[Clinical Characteristics of Craniocervical Junction Arteriovenous Fistulas]

Craniocervical junction arteriovenous fistulas(CCJ-AVFs)are extremely rare lesions that may result in both subarachnoid hemorrhage(SAH)and myelopathy. Diagnosis of CCJ-AVF is difficult and may be delayed due to variable clinical features and a spectrum of neuroradiological findings. To elucidate the clinical characteristics of CCJ-AVF, we analyzed the clinical symptoms, neuroimaging findings, and the results of surgical treatment in five patients.

Among the five patients, four were diagnosed with dural AVFs, and the remaining patient was diagnosed with radicular AVF. Two of the five patients presented with SAH, and the rest presented with myelopathy. In both the SAH patients, the initial digital subtraction angiography(DSA)failed to reveal the AVFs, and a definitive diagnosis was made only after repeated DSAs. In two of the three myelopathy patients, the diagnosis was delayed because of nonspecific chronic neurological symptoms which resembled a thoracolumbar lesion. Four patients underwent shunt occlusion through direct surgery and demonstrated favorable outcomes. One myelopathy patient, however, demonstrated abrupt onset, associated with progressive neurological deterioration, which resulted in poor prognosis. The magnetic resonance imaging(MRI)findings, which included intramedullary high intensity on a T2 weighted image, flow void, and varix at the cervical cord, were specific for the myelopathy patients.

A thorough 4-vessel DSA study, including the cervical region, is mandatory for SAH patients whose clots are predominantly in the posterior fossa, and repeated DSA must be considered in cases of unknown origin. CCJ-AVF may cause myelopathy, with symptoms such as urinary dysfunction and/or paraparesis. Screening with a cervical MRI is useful for detecting CCJ-AVF in cases of myelopathy. Emergency radical treatment must be attempted for those patients demonstrating abrupt onset associated with symptoms of progressive deterioration, such as respiratory dysfunction or bulbar palsy.