Surgical stabilization of an occipitoatlantoaxial malformation in an adult dog.

OBJECTIVE: To report surgical planning, technique, and outcome of stabilization surgery in an adult dog with occipitoatlantoaxial malformation (OAAM). STUDY DESIGN: Clinical report. ANIMAL: A 19-month-old, 25.5 kg, male castrated, Shiba Inu. METHODS: Radiographic and magnetic resonance imaging were used to identify and characterize OAAM. Using a ventral approach to the cranial cervical region 2 cortical bone screws were inserted from the axis into the malformed atlas and occiput. RESULTS: Ambulation was conserved postoperatively. Within 4 weeks, neurologic examination was mostly normal except for decreased proprioception in the right pelvic limb. At 9 months, the dog retained an extended neck posture, but had no neurologic abnormalities. CONCLUSION: OAAM should be considered as a differential diagnosis in an adult dog with cervical myelopathy. Surgical fixation with cortical bone screws using a ventral approach can be successful.