243. Predictors of inpatient admission in the setting of anterior lumbar interbody fusion

Abstract

BACKGROUND CONTEXT While the anterior lumbar interbody fusion (ALIF) procedure may be amenable to ambulatory surgery, it has been hypothesized that limitations such as the risk of postoperative ileus and vascular complications has hindered transition to the outpatient setting. Identification of independent risk factors predisposing patients to inpatient stays of greater than 24 hours after ALIF may facilitate better postsurgical outcomes, target modifiable risk factors, and assist developing screening tools to transition appropriate patients to the ambulatory surgery center (ASC) setting. PURPOSE The purpose of this study is to identify the most relevant risk factors that predispose patients to ≥ 24-hour admission following ALIF. STUDY DESIGN/SETTING Retrospective PATIENT SAMPLE A total of 135 patients who underwent single or multilevel ALIF. OUTCOME MEASURES Postoperative complications, postoperative fever, blood transfusion, cardiovascular complications, longer inpatient stay METHODS A prospectively maintained surgical registry was reviewed for patients undergoing single or multi-level ALIF between May 2006 and September 2019. Demographics, preoperative diagnosis, perioperative variables, and postoperative complications were evaluated according to their elevation of relative risk (RR) of an inpatient stay ≥ 24 hours. A Poisson regression model evaluated predictors of inpatient stays ≥ 24 hours. A stepwise backward regression model identified risk factors for inpatient admission of greater than or equal to 24 hours. RESULTS A total of 135 patients underwent single or multilevel ALIF. 53% of the cohort was female and 54.8% was ≤50 years of age. Nine (6.7%) patients were discharged in less than 24 hours and 126 remained admitted for ≥24 hours. The average inpatient stay was two days. The most common postoperative complication was a temperature ≥100.4°F (n=5, 3.8%). Other complications included blood transfusions (n=4, 3.0%) and cardiovascular complications (n=3, 2.2%). Bivariate analysis revealed that having a multilevel procedure on L4L5 and either L3L4 or L5S1 (RR=1.07 or 1.09, p=0.003) had the largest RR elevation for an inpatient stay of ≥ 24 hours. Stepwise multivariate analysis of risk factors revealed foraminal stenosis (RR=0.84, P=0.045), degenerative disc disease (RR=1.25, P=0.028), estimated blood loss >50 mL (RR=1.25, P=0.011), and BMI ≥30 kg/m2 (RR=1.16, p=0.030) to be significant predictors for inpatient stays of ≥24 hours. CONCLUSIONS Our study provides an incidence of demographics, perioperative characteristics, and postoperative complications as they pertain to patients undergoing ALIF. This preliminary investigation identified the most relevant risk factors to be considered before appropriately transitioning ALIF procedures to the ASC. Further studies of preoperative characteristics are needed to elucidate ideal ASC ALIF patients. FDA DEVICE/DRUG STATUS This abstract does not discuss or include any applicable devices or drugs.