A diaphragmatic hernia occurs when a tear in the muscles separating the abdominal and chest cavities allows abdominal organs to push up into the chest cavity. This is most commonly seen after the dog has experienced major trauma, often from a car accident. There are some genetic defects that also result in a diaphragmatic hernia. 

Patients with this issue will often present with breathing abnormalities, and X-rays or ultrasounds will usually show air or blood accumulating in the chest. In the event of a traumatic tear to the diaphragm, a herniorrhaphy (hernia repair surgery) is generally the only treatment that can resume function to the abdominal organs. This procedure must be performed by an ACVS board-certified veterinary surgeon. 

In most cases, diaphragmatic herniorrhaphy is used as part of an emergency surgery. X-ray, ultrasound, or advanced imaging techniques, if available, will be used to determine the extent of internal damage. The dog will likely be given oxygen supplementation for stabilization. If the dog is deemed able to withstand general anesthesia, it will be put under at this time. A needle may be put through the chest to drain air trapped outside of the lungs. 

An incision will then be made to the abdomen and the organs will be moved back to their original locations. All organs will have to be assessed for damage throughout the surgery, and some may need to be repaired or rotated. The lungs will be slowly expanded so that all tears may become visible. Once located, tears will be repaired with sutures. A tube will be used in the chest for ongoing removal of fluid, blood and air. Large sponges or pads will be used around the incision. After the diaphragm has been repaired, the abdominal opening may be closed using sutures or staples.

If done in an emergency situation, variable success rates are reported with diaphragmatic hernia repair surgery. Approximately 15% of dogs die while receiving this surgical procedure. Other mortalities may be related to other injuries in the body from the trauma. Better outcomes are seen if the animal is treated for shock prior to surgery. If the diagnosis is delayed, the prognosis becomes worse due to the formation of fibrous attachments on the improperly placed organs. Dogs who suffer from diaphragmatic hernias from birth carry a much better prognosis, and recovery is to be expected.

The dog will be kept in hospital for several days post-surgery. For the six to eight hours right after the operation, the dog will be closely monitored to ensure its breathing and temperature stay normal. The animal's position will also need to be periodically changed throughout this process. Feeding and air tubes may need to stay inserted for some time after surgery. The air removal tubes should be checked often as the dog heals. 

The dog may need further treatment for other injuries in the body. Pain medication will be administered as needed along with systemic antibiotics, sucralfate, and possibly famotidine. All activity should be limited for two weeks after the operation, at which point a follow-up appointment will be needed to evaluate how the dog is healing. 

This procedure is very expensive, ranging in cost from $2,500 all the way up to $10,000, depending on the severity of the injury and if other wounds are present. In emergency situations, there is often no alternative to a diaphragmatic herniorrhaphy other than euthanasia. If the procedure is being done on a dog with congenital defects, costs are on the lower end of the spectrum. Dogs exhibiting mild symptoms from these defects may not require surgical intervention.

The majority of complications related to a diaphragmatic herniorrhaphy involve issues with the anesthesia. In chronic tears, this can lead to reexpansion pulmonary edemas, which are life-threatening. If other severe injuries exist, survival may not be possible. For dogs with PPHD, there are no major differences in the long-term health of dogs who have received surgery versus dogs who have not. For this reason, a diaphragmatic herniorrhaphy may not be essential in dogs with genetic defects.

To prevent the need for a diaphragmatic herniorrhaphy, decreasing the chance of a traumatic incident occurring will greatly help. Keep your dog leashed at all times when not in fenced areas. Ensure your backyard is secure and that your dog cannot get out. Keep your dog away from busy roads or highways.

If your dog has been diagnosed with a congenital defect, do not breed the animal, in order to prevent the defect from passing on to other dogs. These defects of the diaphragm are often seen in Shar Pei and Weimaraner dog breeds and are often paired with deformations of the heart.