Search

Study design Systematic review. Objective To determine whether there are magnetic resonance imaging (MRI) characteristics in patients with cervical spondylotic myelopathy that affect treatment decisions or predict postsurgical outcomes or adverse events. Summary of background data Although the role of MRI in confirming the clinical diagnosis of cervical spondylotic myelopathy and directing surgical management is well established, its potential value as a prognostic tool is largely unknown. Methods A systematic search was conducted using PubMed and the Cochrane Collaboration Library for articles published between January 1, 1956, and November 20, 2012. The overall body of evidence with respect to each clinical question was determined on the basis of precepts outlined by the Grading of Recommendation Assessment, Development and Evaluation Working Group and recommendations made by the Agency for Healthcare Research and Quality. Results The initial search yielded 268 citations. Twenty publications met all inclusion criteria and were included in the review. Three of these assessed MRI predictors of clinical deterioration in the case of conservative treatment and 17 evaluated MRI anatomic or cord characteristics that could predict surgical outcome or adverse events. There is low evidence suggesting that a high signal intensity (SI) grade on T2WI is not associated with patient deterioration during conservative treatment. High SI grade on T2WI, along with compression ratio and canal diameter, was not an important predictor of outcome. There is low evidence identifying number of high SI segments on T2WI, low SI segments on T1WI, combined T1/T2 SI, and SI ratio as important negative predictors of surgical outcome. Conclusion On the basis of this review and on low-quality evidence, we have identified 3 important negative predictors of surgical outcome: number of high SI segments on T2WI, combined T1/T2 signal change, and SI ratio.EVIDENCE-BASED CLINICAL RECOMMENDATIONS: Recommendation 1 We suggest that when clinically feasible, surgeons rely on MRI to confirm the diagnosis of CSM and rely on clinical history and examination to determine progression and severity of disease. Overall strength of evidence Low. Strength of recommendation Weak. Recommendation 2 T2 signal may be a useful prognostic indicator when used in combination with low SI change on T1WI, or as a ratio comparing compressed with noncompressed segments, or as a ratio of T2 compared with T1WI. We suggest that if surgeons use MRI signal intensity to estimate the risk of a poor outcome after surgery, they use high SI change on T2WI in combination with other signal intensity parameters, and not in isolation. Overall strength of evidence Low. StrENGTH OF RECOMMENDATION: Weak.

STUDY DESIGN Literature review. OBJECTIVE To identify case series that have been confused with cervical spondylotic myelopathy (CSM) to develop a comprehensive differential diagnosis. SUMMARY OF BACKGROUND DATA Myelopathy can be caused by a number of different etiologies. In those patients with CSM, the presentation is not always clear. Distinct radiographical and clinical characteristics, which are not always obvious, aid in arriving at the correct diagnosis. METHODS A PubMed search was done to identify reports written in English describing conditions that may present in a manner similar to CSM to differentiate them from CSM. Material from review articles and relevant textbooks was also considered. Information regarding the number of patients, the specific diagnosis presenting as myelopathy, the diagnostic findings, and the method(s) for distinguishing CSM from the initial diagnosis was abstracted from included articles. Salient features of the conditions were summarized. RESULTS A total of 35 citations (totaling 474 patients) that reported on diagnoses confused with CSM based on clinical presentation were included. All were case reports or small case series. The differential diagnoses were organized into 7 categories: congenital/anatomic, degenerative, neoplastic, inflammatory/autoimmune, idiopathic, circulatory, and metabolic. The primary conditions in the differential included amyotrophic lateral sclerosis, multiple sclerosis, syringomyelia, and spinal tumors. CONCLUSION In the vast majority of cases, magnetic resonance imaging was an invaluable tool in determining the correct diagnosis. Electrodiagnostic studies, cerebrospinal fluid profile, unique symptomatology, and consideration of patient demographics can also aid in the diagnosis. Bilateral sensory complaints in the hands are suspicious for cervical cord pathology and MR imaging of the same should be done even if the electromyography/nerve conduction studies (NCS) suggest bilateral carpal tunnel syndrome. SUMMARY STATEMENTS: Physical exam findings are not always consistent with severity of disease in CSM; therefore, correlation to plain radiographs, MRI, and patient symptomatology is essential for arriving at the correct diagnosis. In some cases where these studies are still equivocal, use of other studies should be considered including electrodiagnostic studies as well as cerebrospinal fluid examination.

Study Design. Systematic review. Objective. To answer the following 3 clinical questions: (1) What is the evidence supporting a heritable predisposition for cervical spondylotic myelopathy (CSM) and ossification of the posterior longitudinal ligament (OPLL)? (2) What specific genetic polymorphisms have been associated with CSM and OPLL? (3) What is the evidence supporting a genetic basis for predicting postoperative outcomes for patients with CSM and OPLL? Summary of Background Data. OPLL and CSM are thought to be multifactorial conditions resulting from a combination of environmental and genetic factors. Methods. A systematic review of the English language literature was undertaken for articles published between 1980 and November 7, 2012. The strength of evidence was determined by 2 independent reviewers using the Grading of Recommendation Assessment, Development and Evaluation (GRADE) criteria for studies addressing the first question of heritability and using the criteria set forth by the HuGENet Working Group in the Venice Interim Guidelines to address the last 2 questions of genetic association. Results. Of the 118 citations identified through the initial literature search, a total of 23 articles remained after application of inclusion/exclusion criteria. The 3 family association studies related to question 1 supported the principle of an inherited predisposition to CSM and OPLL; however, the strength of evidence supporting these findings was low. Within the 19 case-control studies related to question 2, 2 single nucleotide polymorphisms (COL6A1/Intron 32(−29) and COL11A2/Intron 6(−4)) were observed at higher frequencies in OPLL cases than in controls in more than 1 study and may be associated with its development. There was insufficient evidence to support an association between CSM and any specific single nucleotide polymorphism or haplotype or to support the association of specific gene alleles with postoperative CSM outcomes. Conclusion. Existing family studies provide support for the principle of an inherited predisposition to CSM and OPLL. Multiple studies support the association of 2 collagen gene related single nucleotide polymorphisms with OPLL; however, there is insufficient evidence to support the association between CSM and any genetic polymorphism or to support a genetic predictor of surgical outcome. Conclusion. Summary Statements. Conclusion. Statement 1: Existing family studies provide support for the principle of an inherited predisposition to CSM and OPLL. Conclusion. Statement 2: Two SNPs related to the collagen 6A1 gene (COL6A1/Intron 32(−29)) and the collagen 11A2 gene (COL11A2/Intron 6(−4)) have been associated with OPLL in multiple studies and may be associated with its development. Conclusion. Statement 3: No statement can be made from the literature regarding the association of specific SNPs or haplotypes with CSM. Conclusion. Statement 4: No statement can be made from the literature regarding genetic predictors of surgical outcome in the context of OPLL or CSM.

Study design Systematic review. Objective We performed a systematic review to determine the risk and to define potential identifiable risk factors for the development of adjacent segment pathology (ASP) after cervical fusion surgery. Summary of background data During the past several decades, the indications for spinal arthrodesis have expanded, with a dramatic increase in the rate of cervical spine fusion in the United States during the past decade. However, as more of these procedures are performed over time, there have been concerns regarding the potential for these patients to develop changes at levels adjacent to the index procedure. Questions remain whether the development of clinical ASP (CASP) are iatrogenic in nature or part of natural history. Methods A systematic review of the literature was undertaken for articles published in English language between 1990 and March 15, 2012. Electronic databases and reference lists of key articles were searched to identify articles reporting risk factors for CASP after cervical fusion. Two independent reviewers assessed the level of evidence and the overall quality of the literature using the Grades of Recommendation Assessment, Development, and Evaluation criteria. Disagreements were resolved by consensus. Results We identified 5 studies (4 retrospective cohorts, 1 database study) from our search strategy that met the inclusion criteria from a total of 176 possible studies for review. The prevalence of CASP ranged from 11% to 12% at 5 years, 16% to 38% at 10 years, and 33% at 17 years. Factors that may contribute to the development of CASP include age less than 60 years, fusing adjacent to the C5-C6 and/or C6-C7 levels, a pre-existing disc herniation, and/or dural compression secondary to spinal stenosis with a mean anteroposterior diameter spinal canal of 13 mm or smaller. Conclusion CASP remains a controversial topic despite multiple attempts of elucidating an iatrogenic effect of spinal fusion versus the natural history of spinal degeneration. The mean rate of the development of symptomatic degeneration in the cervical spine after arthrodesis is estimated between 1.6% and 4.2% per year. The mean rate of reoperation for CASP is estimated at 0.8% per year. In addition, fusing adjacent to but not including the C5-C6 and/or C6-C7 disc spaces seems to consistently increase the risk of developing CASP. Consensus statement 1. The risk of developing new symptoms secondary to adjacent segment pathology causing radiculopathy and/or myelopathy after cervical fusion surgery ranges from a cumulative rate of 1.6% to 4.2% per year. Strength of Statement: Strong. 2. The risk of developing adjacent-level symptoms may be increased if disc protrusion, disc degeneration, or cord effacement is present at C5–C6 and/or C6–C7 and if those levels are adjacent to the planned surgical level. Strength of Statement: Strong.

Study design Systematic review. Objective To determine the population risk of radiographical degeneration in the lumbar and cervical spine as well as the risk of adjacent segment pathology (ASP) among patients who receive and do not receive (but were eligible for) fusion for lumbar or cervical degeneration. Summary of background data The etiology of ASP remains unclear. It has been suggested that ASP results because of a biomechanical stress transfer from the fusion. It has also been suggested that ASP is a continuation of natural arthritic disease. We sought to examine the literature and compare the rates of spinal degeneration without fusion and the rates of adjacent segment degeneration. Similarities or differences may yield insight into the etiology of ASP. Methods A systematic review of the English language literature was undertaken for articles published between 1990 and March 15, 2012. Electronic databases and reference lists of key articles were searched to identify articles reporting prevalence and/or incidence of radiographical spinal degeneration (de novo degeneration) or radiographical adjacent segment pathology (RASP) (degeneration after fusion). Two independent reviewers assessed the level of evidence and the overall quality of the literature using the Grades of Recommendation Assessment, Development and Evaluation criteria. Disagreements were resolved by consensus. Results We identified 15 studies from our search strategy that met the inclusion criteria from a total of 235 possible studies. Various definitions of radiographical spinal degeneration were used across the studies. For the population risk of radiographical lumbar and cervical spine degeneration, the cumulative incidence ranged from 12.7% to 51.5% during a 5- to 25-year period across 3 studies. One study of the cervical spine reported that there was a baseline prevalence of disc degeneration of 21.7% and, in their follow-up study, reported that 47.9% of individuals had evidence of progression of degeneration during a mean 5.8-year follow-up. The rate of progression per 100 person-years showed an age- and sex-specific trend, with females progressing at a faster rate than males through the 50s, males progressing faster than females during the 60s and 70s, with rates becoming identical in the 80s. Regarding age-specific risk, the prevalence of lumbar degeneration increased with age across 2 studies. For RASP following fusion, the cumulative incidence ranged from 6.3% to 44.4% during 6 to 12.6 years of follow-up across the 7 studies; the risk of cervical RASP was higher than that of lumbar despite the shorter mean follow-up periods. Conclusion RASP may occur at a higher rate than natural history and suggests that another factor (such as biomechanical effect of fusion) may accelerate pathologic changes. Consensus statement ASP may occur at a higher rate than natural spinal degeneration and suggests that another factor (such as biomechanical effect of fusion) may accelerate pathologic changes. Strength of Statement: Weak.