Background: Parent artery occlusion (PAO) is an alternative surgical strategy for complex internal carotid artery (ICA) aneurysms, which are unclippable because of their anatomical structures, including a broad neck, fragile dome, critical branch, and cavernous sinus location. Despite revascularization, ischemic complications occur after the PAO because of several factors, such as hypoperfusion, embolism, and perforator impairment.
Methods: Acute ischemic complications and their mechanisms were analyzed in a consecutive series of 32 patients presenting with complex ICA aneurysms treated by PAO.
Results: Fourteen ruptured and 18 unruptured aneurysms were located in the cavernous sinus (n = 16) and paraclinoid portion (n = 16). Preoperative balloon test occlusion was performed to investigate ischemic tolerance and to select the bypass method in 24 cases. An extracranial-intracranial bypass was constructed using the superficial temporal artery in 17, and a saphenous vein graft was done in 12 cases. Although postoperative hypoperfusion was prevented by revascularization based on the balloon test occlusion, acute ischemic complications due to perforator occlusion and thromboembolism were observed in 10 cases after the surgery. Five cases presented with impairment of perforating branches adjacent to the occluded parent artery, resulting in prolonged neurologic deterioration.
Conclusion: The distal location of ICA aneurysms is a risk factor for the perforator impairment, when treated by PAO, and PAO by clip placement is preferred to endovascular coiling to prevent of perforator impairment.