Rare Abdominal Hernias

The uncommon types of abdominal hernias include :

• Spigelian hernia
• Obturator hernia
• Lumbar hernia
• Sciatic hernia
• Interparietal hernia
• Perineal hernia
• Richter’s hernia
• Internal hernia

Spigelian Hernia

What is a spigelian hernia?

It is a rare hernia that occurs through the spigelian fascia which lies just outside the outer edge of the rectus sheath, which contains the rectus abdominis (abdominal) muscles. The herniation occurs just below the level of the umbilicus (navel, belly button) and is also known as the hernia of the linea semilunaris.

Spigelian hernias usually develop in older age groups, often the 50s and 60s. The spigelian hernia has a narrow neck that predisposes the contents to adhesions and strangulation. Spigelian hernias are usually small and often start with pain in the area. The bulge of the hernia is not often seen as it lies beneath the aponeurosis of the external oblique muscle. Confirmation of the diagnosis may require ultrasound or CT-scan.

Spigelian Hernia Surgery (Repair)

Spigelian hernias are at risk of incarceration due to the narrow neck and surgical repair is therefore recommended once it is diagnosed. The hernia is approached through the external oblique aponeurosis and the sac is dissected. The contents of sac are reduced and the sac may be placed back into peritoneal cavity or excised. The defect is closed and muscle layers are closed. A mesh may be used to repair larger defects.

Obturator hernia

What is an obturator hernia?

Protrusion of the abdominal contents through the obturator canal is called an obturator hernia. The obturator membrane normally prevents such protrusions, but weakening of the obturator membrane can result in enlargement of the obturator canal allowing the formation of a hernial sac.

The intestines can pass into the sac and result in incarceration and strangulation. Intestinal obstructions can also result from obturator hernia. The hernial sac can press against the obturator nerve and result in pain along the inner side of the thigh. Abdominal imaging with a CT can be useful in confirming the diagnosis.

Obturator Hernia Surgery (Repair)

An obturator hernia is treated by open surgery or laparoscopic surgery. The hernia is approached from back and the hernial sac, its contents and extraperitoneal fat are reduced from the obturator canal. The obturator foramen is then carefully repaired with the help of a prosthetic mesh. The repair is done with extreme care to avoid any inadvertent injury to obturator nerve or blood vessels.

Lumbar hernia

What is lumbar hernia?

A lumbar hernia is a rare hernia that develops through the Grynfeltt’s (superior lumbar) triangle or Petit’s (inferior lumbar) triangle present in the posterior part of the abdominal wall. The herniation through superior lumbar triangle is more common than through the inferior triangle.

The superior lumbar hernia takes place through the triangle formed by the internal oblique muscle, the 12th rib and the spinal muscles. The inferior lumbar hernia protrudes between the latissimus dorsi muscle in the back, external oblique muscle in the front and the iliac crest below, completing the inferior lumbar triangle.

A lumbar hernia can sometimes be congenital. Incarcerations and strangulations are rare with a lumbar hernia due to the large neck. The best results in lumbar hernia repair are obtained with use of a prosthetic mesh.

Sciatic Hernia

What is sciatic hernia?

A sciatic hernia develops through the greater sciatic foramen of the pelvis. It is very rare and remains asymptomatic until late complications like intestinal obstruction develop. It is therefore difficult to diagnose.

A slow growing bulge in the gluteal region which may or may not be associated with sciatic nerve pain (due to nerve compression) may be suggestive of a sciatic hernia.

A reducible sciatic hernia can be repaired through a transgluteal approach after reducing the hernial sac contents. The defect can be repaired with or without a mesh. A transperitoneal approach is the better option if the hernia is strangulated or if intestinal obstruction is suspected. A prosthetic mesh repair is preferred in these cases.

Interparietal Hernia

What is interparietal hernia?

An interparietal hernia is one in which the hernial sac is positioned between the abdominal wall layers. Spigelian hernias are almost always an interparietal hernis. These hernias can also develop in patients who have undergone previous abdominal surgery.

Accurate diagnosis may require radioimaging with CT scan. In it not uncommon for patients to present with intestinal obstruction, only to be diagnosed with an interparietal hernia during surgery. Repair is usually done with a prosthetic mesh.

Perineal Hernia

What is perineal hernia?

Perineal hernias are caused by congenital or acquired defects where the hernial sac protrudes through the pelvic diaphragm. Acquired perineal hernias can occur after surgery in the perineal region. Rarely large perineal hernias can develop in old, multiparous women without any prior history of perineal surgery.

The hernial bulge gets larger on standing or sitting. The repair of perineal hernias can be done through abdominal approach or a combined abdominal-perineal approach. The contents and the sac are reduced and the repair of the defect is done with a mesh. Smaller defects may be managed without mesh.

Richter’s Hernia

What is Richter’s hernia?

This is a rare type of hernia in which a small part of the intestinal wall is strangulated within the hernia without any associated intestinal obstruction.

Internal hernia

What is internal hernia?

Protrusion of the intestinal loop through defects within the peritoneal cavity is called an internal hernia. An intestinal loop can enter the peritoneal recess (like the lesser sac) and become strangulated. The hernia remains asymptomatic until complications develop. Usually such hernias are diagnosed only during surgical exploration for an acute abdomen or intestinal obstruction.