The Operation for Dural Arteriovenous Fistulas in Children
Based on DAVF location: Patient positioning depends on the DAVF’s location. For anterior fossa DAVFs, the supine position is routinely used. In cases of posterior circulation malformations, a prone, park bench or sitting position might be used.
Head: The head should be secured with a head holder.
Location of DAVF: Depending on location of the malformation different approaches can be used. Note that scalp and bony work could entail moderate to severe blood loss.
Preoperative endovascular obliteration: The current first-line treatment for cranial DAVFs is endovascular. Neurointerventional arterial obliteration might also be performed before open surgical approaches to decrease the flow through the fistula and to simplify the angioarchitecture of complex lesions prior to surgery. Nevertheless, arterial ligation alone cannot be considered curative. To achieve cure, the embolizing material must penetrate to the venous side of the malformation.
Surgical occlusion of all arterial feeders to the fistula: This can be curative if all the feeders can be obliterated as they enter the fistula, as in the case of some tentorial AVFs.
Interruption of the fistula via open dural or cortical vein ligation: This technique is especially suited for those fistulae where leptomeningeal venous reflux cannot be reached or it is considered dangerous (i.e. anterior fossa dural fistulae supplied by ophthalmic artery branches) through a neurointerventional approach. Disconnection of the arterialized vein (“red dilated veins”) should be performed as close as possible to the dural fistula using bipolar and microsurgery aneurysm clips (11,16,29). Hemoclips can be used with the disadvantage that they cannot be removed or repositioned. Caution must be paid to preserve veins and uninvolved segments of the sinuses that might contribute to anterograde normal flow of brain parenchyma. See video.
Skeletonization with or without sinus packing: The sinus can be skeletonized using high speed drill. If packing is necessary, it is usually achieved with a combination of muscle, cotton, Gelfoam, Floseal and Surgicel.
Skeletonization and excision of the sinus: This is a more radical and definitive approach. It generally entails skull-base surgery techniques(8,15). However, this technique might be too aggressive in children due to the excessive blood loss associated with excision of the sinus and also because open draining vein interruption is generally successful.
Confirm obliteration: Indocyanine green (ICG) video-angiography has recently been used as an intraoperative adjunct for DAVFs surgery for localization and confirmation of complete obliteration. An intraoperative angiogram might be also used with the advantage that several vessels can be injected, thus ruling out the presence of alternative feeders.
“Access surgery”: In cases where arterial or venous access for endovascular treatment proves to be very challenging, direct exposure of the carotid(4) or venous sinuses can be performed to facilitate endovascular techniques.
Substitutes: If large bony or dural defects are present, dural substitutes and bone substitutes with or without meshes can be used.
Watertight: Posterior fossa dural closure should be watertight.
Scalp: Routine closure techniques can be applied to the scalp.