Case report of a 60 years old male patient with recent diagnosis of an occipital dural arteriovenous fistula classified CognardTyp IV, treated by transfemoral cerebral angiography and embolization with liquid embolization material (Onyx).

Dural arteriovenous fistula (DAVF) is a type of AVM in which there is a communication between dural arteries and cerebral venous sinuses. These lesions constitute 10–15% of all cerebral AVMs and most of them seemed to be acquired, only some are congenital. There is a female to male ratio of 2:1 and most of them are diagnosed in the fifth and sixth decade. The distinguishing feature between DAVF and cerebral AVM is the fact that there is no parenchymal nidus and there is a dural arterial supply [1].

We demonstrate a case of a 60-year-old man with recent diagnosis of an occipital dural arteriovenous fistula classified Cognard Typ IV, treated by transfemoral cerebral angiography and embolization with liquid embolization material (Onyx - composed of a mixture of ethylene–vinyl alcohol copolymer suspended in the solvent dimethyl sulfoxide (DMSO) – Tantalum is added for radiopacity).

We present a case of a 60-year old male patient with recent diagnosis of an occipital dural arteriovenous fistula classified Cognard Typ IV, treated by transfemoral cerebral angiography and embolization with liquid embolization material (Onyx).

The therapeutic angiography was performed in intubation anesthesia, our interventional neuro radiologist took the common femoral artery as an arterial access supported by a 6-F-vascular lock, a 6-F-guiding catheter was positioned in the left maxillary artery (Figure 1), furthermore a distal access catheter was placed at the branchpoint of the middle meningeal artery(Figure 2). Using this guiding catheter a microcatheter was positioned at the origin of the fistula.

                                                                             Figure 1: showing the catheter in the left maxillary artery a) ap position; b) side view

                                             Figure 2: a/b showing the distal accesssecond catheter (ACCESS®) at the branch point of the middle meniongeal artery

Figure 3: a positioning of the microcatheter in front of the arterial feeders; b digital subtraction angiography showing the veins onyx cast with complete obliteration of the fistula.

                                     Figure 4: a/b (a ap-view;b side view) digital subtraction angiography of the left common carotid artery showing noresidual fistula.

Our used technique of trans arterial embolization is ideally used for high- grade DAVFs, such as those with direct cortical venous drainage, or in situations in which venous access is limited. There is a list of the advantages of the trans arterial embolization technique:

(1) there is the possibility to occlude the arteriovenous fistula transition through a trans arterial approach, decreasing the possibility of flow diversion into an alternate venous pathway.

(2) using this technique there is no limitation by venous access(e.g., stenotic or thrombosed venous sinuses).

(3) after the arterial pathway there is no higher risk of venous complications.

(4) trans venous embolization can be followed by secondary site as de novo DAVFs resulting of venous hypertension.

(5) by this technique specific complications to trans venous routes can be avoided (e.g., abducens nerve palsy from catheterization of the superior petrosal sinus) [1].

Using as super selective microcatheter angiography, three-dimensional, rotational angiography and a form of high-resolution flat-panel computed tomography (CT) known as “DynaCT” are recommended in defining the arterial and venous anatomy of a DAVF both before and after embolization. To prevent premature polymerization and contamination of diagnostic catheters and solutions, embolic agents such as Onyx should be handled on a separate able when not in use, furthermore a separate set of gloves should be used prior to handling these agents and at the end of the procedure prior to final diagnostic angiography [1].

Onyx is one possibility of liquid embolization, it is composed of a mixture of ethylene–vinyl alcohol copolymer suspended in the solvent dimethyl sulfoxide (DMSO) – Tantalum is added for radiopacity- and first reports were published in the 1990, this drug is available in Europe since 1999.

Trans arterial embolization technique is recommend in dural arteriovenous fistulas Cognard Typ IIb – V.

Classification of dural arteriovenous fistulas (Cognard):

[2] There are some technical advantages by using ONYX:

1. less operator dependence from the interventional radiologist.
2. No wedged microcatheter position is required.
3. Different feeder scan be occluded with a single injection from a single pedicle.

For planning the intervention the following points should be considered.

1. Where is the location of the point/points of the fistula?
2. Location of the feeding arteries?
3. How is the venous drainage pattern?
4. Where are the most promising pedicles to be injected?

After the embolization procedure an immediate cerebral CT scan is recommend, furthermore you should care about pain medication caused by the dural involvement and low-molecular weight heparin should be prescribed for 1 to 4 weeks to avoid venous thrombosis [1].

Disclosure

All co-authors do not report conflicts of interest.