Quantification of Walking Ability in Participants with Neurogenic Claudication from Lumbar Spinal Stenosis – A Comparative Study

Background Context: Walking limitations caused by neurogenic claudication (NC) are typically assessed with self-reported measures, though objective evaluation of walking utilizing motorized treadmill test (MTT) or self-paced walking tests (SPWT) have periodically appeared in the lumbar spinal stenosis (LSS) literature. Purpose: This study compared the validity and responsiveness of MTT and SPWT for assessing walking ability before and after common treatments for NC. Study Design: Prospective, observational cohort study Patient Sample: 50 adults were recruited from an urban spine center if they had LSS, substantial walking limitations from NC, and were scheduled to undergo surgery (20%) or conservative treatment (80%). Outcome Measures: Walking times, distances and speeds along with characteristics of NC symptoms were recorded for MTT and SPWT. Self-reported measures included back and leg pain intensity assessed with 0 – 10 numeric pain scale, disability assessed with Oswestry Disability Index (ODI), walking ability assessed with estimated walking times and distances, and subscales from the Spinal Stenosis Questionnaires (SSQ). Methods: MTT used a level track, and SPWT were conducted in a rectangular hallway. Walking speeds were self-selected and test endpoints were: a) NC, b) fatigue, or c) completed the 30-minute test protocol. Results from MTT and SPWT were compared with each other and with self-reported measures. Internal responsiveness was assessed by comparing changes in initial to post-treatments results, and external responsiveness by comparing walking test results between those that improved with those that did not improve by self-report criteria. Results: Mean age was 68 years. 58% were male. NC included leg pain (88%), and buttock(s) pain (12%). 5 participants could not safely perform MTT. Walking speeds were faster and distances were greater with SPWT, although results from both tests correlated with each other and with self-reported measures. 72% of participants reported improvement following treatment which was confirmed by significant mean differences in self-reported measures. MTT results did not demonstrate internal responsiveness to change in clinical status following treatment, but SPWT did with increased mean walking times (6 min) and distances (387 m). When responsiveness was assessed against external criterion, both SPWT and MTT demonstrated substantial divergence with self-reported changes in clinical status and alternative outcome measures. Conclusions: Both MTT and SPWT can quantify walking abilities in NC. As outcome tools, SPWT demonstrated better internal responsive than MTT, but neither test demonstrated external responsiveness. Neither test should be considered as a meaningful substitution for disease specific measures of function.