A series of surgical treatment is presented of 76 patients with unruptured cerebral aneurysms of anterior circulation. The age of patients varied from 34 to 76 (mean 58.8) and there were considerably more females than males (49 against 27). There were 89 aneurysms and 79 surgical treatments were performed. In 39 patients carotid angiograms were performed because of ischemic cerebrovascular disease, in 22 patients of ruptured aneurysm surgery was performed in two or more stages, and surgery was performed in eight patients of cranial nerve palsy, and in seven patients of trauma or chronic headache.
There were three deaths due to infarction and delayed intracranial hemorrhage within 30 days after surgery (mortality 3.9%). Transient morbidity occured in four patients (5.3%), and parmanent morbidity occurred in two patients (2.6%).
The authors analyze the risk factors for surgical treatment of unruptured aneurysms. They indicate four risk factors for both mortality and morbidity; ischemic cerbrovascular disease, diabetes mellitus, low density area on CT, and arteriorsclerotic changes on angiogram. Another three factors are indicated for mortality: patients over 70 years old, male and aneurysm on middle cerebral artery.
Seven cases of this series had extracranial carotid stenosis in the same side of the aneurysm. Carotid endarterectomy was performed prior to aneurysmal clipping in five patients, and their postoperative courses were excellent. In two patients, clipping was performed prior to endarterectomy and transient morbidity occurred in one. These results suggest that management of cerebral blood flow of ischemic brain may improve surgical prognosis of patients with ischemic cerebrovascular disease.
They also indicate that surgery for an unruptured aneurysm associated with ischemic cerebrovascular disease requires more cautions and delicate operative techniques, and improvement of cerebral blood flow should be tried prior to the clipping of an aneurysm if possible. Surgery on older patient should be performed only in selected cases where the patient has a risk of future aneurysmal rupture.

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During the past 5 years, 16 cases of middle cerebral artery occlusion with sufficient collateral circulation were admitted within 24 hours after onset. Among them, 8 patients were treated conservatively and the other 8 patients were treated with STA-MCA anastomosis in the acute stage. Sequential changes of motor function, speech function and CT findings were investigated in each group, and the clinical effects of acute cerebral revascularization were carefully evaluated.
In the surgical group, 7 out of 8 patients had excellent and good recovery, but only one patient had a fair result due to postoperative complication, which occurred 6 days after operation. On the other hand, half of the 8 patients treated conservatively were left with a severe neurological deficit.
Although no fatality occurred in either group, acute cerebral revascularization was more effective for recovery of motor and speech function in the patients of middle cerebral artery occlusion with sufficient collateral circulation.

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Cerebral blood flow (CBF) and cerebrovascular reserve capacity (CRC) were measured by stable xenon computerized tomography (Xe-CT) and acetazolamide test in 22 patients with cerebrovascular disease before and after extracranial-intracranial (EC-IC) bypass surgery for minor stroke, reversible ischemic neurological deficit, or transient ischemic attack. All patients had occlusive lesions of the major arterial trunk that was shown angiographically.
The patients were divided into four groups according to the preoperative resting rCBF and rCRC. All 4 patients with normal resting rCBF and normal rCRC (Group I) showed no postoperative improvement of both parameters. All 3 patients with normal resting rCBF and reduced rCRC (Group II) showed postoperative improvement of rCRC. One of 4 patients with reduced rCBF and normal rCRC (Group III) showed an increase in rCBF and 2 in rCRC. Of 11 patients with reduced rCBF and reduced rCRC (Group IV), 5 had postoperative increase in resting rCBF and 9 had increased rCRC.
These results suggest that in the preoperative state, Group I has normal hemodynamics and Group II has preserved normal rCBF with vasodilatation. Group III has matched low perfusion without vasodilatation. Group IV has two types of hemodynamic states, i, e, one is a state of misery perfusion and the other is a state of matched low perfusion with vasodilatation.

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Vertebral artery transposition to the common carotid artery (VA-CCA transposition) was used for 60 cases who had vertebral artery stenosis at the origin. Some technical ways were requested for arterial reconstruction in 21 cases.
Eighteen cases had not only vertebral artery stenosis but also ipsilateral cervical internal carotid artery (IC) stenosis (11 cases), contralateral cervical IC stenosis (5 cases), or ipsilateral intracranial IC stenosis (2 cases). Cerebral ischemia by cross clamping the common carotid artery during VA-CCA transposition was anticipated in such 18 cases. To avoid the ischemic complications, combined carotid endarterectomy and VA-CCA transposition. VA transposition to subclavian artery (SA), VA-SA bypass and VA-thyrocervical trunk anastomosis instead of VA-CCA transposition were used.
In 3 cases, the first segment of right vertebral artery was too short for VA-CCA transposition. By unroofing of the C₆ transverse foramen, transposition became possible

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This report reviews the natural courses of misery perfusion in 5 patients with atherosclerotic cerebrovascular occlusion diseases. Cases 1 showed partial improvement and Case 2 showed deterioration of misery perfusion on positron emission tomography (PET). These 2 patients did not show any clinical changes during the follow-up periods. Case 3 showed remarkable improvement of misery perfusion during the 2-year follow-ups, but his neurological condition worsened. The EC-IC bypass improved both in PET and clinical symptoms. Case 4 had a stroke at the region of misery perfusion in PET. Case 5 had a lacunar infarction 2 years after the EC-IC bypass on the opposite side. PET taken one month before the stroke did not show any signs of hypoperfusion in the area of the lacunar infarction. Misery perfusion seems not to be a static but a dynamic condition that can develop into cerebral infarction by some hemodynamic stresses. Cerebral cortical or lobar infarction may occur in the region of severe misery perfusion. EC-IC bypass may prevent impending infarction of the cerebral cortex by improving the regional cerebral blood flow. However, EC-IC bypass will not prevent the lacunar infarction of the basal ganglia or internal capsule.

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This report reviews the cases of thirty-nine patients with cerebral arteriovenous malformations (AVMs) treated by transfemoral therapeutic embolization since our development of ethylene vinylalcohol copolymer (EVAL), a new type of liquid embolization material. The results and complications of these cases are reported. EVAL was used as the first choice on most occasions and polyvinyl alcohol (PVA) particles or platinum microcoils were utilized only as supplements as part of one procedure.
Twenty-four cases out of 39 were cured by partial embolization and following surgical removal of the residual nidus. The other 15 cases were treated by embolization alone. Among these 15 cases, complete occlusion was achieved in one case, 90 to 95% occlusion in two cases, 70 to 90% in one case, 50 to 70% in nine cases, and 30 to 50% in two cases.
Neurological deficits occurred in 11 cases including five transient ones. The occurrence of permanent neurological deficits was 15.4% (6/39). There were no deaths caused by any of the treatments. Rebleeding in the follow-up period after partial embolization occurred in three cases. With these encouraging results, we conclude that EVAL embolization is effective as an adjunctive or radical treatment of cerebral AVMs.

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Cerebral hemodynamics associated with ischemic stroke and hemodynamic changes due to reconstructive cerebral vascular surgery were evaluated using positron emission tomography (PET) on 20 ischemia patients who showed symptoms of internal carotid artery territory and five who had reconstructive surgery. Two cases had STA-MCA anastomosis and three had carotid endarterectomy. In patients with chronic ischemia, hemodynamic disturbance appeared in the border-zone areas. On the three carotid endarterectomy cases, the hemodynamic factors showed improvement postoperatively, though no remarkable improvement was found on two cases of STA-MCA anastomosis.

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Causes of vertebrobasilar insufficiency (VBI) are multifactorial. Compromised vertebral blood flow due to atherosclerotic disease has been clearly outlined and its management fairly well standardized. On the other hand, insufficiency due to extraluminal factors such as osteophytes, fibrous bands, abnormal origin of the vertebral artery, and so forth has also been reported. However, its exact clinical significance is not well known and few attempts have been made to surgically correct this condition. In this report, the authors review recent experience in surgical reconstruction of the vertebral system, focus on the VBI caused by extrinsic extraluminal compression, and discuss the surgical management of this condition.
Fifty-four patients with symptoms of VBI were operated on 59 times. Among them, angiographically definitive evidence of impaired vertebral blood flow caused by extrinsic compression was demonstrated in 14 cases; 8 patients were male and 6 were female (mean age 58.6 years, range 22 to 76 years). At the V₁ segment of vertebral artery, Powers' syndrome was found in 1 case, spondylotic VBI in 9 cases in the V₂ segment, and at the V₃ segment, Bow hunter's stroke in 3 cases and VBI caused by atlanto-axial dislocation in 1 case. For the patient with Power's syndrome, resection of anterior scalene and longus colli muscles, and removal of fibrous band were performed. All 9 patients with spondylotic VBI underwent the same surgical procedures, i.e. uncectomy and unroofing at the vertebral level concerned. For 2 of the 3 patients with Bow hunter's stroke unroofing and fibrous band removal were performed, and C_1/2 posteior fusion was performed for one patient. For the patient with VBI due to atlanto-axial dislocation C₁/C₂ posterior fusion, surgical results were excellent. Vertebral artery flow regained in all cases without morbidity or mortality.
Therefore, unlike artherosclerotic stenosis, impairment of vertebral blood flow caused by extra-luminal factors is thought to be good indication for surgery, which obtained vertebral blood flow restoration safely and reliably.

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The clinical features of asymptomatic cerebral infarction (ACI) were investigated by means of CT and MRI examinations of 1,317 outpatients of the Department of Neurosurgery whose complaints did not involve stroke.
1) The incidence of ACI was 63 of the 1,317 cases (4.7%), but among patients in their sixties or older, the incidence was a high 14.9-19.5%.
2) Of the ACI 63 cases, 25 ACI patients (40%) had histories of primary disease and 15 (72%) had hypertension.
3) In regard to location, ACI was found in the lenticular nucleus, the putamen, the centrum semiovale, and the subcortex in the frontal and/or occipital lobe. There were 44 (70%) cases of single lesions, and 19 (30%) cases of multiple lesions. In 55 cases (87%), the lesions were less than 2 cm in diameter (lacuna).
4) In 15 cases in which both CT and MRI examinations were performed, MRI indicated lesions in 100% of cases, and CT in only 33%.

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Thirty-three vertebral artery (VA) reconstructions were reviewed. Twenty-three patients were symptomatic because of vertebrobasilar ischemic disorder. Various reconstructive techniques were used: VA transposition to common carotid artery (VA·CA) (22), VA·CA+carotid endarterectomy (CEA) (3), VA transposition to subclavian artery (VA·SA) (2), external carotid-vertebral artery anastomosis (ECA-VA) (4), and vertebral artery endarterectomy (VAE) (2). Postoperative arteriograms were obtained in all the patients with 9%occlusion and 91%excellent results (patency rates: VA·CA 20/22 (91%), VA·CA+CEA 3/3 (100%), VA·SA 2/2 (100%), ECA-VA 3/4 (75%), VAE 2/2 (100%). Clinical results were the following: improvement 15/23 (65%) and no exacerbation in symptomatic group, but in asymptomatic group exacerbation was noted in 3 cases of VA·CA+CEA. The conclusions are as follows: (1) VA reconstruction, especially VA·CA, in carefully selected patients, is a safe and effective procedure. (2) The use of internal shunt during crossclamping of CA in surgery of VA·CA for the protection of temporary ischemia is occasionally advised. (3) Temporary ischemia due to the vertebral artery clamping is generally well tolerated in proximal VA reconstructive surgery. (4), In performing a combined reconstructive surgery of VA and CA in one single procedure, special technical care is needed to prevent embolic complication.

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Surgery for ruptured basilar aneurysms has been one of the most difficult procedures. Some attempts were made in our clinics to reduce the technical difficulty and improve the surgical result in cases with ruptured basilar aneurysms. In this paper, the effects of these attempts in 55 cases are reported on. Of the 55 cases, aneurysm located at basilar bifurcation comprised 35 cases, junction of basilar artery and superior cerebellar artery 10 cases and junction of posterior cerebral artery and posterior communicating artery 6 cases. The operations were performed within 3 days in 13 cases, 4-7 day in 7 cases and over 8 days in 35 cases. The clinical grades were 1-II in 37 cases, III in 13 cases and IV in 5 cases.
Unilateral pterional approach was carried out and sylvian fissure was opened widely in all cases. Lamina terminalis was opened in 4 cases (7%) and hypoplastic posterior communicating artery was divided in 11 cases out of 35 cases with basilar bifurcation aneurysm (28%). The internal carotid artery was retracted intermittently by aspirator, which was held by the operator's left hand. A temporary clip was used in 20 cases (36%) and the aneurysm was clipped in all cases except one case in which plastic coating was used.
Excellent and good results were obtained in 33 out of 38 cases (89%) classified in grade I-II, in 5 out of 12 cases (42%) in grade III and in one out of 5 cases (20%) in grade IV. The result was not affected by the timing of the operation in grade I-II cases, but in grade III cases the result was better in cases operated on within 3 days (75%) than in cases operated on over 4 days after SAH (25%). The result was not affected by opening of lamina terminalis, division of hypoplastic posterior communicating artery or use of temporary clip.
From these results, we can conclude that early operation will be indicated in grade I-II cases with ruptured basilar aneurysm using above-mentioned procedures, which are useful to facilitate dissection of the aneurysm easy and to perform complete clipping.

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The results of surgical treatment were analysed in 60 unruptured aneurysmal cases of aged patients (over 65 years). There were 13 males and 47 females. Fifty-two cases had a single aneurysm and 8 had multiple aneurysms. Most aneurysms were located in internal carotid artery (95%). The surgical morbidity rate was 15%, including transient neurological deficits and the mortality rate was 1.6% including systemic complications. Based on these results, it was emphasized that aged patients, with unruptured aneurysms even over 70 years old, can tolerate aneurysmal surgery, if the bridging veins are carefully preserved, the brain is carefully retracted during surgery and if patients with poor clinical conditions and ischemic lesions are excluded before surgery.

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Procedure with combined embolization and stereotactic radiosurgery using linear accelerator was performed on four patients of cerebral arteriovenous malformations (AVMs). The nidus of two patients was reduced to a proper size for radiosurgery by embolization using EVAL, one of these cases was cured 8 months after irradiation and another one had partial obliteration of the nidus 4 months after irradiation. In the other patients with only minimal change of embolization, no obliteration of the nidus was seen 5-7 months after radiosurgery.
Combined embolization and radiosurgery is considered safe and effective therapy of large AVMs.

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