Ruptured Basilar Tip Aneurysm in a Patient with Bilateral Internal Carotid Artery Occlusion Successfully Treated with Bilateral Superficial Temporal Artery–Middle Cerebral Artery Anastomoses: Case Report

Some ruptured intracranial aneurysms concomitant with major artery occlusion may not be amenable for standard clipping or coiling due to the specific hemodynamic conditions. The long-term effect of flow reduction therapy for such aneurysms is largely unknown.A 45-year-old woman presented with subarachnoid hemorrhage due to a ruptured basilar tip aneurysm. Angiography revealed that the bilateral internal carotid arteries were hypoplastic and that the anterior circulation was fed by the collateral flow through the bilateral posterior communicating arteries and the posterior choroidal arteries. Endovascular treatment failed because it was extremely difficult to secure the catheter at the neck of the aneurysm and insert the coil safely because it was a small aneurysm with a wide neck. In addition, direct clipping was risky due to the location and projection of the aneurysm. We therefore adopted the 2-stage bilateral superficial temporal artery-middle cerebral artery bypass to alleviate the vascular demand on the anterior circulation, with the aim of reducing the hemodynamic stress to the basilar bifurcation. The patient had no rebleeding for 4 years after surgery, with gradual shrinkage of the aneurysm.All the possible treatment options should be carefully assessed because the long-term effect of the flow alternation method to prevent rebleeding has not been proved. However, our case suggests that the strategy of reducing the hemodynamic stress at the parent artery may be effective even in selected cases of ruptured aneurysms for which standard clipping or coiling is not feasible.