Correlation of paraspinal muscle mass with decompensation of sagittal adult spinal deformity after setting of fatigue post 10-minute walk

Abstract

Objective: The purpose of this study was to investigate the changes in spinopelvic parameters before and after the setting of muscle fatigue along with its correlation with pre-existing paraspinal and psoas muscle mass. Methods: Single-center retrospective review of prospectively collected data was conducted on 145-adults with symptomatic loss of lumbar lordosis (LL). Radiographs were taken before and after walking for 10 minutes. Magnetic resonance imaging was used to calculate paraspinal muscle (PSM) cross-sectional area (CSA), mean signal intensity, fatty infiltra-tion (FI), and lean muscle mass at thoracolumbar junction (T12) and lower lumbar level (L4). Psoas CSA was calculated at L3. Patients were divided into 2 groups namely compen-sated sagittal deformity (CSD) (SVA ≤ 4 cm, PT > 20°) and decompensated sagittal deformity (DSD) (SVA > 4 cm, PT > 20°) based on prewalk measurements. Results: Initial mean SVA was 1.8 cm and 11 cm for CSD and DSD respectively (p < 0.01). After walking, significant deteriorations in SVA, PT–LL (p < 0.01) were observed in CSD without significant change in thoracic kyphosis (TK). All sagittal parameters in DSD deteri-orated significantly. DSD group had significantly poorer PSM quality at T12 and L4 com-pared to CSD group. In CSD group, sagittal decompensation correlated with muscle quali-ty, i.e., decreases in LL (ΔLL) correlated with CSA of PSM/vertebral body (VB) at L4 (r =-0.412, p = 0.046) while increases in TK (ΔTK) correlated with CSA of PSM/VB at T12 (r = 0.477, p = 0.018). ΔSVA and ΔPT correlated with FI at L4 (r = 0.577, p = 0.003 and r =-0.407, p = 0.048, respectively). DSD group, had weak correlations (-0.3 < r