Spine Stabilisation Trial: Implementation of a multicentre randomised controlled trial

The reliability of the Shuttle Walking Test, the Swiss Spinal Stenosis Questionnaire, the Oxford Spinal Stenosis Score, and the Oswestry Disability Index in the assessment of patients with lumbar spinal stenosis

STUDY DESIGN

The Shuttle Walking Test (SWT), the Swiss Spinal Stenosis (SSS) Questionnaire, the Oxford Claudication Score (OCS), and the Oswestry Disability Index (ODI) were administered to patients with lumbar spinal stenosis and neurogenic claudication.

OBJECTIVE

To determine reliability of the SWT, the SSS (Q1-12), the OCS, and the ODI in lumbar spinal stenosis assessment.

SUMMARY OF BACKGROUND DATA

Reliability data for exercise tests in lumbar spinal stenosis are lacking.

METHODS

To determine reliability, 32 clinic patients with lumbar spinal stenosis were assessed twice, with 1 week between assessments. Retrospective data from 17 patients assessed before surgery and 18 months after surgery for lumbar spinal stenosis were used to investigate the use of reliability in a clinical setting.

RESULTS

Test-retest reliability in terms of the intraclass correlation coefficient (ICC) was 0.92 for the SWT, 0.92 for the SSS, 0.83 for the OCS and 0.89 for the ODI. The mean percentage scores were 51 for the SSS, 45 for the OCS, and 40 for the ODI. To achieve 95% certainty of change between assessments for a single patient, the SSS would need to change by 15, the OCS by 20, and the ODI by 16. The mean SWT was 150 m, with a change of 76 m required for 95% confidence. Cronbach's alpha was 0.91 for the SSS, 0.90 for the OCS, and 0.89 for the ODI. The change in ODI correlated most strongly with patient satisfaction after surgery (rho = 0.80; P < 0.001).

CONCLUSIONS

Fluctuations in a patient's symptoms result in wide individual confidence intervals. Performance on the SSS, OCS, and ODI questionnaires are broadly similar, the most precise being the condition-specific SSS. The SWT gives a snapshot of physical function, which is acceptable for group analysis. Use of the SWT for individual assessment after surgery is feasible.

The Oswestry Disability Index

STUDY DESIGN

The Oswestry Disability Index (ODI) has become one of the principal condition-specific outcome measures used in the management of spinal disorders. This review is based on publications using the ODI identified from the authors' personal databases, the Science Citation Index, and hand searches of Spine and current textbooks of spinal disorders.

OBJECTIVES

To review the versions of this instrument, document methods by which it has been validated, collate data from scores found in normal and back pain populations, provide curves for power calculations in studies using the ODI, and maintain the ODI as a gold standard outcome measure.

SUMMARY OF BACKGROUND DATA

It has now been 20 years since its original publication. More than 200 citations exist in the Science Citation Index. The authors have a large correspondence file relating to the ODI, that is cited in most of the large textbooks related to spinal disorders.

METHODS

All the published versions of the questionnaire were identified. A systematic review of this literature was made. The various reports of validation were collated and related to a version.

RESULTS

Four versions of the ODI are available in English and nine in other languages. Some published versions contain misprints, and many omit the scoring system. At least 114 studies contain usable data. These data provide both validation and standards for other users and indicate the power of the instrument for detecting change in sample populations.

CONCLUSIONS

The ODI remains a valid and vigorous measure and has been a worthwhile outcome measure. The process of using the ODI is reviewed and should be the subject of further research. The receiver operating characteristics should be explored in a population with higher self-report disabilities. The behavior of the instrument is incompletely understood, particularly in sensitivity to real change.