Intracranial dural arteriovenous fistulas (dAVF) supplied by the ethmoidal arteries present a challenging surgical problem if not amenable to endovascular treatment. These dAVFs historically require larger open approaches via pterional or bifrontal craniotomies. We present a series of two cases via novel endonasal and transorbital approaches sparing the need for craniotomy.
Patient 1: A 64-year-old male presented with an intraparenchymal hemorrhage of the right gyrus rectus and diffuse subarachnoid hemorrhage. A cerebral angiogram demonstrated an ethmoidal dAVF (Fig. 1) with frontal basal vein venous drainage (Fig. 2). The dAVF was unable to be embolized due to difficulty penetrating the main draining vein.
Patient 2: A 60-year-old female presented with a diffuse subarachnoid hemorrhage secondary to a basilar tip aneurysm which was treated endovascularly. An incidental ethmoidal dAVF was found with drainage through a small frontal vein to the superior sagittal sinus. Follow-up angiogram showed a basilar tip aneurysm neck remnant requiring pipeline flow diversion and dual antiplatelet therapy (DAPT). Given the risk of hemorrhage on DAPT, it was decided to treat the dAVF first. Small lateral feeders prevented embolization of the dAVF. An endoscopic endonasal and transorbital approach was planned.
A right superior eye lid incision was carried deep to the orbital rim periosteum and the periosteum was elevated (Fig. 3). Care was taken to avoid significant depression of the orbit. The anterior ethmoidal artery was identified with a zero degree endoscope, ligated with hemoclips, and subsequently cauterized. A pedicled nasoseptal flap was harvested endonasally. The natural ostium of the sphenoid was opened and to gain access to the anterior skull base the ethmoid and maxillary sinuses were opened widely. High speed drill was used to perform a transcribiform craniotomy. The dura was opened and reflected away revealing several dural-based, arterialized venous structures originating from the ethmoid arteries. These venous structures were coagulated and cut. One large draining vein along the falx and several smaller draining veins were also coagulated (Fig. 4). Closure was performed with a dura repair inlay, dural flap, and the previously harvested nasoseptal flap. A follow-up angiogram demonstrated complete obliteration of the dAVF.
Conclusion: dAVFs with arterial supply from the ethmoidal arteries present a challenging problem that can be successfully and safely treated through endonasal and transorbital approaches sparing the need for pterional or bifrontal craniotomy.
