Surgical Treatment of Irreducible Atlantoaxial Dislocation

Before surgery, a large weight traction of 1/6 body weight was used to determine the reversibility of atlantoaxial dislocation. After determining that it is difficult to restore the dislocation, a technique of anterior oral release and posterior fixation fusion was used for reduction, with sequential release of the longus colli and longus capitis, the anterior longitudinal ligament, the blitateral lateral mass joints, the contracted soft-tissue mass between the odotiod and the anterior C1 tubercle, and the peri-odontoid ligaments (i.e., the alar ligaments and the apical ligament), followed by posterior internal fixation and bone grafting was used between C1 and C2 lamina.

Preceding the surgical procedure, an assessment was conducted utilizing 1/6 weight traction to ascertain the reducibility of atlantoaxial dislocation. Upon confirmation of IAAD, the chosen approach involved the utilization of a specially designed spreader, tailored to the patient's atlanto-axial joint morphology. Upon entering the joint space, the spreaders were skillfully maneuvered to gently open the joint through rotational and prying actions. Subsequently, two cages, pre-filled with autogenous bone grafts, and designed with the appropriate angle and height, were meticulously placed between the Atlanto-axial joints via a posterior approach. This procedure facilitated direct distraction and reduction of the dislocated joint. In the final step of the surgical process, stabilization was achieved by securing the atlas and axis with screws and rods. This surgical approach was selected to address the unique challenges posed by IAAD, with the aim of achieving optimal patient outcomes.