Ventral fixation of chronic atlanto-occipital luxation in a dog.

A 4·5-year-old male Australian Kelpie was presented for evaluation of ambulatory tetraparesis and neck pain of five weeks duration. Atlanto-occipital luxation was diagnosed by computed tomography. The joint was unstable following closed reduction, and a ventral surgical approach to the cranial cervical spine and occiput permitted manual reduction and stabilisation of the atlanto-occipital joint. The thickened joint capsule and articular cartilage were removed to promote AO arthrodesis. Eight cortical screws, inserted into the occipital condyles and C1, were embedded in polymethylmethacrylate to stabilise the atlanto-occipital articulation. The dog recovered uneventfully after it was placed in a neck brace and rested for six weeks. Neurologic examination at six weeks was normal and the dog returned to normal farm work 12 weeks after surgery.