Comparison of Midterm Outcomes between Biportal Endoscopic Transforaminal Lumbar Interbody Fusion and Oblique Lumbar Interbody Fusion with Lateral Vertebral Body Screw Fixation for Single Level Spondylolisthesis

Abstract Objective: The purpose of this study is aiming to compare the intra-operative, radiographic, and mid-term clinical outcomes between direct decompression of BE-TLIF and indirect decompression of OLIF in patients with single level spondylolisthesis Method: Between December 2020 and May 2022, patients with single level spondylolisthesis and received either OLIF or BE-TLIF from the authors’ orthopedic departments were selected to enroll in this retrospective study. Results: A total of 34 patients that underwent single-level OLIF and 30 patients that received single-level BE-TLIF in the spine department of our institutions were included. Both groups had similar demographic parameters. BE-TLIF showed significantly less blood loss compared to that of OLIF (p<0.001). The OLIF group yielded shorter operation time than the BE-TLIF group (p=0.002). The improvement in restoration of follow-up segmental lordosis was significantly more in OLIF group than BE-TLIF group (p<0.001). The OLIF group was significantly better in post-operative VAS back pain (p=0.035). The cage subsidence rates between the two groups were not significantly different. The follow-up Oswestry Disability Index (ODI) and overall visual analogue scale were comparable between the 2 groups without significant difference. Conclusion: While OLIF still offers superior results in restoration of lumbar lordotic angle and short term post-operative back pain, the use of endoscopic technique in BE-TLIF may achieve comparable radiographic and clinical outcomes in cage subsidence rate and follow-up VAS back/leg pain compared to the indirect decompression of OLIF.