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

The authors report on a 19-year-old man with an acquired tonsillar herniati on caused by a craniocervical junction injury in which serial magnetic reso nance (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 tonsil lar herniation as a complication of subarachnoid and epidural hemorrhage, p redominantly observed around the cisterna magna and upper cervical canal. R epeated MR images obtained over an II month period indicated the formation and acute enlargement of the syrinx. Ten months after the accident, the pat ient presented with sensory disturbance in both upper extremities and spast icity due to syringomyelia. He underwent craniocervical decompressive surge ry and duraplasty, which reduced the size of syringomyelia. The authors pos tulate that the patent central canal may play a role in determining the loc ation of a syrinx remote from a focus of cerebrospinal fluid obstruction.