The correlation among subcutaneous lumbar spine index, paraspinal muscle parameters, and lumbar bone mineral density in patients with lumbar spondylolisthesis

Objectives: To analyze the correlation among subcutaneous lumbar spine index (SLSI), paraspinal muscle parameters, and lumbar bone mineral density (BMD), and to evaluate their predictive value on lumbar BMD for patients with lumbar spondylolisthesis. Materials and methods: A total of 216 patients with lumbar spondylolisthesis were included. All of them were divided into groups of normal bone mass, osteopenia, and osteoporosis (OP) according to BMD of L1–4 measured by dual-energy X-ray absorptiometry (DXA). SLSI was obtained by computed tomography, and paraspinal muscle parameters were calculated by the Image J software. The differences between SLSI and paraspinal muscle parameters were compared in 3 groups. Correlation analysis and multiple linear regression were used to analyze the relationship between parameters and lumbar BMD. Results: SLSI and paraspinal muscle parameters were analyzed among 3 groups. There was a significant difference in cross-sectional areas (CSAs) of psoas major (PS) and quadratus lumborum (QL), PS index, relative cross-sectional areas (rCSAs) of PS and QL, fatty infiltration (FI) of multifidus (MF) and erector spinae (ES) between normal bone mass group and osteopenia group, normal bone mass group and OP group ( p < 0.05). Correlation analysis among body mass index (BMI), SLSI, paraspinal muscle parameters, and BMD was adopted for all included patients. There were positive correlations among BMI, CSAs of PS and QL, PS index, rCSAs of PS and QL, and lumbar BMD ( p < 0.05). There were negative correlations among MF index, FI of PS, MF and ES, and lumbar BMD ( p < 0.05). The regression equation of lumbar BMD: BMD = −3.461 + 0.063 × BMI + 0.943 × rCSA of PS − 3.871 × FI of ES ( R 2 = 0.111). Conclusions: For patients with lumbar spondylolisthesis, smaller CSAs of flexor muscle group and more FI of paraspinal muscles are related to less bone mass and lower lumbar BMD. Combined with BMI, rCSA of PS and FI of ES have predictive value on lumbar BMD. For patients with both lumbar spondylolisthesis and OP, those who have higher SLSI are estimated to have less bone mass.