Decompression surgery improves gait quality in patients with symptomatic lumbar spinal stenosis

Background context: We aimed to fully understand the extent of limitations associated with symptomatic lumbar spinal stenosis (LSS) and the functional outcome of its treatment, including not only function during daily activities (eg, using the 6-minute walk test [6MWT]) but also the quality of function that should be objectively assessed.

Purpose: This study was performed to test the hypothesis that the Oswestry Disability Index (ODI) score, the walking distance during the 6MWT (6-minute walking distance [6MWD]), and gait quality (spatiotemporal parameters and gait asymmetry) will improve postoperatively and achieve normal values; to determine if changes in gait parameters correlate with changes in Oswestry Disability Index (ODI) score; and to ascertain if patients' gait quality will diminish during the 6MWT, reflected by changes in gait parameters during the 6MWT.

Study design/setting: This is a prospective observational study with intervention.

Patient sample: The sample comprised patients with symptomatic LSS.

Outcome measures: The ODI score, gait quality (spatiotemporal and asymmetry), and walking performance (walking distance during the 6MWT) were the outcome measures.

Methods: Patients with symptomatic LSS were analyzed on the day before surgery and 10 weeks and 12 months postoperatively. Functional disability in daily life was assessed by the ODI. Spatiotemporal and kinematic gait parameters were recorded with an inertial sensor system during the 6MWT, and the 6MWD was determined. Gait asymmetry was defined as 100*|right-left|/(0.5*(|right+left|)).

Results: The ODI decreased by 17.9% and 23.9% and 6MWD increased by 21 m and 26 m from baseline to 10-week and 12-month follow-up, respectively. Gait quality did not change during the 6MWT at any assessment or between assessments. Compared with the control group, patients walked less during the 6MWT, and gait quality differed between patients and the control group at baseline and 10-week follow-up but not at 12-month follow-up. Change in gait quality explained 39% and 73% of variance in change in ODI from baseline to 10-week and to 12-month follow-up, respectively.

Conclusions: Changes in gait quality explained a large portion of variance in changes in the ODI, indicating that patients with symptomatic LSS perceive their compromised gait quality as functional limitations. Gait data obtained by instrumented gait analysis contain information on gait quality that can be helpful for evaluating functional limitations in patients with LSS, the outcome of decompression surgery, and the development of patient-specific rehabilitation regimens.