Paravertebral Muscle Degeneration Affects Coronal Balance in Patients with Degenerative Lumbar Scoliosis.

OBJECTIVE

This study aimed to investigate the impact of paraspinal muscle (PSM) degeneration on coronal balance in patients with degenerative lumbar scoliosis (DLS).

METHODS

In this retrospective cross-sectional study, 127 DLS patients who underwent spinal fusion surgery were reviewed. Preoperative x-rays and magnetic resonance images were used to assess PSM degeneration, measured by the cross-sectional area (CSA) and fat infiltration rate (FIR) of the multifidus (MF) and erector spinae (ES) muscles. The ratios of the convex to concave sides, namely RCSA and RFIR, were calculated. Coronal balance was classified into types A, B, and C based on the coronal balance distance. One-way analysis of variance and multiple logistic regression were performed to analyze PSM parameters and risk factors for imbalance.

RESULTS

Significant differences were found among the coronal balance types in the RFIR of MF (P = 0.009), RCSA of ES (P < 0.001), FIR of ES (P = 0.017), and RFIR of ES (P = 0.001). Multiple logistic regression identified the RCSA and RFIR of ES as significant for type B imbalance, while the RFIR of MF and FIR of ES were significant for type C.

CONCLUSIONS

PSM degeneration, particularly in the MF and ES muscles, significantly affects coronal balance in DLS patients. Preoperative evaluation of these factors is essential for optimizing surgical outcomes.