Dural arteriovenous fistulae at the foramen magnum.

Spinal dural arteriovenous fistulae (DAVF) affect predominantly levels of the lower thoracic and lumbar segments; only 13 cases have been reported of DAVF at the foramen magnum. We present three surgically treated patients with DAVF at the foramen magnum. In none of our three patients could the site of the arteriovenous fistula be suspected from the clinical presentation. The clinical course varied from acutely developing signs and symptoms to a 10-year history of very slowly progressing symptoms. After neuroradiological diagnosis the patients were operated on direct microsurgical disconnection of the arteriovenous shunt via an enlargement of the foramen magnum and a hemilaminectomy of C1. DAVF at the foramen magnum may thus present with slowly to acutely progressing clinical symptoms and signs. Spinal angiographic examination should include the level of the foramen magnum if standard spinal angiography of thoracic, lumbar, and sacral segments is negative in suspected spinal DAVF since the nidus of the shunt can be situated remote from the level of neurological disorder. DAVF at the foramen magnum can be treated very effectively and with minimal surgical trauma by direct microsurgical disconnection of the shunt. This surgical procedure is indicated if embolization with glue is not possible or is unsuccessful.

Treatment strategies and results in spinal vascular malformations.

We report the treatment strategies and results of 70 patients with spinal vascular malformations. Forty-six had dural arteriovenous fistulas, 12 spinal cavernous angiomas, nine intramedullary angiomas, and three intradural arteriovenous fistulas. The diagnosis was established for cavernomas by magnetic resonance images only and in the other cases by selective spinal angiography in patients whose neurological deficits, myelograms or magnetic resonance images suggested the presence of a spinal vascular malformation. All patients had symptomatic vascular malformations and were treated microsurgically. Intramedullary angiomas were operated when embolization seemed too dangerous or impossible and when they had a contact to the dorsal or lateral surface of the spinal cord. All but one were completely resected. In one angioma a small ventral residual fistula area was left. Complete obliteration of all fistulas was achieved. The cavernomas were primarily resected. Apart from one postoperative permanent deterioration with a paresis of the left arm in a patient with an intramedullary angioma, 16 cases presented only a transitory worsening of their neurological status after surgery. The long-term outcome of all these patients was good. Five patients had to be operated on again: three patients showed difficult localizations of dural fistulas which were still visible in the postoperative angiograms, one patient suffered a spinal epidural hematoma, and another patient showed a cerebrospinal fluid accumulation. We conclude that spinal dural arteriovenous fistulas, small intradural fistulas, spinal cavernomas, and symptomatic spinal angiomas with contact to the lateral or dorsal surface can be treated microsurgically with low perioperative morbidity.

Spinal dural arteriovenous fistulas: a plea for neurosurgical treatment.

Spinal dural arteriovenous fistulas are the most common type of arteriovenous malformation involving the spinal cord, especially in middle-aged men. We report 21 patients with this malformation who had signs and symptoms of myelopathy. The diagnosis was established by selective spinal angiography in patients whose neurological deficits, myelograms or magnetic resonance tomographies suggested the presence of a spinal arteriovenous fistula. They were treated by microsurgical coagulation of the fistula nidus located in the dura and intradural division of the draining vein. Twenty patients improved neurologically following surgery, one remained unchanged. Complete obliteration of all lesions was verified by intra-operative microvascular Doppler sonography and in 3 cases by postoperative angiography. There were only a few minor and transient complications after surgery: one neurological deterioration where venous thrombosis was suspected, one cerebrospinal fluid accumulation and, in one case a transient wound healing impairment. Two patients had to be operated on again. In one case with difficult localization of a fistula at the L5/S1 level, the fistula was still visible in the postoperative angiogram. In another patient, a spinal epidural haematoma occurred a few hours after surgery. We conclude that microsurgical treatment of spinal dural arteriovenous fistulas is a safe, fast, simple and effective method of treating these lesions. However, recovery after surgical management was often incomplete because the diagnosis was established too late and the patient already presented with severe and long-lasting deficit. Thus, the main problem remains a diagnostic and not a surgical one.