Inguinal hernia

Inguinal hernia refers to herniation of intraabdominal contents into the inguinal region, causing a mass in the scrotum or groin. It may also cause pain which worsens during physical activity.

It is the most common type of hernia and is mostly a disorder of older men. There are two types, indirect and direct. Indirect is more common of the two and mostly affects male infants and older men. Direct hernia also mostly affects older men.

Types

In indirect inguinal hernia, the contents herniate into the inguinal canal through the deep inguinal ring. The hernial sac lies within the spermatic cord. It develops due to incomplete obliteration of processus vaginalis during foetal development.

In direct inguinal hernia, the contents herniate directly through the posterior wall of the inguinal canal. The hernial sac lies outside the spermatic cord. It develops due to herniation through a weakened posterior wall of the inguinal canal, usually due to a disease which increases intraabdominal pressure like COPD and constipation. It may also occur during exercise.

During surgery, the two types of inguinal hernia can be differentiated by observing the hernia’s relation to the inferior epigastric vessels. Indirect hernia lies laterally to the vessel, while direct hernia lies medially.

Treatment

Surgical treatment for inguinal hernia may be with tension (Bassini or Shouldice operation) or tension-free with mesh repair (Lichtenstein or laparoscopy).

In Lichtenstein repair, a synthetic mesh is placed between the transversalis fascia and the external oblique aponeurosis during open surgery to reinforce the posterior wall of the inguinal canal. With laparoscopy, transabdominal preperitoneal repair (TAPP) or total extraperitoneal repair (TEP) are options to place the fascia. With TAPP the mesh is placed preperitoneally. With TEP the mesh is placed is an extraperitoneal position, outside the peritoneum.

Recurrence is more common with tension repair, and so tension-free repair is preferred with mesh is usually preferred. If the risk of infection is high (nearby infection, bowel injury), the hernia is very small, or the patient is very young, mesh repair is not preferred. ‎