Intracranial dural arteriovenous fistula treatment

If you don’t completely eliminate a dural arteriovenous fistula (spinal or intracranial) it will come back!.

Radical treatment is to obliterate the draining veins in any treatment modalities including endovascular treatment or surgical treatment. Radiosurgery is the last choice. Transvenous embolization plays the main role in the DAVF of the cavernous sinus and anterior condylar confluence. Transarterial embolization with Onyx has dramatically improved the obliteration rate of the transverse-sigmoid, superior sagittal sinuses, and other non-sinus lesions. Understanding of the functional microvascular anatomy is mandatory, especially in the transarterial liquid injection (Onyx and NBCA). Surgical treatment in the DAVF of the anterior skull base, craniocervical junction, cerebellar tentorium region, is a safe and radical treatment. Postoperative follow-up is necessary from the viewpoint of chronological and spacial multi-occurrence of this disease ¹⁾.

Lesions with cortical venous drainage should generally be treated. Lesions without cortical venous drainage should be followed radiographically and clinically (2% may evolve to develop cortical venous drainage). A change in a bruit (either worsening, or disappearance) should prompt restudy.

1. Cortical venous drainage with resultant venous hypertension can produce intracranial hypertension, and this is the most common cause of morbidity and mortality and thus the strongest indication for intracranial dural arteriovenous fistula treatment.

2. neurologic dysfunction

3. hemorrhage

4. orbital venous congestion

5. refractory symptoms (headache, pulsatile tinnitus).

Advocated by some, the thrombosis rate of ≈ 22% and clinical improvement rate of 33% ²⁾ may mimic the natural course. Patients are advised to compress with the hand that would be affected by ischemia if it were to occur (e.g. with a left-sided DAVF, the right hand should be used to compress the left carotid artery). That way, the hand would fall away if ischemia develops. Recommendations vary, one option: start with 10 minutes once a day, gradually increase frequency and duration.

May be performed transarterial or transvenous. Before the availability of liquid embolic agents (Onyx and NBCA), treatment was directed at the venous drainage (unlike pial AVMs) which had higher success, because the coils could be deployed to sacrifice the venous drainage very close to the point of arteriovenous shunting, resulting in thrombosis of the fistula. It is more difficult to deploy coils across the point of arteriovenous shunting from the arterial side, whereas the liquid embolic agents, particularly Onyx, can be injected at somewhat of a distance and pushed forward across the fistulous point. Whether a transarterial, transvenous, or combined approach is utilized depends on the unique angioarchitecture of the fistula.

Intracranial dural arteriovenous fistula surgery.

Cortical venous drainage is the defining angiographic feature that distinguishes benign (low-grade) from aggressive (high-grade) fistulas. (Borden I, Cognard I, and Cognard IIa are low-grade, all others are high-grade.)

Spontaneous closure of a dural arteriovenous fistula (dAVF) is a rare condition and only a few cases have been reported since its first description in 1976.

Only one report to document gradual closure of a dAVF by serial angiographic studies. The mechanism of spontaneous closure of dAVFs has not been fully elucidated ³⁾.

The various treatment options include transarterial and transvenous embolization, stereotactic radiosurgery, and open surgery. Although many of the advances in dural arteriovenous fistula treatment have occurred in the endovascular arena, open microsurgical advances in the past decade have primarily been in the tools available to the surgeon. Improvements in microsurgical and skull base approaches have allowed surgeons to approach and obliterate fistulas with little or no retraction of the brain. Image-guided systems have also allowed better localization and more efficient approaches. A better understanding of the need to simply obliterate the venous drainage at the site of the fistula has eliminated the riskier resections of the past. Finally, the use of intraoperative angiography or indocyanine green videoangiography confirms the complete disconnection of fistula while the patient is still on the operating room table, preventing reoperation for residual fistulas ⁴⁾.

For most patients, endovascular treatment, transarterial or transvenous, was the first option. Surgery was performed for the anterior cranial fossa DAVFs and other complex lesions draining mostly transverse-sigmoid sinus and tentorium. In 7% of cases a combination of endovascular + surgical treatment was used ⁵⁾.

see Radiosurgery for dural arteriovenous fistula.