Abstract
Study Design
Meta-research.
Objectives
To evaluate the prevalence and types of severe spin and the methodological quality of systematic reviews addressing early versus delayed surgical decompression for central cord syndrome (CCS).
Methods
PubMed, Web of Science, Scopus, and Embase were searched for systematic reviews evaluating decompression timing in CCS. Two reviewers independently assessed studies for the nine most severe spin types and graded methodological quality using AMSTAR-2. Early decompression was designated as the experimental intervention, while conclusion direction was recorded separately from spin classification.
Results
Ten reviews met inclusion criteria. Spin was identified in 40% (4/10) of reviews, and all spin-positive reviews contained type 1 spin (clinical recommendations not supported by the review findings). Types 3 and 9 each occurred in 20% (2/10), while types 5, 7, and 8 were each present in 10% (1/10). Overall, six reviews favored early decompression, three had mixed or subgroup-dependent conclusions, and one reported no timing benefit. Nine reviews (90%) were rated critically low and one (10%) low by AMSTAR-2. Interrater agreement for the presence of any spin was substantial (κ = 0.783).
Conclusion
Severe spin was present in 40% of reviews, most commonly as clinical recommendations judged to extend beyond the supporting findings. These findings identify potential mismatches between recommendation strength and supporting evidence but do not establish that early decompression is ineffective or that spin explains the direction of the literature. Future reviews should align recommendation strength with risk of bias and certainty of evidence.