Atlanto-Axial (C1–C2) Subluxation and Dislocation Chapter 3

Abstract Atlanto-axial dislocation is the loss of stability between C1 (atlas) and C2 (axis); according to the direction and plane of the dislocation, it can be divided into four types: anterior-posterior, rotatory (frequent in children), central, and mixed. If not diagnosed and treated in a timely and appropriate manner, atlantoaxial dislocation can cause permanent neurologic deficits and sagittal plane deformity. The treatment of atlanto-axial dislocation varies according to the severity of symptoms and the presence/absence of neurological involvement, and it ranges from conservative treatment (traction) to surgery (decompression and stabilization). Atlanto-axial dislocation in children is rarely caused by trauma; congenital abnormalities of C1–C2, space-occupying lesions, genetic disorders, and syndromes are significant risk factors for atlanto-axial dislocation in children.