Aortic foreign body resulting in ischemic neuromyopathy and development of collateral circulation in a cat

A cat evaluated for paraplegia had firm pelvic limb musculature and did not have femoral pulses. External wounds were not evident, but abdominal radiography revealed a round metallic foreign body on the midline ventral to the sixth lumbar vertebra. Angiography indicated stenosis or thrombosis of the aorta in association with the foreign body; collateral circulation arose from the fifth lumbar artery. Arteriotomy was performed to extract the foreign body and associated thrombi. Six weeks after surgery, angiography revealed blood flow in the abdominal portion of the aorta, but no evidence of obstruction or additional collateral vessels. The cat regained function of the pelvic limbs within 1 year after surgery. Ischemic neuromyopathy and paraplegia in cats is commonly associated with aortic thromboembolism. A thrombus is necessary to cause typical clinical signs, and vasoactive substances released by platelets in the thrombus are believed to cause ischemic neuromyopathy. Progression of the collateral circulation may allow for clinical improvement without surgical intervention.