Surgical Site Infections and Postoperative Intraabdominal Abscesses in Appendicitis: An ACS-NSQIP Study

Author(s):
Joshua Tseng; Tara Cohen; Rodrigo Alban

Background:

Surgical site infections (SSI) and postoperative intraabdominal abscesses (IA) are common postoperative complications for appendicitis. Although laparoscopic appendectomies have been associated with reductions in postoperative pain, in-hospital length of stay, and SSI rates, other studies associate laparoscopic appendectomies with higher rates of postoperative IA.

Hypothesis:

The aim of the study is to evaluate risk factors for surgical site infections and postoperative intraabdominal abscesses after appendectomy using a large national database.

Methods:

The 2016 American College of Surgeons – National Surgical Quality Improvement Program Procedure-Targeted Appendectomy database was used to identify cases with appendectomies for appendicitis confirmed on pathology. Cases were divided into the following cohorts: those with incisional SSI, postoperative IA, any SSI, and no postoperative infections. Comparisons between cohorts were made using the student’s t-test and Pearson’s chi-squared test where appropriate. Binary logistic regression analysis was used to identify independent predictors of incisional SSI and postoperative IA.

Results:

A total of 11,314 patients underwent appendectomies for appendicitis, with an overall SSI rate of 4.5%.  Patients with any SSI were more likely to be older (44.6 vs 39.5 years old, p<.001), male (59.3% vs 52.1%, p=.002), BMI>35 (20.8% vs 13.9%, p<.001), diabetic (9.3% vs 4.8%, p<.001), have preoperative sepsis (56.3% vs 43.7%, p<.001), open surgery (8.9% vs 3.0%, p<.001), laparoscopic conversion to open (9.3% vs 2.1%, p<.001), and longer operative times (68.0 vs 52.5 minutes, p<.001).  They were less likely to have uncomplicated appendicitis (34.2% vs 77.6%, p<.001), or have the surgical specimen placed in a bag prior to removal (85.4% vs 91.0%, p<.001).  On regression analysis, appendicitis complicated by abscess or perforation was an independent risk factor for both incisional SSI and IA.  Open surgery, conversion to open surgery, and BMI>35 had higher odds of incisional SSI.  Preoperative sepsis, diabetes, and longer operative times had higher odds of IA, while placing the specimen in bag had lower odds of IA.

Conclusions:

Incisional SSI and postoperative IA are common complications after appendectomy.  Independent predictors of postoperative infections include complicated appendicitis, open surgery, conversion to open surgery, BMI>35, diabetes, preoperative sepsis, and longer operative times.  Placing the surgical specimen in a bag prior to removal has lower odds of intraabdominal abscesses.