Use and misuse of the sedimentation sign in lumbar spine stenosis

The nerve root sedimentation sign (SedSign), introduced in 2010, is a radiological marker for lumbar spinal stenosis (LSS) on MRI. Despite widespread adoption, methodological inconsistencies in its application across studies have raised concerns about validity. This systematic review evaluated the accuracy of SedSign definitions and their impact on conclusions in published research.

PubMed and Google Scholar were searched for articles utilising the SedSign. Definitions and illustrations were independently assessed by two authors against Barz et al.'s original criteria, classified as accurate, inaccurate, or absent. Study conclusions regarding SedSign's clinical and radiological utility were categorised as positive or negative. Journal metrics were analysed for correlation with reported accuracy.

Only 14 out of 31 studies applied the SedSign definition correctly. Of the 21 studies endorsing its utility, 10 used inaccurate definitions. Notably, 3 of 5 studies dismissing its value also misapplied the criteria. Inaccurate reporting showed no significant association with journal metrics.

Frequent misapplication of the SedSign in the literature may impact the reliability of research on lumbar spinal stenosis-even in high-impact journals. These findings expose a critical need for stricter adherence to validated radiological criteria and more vigilant peer review. Professional societies may play a key role in the future by developing comprehensive open-access guidelines to support researchers and reviewers in the standardized application of gradings and classifications, thereby enhancing consistency across studies. Ensuring methodological rigour is essential to minimise misleading conclusions with potential clinical implications.