Transvenous embolization of the direct carotid-cavernous fistula via the pterygoid plexus: illustrative case

BACKGROUND Endovascular treatment is the mainstay of treatment for carotid-cavernous fistulas, but endovascular approaches vary widely. The authors report a rare case of a direct carotid-cavernous fistula with cranial nerve symptoms caused by rupture of a giant aneurysm in which selective transvenous embolization via the pterygoid plexus was performed. OBSERVATIONS An 81-year-old man presented with headache and various progressive cranial nerve symptoms due to a direct carotid-cavernous fistula caused by a ruptured giant aneurysm. All the draining veins visualized on preoperative examination immediately before the treatment were occluded except for the pterygoid plexus. Therefore, the authors chose the dilated pterygoid plexus to approach the shunted pouch at the cavernous sinus and achieve shunt obliteration by selective embolization with coils and n-butyl cyanoacrylate. LESSONS Careful study of the three-dimensional rotational images in the preoperative examination is important when considering the various approaches to surgery. The pterygoid plexus can be an effective venous approach route to reach the cavernous sinus area.