T. Adediji1,2, L. Rivera1,2, A. Karmaker1,2, M. Wallack1,2, J. Mariadason1,2 1Metropolitan Hospital Center,Surgery,New York, NY, USA 2New York Medical College,Surgery,Valhalla, NY, USA
Introduction: Appendectomy is the commonest emergency surgical operation worldwide, with the majority being performed laparoscopically in the USA now. Laparoscopic appendectomies have comparatively fewer complications including superficial surgical site infection(SSI), although some studies suggest that laparoscopic appendectomies may have a higher risk of organ space SSI. A small percentage of cases require conversion from laparoscopic to open appendectomy, but little is known about the impact of conversion on SSI rates. We postulated that conversion caused a higher SSI rate than both laparoscopic and open appendectomy based on our experience. The purpose of this study was to compare superficial and deep SSI rates for converted, laparoscopic and open appendectomies and if our hypothesis was confirmed, to elucidate possible ways of predicting the need for conversion preoperatively.
Methods: The medical records of all patients undergoing appendectomies at Metropolitan Hospital from January 2004 to December 2011 were reviewed. Cases were divided into laparoscopic, open and converted categories, and the infection rate for each operative method was calculated. Alvarado score and CT findings for cases that required conversion were examined.
Results:In total, 718 cases were reviewed. There were 370 (51.4%) laparoscopic appendectomies, 337 (46.9%) open appendectomies, and 11 (1.5%) converted appendectomies. Laparoscopic appendectomies had a 1.08% rate of superficial SSI (4/370), and a 1.08% rate of deep SSI (4/369). Open appendectomies had a 0.89% rate of superficial SSI (3/337), and a 0.59% rate of deep SSI (2/337). Converted appendectomies had an 18.1% rate of superficial SSI (3/12), and a 9.09% rate of deep SSI (1/11). This difference was statistically significant (p<0.05).
Conclusion: Laparoscopic appendectomies were associated with comparable rates of superficial SSI but higher rates of deep SSI when compared with open appendectomies. The overall rates of superficial SSI (1.25%) and deep SSI (0.97%) in our series were low. Our low superficial SSI rate for open appendectomy may be due to the practice of most surgeons of packing contaminated wounds open with delayed primary closure. Converted appendectomies had the highest infection rates overall when compared with laparoscopic and open appendectomies (p<0.05). This has not been highlighted in the literature previously, and is possibly attributable to the need for multiple incisions, a higher proportion of incisions with primary closures, more advanced disease, and longer duration of surgery. This was not clear from analysis of the 11 cases of converted appendectomy in this series. If a method is created, for predicting which cases would need conversion to open appendectomy, it could help reduce SSI rates.