For treatment of unruptured cerebral aneurysm, it is important to identify whether the examined aneurysm has a high risk for future rupture. In this report we analyze the relationship of the shape of aneurysm with the appearance of aneurysmal wall, and consider the risk for rupture.
There were 112 patients with 127 unruptured aneurysms in the past 7 years. We investigated the shape of aneurysm with intra-arterial digital subtraction angiography (IA-DSA) and/or 3 dimentional computed tomographic angiography (3D-CTA). The appearance of the aneurysm in the intraoperative view was also investigated. Thirty-five percent of 127 aneurysms showed an irregular shape. And 66% had a thin-red wall. Irregularly shaped aneurysms were seen in the middle of the cerebral artery (MCA), and there was a high incidence of medium-sized (4-10 mm) aneurysms. A thin-red aneurysmal wall was frequently seen in MCA aneurysms and small-sized (less than 4 mm) ones. Seventy-three percent of the irregularly shaped aneurysms showed a thin-red wall. Relatively, fewer irregularly shaped aneurysms (14%) and thin-walled aneurysms (41%) were found in the juxta-dural ring aneurysms than average. As operative outcome, mortality was 0, and morbidity was 3.6%, both less than those of ruptured aneurysms. There were 14 unruptured aneurysms without surgical treatment, and 5 of them ruptured in follow-up period.
The irregularly shaped aneurysms had a high incidence of thin-red walls and seem to cause future rupture. Preventive surgical treatment is strongly recommended for these aneurysms.

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Therapeutic strategies for patients with multiple occlusive lesions of the major cephalic arteries are still controversial. We examined the therapeutic results of endovascular surgeries for the patients with multiple occlusive lesions of the major cephalic arteries.
Twenty-one patients with multiple occlusive lesions of the major cephalic arteries (internal carotid artery and vertebral artery) were treated with vascular reconstructive surgeries between April 1997 and March 2000. We performed 31 endovascular surgeries (27 stenting, 4 PTA) and 15 surgeries (7 STA-MCA anastomosis, 8 CEA).
Fluctuated symptoms and TIA due to hemodynamic compromise improved in 11 patients, although only 3 patients improved on the NIH stroke scale. Renal functional disturbance occurred after CEA in 1 patient. There were no complications after endovascular surgeries. In the follow-up period, 1 patient developed a minor stroke in untreated arterial territory, and 1 patient died due to heart failure.
Our results suggest that endovascular surgery is a feasible and comparatively safe method in the treatment of patients with multiple occlusive lesions of the major cephalic arteries.

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In surgery for AVMs located adjacent to the interhemispheric fissure, it is often difficult to approach from the ipsilateral side due to obstruction by large drainers to the superior sagittal sinus. The contralateral transfalcial approach is useful for such cases, if the contralateral bridging veins do not interfere with the approach to the interhemisheric fissure along the falx. The main advantage of this approach is that it provides direct access to the main feeders from the anterior cerebral artery and a wider angle of view for dissection of the nidus than that of the ipsilateral approach.
We experienced two cases with an arteriovenous malformation (AVM) located adjacent to the interhemispheric fissure resected using the contralateral transfalcial approach. In both cases, bridging veins as the drainers from the nidus would obstruct the ipsilateral approach to the main feeders from the anterior cerebral artery. The contralateral transfalcial approach was chosen in order to get the main feeders and dissect the nidus in the medial hemisphere. Resection of AVM nidus was successfully done, and postoperatively no neurological deficits remained in either case.

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We have retrospectively analyzed outcome for poor-grade aneurysmal subarachnoid hemorrhage (WFNS Grade IV-V) among consecutive 24 and 36 patients in two periods: 1993.7-1994.6 and 1998.7-1999.6, respectively. In both periods, we aggressively treated them with early surgery, including extensive surgical removal of subarachnoid clot and intracerebral hematoma using a high-pressure irrigation-suction system. In the second period, hematoma removal could be achieved less invasively and more extensively with technical improvements and usage of urokinase in the irrigation fluid. More patients in their 70s and 80s were treated surgically in the second period.
When all patients were compared, the rate of favorable outcome increased in the second period but not significantly. However, among patients less than 80 years old, patients with 6-9 points in preoperative Glasgow Come Scale (GCS) and the WFNS Grade IV patients with Fisher 4 CT achieved a significantly better outcome in the second period. In both periods, patients in their 80s and patients with 3-5 points in preoperative GCS did not show any improvement in overall outcome. Extensive treatment, including extended removal of subarachnoid clot and intracerebral hematoma, helped improve the patients described above, but did not change the overall outcome because of the increased number of older patients and patients in worse grades in the second period.

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A new therapeutic modality should be considered to improve overall results of severe subarachnoid hemorrhage (SAH). Hypothermia has been assumed to be one promissing therapeutic option for severe SAH patients. However, it has not produced acceptable results. We recently developed a new anti-inflammatory neuroprotective therapy with the use of indomethacin (IND) and etodolac (ETD) as a cyclooxygenase (COX) inhibitor.
Between July 1998 and June 1999, 23 severe aneurysmal SAH patients (4 WFNS Grade 4 and 19 Grade 5) were enrolled. IND (6 mg/kg/day) or ETD (16 mg/kg/day) were employed for all patients. Brain temperatures were measured with a ventricle intracranial pressure (ICP) monitor catheter and controlled between 34.5°C and 36.5°C. The CSF samples were obtained from catheter, and inflammatory cytokine (IL1-β) was measured. The patients with uncontrollable ICP or/and brain temperature over 37.5°C were treated by pharmacological brain hypothermia.
The CSF levels of IL-1β were reduced sequentially compared with severe SAH patients who underwent conventional therapy (n=18). The outomes were as follows: good recovery, 3; moderate disability, 2; and severe disability, 3 patients in the Glasgow Outome Scale.
It is concluded that pharmacological brain cooling may impove the outcomes of serious patients by reducing the inflammatory response of the brain after SAH.

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Carotid endarterectomy (CEA) is a well-established procedure for patients with high-grade carotid stenosis. But we sometimes have difficulty in the management of patients with bilateral severe carotid stenosis, most of whom have severe hemodynamic failure in cerebral circulation. These patients can be at risk during CEA because of the possibility of poor collateral circulation during clamping of the internal carotid artery.
We reviewed 8 patients with bilateral severe carotid stenosis and analyzed the safety and efficacy of endoluminal revascularization in this subgroup. We performed carotid angioplasty and stenting (CAS) for one side before CEA of the other side in 4 patients, and CAS for both sides in 3 patients.
The perioperative complications include all strokes within 30 days, 1 patient had transient aphasia after CEA, and 1 patient who was treated by CAS for both sides had transient left hemiparesis after stenting for the symptomatic side. None had permanent neurological deficit periprocedurally.
Although we need long-term follow-up, our data of early experience suggest that CAS for one or both sides of bilateral carotid stenosis can be an effective strategy in the management of this subgroup of patients.

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Near-infrared spectroscopy (NIRS) is a non-invasive methodology that can monitor the change of cerebral oxygenation state continuously. In the present report, we describe our 9 years of experience using NIRS monitoring during carotid endarterectomy in 55 patients, during carotid balloon occlusion test in 16 and during vertebral artery transposition in 4. The results were compared with those of somatosensory evoked potential (SEP), transcranial Doppler sonography (TCD) and single photon emission computed tomography (SPECT). The pattern of NIRS change could be classified into 2 groups: Group 1 showing no change or transient decrease of total hemoglobin and hemoglobin oxygenation and Group 2 showing continuous decrease of these parameters.
N20 amplitude significantly decreased during carotid artery occlusion in Group 2 patients, but did not show any change in Group 1 patients. The mean flow velocity ratio of the middle cerebral artery decreased to less than 38% of the control during carotid artery occlusion in Group 2 patients, but was kept more than 65% of the control in Group 1 patients. Regional cerebral blood flow in the ipsilateral frontal lobe reduced to less than 82% of the contralateral side in Group 2 patients, whereas it was more than 90% in Group 1 patients. Therefore, NIRS could accurately detect critical cerebral ischemia during carotid artery occlusion with good time resolution.
In conclusion, NIRS is very useful to detect cerebral ischemia very quickly and accurately, but a combination of NIRS with other monitoring systems is preferable to enhance the value of NIRS and make up for its limitations. We discuss the usefulness and disadvantages of NIRS for intraoperative monitoring in neurosurgery.

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From July 1971 to December 1998, 1001 patients with subarachnoid hemorrhage (SAH) were admitted to our hospital. Among them, 706 patients received treatment surgically, including 684 neck clippings for intracranial aneurysms. But 17 of these patients (2.5%) suffered recurrent SAH between a 5-to 23-year period (average 14 years) from their previous surgery. To determine the etiology of the recurrent SAH we reviewed all these cases and reevaluated the angiograms taken just after the initial surgery and at the time of the recurrent SAH.
Bleeding was found to be from a de novo aneurysm in 8 cases (47%) and from an enlarged aneurysm that had been too small to operate on earlier (less than 4 mm) in 5 cases (29%). The average period of recurrence was 15.9 and 12.6 years, respectively. The incidence of the recurrent SAH caused by a ruptured de novo aneurysm was 1.3%. The characteristics of patients with de novo aneurysm are: 1) 75% are female, 2) the average time before a recurring SAH is as long as 15.9 years, 3) all are cases of multiple aneurysms, 4) 75% have hypertension. There were close similarities between the cases of multiple aneurysms and de novo aneurysms.
The rupturing of enlarged aneurysm that had been small and unruptured was identified in 5 patients. The time from the previous surgery ranged 7 to 23 years (average 12.6 years). Among them, 4 have hypertension and all are cases of multiple aneurysms.
We can conclude that the cerebral artery of the SAH patients has the potential to develop into a recurring SAH caused by the rupturing of a de novo or growing aneurysms over a long period. And it was suspected that de novo aneurysms are one of multiple aneurysms but develop at a different time. Planned postoperative follow-up angiography to detect newly formed or growing aneurysms should be performed.

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Based on the conclusion of our previous report, we performed follow-up angiography on the 61 outpatients who had undergone neck clippings for cerebral aneurysms more than 5 years ago. According to the findings of the original angiograms, they were classified into 4 groups: Group 1 consists of 34 cases without abnormal finding. Group 2a consists of 14 cases with small, unruptured aneurysms, that were too small to operate on. Group 2b is 10 cases with residual aneurysmal necks after the previous surgery and Group 3 is 6 cases of SAH with unknown etiology.
In 6 out of the 14 cases (44%) from Group 2a, unruptured, untreated small aneurysms had enlarged over an average of 9.8 years. The characteristics of the patients with such aneurysms are: 1) blood pressure under poor control (p<0.05) and 2) 50 percent have de novo aneurysms. Also there was a multiplicity of time and site for aneurysms in these cases.
The enlargement of the residual aneurysmal neck was only found in Group 2b in 2 incomplete clipping cases. As well, the origin of the SAH remained unknown in all cases of Group 3 over a 15.8-year period (on average) before follow-up.
A total of 8 de novo aneurysms were found in 7 cases (3 cases each in Group 1 and 2a and 1 case in Group 2b). The average time before follow-up was 16.2 years. This incidence (11.5%) is considerably higher than the previously assumed rate of around 1 percent. The characteristics of the patients with de novo aneurysms are: 1) 86% female, 2) the average time before confirmation is as long as 16.2 years, 3) all are cases of multiple aneurysms, and 4) 71% have hypertension. There were close similarities between the features of de novo aneurysm and multiple aneurysm cases. These facts lead us to support the hypothesis that de novo aneurysms are one of multiple aneurysms but develop at a different time. As well, patients with aneurysms have the potential to develop into recurring SAH. The best approach to treatment is to do follow-up angiography periodically.

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We report 2 cases of stenting for occlusive lesions due to wall dissection of the intracranial vertebrobasilar arteries. The first case concerns a 58 year-old man who had dizziness due to restenosis, 6 months after balloon angioplasty. He underwent balloon angioplasty for restenosis. The angioplasty was complicated by acute occlusion due to wall dissection. The acute occlusion of the lesion was completely recanalized by implanting a balloon-expandable stent. The second case concerns a 50 year-old man who had progressive ischemic symptoms due to spontaneous dissection of basilar artery. The symptoms progressed in spite of anticoagulation therapy. The lesion was successfully treated with stenting.

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An aneurysm in the 4th ventricle is rare. We encountered a ruptured case, which presented with an intraventricular hemorrhage. The aneurysm neck was located at the choroidal point of the posterior inferior cerebellar artery (PICA), and the dome protruded into the 4th ventricle. This aneurysm was explored via the cerebellomedullary fissure and the telovelotonsillar cleft, and the aneurysm neck was clipped through this fissure without splitting the vermis. Lesions in the brainstem and the 4th ventricle can be approached through the appropriate natural pathway (the cerebellomedullary fissure) without damaging normal tissue. We discuss the surgical approach into the 4th ventricle, including the patient's position.

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