The effectiveness and appropriateness of Interval Laparoscopic Appendectomy on adult appendiceal mass, a retrospective cohort

Background: Appendiceal mass sometimes requires extended resection and difficult to treat postoperative complications. Interval appendectomy has been performed mainly in the field of pediatric surgery to avoid them. Recently, there are a few reports on interval laparoscopic appendectomy (ILA). We examined not only the safety and effectiveness of ILA for adult appendiceal mass (AAM), but also the appropriateness of ILA for which cases should be treated non-surgically for ILA or converted to surgical treatment. Methods: Among 956 appendectomies performed between April 2012 and March 2018, there were 49 cases of AAM, of which 34 cases underwent ILA; ILA group. The safety and efficacy of ILA were examined by comparing with 477 cases of adult uncomplicated appendicitis underwent laparoscopic appendectomy (LA); LA group. The appropriateness of ILA was examined by comparing with the remaining 15 cases of AAM; non-ILA group. Results: The ILA group had a longer operation time than the LA group, but the postoperative hospital stay was shorter, and no significant difference were found in the bleeding volume, the days required for oral intake of solid food, and the perioperative complications. Examining the factors for failure of non-surgical treatment or relapse of inflammation during interval period, higher WBC day3 / day0 was found to be an independent risk factor. Conclusion: ILA against AAM was almost as safe and effective as LA for adult uncomplicated appendicitis. WBC day3 / day0 may be effective as an objective parameter for judging the termination of non-surgical treatment for ILA. This determination to convert ineffective non-surgical treatment to surgical treatment earlier may reduce the burden on the patient.