Update Onyx embolization for plexiform arteriovenous malformation: Ante-grade drifting technique

Proof-of-Principle for AVM Embolization Complications Caused by the Proximal Occlusion Technique Using Onyx: A Theoretical Basis for Ante-Grade Drifting Technique

To analyze the complications of the standard proximal plug technique in arteriovenous malformations (AVMs) embolization by Onyx and promote ante-grade drifting technique for AVM embolization. Seven publications reporting complications of AVM embolization by Onyx were identified and reviewed. Render descriptive statistics regarding causes of ischemic and hemorrhagic complications within 1 month following treatment were provided. A novel Onyx injection technique was proposed to overcome these problems. All reported transarterial Onyx AVM embolizations were conducted by employing the proximal plug technique. Causes of complications elicited by utilizing this strategy may generally be attributed to long-fluoroscopy and long-procedure times, embolisate reflux across a considerable extent of the vessel, catheter entrapment, extravasation of Onyx from the arterial lumen, catheter transgression through the arterial wall, the use of an Onyx volume exceeding, and venous occlusion preceding arterial feeder shutdown. Complications occurring during the course of attempts at embolizing AVMs utilizing Onyx constitute unfortunate causes of patient morbidity resulting from this conventional technique. We suggest that institution of a novel "ante-grade drifting technique" for Onyx injection may avoid these commonly elicited deficits. The proximal plug technique has a series of drawbacks that lead to serious adverse outcomes of AVM embolization. The Onyx embolization technology for AVM could be updated to improve clinical outcomes.

Acquired pial arteriovenous fistula secondary to cerebral cortical vein thrombosis: A case report and review of the literature

Pial arteriovenous fistulas (AVFs) are rare neurovascular malformations. They differ from arteriovenous malformations (AVMs) in that they involve single or multiple feeding arteries, draining directly into a dilated cortical vein with no intervening nidus. Pial and dural AVFs differ in blood supply, as the first originate from pial or cortical arteries and the latter from outside the dural leaflets. Unlike dural AVFs, most of the pial AVFs are supratentorial. The vast majority are congenital, manifesting during infancy. Acquired pial AVFs are significantly rarer and occur after vasculopathy, head trauma, brain surgery, or cerebral vein thrombosis. We describe a unique case of an acquired pial AVF in a 50-year-old man secondary to a cortical vein thrombosis manifesting as a focal-onset seizure with secondary generalization. A cerebral digital subtraction angiography revealed a low-flow pial AVF fed by a postcentral branch of the left middle cerebral artery draining to the superior sagittal sinus via a cortical vein. It also showed a collateral venous circulation adjacent to the previously thrombosed left parietal vein. There was no evidence of an associated dural AVF or venous varix. Endovascular treatment was scheduled three months later, but the angiogram preceding the embolization showed spontaneous and complete closure of the malformation. To our knowledge, this is the first case illustrating acquired pure pial AVF unaccompanied by a dural component following cortical vein thrombosis, eventually resulting in an unprompted closure.

Sylvian fissure arteriovenous malformations: case series and systematic review of the literature

BACKGROUND

Sylvian fissure arteriovenous malformations are rare but important vascular lesions, whose importance lies in both haemorrhage and seizure risk. Although surgery has been recommended as a treatment, the overall estimation of success has not been reported to render outcomes easier to understand in comparison to other treatment modalities.

OBJECTIVES

This systematic review of the literature and two cases aims to illustrate the results of surgery as a contemporary treatment option and present a novel anatomical classification system for Sylvian fissure arteriovenous malformations.

MATERIALS AND METHODS

A systematic review was performed by searching MEDLINE (PubMed), EMBASE and Cochrane electronic bibliographic databases from conception to 2018. The following keywords were used: 'Sylvian fissure' AND 'AVM' OR 'arteriovenous malformation' OR 'intracranial arteriovenous malformation' OR 'cerebral arteriovenous malformation' OR 'brain arteriovenous malformation'. The search strategy was not limited by study design but only included keywords in the English language. In addition, two local institution Sylvian fissure arteriovenous malformations are presented and incorporated.

RESULTS

A total of nine full-text articles were included in the analysis. The results of reported cases and the literature review emphasise the role of surgery in the treatment of Sylvian fissure arteriovenous malformations, with an acceptable result in carefully selected patients. We propose a classification system which may inform the choice of surgical approach for these lesions.

CONCLUSIONS

Surgery remains the cornerstone of Sylvian fissure arteriovenous malformation treatment, which may apply to high-grade lesions in this special anatomical location.