title: The validity of a clinical test for the diagnosis of lumbar spinal stenosis.
abstract: BACKGROUND
  The diagnosis and management of acquired lumbar spinal stenosis (ALSS) is an area of growing interest with an increase in its prevalence and detection in the older population.
  
  
  OBJECTIVE
  To investigate the diagnostic accuracy of a modified extension test (MExT) for diagnosing ALSS in subjects aged fifty or over.
  
  
  METHODS
  Symptomatic response of the bi-component MExT was evaluated and compared against magnetic resonance imaging (MRI) findings in 30 subjects. Estimates of sensitivity, specificity, likelihood ratios (LRs) and post-test probabilities were all calculated, and the capability of the test to discriminate between grade and location of stenosis was also appraised.
  
  
  RESULTS
  MExT sensitivity was high at 92% (95% confidence intervals (CI), 72-99%) leading to a significant negative likelihood ratio at -LR 0.2 (95% CI, 0.03-1.36); conversely, specificity was low at 40% (95% CI, 7-82%) with only a small positive likelihood ratio of +LR 1.53 (95% CI, 0.74-3.16). All correlations between the MExT and concurrent grade, or location of stenosis appeared weak and insignificant.
  
  
  CONCLUSIONS
  The MExT was found to demonstrate acceptable criterion validity in relation to ruling-out a diagnosis when a negative result was observed; however, further validation appears warranted.
authors.affiliation: Physiotherapy Department, Chesterfield Royal Hospital, Chesterfield, Derbyshire, UK.
authors.forename: Robert
authors.initials: R
authors.lastname: Dobbs
authors.affiliation: 38 Collegiate Crescent, Faculty of Health and Wellbeing, Sheffield Hallam University, Sheffield S10 2BP, UK. Electronic address: s.may@shu.ac.uk.
authors.forename: Stephen
authors.initials: S
authors.lastname: May
authors.affiliation: Physiotherapy Department, Chesterfield Royal Hospital, Chesterfield, Derbyshire, UK.
authors.forename: Philip
authors.initials: P
authors.lastname: Hope
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D019937:Diagnostic Techniques and Procedures / Q000592:standards*; D005260:Female; D006801:Humans; D008159:Lumbar Vertebrae / Q000503:physiopathology*; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D015203:Reproducibility of Results; D013130:Spinal Stenosis / Q000175:diagnosis*
keywords: Diagnosis; Extension test; Lumbar; Spinal stenosis; Validity