Chronological Changes in Appendiceal Pathology Among Patients Who Underwent Appendectomy for Suspected Acute Appendicitis.

BACKGROUND: Given recent advances in imaging and the development of diagnostic parameters, the rate of unnecessary appendectomy (i.e., negative appendectomy) has been decreasing. However, the incidence of acute appendicitis (AA) in elderly patients is rising due to the aging of society. We aimed to identify chronological changes in demographics and appendiceal pathology among patients who underwent appendectomy for suspected AA. METHODS: Data from 881 patients who underwent appendectomy for suspected AA between January 2006 and December 2017 were analyzed. The final diagnosis was based on intraoperative findings, pathological reports, and clinical course. Negative appendectomy was defined as the absence of appendiceal diseases including inflammation, fibrosis, and neoplasm. We compared demographics and appendiceal pathology between early (2006-2011) and late study phases (2012-2017). RESULTS: The mean age of patients with pathologically proven AA (n = 761) was significantly greater in the late phase than in the early phase (38.6 +/- 19.8 years vs. 44.0 +/- 20.3 years, p = 0.0002), and the ratio of patients with AA aged >== 75 years was also increased (from 5.6 to 8.6%, p = 0.1120). The incidences of complicated appendicitis (defined as perforated or gangrenous appendicitis) and appendiceal diverticulitis (AD) were increased in the late phase compared to those in the early phase (61.3% vs. 77.2% and 3.7% vs. 6.6%, respectively). The negative appendectomy rate was significantly reduced in the late phase compared to that in the early phase (10.0% vs. 2.5%, p < 0.0001). CONCLUSIONS: During a 12-year period, the mean age of patients with AA and the incidences of complicated appendicitis and AD increased, whereas the negative appendectomy rate decreased.