Negative appendicectomy and perforation rates in patients undergoing laparoscopic surgery for suspected appendicitis

Background: Despite widespread use of imaging technologies including ultrasonography and computed tomography, rates of negative appendicectomy and perforated appendicitis remain high. This trend analysis examined whether rates of negative appendicectomy and perforated appendicitis have decreased over time, and sought to evaluate clinical predictors associated with negative appendicectomy and perforated appendicitis. Methods: This analysis was based on the prospective database of the Swiss Association of Laparoscopic and Thoracoscopic Surgery (SALTS). All patients aged 12 years and over undergoing emergency laparoscopic appendicectomy between 1995 and 2006 were included. Unadjusted and risk-adjusted logistic regression analyses were performed. Results: A total of 7964 patients underwent laparoscopic appendicectomy, of whom 7452 (93.6 per cent) had acute appendicitis and 512 (6.4 per cent) had a macroscopically normal appendix. Perforation occurred in 1230 (16.5 per cent) of those with appendicitis. In multivariable analysis, younger age (12-18 years), female sex, absence of local or generalized peritonitis and an early point during the study period were significant predictors of negative appendicectomy. For perforated appendicitis, significant predictors included age over 36 years, presence of localized or generalized peritonitis, and high American Society of Anesthesiologists grade. The rate of negative appendicectomy decreased from 12.7 per cent in 1995 to 2.8 per cent in 2006, there being a significant reduction in both unadjusted and risk-adjusted analyses (P < 0.001 for trend). In adjusted analyses, the rate of perforated appendicitis did not increase significantly over time. Conclusion: The rate of negative appendicectomy decreased over time, without an accompanying increase in perforated appendicitis. The risk of having a negative appendicectomy was highest in girls aged 12-18 years without local or generalized peritonitis during the early study period, whereas perforation was associated with age over 36 years, presence of localized or generalized peritonitis, and greater co-morbidity.