Sarcopenia and fatty degeneration of paraspinal muscle associated with increased sagittal vertical axis in the elderly: a cross-sectional study in 71 female patients

Purpose Both increased sagittal vertical axis (SVA) and sarcopenia affect performance of daily activities and morbidity in the elderly; however, little is known regarding their relationship. The aim of this study was to analyze the association between sarcopenia and increased SVA. Methods This retrospective study included 71 female patients aged between 60 and 85 years. Entire-spine radiography was used to measure radiological parameters. A bioelectrical impedance analyzer was used to measure the skeletal muscle mass index (SMI). Gait velocity (GV) and hand grip strength (HGS) were examined as well. Lumbar spine magnetic resonance imaging was employed to measure the functional cross-sectional area (FCSA) and fat signal fraction (FSF) of the paraspinal muscle as well. The subjects were divided into two groups according to the SVA (group I; SVA > 50 mm and group II; SVA ≤ 50 mm). Results The group I showed lower GV, HGS, and SMI than the group II ( p < 0.001, < 0.001, and = 0.001, respectively). The prevalence of sarcopenia was higher in the group I (56.7%) than in the group II (17.1%) ( p = 0.001). The group I also showed lower FCSA and higher FSF than the group II ( p < 0.001). In multivariate analysis, the FSF (odds ratio 1.308, p = 0.004) and HGS (odds ratio 0.792, p = 0.023) were correlated with increased SVA. In addition, the BMI (odds ratio 0.756, p = 0.037), SVA (odds ratio 1.051, p = 0.031), and FCSA (odds ratio 0.995, p = 0.012) were correlated with sarcopenia. Conclusion Sarcopenia and fatty degeneration of paraspinal muscle are closely related to increased SVA in the elderly.