Spine Surgery VOLUME 17 NUMBER 8 AUGUST 2016

Transcription

1 Contemporary Spine Surgery VOLUME 17 NUMBER 8 AUGUST 2016 Surgical Decision Making in Cervical Spondylotic Myelopathy: Comparison of Anterior and Posterior Approach Dustin H. Massel, BS, Varun Puvanesarajah, MD, Benjamin C. Mayo, BA, Hamid Hassanzadeh, MD, Steven M. Presciutti, MD, and Frank M. Phillips, MD LEARNING OBJECTIVES: After participating in this CME activity, the spine surgeon should be better able to: 1. Describe the advantages and disadvantages associated with anterior and posterior approaches for treatment of cervical spondylotic myelopathy. 2. Evaluate clinical evidence concerning Mr. Massel and Mr. Mayo are Research Coordinators, Department of Orthopaedic Surgery,, ; Dr. Puvanesarajah is Resident, Department of Orthopaedic Surgery, Johns Hopkins Hospital, Baltimore, Maryland; Dr. Hassanzadeh is Assistant Professor, Department of Orthopaedic Surgery, University of Virginia, Charlottesville, Virginia; Dr. Presciutti is Assistant Professor, Department of Orthopaedics, Emory University, Atlanta, Georgia; and Dr. Phillips is Professor, Department of Orthopaedic Surgery, Rush University Medical Center, 611 W Harrison St, Ste 300, Chicago, IL 60612; frank.phillips@rushortho.com. All faculty and staff in a position to control the content of this CME activity, and their spouses/life partners (if any), have disclosed that they have no financial relationships with, or financial interests in, any commercial organizations related to this CME activity. anterior and posterior techniques for the treatment of cervical spondylotic myelopathy. Key Words: Anterior approach, Cervical spondylotic myelopathy, Posterior approach Degenerative disc disease of the cervical spine is a common phenomenon associated with aging. It begins with a tear in the intervertebral disc. Subsequent degeneration results in the eventual loss of disc height altering the stability and structure of the vertebral level. These common structural changes may result in spinal canal narrowing and pathologic changes at adjacent levels. Although degenerative disc disease is often asymptomatic, significant compression of the spinal cord may lead to symptomatic cervical spondylotic myelopathy (CSM), 1 commonly presenting as loss of fine motor control, incontinence, spasticity, and gait imbalance. Given the degenerative nature of the pathologic process, CSM is frequently observed in older adults, is reported to be the most common cause of myelopathy in patients older than 55 years, 2 and is the most common cause of spinal cord dysfunction in the world. 3 Although the precise incidence and prevalence of CSM are not available in the literature, it is estimated that 1.6 of every 100,000 individuals are surgically treated for this condition. 4 This statistic suggests that the number of individuals who experience CSM is much higher. Preferred initial treatment for CSM includes nonoperative modalities such as physical therapy; anti-inflammatory medications; and in some cases, a cervical collar. However, refractory cases may require surgical intervention. Current literature has demonstrated surgical decompression of the cervical spine to improve functional outcomes in patients with CSM. 5,6 Decompression can be achieved via an anterior or a posterior approach; each method of decompression has its own advantages and disadvantages. To our knowledge, there are no published randomized controlled clinical studies that compare the two approaches directly, which prevents clear conclusions from being drawn. Therefore, this review aims to summarize the current literature regarding anterior and posterior approaches for the treatment of CSM, with specific emphasis on comparing treatment safety and efficacy. ANTERIOR APPROACH TECHNIQUES The anterior approach to the subaxial cervical spine for cervical spondylosis is Lippincott Continuing Medical Education Institute is accredited by the Accreditation Council for Continuing Medical Education to provide continuing medical education for physicians. Lippincott Continuing Medical Education Institute designates this enduring material for a maximum of 1.5 AMA PRA Category 1 Credits. Physicians should only claim credit commensurate with the extent of their participation in the activity. To earn CME credit, you must read the CME article and complete the quiz and evaluation assessment survey on the enclosed form, answering at least 70% of the quiz questions correctly. This activity expires on July 31, 2017.

2 Contemporary Spine Surgery VOLUME 17 NUMBER 8 Editor-in-Chief Kern Singh, MD Associate Professor Department of Orthopedic Surgery Contributing Editor Alpesh A. Patel, MD Professor Department of Orthopaedic Surgery Northwestern University Feinberg School of Medicine Director, Northwestern Orthopaedic Spine Surgery Editorial Board Jonathan N. Grauer, MD Yale-New Haven Hospital Spine Center New Haven, CT Wellington K. Hsu, MD Northwestern University Feinberg School of Medicine Ken Ishii, MD, PhD Keio University School of Medicine Tokyo, Japan Yu-Po Lee, MD University of California, San Diego School of Medicine San Diego, California John O Toole, MD often referred to as direct decompression, denoting the direct access to the compressive, symptomatic osteophytes and degenerative disease of the anterior column. Surgical techniques using the anterior approach include anterior cervical discectomy and fusion (ACDF) and anterior cervical corpectomy and fusion (ACCF). Apart from direct decompression, other purported advantages of the anterior approach include the capacity for deformity correction and facilitated fusion. Cervical kyphosis is a commonly observed deformity in patients with CSM. Animal models have associated cervical kyphosis with demyelination and neuronal loss, 7 supporting theories that correction of cervical kyphosis may lead to more favorable postoperative outcomes. 8 An anterior approach to the neck allows for correction of the sagittal alignment of adjacent vertebral bodies, thus reducing the kyphotic deformity. Another advantage of anterior fusion is indirect opening of the foramina through manipulation of the intervertebral disc space. 9 Choosing between ACCF and ACDF can be challenging. Earlier studies demonstrated higher adverse event rates with ACCF compared with ACDF However, incomplete decompression was observed more frequently with ACDF because of a narrower surgical window. 10 In a study of 46 patients treated with either ACDF or ACCF, Liu et al 14 observed no differences in fusion rates at 3 months and comparable mean Japanese Orthopaedic Association (JOA) scores at a minimum follow-up of 5 years. The study demonstrated, however, that ACDF was associated with greater segmental lordosis at final follow-up compared with ACCF. In a meta-analysis of 6 studies, Xiao et al 15 concluded that patients undergoing ACDF or ACCF experience similar postoperative JOA scores, fusion rates, and myelopathic outcomes at last follow-up. Despite these similar outcomes, ACDF resulted in improved cervical lordosis and less perioperative morbidity than ACCF. Similarly, in a larger meta-analysis of 15 studies and 1368 patients, Wen et al 16 reported that despite increased perioperative adverse events and blood loss with ACCF, no differences in postoperative JOA or visual analog scale pain scores were observed. On the basis of the available literature, there is no definitive evidence to recommend ACDF or ACCF as superior for treatment of CSM. The decision to perform either procedure should be made on an individual patient basis, taking into consideration the specific location of the pathology and the patient s health. ACDF is probably better for isolated disc herniations, whereas ACCF is effective for patients with spondylotic changes most pronounced on the posterior aspect of the vertebral body. 17 POSTERIOR APPROACH TECHNIQUES In contrast to the anterior approach, posterior techniques indirectly decompress Frank M. Phillips, MD Sheeraz Qureshi, MD, MBA Icahn School of Medicine at Mount Sinai New York, New York Alexander R. Vaccaro, MD, PhD Rothman Institute and Sidney Kimmel Medical College at Thomas Jefferson University Philadelphia, Pennsylvania Michael Y. Wang, MD University of Miami Miller School of Medicine Miami, Florida Founding Editor Gunnar B.J. Andersson, MD, PhD Chairman Emeritus Department of Orthopedic Surgery This continuing education activity is intended for orthopaedic and neurologic surgeons and other physicians with an interest in spine surgery. Contemporary Spine Surgery (ISSN ) is published monthly by Lippincott Williams & Wilkins, Inc., Hunters Green Parkway, Hagerstown, MD Customer Service: Phone (800) , Fax (301) , or customerservice@lww.com. Visit our website at LWW.com. Copyright 2016 Wolters Kluwer Health, Inc. All rights reserved. Priority postage paid at Hagerstown, MD, and at additional mailing offices. POSTMASTER: Send address changes to Contemporary Spine Surgery, Subscription Dept., Lippincott Williams & Wilkins, P.O. 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3 AUGUST 2016 Contemporary Spine Surgery Fig. 1 Mid-sagittal, T2-weighted MRI scan of the cervical spine shows multilevel spinal cord compression with evidence of myelomalacia and preservation of cervical lordosis. the spinal cord by releasing the posterior elements, allowing posterior spinal cord drift and subsequent relief of anterior compression (Figures 1 3). Although posterior decompression is an effective method for many patients, those with significant cervical kyphosis may experience insufficient decompression because of the limited potential for posterior spinal cord drift. 18 Generally, two procedures for CSM are performed via the posterior approach: (1) cervical laminectomy and fusion (CLF); and (2) expansile cervical laminoplasty (ECL). Traditionally, laminectomy without fusion also was used; however, this technique was abandoned because of concerns of subsequent development of kyphotic deformity. Several studies have compared CLF and ECL with conflicting results. Small institutional studies with fewer than 30 patients by Heller et al 19 and Manzano et al 20 demonstrated less improvement in Nurick scores (an objective measurement of myelopathic symptoms) with CLF compared with ECL. In addition, Heller et al 19 demonstrated higher adverse event rates in the CLF cohort. In contrast, in a larger retrospective study, Woods et al 21 reported no differences in rates of adverse events and revision surgery between matched cohorts of 82 patients with CLF and 39 patients with ECL. Similarly, Lee et al 22 performed a meta-analysis comparing 290 patients with CLF and 302 patients with ECL, concluding that both techniques demonstrated similar symptomatic improvements. Analogous to the comparison of anterior techniques, CLF and ECL seem to provide similar outcomes. Therefore, the decision as to treatment technique should be made on an individual basis, taking note of radiographic factors that may complicate the procedure. COMPARISON OF ANTERIOR AND POSTERIOR TECHNIQUES Although the literature demonstrates few differences in the various techniques used from the same approach (anterior or posterior), determining whether to perform an anterior or posterior technique depends on several factors. These can be organized into two general categories: efficacy and adverse events. EFFICACY Postoperative functional outcomes frequently are used as a determinant of surgical efficacy. Several studies comparing postoperative neurologic recovery and functional improvement have been unable to demonstrate clinically or statistically significant differences between anterior and posterior approaches. Kawakami et al 23 compared two cohorts: patients with 1- or 2-level pathology and no spinal canal stenosis who were treated with ACDF; and patients with more than 2 levels of pathology or with spinal canal stenosis who were treated with posterior laminoplasty. Despite significant variation in preoperative diagnosis, the authors were unable to demonstrate significant differences in patient recovery rates when comparing anterior and posterior approaches. 23 In a comparison of 169 anterior and 95 posterior approaches, Fehlings et al 24 reported no significant differences in neurologic recovery. 24 Similarly, Wada et al 25 followed-up patients with multilevel CSM treated with subtotal corpectomy or laminoplasty for 5 years and observed no statistically significant difference in average JOA scores. Most recently, Li et al 26 demonstrated that adjusted mean postoperative JOA score, JOA score improvement, and recovery rate were not significantly different when comparing anterior and posterior approaches. Although the studies mentioned reported equivocal functional outcomes, several studies have conflicting results. Hirai et al 27 observed higher mean JOA scores and improved recovery rates at the 2-, 3-, and 5-year follow-up visits after ACDF compared with ECL. In a 2011 study by Ghogawala et al, 28 the anterior approach was associated with greater improvements in quality of life, as assessed using the Short Form-36 survey Physical Component Score, despite both approaches resulting in similar postoperative mean JOA disability scores. In contrast, Seng et al 29 observed greater improvement in JOA scores and lesser improvement in neck disability index scores at 6-month follow-up in patients treated with laminoplasty compared with those treated with ACDF. Fig. 2 Mid-sagittal CT scan shows segmental ossification of the posterior longitudinal ligament behind multiple vertebral bodies, as well as significant anterior osteophytosis in front of the C4-C5 and C5-C6 disc spaces. 3

4 Contemporary Spine Surgery VOLUME 17 NUMBER 8 Fig. 3 Mid-sagittal T2-weighted MRI scan shows effective migration of the spinal cord posteriorly, away from any anterior compression, after posterior cervical laminectomy and instrumented fusion. However, there were no significant differences in functional outcomes at 2-year follow-up. 29 Cunningham et al 30 performed a meta-analysis of four studies, reporting no significant differences in postoperative JOA scores or recovery rates when comparing patients who underwent laminoplasty versus ACDF. In contrast, Jiang et al 31 performed a meta-analysis of 13 studies and demonstrated higher postoperative JOA scores and neurologic recovery rates after ACDF or ACCF compared with laminoplasty. Although several studies have demonstrated equivalence throughout follow-up and others have suggested that anterior approaches may be more effective than posterior approaches, evidence as to which approach results in superior postoperative neurologic outcomes has not yet been reported. ADVERSE EVENTS The most commonly discussed adverse events associated with surgical treatment of CSM include airway compromise, dysphagia, dysphonia, and C5 nerve palsy; however, procedural blood loss and postoperative wound infection rates also must be considered. Although anterior exposure of the cervical spine involves more complex and potentially dangerous anatomy, which in theory means more technical expertise is required compared with treating similar pathology from a posterior approach, 9 current literature with regard to exposure-related adverse events provides inconclusive results. Variability in the invasiveness of each technique and approach factor heavily into estimated blood loss (EBL). Supported by Hirai et al 27 and Wada et al, 25 the reduced requirement for soft tissue dissection and boney resection associated with laminoplasty compared with ACCF resulted in a decreased EBL in the ACCF population. In contrast, Seng et al 29 demonstrated reduced EBL in patients treated with the anterior approach as compared with laminoplasty. Of note, the majority of the anterior approach cohort was treated with ACDF, which is expected to have reduced blood loss compared with ACCF. However, it is conceivable that manipulation of the highly vascular cervical paraspinal musculature for laminoplasty would result in greater blood loss than ACDF. Decompression of the spine is generally associated with a low infection rate; however, studies suggest this rate may be increased after a posterior approach. In a prospective multi-institutional study of 302 patients, Fehlings et al 32 observed wound infections in 4.7% of patients treated with the posterior approach compared with 0.6% of patients treated with the anterior approach. Despite this observation, several other studies have reported little difference in approach-related wound infection rate. 6,26,29 Overall, the anterior approach is associated with increased rates of adverse events after treatment of single- and multilevel CSM. 33,34 However, greater rates of C5 nerve palsy have been associated with the posterior approach. A recent meta-analysis by Shou et al 35 reported the posterior approach to be associated with a 5.8% rate of C5 nerve palsy compared with 5.2% in patients treated via an anterior approach. Posterior laminectomy and fusion procedures were associated with the highest rate of C5 nerve palsy (11.0%), whereas ACDF was associated with the lowest rate (3.3%). 35 OPPORTUNITIES FOR FUTURE RESEARCH Our summary of the literature highlights the uncertainty regarding the selection of an anterior or posterior approach. Overall, current literature and clinical studies have demonstrated relative equivalence in both efficacy and adverse event rates. Therefore, future research should focus on prospective randomized trials comparing homogeneous populations to determine long-term outcomes and approach-related revision and adverse event rates, as this may result in a clear distinction between approaches. CONCLUSION Clinically acceptable outcomes with regard to efficacy and adverse event rates have been observed after anterior and posterior decompression. However, there is no definitive evidence to support one approach over the other. Ultimately, clinical and radiographic presentation, along with the unique comorbidity profile of each patient, will determine which approach is most appropriate. Surgeons should consider the location of pathology, number of levels that require decompression, and bone quality when considering approaches. REFERENCES 1. Karadimas SK, Erwin WM, Ely CG, et al. Pathophysiology and natural history of cervical spondylotic myelopathy. Spine. 2013;38:S21-S Emery SE. Cervical spondylotic myelopathy: diagnosis and treatment. J Am Acad Orthop Surg. 2001;9: Kalsi-Ryan S, Karadimas SK, Fehlings MG. Cervical spondylotic myelopathy: the clinical phenomenon and the current pathobiology of an increasingly prevalent and devastating disorder. Neuroscientist. 2013;19: Boogaarts HD, Bartels RH. Prevalence of cervical spondylotic myelopathy. Eur Spine J. 2015;24(suppl 2): Fehlings MG, Wilson JR, Kopjar B, et al. Efficacy and safety of surgical decompression in patients with cervical spondylotic myelopathy: results of the AOSpine North America prospective multi-center study. J Bone Joint Surg Am. 2013;95: Furlan JC, Kalsi-Ryan S, Kailaya-Vasan A, et al. Functional and clinical outcomes following surgical treatment in patients with cervical spondylotic myelopathy: a prospective study of 81 cases. J Neurosurg Spine. 2011;14: Shimizu K, Nakamura M, Nishikawa Y, et al. Spinal kyphosis causes demyelination and neuronal loss in the spinal cord: a new model of kyphotic deformity using juvenile Japanese small game fowls. Spine. 2005;30:

5 AUGUST 2016 Contemporary Spine Surgery 8. Tang JA, Scheer JK, Smith JS, et al. The impact of standing regional cervical sagittal alignment on outcomes in posterior cervical fusion surgery. Neurosurgery. 2012;71: ; discussion Emery SE. Anterior approaches for cervical spondylotic myelopathy: which? When? How? Eur Spine J. 2015;24(Suppl 2): Burkhardt JK, Mannion AF, Marbacher S, et al. A comparative effectiveness study of patient-rated and radiographic outcome after 2 types of decompression with fusion for spondylotic myelopathy: anterior cervical discectomy versus corpectomy. Neurosurg Focus. 2013;35:E Rao RD, Gourab K, David KS. Operative treatment of cervical spondylotic myelopathy. J Bone Joint Surg Am. 2006;88: Song KJ, Lee KB, Song JH. Efficacy of multilevel anterior cervical discectomy and fusion versus corpectomy and fusion for multilevel cervical spondylotic myelopathy: a minimum 5-year follow-up study. Eur Spine J. 2012;21: Wang JC, McDonough PW, Endow KK, et al. A comparison of fusion rates between single-level cervical corpectomy and two-level discectomy and fusion. J Spinal Disord. 2001;14: Liu J, Chen X, Liu Z, et al. Anterior cervical discectomy and fusion versus corpectomy and fusion in treating two-level adjacent cervical spondylotic myelopathy: a minimum 5-year follow-up study. Arch Orthop Trauma Surg. 2015;135: Xiao SW, Jiang H, Yang LJ, et al. Anterior cervical discectomy versus corpectomy for multilevel cervical spondylotic myelopathy: a metaanalysis. Eur Spine J. 2015;24: Wen ZQ, Du JY, Ling ZH, et al. Anterior cervical discectomy and fusion versus anterior cervical corpectomy and fusion in the treatment of multilevel cervical spondylotic myelopathy: systematic review and a metaanalysis. Ther Clin Risk Manage. 2015;11: Yalamanchili PK, Vives MJ, Chaudhary SB. Cervical spondylotic myelopathy: factors in choosing the surgical approach. Adv Orthop. 2012;2012: Sodeyama T, Goto S, Mochizuki M, et al. Effect of decompression enlargement laminoplasty for posterior shifting of the spinal cord. Spine. 1999;24: ; discussion Heller JG, Edwards CC, 2nd, Murakami H, et al. Laminoplasty versus laminectomy and fusion for multilevel cervical myelopathy: an independent matched cohort analysis. Spine. 2001;26: Manzano GR, Casella G, Wang MY, et al. A prospective, randomized trial comparing expansile cervical laminoplasty and cervical laminectomy and fusion for multilevel cervical myelopathy. Neurosurgery. 2012;70: Woods BI, Hohl J, Lee J, et al. Laminoplasty versus laminectomy and fusion for multilevel cervical spondylotic myelopathy. Clin Orthopaed Relat Res. 2011;469: Lee CH, Lee J, Kang JD, et al. Laminoplasty versus laminectomy and fusion for multilevel cervical myelopathy: a meta-analysis of clinical and radiological outcomes. J Neurosurg Spine. 2015;22: Kawakami M, Tamaki T, Iwasaki H, et al. A comparative study of surgical approaches for cervical compressive myelopathy. Clin Orthopaed Relat Res. 2000: Fehlings MG, Barry S, Kopjar B, et al. Anterior versus posterior surgical approaches to treat cervical spondylotic myelopathy: outcomes of the prospective multicenter AOSpine North America CSM study in 264 patients. Spine. 2013;38: Wada E, Suzuki S, Kanazawa A, et al. Subtotal corpectomy versus laminoplasty for multilevel cervical spondylotic myelopathy: a longterm follow-up study over 10 years. Spine. 2001;26: ; discussion Li X, Jiang L, Liu Z, et al. Different approaches for treating multilevel cervical spondylotic myelopathy: a retrospective study of 153 cases from a single spinal center. PLoS One 2015;10:e Hirai T, Okawa A, Arai Y, et al. Middle-term results of a prospective comparative study of anterior decompression with fusion and posterior decompression with laminoplasty for the treatment of cervical spondylotic myelopathy. Spine. 2011;36: Ghogawala Z, Martin B, Benzel EC, et al. Comparative effectiveness of ventral vs dorsal surgery for cervical spondylotic myelopathy. Neurosurgery. 2011;68: ; discussion Seng C, Tow BP, Siddiqui MA, et al. Surgically treated cervical myelopathy: a functional outcome comparison study between multilevel anterior cervical decompression fusion with instrumentation and posterior laminoplasty. Spine J. 2013;13: Cunningham MR, Hershman S, Bendo J. Systematic review of cohort studies comparing surgical treatments for cervical spondylotic myelopathy. Spine. 2010;35: Jiang L, Tan M, Dong L, et al. Comparison of anterior decompression and fusion with posterior laminoplasty for multilevel cervical compressive myelopathy: a systematic review and meta-analysis. J Spinal Disord Tech. 2015;28: Fehlings MG, Smith JS, Kopjar B, et al. Perioperative and delayed complications associated with the surgical treatment of cervical spondylotic myelopathy based on 302 patients from the AOSpine North America Cervical Spondylotic Myelopathy Study. J Neurosurg Spine. 2012;16: Hartig D, Batke J, Dea N, et al. Adverse events in surgically treated cervical spondylopathic myelopathy: a prospective validated observational study. Spine. 2015;40: Edwards CC, 2nd, Heller JG, Murakami H. Corpectomy versus laminoplasty for multilevel cervical myelopathy: an independent matchedcohort analysis. Spine. 2002;27: Shou F, Li Z, Wang H, et al. Prevalence of C5 nerve root palsy after cervical decompressive surgery: a meta-analysis. Eur Spine J. 2015;24(12):

6 Contemporary Spine Surgery VOLUME 17 NUMBER 8 CME Quiz To earn CME credit, you must read the CME article and complete the quiz and evaluation assessment survey on the enclosed form, answering at least 70% of the quiz questions correctly. Select the best answer and use a blue or black pen to completely fill in the corresponding box on the enclosed answer form. Please indicate any name and address changes directly on the answer form. If your name and address do not appear on the answer form, please print that information in the blank space at the top left of the page. Make a photocopy of the completed answer form for your own files and mail the original answer form to Lippincott Williams & Wilkins, Continuing Education Department, P.O. Box 1543, Hagerstown, MD by July 31, Only two entries will be consi dered for credit. For more information, call (800) Online quiz instructions: To take the quiz online, log on to your account at and click on the CME tab at the top of the page. Then click on Access the CME activity for this newsletter, which will take you to the log-in page for Enter your username and password. Follow the instructions on the site. You may print your official certificate immediately. Please note: Lippincott CME Institute, Inc., will not mail certificates to online participants. Online quizzes expire on the due date. The American Association of Neurological Surgeons (AANS) manually tracks AMA PRA Category 1 Credits earned from neurosurgery activities not sponsored or joint-sponsored by the AANS. As a service to AANS members, Lippincott CME Institute will continue to provide the AANS a monthly listing of their participants and the CME credits they earned so that AANS members do not have to send their individual certificates to the AANS for tracking. Credits related to activities on orthopaedics may be applied to American Board of Orthopaedic Surgery Maintenance of Certification. Please confirm credit for specific activity with the Board at 1. You are considering anterior cervical fusion for a 59-year-old woman with CSM. Which one of the following outcomes has not been demonstrated with ACDF versus ACCF? A. Improved cervical lordosis after ACDF B. Less perioperative morbidity after ACDF C. Greater blood loss after ACCF D. Increased postoperative pain after ACCF E. Increased risk for adverse events after ACCF 2. CSM can be treated by all of the following anterior or posterior approaches except A. ACDF B. laminectomy without fusion C. cervical laminectomy and fusion D. ACCF E. expansile cervical laminoplasty 3. You evaluate a 58-year-old man who is myelopathic. His MRI scan reveals cord compression, mostly from a large extruded disc fragment from the C5-C6 disc that has migrated caudally behind the C6 vertebral body. Which one of the following is the best approach in this case? A. ACDF B. Laminoplasty C. Laminectomy D. ACCF E. Combined anterior-posterior 4. Postoperative radiculopathy is a known adverse event of posterior decompression in the treatment of CSM. One potential mechanism is thought to be tethering of the nerve root with dorsal migration of the spinal cord. Which one of the following is the most common radicular pattern seen with this condition? A. Sensory-dominant with pain in the lateral shoulder B. Sensory-dominant with pain in the lateral forearm C. Motor-dominant with weakness of the triceps D. Motor-dominant with weakness of the wrist extensors E. Motor-dominant with weakness of the deltoid 5. With regard to question 4, to which one of the following nerve roots does this palsy correspond? A. C3 B. C4 C. C5 D. C6 E. C7 6. A 61-year-old woman presents with worsening myelopathic symptoms, for which she recently had to start using a wheelchair. Radiographs reveal maintained cervical lordosis. MRI reveals cord compression from 4 disc levels. Which one of the following is the most appropriate treatment? A. Laminoplasty B. Multilevel ACCF with stabilization C. Continued nonoperative treatment D. Multilevel ACDF with stabilization E. Laminectomy alone 7. A 60-year-old woman presents with 24 months of increasing clumsiness in her hands. On physical examination, she is frankly myelopathic. She has 5/5 strength in all of her major muscle groups. MRI reveals cerebrospinal fluid effacement and retrodiscal cord compression at C5-C6 and C6-C7. Which one of the following is the most appropriate treatment? A. Laminectomy at C5, C6, and C7 B. Foraminotomy at C6 and C7 C. Physical therapy and an epidural corticosteroid injection D. C5-C6 and C6-C7 ACDF E. Physical therapy, close observation 8. Which one of the following techniques may be associated with improved clinical outcomes for treatment of CSM? A. ACDF B. ACCF C. Anterior cervical arthrodesis D. Posterior cervical arthrodesis E. Laminoplasty 9. Which one of the following scenarios provides the strongest indication to perform a combined anterior-posterior decompression for multilevel CSM? A. Postlaminectomy kyphosis of 20 degrees B. Ossification of the posterior longitudinal ligament occupying 30% of the canal C. Herniated discs at 2 continuous levels D. Herniated discs at 3 continuous levels E. Cervical kyphosis of 5 degrees 10. A 68-year-old woman presents with a loss of manual dexterity; a broad-based, shuffling gait; and exaggerated deep tendon reflexes in the lower extremities. Radiographs reveal an overall cervical kyphosis of 15 degrees. Which one of the following is the most appropriate treatment? A. C3-C6 laminectomy and fusion B. C3-C6 laminectomy C. C3-C6 laminoplasty with plate fixation D. Multilevel ACDF with stabilization E. Immobilization in halo traction for 4 weeks, followed by physical therapy 6