If the hernia is easily reduced, determining the location of the hernial ring is possible. Reduction of the hernia may be assisted by elevating the hindquarters while the animal is in dorsal recumbency. When pressure in the caudal portion of the abdominal cavity is thus reduced, the hernial ring may be palpable.
If it's difficult or impossible to reduce the hernia because of incarceration or strangulation of intestine or growth of a fetus after herniation of the uterus, the diagnosis becomes more difficult. The swelling may be confused with a mammary tumor, cyst, hematoma or abscess.An abscess is usually warm and accompanied by fever and leukocytosis. There are usually signs of pain when an abscess is palpated and the swelling is nor so freely movable as that of a hernia, Cysts and hematomas are not warm and usually take considerable time to develop. These are most easily diagnosed by palpation,' they are finn and may be lobulated or nodular. Lipomas in the inguinal region may be difficult to differentiate from a hernia, however It mast be kept in mind that a mammary gland or tumor may conceal a small hernia.
Exploratory puncture and aspiration of the swelling contents have been advocated as a diagnostic measure, but this should be done with caution.
Radiography is helpful to differentiate intestine, gravid uterus, or bladder in the hernial sac, Barium contrast material is helpful if the digestive tract is involved. When the herniated uteruses gravid and in late gestation, the fetal skeleton will be visible on scout films, If gestation has been less than 43 days, a lobulated fluid density will be apparent.
When the bladder is involved, signs of cystitis are associated with the hernia. After administration of 10% Sodium Iodide or air, a cystogram will reveal the presence of the bladder in the sac a decrease in the size of the hernia may be observed following urination or urinary bladder catheterization. Although some inguinal hernias may be readily diagnosed, in others the bulge in the inguinal region may be so insignificant as to defy detection, Only a small portion of the intestine may be incarcerated in the inner ring. These animals are presented with signs of intestinal obstruction. The cause of such a radiographically demonstrable obstruction may be ascertained only by exploratory laparotomy.
Ventral midline approach is used for all inguinal hernias allowing utilization of both inguinal rings and repair of bilateral hernias through a single incision. In addition, this incision maybe extended cranially without disruption of the mammary tissue or its' blood supply.
The incision is made from the cranial brim of the pelvis and brought cranial until adequate exposure of the sac is accomplished. Undermining of the mammary tissue and lateral retraction allows for exposure of the inguinal ring and sac. Blunt dissection frees the sac from the subcutaneous tissue. The hernial sac is opened and inspected Adhesions between the sac and viscera are removed and sac contents are returned to the abdominal cavity.
Often enlargement of the inguinal ring is accomplished in order to ease hernial reduction. Should bladder be included, aspiration simplifies the procedure.
After organ replacement, the sac is trimmed at the margins of the inguinal ring and the hernial ring sutured with simple interrupted (2-0) stainless steel.
Inspection is made of the opposite inguinal ring, vaginal process removed and inguinal ring sutured closed. Mammary tissue is replaced and a penrose drain inserted. Routine closure of skin follows.
Post-operative care includes an abdominal wrap bandage which eliminates dead space and helps the comfort of the patient. Drains are removed 3 - 5 days post-operatively.
This condition is rare but deserves mention because of the extreme caution required for its surgical reduction. Statistical evidence of breed or sex susceptibility is not available, The diagnosis is based on the presence of an enlargement of the femoral canal on the medial side of the thigh. The femoral and inguinal hernia can be difficult to differentiate. By standing the animal on its hindlimbs an inguinal hernia will be dorsal and medial to the pelvic brim. It tends to pass ventrally and medially toward the scrotum and is above the inguinal ligament. With a femoral hernia, the swelling is ventral to the inguinal ligament and ventral and lateral to the pubic brim. The technique used for repair of femoral hernias is almost identical to that used for inguinal hernias, except that care must be taken to prevent injury to the important femoral vessels.