Thoracotomy for repair of a large dorsal diaphragmatic hernia in an 18-year-old mare

An 18-year-old Arabian-mix mare was presented with a history of severe colic. Emergency exploratory celiotomy revealed diaphragmatic hernia, with a large rent in the left dorsal aspect of the diaphragm and large colon volvulus. Attempts to close the defect in the diaphragm in dorsal recumbency were unsuccessful. Therefore, a thoracic approach through lateral thoracotomy was elected, and a mesh was attached to the diaphragm using skin staples. While in dorsal recumbency, the mare suffered from significant respiratory acidosis. Thus, the mare was tilted into reverse Trendelenburg (30° head upward) and ventilation improved markedly. The mare recovered uneventfully, and was doing well 5 years after surgery.