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.

Aims: To clarify the effectiveness of surgical intervention (S) as compared to non-operative measures (NO) in the treatment of patients with moderate lumbar spinal stenosis. Patients and methods. Four university hospitals agreed upon classiþcation of the disease, inclusion and exclusion criteria, radiographic routines, surgical principles and follow up protocols. Moderate stenosis was deþned as a longstanding (> 6 months) low back disorder with pain radiating to the lower limbs and buttocks, aggravated by walking. Narrowing of the dural sac was sagittally < 10 mm or the cross-sectional area < 75 mm2. 94 patients were randomized in the two groups. Results. Sex-adjusted average score of pain in the lower limbs (VAS scale, 0–10) before treatment was 6.5, and 6.3 in the S and NO groups, respectively. Between group difference favoured S group in the follow-up: at six month 2,4 (95% CI 0,9 to 3,8), and at 12 month 1,4 (95% CI 0,1 to 2,8). Sex-adjusted Oswestry score before treatment was 33,0, and 35,8 in the S and NO groups, respectively. Again, between group difference favoured S group: at six months follow-up 9.8 (95% CI 3,2 to 16,4) and at 12 months 12,3 (95% CI 5,2 to 19,5). Walking ability did not differ between the two groups: before treatment 32% of the patients in S group and 30% in NO group walked less than 400, at six month follow-up 23% in both groups, and at one year 18%, and 20% in the S and NO groups, respectively. Conclusions: The results indicate a favorable early effect on perceived outcomes after operative treatment, whereas measured walking ability remained largely unaffected.