Microsurgical Disconnection of Foramen Magnum dAVF

Dural arteriovenous fistulas (dAVFs) are acquired pathological shunts within dural folds that allow direct communication between arterial and venous systems without intervening nidus. They are classified based on venous drainage pattern and presence/absence of cortical venous reflux (CVR), a surrogate of venous hypertension that is an independent predictor of risk of intracranial hemorrhage. Ventrally located high-risk dAVFs at the foramen magnum are technically difficult to microsurgically disconnect. We present technical nuances for surgical management of such complicated vascular malformations. The patient was a 59-year-old man with vertical gaze paresis, no history of headache, and no diplopia, sensorimotor deficits, or lower cranial nerve paresis. MRI and digital subtraction angiogram demonstrated a ventrally located foramen magnum dAVF fed by multiple small arterial feeders from the vertebral artery (VA) at the junction of V3 and V4 segments. It was draining into a large ectatic anterior pontomesencephalic vein, which drained into the straight sinus and right transverse sinus. There was marked CVR into the cortical cerebellar veins and anterior spinal vein suggestive of Type II Borden classification dAVF. After failed endovascular treatment, the patient underwent a right far-lateral transcondylar microsurgical approach and VA transposition for fistula disconnection. The abnormal dural arterial feeders from the VA were coagulated, and the arterialized pontomesencephalic vein was coagulated and disconnected from the dural VA feeders. Complete obliteration of the fistula was confirmed using intraoperative indocyanine green angiography. Postoperative angiogram revealed complete obliteration of the fistula with no evidence of persistent CVR, and he was discharged with uneventful follow-up.

Видео Microsurgical Disconnection of Foramen Magnum dAVF канала NEUROSURGERY Journal