title: Diagnostic value of the nerve root sedimentation sign, a radiological sign using magnetic resonance imaging, for detecting lumbar spinal stenosis: a meta-analysis.
abstract: OBJECTIVE
  This study aimed to determine the diagnostic value of the nerve root sedimentation sign, a relatively new radiological sign using magnetic resonance imaging, for diagnosing lumbar spinal stenosis.
  
  
  METHODS
  The literature search was based on PUBMED, EMBASE, Cochrane Library, Google Scholar, and the Chinese Biomedical Literature Database up to March 2014. A total of 120 articles were identified. Seven studies involving 1,182 patients were included.
  
  
  RESULTS
  The quality of the methodology of the seven studies was good. Overall, the pooled weighted value showed that the sedimentation sign had moderate sensitivity of 0.80 [95 % confidence interval (CI) 0.77-0.83] and high specificity of 0.96 (95 % CI 0.94-0.98). The area under the curve was 0.76. Subgroup analysis showed that the degree of morphological spinal stenosis was responsible for the heterogeneity. In the patients with severe morphological lumbar spinal stenosis, the sedimentation sign had even higher sensitivity and specificity: 0.899 (95 % CI 0.87-0.92) and 0.99 (95 % CI 0.98-1.00), respectively. The area under the curve was 0.96. In the patients with lumbar spinal stenosis without definition of morphological stenosis, there was a notable threshold effect and significant heterogeneity. The area under the curve was 0.63.
  
  
  CONCLUSIONS
  Current evidence suggests that the sedimentation sign has high sensitivity and specificity for diagnosing severe lumbar spinal stenosis. Its performance in diagnosing moderate and mild spinal stenosis, however, has yet to be corroborated in properly designed studies.
authors.affiliation: Department of Spine Surgery, the Third Affiliated Hospital, Sun Yat-Sen University, No. 600 Tianhe Road, Guangzhou, 510630, China.
authors.forename: Liangming
authors.initials: L
authors.lastname: Zhang
authors.forename: Ruiqiang
authors.initials: R
authors.lastname: Chen
authors.forename: Peigen
authors.initials: P
authors.lastname: Xie
authors.forename: Wei
authors.initials: W
authors.lastname: Zhang
authors.forename: Yang
authors.initials: Y
authors.lastname: Yang
authors.forename: Limin
authors.initials: L
authors.lastname: Rong
mesh_terms: D006801:Humans; D008159:Lumbar Vertebrae / Q000473:pathology*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D012680:Sensitivity and Specificity; D013126:Spinal Nerve Roots / Q000473:pathology*; D013130:Spinal Stenosis / Q000473:pathology*