Abdominal Wall Hernia
Abdominal wall hernias are classified according to the defect or the cause (primary, incisional, recurrent). Incisional hernias arise after a surgical incision due to weakness secondary to the surgery. Recurrent hernias are those that recur following surgical repair.
Primary abdominal wall hernias include groin hernias (inguinal and femoral), hernias around the umbilicus, epigastric hernias (between the umbilicus and the lower part of the sternum) and rare hernias such as obturator, spigelian and lumbar hernias.
Large abdominal wall hernias, especially those arising after surgery, can be very complex and difficult to fix. Repair may be done laparoscopically or open or a combination of both (hybrid). It usually requires a large mesh (see below) and may require incision and mobilisation of the abdominal wall muscles on the side allowing to move centrally to bridge the hernial defect (component separation).
A mesh is a piece of synthetic (or less commonly biological) material which is used to support the weak tissues around a hernia. The hernial defect is usually closed (under minimal tension) and mesh is place either underneath (sublay) or on top (on-lay) of the closed defect. If the defect cannot be closed, the mesh may be used to bridge the gap (in-lay). The best type of repair is one where the mesh is in the sublay position.
Before repairing a very large abdominal wall hernia, the side muscles may need to be relaxed a few weeks before with an injection of Botulinum toxin A (Botox) which is done under ultrasound guidance.
Not all abdominal wall hernias can be or should be repaired. It depends on the patient’s medical condition and other factors such as the size of the defect, previous repairs, the amount of tissue within the hernial sac compared to what is left inside the patient’s abdomen. This should be assessed on a case by case basis.