General Session: Value and Outcomes in Spine Surgery

Presented by: A. Samuel - View Audio/Video Presentation (Members Only)


M. Fu(1), A. Samuel(2), E. Sheha(1), P. Derman(1), S. Iyer(1), J. Grauer(2), H.J. Kim(1)

(1) Hospital for Special Surgery, New York, NY, United States
(2) Yale University School of Medicine, Orthopaedics, New Haven, CT, United States


Background: Anterior cervical discectomy and fusion (ACDF) is increasingly performed on an outpatient basis as a means of realizing healthcare cost savings. Previous studies examining the safety of outpatient ACDF have largely established one-level ACDF to be a safe procedure. The morbidity and safety of outpatient two-level ACDF as separate from one-level ACDF are poorly characterized.

Purpose: To determine the safety and morbidity of two-level ACDF as an outpatient procedure relative to inpatient cases, in comparison to one-level ACDF.

Methods: Prospectively-collected data from ACDF cases were queried from the American College of Surgeons National Surgical Quality Improvement Program from 2011-2013. Patient demographics and comorbidities, as well as thirty-day postoperative adverse events were collected. Modified Charlson Comorbidity Indices (CCI) were used as a marker of overall comorbidity burden. A propensity score model was used to adjust for outpatient versus inpatient status, based on hospital billing. Univariate and multivariate analyses were performed to compare complication rates between outpatient and inpatient cases, for one- and two-level ACDF. Risk factors for complications were identified with multivariate regression.

Results: Of 14,434 ACDF cases, 2,993 (20.7%) were coded as outpatient while 11,441 (79.3%) were inpatient. There were 9,636 (66.8%) one-level cases and 4,250 (29.4%) two-level cases. Patients that underwent outpatient surgery tended to be younger with lower modified CCI scores. Propensity score adjustment successfully reduced this selection bias to statistically insignificant levels. For one-level ACDF, the overall rate of having any postoperative adverse event was 3.76% for inpatient cases and 1.13% for outpatient cases. With propensity-adjusted multivariate logistic regression, outpatient cases had decreased rates of any adverse event (odds ratio [OR] 0.37, 95% confidence interval [CI] 0.24-0.57), any major adverse event, pulmonary complications, return to the operating room, blood transfusions, urinary tract infections, and any minor adverse events. For two-level ACDF, the rates of having any postoperative adverse event was 4.02% for inpatient cases and 1.38% for outpatient cases. With propensity-adjusted multivariate analysis, outpatient cases had decreased rates of any adverse event (OR 0.44, 95% CI 0.24-0.81), any major adverse event, any pulmonary complication, and return to the operating room. Risk factors for developing any postoperative complication following one- or two-level ACDF in this analysis included age > 65, modified CCI of 4 or greater, male gender, end-stage renal disease, hypertension, disseminated cancer, pulmonary comorbidity, cardiac comorbidity, and chronic steroid use.

Conclusions: Two-level ACDF performed on an outpatient basis had low complication rates, with no additional morbidity risk compared to inpatient cases. Surgeons should consider the identified risk factors in preoperative risk stratification, with outpatient surgeries performed on appropriate patients. Figure 1. Odds ratios (OR) with 95% confidence intervals (CI) for postoperative events, as outpatient cases versus inpatient cases. 95% confidence intervals excluding OR of 1.0 indicates statistical significance (P < 0.05).

Figure 1