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Guideline Summary
Guideline Title
Techniques for cervical interbody grafting.
Bibliographic Source(s)
Ryken TC, Heary RF, Matz PG, Anderson PA, Groff MW, Holly LT, Kaiser MG, Mummaneni PV, Choudhri TF, Vresilovic EJ, Resnick DK, Joint Section on Disorders of the Spine and Peripheral Nerves [trunc]. Techniques for cervical interbody grafting. J Neurosurg Spine. 2009 Aug;11(2):203-20. [44 references] PubMed External Web Site Policy
Guideline Status

This is the current release of the guideline.

Scope

Disease/Condition(s)

Cervical radiculopathy or myelopathy secondary to degenerative disease

Guideline Category
Treatment
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 determine the efficacy of interbody graft techniques
Target Population

Patients undergoing ventral surgery for cervical degenerative disease

Interventions and Practices Considered

Interbody Grafting Techniques

  1. Autograft bone harvested from the iliac crest
  2. Allograft bone from either cadaveric iliac crest or fibula
  3. Titanium cages and rectangular fusion devices, with or without autologous graft or substitute
  4. Polyetheretherketone (PEEK) cages
  5. Carbon fiber cage (CFCs)
  6. Polymethyl-methyl methacrylate (PMMA)
  7. Recombinant human bone morphogenic protein-2 (rhBMP-2) (considered but not recommended routinely)
Major Outcomes Considered
  • Fusion rate
  • Clinical outcome (relief of arm and neck pain)
  • Neck and arm pain
  • Graft collapse rate
  • Complication rate

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 group searched the National Library of Medicine (PubMed) and the Cochrane Database for the period from 1966 through 2007 using the MeSH subject headings of cervical and fusion (4,231 references) and cervical and arthrodesis (2,347 references). After combining the databases and eliminating duplicates, 5,237 articles remained. The group reviewed the titles and abstracts with attention to those titles addressing issues pertinent to obtaining fusion in the cervical spine. The group also considered secondary outcomes of interest, including graft site morbidity, effect of smoking, number of levels included, and the role of surgical adjuncts if sufficient information were presented to warrant review. The bibliographies of the selected papers were also reviewed for additional references of relevance.

The group selected articles if they addressed issues related to cervical spine surgery, arthrodesis, and interbody grafting. They excluded articles that did not contain information regarding arthrodesis rates and/or outcomes and gave preference to articles that contained randomized or prospective data. Articles primarily included data on anterior approaches with a paucity of studies examining posterior fusion. The group compiled evidentiary tables (See Tables 1–4 in the original guideline document) based on the resulting list of 43 studies selected for inclusion. In general, these studies addressed different types of grafting media including autograft, allograft, and xenograft, and a multitude of different interbody prostheses. Four systematic reviews were identified. The remainder of the studies selected for inclusion were randomized trials, prospective cohort studies, or large case series reports.

Number of Source Documents

43 studies were selected for inclusion in the evidentiary tables.

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

Indications

1- or 2-Level Cervical Discectomy. Autograft bone harvested from iliac crest, allograft bone from either cadaveric iliac crest or fibula, or titanium cages and rectangular fusion devices, with or without autologous graft or substitute, are recommended for use in creating an arthrodesis after 1- or 2-level anterior cervical discectomy with fusion (ACDF) (Quality of evidence, Class II; Strength of recommendation, C).

Technique

Autograft, Allograft, or Titanium Cage. Autograft bone harvested from the iliac crest, allograft bone from either cadaveric iliac crest or fibula, or titanium cages and rectangular fusion devices, with or without autologous graft or substitute, are recommended for creating an arthrodesis after 1- or 2-level ACDF (Quality of evidence, Class II; Strength of recommendation, C).

Polyetheretherketone (PEEK) Cages, Carbon Fiber Cages (CFCs), Polymethyl-methyl methacrylate (PMMA), Recombinant Human Bone Morphogenic Protein-2 (rhBMP-2). If alternatives to autograft, allograft, or titanium cages are preferred, several options are recommended including PEEK cages, CFCs, PMMA, and rhBMP-2. PEEK cages may be considered with or without the use of hydroxyapatite for ACDF. Using hydroxyapatite alone may result in more settling and fragmentation (Quality of evidence, Class III; Strength of recommendation, D). CFCs are recommended for arthrodesis after ACDF with fusion rates >50% (Quality of evidence, Class III; Strength of recommendation, D).

The use of PMMA is not recommended as a means to preserve interspace height after anterior discectomy. Although short-term results are similar to those obtained with bone grafts, fusion generally does not occur when PMMA is used as a spacer, and the long-term consequences have not been described (Quality of evidence, Class II; Strength of recommendation, B).

Although rhBMP-2 promotes fusion with rates equivalent to autograft, its use in the cervical spine carries a complication rate of up to 23% to 27% (especially for local edema) compared with 3% for a standard approach. This significant difference prompted a public health notification by the U.S. Food and Drug Administration (FDA) (http://www.fda.gov/cdrh/safety/070108-rhbmp.html External Web Site Policy). Current evidence does not support the routine use of rh-BMP-2 for cervical arthrodesis. However, the use of rh-BMP-2 may have utility in the context of future studies in patients in whom cervical fusion poses a great technical challenge (Quality of evidence, Class II; Strength of recommendation, C).

Summary

Class II evidence indicates that either autograft bone harvested from iliac crest, allograft bone from either cadaveric iliac crest or fibula, or titanium cages and rectangular fusion devices, with or without autologous graft or substitute are excellent interbody treatment options for obtaining cervical arthrodesis. There is an expected autograft fusion rate for noninstrumented single-level fusions better than 80% and for 2-level fusion of better than 70%. With allograft, the expected fusion rate for noninstrumented single-level fusion is >80%, and is >50% for 2-level fusion. The use of titanium cages carries an expectation of a fusion rate of >70%, and often >90% with avoidance of donor site morbidity.

In choosing a graft strategy, no single type of graft has proven consistently superior to the other. Class III evidence suggests that the surgeon consider the increased rate of subsidence with allograft but also understand that subsidence does not correlate with clinical outcome. Class III evidence also suggests that the surgeon factor in the incidence of donor pain and decrease in patient satisfaction reported with the harvest of autograft iliac crest graft.

If alternatives to auto- and allograft are preferred, therapeutic options are as follows: PEEK may be considered with or without the use of hydroxyapatite after ACDF. There is an expectation of fusion rates >90% with fewer complications due to the absence of graft harvesting (Class III). CFCs may be considered as well with fusion rates ranging from 55% to 62% in the larger studies (Class III). PMMA may be considered to preserve intervertebral distraction after discectomy, but is a poor fusion substrate (Class II). All of the above options appear to have similar clinical outcomes equivalent to the use of bone.

Utilization of rhBMP-2 may be considered as an adjunct to promote fusion with rates equivalent to autograft. However, the high complication rate argues against its routine use for cervical arthrodesis. The surgeon must be aware that this use of rhBMP-2 is currently off-label, and its use in the cervical spine carries a reported complication rate of up to 27% (for edema), compared with 3% for a standard approach. This significant difference prompted a public health notification by the FDA (http://www.fda.gov/cdrh/safety/070108-rhbmp.html External Web Site Policy).

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 use of cervical interbody grafting techniques

Potential Harms
  • In general, allograft has a slower and less complete incorporation than autologous bone graft; however, the harvest of autograft from the anterior iliac crest, the fibula, or rib may be associated with significant postoperative complications. Factors that have been reported to have an impact on fusion rate include smoking, number of fusion levels, and the use of cervical instrumentation.
  • Allograft bone has been tried in a variety of applications, but also has potential limitations including cost, availability, infectious risks, and potentially lower fusion rates.
  • Recombinant human bone morphogenic protein-2 (rhBMP-2) carries a complication rate of up to 23% to 27% (especially for local edema) compared with 3% for a standard approach. This significant difference prompted a public health notification by the U.S. Food and Drug Administration (FDA).

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 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)
Ryken TC, Heary RF, Matz PG, Anderson PA, Groff MW, Holly LT, Kaiser MG, Mummaneni PV, Choudhri TF, Vresilovic EJ, Resnick DK, Joint Section on Disorders of the Spine and Peripheral Nerves [trunc]. Techniques for cervical interbody grafting. J Neurosurg Spine. 2009 Aug;11(2):203-20. [44 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

The 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: Timothy C. Ryken, M.D., Department of Neurosurgery, University of Iowa Hospitals and Clinics, Iowa City, Iowa; Robert F. Heary, M.D., Department of Neurosurgery, University of Medicine and Dentistry of New Jersey—New Jersey Medical School, Newark, New Jersey; 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 W. Groff, M.D., Department of Neurosurgery, Harvard Medical School and Beth Israel Deaconess Medical Center, Boston, Massachusetts; Langston T. Holly, M.D., Division of Neurosurgery, David Geffen School of Medicine, University of California at Los Angeles, California; Michael G. Kaiser, M.D., Department of Neurological Surgery, Neurological Institute, Columbia University, New York, New York; Praveen V. Mummaneni, M.D., Department of Neurosurgery, University of California at San Francisco, California; 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 summary was completed by ECRI Institute on February 15, 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

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

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