Surgical Outcomes of Interval Laparoscopic Appendectomy for Appendiceal Abscess and Predictors of Conversion to Open Surgery

The present study was performed to clarify the benefits of interval laparoscopic appendectomy (ILA) for appendiceal abscess by comparison with emergency laparoscopic appendectomy (ELA), and to identify any risk factors associated with conversion to open ILA. Among 903 adult patients with acute appendicitis, we conducted a retrospective analysis of 58 patients with appendiceal abscess who had undergone either ILA after conservative treatment (ILA group; n = 44) or ELA (ELA group; n = 14). The two groups were compared with regard to surgical outcomes, and the risk factors for conversion to open surgery were also estimated in the ILA group. ILA was superior to ELA in terms of blood loss (median 5 ml vs. 50 ml; p < 0.01), rate of conversion to open surgery (16% vs. 43%; p < 0.05), postoperative hospital stay (median 4 days vs. 8 days; p < 0.01), and morbidity (7% vs. 36%; p < 0.01). In the ILA group, analysis of clinical factors showed that a higher C-reactive protein level, escalation of antibiotic treatment, and longer hospitalization during conservative treatment were significantly associated with conversion. Interval laparoscopic appendectomy following conservative treatment is less invasive and has lower morbidity. However, the presence of severe inflammation at the time of conservative treatment substantially affects conversion from laparoscopic to open surgery.