Evaluation of Results and Radiologic Follow-up in Detachable Balloon Occlusion Thera py of the Internal CarotidArtery Aneurysms

PURPOSE: The author has studied the clinical results of CT and MR findings of proximal carotid artery occlusion using detachable balloons in the treatement of unclippable internal carotid (IC) aneurysms. MATERIALS AND METHODS: From 1987 to 1995, twenty-eight patients with IC aneurysms were treated by proximal arteryocclusion with detachable balloons. Of these patients, 4 had aneurysms arising from the supraclinoid portion ofthe IC artery, 23 had aneuryms arising from cavernous portion of the IC artery, and one had aneurysm arising fromcervical portion of the IC artery. Of the 28 patients, 7 patients without CT or MR examinations were excluded inthis study. The mean follow-up period was 18.6 months. The causes of aneurysm formation were spontaneous in 17cases and traumatic in 4 cases. RESULTS: Of 20 patients with aneurysms arising from supraclinoid and cavernousportion of the IC artery, 16 patients (80%) had cranial nerve symptoms by mass effect. Five patients had epistaxis(3 patient), carotid cavernous fistula (1 patient) or subarachnoid hemorrhage (1 patient) due to aneurysmrupture. Two patients, each with aneuryms arising from supraclinoid and cervical portion of carotid artery had 9thand 12th cranial nerve symptom. There were three instances of complication after permanent occlusion; two patientshad subarachnoid and intracerebral hemorrhage by aneurysm rupture and expired. One patient had ischemia ofposterior cerebral artery teritorry after one day. Delayed ischemic event did not occur during the follow-upperiod. All aneurysms of the carotid artery below the level of ophthalmic artery presented radiographic proof ofcomplete thrombosis within two months. However, complete thrombosis of aneurysm was considerably delayed in twoaneurysms arising from the supraclinoid portion of the carotid artery. In long-term follow-up study, complete-lythrombosed aneurysms decreased in size slowly. But incompletely thrombosed aneurysms did not decrease in size fora long time and began to contract after formation of complete thrombosis. All three traumatic pseudoaneurymscharacteristically decreased in size rapidly, comparing with spontaneous aneurysms. CONCLUSION: In conclusion,proximal IC balloon occlusion for unclippable IC aneurysms is a convenient, safe, and effective way of producinganeurysm obliteration. Longer-term follow-up study is needed for incompletely thrombosed aneuryms after balloonocclusion of the proximal IC artery.

Production of Carotid Artery Aneurysm in Pigs

PURPOSE: To establish the method of constructing an experimental aneurysm model in porcine carotid artery. MATERIALS AND METHODS: Fourteen aneurysms were created in the carotid arteries of eight pigs. After paramedian incision under intravenous anesthesia, the common carotid artery and external jugular vein were separated. A portion of the latter was cut to make an aneurysmal sac and this was sutured to the side wall of the common carotid arterial wall (end to side). Within one week, an arteriogram was obtained in all pigs and color Doppler study was performed in four. Digital subtraction arteriograms were serially obtained three images/sec, and these were analyzed to determine the size of the sac and the neck, flow pattern in the aneurysm, and stenosis in the common carotid artery. RESULTS: Arteriographic findings were obtained in ten of 14 aneurysms. Six aneurysms were saccular in shape, and the mean size of the sac and neck was 16x10 mm and 5.3 mm, respectively. Four aneurysms were lobulated, and in these cases, the mean size of the sac and neck was 9x3 mm and 3.7 mm, respectively. The mean size of the proximal common carotid artery was 4.5 mm, and at the operation site, mean stenosis was 40%. CONCLUSION: In 10/14 cases (71%), we successfully established an aneurysm model in the porcine carotid artery, and believe that it is suitable for use in interventional neuroradiology experiments.

Experimental Model for Creation of Carotid Artery Aneurysms in Dogs

PURPOSE: To describe the detailed technique for producing experimental carotid aneurysms in dogs and the success rate, cause of failure and remedy, based on our experience. MATERIALS AND METHODS: Fourteen male dogs weighing 12-15kg were anesthetized with inhalation of 1-2% halothane and 50% nitrous oxide. Each surgical procedure was performed under sterile condition with the aid of an operating microscope. A paramidline incision 7-8 cm in length was made parallel to and medial to the external jugular vein in the dog's neck. The externaljugular vein was harvested as a 1cm vein pouch by ligation and division of the proximal and distal ends. The ipsilateral common carotid artery was exposed and clamped at both ends by a vascular clamp. A 5-mm long elliptical arteriotomy was made at the mid portion of the artery, and then end to side anastomosis between the artery andvein sac was performed by using interrupted 7-0 monofilament prolene sutures. Carotid arteriography or Doppler sonography was performed 1-6 weeks after aneurysm construction. RESULTS: Twenty experimental aneurysms we reconstructed, and 17 aneurysms were patent on follow up study, but one dog with two aneurysms died from hemorrhagicpneumonia 17 days after surgery. The overall patency rate was 75%. CONCLUSION: We demonstrated the feasibility of creating experimental aneurysm models in the dog and expect that the technique presented will help to avoidfailure in the construction of aneurysms.