150. Outpatient vs inpatient anterior lumbar surgery: a multisite, comparative analysis of patient safety measures

BACKGROUND CONTEXT The frequency and complexity of spinal surgery performed in an outpatient setting has been steadily increasing in the past decade. However, data on the safety and efficacy of most spinal procedures adapted to the outpatient setting is lacking. The few studies that have reviewed specific outpatient procedures have mostly focused on anterior cervical surgery, and have drawn conflicting conclusions. To our knowledge, there is no published literature on the feasibility, safety and effectiveness of anterior lumbar surgery (fusions and disc replacements) in an outpatient setting. PURPOSE The purpose of this study is to evaluate the safety and efficacy of outpatient anterior lumbar procedures compared to procedures done at an inpatient setting in a matched cohort of patients. STUDY DESIGN/SETTING This study is a retrospective matched cohort study of patients who underwent an anterior lumbar interbody fusion (ALIF) or a lumbar artificial disc replacement (LADR) at an inpatient facility, compared to a free-standing ambulatory surgery center. PATIENT SAMPLE Consecutive adult patients of several orthopedic and neurosurgical spine surgeons, who underwent elective stand-alone ALIF or LADR or a hybrid of fusion and disc replacement, at either an inpatient tertiary care facility or an outpatient surgical center were studied. A minimum of 90-day follow-up was required. OUTCOME MEASURES Reoperation rates, readmission rates, 90-day complication rates, and length-of-stay data were collected and compared between the two groups. Complications that were specifically assessed included neurological injury, durotomy, vascular injuries, bowel injuries, postoperative ileus, epidural or retroperitoneal hematomas, postoperative urinary retention, urinary tract infections, deep vein thrombosis (DVT), pulmonary embolism (PE), cardio-pulmonary complications, intractable pain, surgical site infection, and death. METHODS Medical records of 231 consecutive patients who underwent ALIF or LADR procedures between 2016-2019 were reviewed. The inpatient and outpatient cohorts were matched with regards to age, sex, body mass index (BMI), and medical comorbidities. Length of stay, complication data, reoperations, and readmissions were recorded and compared between the groups. RESULTS A total of 124 (54%) inpatient and 107 (46%) outpatient patients were reviewed for this study. The two groups had similar baseline characteristics. While there was a trend toward fewer complications, reoperations and readmission for the outpatient cohort, the differences were not statistically significant. The overall 90-day complication rate was 5.6% for the inpatient cohort, and 0.9% for the outpatient cohort. Of the patients in the inpatient cohort, 3.2% were re-admitted within 90 days, compared to 1.9% of those in the outpatient cohort. Reoperation rate was 1.6% for the inpatient cohort. No patient from the outpatient cohort required reoperation. The average hospital stay was 56.9 hours, compared to 5.2 hours at the ambulatory surgery center. CONCLUSIONS There were no statistically significant differences between the 90-day complication and reoperation rates between anterior lumbar procedures performed in an inpatient vs outpatient setting in a matched cohort of patients. Furthermore, the overall 90-day readmission rates were lower for outpatients than for inpatients. Our results support the conclusion that anterior lumbar procedures including 1- and 2-level ALIF and LADR procedures can be performed safely in an outpatient setting. FDA DEVICE/DRUG STATUS This abstract does not discuss or include any applicable devices or drugs.