Shifting Single-level Anterior and Lateral Lumbar Interbody Fusion to the Ambulatory Setting: Comparative Outcomes from a Large Matched Cohort Analysis.

Abstract

Retrospective cohort study. To compare outcomes and healthcare utilization between single-level anterior lumbar interbody fusion (ALIF) or lateral lumbar interbody fusion (LLIF) performed in inpatient and outpatient settings. As healthcare costs continue to rise, there has been a corresponding increase in the number of spine surgeries performed in ambulatory surgery centers. ALIF/LLIF are among the most commonly performed minimally invasive lumbar spine procedures. Large-scale data reporting on outcomes following outpatient ALIF/LLIF remains limited. A retrospective review of the PearlDiver database was conducted, querying for single-level ALIF/LLIF from 2010 to 2022 stratified by service location. Inpatient and outpatient cohorts were matched 1:1 on age range, gender, and the Elixhauser Comorbidity Index (ECI). Outcomes assessed included intraoperative complications, 90-day medical and surgical complications, 30-day and 90-day emergency department (ED) visits and inpatient readmissions, day-of-surgery and 90-day global reimbursements, and five-year revision-free survival. A total of 8,342 patients who underwent outpatient ALIF/LLIF were matched to 8,342 patients who underwent inpatient procedures. Inpatient ALIF/LLIFs were associated with significantly higher rates of intraoperative and 90-day postoperative complications. Patients in the outpatient group were less likely to present to the ED or require hospital readmission at both 30 and 90 days postoperatively (P<0.001 for all) and demonstrated higher revision-free survival at 5 years (log-rank P=0.007). Outpatient procedures were associated with significantly lower reimbursements on the day of surgery (Median [IQR]: $3,199 [$1,270-$6,402] vs. $3,942 [$1,694-$9,433], P<0.001) and within 90 days postoperatively (Median [IQR]: $5,169 [$2,535-$9,480] vs. $6,779 [$3,407-$15,034], P<0.001)). Outpatient ALIF/LLIF procedures are associated with significantly lower rates of postoperative ED visits, hospital readmissions, and total reimbursements compared to inpatient ALIF/LLIF, without an increased risk of complications. These findings support the safety and cost-efficiency of outpatient ALIF/LLIF in appropriately selected patients.