Nocturnal Cramps in Patients with Lumbar Spinal Canal Stenosis Treated Conservatively: A Prospective Study

STUDY DESIGN: Prospective cohort study with questionnaire. PURPOSE: To compare the treatment outcome of nocturnal leg cramps in lumbar spinal canal stenosis (LSCS) patients on conservative treatment with historical surgical cohorts and to determine the sensitivity and specificity as well as positive predictive value and negative predictive value of knee flexion test suggested for LSCS patient. OVERVIEW OF LITERATURE: True prevalence of nocturnal leg cramps in LSCS patients as well as the clinical outcome of its surgical treatment have been reported. METHODS: A questionnaire suggested from previous study with minor modifications was used in this study. Clinical data was collected. Knee flexion test was performed in two groups. RESULTS: The prevalence of nocturnal leg cramp was higher in the LSCS group compared to the control group (second group). In LSCS patients, 38 (88%) had improved leg cramps after the conservative treatment, 3 (6.97%) remained unchanged, and 2 (4.6%) had worsened leg cramps. Of the 43 patients, 21 (48.8%) had no disturbance to their activities of daily living. In the LSCS group, the sensitivity and specificity of the knee flexion test was 53.5% and 33.3%, respectively. The knee flexion test in the LSCS group had a positive predictive value and a negative predictive value of 65.71% and 23.1%, respectively. CONCLUSIONS: Our study demonstrated that nocturnal leg cramps were significantly more frequent in LSCS patients than in the control group.