Direct clipping of a blister-like aneurysm in the supraclinoid segment of the internal carotid artery: a clinical analysis of nine cases.

To investigate the method and outcome from direct clipping of a blister-like aneurysm (BBA) of the internal carotid artery supraclinoid segment. This study featured nine BBA patients, including eight females and one male. The patients presented subarachnoid hemorrhage (SAH) as the initial symptom and were diagnosed with BBA in the supraclinoid segment through a vascular exam and imaging. During the exam, the internal carotid artery was pressed to block the blood flow, and a transcranial Doppler (TCD) was performed to examine the blood flow in the (BBA) ipsilateral middle cerebral artery. The results showed that the blood flow was reduced by less than 40% in all nine patients. During surgery, a pterional craniotomy was used to fully expose the aneurysm for clipping. While clipping the aneurysm, the arterial wall at the root of the aneurysm was also clipped to improve stability. Intraoperative ultrasonography was performed before and after clipping to examine the blood flow in the parent artery, middle cerebral artery and anterior cerebral artery. Moreover, a TCD was performed within one week after surgery to monitor intracranial blood flow. During BBA clipping, four patients exhibited stenosis of the parent artery, but intraoperative ultrasonography showed adequate blood flow in the anterior cerebral artery and middle cerebral artery. TCD was performed within one week after surgery to examine the blood flow in the middle cerebral artery on the operative side; the TCD showed adequate blood flow. The patients recovered well after surgery and were discharged. Digital subtraction angiography (DSA) or computed tomography angiography (CTA) was performed six to 12 months after the surgery and showed no aneurysm relapse. Moreover, six patients exhibited no stenosis of the parent artery, 20% stenosis was observed in one patient, 30% stenosis was observed in one patient, and 50% stenosis was observed in one patient; none of the patients showed clinical symptoms, and all patients exhibited good collateral circulation. Therefore, if a pre-operative TCD shows adequate compensatory contralateral blood flow in the (BBA) ipsilateral middle cerebral artery after the internal carotid artery is pressed to block the blood flow, then direct clipping of the BBA is a simple and feasible treatment strategy. However, when the aneurysm is clipped, the artery wall at the root of the aneurysm must also be clipped to improve stability. With adequate compensation, partial stenosis of the parent artery is acceptable.