Type A spinal epidural arteriovenous fistula initially classified as a spinal dural arteriovenous fistula: Persistent shunting after intradural disconnection and salvage
Source: PubMed Central Open Access, NCBI / U.S. National Library of Medicine
Background: Spinal epidural arteriovenous fistulas (SEDAVFs) are rare lesions characterized by shunting between arterial feeders and the epidural venous plexus. Type A SEDAVFs demonstrate secondary intradural drainage and may produce congestive myelopathy resembling a spinal dural arteriovenous fistulas (SDAVFs). We report a right L3 Type A SEDAVF initially classified and treated as a SDAVF, resulting in persistent epidural shunting and recurrent symptoms. st1 Case Description: A 73-year-old male presented with progressive gait instability, lower-extremity spasticity, and paresthesia. Conventional spinal angiography demonstrated a right L3 arteriovenous fistula with intradural perimedullary drainage, initially classified as a SDAVF. Three-dimensional rotational angiography (3DRA) was not performed initially. The patient underwent intradural coagulation and transection of the arterialized draining veins, with temporary improvement. Symptoms recurred 1 year later, and progressed over 6 months. Repeat angiography demonstrated persistent shunting with initial epidural venous plexus drainage and secondary retrograde intradural reflux, consistent with a Type A SEDAVF. 3DRA localized the fistulous point and showed no spinal cord arterial contribution from the embolized pedicle. Transarterial embolization with 33% n-butyl cyanoacrylate achieved complete occlusion. Gait, strength, and spasticity improved, with occlusion maintained at 6-month angiographic follow-up. st2 Conclusion: Typ
Abstract
Background: Spinal epidural arteriovenous fistulas (SEDAVFs) are rare lesions characterized by shunting between arterial feeders and the epidural venous plexus. Type A SEDAVFs demonstrate secondary intradural drainage and may produce congestive myelopathy resembling a spinal dural arteriovenous fistulas (SDAVFs). We report a right L3 Type A SEDAVF initially classified and treated as a SDAVF, resulting in persistent epidural shunting and recurrent symptoms. st1 Case Description: A 73-year-old male presented with progressive gait instability, lower-extremity spasticity, and paresthesia. Conventional spinal angiography demonstrated a right L3 arteriovenous fistula with intradural perimedullary drainage, initially classified as a SDAVF. Three-dimensional rotational angiography (3DRA) was not performed initially. The patient underwent intradural coagulation and transection of the arterialized draining veins, with temporary improvement. Symptoms recurred 1 year later, and progressed over 6 months. Repeat angiography demonstrated persistent shunting with initial epidural venous plexus drainage and secondary retrograde intradural reflux, consistent with a Type A SEDAVF. 3DRA localized the fistulous point and showed no spinal cord arterial contribution from the embolized pedicle. Transarterial embolization with 33% n-butyl cyanoacrylate achieved complete occlusion. Gait, strength, and spasticity improved, with occlusion maintained at 6-month angiographic follow-up. st2 Conclusion: Type A SEDAVFs may mimic SDAVFs when secondary intradural reflux dominates the angiographic appearance. Intradural draining vein interruption without elimination of the epidural shunt may leave persistent fistulous flow. Careful localization of the fistulous point and drainage sequence is essential, and 3DRA should be considered when conventional angiography does not clearly distinguish a dural from an epidural shunt. st3