Dislocation Atlanto-axial

Rheumatoid disease is rarely complicated by a systemic vasculitis, which can involve the brain (Genta et al. 2006). Occasionally atlanto-axial dislocation causes symptomatic vertebral artery compression (Howell and Molyneux 1988). 

Scoville not only proposed a theoretical possibility but has proven it in clinical practive and reported two successful cases of atlanto-axial dislocation operated on via his originally advised route with Greenberg and Davey some 17 years later. 

The distance from the posterior aspect of the anterior arch of the atlas to the anterior aspect of the odontoid process is less than 3 mm in adults. A larger distance bespeaks atlantoaxial dislocation. The antero-posterior diameter of the spinal canal in the atlanto-axial region is 20-26 mm in men and 19-25 mm in women. According to Apuzzo et al. (1978), patients develop clinical symptoms when the anteroposterior diameter is less than 14 mm at C1-C2 level. 

In cases of atlanto-axial dislocation operated by the transoral route stabilisation of the spine is a crucial point. There are methods to achieve this fixation anteriorly. De Rougemount et al. (1966) placed a bone graft anteriorly from the ventral rim of the occipital bone to the level of the body of the axis. Thompson (1970) proposed the same fixation with bone chips after denuding the anterior surface of the bony structures. Estridge and... 

Dastur, D. K., Wadia, N. H., Desai, A. D., Sinh, G., 1965 Medullospinal compression due to atlanto-axial dislocation and sudden haematomyelia during decompression. Brain 88, 897—924. 

Hakuba, A., 1985 Transoral approach for atlanto-axial dislocation (in Japanese). Neurosurgeons 4, 231— 236. 

---