Therapeutic occlusion of the vertebral artery (VA) is considered a treatment of choice for unclippable vertebral artery aneurysms and can be achieved with surgical or endovascular intervention. To avoid ischemic complications after treatment, the location and extent of obliteration must be carefully planned. We describe 3 cases of unclippable vertebral artery aneurysms and discuss proper therapeutic options for patients with various vascular structures. Risk of ischemic complications depends on two factors: location of the aneurysm, and the origin of the posterior inferior cerebellar artery (PICA). If an aneurysm is near the vertebral junction and PICA originates at a low position, the perforators probably arise from the long segment between these two structures. VA occlusion above the PICA may cause thrombosis at the stump end of the VA, which would affect the perforators. In this situation, the VA should be occluded below the PICA to avoid subsequent ischemia in the brainstem. The anterior spinal artery, another vital branch from the VA and sometimes visualized on angiogram, should also be preserved. A temporary balloon test occlusion of the VA is a useful adjunct to predict tolerance for ischemia in the basilar artery territory.

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We retrospectively analyzed 12 cases of stroke associated with pregnancy and the puerperium. All cases were surgically treated. We thoroughly discussed outcome of mother and fetus and appropriate treatment. We gave priority to the maternal treatment, resulting in a maternal mortality rate of 8. 3% and a fetal mortality rate of 42%. Seven cases of intracranial hemorrhage due to arteriovenous malformation and moyamoya disease were surgically treated after delivery by cesarean section, with good outcome. On the other hand, outcome of the 3 cases of subarachnoid hemorrhage and cerebral infarction was poor because of the emergency surgical treatment. Management of stroke associated with pregnancy and the puerperium requires comprehensive discussion between neuro-surgeons, obstetricians and anesthesiologists, considering factors such as gestational weeks, emergency surgical indication, possibility of delivery, and social norms.

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We analyzed the change of annual number of extracranial/intracranial (EC/IC) bypass surgeries and carotid endarterectomies (CEAs) in the past 13 years (1986-1998) to clarify the trends and issues of cerebrovascular reconstructive surgery in the near future.
Since 1986, hemodynamic cerebral ischemia has been evaluated by cerebral blood flow (CBF) measurements using single photon emission CT (SPECT). The severity of hemodynamic cerebral ischemia was defined qualitatively using both resting and acetazolamide-activated N-isopropyl-[¹²³I]-iodoam-phetamin (IMP) SPECT in 1986-1994, and stratified quantitatively using both IMP-Autoradiography (ARG) method in 1995-1998. EC/IC bypass surgery was performed on patients who had severe hemodynamic cerebral ischemia. In the quantitative assessment of hemodynamic cerebral ischemia, Stage II ischemia [i.e. resting rCBF≤34ml/100g/min (80% of mean CBF of normal volunteer) and vascular reserve (acetazolamide-activated CBF/resting CBF-1) ×100%≤+10%] was selected for EC/IC bypass, and postoperative changes of resting rCBF and vascular reserve in Stage II ischemia were investigated for establishing the hemodynamic efficacy of surgical revascularization. Otherwise, CEA was performed on patients who had symptomatic or asymptomatic high-grade carotid stenosis (>70%) confirmed by angiogram. Since 1993, percutaneous transluminal angioplasty (PTA) with or without scenting has been used with some patients with symptomatic high-grade carotid stenosis.
In the past 13 years, 432 EC/IC bypass surgery and 146 CEAs were performed. The annual number of EC/IC bypass surgeries decreased gradually since 1988, due to an improvement in determining the severity of hemodynamic cerebral ischemia with the use of CBF-SPECT. In 20 patients with Stage II ischemia, an improvement of both resting rCBF and vascular reserve after EC/IC bypass (STA-MCA anastomosis) was confirmed by IMP-ARG method. The annual number of CEAs was stable in 1986-1997, and increased steeply in 1998. CEAs for asymptomatic carotid lesion has increased in recent years. PTA for symptomatic carotid lesion has gradually increased since 1993 (a total of 27 procedures), but no alternative to CEA has emerged.
Quantitative assessment of hemodynamic cerebral ischemia may show that EC/IC bypass surgery for ischemic stroke is not indicated, but prospective randomized trials concerning Stage II ischemia should be conducted to verify the roles to reduce the risk of stroke relapse. Candidates of CEA or PTA for high-grade carotid stenosis could increase persistently in the near future. Therefore, standard procedures, methods for risk control, and guidelines of CEA, and patient selection and long-term outcome of PTA should be investigated to determine the role of both procedures.

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To elucidate clinical characteristics of ruptured large aneurysm whose diameter ranges from 15 to 24mm, surgical procedures and surgical outcomes of cases with large aneurysms were compared with those with small or giant aneurysms. This study included 827 small aneurysm cases, 62 large aneurysm cases and 16 giant aneurysm cases. Surgical procedures required were significantly different among those groups. Frequency of temporary clip usage, multiple clipping, and cervical carotid artery exposure in the carotid artery aneurysm was related to the size of aneurysms. Surgical outcome of good presurgical clinical grades was poorer in the large aneurysm group than in the small aneurysm group.
This difference appeared to be based on surgical procedures resulting in vascular damage in large aneurysm cases. We should note that some techniques required in giant aneurysm surgery are also necessary for some large aneurysm cases, especially in cases of internal carotid artery aneurysms or vertebrobasilar artery aneurysms. Sophisticated surgical techniques, including skull base approaches, or alternative procedures like endovascular treatment should be considered even for large aneurysm cases to improve surgical results, especially in good clinical grade patients.

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To clarify the characteristics of patients who suffered from thalamic infarction following occlusion of the posterior communicating artery (PcoA) after clipping surgery, we reviewed the records of 68 patients with IC-PC aneurysm who underwent clipping surgery at our clinic in the past 10 years. Of these, 9 cases were selected for evaluation. Occlusion of the PcoA was confirmed on the postoperative angiograms of 8 of the 9 cases, of which 6 cases had no infarct and 2 cases had thalamic infarction. In the remaining patient (Case 9), occlusion of the PcoA was not seen on the postoperative angiograms, but a thalamic infarction was seen on computed tomography (CT). The diameter of PcoA, degree of back flow from the posterior cerebral artery (PCA), and the result of the Allcock test that was conducted in most cases that did not have back flow from the PCA, and size of the aneurysm were each compared in the 9 cases. Cases 7-9 who developed thalamic infarction, had hemiplegia, impairment of impressibility, and clouding of consciousness. Although these symptoms disappeared in Cases 7 and 9, they persisted in Case 8.
The diameter of the aneurysm was over 11 mm in 2 cases who developed thalamic infarction (Cases 8, 9). Of the 6 cases who did not have thalamic infarction (Cases 1-6), the diameter of the PcoA was over 1mm in 4 cases and below 1mm in 2 cases, and back flow from the PCA was seen in 5 cases. The diameter of the PcoA in the 3 cases who developed thalamic infarction (Cases 7-9) was 1mm or greater (1.0, 2.7 and 2.7mm). Case 7 had back flow from the PCA, Case 8 did not have back flow from the PCA but had a positive Allcock test, and Case 9 did not have back flow from the PCA and the Allcock test was not done.
From these results, we concluded that the occurrence of thalamic infarction associated with PcoA occlusion cannot be predicted from the diameter of the PcoA, the presence or absence of back flow from the PCA, or the result of the Allcock test. We assume that occlusion of the anterior thalamoperforating artery, a branch artery of the PcoA, rather than occlusion of the PcoA itself, causes thalamic infarction.

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We reviewed surgery for 40 paraclinoid aneurysms with special interest in the relation between the location of aneurysm and surgical procedure. In cases with small C2 anterior wall and ophthalmic aneurysm, anterior clinoidectomy was not necessary. Anterior clinoidectomy was necessary for clipping of C2 posterior, C2 medial, C2-3 medial, C3 medial aneurysm. In cases with small C2 posterior or medial aneurysm, a contralateral pterional approach provided sufficient operative field for clipping. Adequate clipping for C3 medial and large C2-3 medial aneurysm was not achieved without dissection of the distal ring. Proximal control with balloon catheter placed in the cervical internal carotid artery was safe and useful for temporary occlusion of proximal artery and intraoperative DSA. Intraoperative DSA provided valuable information for correct clipping and complete preservation of the internal carotid artery. Ischemic visual field defect occurred in 2 of 8 cases whose superior hypophyseal artery was sacrificed. Although sacrifice of this artery may be acceptable in cases with large aneurysm involving superior hypophyseal artery, preservation of this artery should be attempted in cases with small aneurysm related with superior hypophyseal artery.

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Of patients in poor neurological condition after aneurysmal subarachnoid hemorrhage (SAH), we have often experienced cases in which grades have improved during a relatively short time after admission. In this paper, we examine changes of neurological grades on 80 patients who did not undergo urgent surgery in the acute stage of Hunt and Kosnik Grade IV and V (Grade IV 30 cases, V 50 cases).
Of the 80 patients, 27 (34%) showed grade improvement after admission. Fifteen (50%) were in Grade IV and 12 (24%) in Grade V. Of the 15 patients in Grade IV, 6 improved to Grade II and 9 to Grade III within 48 hours. Of the 12 patients in Grade V, 2 improved to Grade II, 3 to Grade III, and 7 to Grade IV within 24 hours. All patients were classified as Fisher Group 3 or 4 on the CT scan. There was no relationship between Fisher group and grade improvement. The rate of improvement in 51 patients of the younger group (69 years and under) was 45%, whereas that in 29 patients of the elderly group (70 years and over) was 14%. Of the 27 patients whose clinical course improved, acute surgery was performed in 25 patients and chronic surgery in 2 patients. As for the outcome at discharge, 9 (60%) in Grade IV and 6 (50%) Grade V made a good recovery or moderate disability.
We should closely observe changes in Grade IV ·V patients at least for 24 hours, so that we can perform surgery as soon as the patient's grade improves

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We recently classified non-atherosclerotic cerebral aneurysms unrelated to the branching zones into 4 types based on the status of the internal elastic lamina (IEL) and the intima (10). In the present study, we focused on Type 1-3 non-atherosclerotic cerebral aneurysms (10) without symptoms and with trivial symptoms. Type 1 corresponds to classic dissecting aneurysms, the pathogenesis of which is characterized by acute widespread disruption of IEL without intimal thickening. Patients with Type 1 aneurysms usually have an ominous course. We experienced 95 patients with 99 Type 1 aneurysms. Of the 99 aneurysms, 6 were asymptomatic and 1 presented with minor headache. Initial angiographical findings of the 7 patients were irregular stenosis and all of them “cured” or improved during the follow-up period of 1-4 years.
Type 2 aneurysms are segmental ectasias that have extended and/or fragmented IEL with intimal thickening. Weakness of the arterial wall due to damaged IEL is assumed to be compensated by the intimal thickening. Angiogram of the Type 2 aneurysm shows fusiform appearance with smooth contour. Type 2 aneurysms have no luminal thrombus. The patients with Type 2 aneurysms usually have a placid clinical course. Sixteen patients with Type 2 aneurysms were included, and 15 patients were asymptomatic throughout the follow-up periods of 1-6 years. The other patient presented with facial spasm 6 years after the initial diagnosis due to growing of the aneurysm.
Type 3 aneurysms are dolichoectatic dissecting aneurysms, pathologically characterized by IEL fragmentation, multiple dissections of thickened intima and organized thrombus in their lumen. Angiographically, they have fusiform appearance with irregular contour. Most of them progressively enlarge over time. We experienced 9 patients with Type 3 aneurysm. Of the 9 patients, 4 were diagnosed with trivial symptoms. Of these 4, 3 died of aneurysm enlargement.

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We report the case of a 40-year-old female patient who was considered to have had a dissecting aneurysm (DA) at the C2 portion of the internal carotid artery (ICA) as a cause of subarachnoid hemorrhage (SAH). She suffered from sudden headache and was admitted to our hospital on the next day after onset (Day 1). A CT scan demonstrated SAH in the basal cisterns and the right sylvian fissure, and her clinical condition was WFNS Grade 2. Four-vessel angiography showed no saccular aneurysms but an aneurysmal dilatation, 5.5mm in diameter, with proximal and distal narrowing at the C2 portion of the right ICA. The aneurysm did not have a neck. DA as a cause of SAH was suggested. She could not tolerate the balloon Matas' test at the right ICA on Day 2, and underwent the common carotid ligation and continuous spinal drainage. After a month, she was discharged without neurological deficits. When an aneurysmal dilatation at this portion of an ICA producing SAH is demonstrated, it is important to distinguish DA from other aneurysms such as blood blister-like and saccular ones. DA of the intracranial ICA producing SAH is rare. We review 6 cases including ours and discuss diagnosis and treatment.

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We report the case of a 37-years-old female with a bacterial aneurysm successfully treated. She suffered from infectious endocarditis and presented with a severe headache and convulsion. CT scans demonstrated subarachnoid hemorrhage, and cerebral angiograms showed a fusiform aneurysm at the proximal portion of the superior trunk of left middle cerebral artery. She had right hemiparesis, motor aphasia and disturbance of consciousness due to infectious vasculitis and vasospasm. We trapped the aneurysm right after STA-MCA anastomosis following the recovery from infectious vasculitis and vasospasm. At the operation, we found some subarachnoid empyema on the brain surface. The pathological findings revealed destruction of the elastic band and inflammatory change in the aneurysmal wall. We discuss pathogenesis of bacterial aneurysm and proper timing of surgical treatment.

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We describe the use of continuous hemofiltration (CHF) or continuous hemodiafiltration (CHDF) in 2 perioperative patients with chronic renal failure (CRF) who suffered from intracranial hemorrhage. Because of previous abdominal surgery, continuous ambulatory peritoneal dialysis (CAPD) was not indicated for them.
A 51-year-old female with CRF suffered from subarachnoid hemorrhage. She presented with severe metabolic acidosis that was uncontrollable by washout therapy. CHF improved her severe acidosis without hemodynamic instability, and then she was successfully operated on under general anesthesia. A 69-year-old female with hemodialysis-dependent CRF suffered from right putaminal hemorrhage with ventricular hemorrhage. The patient presented with hyperkalemia and severe hypertension due to water excess on admission. After stereotactic aspiration of the hematoma, CHDF was performed to control water balance and to prevent exacerbation of uremia. During CHDF, the patient developed no symptoms of increased ICP or hemodynamic instability.
Our experience of these 2 cases suggests that CHF and CHDF provide excellent fluid and mineral controls in the perioperative management of the patients with intracranial hemorrhage without increasing ICP or the risk of bleeding.

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