Degeneration of lumbar paravertebral muscles in lumbar degenerative kyphosis with dynamic sagittal imbalance
Abstract Background: The aim of this study was to probe the degeneration of lumbar paravertebral muscles in lumbar degenerative kyphosis (LDK) with dynamic sagittal imbalance (DSI).Method: A total of 132 patients with LDK were enrolled in the study. According to the ΔSVA of the full-spine lateral radiographs before and after walking, enrolled patients were divided into two groups: DSI group (31 cases) and control group (42 case). Lumbar magnetic resonance imaging examination was taken for each subject. Fat infiltration area (FIA)and muscle muscularity of multifidus (MF) and erector spinae (ES) were quantitatively measured though Image J software. Independent-sample t test were performed for comparison of quantitative variables between two groups. P value<0.05 was considered statistically significant.Result: DSI group had lower muscle muscularity both in ES and MF than control group. ES muscularity at L2 level was 0.42±0.08 in DSI group and 0.82±0.17 in control group. (p=0.016). ES muscularity at L4 level was 0.36±0.11in DSI group and 0.76± 0.22 in control group. (p<0.001).MF muscularity at L2 level was 0.17±0.08 in DSI group and 0.36±0.07in control group. (p<0.001). MF muscularity at L4 level was 0.34±0.18 in DSI group and 0.48±0.14 in control group. (p<0.001).DSI group had higher FIA both in ES and MF than control group.ES FIA at L2 level was 0.50±0.17 in DSI group and 0.31±0.10 in control group. (p=0.023). ES FIA at L4 level was 0.55±0.27 in DSI group and 0.34±0.07 in control group. (p<0.001).MF FIA at L2 level was 0.63±0.22 in DSI group and 0.36±0.12 in control group. (p<0.001). MF FIA at L4 level was 0.76±0.31 in DSI group and 0.40±0.19 in control group. (p<0.001). Conclusions: LDK patients with DSI suffered lower muscle muscularity and higher FIA both in ES and MF compared to control group. Our study revealed that the weakness of the paravertebral muscles plays an important role in DSI process, targeted paravertebral muscle strengthening training may be a potentially effective treatment for this disease.