These are the most common types of abdominal hernias, seen in approximately 2% of foals. Horse with umbilical hernias will have a bulge on the bottom of the body wall that is located at the umbilical remnant. These hernias can vary in size, from less than an inch in diameter to several inches in diameter. The hernia usually contains portions of the intestinal tract that will move in and out of the hernia sac. When you palpate, or feel the hernia, the contents within the hernia can be pushed back into the abdomen and a fibrous ring can be palpated at the margin of the hernia sac. Hernias less than 1 inch can resolve on their own, if the contents are pushed back into the abdomen frequently. Surgical treatment of small hernias is needed if the size of the hernia has not improved when the foal is 4 months old. Large hernias, greater than 2 inches in diameter, need surgical treatment.
Treatment of umbilical hernias, at Texas A&M, are done with the foal under general anesthesia and in dorsal recumbency. An incision is made around the hernia and the hernia sac is removed, taking extreme care not to injure the abdominal contents within the hernia. Generally the abdominal contents adjacent to the hernia are examined and then the incision in the abdominal wall is sutured closed, along with the subcutaneous tissue and skin. Following surgery the horse will need 1-3 months of confinement (stall rest, confinement to a small pen or small trap). Younger horses with smaller hernias will need less confinement following surgery, than older larger horses with large hernia. Repair of these hernias will result in a good cosmetic result and athletic potential.
Complications with umbilical hernias include strangulation of intestine within the hernia, which can result in emergency surgery to remove the strangulated intestine and repair of the hernia. A foal may tear their body wall following surgery which can result in another abdominal hernia that will probably require surgical repair.
Although rare, this type of hernia can develop following abdominal surgery (colic surgery, inguinal hernia repair, ect). The sutures holding the edges of the abdominal wall together will become weak secondary to an infection developing in the incision and result an abdominal incision hernia.
Treatment involves putting the horse on systemic antibiotics for several weeks to resolve the infection in the incision, along with putting an abdominal belt on the horse to help support the abdominal contents and preventing the hernia from getting bigger. A period of 4-6 months is need from the time the hernia develops until the time surgical repair is attempted. During this 4-6 month period the infection in the hernia will resolve and the edges of the hernia will gain strength secondary to the production of scar tissue. Once the infection is resolved and the margins of the hernia have developed an adequate amount of scare tissue, surgical repair can be performed with a mesh for large hernias or by directly suturing the hernia margins together in the case of smaller hernias. Prior to surgery the horse will be held off food for at least 48 hours to decrease the amount food material within the large colon and make the hernia repair easier intra-operatively and post-operatively.
Horses that have abdominal incision hernias repaired have a good prognosis for return to normal athletic function. Cosmetically there are minimal signs of a hernia following surgery.