Morphology-based investigation of metachronous inguinal hernia after negative laparoscopic evaluation – is it acquired indirect inguinal hernia?

PurposePatients who developed apparent metachronous contralateral inguinal hernia (MCIH) after negative laparoscopic diagnosis have been reported. We performed this study to investigate the morphological characteristics and etiology of this phenomenon.Patients and MethodsA consecutive series of 1,747 patients (858 boys and 889 girls) with symptomatic unilateral inguinal hernia were studied. During laparoscopic percutaneous completely extraperitoneal closure, morphological appearances at the asymptomatic groin were inspected for contralateral patent processus vaginalis (CPPV) with definitive criteria. If positive CPPV was identified, it was closed by the same technique used for the affected side. The patients were reviewed for occurrence of metachronous contralateral hernia.ResultsA total of 755 patients (43.2%) had positive CPPV. Of the 992 patients whose CPPVs were evaluated as true negative, eight (seven boys, one girl) developed MCIH (time taken, three months to five years six months). During second-look operations, morphological appearances of the CPPV that was originally considered as true negative CPPV was found to be wide open.ConclusionsDespite a true negative evaluation by laparoscopy, there was a 0.8% chance of developing a MCIH. This phenomenon was male-oriented and may be acquired indirect inguinal hernia without preceding of CPPV.