Foramen magnum decompression for treatment of caudal occipital malformation syndrome in dogs.

A method for foramen magnum decompression (FMD) in dogs with caudal occipital malformation syndrome (COMS) and results for 16 dogs are described. In brief, a dorsal approach to the caudal portion of the occiput and arch of the atlas was made, and a high-speed drill was used to remove a portion of the occiput in the region of the foramen magnum and the dorsal aspect of C1. The meninges that were exposed were removed or marsupialized to surrounding tissues. Foramen magnum decompression was performed in 16 dogs. No intraoperative complications occurred, and postoperative complications occurred in only 2 dogs after initial surgery and in 1 of these dogs after follow-up surgery. In both dogs, postoperative complications after the initial surgery resolved without additional treatment. One dog was nonambulatory tetraparetic after follow-up surgery and died of a suspected ruptured viscus 9 days after surgery. Four dogs developed evidence of scar formation at the surgery site and required additional surgery. Overall, 14 dogs survived, 1 died, and 1 was euthanatized. Clinical signs resolved in 7 of the 14 dogs that survived, improved in 6, and did not change in 1. Results suggest that FMD may be an effective treatment for dogs with COMS, especially if performed early in the course of the disease.