Comparative outcomes of ULIF versus OLIF-LP for lumbar spondylolisthesis: an early efficacy study

This study aims to conduct a comparative analysis of clinical outcomes and postoperative complications between unilateral biportal endoscopic lumbar interbody fusion (ULIF) and oblique lateral interbody fusion (OLIF) in the surgical management of degenerative lumbar spondylolisthesis (DLS).

We retrospectively analyzed DLS patients treated with ULIF or OLIF. The basic information of patients, surgical information (operation time, blood loss, hospitalization period), and complications were recorded. Clinical outcomes was comprehensively evaluated using the visual analog scale (VAS) for pain, the Oswestry Disability Index (ODI), and imaging parameters such as disc height (DH), foraminal height (FH), and crosssectional area of the spinal canal (CSA). The intervertebral fusion rate was evaluated according to the Bridwell assessment system 1 year after surgery.

This study included 46 patients, with 25 undergoing unilateral biportal endoscopic lumbar interbody fusion (ULIF) combined with percutaneous pedicle screw fixation and 21 receiving oblique lateral interbody fusion (OLIF) with lateral plate fixation. Baseline characteristics were comparable between the two groups. The OLIF group exhibited statistically significant reductions in both operative duration and intraoperative blood loss when compared to the ULIF group (79.05 ± 5.16 min vs. 123.40 ± 8.72 min; 39.81 ± 4.09 mL vs. 91.40 ± 7.02 mL, P < 0.05). Postoperative assessments revealed that OLIF patients exhibited superior early outcomes, with lower VAS scores for low back pain and improved ODI scores at 7 days post-surgery. However, these differences were no longer evident by the 3-month follow-up. Both surgical approaches significantly enhanced DH, FH and CSA compared to preoperative values, with no notable intergroup differences observed during follow-up. The fusion rates were similar between the two techniques (OLIF: 90.48% vs. ULIF: 92.31%, P > 0.05). Complications in the OLIF group included 2 cases of cage subsidence and 2 instances of lumbosacral plexus injury. In the ULIF group, adverse events comprised 2 cases of cage subsidence, 1 screw malposition, 1 endplate injury, and 1 nerve injury. No statistically significant difference in complication rates was found between the groups (P > 0.05).

Both ULIF and OLIF are effective methods for the treatment of DLS. Compared with OLIF, ULIF has a longer operation time, more blood loss, and a higher risk of dural injury, but their clinical effects are comparable.