Quantitative Analysis of Relationship Between Paraspinal Muscle Degeneration and Degree of Degenerative Lumbar Spondylolisthesis

Study Design. Clinical retrospective study. Objective. The authors aim to analyze the relationship between paraspinal muscle degeneration and degree of L4–5 Degenerative lumbar spondylolisthesis (DLS). Summary of Background Data. While paraspinal muscle degeneration is thought to contribute to spondylolisthesis severity, this relationship has yet to be fully characterized. Materials and Methods. A retrospective analysis was performed of all neurosurgical patients admitted to the Columbia Neurosurgery Spine Division for treatment of L4–5 DLS between January 2018 and March 2024. Preoperative lumbopelvic parameters and slip percentage (SP) were calculated from standing radiographs; paraspinal muscle volume (MV), fatty volume (FV), and fatty infiltration (FI) of posterior paraspinal muscle were derived from MR images using 3D Slicer. Correlation and multiple linear regression analyses were used to assess the relationship between SP and paraspinal MV, FV, FI, and spinopelvic parameters. Results. Two hundred twenty-one patients with average SP of 23.74±0.09% were included. The female patients had higher SP, lumbar lordosis (LL), pelvic incidence (PI), and lower IVA than the male patients. However, paraspinal MV was lower and FI was higher in the Meyerding grade II and female groups compared with the grade I and male groups ( P <0.01). There was a positive correlation between SP and metrics of fat replacement ( P <0.01) and a negative correlation between SP and metrics of paraspinal muscles volume ( P <0.01) at the L4–5 level. A stepwise multivariate regression ultimately included MFI, IVA, and LL and accounted for 15.2% of the variance in SP. Conclusion. In this single-center retrospective study, greater degree of spondylolisthesis was modestly associated with lower MV and increased FI of the lumbar paraspinal muscles, suggesting that paraspinal muscle degeneration may be one of several important factors in the development of spondylolisthesis.