Sedimentation Sign Appraisal in Lumbar Spinal Stenosis

Abstract

BACKGROUND:Lumbar nerve roots normally sediment, due to gravity, to the dorsal part of the dural sac, which isknown as negative sedimentation sign. If there is a magnetic resonance finding of nerve roots inthe ventral part of the dural sac the sedimentation sign is positive.OBJECTIVE:To evaluate the presence of the MRI finding of positive sedimentation sign in patients clinicallysuspected to have lumbar spinal stenosis and if this sign can be a valid tool to differentiatesymptomatic spinal canal stenosis from other causes of non-specific back pain.METHODS:A planned cohort design prospective study had conducted over a year through July 2019 atthe department of neurosurgery at Medical City / Baghdad / Iraq. The study incorporates 200 patients.Those with symptomatic lumbar spine canal stenosis (n=100) show claudication with or without lowback pain, leg pain, a dural sac cross-sectional area < 80 mm2, and a walking interval < 200 meters.The nonspecific low back pain group (n=100) had no leg pain, no claudication, a cross-sectional areaof the dural sac >120 mm2, and a walking interval >1000 meters. The frequency of a positivesedimentation sign compared between both groups to evaluate if this sign can be a valid tool todifferentiate spinal canal stenosis from other causes of back pain, intra-rater and inter-rater assessmentdependability in a stochastic subsample executed.RESULTS:A positive sedimentation sign recognized in 96 patients in the symptomatic lumbar spine canalstenosis group (96%; 95% Confidence Interval CI, 90%–98%), no positive sedimentation signrecognized in the nonspecific low back pain group (0%; 95% Confidence Interval CI, 0%–5%).Credibility was Kappa (ĸ) =1.0 (intra-rater) and Kappa (ĸ) =0.90 (inter-rater), in sequence.CONCLUSION:A positive sedimentation sign is dependably seen in lumbar spine canal stenosis cases, recommendingits value in clinical application.