Abstract
Background. Neurogenic claudication is a well recognised symptom of spinal stenosis. Pain in the lower limbs and back limit walking speed and distance. Outcome of treatment should be easily measurable, but in practice is not. Walking tests are difficult to perform reliably. It is possible to measure speed and endurance with a treadmill, but this is expensive, of doubtful reliability, and many elderly patients are reasonably worried about falling off. Commonly used back pain outcome questionnaires are probably invalid for this population, and few questionnaires have been designed specifically for this complaint. The purpose of this study was to evaluate 3 questionnaires (Swiss Spinal Stenosis Score (SSS), Oxford Claudication Score (OCS) and Oswestry Disability Index (ODI)) and a Shuttle Walking Test (SWT). The Shuttle Walking Test, developed originally in respiratory medicine, shows promise as both a clinical measure and outcome measure for patients with neurogenic claudication. In an internal study, we have found that none of our patients selected for surgery can manage more than 200 metres. A fit adult can usually manage about 600 metres on this test.
Study Design: Shuttle Walking Test (SWT), Swiss Spinal Stenosis Score (SSS), Oxford Claudication Score (OCS) and Oswestry Disability Index (ODI) were administered to patients with lumbar spinal stenosis (LSS) and neurogenic claudication.
Objective: To determine reliability of SWT, SSS (Q1–12), OCS and ODI in LSS assessment.
Methods: Thirty two clinic patients with LSS were assessed twice with one week between assessments to determine reliability. Retrospective data from 17 patients assessed before and 18 months after surgery for LSS were used to investigate use of reliability in a clinical setting.
Results: Test-retest reliability was 0.92 for SWT, 0.92 for SSS, 0.83 for OCS and 0.89 for ODI (Intraclass correlation coefficient). Mean scores (percent) were SSS 51, OCS 45 and ODI 40. For 95% certainty of change between assessments for a single patient, SSS would need to change by 15, OCS by 20 and ODI by 16. Mean SWT was 150m, with change of 76m required for 95% confidence. Cronbach’s alpha was 0.91 for SSS, 0.90 for OCS and 0.89 for ODI. Change in ODI correlated most strongly with patient satisfaction after surgery (_=0.80, p< 0.001).
Conclusions: Fluctuations in patient’s symptoms result in wide individual confidence intervals. Performance of SSS, OCS and ODI questionnaires are broadly similar. The condition specific SSS is most precise but not much better than the non-specific ODI. SWT gives a snapshot of physical function which is acceptable for group analysis. Use of SWT for individual assessment after surgery is feasible but multiple testing would improve sensitivity for change.
The abstracts were prepared by Dr P Dolan. Correspondence should be addressed to him at the British Orthopaedic Association, Royal College of Surgeons, 35-43 Lincoln’s Inn Fields, London WC2A 3PN.
