GDC Embolization of Basilar Bifurcation Aneuryms; Consideration of Posterior Cerebral Artery Occlusion

OBJECTIVE: To access the risk factors of posterior cerebral artery(PCA) occlusion during endovascular treat-ment of basilar bifurcation aneurysm and importance of collateral circulation through posterior communicating artery(PCoA) after PCA occlusion, the authors review the results of 25 patients with basilar bifurcation aneurysms treated with Guglielmi detachable coils(GDCs). METHODS: Male to female ratio was 1: 3.2(6: 19) and the mean age of this group was 54. Nineteen patients were presented with subarachnoid hemorrhage, 1 patient had neurologic deficits of hemiplegia and dysarthria, and 5 patients had incidental aneurysms with headache and dizziness. All patients underwent GDC embolization and their clinical results were analyzed. RESULTS: Seven of nine patients who resulted in PCA occlusion had a collateral flow from the anterior circulation through PCoA. Six patients had a PCoA larger than 1mm and they had no symptoms of ischemia after PCA occlusion. One patient who had a PCoA with 0.53mm in diameter had transient ischemic symptoms. The PCA arouse from the aneurysm neck in seven patients, and six of them resulted in PCA occlusion. Four of five patients who had aneurysms with broad neck(<4mm) resulted in PCA occlusion. CONCLUSION: The aneurysm with either broad neck or PCA arising from the aneurysm neck have a high risk of PCA occlusion. After PCA occlusion, significant blood flow from anterior circulation through the PCoA larger than 1mm in diameter can minimize the ischemic result in PCA territories.

Frontosupraorbital Approach and Orbitozygomatic Temporopolar Approach for High Basilar Aneurysms

Surgery of aneurysms around the basilar bifurcation artery is still one of the most difficult and challenging operations in the field of neurosurgery, because of their rare occurrences, unfamiliar anatomy and deeply located lesions. Two major surgical approaches, pterional approach and subtemporal approach, are conventionally used for upper basilar artery aneurysm. Neither approach, however, ensures easy treatment of high basilar bifurcation aneurysm, because there is always the chance of excessive retraction of the brain, nerves and vessels. In order to gain sufficient exposure of highly placed basilar bifurcation aneurysms, the surgical approach needs to be in the direction in which the surgeon can see the interpeduncular fossa from below. In an attempt to gain better exposure of these lesions, neurosurgeons have used a variety of surgical approaches. We have used forntosupraorbital(FSO) approach and orbitozygomatic temporopolar(OZTP) approach for seven cases of high basilar aneurysm including basilar bifurcation artery-SCA aneurysm. The advantage of these approaches are multidirectional view, wide operative field, less brain retraction and easy application of temporary clip. Therefore, authors would like to recommended these approaches in case of for high basilar aneurysm as a effective method of aneurysmal neck clipping.

Surgical Treatment of Posterior Circulation Aneurysms

Aneurysms arising from the posterior circulation are 5-19% of total intracranial aneurysms. Althought many neurosurgeons have challended with various innovations but the confinned surgical space, complicated anatomical structure and many small perforators to vital organ of brain were remained the barrier that we we have to overcome. From July 1987 to December 1994, we have been operated on 23 cases of posterior circuation aneurysms among 409 cases of surgically treated all intracranial aneurysms. The present 5.6% of all intracranial aneurysms, the average age of these patients was 49 years old. The ratio of male to female was 1 : 1.8. The number of basilar bifurcation artery aneurysms(BBAA) were 14(61%), the posterior cerebral artery(PCA) aneurysms 3(13%), the upper basilar trunk aneurysm 1, posterior inferior cerebellar artery(PICA) aneurysm 3(13%), anterior inferior cerebellar artery(AICA) aneurysm 1 and vertebral artery aneurysm 1. Five patients had accompanined with anterior circulation aneurysm and one patient had concomitant arteriovenous malformation. We have successfully clipped 12 cases and wrapped 2 cases of BBAA aneurysms through modified pterional approach and subtemporal approach according to the hight of basilar bifurcation and the other posterior circulation aneurysms are all clipped through most available approaches including lateral, far-lateral suboccipital and interhemispheric approach. Surgical outcome was good in 15 cases, fair in 4 cases, poor in 3 cases and one patient expired.

Subtemporal Approach vs. Pterional Approach in Basilar Bifurcation Aneurysms: 2 Case Reports

Two patients with basilar bifurcation aneurysm were treated by different approach, low lying posteriorly projecting aneurysm was clipped with subtemporal approach and high bifurcated basilar bifurcation aneurysm with multiplicity approached through pterional method. The author reviewed literature concerning the approaches of basilar bifurcation aneurysm.

Basilar Bifurcation Aneurysm Associated with Carotid-Ophthalmic Aneurysm: A Case Report

The report of basilar bifurcation aneurysm accompanying carotid-ophthalmic aneurysm is extremely rare and some technical dexterity must be needed on surgical treatment for each of two aneurysms. Authors report a case of basilar top aneurysm accompanied with a carotid- ophthalmic aneurysm clipped successfully in one stage operation with review of literatures concerning basilar bifurcation aneurysm, carotid-ophthalmic aneurysm and multiple aneurysms.

Surgical Approach to the Basilar Artery Aneurysms: Pterional Approach Via Optic-Carotid Triangle

There have been known two routes in pterional approach to the distal basilar artery aneurysms : one is via the space between the optic nerve and internal carotid artery(optic-carotid triangle: OCT) and the other is lateral to the ICA(retrocarotid approach : RCA). Although the approach via OCT has several advantages of its own, it had been considered to be used in a very limitted cases. Since we successfully clipped the aneurysms via OCT in 4 cases out of 12(33%), neuroradiological findings observed in these 4 cases are analyzed and reported. Measurement were made in the following items on the cartoid angiogram of the cases operated via OCT(OCT group) and RCA(RCA group) : the distance of ICA bifurcation from midline(D), height of ICA bifurcation from the base line between anterior and posterior clinoid process(H). Although these two values seemed to be higher in OCT group than those in RCA group, no significant difference was found. The product of D and H(D x H) was observed to be significantly higher in OCT group than in RCA group. The value of DxH is considered one of the indicaters of the size of OCT and is proved to be useful to judge whether approach via OCT is applicable or not. The approach via OCT has several such advantages as no injury to the occulomotor nerve, less retraction to ICA and easy visualization of p1 segment of the opposite side. The space of OCT can be used not only for clipping itself but also as a line of sight to the deep structures as well as clip applied from other routes.