This study retrospectively compared clinical and radiological outcomes of unilateral biportal endoscopic lumbar interbody fusion (ULIF) to those of conventional posterior lumbar interbody fusion (PLIF). Seventy-one ULIF (age, 68 ± 8 years) and 70 PLIF (66 ± 9 years) patients for one lumbosacral segment followed more than 1 year were selected. Parameters for surgical techniques (operation time, whether transfused), clinical results [visual analogue scale (VAS) for back and leg pain, Oswestry disability index (ODI)], surgical complications (dural tear, nerve root injury, infection), and radiological results (cage subsidence, screw loosening, fusion) between the two groups were compared. The PLIF group demonstrated a significantly shorter operation time and more transfusions done than the ULIF group. The VAS for leg pain in both groups and for back pain in the ULIF group significantly improved at 1 week, while the VAS for back pain in the PLIF group significantly improved at 1 year. ODI scores improved at 1 year in both groups. Complication rates were not significantly different between groups. Fusion rates with definite and probable grades were not significantly different between groups. However, the ULIF group had significantly (P = 0.013) fewer cases of definite fusion and more cases of probable fusion [43 (74.1%) and 15 (25.9%) cases, respectively] than the PLIF group [58 (92.1%) and 5 (7.9%) cases, respectively]. ULIF is less invasive while just as effective as conventional PLIF in improving clinical outcomes and obtaining fusion. However, ULIF has a longer operation time than PLIF and requires further development to improve the fusion grade.
Keywords: Clinical outcome; Posterior lumbar interbody fusion; Radiological outcome; Unilateral biportal endoscopic lumbar interbody fusion.