Incidence of Contralateral Metachronous Inguinal Hernia on Long Term Follow-Up after Unilateral Inguinal Hernia Repair: a Systematic Review and Meta-Analysis

The repair of inguinal hernias is a common surgical procedure. Some patients will need a second operation after developing a metachronous contralateral inguinal hernia (MCIH). The suggestion has been made to strengthen the contralateral side at the same time as primary unilateral surgery. In this systematic review we aim to determine how many adult patients with a unilateral inguinal hernia will develop a MCIH. This review was reported in line with PRISMA guidelines. We performed a literature review in PubMed Publisher, Embase, Google Scholar and Cochrane Library until May 2021, including articles reporting MCIH after unilateral inguinal hernia repair in adults. As outcome measure, the number of patients diagnosed with a MCIH was registered. A total of 19 articles with a total of 277,288 patients were included. The combined estimate for MCIH after meta-analysis equaled 8.3