Family doctor

What is a hernia?

A hernia occurs when part of the abdominal contents, contained in its lining, pushes through a defect in the muscle wall, much in the way an inner tube pushes through a split in the tyre casing of a wheel. The problem is a mechanical one, requiring a mechanical solution i.e. surgical repair. Most commonly repair is sought because the hernia is causing discomfort. Some hernias cause no symptoms at all, so the need for repair is reduced. However there is a "bottom line" risk that intestine may become trapped in the hernia and strangulate, a situation which requires urgent surgical attention. This is not so common these days, probably because most hernias are repaired early on.

Inguinal hernias occur because of a slight design defect the body has in the groin, and are not the result of individual weakness or the body "falling apart". They tend to occur more commonly in people involved in heavier physical activity or work, but people of all walks of life and ages can develop hernias. Only a minority develop their hernias as a result of a specific event or injury. About 95% of inguinal hernias occur in men. They are classified as direct or indirect according to the specific site through which they protrude. A femoral hernia protrudes through the femoral canal in the groin, very close to the site of an inguinal hernia. Incisional hernias occur through a weakened scar/previous incision elsewhere in the abdominal wall.

Treatment

Traditionally, an inguinal hernia is repaired by an "open" technique involving an incision in the groin some 10-14 cms long, extending through muscle layers, so that the defect in the muscle can be isolated and sutured closed - to use the tyre analogy, the tyre casing is repaired. A more recent form of open repair employs nylon mesh to patch the defect on its outer aspect.

The laparoscopic technique of repair avoids the large skin and muscle cut, as well as the closing of the defect with sutures under some tension. This way postoperative pain is decreased, and earlier return to discomfort-free movement is possible.

The operation is done within the extraperitoneal space which is developed from the level of the umbilicus via a small (10 mm) incision. Using the split tyre casing analogy, this space is between the peritoneum/inner tube and muscles layers/tyre casing. A narrow telescope (the laparoscope) is passed into this space and connected to a television monitor providing a magnified image of the hernia defect. Through two smaller (5 mm) incisions, long narrow instruments are used to repair the hernia by placing a patch of nylon mesh over the exposed defect, fixing it in place with a series of titanium screws, i.e. a patch is fixed to the inner aspect of the tyre casing, between the inner tube and the split casing. The mesh is held very firmly by the screws, and on account of the mechanics of the repair it is felt that an immediate return to full normal activities and work is permissible without fear of inducing recurrence. In practical terms, this is usually achieved around seven days following surgery.

Results

Laparoscopic repair is technically more demanding than the traditional approach, but provided attention is applied to detail, damage to intestine or major blood vessels should not occur. Although foreign material (the nylon mesh) is left in the body, problems with infection around this have not been described. Bowel obstruction has been described following laparoscopic hernia repair, but the risk is considerably reduced with the extraperitoneal approach. With any form of hernia repair there is a recurrence risk, and it is important to understand that the long term results of the laparoscopic repair are not certain, as no long term studies have yet been completed. With open repair, the recurrence rate has traditionally been around 5% at five years, increasing to approximately 14% long term. My series is being carefully audited, and at this stage results are very promising, with recurrence rates running at < 0.2% (two recurrences in over 1100 repairs).

With the laparoscopic approach, herniae on both sides can be repaired at the same time with little increased discomfort and no increased risk of recurrence (which is associated with simultaneous bilateral open repair). It is an excellent technique for repairing hernias that have recurred following an open repair. Postoperative urinary retention, which can be a problem following open repair, is a rare occurrence after laparoscopic repair, even in elderly men with significant urinary outflow impairment. The technique is growing in popularity, and most centres in New Zealand now have at least one surgeon performing laparoscopic hernia repairs.