Associations between physical therapy and long-term outcomes for individuals with lumbar spinal stenosis in the SPORT study

Abstract

Background context: A period of nonsurgical management is advocated before surgical treatment for most patients with lumbar spinal stenosis. Currently, little evidence is available to define optimal nonsurgical management. Physical therapy is often used, however its use and effectiveness relative to other nonsurgical strategies has not been adequately explored.

Purpose: Describe the use of physical therapy and other nonsurgical interventions by patients with lumbar spinal stenosis and examine the relationship between physical therapy and long-term prognosis.

Study design: Secondary analysis of the Spine Patient Outcomes Research Trial (SPORT) combining data from randomized and observational studies.

Setting: Thirteen spine clinics in 11 states in the United States.

Patient sample: Patients with lumbar spinal stenosis receiving nonsurgical management including those who did or did not receive physical therapy within 6 weeks of enrollment.

Outcome measures: Primary outcome measures included crossover to surgery, the bodily pain and physical function scales changes from the Survey Short Form 36 (SF-36), and the modified Oswestry Disability Index. Secondary outcome measures were patient satisfaction and the Sciatica Bothersomeness Index.

Methods: Baseline characteristics and rates of crossover to surgery were compared between patients who did or did not receive physical therapy. Baseline factors predictive of receiving physical therapy were examined with logistic regression. Mixed effects models were used to compare outcomes between groups at 3 and 6 months and 1 year after enrollment adjusted for baseline severity and patient characteristics.

Results: Physical therapy was used in the first 6 weeks by 90 of 244 patients (37%) and was predicted by the absence of radiating pain and being single instead of married. Physical therapy was associated with a reduced likelihood of crossover to surgery after 1 year (21% vs. 33%, p=.045), and greater reductions on the Short Form 36 physical functioning scale after 6 months (mean difference=6.0, 95% confidence interval: 0.2-11.7) and 1 year (mean difference=6.5, 95% confidence interval: 0.6-12.4). There were no differences in bodily pain or Oswestry scores across time.

Conclusions: Many patients with lumbar spinal stenosis pursuing conservative management receive physical therapy. Using physical therapy was associated with reduced likelihood of patients receiving surgery within 1 year. Results for other outcomes were mixed with no differences in several measures. Further research is needed to examine the effectiveness of physical therapy relative to other nonsurgical management strategies for patients with lumbar spinal stenosis.

Keywords: Exercise; Lumbar spinal stenosis; Physical therapy; Prognosis; Rehabilitation; Surgery.

Figure 1

Screening, Exclusion, Enrollment, Randomization and Follow-up of SPORT patients included in the analysis of the impact on outcomes of physical therapy in the first six weeks of SPORT enrollment.

Figure 2

Primary outcomes for patients who received or did not receive physical therapy during the first six weeks after enrollment during 1 year of follow-up. Graphs show adjusted mean change from baseline. Bodily pain and physical function scores from the SF-36 range from 0–100 with higher scores indicating less severe symptoms. The Oswestry index ranges from 0–100 with lower scores indicating less disability. Horizontal bars represent 95% confidence intervals. P-values are time-weighted average 1-year area under curve p-values.

Figure 3

Secondary outcomes for patients who received or did not receive physical therapy during the first six weeks after enrollment during 1 year of follow-up. Graphs show adjusted mean percentages for each outcome. Horizontal bars represent 95% confidence intervals. P-values are time-weighted average 1-year area under curve p-values.