Comparison of percutaneous endoscopic lumbar discectomy (PELD) and unilateral biportal endoscopic (UBE) discectomy in the treatment of far lateral lumbar disc herniation (FLLDH): a retrospective study - Liang Li; Jilong An; Lei Guo; Xiuqi Shan; Yapeng Sun; Jiaqi Li; Fei Zhang; Wei Zhang (Journal of Orthopaedic Surgery and Research, 2025)