As Takayasu arteritis is a systemic disease with considerable operative risks, strict surgical indication and adequate measures against possible postoperative complications are mandatory. Seventeen patients with Takayasu arteritis (3 males and 14 females aged between 13 and 62) were treated since 1984 in our institute. Sixteen bypass surgeries with saphenous vein grafts were performed in 12 patients, 3 bypass surgeries with synthetic grafts were performed in 2 patients and PTA was carried out in 5 patients.
Postoperative hyperperfusion syndrome was observed in 2 patients whose preoperative angiograms had shown the occlusions of the 4 aortic arch branches, and cerebral blood flow (CBF) analysis had revealed diffuse hypoperfusion. Surgical revascularization should be indicated for those patients who have a significant risk of hyperperfusion syndrome.
Sudden cardiac arrest occurred in 2 patients after reconstructive surgery though preoperative examination in cardiac function could not detect any abnormalities.
CBF study is very useful in the treatment of Takayasu arteritis to determine the liklihood of postoperative complications such as hyperperfusion syndrome. In the postoperative period of surgical revascularization, the incidence of unexpectable cardiac complications should be kept in mind.

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As the embolization of AVMs is often an adjuvant therapy combined with surgical extirpation or radiosurgery, the goal is to optimize the outcome of the following procedure. As the natural history of AVMs predicts a relatively low rate of neurological injury, the combined therapeutic modalities should have a low complication rate. We report the perisurgical complications of 66 AVMs and discuss techniques to avoid complications.
Of the 66 patients treated with endovascular embolization, 14 subsequently underwent surgical resection and 43 had radiosurgery. Four patients obtained total occlusion of their AVM by embolization alone and required no further treatment. In 48 patients, more than 70% of the nidus was occluded with embolization. We observed 3 permanent and 9 temporary complications. Four complications occurred immediately after embolization, due to overembolization or thromboembolism. Seven delayed complications occurred, possibly due to retrograde thrombosis or a chemical reaction to the glue.
In 4 of the 14 cases without AVM obliteration following embolization and radiosurgery, meningeal feeders developed or recanalized after the treatment with absorbable particles. We recommend embolization prior to radiosurgery to treat all fistulous and meningeal feeders and packing of the nidus with non-absorbable embolic materials. In 10 cases, repeat embolization achieved further nidus reduction prior ro repeat radiosurgery.
Intranidal aneurysms that pose a high risk of bleeding were also embolized. To avoid complications with embolization, the AVM angioarchitecture, hemodynamics and functional location should be well recognized. Complications can be reduced with preoperative functional imaging, superselective angiograms, appropriate selection of embolic materials, and appropriate selection of embolization targets. The priority of vessels to be embolized is dictated by the subsequent treatment. Agressive embolization of high-risk vessels or those that will cause abrupt hemodynamic changes should be avoided.

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To evaluate the efficacy of mild hypothermia for the treatment of severe subarachnoid hemorrhage (SAH), we analyzed the outcome of 89 patients who suffered SAH between 1995 and 1999. The patients were divided to 2 groups. Fifty patients who were treated before June 1997 constitute the control group because the cerebral hypothermia was not performed in our hospital in this period. The other 39 patients constitute the hypothermia group. Mild hypothermia therapy was performed for 12 of the hypothermia group, 10 underwent direct surgery and the remaining 2 were treated conservatively.
A target core body temperature of 33-34 degrees C was obtained using a cooling blanket. We aimed at intracranial pressure under 20 mmHg. Eight of the 12 patients treated with hypothermia underwent external decompression, and 7 were also administered thiamyral Na.
The clinical outcome was GR in 1, MD in 4, SD in 1, VS in 3, and Dead in 1 among the 10 patients in the hypothermia group who underwent surgery. Two conservatively treated patients died. The outcome of patients with WFNS grade 1,2,3, and 5 in both groups did not differ statistically. The outcome of WFNS grade 4 patients of the hypothermia group was statistically better than the control group. Symptomatic vasospasam was observed in 40% of the hypothermia patients. The complications of mild hypothermia was observed in all 12 patients, including 10 pneumonia, 8 hyperpottacemia, 8 liver dysfunction and 4 dysfunction of coagulation. Mild hypothermia therapy could be continued in all patients in spite of these complications.
Our study suggests that mild hypothermia for the treatment of severe SAH is effective for controlling ICP and preventing cerebral ischemia, but vasospasm cannot be prevented.

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We treated 37 lesions in 33 patients with intracranial atherosclerotic stenosis by percutaneous transluminal angioplasty (PTA). These lesions included the internal carotid artery in 12, the middle cerebral artery in 7, the vertebral artery in 13, and the basilar artery in 5. Patients were followed angiographically at 3, 12 and 24 months after PTA. The initial success rate was 81% (30/37), and restenosis was seen in 33% (9/27) 3 months after PTA. Seven of 8 lesions treated by second PTA for restenosis were successfully dilated and restenosis was recognized in 3 lesions. Symptomatic complications occurred in 2 cases: 1 was minor stroke caused by a distal embolism and the other was subarachnoid hemorrhage due to arterial rupture. Asymptomatic dissections were observed in 8 of 46 sessions. The morbidity and mortality rate in this series were 2% and 2%, respectively. Based on our results, we discuss the usefulness and indications of PTA for intracranial artery stenosis.

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We analysed the results of microsurgery on basilar-superior artery aneurysms (BA-SCA AN). There were 32 patients ranging in age from 22 to 78 years, and among them subarachnoid hemorrhage (SAH) was noted in 22 patients. Patients with ruptured aneurysm were graded according to Hunt and Kosnik's classification without attendant matters.
Surgery was performed within 7 days after SAH in 13 patients (Grade I: 4, II: 4, III: 2, IV: 2, V: 1), and over 8 days in 9 cases (I: 5, Ia: 2, III: 1, IV: 1).
The pterional approach was carried out on the side of the projection of the aneurysm in all cases. Clipping of the aneurysm was performed in all patients.
Surgical outcome was evaluated by the Glasgow Outcome Scale.
A good result (GR+MD) was achieved in 8 out of 10 patients with unruptured aneurysm, all patients of grade I and Ia, 3 out of 4 patients of grade II, 1 out of 3 patients of grade III and 2 out of 3 patients of grade IV.
Causes of unfavorable outcome were primary brain damage in 2 patients (Grade IV: 1, V: 1), surgical procedures in 2 patients (Grade 0: 1, III: 1), vasospasm in 1 patient (Grade II), muscle weakness due to long-term bed rest in 1 patient (Grade III, 78 years) and incidental disease in 1 patient (Grade 0). The result of microsurgery and causes of unfavorable outcome in cases with ruptured BA-SCA AN are the same as in cases with ruptured anterior circulation aneurysms.
The findings of this study indicate that early surgery is indicated in cases with ruptured BA-SCA AN as in cases with other aneurysms. Concerning the treatment in cases with unruptured BA-SCA AN, plastic coating of the aneurysm should be considered for small aneurysms (2-3 mm of its diameter) and hard-walled aneurysms.

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A new blocking balloon catheter to prevent possible distal emboli during PTA and stenting for the internal carotid stenosis was developed. This catheter was navigated by a 0.014" guidewire to negotiate the tight stenosis or sharp bends that were difficult for the flow control type balloon to pass through. A total of 13 patients were treated with PTA and stenting using this blocking balloon catheter. All cases but 1 received successful dilatation without neurological complications. One case caused stent migration due to improper manipulation of the blocking balloon. We report our method of PTA and stenting using this blocking balloon catheter.

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We characterize the usefulness of diffusion-weighted MRI (DWI) in revascularization therapy of acute cerebral main trunk occlusion. Twenty patients who underwent revascularization therapy were studied: 17 underwent local intra-arterial fibrinolysis (LIF) and 3 underwent embolectomy. Complete recanalization was obtained in 18 of the 20 patients. In the remaining 2 patients, recanalization was partial. Initial DWI in the acute phase was performed 30 minutes to 6 hours after onset, and the DWI findings could be classified into 4 types. In 17 patients with complete recanalization, the hyperintensity areas (HIAs) on the initial DWI were changed to infarctions after recanalization, and in 5 of these patients, infarcted areas became more extended than the initial hyperintensity areas. Three patients with the type 1 finding (no HIA) made good recovery after recanalization and follow-up MRI showed no abnormal intensity, except for 1 patient. In 5 patients with the type 2 finding (HIAs in the perforator's territories), 3 patients with complete recanalization made good recovery, but 2 patients with partial recanalization had a hemorrhagic event in the hyperintensity area on the initial DWI. In 10 patients with the type 3 finding (scattered HIAs in the cortex), clinical outcome of the therapy depended on the location of hyperintensity area on initial DWI. In 2 patients with the type 4 finding (extended HIAs), 1 patient showed clinical improvement and the hyperintensity area on follow-up MRI became smaller than that on the initial DWI. The other patient had a hemorrhagic event with a fatal outcome.
A comparison of clinical outcome between revascularization and conservative therapy group showed the incidence of good outcome was higher in the revascularization groups of type 1, 2 and 3.
DWI could be a useful diagnostic technique for detecting severe ischemic and perhaps irreversibly damaged lesions. The initial DWI provided valuable and reliable information and our proposed classfication of initial DWI findings could be a valuable indicator in the revascularization therapy.

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To contribute to a better understanding of the clipping operation of the basilar superior cerebellar aneurysm, we analyzed clinical symptom and factors influencing the surgical outcome in 58 patients. The patients were aged 22-78 years, with a mean age of 56 years, and there were 36 women and 22 men. Forty-four patients had been admitted because of subarachnoid hemorrhage, and a basilar superior cerebellar aneurysm ruptured in 36 patients. The size of the aneurysms ranged between 2 and 25 mm with a mean of 7 mm. The height of the aneurysm neck was between -5 and 15 mm measured above a biclinoid line with a mean of 7 mm. The pterional approach was utilized in 52 patients and subtemporal in 6 patients. Surgical outcome (Glasgow Outcome Scale) at 3 months after the operation was good recovery in 37 (64%), moderately disabled in 12 (21%), severely disabled in 2 (3%), vegetative survival in 5 (9%) and dead in 2 (3%). The aneurysm size and height of the neck proved to be preoperative factor, which significantly correlated with the surgical outcome. Damage or obliteration of the perforator during clipping surgery mainly resulted in a poor outcome.

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Recently, three-dimensional CT angiography (3D-CTA) is routine and useful examination before aneurysmal surgery, coupled with digital subtraction angiography (DSA). We believe 3D-CTA may show enough anatomical information for most ruptured aneurysmal surgeries. In this study, the surgery was performed using 3D-CTA without DSA.
Between May 1997 and December 1999, 67 patients of SAH (total 78 aneurysms: 64 ruptured aneurysms, 14 unruptured aneurysms) were explored by 3D-CTA. A helical acquisition was performed for computed tomographic scans obtained with a bolus injection of non-ionic contrast medium on Toshiba X vigor/Real. It took only 15 minutes to get the final 3D films in our system.
Examination by 3D-CTA showed 63 cases (94%) clearly developed aneurysms. Three cases were false positive. One of those aneurysms was suspected of being BA top AN. Another was IC-PC AN. The third was AcomA AN. But we could not find those aneurysms in the surgery. We diagnosed those cases as “Unknown SAH.” One case was false negative. The aneurysm located on the distal PICA (1.5%) could not be detected because it was out of the image. In 98.4% of the patients, it was retrospectively though to be possible to perform safe operations with information from 3D-CTA. In 1 case 3D-CTA but not DSA detected MCA aneurysms. In the acute phase of subarachnoid hemorrhage, we could get the information quickly in the severe cases such as Grade IV or V. But 1 aneurysm of MCA reruptured during 3D-CTA due to lack of sedation.
3D-CTA was fast and a mostly safe examination. We concluded that it was possible to perform most ruptured aneurysmal surgeries successfully using 3D-CTA without DSA.

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We report a case in which a radial artery bypass graft was used to treat a basilar artery trunk dissecting aneurysm. The patient, a 73-year-old man, was transferred to our hospital because of disturbance of consciousness. A CT scan on admission showed subarachnoid hemorrhage in the prepontine cistern and interpeduncular cistern (Fisher group II). Left vertebral angiography revealed a large irregular-shaped dissecting aneurysm that extended from the anterior inferior cerebellar artery (AICA) to the basilar artery bifurcation. We decided to perform a delayed operation because the neurological grade was very poor (Hunt & Kosnik grade: V). Follow-up left vertebral angiography 4 weeks after admission showed that the aneurysm had become saccular in shape. A radical operation was scheduled because the risk of rebleeding from this aneurysm was considered to be relatively high. The operation was performed via a transpetrosal approach with the use of VA-RA (radial artery)-PCA bypass. First, the aneurysm was trapped, and then it was clipped because pulse-pressure on perfusion pressure of the superior cerebellar artery (SCA) became almost zero. Postoperative angiography revealed another unclipped aneurysm, and a second operation was therefore performed. Angiography after the second operation showed that both aneurysms had disappeared. Finally, we clipped the saccular aneurysms using a VA-RA-PCA bypass. Monitoring of the perfusion pressure of SCA was very useful for deciding whether to perform clipping or trapping of the basilar artery trunk aneurysm.

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We report the case of a 66-year-old woman with a subarachnoid hemorrhage (SAH) caused by a de novo vertebral artery-posterior inferior cerebellar artery (VA-PICA) aneurysm. The aneurysm had developed within a time span of only 2 years and 7 months. Although she suffered from SAH due to a ruptured left internal carotid artery aneurysm and had received a 4-vessel-angiography 2 years and 7 months before, there was no VA-PICA aneurysm present in the angiogram. In general, hemodynamic changes, hypertension, and congenital anomalies seem to be major risk factors for the formation of an aneurysm. However, this patient did not display such risk factors. In this report, we also discuss the clinical features of de novo aneurysms that are not accompanied by the above-mentioned risk factors. We emphasize the importance of a follow-up angiography. Most reported cases of de novo aneurysms seem to be identified after SAH due to these types of aneurysms. At present, we are able to use a three-dimentional CT angiography (3D-CTA) and magnetic resonance angiography (MRA) more easily and less invasively than a conventional angiography. Therefore, frequent follow-up studies using 3D-CTA and/or MRA are recommended for patients with a ruptured aneurysm.

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