Comparative analysis of the efficacy of UBE-PLIF versus conventional PLIF in the treatment of L4-5 degenerative spondylolisthesis.

Background: L4-5 lumbar degenerative spondylolisthesis is a common spinal disease in the middle-aged and elderly population, often accompanied by spinal stenosis and nerve root compression, which seriously affects the quality of life. Traditional posterior lumbar interbody fusion (PLIF) has been widely used in the treatment of such diseases, but it is more traumatic, has a longer recovery period, and has more complications. In recent years, Unilateral biportal endoscopic posterior lumbar Interbody Fusion (UBE-PLIF) has received attention as a minimally invasive treatment. However, the difference in efficacy between UBE-PLIF and PLIF remains to be further explored. This study aimed to compare the clinical outcomes and postoperative imaging changes between the two in the treatment of L4-5 degenerative spondylolisthesis and to provide a basis for clinical decision-making.

Methods: Fifty-nine patients with L4-5 degenerative lumbar spondylolisthesis admitted between January 2021 and January 2024 were retrospectively analyzed in this study, including 28 in the UBE-PLIF group and 31 in the PLIF group. Baseline data (gender, age, history of hypertension/diabetes, BMI), major operative parameters (operative time, number of intraoperative fluoroscopies, postoperative drainage volume) and clinical assessments (low back pain/leg pain VAS score, ODI, SF-36) were collected, and a modified MacNab score was used for final follow-up. Imaging assessments included disc height, (DH), L4-5 segmental lumbar lordosis (SLL), lumbar lordosis (LL), and sagittal slip distance (SSD) preoperatively, at 3 days postoperatively, and the final follow-up, and were compared with the paravertebral muscle cross-sectional area (CSA), the paravertebral muscle fat infiltration (FI), Adjacent segment Pfirrmann grades, and vertebral fusion rate at the final follow-up.

Results: Surgery was completed in both groups, with comparable baseline characteristics and significant postoperative symptom relief. The UBE-PLIF group had significantly less drainage but slightly longer operative time and more fluoroscopic exposures (p < 0.05). Both groups showed significant improvement in leg pain VAS, ODI, and SF-36 scores; however, low back pain VAS at 1 month was significantly lower in the UBE-PLIF group (p < 0.05). Final follow-up revealed no difference in modified MacNab "Excellent "or "Good "Rate (92.9% vs. 90.3%, p > 0.05). Radiologically, both groups demonstrated improved DH, SLL, LL, and SSD, with greater gains in SLL, LL, and SSD in the PLIF group (p < 0.05). Adjacent segment Pfirrmann grades showed no significant difference (p > 0.05). Although the proportion of Grade I fusion was higher in the UBE-PLIF group (64.3% vs. 54.8%), the difference was not statistically significant (p = 0.682). Notably, the UBE-PLIF group had superior paravertebral muscle CSA preservation and lower fat infiltration (p < 0.05). Complication rates were similar (7.1% vs. 12.9%, p = 0.465), with no major adverse outcomes after appropriate management.

Conclusion: Both UBE-PLIF and conventional PLIF can achieve good clinical outcomes in the treatment of L4-5 degenerative lumbar spondylolisthesis. Compared with PLIF, UBE-PLIF has the minimally invasive advantages of less postoperative drainage, faster relief of low back pain, better protection of paravertebral muscles, and lower fat infiltration, and is also comparable to PLIF in terms of complication rate and fusion rate at the final follow-up, and adjacent segmental degeneration. Although PLIF was slightly superior in terms of the magnitude of improvement in some imaging metrics such as SLL, LL, and SSD, the clinical significance of the difference requires further investigation. Overall, UBE-PLIF provides a safe, effective, and less invasive surgical option for L4-5 degenerative spondylolisthesis.