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Cervical Spondylotic Myelopathy: Methodological Approaches to Evaluate the Literature and Establish Best Evidence

Skelly, Andrea C. PhD, MPH*; Hashimoto, Robin E. PhD*; Norvell, Daniel C. PhD*; Dettori, Joseph R. MPH, PhD*; Fischer, Dena J. DDS, MSD, MS*; Wilson, Jefferson R. MD; Tetreault, Lindsay A. HBSc; Fehlings, Michael G. MD, PhD, FRCSC, FACS§

doi: 10.1097/BRS.0b013e3182a7ebbf
Methodology

Study Design. Review of methods.

Objective. To provide a detailed description of the methods undertaken in the articles in this focus issue pertaining to cervical spondylotic myelopathy (CSM) and ossification of the posterior longitudinal ligament (OPLL) and to describe the process used to develop summary statements and clinical recommendations regarding factors associated with the mechanisms, diagnosis, progression, and treatment of CSM and OPLL.

Summary of Background Data. We present methods used in conducting the systematic, evidence-based reviews and development of expert panel summary statements and clinical recommendations of the mechanisms, diagnosis, progression, and treatment of CSM and OPLL. Our intent is that clinicians will combine the information from these systematic reviews, narrative reviews, and primary research studies with an understanding of their own capacities and experience to better manage patients with CSM or OPLL and consider future research for the diagnosis and treatment of these diseases.

Methods. For the systematic reviews, which make up the bulk of the studies in this focus issue, a systematic search and critical review of the English language literature was undertaken for articles published on the mechanisms, diagnosis, progression, and treatment of CSM and OPLL. Articles were screened for relevance using a priori criteria and relevant articles were critically reviewed. Whether an article was included for review depended on whether the study question was descriptive, one of therapy, or one of prognosis. The strength of evidence for the overall body of literature in each topic area was determined by 2 independent reviewers considering risk of bias, consistency, directness, and precision of results using a modification of the Grading of Recommendation Assessment, Development and Evaluation criteria. Disagreements were resolved by consensus. Findings from articles meeting inclusion criteria were summarized. From these summaries, summary statements or clinical recommendations were formulated among subject experts through a modified Delphi process using the Grading of Recommendation Assessment, Development and Evaluation approach. Methods for the 2 primary research studies and the narrative reviews are also reviewed.

Results. Because of the nature of questions that needed to be addressed, not all studies in this focus issue were amenable to systematic review. As a result, this focus issue consists of several different article types, including 1 research protocol, 2 primary research studies, 2 narrative literature reviews, 7 systematic reviews, and 3 articles that combine a systematic review component with either a narrative section (n = 2) or a provider survey (n = 1). In general, the strength of evidence ratings ranged from insufficient to moderate. Summary statements or clinical recommendations were made according to available evidence and study type: 16 summary statements were made across 8 articles, and 17 clinical recommendations were made across 9 articles. Three articles had both summary statements and clinical recommendations, 5 had summary statements only, 6 had clinical recommendations only, and 1 (the research protocol) was not amenable to either.

Conclusion. Systematic reviews, narrative reviews, and primary research studies were undertaken to understand the mechanisms, diagnosis, progression, and treatment of CSM and OPLL and to provide summary statements and clinical recommendations. This article reports the methods used in the studies in this focus issue.

Summary Statements. The objectives of this focus issue were met using a variety of article and study designs, each of which has some unique methodological aspects associated with it. The reader should refer to the full article in this issue for additional details specific to that topic. The methods for systematic review follow accepted standards for rigor and, together with the application of Grading of Recommendation Assessment, Development and Evaluation, are intended to allow for transparency in the process for creating the clinical recommendation.

Cervical spondylotic myelopathy (CSM) is a complex, multifaceted disorder that is characterized by progressive compression of the spinal cord due to extradural spinal degenerative pathology. Many aspects of the pathophysiologic mechanisms, diagnosis, progression, and treatment of CSM are not well characterized. Given this critical knowledge gap, the AOSpine North America Clinical Research Network put together an expert, multidisciplinary panel to critically evaluate the literature (using systematic and narrative reviews), undertake preliminary analyses related to the impact of spinal deformity on CSM, and to complete an international survey of clinical perspectives on the management of mild CSM. This article discusses, in detail, the unique methodology employed to achieve the goals of this Focus issue devoted to CSM.

*Spectrum Research, Inc., Tacoma, WA

Department of Surgery, Divisions of Neurosurgery and Orthopedic Surgery, Spinal Program, University of Toronto, Toronto, Ontario

Institute of Medical Sciences University of Toronto, Toronto Western Hospital, Toronto, Ontario, Canada; and

§Neurosurgery, Neural Repair and Regeneration, Neuroscience Program, and Spinal Program, Toronto Western Hospital, Toronto, Ontario, Canada.

Address correspondence and reprint requests to Andrea C. Skelly, PhD, MPH, Spectrum Research, Inc., 705 S 9th, Ste. 203, Tacoma, WA 98405; E-mail: andrea@specri.com

Acknowledgment date: June 11, 2013. First revision date: July 25, 2013. Acceptance date: August 2, 2013.

The manuscript submitted does not contain information about medical device(s)/drug(s).

Supported by AOSpine North America, Inc. Analytic support for this work was provided by Spectrum Research, Inc., with funding from the AOSpine North America.

Relevant financial activities outside the submitted work: support for travel, fees for participation in review activities, and payment for writing or reviewing the manuscript.

© 2013 by Lippincott Williams & Wilkins