Spontaneous spinal epidural arteriovenous fistulae in neurofibromatosis type-1

BackgroundNF-1 is one of the most common autosomal-dominantly inherited genetic disorders with an incidence of approximately 1:3500. We report a case and review the literature to characterize spontaneous spinal AVF that occur in neurofibromatosis (NF-1).Case ReportA 51-year-old woman presented with NF-1 and progressive radiculomyelopathy. Angiography revealed an AVF terminating in a giant intraspinal epidural varix extending paraspinally through the C3/4 neural foramen. Trapping of the AVF attempted 18 years earlier prevented endovascular access for embolization, and vigorous bleeding made direct surgical resection impossible. Therefore, as palliation, arterial feeding collaterals were occluded, and surgically exposed tortuous veins were packed with coils. Laminectomies and partial resection of the epidural varix resulted in subtotal occlusion with clinical improvement.ConclusionThe spinal AVF associated with NF-1 appears to show dominant venous drainage to the intraspinal extradural and paraspinal venous plexus without evidence of intradural drainage. The vertebral artery is typically the origin of the fistula. A giant venous varix and numerous collateral feeders to the vertebral artery may give an AVM-like appearance. Clinically, the fistulae produce a syndromic triad including symptoms of NF-1, progressive radiculomyelopathy, and a bruit. Treatment is direct attack on the fistula by either surgery or embolization. If, however, a direct approach cannot be chosen, occlusion of feeding vessels combined with laminectomies can result in long-term symptomatic improvement.