The Japanese Standard Stroke Registry Study (JSSRS) group (chief investigator: S. Kobayashi) developed new software for its acute stroke database. In our institute, this software was applied within a medical records database system that functioned in a local area network (LAN). From January 1, 2000, to January 31, 2002, 2,068 stroke patients were registered in the JSSRS database, and 1,731 patients' data were confirmed. About 70 patients were registered monthly, and cumulative cases with unconfirmed data were not increased but changed up to a mean 75 cases per month. The third section (medical record manager) should control continuous registration of stroke patients and confirmation of input data.
The JSSRS database was useful for confirming classification of disease, patients' history, and clinical course for other forms in the medical records database. According to the confirmed stroke database, clinical categories of acute brain infarction were classified into cardiogenic embolism in 28.0%, atherothrombotic stroke in 27.4%, and lacunar stroke in 35.3%. Time from stroke onset to admission was within 3 hours in 36%, and within 6 hours in 48%. Accuracy of the stroke database could improve after the introduction of JSSRS database software.
An acute stroke databank based on the JSSRS database could be valuable for establishing evidenced based medicine (EBM) for stroke management and planning of new strategy for acute stroke. In addition, input data for the JSSRS database is useful for confirming and establishing a medical records database.

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To determine the surgical indication of small unruptured intracranial aneurysm, a prospective study (SUAVe Study, Japan) is in progress at 16 national hospitals. These hospitals are observing the natural history of small unruptured intracranial aneurysms (under 5 mm diameter) without surgical treatment.
During 1 1/2 years from October 2000, 287 aneurysms (251 cases) with 49 aneurysms excluded by film judgment committees were registered. After registration, 153 aneurysms were followed 6 months and 75 were followed 12 months. These aneurysms were classified into the following 4 types. Type 1: The aneurysm ruptures within a few days to a few months after formation. Type 2: The aneurysm builds up slowly for several years after formation and ruptures in this process. Type 3: The formed aneurysm keeps growing slowly for many years without rupturing. Type 4: The aneurysm grows to a certain size, probably under 5 mm in diameter, and remains unchanged thereafter. The results were none in Type 1, 2 aneurysms (0.9%) in Type 2, 8 aneurysms (3.9%) in Type 3 and 218 aneurysms (95.2%) in Type 4. The annual rupture rate was 1.8%. Of the 2 ruptured aneurysms, both were multiple. Seven aneurysms were enlarged, 8 were multiple and 1 aneurysm was single. These findings show that the growth rate in the case of multiple aneurysms may be faster than in single aneurysms, and multiple aneurysms may more easily rupture than single aneurysms.

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Recurrent bleedings have been known to aggravate the prognoses of patients who experienced cerebral bleeding attacks related to moyamoya disease. Hemodynamic stress on the moyamoya vessels enlarged as collateral pathways has been attributed to the bleeding episodes. Bypass surgery has been performed for these patients to prevent recurrent attacks by reducing the hemodynamic stress on the moyamoya vessels. However, the preventive effect of bypass surgery against recurrent bleedings has not yet been statistically proven.
To establish the treatment guidlines for moyamoya disease with hemorrhagic onset, 20 Japanese centers have combined to evaluate the benefit of direct anastomotic bypass surgery such as superficial temporal artery to middle cerebral artery anastomosis in randomized patients who have experienced hemorrhagic episodes related to moyamoya disease and who have received either best medical treatment alone or best medical treatment plus extracranial-intracranial bypass surgery. This prospective randomized controlled trial named the Japan Adult Moyamoya (JAM) Trial was initiated in January 2001. Twenty patients have been already enrolled in this study.

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A retrospective review of 65 cases with 75 aneurysms under conservative observation at our hospital during the past 7 years was performed to investigate the natural history of unruptured cerebral aneurysms. The median follow-up time was 2.8 years (47-2,476 days). There were 30 males and 35 females, and the mean age was 61.8. The criteria for decision of conservative treatment were as follows: 1) size of the aneurysms (less than 5 mm): 55 cases (73.3%) ; 2) age (more than 70) : 3 cases (4.0%) ; 3) high surgical risk: 6 cases (8.0%) ; 4) dissent: 2 cases (2.7%) ; 5) location of aneurysms: 8 cases (10.7%) ; 6) poor physical condition: 1 case (1.3%). There were 48 ICA aneurysms (64.0%), 62 aneurysms (82.7%) were less than 5 mm, 8 aneurysms (10.7%) had bleb, 72 aneurysms (96.0%) were asymptomatic, and 37 aneurysms (49.3%) were multiple aneurysms. Three cases were ruptured during the observation period. Two of the 3 ruptured aneurysms were small (less than 5 mm), asymptomatic, and were both multiple aneurysms with bleb. Contrary to previous reports, this study suggests that small multiple aneurysms with bleb may have higher risks of rupture under observation.

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Aneurysms can produce large defects in the parent vessel if the aneurysm tears at the neck of the vessel. We present techniques used to repair a tear at the base of an aneurysm encountered during microsurgical clipping of a ruptured aneurysm.
The repair technique involved suturing and covering the aneurysm with an encircling aneurysm clip. A large tear had destroyed the vessel's tubular structure and therefore an encircling clip alone was insufficient for repair. Two microsuture stitches were placed on the tear, so that a split artery reformed a tubular structure. The temporary clip on the distal internal carotid artery was removed for a moment, allowing the retrograde blood flow to provide the counterforce necessary to maintain the vessel's tubular structure.
An encircling clip was then applied to cover the entire circumference of the lesion. Another technique involved placing needles over a tear and applying clips while avoiding parent artery stenosis. Placing a clip to cover an entire tear resulted in an arterial stenosis but just applying a clip was insufficient for repair. With this guiding needle method, a clip can adequately be placed without parent artery stenosis.
These methods required only a short occlusion time for arterial repair, thus helping avoid ischemic complications. These techniques are useful for repairing an aneurysmal tear at its base, especially if the tear is large.

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We studied retrograde leptomeningeal venous drainage (RLVD) in 20 patients with dural arteriovenous fistulas (DAVFs) with special reference to symptoms, findings of magnetic resonance imaging (MRI) and single photon emission computed tomography (SPECT) and treatment results.
In 11 patients there was an accessory route in the RLVD route that was angiographic evidence into the other sinus as well as the involved sinus. There were no hyperintensity areas on T2-weighted MRI. The 9 other patients did not have the accessory route. T2-weighted MRI revealed hyperintensity areas on the involved side of the brain in these patients. In 5 of the 9 patients, the hyperintense areas disappeared and symptoms improved after treatment. Their pre-operative SPECT study demonstrated hypoperfusion in these areas, and vasoreactivity to Diamox was preserved. In the 4 other patients the abnormal hyperintensity areas persisted and the symptoms persisted after treatment. Their pre-operative SPECT study had shown hypoperfusion, and there was no Diamox vasoreactivity.
In DAVFs patients with no accessory route in the RLVD we consistently observed hyperintensity areas on MRI, reflecting venous congestion. The preservation of Diamox vasoreactivity on SPECT study appears to be a good prognostic indicator.

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Vertebrobasilar insufficiency causes vertigo, motor disturbance, cranial nerve dysfunction, and so on. They are often treated with medication and rarely surgically treated, because diagnosis of vertebrobasilar insufficiency is difficult. We report the methods of surgical operation for vertebrobasilar insufficiency and its result. Twenty-nine patients were admitted to our hospital for operation of vertebrobasilar insufficiency from January 1997 to December 2001. The 12 males and 17 females were aged 42-83 years old (mean 66 years old). Symptoms were vertigo in 18, tinnitus in 6, transient ischemic attack in 4, and no symptoms in 1. Diagnosis was made based on magnetic resonance angiography, three-dimensional computed tomographic angiography, and angiogram. The operative procedure was vertebral to carotid transposition in 8, correction for winding vertebral artery in 2, cervical osteophytectomy in 18, and subclavian artery stenting in 1. In all but 1 case preoperative symptoms improved. The 1 exception was sick sinus syndrome, which was diagnosed postoperatively.
Diagnosis for vertebrobasilar insufficiency was mainly based on neurological examination and radiographic findings, but it was difficult. Evaluating these data, operative indication should be decided.

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The pterional approach is a fundamental technique for neurosurgeons, but difficulty for dissection of the sylvian fissure has considerable variety. Establishment of a safe and adequate technique to dissect the sylvian fissure is essential for all neurosurgeons.
We introduce our operative technique for dissection of the sylvian fissure with the reverse plane view of arachnoid membrane and discuss the efficacy of this technique from an anatomical background.
Dissection of sylvian fissure is started from the distal part, where arteries of the M2 segment are seated and adhesion of the frontal and temporal lobe is not so tight. Exposure of space around arteries of the M2 segment is necessary to obtain a direct view to the plane where the frontal and temporal lobe adhere more tightly with dissection progressing more medially. With the reverse plane view of arachnoid membrane of the proximal sylvian fissure, dissection between the frontal and temporal lobe can be achieved safely with a direct view.
Our surgical technique facilitates dissection of the sylvian fissure and prevents damage of surrounding brain and vessels.

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Vertebral aneurysm surgery and endovascular procedures carry a potential risk of postoperative respiratory disorders. This is because the respiratory centers, which are located in the reticular formation of the ponto-medullary junction, are supplied by perforators originating from the basilar artery (BA), the vertebral artery (VA) close to the VA union, the proximal posterior inferior cerebellar artery (PICA), and the proximal anterior inferior cerebellar artery (AICA).
A retrospective study of 13 patients (7 men and 6 women, mean age 54.5 years, range 21-72 years) surgically treated for vertebral aneurysms during the past 4 years in our hospital was done to determine the relationship between treatment modality and postoperative central respiratory dysfunction. Among our patients, there were 4 saccular aneurysms, 8 dissecting aneurysms and 1 giant fusiform aneurysm; 8 aneurysms were located in the VA between the origin of the PICA and the VA union (including 2 cases whose PICAs were not confirmed by angiography); 4 aneurysms were in the VA-PICA junction; and 1 aneurysm was located in the PICA. Six aneurysms were treated by direct surgery: neck clipping was performed in 3 cases; proximal clipping of the VA at the site distal to the PICA was done in 1 case; trapping was done in 1 case; and trapping with an occipital artery-PICA anastomosis was done in 1 case. Seven aneurysms were treated by endovascular procedure with intra-aneurysmal coil embolization.
Respiratory arrest occurred in 3 cases whose postoperative course was uneventful. Rerupture and medullary infarction were not confirmed by CT/MRI obtained immediately and a few days after the respiratory arrests. However, more than half of the intra-dural VA was occluded proximally from the VA union after the direct surgical/endovascular procedure, which included proximal clipping for a giant fusiform aneurysm in 1 case and coil embolization for dissecting aneurysms in 2 cases. The periods between surgery and respiratory arrest were 10 hours, 4 days, and 32 days, respectively, for the 3 patients. Voluntary respiration eventually resumed in 2 patients.
In the surgical treatment of vertebral aneurysms, the possibility of respiratory complications should be kept in mind even though the early postoperative course may be uneventful. Postoperative respiratory failure can be reversed. Thus prompt diagnosis and treatment under close observation are mandatory, especially in cases with a high risk for postoperative central respiratory dysfunction.

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We evaluated 5 patients with intracranial hemorrhage associated with oral anticoagulant therapy (OACT) over a 15-month period. All patients were taking warfarin. They had a mean age of 69 years (age range, 61 to 78). One patient had suffered from spontaneous thalamic hemorrhage while walking. Each of the other 4 patients had a history of minor head trauma. Three patients' symptoms had progressed slowly and were diagnosed as intracranial hemorrhage more than 12 hours after head trauma. Four patients had intracerebral hematoma and 3 had acute subdural hematoma. Two had both. One had hematomas in both the supra- and infratentorial space.
All patients had been on OACT for less than 5 years. Three of the patients were taking OACT for peripheral vascular disease, (2 of whom received arterial grafts), and 2 who were suffering from cardiac valve disease received bioprosthetic valves. Two patients underwent prosthetic surgery within less than a week, and started OACT only 3 and 4 days, respectively, before having intracranial hemorrhage. Two received bucolome, 2 received antiplatelet drugs and 1 received heparin to support warfarin. Two patients were alcohol abusers. All of their international normalized ratios (INRs) of prothrombin time were higher than 1.5, and 3 of them were higher than 3.0 (mean 3.7). Surgical treatment was selected for 3 patients who showed consciousness disturbance. Vitamin K₂ only, was used for warfarin reversal in the 3 early cases. Fresh frozen plasma (FFP) only was used for 1 patient and both were used for the other 1. Treatment with vitamin K₂ needs more than 24 hours to reverse the effects of warfarin completely. FFP needs less than 6 hours. FFP is more effective for emergency operations.
In the surgical cases, hemorrhage was difficult to stanch while the INR was higher than 2.0, and it was easy when the INR was lower than 1.3. One patient had rebleeding 5 hours after diagnosis of thalamic hemorrhage and died on the same day. Only 1 patient's prognosis was good 3 months after the onset of the hemorrhage. He restarted warfarin 6 days after the diagnosis of intracranial hemorrhage.

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Between August 1996 and December 2001, 81 consecutive patients with 89 carotid stenosis were admitted to our hospital. We evaluated the cross point of carotid stenosis and occipital artery on the carotid angiography. In patients with high cervical ICA stenosis, nasal intubation was performed and the occipital artery and/or ansa cervicalis were cut. In 14 patients, the hypoglossal nerve was dissected freely above the internal carotid artery. In 1 patient whose carotid stenosis extended over the occipital artery, stent placement was performed. Another 72 patients underwent CEA without cutting the occipital artery or ansa cervicalis. The anatomical relationship between the occipital artery and ICA stenosis is a useful landmark whether CEA can be performed easily or not.

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