Balancing the Risk of Postoperative Surgical Infections: A Multivariate Analysis of Factors Associated With Laparoscopic Appendectomy From the NSQIP Database

To establish the relationship between operative approach (laparoscopic or open) and subsequent surgical infection (both incisional and organ space infection) postappendectomy, independent of potential confounding factors. Although laparoscopic appendectomy has been associated with lower rates of incisional infections than an open approach, the relationship between laparoscopy and organ space infection (OSI) is not as clearly established. Cases of appendectomy were retrieved from the American College of Surgeons National Surgical Quality Improvement Program (NSQIP) database for 2005 to 2008. Patient factors, operative variables, and the primary outcomes of incisional infections and OSIs were recorded. Factors associated with surgical infections were identified using logistic regression models. These models were then used to calculate probabilities of OSI in clinical vignettes demonstrating varying levels of infectious risk. A total of 39,950 appendectomy cases were included of which 30,575 (77%) were performed laparoscopically. On multivariate analysis, laparoscopy was associated with a lower risk of incisional infection [odds ratio (OR) 0.37, 95% confidence interval (CI) 0.32-0.43] but with an increased risk of OSI after adjustment for confounding factors (OR 1.44, 95% CI 1.21-1.73). For a low-risk patient, probability of OSI was calculated to be 0.3% and 0.4%, respectively, for open versus laparoscopic appendectomy, whereas for a high-risk patient, probabilities were estimated at 8.9% and 12.3%, respectively. Laparoscopy was associated with a decreased risk of incisional infection but with an increased risk of OSI. The degree of this increased risk varies depending on the clinical profile of a surgical patient. Recognition of these differences in risk may aid clinicians in the choice of operative approach for appendectomy.