- To assess whether perioperative surgical outcomes associated with thyroid operations were different in those with benign or malignant conditions, we queried the NSQIP, a multi-institutional, risk-adjusted, prospective U.S. database. A total of 10,838 patients who underwent initial thyroid surgery as their principal operation during 2005-2007 were analyzed. Analysis focused on demographics, preoperative risk factors, operative details, postoperative complications, return to the operating room, and length of surgical stay. Thirty-three percent of patients had a postoperative diagnosis of malignancy. Mean operating time was 121.8 min (119.3 min benign, 123.0 min malignant, P = .004) and average length of stay 1.16 days (1.12 days benign, vs. 1.21 days malignant, P = .007). Overall morbidity (return to the operating room plus medical complications) was 3.8% for the entire cohort, significantly higher in patients with malignant disease (4.9 vs. 3.3%, respectively, P < .001). On multivariate analysis, American Society of Anesthesiologists class, congestive heart failure (odds ratio [OR] 6.83, 95% confidence interval [CI] 1.81-25.80), dyspnea, and return to the operating room (OR 5.41, 95% CI 3.1-9.45) were significant risk factors for complications, while malignant disease (OR 2.25, 95% CI 1.75-2.9), outpatient status (OR 3.16, 95% CI 2.4-4.17), and other complications (OR 6.46, 95% CI 3.61-11.54) were risk factors for returning to the operating room. Patients undergoing thyroid surgery for malignancy have a longer length of stay (1.21 days), longer operation times, and return to the operating room at higher rates compared to those with benign disease. Malignancy itself is only an independent risk factor for return to the operating room and not other complications; surgeons may consider keeping those patients overnight for observation.