Magnetic Resonance Imaging- Defined Lumbar Paraspinal Muscle Morphometry and Lumbopelvic Parameters in Patients with Lumbar Isthmic Spondylolisthesis

Objective: Lumbar isthmic spondylolisthesis (LIS) is a mechanical process characterized by an abnormality in the pars interarticularis that results in anterior translation of the lumbar vertebra.This study aimed to evaluate the multifidus (MF) and erector spinae (ES) cross-sectional areas (CSAs) and lumbopelvic parameters in patients with LIS using magnetic resonance imaging (MRI) and to examine the association of these findings with the spondylolisthesis grade and slip percentage.Methods: This study included 55 patients and 45 healthy individuals.The total CSA (TCSA), functional CSA (FCSA), relative CSA (rCSA), and ratios of the MF and ES muscles, lumbar lordosis angle (LLA), upper lumbar lordosis (ULLA), lower lumbar lordosis, and sacral slope angle were compared between the patient and control groups and between the spondylolisthesis grades.The correlations between these findings and the slip percentage were assessed.Results: The functional and relative CSAs of the MF and ES muscles, MF FCSA/TCSA, and ES FCSA/TCSA were decreased in the patient group.Fatty degeneration was more pronounced in grade 2 LIS than in grade 1. ULLA was elevated in the patient group, and a weak negative correlation was observed between the slip percentage and the MF FCSA/ES FCSA ratio.Conclusion: Patients with LIS demonstrated greater fatty degeneration in MF and ES, and increased ULLA.MRI-based assessments of ES and MF may serve as indicators of LIS progression and spinal instability.The findings of this study highlight the significance of quantitative muscle and lumbopelvic measurements, which may be beneficial in implementing exercise protocols.