Minimally Invasive Atlantoaxial Fixation with a Polyaxial Screw-rod Construct: Technical Case Report

Abstract

Posterior C1-C2 fusion with polyaxial screw and rod fixation has become an accepted means of atlanto-axial stabilization. We describe a novel technique for minimally invasive placement of C1 lateral mass screws and C2 pedicle screws for polyaxial screw-rod stabilization. The patient presented with a history of chronic neck pain, as well as a 6-month history of weakness and paresthesias involving her left hand. An Os Odontoideum was present on computed tomographic imaging of the cervical spine. Significant instability was noted on flexion-extension imaging, and magnetic resonance imaging demonstrated mild T2 signal change within the spinal cord. Under fluoroscopic guidance, serial dilators were passed through a 2.5 cm paramedian skin incision to allow placement of an expandable tubular retractor. The exposure was centered on the C2 lateral mass. After expansion of the retractor and further subperiosteal dissection, the C1 and C2 lateral masses were visible permitting placement of a polyaxial screw rod construct. This procedure was carried out bilaterally. Placement of C1 lateral mass and C2 pedicle screws using minimally invasive techniques is technically feasible.