Systematic review of cohort studies comparing surgical treatments for cervical spondylotic myelopathy.

STUDY DESIGN: Systematic review of cohort studies comparing surgical treatment options for cervical spondylotic myelopathy. OBJECTIVE: Compare results of major surgical treatments. SUMMARY OF BACKGROUND DATA: Controversy exists between various surgical options for the treatment of multilevel cervical spondylotic myelopathy, including multilevel corpectomy (CORP) and fusion, anterior cervical discectomy and fusion, laminoplasty (LAMP), and laminectomy and fusion (LAMI). A systematic review was done in order to compare results and complications among these procedures. METHODS: Systematic review of retrospective cohort studies comparing anterior cervical discectomy and fusion (ACDF), CORP, LAMP, and LAMI from 1980 to January 2008. Separately, a review was performed of case series with greater than 10-year follow-up. RESULTS: About 1735 articles found initially, 591 abstracts screened, 36 articles retrieved in full, 11 studies included in review. All comparison studies are retrospective cohort studies. Four studies compared multilevel CORP versus LAMP, 1 study compared LAMI with LAMP, and 2 studies compared ACDF with LAMP. There were 3 case studies with greater than 10-year follow-up. CONCLUSION: All approaches yield similar neuro recovery rates. Laminoplasty has a significant incidence of neck pain compared with multilevel CORP. ACDFs increase the rate of adjacent secondary spondylosis compared with LAMP. Multilevel CORP and laminectomy with fusion have a significantly higher rate of graft, instrumentation, and approach related complications. Multilevel CORP and laminectomy with fusion have a significant decrease in range of motion of neck compared with LAMP.

Commercially funded and United States-based research is more likely to be published; good-quality studies with negative outcomes are not.

BACKGROUND: Prior studies implying associations between receipt of commercial funding and positive (significant and/or pro-industry) research outcomes have analyzed only published papers, which is an insufficiently robust approach for assessing publication bias. In this study, we tested the following hypotheses regarding orthopaedic manuscripts submitted for review: (1) nonscientific variables, including receipt of commercial funding, affect the likelihood that a peer-reviewed submission will conclude with a report of a positive study outcome, and (2) positive outcomes and other, nonscientific variables are associated with acceptance for publication. METHODS: All manuscripts about hip or knee arthroplasty that were submitted to The Journal of Bone and Joint Surgery, American Volume, over seventeen months were evaluated to determine the study design, quality, and outcome. Analyses were carried out to identify associations between scientific factors (sample size, study quality, and level of evidence) and study outcome as well as between non-scientific factors (funding source and country of origin) and study outcome. Analyses were also performed to determine whether outcome, scientific factors, or nonscientific variables were associated with acceptance for publication. RESULTS: Two hundred and nine manuscripts were reviewed. Commercial funding was not found to be associated with a positive study outcome (p = 0.668). Studies with a positive outcome were no more likely to be published than were those with a negative outcome (p = 0.410). Studies with a negative outcome were of higher quality (p = 0.003) and included larger sample sizes (p = 0.05). Commercially funded (p = 0.027) and United States-based (p = 0.020) studies were more likely to be published, even though those studies were not associated with higher quality, larger sample sizes, or lower levels of evidence (p = 0.24 to 0.79). CONCLUSIONS: Commercially funded studies submitted for review were not more likely to conclude with a positive outcome than were nonfunded studies, and studies with a positive outcome were no more likely to be published than were studies with a negative outcome. These findings contradict those of most previous analyses of published (rather than submitted) research. Commercial funding and the country of origin predict publication following peer review beyond what would be expected on the basis of study quality. Studies with a negative outcome, although seemingly superior in quality, fared no better than studies with a positive outcome in the peer-review process; this may result in inflation of apparent treatment effects when the published literature is subjected to meta-analysis.

Industry-funded positive studies not associated with better design or larger size.

Previous studies have associated commercial funding with positive outcomes in orthopaedic research. Those reports, however, failed to account for potential confounding variables that can lead to a disproportion of positive outcomes, including sample size, study design, and study quality. We tested the hypothesis that nonscientific factors (funding source, orthopaedic subspecialty, and geographic region of origin) are associated with positive study outcomes, but not the result of differences in study design, study quality, or sample size. All 747 abstracts presented at the 2004 American Academy of Orthopaedic Surgeons annual meeting underwent blinded analysis using previously published criteria. Studies that received commercial funding were more likely to conclude with positive outcomes. Subspecialty and country of origin were not associated with positive outcomes. Commercially funded studies were not more likely than non-funded studies to be well-designed. When control groups were used, those in commercially funded studies were not larger than those used in nonfunded studies. Our data suggest commercial funding was associated with positive outcomes, but we found no evidence to suggest commercially funded studies were better designed or larger than non-funded studies.