[Torticollis and C1-C2 rotation subluxation. Apropos of a case. The value of a dynamic scanner and of a 3-dimensional scanner].

The authors report the rare and complex case of a girl who had been followed since the age of 3 years for hydrocephalus the cause of which was found only when she was 6-year old. The causative agent was a pilocytic astrocytoma of the cerebellum. On April 10, 1990, she underwent subtotal excision of the tumour, associated with radiotherapy. Four months later she developed an increasingly painful and irreducible torticollis which did not respond to tractions. Dynamic CT scans and 3-dimensional CT scans were performed in the fourth month and provided a diagnosis of right C1-C2 rotatory subluxation. There was no history of injury and no sign of inflammatory process. Rotatory subluxation is a very rare lesion difficult to diagnose, and few cases have been published, although the signs are those of classical torticollis in children. When medical treatment fails, often due to belated diagnosis, the only surgical treatment is uni- or bilateral C1-C2 arthrodesis. If the diagnosis can be made at an early stage, reduction of the rotatory luxation is usually easy and without consequences to the child. It is therefore recommended to perform a dynamic CT scan and a 3D CT scan as soon as possible in all children with lasting painful torticollis.