Introduction: Low back pain is a cause of sleep disorders, which impairs the quality of life (QOL) of patients. Sleep disorders are associated with lumbar spinal stenosis (LSS); however, postoperative effects of LSS surgery on sleep disorders are unknown. A wristwatch-type wearable activity tracker is a well-established tool for objectively measuring sleep disorders. This study aimed to assess sleep disorders in patients with LSS using wearable activity trackers and examine whether surgery improves sleep quality.
Methods: Thirty-nine patients scheduled for LSS surgery (mean age 71.1 ± 8.7 years; 22 men and 17 women) were studied. Sleep disorders in the participants were objectively evaluated using a wearable Micro-Motion logger system (actigraph; Ambulatory Monitoring, Inc.). Sleep efficiency (SEf), mean active count (MAC), and wake after sleep onset (WASO) were measured before and 6 months after the surgery and were compared with those in healthy participants (mean age 67.1 ± 16.8 years; 24 men and 18 women). Moreover, patient-based outcomes of pain and QOL-related scores were measured at each time point. The group with improved SEf after surgery was designated as “non-poor sleepers,” and the group that did not show improvements was designated as “poor sleepers.” The two groups were compared based on patient factors, patient-based questionnaires, and sleep disorder measurements.
Results: Compared to healthy participants, patients with LSS had a significantly longer WASO and poorer SEf (P < 0.05). As for the relationship between sleep disorders and patient factors, we identified a correlation between Oswestry Disability Index scores and SEf. No improvement was found in SEf, MAC, and WASO before and after surgery. Evaluation of each case revealed 21 cases of non-poor sleepers and 12 cases of poor sleepers. Preoperative low back pain was significantly associated with improvement in postoperative sleep quality.
Discussion: Sleep disorders were objectively evaluated in patients with LSS. Sleep quality was compared between patients and healthy participants and was found to be associated with ODI scores. The greater the preoperative back pain, the greater was the improvement in the sleep disorder noted after surgery, and a difference in preoperative symptoms affected postoperative QOL improvements. Sleep disorders are associated with QOL disorders, suggesting that attention to sleep disorders is important in the treatment of patients with LSS. QOL evaluation using wearable devices is a new approach, and further evaluation studies are expected in the future.