The external carotid artery as a rare feeder of a spinal dural arteriovenous fistula causing cervical myelopathy: A review of the literature

INTRODUCTION: A causal relationship between SDAVF's and cervical myelopathy is exceedingly rare. 1–2% of these lesions are located at the craniocervical junction of which 12% are caused by arterial feeders from the external carotid artery. A correct diagnosis can be challenging with a high rate of initial misdiagnosis. RESEARCH QUESTION: Which aspects constitute the most important potential pitfalls in the diagnostic workup and treatment of SDAVF's with feeders from the external carotid artery causing cervical myelopathy? MATERIAL AND METHODS: We performed a PRISMA-guided review of the literature in which fourteen articles were included. We illustrate the diagnostic hazards through one of our own cases. RESULTS: SDAVF's at the cervical segment contain unique clinical and radiographic characteristics which differ from those elsewhere. Cervical myelopathy is caused by a SDAVF in 2.3% of cases. Pitfalls are numerous and diagnosis can be challenging, due to a broad differential diagnosis, potential isolated lower extremity involvement and absence of spinal cord edema on MRI. MR-alterations not always correlate with fistula localization. DISCUSSION AND CONCLUSION: A SDAVF should be part of the differential diagnosis in patients with subacute tetraparesis. When MRI shows signal alterations in combination with enlarged perimedullary vessels, a SDAVF should be suspected. Spinal angiography should include the vertebrobasilar system, as well as the internal and external carotid arteries. Early and adequate occlusion by means of an endovascular or neurosurgical approach of the draining radicular veins should be pursued. A multidisciplinary approach is key in the diagnostic workup and treatment of these patients.