Spine fusion for atlanto-axial instability.

A follow-up study was done on fifty-seven spine fusions for atlanto-axial instability, classified as Type I - deficient odontoid (twenty-eight patients), Type II - deficient ligaments (twenty-three patients), and Type III - rotatory fixation (six patients). The average age of the patients at the time of the fusion was thirty years, and half had had significant trauma. Symptoms had been present for an average of 12.3 months before fusion. Preoperatively pain was the predominant complaint in twenty-nine; neurological complaints, in twenty-four; and instability in the rest. Of the forty-six Gallie fusions, there was one non-union and of the eleven occipitocervical fusions, two non-unions. Follow-up averaging 4.2 years revealed resolution of symptoms in almost all patients.