Introduction Spinal dural arteriovenous fistulae (dAVFs) are uncommon lesions that often present with slowly progressive myelopathy. These shunts are located most commonly in the thoracolumbar region. A location in the cervical spine is considered exceedingly rare and has been reported most often in the context of subarachnoid hemorrhage. We report a series of five cases of upper cervical dAVFs and describe the clinical and angiographic characteristics of these lesions.

Materials and methods A review of interventional neuroradiology database identified five patients with upper cervical dural arteriovenous fistulae (CdAVFs). We performed a review of the patient charts, imaging studies, including digital subtraction angiography (DSA) and C arm CTs (when available), and the operative records. The imaging studies were reviewed by two neuroradiologists with experience in spinal angiography and interventions. We also performed a detailed review of the English literature on this entity.

Results Mean age of the patients was 61.6 years (range 45–75 years). There were three men and two women. Four of the five patients presented with subarachnoid hemorrhage (SAH) that could be attributed to the CdAVF. One patient had an incidental detection of the CdAVF while undergoing cerebral angiography for a ruptured left posterior communicating aneurysm. The fistulae were located at C1 or C2 level and supplied by C1/C2 radicular arteries. Small branches of anterior or lateral spinal artery were noted to supply the fistulae in four of the five patients. Embolization was performed in 3/5 lesions and was curative in one. Reduction in flow was accomplished in 2/5 but definitive cure using endovascular therapy was not possible due to small size of the feeder vessels and/or supply from ASA. One of these two patients has had microsurgical obliteration of the fistula. Two patients are being medically observed, one with incidentally detected fistula and another who refused microsurgical therapy.

Conclusion Upper cervical dAVFs may possibly be an under recognized entity. Approximately half of the reported cases have presented with SAH. Endovascular therapy is often difficult due to small size, eloquent nature and multiplicity of feeder vessels. Microsurgical therapy is also difficult but may offer a chance of complete obliteration in selected cases. In high risk cases, expectant management may be reasonable since the clinical course from the hemorrhage seems to be fairly benign and significant complications from SAH are uncommon. We advocate bilateral selective vertebral angiography (in addition to usual DSA workup) with the inclusion of their cervical segments in evaluation of any patient with hemorrhage in the region of the foramen magnum/upper cervical spine. These lesions have a higher chance of detection if the upper cervical spine is included in the imaging field of view.