Comparison of unilateral biportal endoscopic lumbar interbody fusion (UBE-LIF) and conventional open TLIF in degenerative lumbar spine disease: a radiological, clinical, and laboratory study

BACKGROUND: Parallel to the advancement of endoscopic techniques, unilateral biportal endoscopic lumbar interbody fusion (UBE-LIF) has become a popular surgical method in the treatment of degenerative lumbar instability. This study aimed to compare the clinical and radiological outcomes of UBE-LIF and conventional open TLIF techniques. METHODS: Patients with single-level degenerative lumbar spondylolisthesis who underwent either UBE-LIF or conventional open TLIF at our institution between January 2021 and May 2024 were included in this single-center study. Clinical outcomes were assessed using Visual analogue scale (VAS) scores, Japanese Orthopaedic Association (JOA) scores, and Oswestry Disability Index (ODI), both preoperatively and postoperatively. Operative time, length of hospital stay, laboratory markers of muscle injury (hemoglobin, CRP, ESR, WBC, myoglobin), and radiological fusion rates were also evaluated. RESULTS: Among the 100 patients who met the inclusion criteria, UBE-LIF was performed in 74, and conventional open TLIF in 26. JOA, VAS-leg, VAS-low back pain, and ODI scores significantly improved in both groups postoperatively (p < 0.001). Clinical scores did not differ significantly between the groups at any time point (p > 0.05). Postoperative blood transfusion was required in 3 patients (11.5%) in the conventional group, whereas none was needed in the UBE-LIF group (p = 0.003). Length of hospital stay was also significantly shorter in the UBE-LIF group (45.4 vs. 98.6 h, p < 0.001). The difference in 12-month postoperative fusion rates between UBE-LIF (100%) and conventional open TLIF (92.3%) was not significant (p = 0.07). Postoperative progression of Goutallier grade (paraspinal muscle degeneration) was not observed in the UBE-LIF group, whereas it occurred in 21 patients (80.8%) in the conventional open TLIF group (p < 0.001). CONCLUSION: Clinical outcomes improved similarly with both techniques. However, postoperative muscle degeneration, intraoperative blood loss, and length of hospital stay were more favorable in the UBE-LIF group. UBE-LIF appears to be a strong alternative to conventional open TLIF.