1210 Quantitative Analysis of Relationship Between Paraspinal Muscle Parameters and Degree of Degenerative Lumbar Spondylolisthesis

INTRODUCTION: Degenerative spondylolisthesis (DS) is a common cause of lumbar stenosis and potentially dynamic instability that frequently causes radiculopathy. While paraspinal muscle degeneration is thought to contribute to spondylolisthesis severity, this relationship has yet to be fully characterized. METHODS: A retrospective analysis was performed of all neurosurgical patients admitted to the Columbia Neurosurgery Spinal Division for treatment of L4-5 DS between January 2018 and March 2024. Preoperative lumbopelvic parameters and slip percentage (SP) were calculated from standing radiographs; paraspinal muscle volume (PMV) and fatty infiltration (FI) were derived from MRI images using 3D Slicer (Earth, TX). Correlation and multiple linear regression analyses were used to assess the relationship between SP and PMV, FI, and spinopelvic parameters. RESULTS: 221 patients (69M/152F) with average SP of 24.18±0.09% were included. Except for intervertebral angle (IVA) and pelvic tilt (PT), other parameters showed no difference between patients with Meyerding Grade I versus II spondylolisthesis. However, PMV was lower and FI higher in the Grade II than Grade I group (p<0.01). There was a positive correlation between SP and metrics of fat replacement (e.g. multifidus FI [r=0.336, p<0.001]) and a negative correlation between SP and metrics of PMV (e.g. total MV [r=-0.270]). A stepwise multivariate regression method was used to develop a model that included MFI, IVA, and LL; while statistically significant, this model only accounted for 16.6% of variance in SP. CONCLUSIONS: In this single center retrospective study, greater degree of spondylolisthesis was modestly associated with lower PMV and increased FI, suggesting that paraspinal muscle degeneration may be one of several important factors in the development of spondylolisthesis.