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

Abstract

<jats:sec> <jats:title>Object</jats:title> <jats:p>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.</jats:p></jats:sec> <jats:sec> <jats:title>Methods</jats:title> <jats:p>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.</jats:p></jats:sec> <jats:sec> <jats:title>Results</jats:title> <jats:p>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 extradural nidus or fistula. In 4 cases, a large epidural lake was identified on angiography. At surgery, the epidural lake was obliterated and medullary drainage interrupted. All patients had stabilization of their neurological deficits and successful obliteration of the AVM/AVF was obtained.</jats:p></jats:sec> <jats:sec> <jats:title>Conclusions</jats:title> <jats:p>Extradural AVMs and AVFs are a poorly described entity with published clinical experience limited to sporadic case reports and small series. Although these lesions have a purely extradural location of arteriovenous shunting and early venous drainage, they can be responsible for acute and progressive neurological symptoms similar to those caused by their dural-based intradural counterparts. With careful imaging recognition of the pathological anatomy, surgical and endovascular techniques can be used for the treatment of extradural AVMs affording effective and durable obliteration with stabilization or reversal of neurological symptoms. Venous drainage directly correlates the pathologic mechanisms of presentation. Specific attention must be paid intraoperatively to the epidural lake common to both variants so that recurrence is avoided.</jats:p></jats:sec>

Comparative analysis of spinal extradural arteriovenous fistulas with or without intradural venous drainage: a systematic literature review

“…[2][3][4][5][6][7][8][9][10]12,13,[15][16][17][19][20][21][22][23]25,27,[29][30][31][32] These cases were divided into 2 groups: those with and those without intradural venous drainage, 22 and 23 cases respectively (Tables 1 and 2). …”

“…3,6,7,9,10,13,16,[21][22][23]25 Venous congestion is presumed to be a primary cause of myelopathy in these patients, which is similar to cases of dural AVFs.…”

Endovascular Treatment of Spinal Arteriovenous Lesions: Beyond the Dural Fistula

“…Neurologic symptoms occur by mass effect on the spinal cord and/or nerve roots from the enlarged draining veins, arterial steal if there is diversion of a large quantity of blood from the ASA, and/or by venous hypertension if the shunt drains though spinal veins causing resistance to venous outflow. Epidural AVFs are primarily described in case reports and small case series, [18][19][20] with the cervical spine representing the most common location. 21 The arterial feeders that supply the epidural AVF are usually branches of the costocervical and thyrocervical trunk; the vertebral, intercostal, and lumbar arteries; and arteries that supply the sacrum and the pelvis.…”

Cervical Spinal Epidural Arteriovenous Fistula with Coexisting Spinal Anterior Spinal Artery Aneurysm Presenting as Subarachnoid Hemorrhage—Case Report

“…Ó 2014 by National Stroke Association Spinal epidural arteriovenous fistulas (AVFs) are rare cervical spine vascular lesions, and they are generally thought to present with benign clinical symptoms, such as radiculopathy. [1][2][3] In some cases, spinal epidural AVF can cause acute paraplegia due to reflux into medullary veins with venous congestion. [4][5][6][7] In patients with craniocervical dural AVF, subarachnoid hemorrhage has been reported to occur because of a direct venous drainage pattern in an intracranially or intramedullary fashion.…”