Association Between Lumbar Muscle Function and Reoperation in Patients With Recurrent Lumbar Disc Herniation After Percutaneous Endoscopic Lumbar Discectomy.

STUDY DESIGN: Retrospective matched case-control study. OBJECTIVE: To investigate whether lumbar muscle function is associated with reoperation after percutaneous endoscopic lumbar discectomy (PELD) due to recurrent lumbar disc herniation (rLDH). SUMMARY OF BACKGROUND DATA: In addition to established risk factors, paraspinal muscle quality, which is measured by cross-sectional area (CSA) and fatty infiltration (FI), is related to lumbar degeneration but remains unknown as a predictor for rLDH recurrence after PELD. METHODS: Patients who underwent PELD successfully from January 2016 to February 2022 in a single institution were enrolled in this study. On T2 axial preoperative magnetic resonance images (MRI) at the L1-L2, L2-L3, L3-L4, L4-L5, and L5-S1 disc levels, a transformer-based segmentation algorithm was used to contour the psoas major (PS), multifidus (MF), and erector spinae (ES) muscles. The CSA of each muscle was subsequently calculated, and the Otsu method was applied to discriminate between muscle and fat tissue, thereby enabling quantitative assessment of FI. Statistical methods were used to compare whether there were statistical differences between the case and control groups. Spearman correlation analysis was performed. RESULTS: A total of 2603 patients were enrolled in this study. Fifty-seven patients underwent reoperation for rLDH, and 57 patients were selected from the remaining 2546 nonrecurrent patients as matched controls. Statistical analysis revealed significant differences between the case and control groups in: the CSA of PS at L3-L4 (P=0.041), L4-L5 (P=0.036), and L5-S1 (P=0.044); the CSA of ES at L1-L2 (P=0.049) and L2-L3 (P=0.026); and the FI of all muscles at all disc levels, except PS at L1-L2 (P=0.602) and ES at L1-L2 (P=0.227). CONCLUSION: This study showed that lumbar muscle function is associated with reoperation in rLDH patients after PELD. Smaller CSA and higher FI of core lumbar muscles were associated with an increased likelihood of rLDH after PELD.