Eighteen patients who had a fracture of the atlas were evaluated
clinically and by computed axial tomography an average of forty-six months
(range, two to 164 months) after injury. The purpose of the evaluation was
to determine the effect of the pattern of the fracture, the quality of
osseous healing, and the method of primary immobilization on the long-term
outcome. Three (17 per cent) of the patients had a non-union, and two of
them had a poor clinical result. These two patients had had a unilateral
comminuted fracture--that is, one fracture that was anterior and one that
was posterior to the lateral mass, with an associated osteoperiosteal
avulsion of the transverse ligament on the same side of the ring of the
atlas. Six (33 per cent) of the eighteen patients had an osteoperiosteal
avulsion of the transverse ligament. The avulsions usually progressed to
osseous union. Rupture of the mid-substance of the transverse ligament was
uncommon. No patient had a neurological deficit or late neurological
sequelae that were directly attributable to the fracture of the atlas.