Remote Thoracic Myelopathy From a Spinal Dural Arteriovenous Fistula at the Craniocervical Junction: Case Report and Review of Literature

Background: The craniocervical junction is a rare location for spinal dural arteriovenous fistulas (dAVFs). Typically, fistulas at this location present with findings related to intracranial cortical venous reflux or cervical myelopathy. We present a case of craniocervical junction dAVF with isolated clinical and radiographic findings of thoracolumbar myelopathy.

Case description: A 54-year-old man presented with subacute onset of lower extremity weakness, paresthesias, and gait dysfunction. Routine spine magnetic resonance imaging demonstrated edema of the conus medullaris and distal thoracic spinal cord and prominent dorsal venous flow voids, suggestive of a thoracolumbar dAVF. Spinal angiography performed at an outside institution failed to demonstrate a fistula. Noninvasive spinal angiographic imaging with time-resolved magnetic resonance angiography (TR-MRA) performed at our institution was able to demonstrate presence of the fistula at the craniocervical junction. Subsequent cerebral angiography identified feeding vessels arising from the posterior meningeal artery and ascending pharyngeal artery on the right side. The fistula was successfully embolized with onyx embolic material, with rapid resolution of his clinical symptoms.

Conclusions: Isolated lower extremity myelopathic symptoms are a rarely reported finding in patients harboring craniocervical junction dAVFs. At our institution, noninvasive imaging with TR-MRA is routinely used to aid localization of dAVFs. This results in decreased contrast dose and radiation exposure, and inclusion of the cervical spine should be performed when thoracolumbar imaging fails to identify a dAVF prior to proceeding to invasive angiography.