STUDY DESIGN: Retrospective Cohort Study. OBJECTIVES: 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. Primary approaches include anterior lumbar interbody fusion (ALIF) and posterior or transforaminal lumbar interbody fusion (PLIF/TLIF), for which indications are preference driven. This study's objectives were to compare the clinical, radiographic, and functional outcomes of approaches for lumbar spondylolisthesis. METHODS: We conducted a retrospective chart review of 1156 (267 ALIF
889 PLIF/TLIF) patients who underwent ALIF or PLIF/TLIF due to spondylolisthesis at the L4-5, L5-S1, or L4-S1 levels at a large tertiary referral center from 2010 through 2018. Univariate and multivariable linear and logistic regressions were used to compare outcomes including radiologic fusion, change in lumbar lordosis, postoperative complications, and 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 lengths of stay and less blood loss. However, there was no difference in the odds of reoperation within 1 year or any complications. There was also no significant group difference in change in Cobb angle or in any of the QoL variables. CONCLUSIONS: 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. Further research should evaluate the long-term cost-effectiveness of the 2 procedures.