Lateral Approach for Cervical Lesions Located at Atlanto-Axial Level

Abstract

In the present paper, a lateral approach to the lesions located atlanto-axial region is described. We adopted this approach in seven cases. Four cases had dumbbell type neurinoma, two had large pannus formation by RA compressing the upper cervical cord, and one had non-reducible atlanto-axial dislocation. For dumbbell type neurinomas, the lateral approach enabled us to identify the location of vertebral artery at an early stage of the operation and to expose easily the interface between the tumor and the cord. As to the extradural lesions, by drilling the lateral atlanto-axial joint or lateral mass, we could approach the ventral extradural areas without difficulty. In a case with non-reducible atlanto-axial dislocation, the two thirds of the odontoid process was located posterior to the vertebral artery and the atlanto-axial interlaminar space was wide due to C1 occipitalization. These anatomical characteristics made the lateral approach to the odontoid process easier. Postoperatively, unilateral drilling of the lateral mass did not induce instability as reported before. However after drilling of the lateral mass and odontoidectomy, we had to add posterior fusion with instrumentation. In all cases, follow up results were satisfactory and this operative approach can be recommended in cases with intradural or extradural atlanto-axial ventral lesions.