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.