Clinical Features of Sarcopenia in Patients With Lumbar Spinal Stenosis

Study Design. Cross-sectional design. Objective. To investigate the prevalence of sarcopenia and identify factors associated with sarcopenia in patients with lumbar spinal stenosis (LSS). Summary of Background Data. Patients with LSS have a higher prevalence of sarcopenia compared with healthy older adults. However, the clinical features of sarcopenia in patients with LSS are poorly understood and the factors affecting sarcopenia in patients with LSS remain unclear. Methods. Patients diagnosed with LSS based on clinical examination and magnetic resonance imaging findings, and referred to physical therapy, were enrolled. Muscle mass was measured using bioelectrical impedance using InBody S10. We collected a numerical rating scale (NRS) for back pain, the 36-Item Short-Form Survey (SF-36), the Japanese Orthopaedic Association Back Pain Evaluation Questionnaire (JOABPEQ), bone mineral density (BMD), and radiographic measurements of spinal alignment. Sarcopenia was defined according to the Asian Working Group for Sarcopenia guidelines and patients were classified into sarcopenia or nonsarcopenia groups. Results A total of 178 patients were enrolled: 35 in the sarcopenia group and 143 in the nonsarcopenia group. The prevalence of sarcopenia was 19.7%. The average percent of slip (% slip) among patients in the sarcopenia group was significantly higher compared with those in the nonsarcopenia group (P < 0.05). Body mass index ( BMI), BMD, physical function as assessed by the SF-36, and gait disturbance as assessed by the JOABPEQ were significantly lower in the sarcopenia group compared with those in the nonsarcopenia group (P < 0.05). A trend was observed toward between-group differences in back pain on the NRS (P < 0.1). In the logistic regression analysis, significant associations were seen between sarcopenia and % slip (odds ratio 1.15, 95% CI 1.01- 1.30). Conclusion. Patients with LSS and sarcopenia have a higher degree of slippage and lower BMI, BMD, and physical function, and reported more severe low back pain, compared with those without sarcopenia.