The effect of sarcopenia in the clinical outcomes following stand-alone lateral lumbar interbody fusion

BACKGROUND: Sarcopenia has been found to affect the postoperative outcomes of lumbar surgery. The effect of sarcopenia on the clinical outcomes in patients who underwent stand-alone lateral lumbar interbody fusion (LLIF) has not yet been examined. OBJECTIVE: To investigate whether sarcopenia affects the Oswestry Disability Index (ODI) and visual analog scale (VAS) score for back pain following single-level stand-alone LLIF. METHODS: Patients who underwent a single level stand-alone LLIF for lumbar diseases were retrospectively investigated. Sarcopenia was defined according to the diagnostic algorithm recommended by the Asian Working Group for Sarcopenia. Patients were divided into the sarcopenia (SP) and non-sarcopenia (NSP) group. Univariate analysis was used to compare with regards to demographics and clinical outcomes. Multivariate logistic regression was performed to elucidate factors predicting poor clinically improvement. RESULTS: Sixty-nine patients were enrolled, with 16 and 53 patients in the SP and NSP group respectively. In the SP group, patients were much older (P = 0.002), their body mass index was significantly lower (P < 0.001), the percent of women was higher (P = 0.042), and the skeletal muscle mass index (SMI) (P < 0.001) and gait speed were much lower (P = 0.005). The postoperative ODI scores were much higher and the improvement rate was much lower (both P < 0.001) in the SP group, whereas VAS scores for back pain showed no difference between the two groups. SMI and gait speed had a moderate and weak correlation with the final ODI score, respectively. Low SMI and low gait speed were independently associated with poor clinical outcomes at the final follow-up. CONCLUSIONS: Sarcopenia impacts the final clinical outcomes of stand-alone LLIF for lumbar diseases. Low SMI and low gait speed were negative impact factors for the clinical improvement after stand-alone LLIF.