The incidence and natural course of occult inguinal hernias during TAPP repair

One of the proposed advantages of laparoscopic inguinal hernia repair is complimentary inspection of the contralateral side and possible detection of occult hernias. Incidence of occult contralateral hernias is as high as 50 %. The natural course of such occult defects is unknown and therefore operative rationale is lacking. This study was designed to analyze the incidence of occult contralateral inguinal hernias and its natural course. A total of 1,681 patients were diagnosed preoperatively with unilateral inguinal hernia. None of these patients had complaints of the contralateral side preoperatively. All patients underwent laparoscopic inguinal hernia transabdominal preperitoneal (TAPP) repair. Operative details were analyzed retrospectively. Patients with occult contralateral defects were identified and tracked. Patients with an evident occult hernia received immediate repair. Patients with a smaller beginning or incipient hernia were followed. In 218 (13 %) patients, an occult hernia was found at the contralateral side during preoperative exploration. In 129 (8 %) patients, an occult true hernia was found. In 89 (5 %) patients, an occult incipient hernia was found. An incipient hernia was defined as a beginning hernia. All patients with an incipient hernia were followed. The mean follow-up was 112 (range 16-218) months. Twenty-eight (32 %) patients were lost to follow-up. In the 61 remaining patients, 13 (21 %) occult incipient hernias became symptomatic requiring repair. The mean time between primary repair and development of a symptomatic hernia on the contralateral side was 88 (range 24-210) months. This study shows that the incidence of occult contralateral hernias is 13 % during TAPP repair of unilateral diagnosed inguinal hernias. In 5 % of the cases, the occult hernia consisted of a beginning hernia. Eventually, one of five will become symptomatic and require repair. These outcomes support immediate repair of occult defects, no matter its size.