Objective: To explore the applicability of bone reamer and trephine for foraminoscopy in percutaneous endoscopic lumbar discectomy(PELD), and to provide a theoretical basis for foraminoplasty options in clinical practice. Methods:This study was a prospective cohort study. Sixty-three consecutive patients who underwentPELD for lumbar disc herniation between May 2021 and July 2022 were analysed. Foraminoplasty were performed by bone reamer or trephine. The amount of bone resected and the area enlarged during foraminoplasty by both tools were measured by 3D slicer as well as Digimizer software, and the numbers of fluoroscopic views were recorded. Results: The bone reamer resected less bone in the Superior Articular Process (SAP) than the trephine (t=17.507, PConclusion:Bone reamer was safer and trephine was more efficient for foraminoscopy in PELD. An area of preoperative foraminoplasty zone of 54.55 mm²can be used as a critical value: bone reamer reduced the risk for cases above the value, while trephine improved the efficiency for cases less than the value.