WALKING DISTANCE AS A MEASURE OF DISABILITY IN LUMBAR SPINAL STENOSIS

Abstract

Since neurological claudication is a major symptom in lumbar spinal stenosis (LSS), walking distance is commonly used as a measure of the severity and surgical outcome in LSS. The aim of this study was to compare self-reported and treadmill-measured walking distances in a trial, in which 94 patients with moderate LSS had been randomized into conservative and surgical treatment. Among the 44 patients in conservative treatment, the treadmill-measured walking distance was more reproducible after 6 months than the self-reported distance; the intraclass correlation coefficients were 0.75 and 0.41, respectively. Among all the patients at baseline, the agreement between self-reported and measured walking distance was satisfactory (intraclass correlation 0.57), although male patients overwhelmed their performance by 200 meters. Such a shift was not found in women. For walking distance categorized as < 400, 400–1249 and ≥ 1250 meters, there was a fair agreement between self-report and treadmill (weighed kappa 0.42). However, when the analysis was restricted to those whose walking distance was restricted to < 1250 meters, the corresponding agreement was poor (intraclass correlation 0.26). The self-reported walking distance was closely correlated with Oswestry index at baseline (r = 0.26), and changes in these outcomes from randomization to the follow-up of 6 months showed a strong correlation with each other (r = 0.37). We conclude that walking distance is a fundamental element of disability in LSS. Self-reported walking distance seems to be an appropriate clinical tool, but its limited precision in relation to treadmill-measured distance must be considered, when walking ability is severely restricted.