title: Relationship between sedimentation sign and morphological grade in symptomatic lumbar spinal stenosis.
abstract: OBJECTIVE
  We aimed to study the relationship between two morphological parameters recently described on MRI images in relation to lumbar spinal stenosis (LSS): the first is the sedimentation sign (SedS) and the second is the morphological grading of lumbar stenosis.
  
  
  METHODS
  MRIs from a total of 137 patients were studied. From those, 110 were issued from a prospective database of symptomatic LSS patients, of whom 73 were treated surgically and 37 conservatively based on symptom severity. A third group consisting of 27 subjects complaining of low back pain (LBP) served as control. Severity of stenosis was judged at disc level using the four A to D grade morphological classification. The presence of a SedS was judged at pedicle level, above or below the site of maximal stenosis.
  
  
  RESULTS
  A positive SedS was observed in 58, 69 and 76% of patients demonstrating B, C and D morphology, respectively, but in none with grade A morphology. The SedS was positive in 67 and 35% of the surgically and conservatively treated patients, respectively, and in 8% of the LBP group. C and D morphological grades were present in 97 and 35% of patients in the surgically and conservatively treated group, respectively, and in 18% of the LBP group. Presence of a positive SedS carried an increased risk of being submitted to surgery in the symptomatic LSS group (OR 3.5). This risk was even higher in the LSS patients demonstrating grade C or D morphology (OR 65).
  
  
  CONCLUSIONS
  One-third of surgically treated LSS patients do not present a SedS. This sign appears to be a lesser predictor of treatment modality in our setting of symptomatic LSS patients compared to the severity of stenosis judged by the morphological grade.
authors.affiliation: Department of Orthopedics, Centre Hospitalier Universitaire Vaudois, University of Lausanne, Avenue Pierre-Decker 4, Lausanne, Switzerland.
authors.forename: P A
authors.initials: PA
authors.lastname: Laudato
authors.affiliation: Department of Orthopedics, Centre Hospitalier Universitaire Vaudois, University of Lausanne, Avenue Pierre-Decker 4, Lausanne, Switzerland.
authors.forename: G
authors.initials: G
authors.lastname: Kulik
authors.affiliation: Neuro-Orthopaedic Spine Unit, Hirslanden Group of Private Hospitals, Clinique Cecil, Lausanne, Switzerland. cschizas@hotmail.com.
authors.forename: C
authors.initials: C
authors.lastname: Schizas
mesh_terms: D006801:Humans; D008159:Lumbar Vertebrae / Q000503:physiopathology*; D008279:Magnetic Resonance Imaging; D011446:Prospective Studies; D013130:Spinal Stenosis / Q000145:classification / Q000175:diagnosis / Q000453:epidemiology / Q000503:physiopathology
keywords: Classification; Imaging studies; Lumbar spinal stenosis; Morphological stenosis grade; Sedimentation sign