Unilateral Biportal Endoscopic Lumbar Interbody Fusion: A Technical Note and an Outcome Comparison with the Conventional Minimally Invasive Fusion.

Background: In the past few decades, the minimally invasive technique for spine surgery has developed extensively from the scope of decompression until fusion surgeries to reduce damages to the normal anatomical structure. Unilateral biportal endoscopic lumbar interbody fusion (ULIF) is one of the fusion options which is readily available without a sophisticated minimal invasive instrument. Our aim is to introduce ULIF experience in our center and comparing the result with conventional minimally invasive lumbar interbody fusion (MIS-TLIF).

Methods: This is a retrospective cohort study of 145 lumbar spondylolisthesis cases that underwent fusion surgery with either ULIF or the conventional MIS-TLIF. All of the patients were observed within a 12-month follow-up period to evaluate the back pain and leg pain Visual Analogue Score (VAS), the Oswestry Disability Index (ODI), the 36-Item Short Form Health Survey (SF-36), and fusion rate.

Results: The leg pain VAS was similarly improved in both groups. ULIF has a significant back pain improvement on direct post operation and at the 3-months follow-up (p value 0.032 and 0.046 respectively). ULIF group also had a significantly better improvement of ODI scores on the early post-operative period (p=0.045). However, both groups similarly showed improvement of ODI score and the SF-36 at the 3-, 6-, and 12- months follow up.

Conclusion: Full endoscopic fusion surgery with ULIF offers a comparable long-term outcome and a significantly better back pain VAS reduction in short-term follow up compared to the conventional MIS-TLIF. ULIF, with further improvement, can be the next gold standard in managing degenerative lumbar spine conditions.