Results of a study published in The Spine Journal indicate that the Oswestry Disability Index, Modified Swiss Spinal Stenosis Scale (SSS), and Patient Specific Functional Scale possess adequate psychometric properties to be used in the outcome assessment of patients with lumbar spinal stenosis. However, further investigation is needed to validate these findings in other samples of patients with lumbar spinal stenosis and nonspecific low back pain, the authors add.  

This cohort secondary analysis of a randomized clinical trial of patients with lumbar spinal stenosis receiving outpatient physical therapy included 55 patients (mean age, 69.5 years; standard deviation, ±7.9 years; 43.1% females).

Outcome measures were the Modified Oswestry Disability Index, SSS, Patient Specific Functional Scale, and Numeric Pain Rating Scale (NPRS).

All patients completed the Oswestry Disability Index, SSS, Patient Specific Functional Scale, and NPRS at the baseline examination and at a follow-up. In addition, patients completed a 15-point Global Rating of Change at follow-up, which was used to categorize whether patients experienced clinically meaningful change. Changes in the Oswestry Disability Index, SSS, Patient Specific Functional Scale, and NPRS were then used to assess test-retest reliability, responsiveness, and minimum levels of detectable and clinically important differences.

The Oswestry Disability Index was the only outcome measure to exhibit excellent test-retest reliability with an intraclass correlation coefficient of 0.86. All others ranged between fair and moderate. The Oswestry Disability Index, SSS, and Patient Specific Functional Scale exhibited varying levels of responsiveness, each of which was superior to the NPRS. The minimal clinically important difference for the outcome measures for persons with lumbar spinal stenosis were:

• Oswestry Disability Index—5 points
• SSS— 0.36 and 0.10 for symptoms subscale and functional subscale, respectively
• Patient Specific Functional Scale—1.3
• NPRS—1.25 for back/buttock symptoms, 1.5 for thigh/leg symptoms

APTA member Joshua A. Cleland, PT, PhD, OCS, is the article's lead author. APTA members Julie M. Whitman, PT, T, DSc, OCS, FAAOMPT, Robert S. Wainner, T, PhD, ECS, OCS, FAAOMPT, and John D. Childs, PT, PhD, MBA, are coauthors.