We reviewed 12 cases of anterior wall aneurysms of internal carotid artery. We classified those aneurysms into two types as follows: 1) “chimame” (blister) type, which has a thin wall and fragile neck; and 2) “non-chimame” type, which has a usual wall and neck. Six cases had “chimame” type aneurysms. All 6 patients were women, ranging in age from 37 to 61 years (mean, 49 years). All aneurysms were the source of subarachnoid hemorrhage (SAH). The size of the aneurysms varied from 1 to 4mm with a mean of 2.8mm. There were also 6 cases with “non-chimame” type aneurysms. Three patients were men and 3 were women, ranging in age from 47 to 68 years (mean, 56 years). Two aneurysms were the source of SAH. The size of aneurysms varied from 5 to 18mm with a mean of 12mm. Intraoperative rupture occurred in 5 of the 6 “chimame” type aneurysms, and in only one of the 6 “non-chimame” type aneurysms. Neck clipping was done in one of the 6 “chimame” type aneurysms, but was done in all of the “non-chimame” type aneurysms. One patient of “chimame” type aneurysm treated by trapping died, but the others had good recovery.
“Chimame” type anterior wall aneurysm is easy to rupture, difficult to clip, and so necessitates special surgical techniques such as wrapping or trapping with bypass. On the other hand, “non-chimame” type anterior wall aneurysm can be clipped relatively safely. However, it is important not to induce intraoperative rupture during dissection and clipping, because the aneurysm is severely adherent to the frontal lobe or temporal lobe.

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We report 17 cases of aneurysms at the bifurcation of the internal carotid artery (ICA bif). There were 10 males and 7 females. The age ranged from 30 to 70 years old (average of 48.3 years). Multiple aneurysms were seen in 8 cases (47%). Thirteen patients presented with subarachnoid hemorrhage (SAH). Nine of these 13 patients suffered from SAH due to the rupture of ICA bif aneurysms. Direct surgery for neck clipping of the ICA bif aneurysms was carried out in 15 patients. In 13 patients, the clip was applied from the space superior to the ICA bifurcation between the anterior cerebral artery (ACA) and middle cerebral artery (MCA). In 2 cases of posteriorly projecting aneurysms, 1 was clipped from the space inferior to the ACA and medial to the ICA. The other aneurysm was clipped using a right-angled ring clip with the ACA being included in the ring. In 6 cases with unruptured ICA bif aneurysms, 5 had good results and 1 had a mild deficit due to the occlusion of perforating artery from the MCA. In 9 ruptured ICA bif aneurysms, 4 had good recovery, 2 had moderate disability, 1 was severely disabled, 1 was vegetative and 1 died. The causes of poor outcomes in these 5 cases were the severity of SAH in 3 cases and occlusion of the perforating artery from the MCA in 1 case and vasospasm in 1 case.
Clinical characteristics of the ICA bif aneurysm include younger age at presentation, male predominancy, and high rate of multiple aneurysms. In the majority of aneurysms, neck clipping can be accomplished from the space superior to the ICA bifurcation, but it should be modified for those projecting posteriorly. Preservation of the perforating arteries behind the dome is important to obtain good outcomes.

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We report 3 cases with a ruptured aneurysm on the fenestrated basilar artery in relation to surgical approach. There were 2 females and 1 male, who were 47, 53 and 57 years old, respectively. On admission, a CT scan showed thick subarachnoid hemorrhage in 2 cases and thin in 1, and each case was classified into Grade 1, Grade 2 and Grade 4 of Hunt and Kosnik. All cases had an aneurysm rising from the proximal portion of the ventral side of the fenestrated basilar artery on the angiogram, which ranged in size from 3 to 5mm. The aneurysm was clipped completely in the chronic stage through the presigmoid route using the combined supra- and infratentorial transpetrosal approach. In 2 patients, postoperative courses were uneventful apart from abducens palsy and incompletely diminished hearing on the operative side. In the remaining 1, anticoagulant therapy had been done carefully for 14 days with 1-week barbiturate coma because of brain swelling due possibly to sigmoid sinus occlusion. She was discharged with hearing impairment 2 months after the surgery.
In this study, we discuss the usefulness and limitation of presigmoid approach for aneurysms of the basilar artery trunk and emphasize the intensively careful management with barbiturate coma and/or anti-coagulant therapy after an unexpectedly invasive surgery.

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We performed the trapping-evacuation method in 2 cases of large carotid-ophthalmic aneurysm. In Case 1, the patient, a 41-year-old female, complained of headache. Magnetic resonance angiography (MRA) revealed a left internal carotid aneurysm, which proved to be a large carotid-ophthalmic aneurysm by left carotid angiogram. A left frontotemporal craniotomy was performed and the aneurysm was exposed by the pterional approach after the anterior clinoid process resection. During the operation, the double-lumen catheter was inserted for the temporary proximal occlusion of the internal carotid artery. Then the intracranial internal carotid artery distal to the aneurysm was occluded with a temporary clip. The aneurysm was collapsed by evacuation through the balloon catheter with a 20ml syringe. The aneurysm was clipped and intraoperative digital subtraction angiography (DSA) was carried out to confirm successful obliteration of the aneurysm.
In Case 2 the patient, a 43-year-old female, was suffered from a sudden headache and consciousness disturbance. CT scan on admission showed acute subdural hematoma and intracerebral hematoma of the right temporal lobe. Right carotid angiogram revealed a large ophthalmic-carotid aneurysm and middle cerebral artery aneurysms. Direct surgery was carried out for a ruptured middle cerebral artery aneurysm on Day 0. On Day 46 after admission the unruptured large ophthalmic-carotid aneurysm was treated by trapping-evacuation method as in Case 1.
In conclusion, the trapping-evacuation method using balloon catheter for the large or giant internal carotid aneurysms was useful for the treatment of direct clipping. Intraoperative DSA was valuable not only for the balloon technique but also for the confirmation of complete clipping of the aneurysm.

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We investigated the relation between cerebral blood flow (CBF) and surgical procedures in patients with surgically treated hypertensive putaminal hematomas. The subjects were 20 patients with hypertensive putaminal hematomas, consisting of 10 with stereotactic aspiration of hematomas and 10 with evacuation of hematomas. CBF was determined by means of stable xenon-enhanced computed tomography before and after surgery and in the chronic stage. The mean global CBF of the subjects was reduced in accordance with hematoma volume. CBF on the hematoma side was not markedly improved after evacuation for removal of hematoma to compared with that after aspiration for removal of hematoma. These results suggest that aspiration for removal of hematoma might be beneficial for patients with hypertensive putaminal hematomas from the aspect of CBF.

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We studied the clinical and pathological aspects of 4 arteriovenous malformations (AVM) that were removed totally after preoperative embolization using poly (HEMA-co-MMA) or EVAL. Histopathological examination of AVM nidus embolized with poly (HEMA-co-MMA) showed mild inflammatory cell infiltrations in the vessel wall and small hemorrhages within the nidus and its surrounding brain tissue. On the other hand, EVAL-embolized AVM nidus demonstrated embolic materials within the vessels and inflammatory reaction of the vessel wall and its surrounding tissue, and patchy hemorrhages were also observed within the AVM nidus and its surrounding brain tissue. The difference of inflammatory response between two liquid embolic substances may reflect the difference of organic solvents. In conclusion, poly (HEMA-co-MMA) may be a superior embolic liquid for AVM before excision or radiosurgery because of less inflammatory response to AVM's vascular wall.

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We studied 5 patients with retrograde venous drainage of the dural arteriovenous fistulas (DAVFs) with regard to clinical features and treatment. All the cases were examined by detailed angiography and magnetic resonance (MR) imaging before treatment. Two patients presented with intracerebral hemorrhage and 3 patients exhibited progressive neurological deficit. In all patients, large varices were recognized. After transarterial embolization, 4 patients were treated with direct surgery consisting of interruption of the draining vein at the point of exit from the dural wall of the sinus. In these procedures, it is important that the refilling normal venous return was preserved.

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Direct clipping of giant aneurysms of the internal carotid (IC)-juxta dural ring region is considered very difficult. Several methods are currently available for the treatment of giant aneurysms. We describe our experience with the Dolenc' pterional combined epidural and subdural approach and emphasize the technique of temporary trapping of the aneurysms followed by aspiration and collapse, and subsequent clipping. Eight patients presented with 5 giant (>25mm in diameter) and 3 large (15mm to 25mm in diameter) aneurysms of the IC artery in the juxta dural ring region during a 4-year period, manifesting as subarachnoid hemorrhage (SAH) in 5 patients, mass effects (visual disturbance, oculomotor paralysis) in 2 patients, and 1 incidental finding. Preoperative collateral circulation and tolerance to ischemia were studied in 3 patients by the Allcock and balloon Matas tests.
The IC artery in the neck was exposed and catheterized for temporary occlusion during collapse, dissection and clipping of the aneurysm. Standard pterional craniotomy was performed. The posterior orbital roof together with the sphenoid wing, and the dorsal wall of the optic canal and the anterior clinoid process were removed through the epidural approach. Complete opening of the dural ring, and exposure of the surgical genu and axilla of the IC artery were achieved through the subdural approach. Intraaneurysmal blood was aspirated through a catheter placed in the cervical IC artery during trapping of the aneurysm, resulting in collapse of the giant aneurysm and easy dissection of the aneurysm from the surrounding structures. Clipping was then relatively easy with the use of tandem Sugita's fenestrated angled clips. Intraoperative angiography was then performed to confirm aneurysm occlusion.
Postoperative carotid angiography revealed that all 8 aneurysms were completely obliterated by the clip. Transient CSF leakage due to opening of the ethmoid sinus occurred in 1 patient. One patient died of severe delayed cerebral vasospasm. The other 7 patients returned to their preoperative occupations without neurological deficits. The Dolenc' pterional combined epidural and subdural approach is the procedure of choice for IC-juxta dural ring giant aneurysms.

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Dissecting aneurysms in the anterior circulation most frequently involve the middle cerebral artery and the supraclinoid carotid artery. However, spontenous dissecting aneurysms of the anterior cerebral artery (ACA) are extremely rare. We report a case of the dissecting aneurysm of the right ACA inducing subarachnoid hemorrhage (SAH). An extensive search of the literature, revealed only 19 cases of dissecting aneurysm of the ACA to date, and 5 patients, including our case, had SAH. A 58-year-old female suddenly developed loss of conciousness with severe headache. A CT scan showed diffuse SAH. A cerebral angiogram revealed a bulbous post-stenotic dilatation in the right Al portion. The patient underwent a right frontal craniotomy, and a sausage like dilatation was found in the proximal 5-mm segment of the right Al portion. The dilatation was thin and purplish red in appearance. Dissecting aneurysm of the Al was diagnosed from findings of both angiography and operation. The dissecting aneurysm was trapped without arterial reconstruction. Postoperative recovery was uneventful but vasospasm developed. The patient was discharged with slight right hemiparesis three months after the operation.

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We present a surgical case of distal posterior cerebral artery (PCA) aneurysms with the advantages of the posterior subtemporal approach.
A 68-year-old woman had a ruptured left P₃ segment aneurysm, unruptured left P₂ segment and left middle cerebral artery (MCA) aneurysms. On the first day, the MCA aneurysm was clipped with irrigation and washout of dense subarachnoid clots in the left Sylvian fissure. On the fifth day, the left PCA aneurysms were clipped via the posterior subtemporal route. We could easily reach the ruptured aneurysm located in the quadrigeminal cistern along the tentorial surface via the wide space behind the vein of Labbé. After VP shunting, the woman was discharged with no neurological deficits.
This approach to the distal PCA aneurysms provides early observation of the proximal trunk of the PCA, minimal retraction of the temporo-occipital lobe and safe manipulation of the vein of Labbé.

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The internal carotid-posterior communicating artery junction (IC-PC) is one of the most common sites of aneurysm formation. But giant aneurysms arising from this site are very rare. We report a case of giant IC-PC aneurysm with brainstem compression successfully treated by neck clipping.
A 74-year-old female was admitted to our department because of gait disturbance. Neurological examination on admission was normal except for mild swallowing disturbance. CT scan and MR image demonstrated a mass lesion compressing the right cerebral peduncle in the basal cistern. A cerebral angiogram revealed an IC-PC aneurysm on the right side. Therefore, we diagnosed her illness as a partially thrombosed giant IC-PC aneurysm. She underwent right frontotemporal craniotomy followed by neck clipping and thrombectomy with preserved patency of both the anterior choroidal and posterior communicating artery. The postoperative course was uneventful except for transient right occlomotor palsy.

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