Sciatic perineal hernia in two dogs.

A sexually intact, male Chihuahua and a spayed female poodle were presented with left perineal masses. The masses were identified as perineal hernias by rectal palpation. Surgical exploration of the perineal region in each dog revealed retroperitoneal fat protruding between the sacrotuberous ligament and the coccygeus muscle (sciatic perineal hernia). The hernias were repaired using modifications of the standard or internal obturator flap herniorrhaphies. The levator ani muscle was grossly and histologically normal in the Chihuahua and grossly normal in the poodle. No short- or long-term complications were reported in either case. The management of sciatic perineal hernia is similar to the more common caudal perineal hernia.