Between 1987 and 1995, 10 patients with giant intracranial carotid aneurysms were surgically treated in our department. Three patients with carotid cavernous aneurysms (all 3 patients presented with cranial nerve dysfunction and tolerated balloon test occlusion) were treated by either common carotid ligation or internal carotid ligation. After treatment the symptoms resolved and MRI demonstrated the gradual disappearance of the mass.
The other 7 patients, including 4 carotid ophthalmic aneurysms, 2 carotid posterior communicating aneurysms and 1 carotid bifurcation aneurysm (3 patients presented with progressive visual loss, and 4 patients presented with subarachnoid hemorrhage) were treated by direct clipping. Four patients had visual loss preoperatively; in 3 patients in which the aneurysms were clipped via Dolenc's intra-extradural combined approach the vision was improved, and in the other patient with conventional pterional approach it was made worse. Direct clipping always required temporary clipping of the aneurysmatic vessels.
Three patients without angiographic cross-filling across the anterior communicating artery who had a relatively low stump pressure at the balloon test occlusion, suffered postoperative cerebral infarction; 1 of them died and 2 remained moderately disabled.
Surgical strategy should be considered in each patient according to the stage of individual collateral circulation.

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We present 3 cases of acute subdural hematomas as a result of ruptured intracranial aneurysm. Acute subdural hematoma is a recognized but unusual complication of intracranial aneurysmal rupture. And rupture of intracranial aneurysm should be considered the source of hemorrhage in patients showing acute subdural hematoma without a history or signs of trauma. If the case is not rapidly fatal, conventional angiography is indicated as soon as possible to rule out aneurysm, AVM or other source of intracranial bleeding.
The management of the patient poses a dilemma if the case shows rapidly fatal intracranial hemorrhage. Even the presence of slight SAH at the basal cistern strongly suggests the existence of ruptured aneurysm, but aneurysmal clipping without angiography should be avoided judging from the poor results in previous case reports. Our recent experience suggests that, at the present time, immediate MR angiography is a time saving and promising examination for such patients.

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We report a series of surgical treatment for anterior communicating artery (Acom. A) aneurysm with fenestration. A preoperative angiogram is a must for demonstrating Acom. A, because around the Acom. A there are many perforating arteries seen crossing. Also when there is an abnormality of Acom. A, for example fenestration, duplication and etc., it is not clearly seen. It is a well-known that fenestration has a lack of arterial media and is potentially weak, so an abnormal blood flow has taken place and an aneurysm has occurred at the point of fenestration. For the cases where aneurysms with fenestration cannot be seen by angiogram we have succeeded in using a 3D-CT to show the point of fenestration.
It is necessary to determine an accurate surgical approach because in Acom. A with fenestration the space for moving is very limited. To get a good operative view when an aneurysm is anteriorly placed, it is better to approach from behind the A2 side.
If an aneurysm is posteriorly placed, it is better to approach from the front of A2.
We treated 5 Acom. A with fenestration and report 4 of them.

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Infraoptic course of ACA is a rare vascular anomaly, in which the A1 segment of the ACA shows either aplasia or hypoplasia, while an anomalous arterial branch originating from the medial side of the internal carotid artery near the origin of the ophthalmic artery, runs medially under the ipsilateral optic nerve, then turns upward between the optic nerves to flow into the A-com complex.
We report our experiences of 4 patients with this anomaly, including 3 cases with ruptured aneurysms in the A-com A complex. Neck clipping was performed either through pterional or interhemispheric approach.
We emphasize in this report that the interhemispheric approach has some advantages over the pterional approach to aneurysms around A-com A complex associated with this rare vascular anomaly.

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We report a transcallosal interfornicial approach to a high position basilar bifurcation aneurysm considered to be unapproachable by conventional pterional or subtemporal techniques.A 68-year-old female suffered from headache followed by loss of consciousness. On admission, her Glasgow Coma Scale (GCS) was 6 and a CT scan revealed massive intraventricular and subarachnoid hemorrhage. Right vertebral angiography showed a high position basilar bifurcation aneurysm with a neck located 18mm above the posterior clinoid process. Six days after the emergent external ventricular drainage, the patient was operated on via a transcallosal interfornicial approach. On inspection of the third ventricle base, the aneurysm appeared to have gradually grown into the third ventricle. Following careful identification of perforating arteries, the aneurysm was successfully clipped with two Sugita clips. Postoperatively, consciousness disturbance persisted with serum electrolyte imbalance, which had been present even before the operation. Finally the patient remained in a severely disabled condition.
Despite the advent of microsurgical techniques, surgery for basilar bifurcation aneurysms, especially for high position aneurysms, remains a challenge. Compared with conventional techniques, the transcallosal interfornicial approach offers a spacious surgical field, an excellent view of perforating arteries, and less retraction of frontal or temporal lobe. On the other hand, this approach may possibly damage the peculiar neural or vascular structures including cortical bridging veins, corpus callosum, fornix and the third ventricular floor. We conclude that this special technique can be a surgical option for high position basilar bifurcation aneurysms if the following criteria from radiographical findings are met. (1) The neck of aneurysm is about 20mm above the posterior clinoid process. (2) The aneurysm seems to reside within the third ventricle or damage the third ventricular floor. (3) Sufficient interhemispheric space can be obtained without damaging cortical bridging veins.

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We compare the results of detachable coil embolization with those of surgical clipping in patients with basilar tip aneurysms.
Surgical clipping was performed in 13 patients (SAIL 11 cases, associated with other ruptured aneurysm: 1 case, incidental: 1 case). The aneurysms varied in size and included 12 small ones and 1 large one.
Permanent and/or transient neurological deterioration were observed in 11 cases after operation. Clinical outcome at discharge postoperation showed good results in 6 patients, moderate deficits in 5, severe deficits in 1, and 1 death.
Twelve aneurysms were treated by embolization with Guglielmi detachable coil and Interlocking detachable coil under local anesthesia (SAH: 3 cases, associated with other ruptured aneurysm: 3 cases, ischemia: 2 cases, incidental: 4 cases). Eight were large, 2 were giant and 2 were small. Neurological deterioration was observed in 2 cases.
No perforation on the procedure occurred. Two coil compactions and 1 posttreatment enlargement were observed.
Endosaccular embolization is less invasive than surgical clipping in cases of basilar tip aneurysms. Embolization with detachable coil in ruptured basilar tip aneurysm cases at an early stage may improve clinical outcome.

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We investigated clinical characteristics and operative results in 7 patients with aneurysm arising from the anterior (dorsal) wall of the intracranial internal carotid artery. They were 1 male and 6 females and their ages ranged from 27 to 69. Six of the 7 patients presented subarachnoid hemorrhage of various clinical grades, while an aneurysm was found incidentally in 1 patient. Angiography showed a saccular aneurysm in 3 cases, but demonstrated only a little protrusion from the arterial wall (semifusiform type) in 4 cases, of which 1 required a repeated angiography for the exact diagnosis. Two patients had a coexisting unruptured aneurysm on the same side. Five patients underwent clipping operation within 2 days of hemorrhage. Operative findings disclosed not only a fragile aneurysmal neck in every patient but also thinning of the arterial wall itself in some patients. The aneurysmal clip was principally applied parallel to the internal carotid artery, including the normal arterial wall, and the arterio-aneurysmal complex was totally wrapped with the Bemsheet or muscle fascia. The aneurysm was completely obliterated by a single clipping procedure in 4 patients including 1 with unruptured aneurysm. One patient showed regrowth of aneurysm at the superior-medial portion of the clipped aneurysm on the day after the first operation, and presented recurrent hemorrhage from enlarged aneurysm 14 days later. In a second operation, because of a large laceration at the aneurysmal neck, an angioplasty by suturing the remaining arterial wall was required. Premature rupture was also encountered in 2 other patients. Although hemostasis was accomplished by re-clipping procedure in 1 of the 2 patients, the other patient required arterial suture for angioplasty. The outcomes of 2 patients with angioplasty were extremely poor.
Based on these results, aneurysms of the anterior wall of the intracranial internal carotid artery (IC) should be definitely distinguished from the other aneurysms, since they show outstanding clinical characteristics such as a rapid growth or regrowth within short periods, a vulnerable neck liable to rupture and a broad neck difficult to be repaired when lacerated.
Although most IC anterior wall aneurysms may be successfully clipped by applying the clip blade parallel to the parent artery, the arterial wall around the aneurysm should be completely wrapped to prevent the aneurysmal regrowth. When the aneurysmal neck is too broad to reconstruct the arterial wall by clipping, trapping of aneurysm with a high flow shunt is recommended.

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We present 24 cases of intracavernous giant aneurysms which we have treated so far. All the cases were unruptured and showed neurological signs such as ocular movement disorder and visual dysfunction. There were 11 males and 13 females and the age of the patients ranged between 11 and 75 years (mean 51 years). The follow-up periods were between 6 months and 19 years (mean 6.7 years). Among the cranial nerves, the abducens nerve was affected in 17 cases, oculomotor nerve in 11 cases, optic nerve in 6 cases, trigeminal nerve in 5 cases and trochlear nerve in 4 cases. In addition to conventional angiography, balloon test occlusion (BTO), slow injection angiography, aneurysmorraphy and SPECT with BTO were used to determine a method of treatment. Treatment options were as follows; nonsurgical treatment in 4 cases, common carotid artery ligation (CC ligation) in 7 cases, internal carotid artery ligation (IC ligation) in 2 cases, STA-MCA anastomosis with IC ligation or IC trapping in 6 cases, high flow vein bypass with IC ligation in 3 cases and direct clipping in 2 cases. Although only 2 cases showed early and late ischemic complications, other cases demonstrated improvement of cranial nerve dysfunction relatively soon after treatment and long-term prognoses were good. We conclude that selecting an adequate surgical treatment by using sophisticated diagnostic methods plays an important role for obtaining good outcome for intracavernous giant aneurysms.

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We present an option for controlling the intraoperative premature rupture during an acute aneurysm surgery. The patient is a 47-year-old female who suffered severe headache and soon became comatose. A CT scan on admission revealed massive hematoma in the right sylvian fissure and temporal lobe as well as severe subarachnoid hemorrhage. Angiograms showed a small aneurysm at the ophthalmic segment of the right internal carotid artery. Emergency surgery was performed. At surgery, before the internal carotid artery and the aneurysm were fully dissected, premature rupture occurred. The internal carotid artery was temporarily clipped and the bleeding point was identified. A small piece of cotton was placed on the ruptured point and pressed with a tapered brain retractor, which was connected with the self-retaining retractor, to control the bleeding. Dissection around the aneurysm was carried out with the internal carotid artery to be patent. After the aneurysm and the internal carotid artery were fully exposed, the retractor was released after temporary clips were placed on the internal carotid artery again. Then the aneurysm with ruptured site was wrapped because the aneurysm was so small.
This method, which we call “reverse compression method,” is a useful option for controlling the intraoperative premature rupture of the aneurysm or bleeding from the parent artery, although it is not always applicable.

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Microsurgery of aneurysms that arise in the paraclinoid region remains a formidable challenge to most neurosurgeons. The intricate anatomy related to the internal carotid artery at the site where it leaves the base of the skull to enter the subarachnoid space is responsible for most of the drawbacks of aneurysm surgery in that area.
The planning of the operative strategy requires that one considers some major issues involved with the management of paraclinoid aneurysms, i.e., those related to the anatomical relationships of the paraclinoid area, the characteristics of the aneurysm itself, the choice of the best surgical approach, the site for proximal control of arterial bleeding, and the possibilities for either the improvement or for the arrest of visual deterioration.

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The purpose of the study was to investigate recent treatment of cerebral aneurysm in Japan. A questionnaire consisting of 17 questions was sent to the 959 category A and C neurosurgical institutes in Japan. Five hundreds and twenty institutes responded to the questionnaire (54.2%). Approximately 13,000 patients and 4,700 with and without treatments respectively during the year 1995 were submitted to the investigation.
The average operative case number per institution was 25. The incidence of giant aneurysms was 2.9% and that of dissecting aneurysms was 2.4%. Clipping was performed in 90.3% of the aneurysms, wrapping or coating in 5.2%, proximal ligation or trapping in 1.6%, bypass surgery in 0.7%, and intravascular surgery in 2.3%. Sugita's clip was preferentially used in 80.5% of the institutes. The anterior communicating artery aneurysms and the basilar bifurcation aneurysms were approached dominantly through the pterional route in 80.9% and 88.3% of the institutes, respectively.
The results well delineate the current status of treatment in cerebral aneurysms in Japan. We needed to continue to provide the best treatment for each patient with the aneurysms.

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We report the results of gamma knife radiosurgery for intracerebral arteriovenous malformations (AVM) in our hospital.
One hundred sixty patients with AVM treated by gamma knife have been followed up by angiography over the past 3 years. The complete occlusion rates of AVM were analyzed by the size and location of AVM and the peripheral dose of the nidus. We also report the side effects, rebleeding and re-treatment cases.
Over all complete occlusion rates were 44% at 1 year, 76% at 2 year and 86% at 3 years after treatment. Regarding the size, the occlusion rate in the group where the diameter of the nidus was within 2 cm was higher than in the group with AVM-diameter greater than 2 cm. Regarding the location, the occlusion rate in the brain stem group was less than that in the other group. Regarding the peripheral dose, the occlusion rate in the group receiving a dose of 20 Gy or more was higher than in the group with a dose less than 20 Gy. As the side effects of gamma radiosurgery, there were 4 cases of radiation necrosis (1.3%) and only 7 rebleedings (2.3%). Eleven cases had re-treatment 3 years after the first radiosurgery. The complete occlusion rates were high in the small-size group (less than 2 cm), when AVM was not located in the brain stem, and when the dose was higher than 20 Gy.

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