Anterior versus Transforaminal Lumbar Interbody Fusion for Degenerative Spondylolisthesis: A Propensity-Weighted Cohort Comparison of Clinical, Radiographic, and Functional Outcomes

Introduction: Lumbar spinal fusion is an increasingly utilized surgery within the United States attributed to an aging population with an increasing prevalence of degenerative spinal disease. Its primary approaches include anterior lumbar interbody fusion (ALIF) and posterior or transforaminal lumbar interbody fusion (PLIF/TLIF), for which indications are preference driven. ALIF is the more expensive procedure necessitating vascular surgery; however, it may produce better patient outcomes and necessitate fewer revision procedures. As the literature is mixed and generally fails to control for patient presentation and operative characteristics, we aimed to compare the clinical, radiographic, and functional outcomes of each approach for degenerative lumbar spondylolisthesis.

Methods: We conducted a retrospective chart review of 1,231 (285 ALIF; 946 PLIF/TLIF) patients who underwent ALIF or PLIF/TLIF due to degenerative spondylolisthesis at the L4-5, L5-S1, or L4-S1 levels at a large tertiary referral center from 2010 through 2018. Propensity score weighting was utilized to balance preoperative and intraoperative variables between the ALIF and PLIF/TLIF cohorts. Additionally, univariate analyses, multivariate linear regressions, and logistic regressions were used to compare outcomes. The primary outcomes evaluated were radiologic fusion, change in lumbar lordosis, and postoperative complications. Secondary outcomes evaluated were the pre- to postoperative changes in quality-of-life (QoL) variables.

Results: Between propensity-weighted cohorts, multivariate regression showed markedly increased odds of radiographic fusion for the ALIF cohort (Odds Ratio [OR]: 2.50, 95% Confidence Interval [CI]: 1.51-4.15]. ALIF patients had shorter length of stay and less blood loss. However, there was no difference in odds for reoperation within one year or any complications. There was also no significant group difference in change in Cobb angle or in any of the QoL variables.

Conclusion : These results indicate that ALIF may have greater radiologic success of fusion. However, when controlling for confounders, there is no difference in clinical outcomes between the approaches. These results indicate that surgeons should continue to perform the procedure with which they prefer. For the healthcare system, further research should evaluate the long-term cost-effectiveness of the two procedures.