Stroke units (SUs), which have been established over the past few years, are useful for achieving good clinical results and medical economy for stroke patients. We also established an SU in 1996 in cooperation with our neurosurgical department. Although, economic studies on surgery of intracranial aneurysms have considered the significant benefit of a surgical approach to unruptured aneurysms, no studies have been performed to analyze the cost of ruptured aneurysms.
We retrospectively conducted the present study to verify whether the SU has a benefit in terms of cost and patient's outcome. We compared a control (C) group with an SU group in terms of length of time waiting for rehabilitation after admission, the length of stay in hospital and patients' outcome at discharge. The C group comprised 48 ruptured aneurysmal patients who were treated from 1993 to 1995. The SU group comprised 45 patients treated from 1996 to 1998. The SU shortened the length of stay in hospital about 30 days with the same outcome compared with the C group. We calculated in each group the direct cost of hospitalization and the rehabilitation cost during their stay in hospital. The total cost in the SU group was about 500,000 yen less than that of the C group.
The SU helps achieve good clinical results and medical economy even for patients with ruptured aneurysms.

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An increasing number of cases of incidental cerebral aneurysms are currently being reported. However, the indications for surgery of unruptured asymptomatic cerebral aneurysms are still unclear. The benefit of treatment ultimately depends on the relative risk of subsequent aneurysm rupture in untreated patients versus the risk involved in surgery.
We report a series of 90 cases of unruptured aneurysms, admitted and treated over a period of 6 years and 1 month (1993. 12. 1-1999. 12. 31). General information about the natural history of incidentally discovered aneurysms was given to the patients and their relatives. Informed consent was based on the fact that subarachnoid hemorrhage was associated with a poor prognosis, while excellent operative results were common in patients with unruptured aneurysms.
Sixty-six patients underwent surgery, and the remaining 24 patients who did not receive surgery were followed up at periods ranging from 1.5 months to 5 years and 9 months. Of the 66 patients who were operated on, there were 11 (17%) cases of postoperative complications, including 5 venous infarctions, 2 memory disturbance, 1 recurrent cerebral infarction, 1 visual disturbance, 1 cerebral embolism and 1 intraoperative rupture. Three patients (4.5%) did not recover. The remaining 8 patients, however, recovered with time or through treatment. Among the 24 patients who were treated conservatively, only 2 developed rupture of the aneurysms (0.4% annual rupture rate) and both made an uneventful recovery. It is our clinical impression, however, that they harbor an unruptured aneurysm with at least mild trepidation. Aneurysm size, location, and number were risk predictors for surgical morbidity in patients with unruptured aneurysms. This experience suggests that if intact aneurysms are treated surgically, careful preoperative evaluation and precise microsurgical techniques are essential. An endovascular approach or some skull base surgical techniques should be considered to obtain better results.

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Surgical indication for patients who harbor unruptured intracranial aneurysms still remains indefinite. We investigated the management outcome in 150 patients with unruptured aneurysms, to evaluate the benefit of preventive surgery. Twenty-three of the patients had symptomatic aneurysms. Surgical therapy was planned in patients 70 years old or younger with no or mild systemic complications. Ninety-four patients underwent surgery, including 5 endovascular interventions, and conservative treatment was chosen in the remaining 56 patients. In the surgical group, 4 patients (4.5%) became moderately disabled, and 3 patients (3.4%) severely disabled after surgery. No mortality directly related to operation was observed, while 1 patient died of myocardial infarction 4 years after surgery. There was no morbi-mortality after endovascular therapy. Among the patients who underwent conservative therapy, 4 suffered from subsequent aneurysm rupture during the total follow-up period of 155 years. The annual rupture rate was estimated at 2.6%. Clinical decision analysis based on our data demonstrated that preventive surgery is beneficial for a Japanese 70 years old or younger. If the annual rupture rate was set at 0.5%, the expected utility was almost the same in both the surgical and conservative group. Though our surgical indication appears to be valid from our own results, both the estimated risk of rupture and operative results affect surgical indication.

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We evaluated variations of the superficial middle cerebral vein (SMCV) and basal vein of Rosenthal (BVR) by three-dimensional computed tomography angiography (3D-CTA) imaging.
To this end, 3D-CTA images in the axial stereoscopic view and other directions were constructed by the voxel transmission method and maximum intensity projection images were obtained in 600 sides of 300 patients.
The SMCV was classified into 7 courses and drainage pathways, and the BVR into 5 drainage pathways. The drainage pathways of the SMCV were the sphenoparietal sinus or cavernous sinus in 62.8% of sides, the pterygoid plexus in 12.5%, the superior petrosal sinus in 1.5%, the transverse sinus via the middle cranial fossa in 1.8%, the transverse sinus via the temporal squama in 2.2%, and others in 8.2%. The BVR flowed into the great vein of Galen in 87.8% of sides, but the anastomoses between the first and second segments were hypoplastic or aplastic in 37.0% of this type. The deep middle cerebral vein in such cases flowed into the cavernous sinus or sphenoparietal sinus. Therefore, typical BVRs with these anastomoses were present in only 53.3% of sides. More than one-fourth of the typical BVRs also entered the anterior sinuses or veins such as the cavernous sinus. Other outflow patterns were the lateral mesencephalic vein in 5.6%, the peduncular vein in 1.5%, and the lateral or medial tentorial sinus in 5.1%.
Understanding of the embryonal venous drainage pathways is essential to evaluate individual variations in veins. The skull base venous system, which courses medially or laterally and longitudinally, is seen best on axial CT scans. 3D-CTA provides multidirectional stereoscopic images of specific vessels and demonstrates the anatomical relationships with the arteries and the bone structure. Therefore, 3D-CTA is useful for the investigation of individual variations and in preoperative planning for skull base surgery to reduce the invasiveness of surgery.

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Paralytic ileus is one of the most important systemic complications associated with intracranial diseases such as subarachnoid hemorrhage (SAH), intracerebral hemorrhage (ICH), cerebral infarction (CI) and cerebral contusion (CC). A patient who suffers from intracranial diseases including cerebrovascular strokes has a tendedncy to be complicated by a paralytic ileus.²¹⁾²²⁾ In this paper, we present 15 cases with intracranial diseases who suffered from paralytic ileus. Indeed, various factors such as a previous history of an abdominal operation, sepsis, trauma, and drugs may contribute to the mechanism of this complication. On the other hand, nimodipine, a kind of calcium antagonist is an effective hypotensive agent without decreasing the cerebral blood flow. But an administration of this agent sometimes causes a paralytic ileus.¹⁾²⁾ Nimodipine were administered for all the patients of our 15 cases with hypertension. It was suggested that an administration of nimodipine was the most significant factor of the paralytic ileus of our patients. Three patients died of paralytic ileus despite the intensive conservative treatments described as below. So we must pay attention to this unexpected complication when we use this agent for those with intracranial diseases.

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We describe a strategy for carotid artery reconstruction using synthetic graft. Case 1 is 69 year-old man who presented with right hemiparesis. Angiography showed left carotid artery occlusion and right carotid artery stenosis. The subclavian-carotid artery bypass was performed using a knitted double-velour collagen-impregnated graft (Hemashield). Case 2 is 61 year-old woman who presented with a cervical fist-sized mass. The left common carotid artery were encased by thyroid cancer. Radical tumor resection and carotid artery reconstruction were performed using a ringed expanded polytetrafluoroethylene (ePTFE) vascular graft. Case 3 is 72 year-old man admitted to our clinic with complaint of hoarseness of three months' duration. Angiography demonstrated the encasement of the left carotid artery by a laryngeal tumor. Radical tumor resection and carotid artery reconstruction were performed using Hemashield. All reconstructed carotid arteries using synthetic graft have remained patent, and the postoperative course of all patients was good for a followed-up of 20 months (Case 1), 24 months (Case 2), and 10 months (Case 3). Synthetic graft can be performed satisfactorily in carotid arterial replacement with a medium caliber more than 6 mm in diameter.

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We performed endovascular treatment of ruptured intracranial aneurysms with GDC in 11 patients over 70 years of age (ranging from 70 to 89 years old). Hunt & Kosnik grading was II in 2 patients, III in 4, IV in 2, and V in 3, respectively. The aneurysms were located in the internal carotid artery in 4 patients, in the anterior communicating artery in 4, in the posterior inferior cerebellar artery in 2, and in the basilar artery in 1. The approach was transfemoral in 8, transcarotid in 2 and transbrachial in 1. In 1 patient, GDC placement could not be done due to difficulty of catheter placement. Complete occlusion of the aneurysmal body was accomplished in 6 although a small neck remnant was observed in 2. Body filling was observed in 4. Procedure-related morbidity or mortality was not observed. The follow-up period ranged from 2 to 22 months. Recurrent hemorrhage was not observed. In the 7 patients with Grade II, III, and IV, 5 patients showed good recovery or moderate disability. All 3 patients with Grade V died. Cause of death was severe subarachnoid hemorrhage in 3, acute myocardial infarction in 1, and cerebral vasospasm in 1. GDC embolization is a useful therapeutic alternative for treatment of ruptured intracranial aneurysm in elderly patients.

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We report a case of bilateral posterior cerebral artery (P1-P2 junction) giant aneurysms associated with bilateral internal carotid artery occlusions that were treated by surgery and endovascular procedure.
A 51-year-old man suffered from dysarthria and left hemiparesis in June 1997. He was referred to our facility from another hospital for left hemiparesis caused by brain tumor. The patient was admitted to our facility on July 24, 1997. He was alert on admission and neurological examination disclosed dysarthria and mild hemiparesis with sensory loss including the face on the left side. CT-scan revealed high-density mass in the right cerebral peduncle. Cerebral angiography demonstrated 2 large aneurysms arising from the bilateral P1-P2 junction. Bilateral carotid arteries were occluded at 2-3 cm distal from cervical carotid bifurcations. Anterior circulation was supplied with the vertebro-basilar system.
On September 18, neck clipping of the responsible right aneurysm was carried out through the right pterional approach. Postoperatively he had temporary worsening of left hemiparesis but improved. On December 3, embolization of the left PC aneurysm with detachable coils was performed. Postoperative angiography showed disappearance of the aneurysms and good patency of the parent arteries. He was discharged with paralytic gait.
We supposed the change of hemodynamics by the occlusion of internal carotid artery as the cause of the formation and growth of such aneurysms. We discuss the mechanism and therapeutic problems of aneurysmal formation following bilateral carotid occlusion.

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A 51-year-old female was admitted complaining of headache and vomiting. On admission her consciousness was clear, and neurological examination showed no abnormality except for nuchal stiffness. Computed tomographic scans demonstrated subarachnoid hemorrhage (SAH) and a hematoma in the fronto-temporal lobe. However, cerebral angiography revealed neither aneurysmal shadow nor other causes of bleeding. On the day of admission, exploratory surgery was undertaken. Aneurysms or other vascular lesions were not found on the C₁ and C₂ of the internal carotid artery, M₁ and M₂ of the middle cerebral artery (MCA), and A₁ of the anterior cerebral artery, while a small mass 1 cm in diameter was found on a branch of the anterior temporal artery derived from the M₁ segment. Trapping of the feeding and draining vessels was performed and the mass was resected. Histopathologically the wall of the mass was lacking in the media and internal elastic lamina and was composed of lamina interna and adventitia. Inflammatory, tumorous and dissecting lesions were excluded. Postoperative course was uneventful, and the patient was discharged with no neurological deficits.
SAH of unknown etiology is thought to be benign lesions, while some of the patients diagnosed as SAH of unknown etiology occasionally present with rebleeding, and the prognosis is not always good. Exploratory surgery frequently delineates the cause of bleeding in those patients diagnosed as SAH of unknown etiology. However, it is very rate that the angiographically occult aneurysm is located on the peripheral branch of the distal MCA as it was in the present case. Exploratory surgery should be undertaken when aneurysms are suspected to be the cause of bleeding in those patients diagnosed as SAH of unknown etiology. And it is important to investigate not only the main trunk of the cerebral arteries but also the peripheral branches as extenively as possible in the exploratory surgery.

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We review 16 cases of distal posterior inferior cerebellar artery (PICA) aneurysm. Of 2691 ruptured aneurysms in the Nagasaki Subarachnoid Hemorrhage Studying Group Data Bank from January 1989 to December 1998, 15 distal PICA aneurysms (0.6%) were reported. We encountered a case of extracranial distal PICA aneurysm in 1999. Including this case, 16 distal PICA aneurysms were reviewed in this study. Eight patients underwent neck clipping of aneurysm, and GDC embolization was done in 1. Rebleeding after admission appeared in 6 patients (40%): 3 patients of Grade III, 2 of Grade IV, and one of Grade V on admission. The outcome was poor in these 6 patients. All 4 patients of good grade (H & K Grade I and II) and 2 of 5 patients of Grade III underwent neck clipping without rebleeding. Excellent outcomes were obtained in these 6 patients. Furthermore, of 5 patients with Grade V, 2 patients had a favorable outcome. These results suggest that careful management to prevent rebleeding might yield a good outcome even in poor grade patients.

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We present 2 cases of dissection of the bilateral vertebral arteries. A 57-year-old man suffered severe occipital headache. Computed tomography (CT) scan demonstrated no evidence of intracranial bleeding. Magnetic resonance images (MRI) revealed intraluminal thrombus in the bilateral vertebral arteries, and magnetic resonance angiography (MRA) showed narrowing and dilatation of the bilateral vertebral arteries. Cerebral angiography comfirmed the diagnosis of dissection of the bilateral vertebral arteries. Because he had no neurological symptoms, no treatment was administered. Four months later, MRA demonstrated spontaneous improvement of the previous abnormal findings.
Another case was a 38-year-old woman, who suddenly lost consciousness. CT scan revealed subarachnoid hemorrhage. Cerebral angiography demonstrated “pearl and string sign” in the bilateral vertebral arteries, indicating dissecting aneurysms. She was treated conservatively, and her consciousness gradually improved. Fourteen months after onset, she was in good condition without any neurological deficits. On MRA, there has been no change in the abnormal findings of the bilateral vertebral arteries.

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