Postanesthetic poliomyelomalacia in a horse.

A clinically normal horse was anesthetized preparatory to surgery in dorsal recumbency for removal of a retained testicle. After recovery from the anesthetic, the horse was weak in the hind legs, subsequently deteriorated and became unable to rise and died on the eighth day after surgery. On microscopic examination, extensive poliomalacia of the thoracic and lumbar spinal cord was found. It is postulated that this lesion was a result of ischemic insult to the spinal cord during anesthesia and several possible pathogeneses are discussed.