Patients with acute appendicitis can present at different stages of the disease process, ranging from mild mucosal inflammation to frank perforation with abscess formation. The reported overall incidence of acute appendicitis varies with age, gender, and geographical differences. Interestingly, while the incidence of non-perforated appendicitis in the United States decreased between 1970 and 2004, no significant decline in the rate of perforated appendicitis was observed despite the increasng use of computed tomography (CT) and fewer negative appendectomies.
Of 32,683 appendectomies sampled from the American College of Surgeons National Surgical Quality Improvement Program (ACS-NSQIP) hospitals between 2005 and 2008, 5,405 patients (16.5%) had a preoperative diagnosis of acute appendicitis with peritonitis/abscess.
The definition of complicated appendicitis varies slightly in the literature. Clinicopathological diagnoses (gangrenous, perforated, appendiceal abscess/phlegmon) of acute appendicitis are commonly used for its definition. Classically, patients at the extremes of age are more likely to present with complicated appendicitis. Similarly, pre-morbid conditions including diabetes and type of medical insurance are significantly associated with the risk of perforation.
The importance of early appendectomy has also been emphasized to prevent perforation of the appendix and the sub- sequent negative impact on patient outcomes. However, more recent meta-analysis data supports the safety of a relatively short (12–24 h) delay before appendectomy, which was not significantly associated with increased rate of complicated appendicitis. Teixeira et al. also showed that the time to appendectomy was not a significant risk factor for perforated appendicitis but did result in a significantly increased risk of surgical site infection.
The outcome of patients with complicated appendicitis is significantly worse than patients with uncomplicated appendicitis. A population-based study from Sweden showed that, in a risk-adjusted model, patients with perforated appendicitis were 2.34 times more likely to die after appendectomy than non- perforated appendicitis patients. Because of its higher mortality and morbidity in patients with complicated appendicitis, the management of complicated appendicitis has evolved significantly over the last few decades.
Open or Laparoscopic Surgery
Since the first laparoscopic appendectomy was described by Semm in 1983, multiple studies have compared operative time, complication rates, length of hospital stay, hospital cost, and other outcomes between open and laparoscopic appendectomy for acute appendicitis. The most recent Cochrane review included 67 studies showing that laparoscopic appendectomy was associated with a lower incidence of wound infection, reduced postoperative pain, shorter postoperative length of hospital stay, and faster recovery to daily activity. In contrast, reduced risk of intra-abdominal abscesses and shorter operative time were found as the advantages of open appendectomy.
Due to increased surgeon experience in uncomplicated appendicitis, laparoscopic appendectomy is more frequently attempted even in complicated appendicitis cases as an alternative approach to open appendectomy. Although the general surgical steps for complicated appendicitis are similar to those for uncomplicated appendicitis, the laparoscopic procedure can be more technically demanding. Therefore, conversion from laparoscopic appendectomy to open appendectomy can be expected.
Despite these concerns, the laparoscopic approach in patients with com- plicated appendicitis has been proven to be safe and comparable to open appendectomy. Retrospective studies using a large database in the United States uniformly showed more favorable clinical outcomes (mortality, morbidity, length of hospital stay, readmission rate) and hospital costs in patients who underwent laparoscopic appendectomy when compared to open appendectomy. The real risk of developing an intra- abdominal abscess after laparoscopic appendectomy remains unclear. A meta-analysis by Markides et al. found no significant difference in the intra-abdominal abscess rate between laparoscopic and open appendectomy for complicated appendicitis, whereas Ingraham et al. showed a higher likelihood of developing an organ-space surgical site infection in patients undergoing laparoscopic appendectomy.