A craniocervical injury-induced syringomyelia caused by central canal dilation secondary to acquired tonsillar herniation. Case report.

The authors report on a 19-year-old man with an acquired tonsillar herniation caused by a craniocervical junction injury in which serial magnetic resonance (MR) images demonstrated patent and isolated segments of the central canal participating in the dilation and then formation of a cervical syrinx. The patient was involved in a motor vehicle accident; he developed tonsillar herniation as a complication of subarachnoid and epidural hemorrhage, predominantly observed around the cisterna magna and upper cervical canal. Repeated MR images obtained over an 11-month period indicated the for mation and acute enlargement of the syrinx. Ten months after the accident, the patient presented with sensory disturbance in both upper extremities and spasticity due to syringomyelia. He underwent craniocervical decompressive surgery and doraplasty, which reduced the size of syringomyelia. The authors postulate that the patent central canal may play a role in determining the location of a syrinx remote from a focus of cerebrospinal fluid obstruction.