Risk Factors for Prolonged Length of Stay in Anterior Lumbar Interbody Fusion

Introduction: Anterior lumbar interbody fusion (ALIF) continues to be a popular approach to surgically treat degenerative spine pathologies. However, only a limited number of studies have evaluated length of stay (LOS) in ALIF. Prolonged hospitalizations have been associated with an increased risk of adverse patient outcomes. This study aimed to identify risk factors for prolonged LOS in patients undergoing single and multi-level ALIF.

Methods: Institutional data involving patients undergoing ALIF by neurosurgery spine faculty working with a specialized vascular surgeon from 1998 – 2020 were retrospectively reviewed. Demographics and intraoperative data were collected. Patients were split into standard and prolonged LOS groups. Prolonged LOS was considered greater than four days (cohort median LOS). Outcome comparisons were conducted using the chi-square exact and Mann-Whitney U test for categorical and continuous data, respectively. Backward stepwise multivariate logistic regression was used to determine independent risk factors for prolonged LOS in ALIF. A univariate analysis was first conducted to identify candidate associations. Variables with p < 0.05 were then included in the multivariate analysis.

Results: 322 ALIF procedures were identified, with 51.6% males (n=166) and 48.4% females (n=156). The mean age was 57.0 years, with 56.4% (n=181) having had prior lumbar surgery. 51.9% (n=167) of the cohort had a prolonged LOS. Patients with prolonged LOS were older (61.8 vs 51.9) and had a history of lumbar spine surgery, diabetes, and hypertension (all p < 0.05). Additionally, prolonged LOS patients had greater blood loss, more levels fused, posterior instrumentation, intraoperative complications, and postoperative complications (all p < 0.05). Multivariate analysis revealed a history of hypertension, single and multi-level posterior instrumentation, amount of blood loss, and postoperative complications to be significant predictors of prolonged LOS (all p < 0.05).

Conclusion : History of hypertension, posterior instrumentation, amount of blood loss, and postoperative complications were found to be independent risk factors for prolonged LOS in ALIF.