Contralateral processus closure to prevent metachronous inguinal hernia: A systematic review

Inguinal hernia repair is one of the most frequent operations in pediatric surgery and is increasingly performed laparoscopically. The latter introduced new momentum in the debate on the necessity of contralateral exploration, as the rates of contralateral patent processus vaginales and metachronous inguinal hernias determine whether a routine closure would be overtreatment or useful prevention.We searched MEDLINE via PubMed, Web of Science and Scopus at the 6th of September 2017; reference lists and CrossRef were snowballed for reports citing identified studies. Eligibility criteria were age <18 years, preoperative diagnosis of unilateral hernia, laparoscopic evaluation, and publication since January 2012. Studies using hernioscopy (transinguinal laparoscopy) were excluded. We reported our systematic review following PRISMA criteria.We included 32 reports consisting of 19,188 pediatric patients diagnosed with unilateral inguinal hernia. Of these, 38.5% (95% confidence interval: 34%-43.1%) had a contralateral open processus vaginalis concomitantly found during laparoscopic inguinal hernia repair. A secondary analysis using nine studies that compared open and laparoscopic approaches found that prophylactic closure of contralateral patent processus vaginales resulted in a risk difference of 5.7% (95% confidence interval: 3.6%-7.7%; P < 0.001) following 2691 (42.8%) procedures (nine studies: Ten of 6282 patients operated laparoscopically had a metachronous hernia, versus 286 of 5764 with open hernia repair).Prophylactic closure of a contralateral patent processus vaginalis reduces the number of metachronous inguinal hernias, but about 18 procedures must be performed to prevent one metachronous inguinal hernia, indicating that the indication should be based on personal circumstances of the patient.