Comparison of the short-term efficacy of one-hole split endoscopy and unilateral biportal endoscopy in the treatment of l5/s1 lumbar disc herniation with michigan state university grade 2

One-hole split endoscopy (OSE) and unilateral biportal endoscopy (UBE) are both effective minimally invasive techniques for lumbar disc herniation (LDH). In OSE, independent working and observation channels are placed within a single skin incision and are operated separately, whereas UBE uses two separate portals for visualization and instrumentation. Clear guidance for selecting between the two techniques for LDH classified as Michigan State University (MSU) grade 2 is currently lacking. This study compared the clinical efficacy and imaging outcomes of OSE and UBE in the treatment of L5/S1 LDH at MSU grade 2. This retrospective cohort study enrolled patients with L5/S1 LDH admitted between September 2022 and July 2024. Patients were stratified into OSE ( n = 97) and UBE ( n = 119) groups according to the surgical technique performed, and each group was further stratified by MSU classification (types 2B and 2 C). All patients were followed for a minimum of one year. Perioperative parameters, serum prostaglandin E2 (PGE2) and transthyretin (TTR), visual analog scale (VAS) scores, Oswestry Disability Index (ODI), complication rate, recurrence rate, and modified MacNab criteria were compared to assess clinical efficacy. Radiological outcomes included bone loss volume (BLV), facet preservation rate, disc height index (DHI), lumbar range of motion (ROM), sagittal translation (ST), and paraspinal muscle relative cross-sectional area (RCSA). Operation time and hospital stay were similar between groups. Incision length, intraoperative blood loss, and the number of intraoperative fluoroscopy exposures were significantly lower in the OSE group. During at least one year of follow-up, no significant between-group differences were observed in low-back pain VAS, leg-pain VAS, ODI, the modified MacNab excellent/good rate, complication rate, recurrence rate, DHI, ROM, ST, or facet preservation. Compared with the UBE group, the OSE group showed lower early incision-pain VAS scores, lower postoperative PGE2 levels, higher postoperative TTR levels, lower BLV, and better multifidus RCSA preservation ( P < 0.05). OSE and UBE both achieved satisfactory short-term outcomes for MSU grade 2 L5/S1 LDH. In this cohort, OSE was associated with less early incision pain, a lower perioperative inflammatory response, lower measured bone loss, and better multifidus preservation, whereas facet preservation and short-term segmental stability were comparable between groups. These findings should not be interpreted as evidence that UBE inherently requires extensive bone resection, because bone removal during UBE is influenced by anatomy, surgeon proficiency, portal strategy, and technique selection. Surgical technique should be individualized according to patient anatomy, herniation subtype, and surgeon expertise.