Lumbar spine segmental mobility assessment: An examination of validity for determining intervention strategies in patients with low back pain

Objective: To examine the predictive validity of posterior-anterior (PA) mobility testing in a group of patients with low back pain (LBP). Design: Randomized controlled trial. Setting: Outpatient physical therapy clinics. Participants: Patients with LBP (N=131; mean age +/- standard deviation, 33.9 +/- 10.9y; range, 19-59y), and a median symptom duration of 27 days (range, 1-5941d). Patients completed a baseline examination, including PA mobility testing, and were categorized with respect to both hypomobility and hypermobility (present or absent), and treated for 4 weeks. Intervention: Seventy patients were randomized to an intervention involving manipulation and 61 to a stabilization exercise intervention. Main Outcome Measures: Oswestry Disability Questionnaire (ODQ) scores were collected at baseline and after 4 weeks. Three-way repeated measures analyses of variance (ANOVAs) were performed to assess the effect of mobility categorization and intervention group on the change on the ODQ with time. Number-needed-to-treat (NNT) statistics were calculated. Results: Ninety-three (71.0%) patients were judged to have hypomobility present and 15 (11.5%) were judged with hypermobility present. The ANOVAs resulted in significant interaction effects. Pairwise comparisons showed greater improvements among patients receiving manipulation categorized with hypomobility present versus absent (mean difference, 23.7%; 95% confidence interval [CI], 5.1%-42.4%), and among patients receiving stabilization categorized with hypermobility present versus absent (mean difference, 36.4%; 95% CI, 10.3%-69.3%). For patients with hypomobility, failure rates were 26% with manipulation and 74.4% with stabilization (NNT=2.1; 95% CI, 1.6-3.5). For patients with hypermobility, failure rates were 83.3% and 22.2% for manipulation and stabilization, respectively (NNT=1.6; 95% CI, 1.2-10.2). Conclusions: Patients with LBP judged to have lumbar hypomobility experienced greater benefit from an intervention including manipulation; those judged to have hypermobility were more likely to benefit from a stabilization exercise program.