The impact of preoperative multifidus muscle morphology on surgical outcomes in lumbar degenerative spondylolisthesis: a retrospective cohort study.

INTRODUCTION: the multifidus muscle is a key stabilizer of the lumbar spine. While its deterioration has been associated with degenerative spinal conditions, the specific impact of its preoperative morphology on surgical outcomes remains unclear. The objective of this study is to evaluate the relationship between preoperative multifidus muscle morphology (cross-sectional area and fatty degeneration) and clinical-surgical outcomes following lumbar fusion surgery. MATERIAL AND METHODS: a retrospective cohort study of 99 patients aged 40-65 years with L4-L5 degenerative spondylolisthesis undergoing lumbar fixation and arthrodesis (2022-2024). Preoperative MRIs assessed cross-sectional area multifidus (CSAM) and fatty degeneration. Three spine surgeons performed measurements with substantial interobserver reliability (. RESULTS: = 0.80). Clinical outcomes (ODI, Roland Morris, SF-36, VAS), surgical variables, and complications were analyzed. the cohort (31.31% male, 68.69% female; mean age 59.15 ± 8.78 years) showed significant positive correlations between CSAM and intraoperative blood loss (r = 0.249, p = 0.013) and postoperative complications (r = 0.217, p = 0.031). Fatty degeneration demonstrated no significant association with complications (p = 0.214) or clinical improvement. All patient groups showed significant clinical improvement at 12 months postoperatively regardless of fatty infiltration severity. CONCLUSIONS: larger multifidus muscle volume correlates with increased surgical complexity, while fatty degeneration does not predict complications or clinical outcomes. These findings highlight the importance of comprehensive muscle morphology assessment in preoperative planning. A retrospective cohort study was conducted.