Spinal extradural arteriovenous malformations with parenchymal drainage: venous drainage variability and implications in clinical manifestations

Object Although nontraumatic spinal arteriovenous malformations and fistulas (AVMs and AVFs) restricted to the epidural space are rare, they can lead to significant neurological morbidity. Careful diagnostic imaging is essential to their detection and the delineation of the pathological anatomy. Aggressive endovascular and open operative treatment can provide arrest and reversal of neurological deficits. Methods The authors report on 6 cases of extradural AVMs/AVFs causing progressive myelopathy. Clinical findings, diagnostic evaluation, treatment, and outcome are discussed. Special consideration is given to the anatomy of the lesions and the operative techniques used to treat them. A review of the literature concerning extradural vascular malformations is also presented. Results All 6 cases of extradural AVMs had an extradural fistulous location with intradural medullary venous drainage. These cases illustrate progressive myelopathy through cord venous congestion (hypertension) that can be caused by an e...