Study design: Propensity score-adjusted prospective cohort study.
Objective: To compare the incidence of complications in patients undergoing single-level lumbar discectomy between the inpatient and outpatient settings, to determine baseline 30-day complication rates for lumbar discectomy, and to identify independent risk factors for complications.
Summary of background data: Lumbar discectomy is the most common spinal procedure performed and can be done on an outpatient basis. Lower costs, greater patient satisfaction, and equivalent safety have been reported with outpatient surgery.
Methods: Patients undergoing lumbar discectomy between 2005 and 2010 were selected from The American College of Surgeons (ACS) National Surgical Quality Improvement Program (NSQIP) database. Patient selection was based on a single primary current procedural terminology code. To ensure comparable inpatient and outpatient cohorts, patients with multilevel procedures were excluded. Thirty-day postoperative complications and preoperative patient characteristics were identified and compared. Propensity score matching and multivariate logistic regression analysis were used to adjust for selection bias and identify predictors of 30-day morbidity.
Results: Of the 4310 lumbar discectomy cases, 2658 (61.7%) underwent an inpatient hospital stay after surgery, whereas 1652 (38.3%) patients had outpatient surgery. Unadjusted overall complication rates (6.5% vs. 3.5%, P < 0. 0001) were higher in those undergoing inpatient surgery. After propensity score matching, overall complication rate was still higher with the inpatient cohort (5.4% vs. 3.5%, P = 0.0068). Adjusted comparison using multivariate logistic regression also demonstrated a significantly higher rate of complication for inpatients (odds ratio, 1.521; 95% confidence interval, 1.048-2.206). Age, diabetes, presence of preoperative wound infection, blood transfusion, operative time, and an inpatient hospital stay were all independent risk factors of short-term complication after lumbar discectomy.
Conclusion: After adjusting for confounders using propensity score matching and multivariate logistic regression analysis, patients undergoing outpatient lumbar discectomy had lower overall complication rates than those treated as inpatients. Surgeons should consider outpatient surgery for lumbar discectomy in appropriate candidates.