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Guideline Summary
Guideline Title
The natural history of cervical spondylotic myelopathy.
Bibliographic Source(s)
Matz PG, Anderson PA, Holly LT, Groff MW, Heary RF, Kaiser MG, Mummaneni PV, Ryken TC, Choudhri TF, Vresilovic EJ, Resnick DK, Joint Section on Disorders of the Spine and Peripheral Nerves [trunc]. The natural history of cervical spondylotic myelopathy. J Neurosurg Spine. 2009 Aug;11(2):104-11. [20 references] PubMed External Web Site Policy
Guideline Status

This is the current release of the guideline.

Scope

Disease/Condition(s)

Cervical spondylotic myelopathy

Guideline Category
Counseling
Management
Clinical Specialty
Chiropractic
Family Practice
Geriatrics
Internal Medicine
Neurological Surgery
Neurology
Orthopedic Surgery
Physical Medicine and Rehabilitation
Preventive Medicine
Sports Medicine
Intended Users
Physicians
Guideline Objective(s)
  • To address questions regarding the therapy, diagnosis, and prognosis of cervical degenerative disease using an evidence-based approach
  • To use evidence-based medicine to delineate the natural history of cervical spondylotic myelopathy (CSM) and identify factors associated with clinical deterioration
Target Population

Patients with cervical degenerative disease and cervical spondylotic myelopathy

Interventions and Practices Considered
  1. Surgical intervention
  2. Nonoperative management options
  3. Discussion of the natural history of cervical spondylotic myelopathy
  4. Surgical intervention for patients with cervical stenosis without myelopathy who either have abnormal electromyography (EMG) findings or clinical radiculopathy
Major Outcomes Considered
  • The modified Japanese Orthopaedic Association (mJOA) and Nurick scales
  • Abnormalities on magnetic resonance imaging (MRI)
  • Changes on electrophysiological testing

Methodology

Methods Used to Collect/Select the Evidence
Hand-searches of Published Literature (Secondary Sources)
Searches of Electronic Databases
Description of Methods Used to Collect/Select the Evidence

Search Criteria

The expert group completed a computerized search of the National Library of Medicine database and the Cochrane database of the literature published from 1966 to 2007 using search terms and MeSH headings. A search using the subject heading "spondylosis and myelopathy" yielded 754 citations. The expert group combined the following subject headings with 'spondylosis and myelopathy": "disease progression" (18 citations), "outcome assessment" (113 citations), "signs and symptoms" (142 citations), "pathophysiology" (171 citations). Also searched were terms "cervical spine and natural history" (111 citations) and "cervical spine and myelopathy and natural history" (20 citations). Accounting for redundancy, the group acquired 438 citations; they selected only English citations. The expert group then reviewed the titles and abstracts of the articles and culled additional references from the bibliographies.

Among the articles reviewed, the expert group included 32 studies and reviews that dealt with cervical spondylotic myelopathy (CSM) and its progression and outcome without surgical intervention (see Table 1 in the original guideline document). Seventeen of these studies examined outcomes over a period permitting longitudinal follow-up.

Number of Source Documents

32 studies and review articles were included.

Methods Used to Assess the Quality and Strength of the Evidence
Expert Consensus
Weighting According to a Rating Scheme (Scheme Given)
Rating Scheme for the Strength of the Evidence

Strength of the Evidence

Class I: Evidence evolved from well-designed randomized controlled trials (RCTs).

Class II: Evidence arose from RCTs with design problems or from well-designed cohort studies.

Class III: Evidence arose from case series or poorly designed cohort studies.

Methods Used to Analyze the Evidence
Systematic Review with Evidence Tables
Description of the Methods Used to Analyze the Evidence

Quality of Evidence

The guidelines group assembled an evidentiary table summarizing the quality of evidence.

The mainstay of any evidence-based review lies in the assessment of the quality of strength of the data. The group assessed the methodology of each manuscript carefully and assessed each study according to its relevant category—diagnosis, therapy, prognosis, or harm. The group applied a weighting scheme according to the methods delineated by Sackett and colleagues. After review of the study methods, the group determined how well each individual study met the validity requirements within its category and assigned a class to the study. In keeping with prior surgical guidelines, a 3-class system (Classes I, II, and III) was used (see the "Rating Scheme for the Strength of the Evidence" field).

It was the group's conclusion that expert opinion and case reports did not add significantly to the evidence used for the formulation of recommendations and should not be separately classified.

When disagreement arose as to the strength of evidence (that is, determining how well the methods conformed to the weighting scheme), the group resolved said disagreement by expert consensus within itself. To avoid the undue influence of a single individual, each member had the opportunity to list the reason(s) why a study should be downgraded or upgraded. Group members then prioritized each reason. If a reason had low priority, it was eliminated. Ultimately, there was convergence of opinion within the group. The result was unanimity to support publicly the assessment of the quality of evidence and the strength of the guidelines despite potential individual reservations regarding specific details.

Methods Used to Formulate the Recommendations
Expert Consensus (Consensus Development Conference)
Description of Methods Used to Formulate the Recommendations

In March 2006, the Joint Section on Disorders of the Spine and Peripheral Nerves of the American Association of Neurological Surgeons/Congress of Neurological Surgeons compiled an expert group to perform an evidence-based review of the clinical literature on the management of cervical degenerative spine disease. Comprising the group were spinal neurosurgeons and orthopedic surgeons active in the Joint Section and/or the North American Spine Society. This combination of specialties ensured the comprehensive participation of both surgical specialties. At least half of the group had participated in prior guidelines development, and several had completed the evidence-based course developed by the North American Spine Society. The multiple recommendations represent the product of this group with input from the Guidelines Committee of the American Association of Neurological Surgeons/Congress of Neurological Surgeons.

Formulation and Strength of Recommendations

The group formulated recommendations using expert consensus in a consensus development conference. After assessment of the quality and strength of evidence, the assigned subgroup summarized the studies leading to the basis of the Scientific Foundation section of each chapter. In general, if high-quality (Class I or II) data were available on a particular topic, poorer quality evidence was only briefly summarized. If no high-quality evidence existed, Class III data formed the basis of the scientific foundation. Based on the quality and strength of data, each subgroup formulated initial treatment recommendations. Each subgroup presented these to the entire group whose membership included active members of the Congress of Neurological Surgeons, the American Association of Neurological Surgeons, the North American Spine Society, and the American Academy of Orthopedic Surgery. The presentation was a plenary session acting as a consensus development conference from which final recommendations arose.

The group gave each recommendation a grade for strength based on the quality of the underlying studies. Grading was based on the methods of the Scottish Intercollegiate Guidelines Network and also mirrored that used by the Oxford Centre for Evidence-Based Medicine (www.cebm.net External Web Site Policy) (see the "Rating Scheme for the Strength of the Recommendations" field).

Rating Scheme for the Strength of the Recommendations

Strength of the Recommendations

Grade A: Recommendations based on consistent Class I studies.

Grade B: Recommendations based on a single Class I study or consistent Class II studies.

Grade C: Recommendations based on a single Class II study.

Grade D: Recommendations based on Class III or weaker data, or based on inconsistent data.

Cost Analysis

A formal cost analysis was not performed and published cost analyses were not reviewed.

Method of Guideline Validation
External Peer Review
Internal Peer Review
Description of Method of Guideline Validation

Validation was done through peer review by the Joint Guidelines Committee of the American Association of Neurological Surgeons/Congress of Neurological Surgeons and through external peer review prior to publication.

Recommendations

Major Recommendations

The rating schemes used for the strength of the evidence (Class I-III) and the grades of recommendations (A-D) are defined at the end of the "Major Recommendations" field.

Recommendations

  • In younger patients with mild cervical spondylotic myelopathy (CSM) (age younger than 75 years and modified Japanese Orthopaedic Association [mJOA] scale score >12), it is recommended that both operative and nonoperative management options be offered, as objectively measurable deterioration in function is rarely seen acutely (Quality of evidence: Class I; Strength of recommendation, B).
  • It is recommended that both operative and nonoperative management options be offered to younger patients with mild CSM given that the evidence indicates that clinical gains after nonoperative treatment are often maintained over 3 years in 70% of cases (Quality of evidence, Class III; Strength of recommendation, D).
  • It is recommended that discussion of the natural history of CSM conveys that the course of CSM is mixed, with many patients experiencing a slow, stepwise decline. Discussion should address the fact that long periods of quiescence are not uncommon and that a subgroup of patients may have interim improvement (Quality of evidence, Class III; Strength of recommendation, D).
  • It is also recommended that discussion of the natural history of CSM convey that long periods of severe stenosis over many years are associated with demyelination of white matter and may result in necrosis of both gray and white matter leading to potentially irreversible deficit (Quality of evidence Class III; Strength of recommendation, D).
  • It is recommended that operative therapy be offered to patients with severe and/or long lasting symptoms, because the likelihood of improvement with nonoperative measures is low (Quality of evidence Class III; Strength of recommendation, D).
  • In patients with cervical stenosis without myelopathy who either have abnormal electromyography (EMG) findings or clinical radiculopathy, decompression should be considered (if the patient does not otherwise require surgery for radiculopathy) because the presence of EMG abnormalities or clinical radiculopathy is associated with development of symptomatic CSM in this patient population (Quality of evidence, Class I; Strength of recommendation, B).

Summary

Clinical studies have not been strong in defining the natural history of CSM. There is Class III evidence that the natural history of CSM may be mixed with many patients experiencing a slow, stepwise decline. Long periods of quiescence are not uncommon, however, and a subgroup of patients may improve. There is Class III evidence from 3 pathological studies associating CSM of several years' duration with demyelination of white matter. Severe stenosis may ultimately result in necrosis of both gray and white matter (Class III).

In patients younger than 75 years of age with mild CSM (mJOA scale score >12), there is Class I evidence that associates nonoperative management with a stable clinical course over a 36-month period. In these patients, Class I evidence indicates that the mJOA scale score, 10-m walk times, and activities of daily living (ADL) assessments typically do not worsen over this time frame. Class III evidence indicates that clinical gains associated with nonoperative treatment are often maintained over 3 years in 70%.

With regard to predictive factors, Class I evidence demonstrates that EMG abnormalities in the anterior horn cells or the presence of clinical radiculopathy are associated with development of CSM in patients with asymptomatic stenosis. The importance of these findings in an asymptomatic individual is debatable.

A common theme in all studies of natural course was possible selection bias. Many studies analyzed patients with CSM after completion of conservative or surgical treatment. It was not clear which selection criteria were used to determine who should receive conservative therapy. It is very likely that patients with more severe symptoms were excluded from the studies. In most analyses, ~ 20% of patients who initially underwent conservative treatment ultimately received surgery. What is unclear is the number of patients with CSM who were initially stratified to surgical therapy.

Definitions:

Strength of the Evidence

Class I: Evidence evolved from well-designed randomized controlled trials (RCTs).

Class II: Evidence arose from RCTs with design problems or from well-designed cohort studies.

Class III: Evidence arose from case series or poorly designed cohort studies.

Strength of the Recommendations

Grade A: Recommendations based on consistent Class I studies.

Grade B: Recommendations based on a single Class I study or consistent Class II studies.

Grade C: Recommendations based on a single Class II study.

Grade D: Recommendations based on Class III or weaker data, or based on inconsistent data.

Clinical Algorithm(s)

None provided

Evidence Supporting the Recommendations

Type of Evidence Supporting the Recommendations

The type of supporting evidence is identified and graded for each recommendation (see "Major Recommendations").

Benefits/Harms of Implementing the Guideline Recommendations

Potential Benefits

Appropriate treatment and management of patients with cervical spondylotic myelopathy

Potential Harms

Not stated

Qualifying Statements

Qualifying Statements
  • During guideline development, the group commonly encountered unsophisticated or poorly designed comparative methods in clinical trials. The most common flaw was the lack of a control group or the utilization of historical controls. Other common flaws were invalid outcome measures, and the lack either of randomization or blinding of outcome assessors. Specific examples are provided in the text of each topic. At the conclusion of each chapter of the original guideline document are suggestions for future areas of study and ideas to improve the quality of clinical research.
  • With each recommendation comes the risk of conformational bias. The recommendation of a therapeutic option presumes that functional and economic preferences have been determined. Reliable and valid outcome measures help in this respect. It is hoped that such functional and economic outcome measures represent the values important to the patient and society and less the practitioner. By focusing attention on outcome measures in each study, the values of the patient and society are represented in these guidelines.
  • To minimize any specialty bias, spinal surgeons from both orthopedic and neurosurgery departments participated in the creation of these guidelines. However, although invited, nonsurgical stakeholders did not participate—a circumstance that some might argue would predispose to conformational bias toward strong surgical recommendations. It is hoped in the future that nonsurgical stakeholders will participate. During this process, the entire group made a concerted effort to be unprejudiced. Many authors acknowledged that poor quality or controversial data often formed the basis of their predetermined ideas regarding standard treatment. It is expected that certain practitioners may disagree with the recommendations. However, with careful review of the scientific foundation, the critically thoughtful reader should find the recommendations warranted.

Implementation of the Guideline

Description of Implementation Strategy

An implementation strategy was not provided.

Institute of Medicine (IOM) National Healthcare Quality Report Categories

IOM Care Need
Getting Better
Living with Illness
IOM Domain
Effectiveness
Patient-centeredness

Identifying Information and Availability

Bibliographic Source(s)
Matz PG, Anderson PA, Holly LT, Groff MW, Heary RF, Kaiser MG, Mummaneni PV, Ryken TC, Choudhri TF, Vresilovic EJ, Resnick DK, Joint Section on Disorders of the Spine and Peripheral Nerves [trunc]. The natural history of cervical spondylotic myelopathy. J Neurosurg Spine. 2009 Aug;11(2):104-11. [20 references] PubMed External Web Site Policy
Adaptation

Not applicable: The guideline was not adapted from another source.

Date Released
2009 Aug
Guideline Developer(s)
American Association of Neurological Surgeons - Medical Specialty Society
Congress of Neurological Surgeons - Professional Association
Source(s) of Funding

Administrative costs of this project were funded by the Joint Section on Disorders of the Spine and Peripheral Nerves of the American Association of Neurological Surgeons and Congress of Neurological Surgeons.

Guideline Committee

Joint Section on Disorders of the Spine and Peripheral Nerves of the American Association of Neurological Surgeons and Congress of Neurological Surgeons Expert Group

Composition of Group That Authored the Guideline

Authors: Paul G. Matz, M.D., Division of Neurological Surgery, University of Alabama, Birmingham, Alabama; Paul A. Anderson, M.D., Department of Orthopedic Surgery, University of Wisconsin, Madison, Wisconsin; Michael G. Kaiser, M.D., Department of Neurological Surgery, Neurological Institute, Columbia University, New York, New York; Langston T. Holly, M.D., Division of Neurosurgery, David Geffen School of Medicine, University of California at Los Angeles, California; Michael W. Groff, M.D., Department of Neurosurgery, Harvard Medical School and Beth Israel Deaconess Medical Center, Boston, Massachusetts; Robert F. Heary, M.D., Department of Neurosurgery, University of Medicine and Dentistry of New Jersey—New Jersey Medical School, Newark, New Jersey; Praveen V. Mummaneni, M.D., Department of Neurosurgery, University of California at San Francisco, California; Timothy C. Ryken, M.D., Department of Neurosurgery, University of Iowa Hospitals and Clinics, Iowa City, Iowa; Tanvir F. Choudhri, M.D., Department of Neurosurgery, Mount Sinai School of Medicine, New York, New York; Edward J. Vresilovic, M.D., Ph.D., Department of Orthopedic Surgery, Milton S. Hershey Medical Center, Pennsylvania State College of Medicine, Hershey, Pennsylvania; Daniel K. Resnick, M.D., Department of Neurological Surgery, University of Wisconsin, Madison, Wisconsin

Financial Disclosures/Conflicts of Interest

No author received payment or honorarium for time devoted to this project. Dr. Resnick owns stock in Orthovita. Dr. Matz receives support from the Kyphon Grant for Thoracolumbar Fracture Study, and an advisory honorarium from Synthes for the cadaver laboratory. Dr. Heary receives support from DePuy Spine and Biomet Spine, and receives royalties from DePuy Spine and Zimmer Spine. Dr. Groff is a consultant for DePuy Spine. Dr. Mummaneni is a consultant for and receives university grants from DePuy Spine and Medtronic, Inc., and is a patent holder in DePuy Spine. Dr. Anderson is an owner of, consultant for, and stockholder of Pioneer Surgical Technology; a consultant for and receives non–study related support from Medtronic, Inc.; and is a patent holder in Stryker. The authors report no other conflicts of interest concerning the materials or methods used in this study or the findings specified in this paper.

Guideline Status

This is the current release of the guideline.

Guideline Availability

Electronic copies: Available from the Journal of Neurosurgery Web site External Web Site Policy.

Print copies: Available from the Journal of Neurosurgery Publishing Group, 1224 Jefferson Park Avenue, Suite 450, Charlottesville, Virginia 22903, USA. Telephone: 434-924-5503

Availability of Companion Documents

The following is available:

  • Introduction and methodology: guidelines for the surgical management of cervical degenerative disease. J Neurosurg Spine. 2009 Aug;11(2):101-3. Electronic copies: Available from the Journal of Neurosurgery Web site External Web Site Policy.
Patient Resources

None available

NGC Status

This NGC summary was completed by ECRI Institute on February 10, 2011. The information was verified by the guideline developer on March 20, 2011.

Copyright Statement

This NGC summary is based on the original guideline, which is subject to the guideline developer's copyright restrictions.

Disclaimer

NGC Disclaimer

The National Guideline Clearinghouse™ (NGC) does not develop, produce, approve, or endorse the guidelines represented on this site.

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