Anterior Lumbar Interbody Fusion Offers Safer Inpatient Profiles But at Greater Cost Compared With Posterolateral Fusion: National Outcomes for Spondylolisthesis From 2016 to 2022

INTRODUCTION: Degenerative lumbar spine disease represents a leading global source of disability, with spondylolisthesis contributing substantially to the burden of low back pain and impaired function. Lumbar fusion remains a commonly performed surgical strategy for degenerative spondylolisthesis, although decompression alone versus decompression with fusion continues to be an area of active debate, particularly in select low-grade cases. This study aimed to compare inpatient complications, discharge disposition, mortality, and costs between anterior lumbar interbody fusion (ALIF) and posterolateral fusion (PLF) for degenerative lumbar spondylolisthesis. METHODS: The National Inpatient Sample was queried from 2016 to 2022 for elective admissions of adults with a primary diagnosis of lumbar spondylolisthesis undergoing ALIF or PLF. Encounters with both approaches or additional interbody techniques were excluded. Outcomes included perioperative complications, in-hospital mortality, discharge disposition, length of stay, and inflation-adjusted costs. Survey-weighted logistic regression and generalized linear models adjusted for demographics, comorbidities, and hospital factors. Significance was set at the P < 0.05 level. RESULTS: We identified 57,475 weighted admissions: 12,410 ALIF and 45,065 PLF. In adjusted models, PLF was associated with higher odds of transfusion (OR, 2.60; P < 0.001), acute posthemorrhagic anemia (OR, 1.47; P < 0.001), cerebrospinal fluid leak/dural tear (OR, 3.57; P < 0.001), and the adverse-events composite (OR, 1.68; P < 0.001). PLF also demonstrated greater odds of nonroutine discharge (OR, 1.19; P = 0.002). In-hospital mortality was exceedingly rare and not meaningfully different. ALIF was associated with higher mean costs ($43,000 vs. $31,500; P < 0.001) despite shorter length of stay (2.81 vs. 3.31 days; P < 0.001). CONCLUSIONS: ALIF for degenerative spondylolisthesis was associated with fewer perioperative complications and lower odds of nonroutine discharge than PLF, though at substantially higher inpatient costs. These findings highlight a clinical-economic tradeoff between anterior and PLF strategies at the national level. LEVEL OF EVIDENCE: III.