The pterional approach is widely used for aneurysm surgery. In the pterional approach, the sphenoid wing is removed as much as possible but the orbit is not opened. We developed a new technique by which the sphenoid wing is more completely removed and the superior orbital fissure (SOF) is opened. When the first burr hole, MacCarty's key hole, is drilled, the upper half exposes the dura matter and the lower half exposes the periorbita. After a frontotemporal bone flap is removed, the sphenoid wing and the posterior part of orbital roof are removed and SOF is opened widely. Our new technique is safe, easy to perform and has many advantages such as a wide surgical field.

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The authors encountered 16 cases of intracranial pressure (ICP) monitoring following a stereotactic evacuation of hypertensive hematomas. The patient's ages ranged form 45 to 85 years with 65.8 as the average. The site of hematoma was the putamen (8 cases), thalamus (6 cases), and cerebral subcortical (2 cases). All the patients were operated on within a few days form the onset. The hamatoma size ranged form 10.0 to 78.8ml, with the average of 35.5. The average rate of removal was 61.1%. Mean ICP for 3 days following the operation was kept below 15mmHg in 15 of the cases. This method appears effective for treating hypertensive intracranial hematoma in this aspect. One patient that showed high pressure over 15mmHg has suffered from an obstruction of the urinary tract due to bleeding of the bladder. This trouble was thought to be the cause. A group of patients with hematomas over 40ml before operation (Group A) showed a mean 12.5mmHg, this being statistically higher than that of group with hematomas below 40ml (Group B) that showed a mean 5.0. Cerebral perfusion pressure (CPP) of group A after an operation was 81.5mmHg, which was also statistically lower than that of group B. But there was no statistical significance between patients with hematomas over and below 10 ml after operation.

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The problems of staged treatment for large or high flow cerebral arteriovenous malformations (AVMs) was studied in 15 patients (12 of men, and 3 of females whose age ranged from 12-50 years).
The AVMs were located on the surface of the cerebrum in 8, on the basal ganglia in 5, and on the corpus callosum and cerebellum in 2 patients. They are all categorized as grade III to V by Spetzler's classification, and treated by combined procedures with embolization, feeder clipping and surgical excision. Eleven out of 15 patients had total excision and showed a good outcome. But 2 patients had rebleeding from the residual AVM after the first procedure because of a long interval until the second procedure. One had massive brain swelling after feeder clipping, and one had a severe neurological deficit after embolization. Therfore, careful selection of staged treatment and a short an interval as possible between each stage are important in preventing serious complications in staged treatment for AVM.

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Communicating hydrocephalus is one of the secondary complications of the subarachnoid hemorrhage from ruptured intracranial aneurysms. Possible factors for hydrocephalus were analyzed retrospectively in 183 patients with surgically treated ruptured intracranial aneurysms. The site of aneurysms were anterior communicating artery (54 cases), posterior communicating artery (66 cases) and middle cerebral artery (63 cases). Of the 170 cases, except 13 cases who died in the acute stage, shunts were required in 66 cases (39%) because of hydrocephalus. The incidence of hydrocephalus was significantly higher in those patients who had one or more of the following factors: (1) advanced age, (2) the aneurysm was located near the midline, (3) higher preoperative clinical grades, (4) thick clots on CT, (5) delayed ischemic neurological deficits and (6) a decompressive craniectomy. Surgical results of patients with hydrocephalus were worse than those of patients without hydrocephalus.

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Recently intraaneurysmal thrombosis by microcoils for cerebral aneurysms has been spotlighted because of its easier maneuverability than that of detachable balloons. We report ten cases of intracranial aneurysms in posterior circulation treated with coil embolization. Multiple helical coils were mainly used as the embolic material; flower coils and copper wire were added in some cases. Guglielmi detachable coils were applied in two cases. Complete aneurysmal occlusion was obtained in six cases. The parent artery was patent in all cases. No aneurysms ruptured after the embolization. Distal migration of a coil occurred in two cases, one of which was symptomatic, but there were no other major complications.
The intravascular approach has often been selected for surgically inaccessible aneurysms. It seems to be especially useful for the posterior circulation aneurysms, which are likely to develop serious complications because of their complicated anatomical situation and narrow and deep surgical field. Of various embolic materials, microcoils are more advantageous for aneurysmal embolization than balloons with regard to ease of navigation and guiding, possible with regard to ease of navigation and guiding, possible packing, gentleness for the aneurysmal wall, fewer complications and morbidity, and desirable histopathological reactions. However, usual platinum coils are rarely possible to retrieve and replace when they are inappropriately positioned, and they have a higher risk of distal migration and dislodgement. Detachable coils may resolve these problems according to experimental studies and clinical experiences. Coil embolization appears to be useful for subtentorial aneurysms, and long-term follow-up is needed to appreciate it.

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To clarify the problems in the treatment of dissecting vertebral aneurysms (DVA), ten cases (six with SAH, four with brain stem infarction) were used for this study.
DVA was diagnosed by the typical vertebral angiographic findings of dissecting aneurysm. The posterior inferior cerebellar artery (PICA) was located at the proximal part of the DVA in six, distal in two and at the DVA in two cases. Six cases (four with SAH, two with infarction) underwent intravascular or direct surgery. Four cases (two with SAH, two with infarction) were conservatively treated. Proximal balloon occlusion of vertebral artery (VA) was performed in four cases, proximal VA ligation in one and trapping of DVA in one. After the proximal balloon occlusion, two cases needed additional direct surgery due to the residual or enlarged DVA. In both cases, proximal PICA had been spared at the side of the DVA. In the case of proximal VA ligation, late onset of brain stem infarction occurred, possibly due to the thrombosis of vertebro-basilar artery of the ligated side. The four conservatively treated cases enjoyed uneventful recoveries, and two of them showed angiographical spontaneous resolution of DVA.
Conclusion: Problems in the treatment of DVA are considered as follows. 1) Indication of intravascular or direct surgery: We treated the cases with SAH and obtained almost completely satisfactory results. However, angiographical natural resolution of DVA occurred in two cases. Since the natural history of DVA has not been elucidated, the indication of the treatment including the conservative treatment should be carefully evaluated. 2) Selection of treatment: We recommend an appropriate combination of intravascular and direct surgery. 3) Timing of the treatment: According to the reported papers, rebleeding occurred in the acute stage. However, surgical intervention in an acute stage is impractical because of the development of vasospasm. 4) Complication of the treatment: Thromboembolic complication after the proximal VA occlusion is a difficult problem that remains to be settled.

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Two patients with surgically-excised brain-stem cavernous angioma are reported on. Direct operation was indicated because the angiomas exhibited recurrent hemorrhage and were located adjacent to the cisterns. Both showed postoperative transient deterioration of neurological deficits, which improved several weeks after the procedures. The angioma located at the right cerebral peduncle was totally excised, whereas that at the dorsal pons remained and rebled. Brain-stem cavernous angiomas adjacent to cisterns or to the venrticles should be surgically excised when they exhibit recurrent hemorrhange. Total excision of the lesion with minimal damage to the intact brain is especially required in the direct surgery of the brain-stem cavernous angioma.

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The authors report a case of vertebral artery-posterior inferior cerebellar artery (VA-PICA) aneurysm in a 73-year-old woman with subarachnoid hemorrhage. The PICA originates at the vertebrobasilar junction. The aneurysm, which arose at the site of the origin of the PICA projecting laterally, was successfully clipped through a subtemporal-transtentorial approach. The patient was neurogically intact, but her postoperative life was dependent because of the weakness of her muscle power. Microsurgical anatomy and the surgical approach to the aneurysm are briefly discussed.

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A 21-year-old woman presented with headache, vomiting, dysarthria and mild hemiparesis on the right side. CT scan revealed a round well-circumscribed high density lesion in the ventro-lateral portion of the pons. MRI showed characteristic hemosiderin rim in T₂ weighted image. Twelve days after initial bleeding, she developed conscious disturbance, right hemiplegia, MLF syndrome, left abducens and facial palsy. MRI demonstrated the new hematoma extending from the pons to the midbrain. The suboccipital transvermian approach was employed in an attempt to remove the hematoma and the angioma under monitoring of auditory evoked potential. Histological examination revealed abnormal vessels of the cavernous angioma. Surgical indication of the brain stem cavernous angioma is still controversial, especially in a patient with minor neurological deficits. Refinement of neuroradiological procedures and microsurgical technique may bring about favorable results under a more aggressive approach. However, further investigation of the natural history is mandatory in patients with these lesions.

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The authors developed a liquid material, cellulose acetate polymer (CAP), for direct thrombosis of aneurysms. It is unlikely that any balloon or coil, regardless of its size or shape, perfectly matches the shape of an aneurysmal sac without leaving a remnant of the neck. CAP conforms to the contours of even irregularly shaped aneurysms. The authors report the treatment of two ruptured aneurysms with direct infusion of CAP in the acute stage.

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In this report, we reviewed surgical results, complications and late prognosis of 73 carotid endarterectomies on 63 patients with cervical carotid artery stenosis in the last 6 years. We performed microsurgical endartrectomy with internal shunts and electrophysiological monitoring, such as EEG and somatosensory evoked potentials. Perioperative complications were found in 7 patients (9.6%), cerebral infarction in 4 patients, transient hypoglossal nerve palsy in one, acute hepatitis in one, and pneumonia in one. In 2 patients, thromboembolism, caused by a transient obstruction of internal shunts, resulted in major neurological deterioration. On the other hand, hemodynamic ischemia caused no or minor neurological deterioration in 2 patients who had severe stenosis of the carotid artery and reduced perfusion reserve. In follow-up periods (mean 24.5 months), 4 patients (5.5%) have developed cerebral infarction, ipsilateral carotid artery territory in three (4.1%) and vertebrobasilar artery territory in one. Another patient died of myocardial infarction. We mainly discussed how to avoid perioperative complications, especially cerebral infarction, in this report.

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