Robert Dobbs1, Stephen May2, Philip Hope1. 1. Physiotherapy Department, Chesterfield Royal Hospital, Chesterfield, Derbyshire, UK. 2. 38 Collegiate Crescent, Faculty of Health and Wellbeing, Sheffield Hallam University, Sheffield S10 2BP, UK. Electronic address: s.may@shu.ac.uk.
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. OBJECTIVES: 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.
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. OBJECTIVES: 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: Christian Jaeger Cook; Chad E Cook; Michael P Reiman; Anand B Joshi; William Richardson; Alessandra N Garcia Journal: Eur Spine J Date: 2019-07-16 Impact factor: 3.134