Y-Style Unilateral Biportal Endoscopic Far-Lateral Approach for L5S1 Foraminal Stenosis

OBJECTIVE: High iliac crest can pose an anatomical challenge for classic paraspinal unilateral biportal endoscopic far-lateral approach (C-UBEFLA). To overcome this, we devised a modified technique, the Y-style unilateral biportal endoscopic far-lateral approach (Y-Style-UBEFLA), which introduces a lateral working portal. The name derives from the morphological resemblance of the portal arrangement to the letter "Y". To compare the effectiveness of the Y-Style-UBEFLA with the C-UBEFLA in treating L5S1 foraminal stenosis (L5S1FS). METHODS: A retrospective review was conducted on 47 patients diagnosed with L5S1FS, with 24 undergoing C-UBEFLA and 23 undergoing Y-Style-UBEFLA. Surgical outcomes were assessed preoperatively and postoperatively, including pain scores (visual analog scale), disability index (Oswestry Disability Index), postoperative lateral facet preservation rates, and MacNab grading at 1-year follow-up. RESULTS: Both approaches demonstrated comparable operative times, blood loss, and pain relief outcomes at one year. The Y-Style-UBEFLA group exhibited significantly greater preservation of the superior articular process (100% vs. 70.8%, P < 0.001). Additionally, 1-year MacNab outcomes favored the Y-style-UBEFLA group (P = 0.026). CONCLUSIONS: The Y-style-UBEFLA technique offers improved surgical access to the L5S1FSwhile enhancing preservation of spinal structures. It effectively addresses the anatomical challenges posed by high iliac crests, providing superior clinical outcomes and better facet preservation. The Y-Style-UBEFLA represents a viable alternative to C-UBEFLA for managing L5S1FS, especially in high iliac crest patients.