The Operation for Dural Arteriovenous Fistulas in Children

Patient Positioning

• Based on location of DAVF and surgical approach: 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. Secure the head with a head immobilization device.

Surgical Approach

• Based on location of DAVF: Depending on location of the DAVF, different approaches can be used. Note that scalp and bony work could entail moderate to severe blood loss due to transosseous arterial supply, as well as emissary veins.

Intervention

DAVF treatment options include

• Preoperative endovascular obliteration: The first-line treatment for cranial DAVFs is endovascular intervention. 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 pedicle ligation alone cannot be considered curative. To achieve cure, the embolisate must occlude the fistulous point. One surrogate metric is penetration of the embolisate 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 fistulas where leptomeningeal venous reflux cannot be reached or for which a neurointerventional approach is considered dangerous (eg, anterior fossa dural fistulas supplied by ophthalmic artery branches). Disconnect the arterialized vein (red, dilated veins) as close as possible to the dural fistula using bipolar and microsurgery aneurysm clips (4,35,36). 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.
• Skeletonization, with or without sinus packing: The sinus can be skeletonized using a 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 (37,38). 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.
• Obliteration confirmation: ICG video angiography has recently been used as an intraoperative adjunct for DAVFs surgery for localization and confirmation of complete obliteration (39). An intraoperative angiogram might be also used, with the advantage that several vessels can be injected, thus ruling out the presence of alternative feeders.

Closure

• Substitutes: If large bony or dural defects are present, dural substitutes and bone substitutes with or without meshes may be employed.
• Watertight: Posterior fossa dural closure should be watertight to prevent CSF leaks.
• Scalp: Routine closure techniques can be applied to the scalp.