OBJECTIVETo study the clinical characteristics, surgical principles and treatment options of blood-blister-like cerebral aneurysms in supra-clinoid segment of internal carotid artery.

METHODSTwelve blood-blister-like aneurysms were retrospectively studied including 4 open-surgery cases and 8 endovascular-treated cases from November 2008 to December 2012. Patients comprised 8 female and 4 male patients, whose mean age was 46.6 (range 38-56) years. Eleven patients presented with severe headache as the primary symptom, and 1 patient was found with aneurysm incidentally. Preoperative Hunt-Hess graded 0 in 1 patient, graded I in 5 patients, graded II in 4 patients, and graded III in 2 patients. By DSA examinations, 4 blood-blister-like aneurysms located in anterior wall and 8 in medial-anterior wall of supra-clinoid segment of internal carotid artery. Open surgical treatment included direct clipping, trapping, or wrapping and interventional treatment included stent-assisted coiling or simple stent placement. Intra-operative electroencephalogram and somatosensory evoked potentials monitoring was regularly used. Microvascular Doppler ultrasonography and indocyanine green videoangiography were used to assess blood flow in parent and branch vessels. The patients were followed up at 6 months by CT angiography (CTA) examination in outpatient clinic.

RESULTSFor 4 open surgeries, 2 aneurysms were directly clipped, 1 was trapped and 1 was wrapped. The patient underwent trapping paralyzed postoperatively. For endovascular treatment, 6 patients were coiled assisted with stents and 2 patients were treated with simple stent placement. All the patients were followed with a mean follow-up time of 16 months (range, 6-61 months). At 6 months follow-up, 3 out of 4 surgical treated patients had good outcome and 1 was moderately severe disabled by modified Rankin scale; 1 patient underwent wrapping recurred and was transferred to endovascular treatment. Of the 6 patients treated with stent-assisted coiling, 4 patients were recurrent and coil replacements were performed. Two patients with simple stent placement had no recurrences.

CONCLUSIONSBlood-blister-like aneurysm is a special type of complex cerebral aneurysm. Comprehensive understanding of blood-blister-like aneurysm is the key to successful treatment.Open surgery is difficult procedure with high risk and complications while stent-assisted coiling has a high recurrent rate. To date, neither is the safe and effective treatment option.