Treatment of Intracranial Aneurysms by Balloon Embolization

The efficacy of endosaccular aneurysm occlusion in alleviating neurological deficits produced by mass effect

Endovascular obliteration of intracranial aneurysms with preservation of the parent artery (endosaccular occlusion) has been advocated for patients who fail or are excluded from surgical clipping and cannot undergo Hunterian ligation therapy. To clarify the effect that endosaccular occlusion has on the presenting neurological signs, 26 patients with aneurysms and symptoms related to mass effect who underwent this therapy were followed for a mean of 60 months. Only patients with objective neurological deficits who had not suffered a hemorrhage were included in this series. Response to therapy was classified into one of three groups: "resolved," if the patient had complete resolution of presenting signs; "improved," if significant and sustained improvement was recorded in the neurological examinations, and "unchanged," if no change was observed. Thirteen patients (50%) were classified as resolved, 11 (42.3%) as improved, and two (7.7%) as unchanged. A comparison of patients classified as resolved with those who were improved revealed that the former group had less wall calcification (30% vs. 60%) and a shorter duration of symptoms. Patients with neurological sign resolution (62%) were more likely to have totally occluded aneurysms on late follow-up arteriograms than those who had improvement (28%) or were unchanged (0%). This study suggests that endosaccular embolization therapy can improve or alleviate presenting neurological signs unrelated to hemorrhage or distal embolization in the majority of cases.

Aneurysm recurrence following endovascular balloon occlusion

Endovascular balloon occlusion is an alternative treatment for surgically unclippable cerebral aneurysms. The results of aneurysm occlusion with either a silicone or a latex balloon in a common carotid artery bifurcation aneurysm model are compared to determine which type of balloon was least likely to result in aneurysm recurrence. Five rabbits each underwent endovascular balloon occlusion with either a silicone or a latex balloon, with seven rabbits serving as controls. At 3 months postocclusion, nine of the 10 balloon-treated aneurysms had recurred. The recurrent aneurysm tended to be larger in animals treated with silicone than with latex balloons. A dense fibrotic response was present around the collar of the latex balloons, but no significant fibrotic response was found in the silicone balloon group. This study suggests that with currently available balloons, the initial complete angiographic obliteration of an aneurysm following balloon occlusion should not be interpreted as a cure and that periodic follow-up angiography should be performed.

Selection and combination of various endovascular techniques in the treatment of giant aneurysms

Between April, 1989, and January, 1991, a total of 19 cases of giant aneurysm were treated by the endovascular approach. The patients included seven males and 12 females aged 15 to 72 years. Detachable balloons, occlusion coils, and ethylene vinyl alcohol copolymer liquid were used as embolic materials. In seven cases, thrombosis of the aneurysmal sac and/or base was achieved while sparing the parent arterial flow, complete obliteration of the aneurysm was achieved in four of these. Of these four patients, the thrombotic material was a detachable balloon in two, a combination of a detachable balloon and coils in one, and occlusion liquid in one. In the other three cases, complete occlusion was not achieved; one aneurysm was occluded with a detachable balloon and two with coils. In 11 patients, the parent artery was occluded either by trapping or by proximal arterial occlusion, and all patients showed complete occlusion of the aneurysms. In one patient, a combined bypass procedure and parent artery occlusion was performed. Among the 19 cases in this series there were four transient ischemic attacks, one reversible ischemic neurological deficit, and one death due to aneurysmal rupture during the procedure. Two patients died in the follow-up period, one from pneumonia 2 months postoperatively and the other from acute cardiac failure 2 weeks following surgery. Both deaths were unrelated to the endovascular procedure. It is concluded that the endovascular treatment of giant aneurysms remains difficult because of the large and irregular shape of the aneurysmal base and thrombus in the aneurysmal sac. The proper selection and combination of the available endovascular techniques is therefore of critical importance.

Endovascular occlusion of vertebral arteries in the treatment of unclippable vertebrobasilar aneurysms

Twenty-one patients with aneurysms of the vertebrobasilar circulation underwent unilateral or bilateral endovascular occlusion of the vertebral artery. Six patients presented with subarachnoid hemorrhage (SAH), 10 with mass effect, four with mass effect and SAH, and one with ischemic symptoms. Thirteen patients had good outcomes with complete clinical and angiographic cure. Six patients had partial thrombosis of their aneurysms. There was one death and one treatment failure. One patient suffered transient stroke. It is concluded that endovascular occlusion of the vertebral artery following test occlusion is a safe and effective treatment for proximal aneurysms of the vertebrobasilar circulation.

Interventional neurovascular treatment of a giant intracranial aneurysm using platinum microcoils

A 70-year-old woman presented with symptoms of progressive cerebellar dysfunction due to mass effect from a giant, expanding, posterior fossa aneurysm arising from the distal vertebral artery. The aneurysm contained thrombus and had a broad-based neck. From a transfemoral approach, with the patient under local anesthesia, a 2.2 French microcatheter was guided through the vertebral artery and placed directly into the aneurysm. Six 5 x 15-mm platinum microcoils were deposited into the residual lumen of the aneurysm, resulting in complete thrombosis with obliteration of the aneurysm and preservation of the parent artery. Endovascular coil embolization therapy by interventional neurovascular techniques may provide a therapeutic alternative in the management of surgically difficult symptomatic intracranial aneurysms.

Endovascular detachable balloon embolization therapy of cavernous carotid artery aneurysms: results in 87 cases

Interventional neurovascular techniques for treating patients with intracranial aneurysms are now being performed in selected cases. In certain anatomical locations that are difficult to reach surgically, such as the cavernous portion of the internal carotid artery (ICA), this technique may be especially useful. The procedure is performed from a transfemoral approach, using local anesthesia, thus permitting continuous neurological monitoring. Between 1981 and 1989, 87 patients diagnosed as having an intracavernous aneurysm were treated with endovascular detachable balloon embolization techniques. The patients ranged in age from 11 to 84 years. The presenting symptom was mass effect in 69 cases (79.3%), rupture of a preexisting aneurysm resulting in a carotid-cavernous sinus fistula in eight cases (9.2%), trauma resulting in a cavernous pseudoaneurysm in seven cases (8.0%), and hemorrhage in three cases (3.4%). Therapeutic occlusion of the ICA across or just proximal to the aneurysm neck was performed in 68 patients (78.2%). Since 1984, with the development of a permanent solidifying agent (2-hydroxyethyl methacrylate) to fill the balloon, it is now feasible in some cases to guide the balloon directly into the aneurysm and preserve the parent artery; this was achieved in 19 cases (22%). Follow-up examination has demonstrated complete thrombosis with partial or total alleviation of symptoms in all patients with therapeutic occlusion of the parent vessel. Of the 19 patients with preservation of the parent artery, follow-up studies have demonstrated total exclusion in 12 cases (63%) and subtotal occlusion of greater than 85% in seven cases (37%), with clinical improvement in all cases. Complications from therapy included transient cerebral ischemia during or after therapy requiring volume expansion in seven cases, embolic symptoms requiring antiplatelet medication in two cases, and stroke in four cases; there were no deaths. Detachable balloon embolization therapy, particularly for large and giant symptomatic aneurysms of the cavernous ICA, can be an effective mode of treatment.

Detachable balloon embolization therapy of posterior circulation intracranial aneurysms

Treatment of complex and surgically difficult intracranial aneurysms of the posterior circulation is now being performed with intravascular detachable balloon embolization techniques. The procedure is carried out under local anesthesia from a transfemoral arterial approach, which allows continuous neurological monitoring. Under fluoroscopic guidance, the balloon is propelled by blood flow through the intracranial circulation and in most cases, can be guided directly into the aneurysm, thus preserving the parent vessel. If an aneurysm neck is not present, test occlusion of the parent vessel is performed and, if tolerated, the balloon is detached. Twenty-six aneurysms in 25 patients have been treated by this technique. The aneurysms have involved the distal vertebral artery (five cases), the mid-basilar artery (six cases), the basilar artery (11 cases), and the posterior cerebral artery (four cases). The aneurysms varied in size and included three small (less than 12 mm), 15 large (12 to 25 mm), and eight giant (greater than 25 mm). Fifteen patients (60%) presented with hemorrhage and 10 patients (40%) with mass effect. In 17 cases (65%) direct balloon embolization of the aneurysm was achieved with preservation of the parent artery. In nine cases (35%), because of aneurysm location and size, occlusion of the parent vessel was performed. Complications from therapy included three cases of transient cerebral ischemia which resolved, three cases of stroke, and five deaths due to immediate or delayed aneurysm rupture. The follow-up period has ranged from 2 months to 43 months (mean 22.5 months). In cases where posterior circulation aneurysms have been difficult to treat by conventional neurosurgical techniques, intravascular detachable balloon embolization may offer an alternative therapeutic option.