Foraminoplasty at the Base of the Superior Articular Process with Bone Drilling for Far-Downward Discs in Percutaneous Endoscopic Lumbar Discectomy: A Retrospective Study

PURPOSE: Percutaneous endoscopic lumbar discectomy (PELD) is usually used to treat lumbar disc herniation (LDH). This study aims to describe PELD by foraminoplasty in the treatment of far-downward migrated LDH and to demonstrate the clinical efficacy by a retrospective evaluation. PATIENTS AND METHODS: Between January 2017 and July 2018, 41 patients with far-downward migrated LDH were treated with PELD by foraminoplasty at the base of the superior articular process (SAP). Clinical efficacy was evaluated with a visual analogue scale (VAS) score, the Oswestry disability index (ODI), and the modified Macnab criteria. Postoperative follow-up data (1 month, 6 months, 18 months) were recorded. RESULTS: The surgical levels included L2/3 (1 patient), L3/4 (1 patient), L4/5 (17 patients), and L5/S1 (22 patients). The VAS and ODI scores indicated a significant improvement 18 months after surgery (mean ± standard deviation, VAS, 6.9±1.3 versus 0.5±0.8; ODI, 66.3±12.2 versus 14.0±8.2, respectively). Based on the modified Macnab criteria, 92.7% of patients had a good-to-excellent rate. There were three patients with a dural tear, and one patient had recurrent disc herniation. CONCLUSION: PELD by foraminoplasty at the base of the superior articular process is a good method for treating far-downward migrated LDH.