Model Approaches for Hernia Repair
Research Models
Mark Johnson

Model Approaches for Hernia Repair

How models are helping to refine ways of treating a common abdominal condition that afflicts millions each year

A hernia occurs when an organ pushes through an opening in the muscle or tissue that holds it in place. They are most common in the abdomen, when intestines break through a weakened area in the abdominal wall.

Anything that causes an increase in abdominal pressure or a weakening of the abdominal wall could potentially cause a hernia. These examples include pregnancy, excessive weight lifting, obesity, even chronic coughing. Most hernias are not immediately life-threatening, but they don’t go away on their own and they can require surgery to avoid dangerous complications.

The only way to effectively treat a hernia is to have it surgically repaired, often by reinforcing the weakened tissue with synthetic mesh for long-term stabilization of the tissue. Like any medical device, the insertion of synthetic mesh can bring risks of complications, almost all of which require additional surgical intervention. Pain, infection, recurrence, adhesion, obstruction, and perforation are the most common complications associated with mesh.

While surgical mesh has come a long way in treating and preventing hernias, researchers and medical device developers are continually seeking more advanced and reliable procedures, such as in the material composition, design and implantation techniques.

Our lab has developed multiple models used for the evaluation of hernia treatments, including single-stage and two-stage hernia models. Single-stage hernia models are treated surgically immediately after the defect is developed. Two-stage hernia models allow the defect to mature prior to treatment, which is more indicative of how the hernia treatment would be applied clinically. Defects can be placed in various anatomical locations, including midline, off midline or inguinal, and studies can be customized based on the intended application of the hernia treatment, such as the minimally invasive laparoscopic technique or open surgery. Testing endpoints include biocompatibility, absorption rates, tissue integration, adhesion formation, burst strength, migration and more.

These techniques are most often performed in swine, as the size and anatomy of the pigs more closely replicate the biomechanics of a human abdomen. Various breeds of minipigs, particularly mature ones, are useful for longer-term studies because they have a reduced growth rate.

These models are a valuable tool in helping us better treat and perhaps prevent the millions of hernia repairs performed each year.