This classification provides useful data for determination of the risk with each dural AVF and enables decision-making about the appropriate therapy.

Embolization was used to reduce the size of brain arteriovenous malformations (AVMs) prior to radiosurgical treatment in 125 patients who were poor surgical candidates or had refused surgery. Of these patients, 81% had suffered hemorrhage, and 22.4% had undergone treatment at another institution. According to the Spetzler-Martin scale, the AVMs were Grade II in 9.6%, Grade III in 31.2%, Grade IV in 30.4%, and Grades V to VI in 28.8% of the cases. Most embolizations were performed using cyanoacrylate delivered by flow-guided microcatheters. Radiosurgery was performed using a linear accelerator in 62 patients treated by the authors, and 34 patients were treated at other institutions using various methods. Embolization produced total occlusion in 11.2% of AVMs and reduced 76% of AVMs enough to allow radiosurgery. Radiosurgery produced total occlusion in 65% of the partially embolized AVMs (79% when the residual nidus was < 2 cm in diameter). Embolizations resulted in a mortality rate of 1.6% and a morbidity rate of 12.8%. No complications were associated with radiosurgery. The hemorrhage rate for partially embolized AVMs was 3% per year. No patient with a completely occluded AVM experienced rehemorrhage. Angiographic follow-up review of AVMs embolized with cyanoacrylate demonstrated a 11.8% revascularization rate, occurring within 1 year. It is concluded that after partial embolization with cyanoacrylate, the risk of hemorrhage from the residual nidus is comparable to the natural history of AVMs and that the residual nidus can be irradiated with results almost as good as for a native AVM of the same size.

Embolyx E, an occlusive and nonadhesive embolic agent, is capable of producing permanent occlusion of swine RMB with the development of mild intra- and perivascular inflammatory changes and no clinical complications. The slow endovascular delivery of DMSO produces no untoward angiographic, pathological, or clinical changes. A fast injection of DMSO causes endothelial necrosis and severe inflammatory response in the arterial wall. This embolic material seems to have appropriate biochemical, anatomic, and histopathological characteristics to be used in the treatment of cerebral arteriovenous malformations or vascular cranial base tumors.

No abstract

In this article, a detailed description of the normal arterial supply and venous drainage of the spinal cord is provided, and the role of catheter angiography and MR angiography in depicting the vascular anatomy of the spinal cord is discussed.

Onyx is a new nonadhesive liquid embolic agent that has been used to treat 23 patients at our institution with good results. Its nonadhesive nature and ease of use make it a promising agent in the future treatment of AVMs.

Object. The authors assessed clinical outcomes of patients with treated spinal dural arteriovenous fistulas (DAVFs) and investigated prognostic factors. Methods. Thirty consecutive patients with spinal DAVFs were treated at the authors' institution during the past 15 years: seven underwent surgery; seven underwent surgery after failed embolization; and 16 underwent embolization alone. The outcomes of gait and micturition disability were analyzed. Follow up averaged 3.4 years (range 1 month–11.8 years). Age, duration of symptoms, pre- and postintervention magnetic resonance (MR) imaging findings, and preintervention disability were correlated with outcome. Seventeen patients (57%) experienced improved gait, 12 (40%) were unchanged, and one (3%) was worse. In 11 patients (37%) micturition function was improved, in 15 (50%) it was unchanged, and in four (13%) it was worse. Gait disability, as measured by the Aminoff—Logue Scale, was significantly improved after treatment, from 3.4 ± 1.4 (average ± standard deviation) to 2.7 ± 1.5 (p = 0.007). Mean micturition disability scores decreased, but not significantly, from 1.9 ± 1 to 1.6 ± 1.1 (p = 0.20). Preintervention gait disability was not associated with improvement except for patients with Aminoff—Logue Scale Grade 4 disability (eight of nine improved; p = 0.024). For patients treated within 13 months of symptom onset, mean micturition disability decreased (p = 0.035). No association was found between clinical improvement and age, a symptom duration less than 30 months, or pre- and postintervention MR imaging—documented spinal cord edema. Conclusions. Spinal DAVF treatment significantly improved patients' mean gait disability score by almost one grade at last follow up. The mean micturition disability score was not significantly improved, unless treatment was performed within 13 months of symptom onset. Longer and more uniform follow-up study is needed to determine if improved and stabilized clinical outcomes are sustained.

Spinal dural arteriovenous fistulas (SDAVF) are a rare pathologic entity with a diverse and often misleading clinical presentation. While digital subtraction spinal angiography remains the gold standard, recent advances in noninvasive vascular imaging have improved the diagnosis of SDAVF. As this condition can result in permanent spinal cord injury, all patients require treatment, which consists of surgical or endovascular occlusion of the fistula. Failure to recognize and treat SDAVF in a timely fashion can result in irreversible neurologic disability, including myelopathy, lower extremity weakness and bowel, bladder and sexual dysfunction. This article reviews the clinical features, pathogenesis, radiographic features and current treatment strategies for these complex lesions.