How do incisional hernias develop?

Most surgical wounds from abdominal surgery heal well, leaving the abdominal wall just as strong as it was before the operation. But if the abdominal wall doesn’t grow back together tightly enough, the abdominal wall may be weakened near the scar. Then tissue or parts of organs might push through the gap that arises and bulge out.

The risk of incisional hernias is influenced by the following factors:

• The location of scar, the stitching material (suture), and the sewing technique used: Most incisional hernias occur after open abdominal surgery, where the abdomen was opened in the middle from top to bottom.
• Older age, other illnesses and wound healing problems: These can increase the risk too.
• Weight: Very overweight people are also more likely to develop incisional hernias because the pressure inside the abdomen is greater, which puts more strain on the scar tissue.

Depending on the size and the position of the surgical scar, about 5 to 15 out of 100 people develop an incisional hernia. Most incisional hernias occur in the first year after abdominal surgery.

What can you do to prevent them?

To lower the risk of incisional hernias, people are advised to do the following:

• Avoid straining your abdominal muscles too much in the first few months after surgery. But there is very little good-quality research on which kinds of strain are potentially harmful and which are not.
• Lose weight. The pressure inside the abdomen goes down as a result.
• Wounds are able to heal better in people who don’t smoke and who manage medical conditions like diabetes properly, so this also lowers the risk of incisional hernias.

Some people who have a major abdominal operation or incisional hernia surgery wear a special abdominal belt (corset) for a while afterwards, in order to help support their abdominal wall. But it isn’t clear whether abdominal belts actually help to prevent incisional hernias.

People who have a higher risk of incisional hernias can have a synthetic mesh put in their abdomen during abdominal surgery, as a preventive measure. The mesh strengthens the abdominal wall and can greatly reduce the risk of incisional hernias. But it can also cause problems such as chronic pain.

What are the treatment options for incisional hernias?

The opening of the hernia is sewn shut and usually covered with a synthetic mesh. This helps strengthen the abdominal wall. The risk of having another incisional hernia is much greater if no mesh is used.

The surgery can be carried out in the following ways:

• Open surgery: The doctor closes the hernia from the outside through a larger cut in the abdomen.
• Laparoscopic (minimally invasive or keyhole) surgery: The doctor inserts surgical instruments and a fine tube with a camera attached to it (a laparoscope) through several small cuts. The cuts are about 5 to 10 mm long.

If an incisional hernia occurs within the first few weeks after an abdominal operation, the hernia isn’t repaired immediately. This gives the abdominal wall time to recover. Incisional hernias are generally only repaired several months after the surgery that led to them was carried out.

Is open surgery or laparoscopic surgery better?

These two approaches provide similar levels of stabilization for the abdominal wall. As long as synthetic mesh was used, they also have the same risk of incisional hernias recurring.

One advantage of keyhole surgery is that the surgical wounds are less likely to become infected afterwards. It also allows you to leave the hospital sooner.

But the risk of complications might be a little higher with keyhole surgery if the surgeon doesn’t have enough experience. This is because it is harder to learn how to perform keyhole surgery compared to open surgery. So the surgeon’s level of experience will probably play a bigger role than the type of surgery that is done.

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You can read hospital quality reports to find out how often different hospitals in Germany perform hernia surgery.

What risks are associated with surgery?

Surgery can lead to injuries in the abdominal cavity. The wound may also become infected in the first few days after surgery. About 15 out of 100 people experience pain after surgery, but it often goes away after a few days or weeks. In some cases the pain becomes permanent, though. Possible causes of pain include nerves that were damaged, scar tissue sticking together, or the mesh being too tight.

Sometimes fluid builds up around the mesh after surgery. The fluid may have to be removed using a hollow needle (puncture aspiration).

About 5 out of 100 people develop another incisional hernia after having surgery to repair a hernia. People are advised to avoid lifting and carrying heavy objects. After keyhole surgery, that is recommended for six weeks and, after open surgery for three months because the scar is bigger.

Do incisional hernias always have to be operated on?

If incisional hernias don’t cause any problems and there's a low risk of complications, surgery isn't always needed. But this type of hernia often gets bigger over time, and there's a small risk that part of the bowel might become pinched. There is currently not enough good research to be able to say what the pros and cons of not having surgery are.

When deciding whether or not to have surgery, the patient’s age and other medical conditions play a role too. It is best to discuss your individual advantages and disadvantages of having surgery with a doctor.

When are incisional hernias more difficult to treat?

Because large incisional hernias are often very unpleasant, many people who have them want to have treatment. But large hernias are a lot harder to operate on than small hernias.

Many people who have large incisional hernias are very overweight, have weak abdominal muscles or have other medical conditions. This increases the risk of complications after surgery. The most suitable type of surgery will then depend on a range of individual factors. It can be a good idea for people in this situation to make an appointment at a specialized hernia center.

Women who would still like to have children are also in a special situation. Their abdominal muscles have to be able to stretch a lot during pregnancy to make room for the growing baby. Because synthetic mesh is less elastic than natural muscle tissue, doctors are concerned that women who become pregnant will have a greater risk of complications. Unfortunately, there is very little scientific research in this area.

Most women who have an incisional hernia can put off the hernia surgery until they're sure they don’t want to have any (more) children. When hernia surgery is necessary in women who might still have children, doctors tend to recommend not using a mesh. But then the hernia often returns during pregnancy.

Sources

• Al Chalabi H, Larkin J, Mehigan B et al. A systematic review of laparoscopic versus open abdominal incisional hernia repair, with meta-analysis of randomized controlled trials. Int J Surg 2015; 20: 65-74. [PubMed: 26074289]
• Borab ZM, Shakir S, Lanni MA et al. Does prophylactic mesh placement in elective, midline laparotomy reduce the incidence of incisional hernia? A systematic review and meta-analysis. Surgery 2017; 161(4): 1149-1163. [PubMed: 28040255]
• Dietz UA, Menzel S, Lock J et al. The Treatment of Incisional Hernia. Dtsch Arztebl Int 2018; 115(3): 31-37. [PMC free article: PMC5787661] [PubMed: 29366450]
• Payne R, Aldwinckle J, Ward S. Meta-analysis of randomised trials comparing the use of prophylactic mesh to standard midline closure in the reduction of incisional herniae. Hernia 2017; 21(6): 843-853. [PubMed: 28864937]
• Sanders DL, Kingsnorth AN. The modern management of incisional hernias. BMJ 2012; 344: e2843. [PubMed: 22573647]
• Sauerland S, Walgenbach M, Habermalz B et al. Laparoscopic versus open surgical techniques for ventral or incisional hernia repair. Cochrane Database Syst Rev 2011; (3): CD007781. [PubMed: 21412910]
• Schumpelick V, Junge K, Klinge U et al. Narbenhernie – Pathogenese, Klinik und Therapie. Dtsch Arztebl 2006; 103(39): A-2553 / B-2210 / C-2131.

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