Implications of the presence of the vermiform appendix inside an inguinal hernia (Amyand's hernia): a systematic review of the literature

Purpose To identify and sum all available evidence pertaining to the management of Amyand's hernia (AH). Methods A systematic search of the MedLine, Scopus, and Google Scholar databases was performed for studies published until January 2020. Results In total, 111 studies incorporating 161 patients were identified, 96 (86.4%) being case reports, 11 (9.9%) case series, and 4 (3.7%) retrospective patient cohorts. Mean patient age was 58.5 +/- 19.6 years with 136 (83.9%) being males and 25 (16.1%) females. Furthermore, 149 (92.5%) cases were right-sided hernias while 12 (7.5%) cases were left-sided. Overall, 62.3% of patients presented emergently and 77.3% of patients' cohort were eventually diagnosed with incarcerated AH. Preoperative diagnosis of AH was established in 23.1% of patients and was achieved either by ultrasound (25%) or CT scan (75%). Operative findings consisted of normal appendix in 73 (45.4%) cases, uncomplicated appendicitis in 62 (38.5%) patients, and perforated appendix in 26 (16.1%). Regarding patients with appendicitis, mesh placement was reported for 17 (21.2%), herniorrhaphy was performed for 51 (63.7%) while 12 (15.1%) patients did not undergo hernia repair during the initial operation. Mesh utilization rates were significantly higher in patients with a normal appendix. Seven cases involved AH containing appendiceal neoplasms. Thirteen cases (8.6%) of postoperative complications were documented and a single case of postoperative death. Conclusion AH is a rare type of inguinal hernia usually complicated by appendicitis. Hernia reconstruction should be tailored to each patient individually according to the extent of inguinal canal inflammation.