Surgical Obliteration of a Posterior Fossa Dural Arteriovenous Fistula Presenting with Exclusive Spinal Signs and Symptoms Caused by Spinal Cord Venous Hypertension.

Abstract

Vascular malformations in the dura of the spinal root sleeve in the thoracic or lumbar region can cause venous hypertension with resultant spinal cord edema and neurologic deterioration. However, occasionally an intracranial vascular malformation can have venous drainage into the spinal canal causing symptoms, signs, and radiographic appearance that can mimic spinal lesions. Herein, we present the case of a 73-year-old man who developed lower extremity weakness and loss of sensation. The patient initially underwent L4-L5 diskectomy elsewhere, but the symptoms progressed. Spinal magnetic resonance imaging revealed serpiginous vessels in the spinal subarachnoid space and spinal cord edema (Video 1). Diagnostic spinal and cerebral angiogram showed no evidence of spinal vascular malformations yet did reveal early venous shunting arising from the posterior fossa consistent with a dural arteriovenous fistula (dAVF). The venous drainage from this lesion was inferiorly directed into the spinal canal, causing venous hypertension of the spinal cord, which explained the patient's symptoms. An asymptomatic second dAVF of the petrous apex was also discovered. Surgical obliteration of both dAVFs in 1 sitting using a right far-lateral suboccipital craniotomy was planned. The dural drainage of each dAVF was identified and coagulated. Postoperative angiography confirmed complete obliteration of both dAVFs, and the patient's neurologic function improved shortly after surgery. This case highlights the importance of complete investigation of the spinal and cranial vasculature in the hunt for the cause of venous hypertension in the spinal cord.