Abstract Purpose This study aims to investigate the influence of multifidus muscle fat infiltration on clinical outcomes in lumbar disc herniation (LDH) undergoing percutaneous endoscopic lumbar discectomy (PELD). Methods A retrospective analysis was conducted on 224 patients who underwent lateral PELD, with complete one-year follow-up data. Patients were divided into two groups based on preoperative MRI evaluation of L4 multifidus muscle fat infiltration: a mild group (