Unreduced atlantoaxial dislocation locked with a combined lateral mass fracture

Abstract

Traumatic bilateral rotatory subluxation of the atlantoaxial joints is a rare injury, and reduction is generally achieved spontaneously and with ease by traction therapy. On the other hand, the pathophysiology of rotatory atlantoaxial subluxation is not well defi ned, but it is common in children and is a consequence of specifi c anatomical features. The joint surface of the lateral mass is shallower and more horizontally oriented in children, and the relative elasticity of ligaments allows a greater degree of deformity before failure. However, traumatic atlantoaxial rotatory subluxation in adults is rare owing to the unique biomechanical features of the C1/2 articulation and the likely lethality of such an injury before presentation at a trauma center. Atlantoaxial bilateral rotatory dislocation is uncommon, particularly in adults, and most of the reported cases have been in adults who have undergone surgery. To our knowledge, nonoperative management has been reported in only two such adult cases, and in both reduction was achieved by simple manipulation (Table 1). The authors report a case of type I traumatic rotatory atlantoaxial injury in which complete reduction was successfully achieved using closed maneuvers after failure to achieve reduction by closed traction due to locking of the dislocated atlas by a combined lateral mass fracture of the axis.