Comparative Analysis of Uniportal and Biportal Endoscopic Transforaminal Lumbar Interbody Fusion in Early Learning Stage: Technical Considerations and Radiological Outcomes

Abstract

Objective: This study compared the clinical and radiological outcomes of uniportal endoscopic and biportal endoscopic transforaminal lumbar interbody fusion (TLIF) for lumbar degenerative disease during the early learning stage of the technique. Methods: We retrospectively analyzed patients who underwent uniportal endoscopic TLIF (n=15) and biportal endoscopic TLIF (n=19) between January and October 2021 during the first year of adoption of these techniques. Radiological parameters, including Bridewell fusion and subsidence grading, were evaluated by x-ray and computed tomography (CT) at 3-month, 6-month, and 1-year follow-up visits. Clinical outcomes were evaluated using the visual analogue scale (VAS) and the Oswestry Disability Index (ODI). Results: Uniportal endoscopic TLIF showed significantly higher frequencies of intraoperative endplate injuries (uniportal [20%] vs. biportal [0%], p=0.01) and 1-year cage subsidence (uni-portal [60%] vs. biportal [26.3%], p=0.04) than biportal endoscopic TLIF. The 1-year fusion rates did not differ significantly between the 2 surgical groups (uniportal [93.3%] vs. biportal [89.5%], p=0.37). Neural complications such as postoperative dysesthesia and dural tears oc-curred in uniportal endoscopic TLIF. There were no significant differences in the VAS for back and leg pain or ODI. Conclusion: Complete endplate preparation under endoscopic guidance improved interbody fusion, and this procedure may be feasible in the early learning stage, regardless of the type of endoscope. Both endoscopic TLIF techniques achieved good clinical outcomes and fusion rates. However, unskilled use of the cage guide device caused endplate breakage and neural injury during uniportal endoscopic cage insertion. Uniportal endoscopic TLIF may require more experience for appropriate cage insertion.