A prospective study on surgical-site infections in thyroid operation

Background. To evaluate the incidence and the microbe spectrum of surgical-site infections (SSIs) in patients undergoing elective thyroid operation and to develop a risk factor based predictive model. Methods. This prospective study included 6,778 consecutive patients who underwent thyroid operation at a single institution between 2007 and 2012. SSI was defined according to the Centers for Disease Control and Prevention. Regression models were fitted to evaluate risk factors for SSI. A predictive nomogram was constructed from relevant variables in the multivariable analysis. Discrimination and calibration of the nomogram were assessed. Results. The cumulative incidence of SSI after 30 days was 0.49%. The median time from operation to SSI was 7 days (interquartile range, 4-10.5 days). SSI was classified as superficial incisional in 30 cases (93.8%), deep incisional in 1 case (3.1%), and organ/space in 1 case (3.1%). Staphylococcus aureus was the most common isolate. In multivariable analysis, duration of operation (P = .004) and American Society of Anesthesiologists' score (P = .031) were identified as independent risk factors for SST. These variables formed the basis of a nomogram, which was validated internally by bootstrapping and reached a predictive accuracy of 70.1%. The calibration curve showed a good agreement between predicted probability and actual observation. Conclusion. The cumulative incidence of SSI in thyroid operation is <0.5%. American Society of Anesthesiologists' score and the duration of operation are independent risk factors for SST. Antibiotic prophylaxis may be considered for selected patients based on the individual risk profile.