Microsurgical Clipping of an Unruptured Basilar Tip Aneurysm with a Posterior Thalamoperforating Artery Mimicking Dome Origin on Preoperative Angiography.

Basilar tip (BT) aneurysms are challenging due to their deep location and proximity to posterior thalamoperforating arteries (PThPAs) and the oculomotor nerve.1-5 Posterior circulation aneurysms have a higher rupture risk than those in the anterior circulation.6 Surgical complexity depends on aneurysm size, projection, and relationship to the PThPAs, which may not be fully delineated by angiography, despite its gold standard role. Given the severe consequences of perforator occlusion, microsurgical treatment remains an important option in selected patients, offering direct anatomical clarification when perforator involvement is suspected.7-10 We present a BT aneurysm with the angiographic impression that a PThPA arose from the aneurysm dome.