An alternate method for posterior fixation in anterior and inferior atlanto-axial dislocation.

A modification of common methods is described for fixation of anterior and inferior atlanto-axial dislocation (AAD and IAD). In AAD a wire is passed around the atlas arch and knotted around the spinous process of the axis in a way that a figure 8 arrangement is achieved as seen in the lateral view. In IAD a wire is passed through holes in the occiput and knotted around the spinous process of the axis. A rectangular bone graft is inserted between the occiput and the spinous process of the axis, thus preventing further inferior dislocation. In both methods methyl methacrylate and bone grafts are as a rule added for further long-time stabilization. The methods have been used in 15 cases of AAD and in three cases of IAD. On radiologic examination with attention focused on the immediate postoperative fixation the follow-up time has been three months. The long-time results of fixation have been recorded with a follow-up time of six years. The fixation proved to be satisfactory in 14 patients with AAD and in the three patients with IAD. The clinical results were good in the 14 patients with AAD and in the three with IAD.