is angled 20° medially and 15–20° caudally (use lateral flouroscopy). ▫


y o t a l a r t e r r b e t o r e v r v e r n e 2 C occiput dura C1

C2

C3


screw tract probed

• The screw tract is drilled and then probed to ensure that the cortical walls are not breached.

y o t a l a r t e r r o v e r t e b r e r v e n 2 C

37

38

II Cervical


vertebral artery

occiput dura C1

C2

C3


lateral mass edges

C1 lateral mass screw start point

• The C1 (atlas) lateral mass screw starting point is inferior to the arch of C1. The C2 (occipital) nerve root has been resected to facilitate screw placement. – Resection of the C2 nerve may result in occipital dythesthesias in up to 20% of patients. – The ponticulus posticus (Latin for “little bridge to the rear”) refers to a bony bridge on the atlas that covers the groove for the vertebral artery (also known as the arcuate foramen). It is a common anatomic variant that is estimated to occur in 3% to 15% of the population.


t o o r v e e r n C 2

dura

C2

C1

C3

lateral mass boundary vertebral artery

• C1 lateral mass screw placement is shown. Note that the C2 nerve root has been resected, exposing the C1 lateral mass and C1–C2 facet joint.

o t r o e r v e n C 2

dura

39

40

II Cervical

dura

C1

C2

vertebral artery

• The C1 lateral mass is screw inserted.

Potential Pitfalls Perpendicular occipital screw placement can be especially di ffi cult due to the steep angle required close to the foramen magnum. If the occipital occipital bone close to the foramen magnum is unusually thin or in certain pathologic states, this can make adequate screw purchase difficult or even impossible. Occipital Occipital screw place-

8 Posterior Cervical Laminectomy and Fusion

Tips and Pearls Before You Begin In patients with myeloradiculopathy myeloradiculopathy and significant radicular symptoms, the presence of foraminal stenosis should be identified on preoperative imaging studies and appropriate concomitant foraminotomies planned. During preoperative positioning, excessive flexion or extension should be avoided in myelopa myelopathic thic patients. For foraminotomies, slight flexion opens the interspaces and foramina, but care must be taken during dissection, as the dural sac is more suscep susceptible tible to injury. injur y. The surgical exposure for laminectomy proceeds caudal caudal to cephalad; this facilitates subperiosteal detachment of paraspinal muscles, which attach in the same direction, and reduces bleeding. A clamp is placed on an exposed spinous process, and a lateral radiograph is obtained to confirm levels. Dissection should proceed to the lateral margin of the facet joints. This extent of exposure establishes the landmarks needed for safe placement of lateral l ateral mass screws and ensures that more than half of the facet joint is not removed during any associated foraminotomy. Dissection beyond the lateral margin of the facet joint risks significant bleeding from the soft tissue musculature. Care must be taken to avoid injuring the facet capsules at any level if a fusion is i s not planned.

42

II Cervical

lateral mass boundaries vertebral artery

C3

C4

C6

C5

C7

interspinous ligament

lateral mass boundaries

vertebral artery nerve roots

• A midline posterior approach is utilized, with dissection performed through the avascular ligamentum nuchae. • Subperiosteal exposure is performed, extending out to the lateral edge of the lateral mass. encountered ed along the lateral edge of the lateral mass. – Bleeding is typically encounter – This bleeding can be controlled with bipolar cautery.



C3

C4

C6

C5

C7

starting point

lateral mass boundaries

vertebral artery nerve roots

• The lateral mass is exposed and clearly defined, exposing the superior, inferior, and medial lateral borders.


43

44

II Cervical

screw holes vertebral a.

C6

C4

C3

troughs

C7

vertebral a. nerve roots

• Once the lateral mass screw holes are created, a laminectomy can be performed. – Two troughs are created with a high-speed burr. – The troughs are created just medial to the screw start points at the junction of the lateral mass and lamina.

screw holes vertebral a.


lateral mass screws spinal cord

cross connector

rods

• The lateral mass screws are then placed and rods are secured in place. A cross connector can be applied to increase torsional rigidity. – The bone graft is placed into the decorticated facet joints.

Potential Pitfalls A laminectomy accomplishes indirect decompression of the spinal cord by allow ing posterior translation of the cord away from the anterior compressive pathology. Typically, a minimum of three or four levels is required to allow adequate

45

9 Posterior Cervical Laminaplasty with

Instrumentation Tips and Pearls Before You Begin Incise the nuchal ligament and paracervical muscles at the exact midline, and strip the muscles subperiosteally to avoid bleeding. Be careful not to strip or expose the cervical facet capsules. Complete the hinge side gutter last, after completion of the open side gutter and the resection of the ligamenta flava at both ends of the laminar door. Check the stability of the hinge frequently while making the hinge gutter. Preserve the spinous process of C7 whenever possible to reduce postoperative axial symptoms. Encourage early active range of motion of the neck.

facet capsules

vertebral a.

C3

C4

C5

C6

C7

9 Posterior Cervical Laminaplasty with Instrumentation

facet joint

C5

C6 C7

C4

C3 spinous process removed vertebral artery

nerve roots

• Once exposed, the spinous processes from C3–C7 are removed. facet joint

epidural veins

C3

C4

C5

C6

C7

T1

47

48

II Cervical

epidural veins

C3

C4

C5

C6

C7

T1

vertebral a. dura mater

3 mm trough created at laminar/facet junction nerve roots

• A burr is used to create an opening of approximately 3 mm. • This opening requires the removal of 15% of the facet joint.

9 Posterior Cervical Laminaplasty with Instrumentation

unicortical trough

C3

C4

C5

C6

C7

spinal cord epidural veins

facet joint

nerve roots

• Once the first trough is complete, a similar trough is created on the other side (hinge side). • However, the hinge side trough is only unicortical. unicortical trough acts as “hinge”

C6

lamina opened to decompress spinal cord

49

50

II Cervical

1 screw into lamina; 2 screws into facet

• The plates are secured with 5 mm screws. – Two are fastened into the lateral mass. – One is fastened into the lamina. • The plate secures the lamina in an expanded state, decompressing the spinal cord.

Potential Pitfalls

III Thoracic Spine

10 Percutaneous Cement Augmentation

Tips and Pearls Before You Begin The use of biplanar fluoroscopy greatly aids in cannula insertion and cement injection. The lateral image is brought over the top or under the bed, with the arc leaning away toward the head. The anteroposterior (AP) image is brought in diagonally, with the image intensifier directly over the target site. It is most convenient to obtain the true AP image first, because the diagonal entry makes this process challenging. The lateral image is then adjusted around the AP image. Treatment of multiple levels can be performed with a single batch of cement. The cement is stored in a sterile ice water bath to slow the polymerization process. With vertebroplasty, all the cannulas are inserted first, and then each site is injected sequentially. With kyphoplasty, the first site is drilled, the balloon tamp deployed, and the cement injected. The limit on the number of levels is dictated by the cement load. The risk of cement toxicity increases with the number of levels treated. As a general rule, no more than three levels are treated in one operation. Special consideration related to cement fill is needed for kyphoplasty. Along with the cement required for filling the void created by the balloon tamp, additional cement is needed to allow integration of the cement into the surrounding trabecular bone. This serves to lock in the cement. Inadequate filling may lead to further collapse of the surrounding bone from excessive motion at the interface between the bone and cement. In general, the volume of cement injected should be greater than the volume of the inflated balloon. Maintenance of the reduction via kyphoplasty may be diffi cult in certain fractures, particularly in vertebrae plana. Once the balloon is deflated, the fracture may collapse again. The reduction can be maintained by the eggshell technique.

54

III Thoracic Spine

AP c-arm

lateral c-arm head

foot

• Biplanar fluoroscopy is used throughout the procedure.


L1 vertebral body

L2 vertebral body

L3 vertebral body

cannulas placed into L3 vertebral body

• The starting position for the cannula should be at the 10 o’clock or 2 o’clock position of the pedicle (superior-lateral corner depending upon the left or right side of the spine). This position places the cannula the farthest from the exiting nerve root. The cannula is advanced such that on the AP side it never crosses the medial edge of the pedicle until it crosses the posterior verterbral body line on the lateral image.

55

56

III Thoracic Spine

L2

cannulas placed into L3 vertebral body posterior

L4

L5

L1 vertebral body

L2 vertebral

anterior


L2

L3 body

• The balloon is then inflated to create a potential space for cement augmentation.

57

58

III Thoracic Spine

L2

anterior cannulas placed into L3 posterior

L4

bone cement injected into cavities in restored L3

L5

• Cement is then added to the vertebral body under fluoroscopic visualization. The cement is carefully observed on both the AP and lateral images so that the borders of the vertebral body are not violated. If cement extravasation is noted, the procedure is terminated. Cement should be avoided in the posterior aspect of the vertebral body.


L1 vertebral body

L2 vertebral body

balloons removed, residual cavities filled with bone cement

• Ideally, cement filling should cross the midline in the AP plane.

Potential Pitfalls • poor fluoroscopic visualization due to severe osteoporosis • cement embolization • cement extravasation into the neuroforamina or spinal canal • pedicle fracture due to improper cannula insertion inadequate cement fill

59

11 Thoracic Pedicle Screw Placement

Tips and Pearls Before You Begin Meticulous dissection with exposure of the transverse processes is mandatory. Facetectomies should be performed at each fusion level, and the cartilage should be removed. Fluoroscopy or intraoperative radiographs can be used to identify the pedicle shadow. The most important anatomic landmark is the middle of the facet, as the pedicle screw start point should always be lateral to this midpoint.

T7

T6 pedicles

ribs


T7

T6

pedicles

ribs

• A burr may be used to create a pedicle blush by removing only the dorsal cortex in the area of the targeted pedicle entry point.

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III Thoracic Spine

pedicles T7

T6

ribs

• With gentle but firm ventral pressure, the gear shift should be easily wiggled into the pedicle. If any amount of significant resistance is met, the surgeon should reevaluate the starting point and trajectory of the pedicle. The gear shift should be advanced approximately 30–35 mm.


• The screw is then appropriately sized and positioned. Typical screw lengths in the lower thoracic spine average 40–45 mm, while in the upper thoracic spine lengths may be as short as 35 mm.

Potential Pitfalls • Pedicle violation medially or inferiorly may occur and result in nerve root or spinal cord injury. • Anterior cortex violation from screws that are too long may result in vascular or visceral injury. • Pedicle screw pullout or failure of fixation may occur with malpositioned pedicle screws.

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12 Minimally Invasive Thoracic Corpectomy

Tips and Pearls Before You Begin Care should be taken to obtain orthogonal fluoroscopic views of the involved vertebral level. Parallax may result in exposure of the incorrect verterbal body and improper dilator placement along the anterior vertebral body, risking damage to the great vessels. Blunt dissection is necessary to prevent perforation of the pleura. A sponge stick or peanut can be used to sweep the pleura anteriorly. If the pleura is violated, then a chest tube or red rubber catheter can be placed upon completion of surgery. In general, most patients are asymptomatic, and prompt removal of the catheter will allow rapid mobilization.

intercostal nerves

a l e r n e x t o s t a l r c i n t e s c l e s m u

T7

T11 T8 b i r h t 8

T9 lung

b

T9– T10 disk

b i r h t 0 T10 1

T10– T11 disk

b i r h t 1 1

T12


intercostal nerves

a l e r n e x t o s t a l r c i n t e s c l e s m u

rib released of neurovascular bundle

T7 T11 T8 b i r h t 8

T9 lung

b i r h t 9

T9– T10 disk

T10

T10– T11 disk

b i r h t 1 1

T12

b i r h t 2 1

b i r h t 0 1

spinous processes

• The inferior portion of the rib is subperiosteally released from the neurovascular bundle. intercostal nerves cut edge of 10th rib

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III Thoracic Spine

b r i h 7 t

lung retracted anteriorly

i r b h t 8

b i r h t 1 0

b i r h t 9

T9

T10 T11

junction of 10th rib and T10 transverse process

s p i n a l c o r d s p i n o us p r oc es se s

T12

intercostal nerves b i r h t 1 1 a o r v e t a a n a n d c a v a

L1


vena cava

T9

r a u l e p

T9– T10 disk

T10

T10– T11 disk

lung b i r h t 9

i r b h t 1 1

10th rib (resected)

b i r h t 2 1

intercostal nerves

• The intervertebral disk space above and below the involved vertebral level is subperiosteally exposed. The segmental artery has been cauterized and resected.

vena cava 10th rib (cut) anterior wall of T10

T11

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III Thoracic Spine

vena cava 10th rib (cut) anterior wall of T10

plate on T11

plate on T9 l u n g

b i r h t 1 1

b r i h 9 t

spinal canal

b i r h t 2 1

10th rib (cut)

intercostal nerves

• An expandable titanium cage has been appropriately sized and placed into the defect. A plate has been placed into the vertebral body above and below at the T9 and T11 levels, respectively.

vena cava

10th rib (cut)


Potential Pitfalls Adequate radiographic visualization is important. Improper docking of the dilator too far anteriorly may result in resection of the anterior longitudinal ligament with potential implant migration or damage to the great vessels. The segmental vessel can typically be cauterized. In situations where it continues to bleed, hemostatic agents and pressure will cause the bleeding to cease.

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IV Lumbar Spine

13 Open Laminectomy and Diskectomy

Tips and Pearls Before You Begin The ligamentum flavum is often hypertrophied as part par t of the pathologic process. In the hypertrophied state, it can become a visual barrier to precise identification of anatomic structures and may pose a physical impediment to safe entry into the spinal canal. To obviate these problems, excise the superficial layers of the ligamentum separately. A plane of dissection can be found at the lower attachment of the ligamentum to the top surface of the inferior lamina. The primary primar y connecconnection of the ligamentum is fixed to the leading surface of the inferior lamina. A hypertrophied ligamentum will generally expand posteriorly and mushroom up over the posterior, flat face of the lamina. Careful dissection with a small 2–0 or 3–0 curette, with the blunt aspect against the flat of the inferior lamina, usually defines the superficial layer for removal. The remaining deep ligamentum can then be excised. Always release the attachment of the deep layer from the undersurface of the superior lamina first (with the ligamentum still under tension). A small curette is used to sweep under the lamina. This minimizes the risk of dural tear. Releasing the inferior attachment first would slacken the ligament and require blind grasping under the superior lamina to remove the upper ligamentum. Blind use of a rongeur increases increases the risk of dural tears. If the interlaminar space requires enlargement, this is best done with a sidecutting burr. To prevent dural compromise, keep the angle of the burr perpendicular to the dura so the noncutting tip is adjacent to vital structures. A horizontal sweeping motion is used, and an inward push is avoided. Take care to preserve the pars interarticularis (7–9 mm minimum). Bites from a Kerrison rongeur may produce stress fractures in the pars.

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IV Lumbar Spine

■

Skin Incision

supraspinous ligament L5 spinous process

L4 spinous process dura L5 lamina

L5–S1 facet joint

traversing L5 nerve root over disk herniation

L4–L5 facet joint

L3 spinous process 4 n n g L t i s r e t r a v r v e r o o e n

L3–L4 facet joint

exiting nerve roots

• A midline incision is used over the levels that are to be resected.


supraspinous ligament L4 spinous process

L5 spinous process dura

L3 spinous process 4 n g L t i s r e t r a v r v e r o o e n

L3–L4 facet joint

L5–S1 facet joint exiting nerve roots

• The fascia is then identified and opened in the midline over the spinous process. Subperiosteal dissection is accomplished with a Cobb elevator.

L5–S1 facet joint

L3–L4 facet joint

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IV Lumbar Spine

L5–S1 facet joint

L4–L5 facet joint

L3–L4 facet joint

L5 spinous process

traversing L5 nerve root over disk herniation

• The inferior half of the L4 and superior half of the L5 spinous processes are removed along with the supraspinous and interspinous ligaments.

L5–S1 facet joint

L4–L5 facet joint

L3–L4 facet joint


L5–S1 facet joint

inferior remnant of L5 spinous process

L4–L5 facet joint

L5 lamina

L 5 n e r ve r oo t

L3–L4 facet joint L4 lamina

dura

superior remnant of L4 spinous process L3 spinous process

S1

t r o o e r v n e g t n i i e x

L3–L4 disk space

• The lateral recess is decompressed by undercutting the superior articular process of the inferior vertebra.

L5–S1 facet joint

inferior remnant

L4–L5 facet joint

L5

L 5 n e r ve r o o t

L3–L4 facet joint L4

superior remnant

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IV Lumbar Spine

L5–S1 facet joint

inferior half of L5 spinous process


superior half of L4 spinous process dura

S1

L3–L4 facet joint

L3 spinous process

traversing L5 nerve root retracted medially

disk herniation

• A knife is used to make an annulotomy over the disk herniation.

L5–S1 facet joint

inferior half of L5 spinous


L3–L4 facet joint superior half of L4 spinous


Potential Pitfalls If surgery is performed at the wrong level, it is usually done at the segment above the intended operation. If there is any question of the expected pathology not being found, additional confirmatory imaging should be performed to establish levels prior to incising the annulus.

79

14 Open Posterolateral Lumbar Fusion

Tips and Pearls Before You Begin In the lumbar spine, the pedicles are medially oriented, particularly in the lower lumbar segments. A lateral fluoroscopic image obtained for purposes of localization is extremely helpful in determining cephalad/caudad orientation of the pedicle. In general, the L3 pedicle is directed straight vertically toward the floor, with the upper lumbar segments angulated toward the head and the lower lumbar levels directed toward the foot. If a pedicle cannot be cannulated, a hemilaminotomy can be performed, palpating the medial wall to determine angulation.

L3 spinous process

L4 spinous process

L5 spinous process

L 5

4 g L n i s o t e r


L3 spinous process

L4 spinous process

4 n g L t i s r e t r a v r v e r o o e n

5 g L t n i s o v e r v e r o a r t e r n

t o o r e v r e n 4 L

L4 pedicle

L4–L5 facet joint

transverse process

• Resection of the facet capsule and exposure of the superior articular process (caudad vertebra) and the transverse process is essential to identify the starting point for the lumbar pedicle screw.

L4 spinous process

L3 spinous process

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IV Lumbar Spine

L3 spinous process

L4 spinous process

L 5 i n g o t s r e o t r a v e r v e r n

lateral edge of pars interarticularis

4 g L n i s t v e r o o t r a e r v e r n

L4 pedicle

L4–L5 facet joint

t o o r e v r e n transverse 4 L

process

• The pars interarticularis is used to identify the medial extent of the pedicle.

L4 spinous process

L3 spinous process

4 g L s i n t


L3 spinous process

L4 spinous process

g L 4 n i s e r o t t r a v r v e r o n e

5 g L n i t s v e r e r o o a r t e r v n

L4 pedicle

L4–L5 facet joint


transverse process

• The four walls of the pedicle are probed.

L4 spinous process

5 g L

L3 spinous process

L 4 i n g o t s r e t r a v r v e r o e

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IV Lumbar Spine

L4 spinous process

L3 spinous process L 4 i n g t s r e o t r a v r v e r o n e

5 g L t n i s o v e r e r o a r t e r v n

L4–L5 facet joint


transverse process

• The pedicle screw is placed.

Potential Pitfalls During exposure, bleeding typically occurs along the lateral aspect of the facet joint and the lateral edge of the pars interarticularis. These segmental arteries should be prophylactically cauterized with bipolar cautery; otherwise, undue time is spent obtaining hemostasis. Pedicle wall violations typically occur at the pedicle-vertebral body junction (15–20 mm in depth). If a violation occurs, the starting point of the screw can be lateralized and the angulation of the screw can

15 Minimally Invasive Lumbar Exposure

Tips and Pearls Before You Begin Radiographic visualization is extremely important both in the anteroposterior (AP) and lateral views. Often, the initial dilator can be used as a Cobb elevator, with gentle subperiosteal dissection being performed to sweep the paraspinal muscle off the lamina. Anatomic landmarks may be diffi cult to conceptualize as the surgeon adapts to the minimally invasive technique.

midline

L5 exiting nerve root

spinous processes

L5 traversing nerve root L4 L5 lamina 5 lamina

L5 pedicle

L L 4 – c e t fa n t j o i

4 – L i n t L 3 e t j o f a c

L4 pedicle

L3

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IV Lumbar Spine

midline

erector spinae muscle

traversing L5 root under L4 lamina

L5 L4 pedicle lamina targeted L4–L5 facet joint L5 exiting L3 nerve root L4 L5 pedicle L4–L5 L4 exiting disk space nerve root

15 Minimally Invasive Lumbar Exposure

midline targeted L4–L5 facet joint L5 lamina exiting L5 nerve root L5 pedicle

traversing L5 root under L4 lamina L4 pedicle

exiting L4 nerve root

L3

erector spinae muscle

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IV Lumbar Spine

midline tube retractor over L4–L5 facet

traversing L5 root under L4 lamina

L5 lamina

L4 pedicle

exiting L5 nerve root L5 pedicle

L4

L3


• The final portal is established and firmly connected to the surgical bed.

16 Minimally Invasive Laminectomy

Tips and Pearls Before You Begin Proper patient positioning and good intraoperative imaging are essential. For the given procedure, it is also important to choose the correct size for the retractor. For a decompression, a smaller diameter retractor is required to allow placement medial to the facet joint. Once the retractor is in the correct position, resist the temptation to move it often because such movement leads to creep of the muscle into the wound. If there is an incidental durotomy, it should be treated in a similar fashion to the same complication encountered in an open procedure. A primary suture repair is preferable if it is possible. Epidural bleeding needs to be proactively controlled. There are several ways to reduce the likelihood of problematic bleeding. First, positioning of the patient on the Jackson frame reduces intra-abdominal pressure. When in the epidural space, find the bleeders before they find you and use bipolar electrocautery. Liberally use a thrombotic paste product to minimize bleeding.

L5 spinous process

L5–S1

midline

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IV Lumbar Spine

midline

L5 spinous process

L5–S1 disk space

L5 pedicle

L5–S1 facet joint

5 t L o g o n r i e t v i x r e e n

l i ga me n t u f l av u m m L 5 L5 n g t i s r lamina t r a v e e r o o v n e r

L4–L5 facet joint

4 g L n i s e r o t n s v v e r o a r t n e r

L4 lamina

L3–L4 facet joint

4 t L o g o n r i e t v i x r e e n

L3–L4 disk space L4 pedicle

L4–L5 disk space

• The high-speed burr is used to remove the lamina.

L5 spinous process

midline

L4 lamina

16 Minimally Invasive Laminectomy

contralateral L5–S1 facet joint superficial midline

L4 spinous process

L5 spinous process

L3 spinous process

L4 lamina

dura deep midline L5 lamina

L5–S1 facet joint

5 i n g L t s r e t r a v v e r o o n e r

L5 pedicle

L3–L4 facet joint

L4–L5 facet joint

L4 pedicle

4 t L o g o n r i e t i v x r e e n

5 t L o g o n r i e t i v x r e e n

• Undercutting the ipsalateral L4–L5 facet joint.

contralateral L5–S1 facet joint

L5 spinous process

contralateral L5 pedicle L4 spinous process

superficial midline

L3 spinous process

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IV Lumbar Spine

contralateral L5–S1 facet joint

contralateral L5 root superficial midline

L5 spinous process

deep midline

dura L5 lamina

L5–S1 facet joint

5 t L o o g r n i e t v i x r e e n

L3 spinous process

L4 lamina

5 e r a l L t t a l i s i p v e r o o n e r

L5 pedicle

L3–L4 facet joint L4 pedicle

L4–L5 facet joint 4 t L o g o n r i e t i v x r e e n

L4–L5 disk space

• The decompression occurs with the tube directed medially; therefore, the superficial midline is crossed during the decompression. • A completed laminectomy demonstrates that the thecal sac is completely decompressed, with the overlying paraspinal muscle preserved.

Potential Pitfalls

17 Minimally Invasive Far Lateral Diskectomy

Tips and Pearls Before You Begin Far lateral disk herniations aff ect the nerve root exiting lateral to the neuroforamen. Therefore, a standard hemilaminotomy will not allow for visualization of the disk herniation without excessive or complete resection of the facet joint. L5–S1 disk herniations pose an additional anatomic challenge because the sacral ala and iliac wing will often prevent a far lateral approach.

L4

L5

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IV Lumbar Spine

5 g L t n i r s o v e v e r o a r t e r n

L4–L5 facet joint L5–S1 facet joint

disk space e r s e v s s s n c e r a r o t 5 p L

L3–L4 facet joint L 4 t o g n r o i t i e x v e r n e

L4 transverse process

• The incision is typically made 4 cm lateral to the midline. The tube is docked onto the lateral aspect of the pars interarticularis and the inferior transverse process.

5 g L t n i r s o v e v e r o a r t e r n

L5–S1 facet joint

L4–L5 facet joint

L3–L4 facet joint


4 g L t n i s v e r r o o t r a e r v e n

L4–L5 disk herniation

L4–L5 facet joint

L5–S1 facet joint L4 transverse process



• The intertransverse septum is exposed and is detached from the inferior transverse process with a curved curette.

L5–S1

L4–L5 facet joint

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IV Lumbar Spine

L4–L5 facet joint

L5–S1 facet joint

herniated disk space L5 transverse process


o t r o L 4 g n i t i e x

• The nerve root should be gently mobilized superiorly to expose the underlying disk space.

L4–L5 facet


t o o r 5 g L n i L4–L5 e r s v a facet joint t r

L5–S1 facet joint disk space L5 transverse process


t o o r v e e r n L 4

• A curette is placed into the site of the disk herniation.

L4–L5 facet joint

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Potential Pitfalls Meticulous dissection is necessary to obtain hemostasis, particularly when the intertransverse septum is resected. Bleeding, if not controlled, will result in poor visualization of the disk herniation, with a resultant inadequate decompression.

18 Minimally Invasive Transforaminal Lumbar

Interbody Fusion

Tips and Pearls Before You Begin Visualization of the disk space is essential. Complete resection of the facet joint with removal of all overlying bone from the superior articular process of the inferior vertebra should be performed. Disk space preparation is the key to an increased likelihood of a successful arthrodesis. A combination of currettes and Kerrison rongeurs should be used to prepare the end plate. Fluorscopy may be used to ensure that the anterior longitudinal ligament is not violated. Care should be taken with paddle distractors and shavers, as these devices may compromise the end plates, which can result in subsidence of the implant.

L5 spinous process

midline

dura

l ig a m e n f la v u t um m

L4 lamina pars inter-

100 IV Lumbar Spine

midline

L5 spinous process

l i ga m e n t um f la v u m L5 lamina

dura


L 4 l a m i n a

pars interarticularis

L5 pedicle

L4–L5 facet joint L5–S1 facet joint L4–L5 disk space


L4 pedicle

• Once the lamina is exposed, a high-speed burr is used to perform a laminectomy. Bone is removed until only the flavum is visualized. – The laminectomy is extended laterally through the pars interarticularis. – Bone is saved in a bone trap.

18 Minimally Invasive Tranforaminal Lumbar Interbody Fusion

midline

L5 spinous process

l ig a m e nt um f la v um

dura


L5 lamina

L4 lamina

L5 pedicle 4 t L g o o n r i t i v e x r e e n

L5–S1 facet joint

L4–L5 disk space

L4 pedicle

• The laminectomy is extended cranially until the end of the flavum insertion is identified. – Epidural fat or dura is often seen. • This marks the cranial extent of the laminectomy. • The burr is then directed directly laterally through the pars interarticularis.

101

102 IV Lumbar Spine

midline

L5 spinous process

dura

l ig a m e nt um f l av um L5 lamina

L 5 r s i n g t e v a r t r o o n e r v e

L4 lamina

L5 pedicle

L5–S1 facet joint L5 superior facet

L4–L5 disk space


• Once the burr is through the pars, the inferior articular process can be removed, completing the facetectomy and exposing the involved disk space.

L5 spinous process

midline

dura


midline

L5 spinous process

dura ligamentum flavum

5 g L n i t s v e r r o o t r a e r v e n

L5 lamina

L4–L5 disk space L4 lamina

L5 pedicle

L5–S1 facet joint L5 superior facet


• Bipolar cautery is used to coagulate the veins that overlie the disk space.

L5 spinous process

superficial midline

dura

103

104 IV Lumbar Spine

• The working space in the TLIF is lateral to the exiting root in the neuroforamen. – Lateral fluoroscopic imaging is used when preparing the disk space.


105

106 IV Lumbar Spine

• Once the disk material has been removed and the end plates prepared, a bone funnel is passed into the disk space. – The bone collected during the laminectomy can then be placed into the disk space.


deep midline

dura

L5 traversing nerve root

suction on TLIF working zone

L4 exiting nerve root

• The interbody cage has been placed into the prepared disk space. – The cage is directed obliquely toward the midline. – The tube can be directed medially to perform a contralateral decompression.

Potential Pitfalls Inadequate resection of the facet joint will lead to decreased visualization of the

107

19 Mini-Open Pedicle Screw Placement

midline

L5 spinous process

dura

l i ga m en t u m f l av u m L5 lamina

pars interarticularis 5 g L n i t s v e r e r o o a r t e r v n

L4–L5 facet joint L5–S1 facet joint

5 t L g o o n r i t e i x r v e e n

■


L4 lamina

pedicle start point

4 t L g o o n r i t i v e x r e e n

L4–L5 disk space

Step 1: Pedicle Start Point Is Identified

L4 pedicle


• Lateral fluoroscopic imaging is used to confirm the direction in the cephaladcaudal plane.

109

110 IV Lumbar Spine

■

Step 2: Pedicle Is Cannulated

• The pedicle tract is probed.


• Pedicle screws are then placed.

111

112 IV Lumbar Spine

• A rod is then placed and secured through the tube. L5 spinous process

thecal sac

20 Percutaneous Pedicle Screw Placement

2 o’clock pedicles end plate

spinous process

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IV Lumbar Spine

pedicles

spinous process

• The Jamshidi trocar is advanced 15 mm until it is centered in the pedicle.


medial edge of pedicle

• A guide wire is then advanced an additional 10 mm until it abuts the medial wall of the pedicle on the AP image.

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IV Lumbar Spine

●

medial wall of pedicle

guide wire in adjacent level

●

spinous processes

end plate

●

●

• The steps are repeated for the adjacent level. End plate visualization and centering the spinous process are essential steps for ensuring accurate percutaneous screw placement.


●

● pedicles

spinous processes

●

●

• Guide wires have been placed into both pedicles on the AP view.

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IV Lumbar Spine

posterior vertebral wall

l a n u n a c

• A lateral image is then obtained to confirm that the guide wires are past the vertebral body wall. This image is extremely important, as it confirms that the guide wire has not breached the medial wall of the pedicle before entrance into the vertebral body. A cannula is then placed in between the guide wires.


pars interarticularis

disk spaces

wor k ing d i la tor

• The working dilator is docked over the pars interarticularis and disk space level. • The disk space is prepared as previously described.

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e g u ide w i r

intervertebral cage

• The pedicles are tapped over the guide wire.

r t a p o v e i r e g u i d e w


cannulated pedicle screw (over guide wire)

intervertebral cage cannulated pedicle screw (guide wire removed)

• Cannulated pedicle screws are placed over the guide wire.

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cannulated pedicle screws

rod intervertebral cage

• The rod is passed submuscularly into the tulips of the pedicle screws after the guide wires are removed. Gentle compression can be applied to the graft.


midline (spinous processes)

pedicle screws

rod

intervertebral cage

• Final AP image, demonstrating centered cage placement and gently converging pedicle screws.

123

21 Extreme (eXtreme) Lateral Interbody Fusion

Tips and Pearls Before You Begin A good fluoroscopic image is extremely helpful. Adjust the cephalocaudal angle of the C -arm to provide a clear lateral view of the end plates. There is a tendency to cheat the initial exposure anteriorly to avoid the nerves posteriorly. However, because the retractor is designed to prevent pressure on the posterior elements, the aperture is preferentially expanded anteriorly. Therefore, the ideal initial target spot is the direct center of the lateral aspect of the disk, which will result in retractor exposure of the anterior half of the disk space. Multilevel procedures can be performed with the same skin incision but separate fascial incisions and psoas muscle dilations. In degenerative scoliosis cases, coronal alignment can be achieved from either side, but access is easier from the concave side, which allows access to multiple levels through the same incision. The contralateral annulus must be disrupted to achieve parallel distraction, optimal biomechanical position of the implant, and optimal coronal alignment.


e l l c a s n u r t e e m n u i i q l b o

lateral femoral cutaneous n. (L2–L3)

L5

L4– L5 disk

L4

L3– L4 disk

L3

geni to f e mo ra l n.

i l i a c c r e s t

psoas muscle femoral n.

iliohypogastric n.

ilioinguinal n. (L1)

• The patient is placed into a direct lateral position. • It is essential that the patient be directly perpendicular to the ground to ensure true anteroposterior (AP) and lateral fluoroscopic views of the disk space. • AP and lateral fluoroscopic imaging is used to identify the disk space.

iliohypogastric n. lateral femoral cutaneous n.

e xt e rn l

l . a n m r t e u e n i i q l b o

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126 IV Lumbar Spine

iliohypogastric n.

e xt e rn a l o b li q ue m . lat. femoral cutaneous n.

l . a n r m t e u e n l i i q b o

L4

L3– L4 disk

L3

genitofemoral n. psoas m. genitofemoral n.

i i a c r l e s c t

ilioinguinal n.

• The fibers of the internal oblique muscle lie underneath the external oblique. – These fibers run in an opposite direction.

lat. femoral cutaneous n.

t r a n f a s v s e c r i a s a l i s

l . a n r m t e u e n i q i l b o


lat. femoral cutaneous n.

L3– L4 disk

L3 genitofemoral n.

lumbar plexus lies within the psoas muscle

psoas m.

iliohypogastric n.

• The transversalis fascia is bluntly opened, exposing the retroperitoneal fat. vena cava abdominal aorta

A L L

L4

L3

127

128 IV Lumbar Spine

vena cava ab do mi na l ao r t a

A L L

L4 L5

p m u s o a s c l s e

nerve plexus

• Once the disk space is exposed, an annulotomy can be performed. – Note that the nerve root is posterior to the posterior retractor blade. vena cava abdominal aorta

L A L

L4


vena cava abdominal aorta

A L L

L4

L3

L5

p s o ( a s p l e a n d n m u s cl x u s e r v e w i t e hi n )

• An intervertebral cage is gently impacted into place. – The cage should span the entire width of the vertebral body, thereby resting on the ring apophysis. This placement will minimize the likelihood of cage subsidence. – The cage is placed using AP and lateral fluoroscopic imaging. ▫

Potential Pitfalls

129

22 Minimally Invasive Lumbar Corpectomy

Tips and Pearls Before You Begin The approach for the minimally invasive lumbar corpectomy is similar to that of the extreme lateral interbody fusion. However, care should be taken to be more anterior to the psoas muscle, because two disk space levels are treated simultaneously, which increases the likelihood of postoperative lumbar nerve root dysfunction. The upper lumbar levels (L1–L3) are much easier to treat because the psoas is less prominent at these levels and the retractor can be safely positioned anterior to the psoas. At the L4 vertebral level, the patient should be informed that there may be a chance for postoperative psoas and lower lumbar nerve root dysfunction. In the majority of cases, the dysfunction resolves within 2–4 weeks postoperatively.

genitofemoral n. segmental arteries aor t a and v ena c av a

iliac vein and artery

L4–L5 disk i l i a

L3– L4 L4 disk

L3 L2– L3 disk

a l i n t e r n m. e u q i o b l

L2 p s o as m

22 Minimally Invasive Lumbar Corpectomy

ALL n d t a a v a r o a a c a v e n

L4

L3– L4 disk

L2– L3 disk

L3

PLL

L2

psoas muscle

ascending lumbar vein

• The dilator has been docked over the pathologic vertebral body. The psoas is retracted posteriorly.

d a a n v a t r o a a c a v e n l . a m

131

132 IV Lumbar Spine

t a a o r a or t a v en a a n d c av a

L2 thin anterior wall of L3 L4

PLL

e u s c l m s p s o a nerve roots ascending lumbar vein

L2 spinous process

• The corpectomy is complete. The L2–L3 and L3–L4 disk spaces have been resected. The L3 vertebral body has been removed, leaving only a thin wall and the PLL intact. anterior rim of L3 n d t a a v a r o a a c a v e n

L2

22 Minimally Invasive Lumbar Corpectomy anterior rim of L3 n d a a v a t r a o a c a v e n

L2

L4

p s o a s m u s c l e

PLL

l e m u s c p l e x s a o p s e c o m v & n e r

ascending lumbar vein L2 spinous process

• The cage is shown in its final distracted position. The bone graft has been placed inside and around the cage.

Potential Pitfalls Care should be taken to place the tube along the medial/posterior vertebral body edge. Placement of the tube too far anteriorly will result in resection of the anterior longitudinal ligament and an inadequate spinal canal decompression. In the

133

23 Anterior Lumbar Interbody Fusion

Tips and Pearls Before You Begin Lateral fluoroscopy is helpful during preoperative localiztion. Localization will help to minimize tissue dissection and reduce surgical time. Lateral fluoroscopy is also beneficial during implant placement. The ideal implant position is a few millimeters recessed deep to the anterior margin of the adjacent end plates. The osteophytes should be rongeured off the anterior end plates before the diskectomy, as they may obscure normal anatomy and result in improper placement of the interbody implant. Once the anterior annulus is incised a Cobb elevator may be used to detach the Sharpey fibers from the superior and inferior end plates, and then the disk can be removed in one piece. Overly sclerotic end plates can be burred to expose the bleeding end plates. Sequential dilation of the disk space with sizers is an important step to distract the end plates adequately and insert a press-fit implant.

aorta

genitofemoral nerve

s a e o l c s s p u o i m l i

vena cava

L3–L4 disk L4

L4–L5 disk space hypogastric plexus over L5

ureter

ascending lumbar v. genitofemoral nerve

medial sacral artery and vein

epigastric artery


■

Exposure and Approach

• A lateral fluoroscopic image should be obtained before incision to localize the surgical level. At the L5–S1 level, the great vessels (aorta/vena cava) have bifurcated. At the L4–L5 disk space level, the great vessels are retracted to the right. At L4–L5, the ascending lumbar vein may need to be ligated to mobilize the vessels. Once the incision has been made, the fascia of the musculus rectus abdominis is incised. The fascial incision can made either horizontally (in line with the skin incision) or vertically, depending upon the surgeon’s preference.

genitofemoral nerve

aorta . m s a s o p o il i

. a c a i l i

vena cava

L3

ureter

epigastric artery

l a r n m. e t e x q u e i l b o

L3–L4 disk L4

rectus fascia

sacrum

ascending lumbar vein

135

136 IV Lumbar Spine

ureter

L3–L4 disk space

epigastric artery

genitofemoral nerve

rectus fascia hypogastric plexus over L5 c s a l i l i s e s e v

L5–S1 disk space

• The muscle belly of the rectus is mobilized. Some surgeons argue that mobilizing the lateral edge of the rectus results in denervation of the muscle, while others state that medial mobilization increases the likelihood for abdominal hernias. Posterior to the rectus is the rectus sheath, which is incised carefully, exposing the retroperitoneum.


median sacral a. ureter . a c a i l i

genitofemoral nerve L5 L5–S1 disk

epigastric artery

. v c a i l i

iliopsoas muscle internal iliac vessels

• The retroperitoneum is then swept to the left (the patient’s right). Retractors are placed along the right side of the disk space to hold the retroperitoneum out of the surgeon’s field of view. Care should be taken to identify the ureter and to retract it along with the retroperitoneal contents. At L5–S1, the median sacral artery may need to be ligated or cauterized prior to the disk space exposure. Care should be taken to retract gently against the verterbal body and disk space, thereby avoiding any undue pressure on the iliac veins.

137

138 IV Lumbar Spine

L5 L5–S1 disk space

S1

• Once the disk space is identified, an annulotomy can be made with either a knife or an electrocautery device. This procedure is similar to the end plate preparation performed during an anterior cervical diskectomy and fusion.

L5 inferior end plate

Pocket Atlas of Spine Surgery - Singh, Kern [SRG]

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