Recent development of endovascular devices such as balloon catheter and stents enabled neurointerventional treatment of carotid stenosis. We introduce our methods of carotid stenting in this paper. Initially, we deployed stents without protection devices and experienced 3 neurological complications (1 major stroke and 2 transient neurological deficits). After that, we developed a novel protective balloon catheter that occluded the distal internal carotid artery and was navigated under guidewire control. Our second method was to deploy stents after predilataion for the internal carotid stenosis using a smaller PTA balloon catheter and expand the stent under protection. The debri or clot that might appear during post dilation was aspirated and rinsed to the external carotid artery by a catheter introduced from the contralateral femoral artery. This method was applied for 37 lesions; transient neurological deficit due to embolic complication appeared in 1 case during the period of predilation.
Then, we started to use a protective balloon including the process of predilation. Initially, the protective balloon catheter was navigated distal portion of the stenosis under guidewire control. Then the guidewire was retrieved to be detached from the protective balloon catheter at the distal portion of the stenosis. The balloon was inflated at the distal internal carotid artery and a PTA balloon catheter was introduced into the stenotic portion and the stenosis was fully dilated. The guidewire was withdrawn and the occluded lumen of the internal carotid artery was rinsed by saline and debri and clot were washed to the external carotid artery. Then, protective balloon was deflated and the guidewire was introduced into the PTA balloon and PTA balloon was withdrawn. Finally a stent was deployed to cross the lesion. Twenty-four lesions were treated with this method without neurological complication. Postdilation under balloon protection was added only for two of 24 cases. This method was simple and effective to prevent embolic complications.

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We investigated surgical immediate and semi-long-term results of the unruptured aneurysms in 113 patients. Between 1992 and 2000, we operated 110 unruptured anterior circulation aneurysms and 3 unruptured posterior circulation aneurysms. The mean age was 57.7 years, mean aneurysm size was 7.0 mm, and mean follow-up period was 4.7 years. Surgical complication was judged at 6 months, and patients with worsening of Modified Rankin Score of more than II were considered surgical morbidity. Patients were subsequently followed to clarify the occurrence of subarachnoid hemorrhage, aneurysm regrowth and occurrence of stroke other than subarachnoid hemorrhage. Surgical mortality was noted in 1 patient (0.9%), and morbidity was noted in 4 patients (3.5%). Subarachnoid hemorrhage after clipping surgery was noted in 1 patient, accounting for 0.19%/year of occurrence. One patient had recurrence of aneurysms and another had de novo aneurysms. The rate of occurrence of aneurysms after clipping of the unruptured cerebral aneurysms was at least 0.56%/year. Six cases had stroke other than subarachnoid hemorrhage. Especially patients whose aneurysm was found during investigation of ischemic stroke had recurrent ischemic disease at a rate of 4.5%/year. These results indicate the necessity of long-term observation of patients previously treated for unruptured aneurysm.

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A long time follow-up study of a single-institution series can provide reliable information on surgical results of cerebral aneurysms. Therefore, of 840 patients with cerebral aneurysms operated at Niigata Rohsai Hospital, 482 cases were studied to determine the incidence of recurrent subarachnoid hemorrhage (SAH). Seven patients (5 from de novo, and 2 from growth of residuum) developed recurrent SAH at a mean interval of 87.0 months, yielding an overall hemorrhage risk of 0.20% and a hemorrhage risk from originally clipped site of 0.0042% per year. To reveal de novo aneurysms formation and the fate of clipped aneurysms, 128 cases underwent late follow-up angiography and/or 3-dimensional computed tomography (3DCT). Eight de novo aneurysms were found at a mean interval of 96.4 month postsurgery for a annual risk of 0.78% per year. Eight residua were noted, of which 5 enlarged.
We conclude 1) long-term efficacy of aneurysm clipping showed a very high permanent obliteration rate, 2) the patients with aneurysms have a high risk of recurrent SAH, even after a “satisfactory” clipping of the aneurysms, at about 10 times that of the general population. Based on these findings and a review of the reported literature, we suggest the following for optimal late review: 1) 3DCT and/or MRA review is probably required to discover de novo as screening for routine, 2) the necessity of late angiographic study should be weighted with a known residua, 3) closer surveillance of females with multiple aneurysms is warranted more than in males.

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We analyzed the surgical results of patients in their 70s suffering from ruptured aneurysms to clarify the possible factors related to poor outcomes. We also investigated the active life expectancy for patients with good recovery on discharge.
Over a period of 21 years (1978-1998), we surgically treated 144 patients with ruptured aneurysms who were 70 years of age or older. Seventy-nine patients (54.9%) obtained a good recovery, 45 (31.3%) were in a disabled condition, and 20 (13.8%) died. The main reason for disability and death was assessed retrospectively. Moreover, we conducted a follow-up study, including interviews, to determine survival rate, quality of life, active life expectancy, incidence of ADL disability and duration of ADL disability for patients with good recovery on discharge.
Factors of poor outcome for patients in their 70s with ruptured aneurysms were aging itself, a poor grade of SAH, and the aneurysm location (especially distal ACA). Misdiagnoses, operative troubles, postoperative cerebral hemorrhage and infarction were other factors influencing poor outcomes.
For patients having a good recovery on discharge, independence with meaningful activity can extend to 6 years after discharge. The overall incidence of ADL disability for patients in their 70s was 2.4 times higher than that of aged people in Sendai City; however, the duration of ADL disability was shorter than that reported in the Japan control study.

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One aim of this prospective multicenter trial was to determine whether bypass surgery can prevent stroke recurrence in patients with major cerebral artery occlusive diseases and hemodynamic cerebral ischemia determined by quantitative measurement of cerebral blood flow. The other aim was to determine whether improvement in hemodynamic cerebral ischemia by bypass surgery can prevent the progression of neuropsychological disorders or improve neuropsychological function. The subjects were 128 patients who had been enrolled in the study for 27 months from November 1st 1999 to January 30, 2001. Each patient underwent treatment according to the study program, and the 2-year follow-up survey of the patients is now under way. Of 128 patients enrolled in the study, 66 were assigned the medically treated group and 62 to the surgically treated group. Nine patients in the medically treated group and 2 in the surgically treated group reached endpoint. The incidence of stroke recurrence did not differ significantly between the two groups (p=0.0577). The entry to the study will end in March 2002 and the final results will come out in 2004.

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We analyzed patients who developed cerebral infarction along the distribution of the perforating artery after aneurysm surgery in order to learn how to avoid such complications in the future.
Neck clipping of a cerebral aneurysm was performed on 825 patients consecutively. Cerebral infarction along the distribution of the perforating artery was evaluated by a postoperative CT scan. We investigated the incidence of cerebral infarction, its causes, clinical symptoms and prognoses.
Postoperative CT scans demonstrated low-density areas in 35 patients (4.2%). We determined that the responsible arteries were the anterior choroidal artery (9 cases), posterior thalamoperforating artery (3 cases), lenticulostriate artery (7 cases), anterior thalamoperforating artery (7 cases) and recurrent artery of Heubner (9 cases).
The causes were attributed to occlusion due to neck clipping (48.6%), ischemia due to intraoperative temporary occlusion of the parent artery (20.0%), ischemia due to retraction of the perforating artery (17.1%) and direct injury (14.3%). Neurological deterioration appeared in 23 patients (2.8%) and remained in 13 (1.6%).
Cerebral infarction along the distribution of the anterior choroidal artery or the posterior thalamoperforating artery usually caused severe neurological deficit, resulting in a poor outcome. On the other hand, those of the lenticulostriate artery, anterior thalamoperforating artery or recurrent artery of Heubner did not have a serious effect on outcome.
Cerebral infarction along the distribution of the perforating artery was caused by neck clipping as well as temporary occlusion of the parent artery and retraction or injury of the perforating artery. To improve surgical results, it is particularly important to preserve the anterior choroidal artery and posterior thalamoperforating artery.

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We evaluated the clinical features of basal forebrain amnesia caused by obstruction of the perforating artery branching from the anterior communicating artery (A com a.) after clipping of the A com a. aneurysm. Five out of 80 (6.2%) patients who underwent clipping of the aneurysm located at the A com a. using an interhemispheric approach presented basal forebrain amnesia after operation. The course of symptoms was divided into 3 types. The severe type manifests amnesia, disorientation, confabulation, restlessness, insomnia, and wandering for several days after surgery and gradual release from these symptoms but mild amnesia in a few months. The moderate type represents amnesia, disorientation and restlessness, but has recovery without any neurological deficit in a month. The mild type shows transient amnesia for a few weeks.
The severe type included 3 patients whose CT tended to demonstrate focal infarction at the subcallosal area. The moderate and mild type included 1 patient, whose CT revealed no infarction. The patients in the severe type were able to return to previous work or lifestyle, although evocation of long-term episodic memory was somewhat disturbed.
The cause of obliteration of the perforating artery, mainly the subcallosal branch, during surgery was considered as follows: stretching the perforating artery adherent to the rear of the dome after clipping, trapping of the A com a., and a difficulty in confirming patency of the perforating artery running behind the large dome or broad neck, especially when rupture occurred during operation. Therefore, it is important to pay as much attention as possible to preserve patency of a larger perforating artery such as the subcallosal branch during clipping of A com a. aneurysm.

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We present a small series of 3 surgical cases with lateral paraclinoid carotid aneurysms. Since the lateral wall of the internal carotid artery in the vicinity of dural ring is uncommon as a site of aneurysmal origin, little experience has been reported in the literature. Discrepancies were encountered between preoperative prediction and operative findings regarding the location of dural ring. On preoperative angiogram, 2 aneurysms were diagnosed as totally intradural and 1 as partially intradural. At surgery, 1 aneurysm was purely intradural, another 1 had both intra- and extradural component, and the other was located completely proximal to the dural ring.
Difficulties in specifying the location of dural ring, especially the lateral margin, on preoperative imaging studies arise in the fact that the dural ring intersects the internal carotid artery at an oblique angle, which varies from case to case. The origin of the ophthalmic artery on lateral angiogram was an unreliable landmark for the lateral margin of dural ring. One of more useful landmarks is the anterior clinoid process visualized on angiogram before subtraction or 3D-CT. Lateral paraclinoid aneurysms that have a component above the anterior clinoid process are likely to be located entirely or at least partially intradural. Surgery should be preserved for those aneurysms because they are at risk of causing subarachnoid hemorrhage.

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We evaluated the usefullness of superficial temporal to middle cerebral artery (STA-MCA) bypass to prevent of future stroke, including rebleeding or an ischemic event, in hemorrhagic-type moyamoya disease compared with the effects of indirect bypass or conservative management.
We examined 23 patients with hemorrhagic-type moyamoya disease concerning their treatment and clinical course after an initial hemorrhagic episode. The mean age of the patients was 43 years, and the follow-up period was from 0.8 to 15.1 years, with a mean of 9.3 years. Twelve patients were conservatively managed. Among the 11 surgically treated patients, STA-MCA bypass was performed on 6 and encephaloduroarteriosynangiosis (EDAS) on the other 5. Ten patients (43%) presented with an ischemia or rebleeding during the follow-up period. The incidence of future strokes in the patients undergoing an STA-MCA bypass was significantly lower (p<0.05) than that in the patients treated conservatively or with EDAS. A comparison of Kaplan-Meier plots of stroke-free time in the patients treated with direct bypass and those treated conservatively or with indirect bypass showed a significant difference (p<0.05) in favor of direct bypass.
The usefulness of the STA-MCA bypass in patients with hemorrhagic-type moyamoya disease to prevent recurrent hemorrhage or an ischemic event was statistically confirmed.

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We studied how to minimize the brain retraction and preserve the hypothalamic (hA) and Heubner's artery (HA) in clipping surgeries for high-positioned Acom aneurysms with the pterional (PT), orbitocranial (OC), and interhemispheric (IH) approaches using cadavers and in clinical cases. With the PT approach, excessive retraction of the frontal lobe was required to access Acom aneurysms located higher than 10 mm from the anterior clinoid process. Untethering of the frontal lobe (wide split of the sylvian and IH fissure, opening of the basal cisterns and division of the thick arachnoid fibers from the optic nerves and chiasma, etc.) and a gyrus rectus (GR) resection minimized brain retraction and exposed the Acom complex up to 13 mm high. Subpial GR resection was required to avoid injury of Heubner's artery (HA).
Long and excessive retraction of the frontal lobe including the A1 and HA should be avoided to prevent subsequent brain infarction. The OC approach offered much wider and better exposure of Acom aneurysms up to 15 mm high. Sacrifice of the olfactory nerve, if possible, offered access to Acom aneurysms higher than 15 mm even with the PT and OC approaches. The IH approach, preferable for high-located and superiorly-posteriorly projecting Acom aneurysms, could not always offer visual access to the hA running behind the aneurysmal dome. In one such case, the hA could be prepared by placing a small rubber sheat between the aneurysmal dome and the hA.
In safe clipping surgeries for high-located aneurysms, the best surgical approach should be selected according to the aneurysmal height and fundus projection, and great care should be taken during surgery to minimize brain retraction and to prepare the hA, HA, and A1 perforators.

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We performed 74 carotid endarterectomies in 65 patients in the last 10 years. We describe surgical results, complications and follow-up in those endarterectomies. We used internal shunts under barbiturate brain protection in all cases. Using a surgical microscope, we removed plaques as a whole block. Surgical mortality was 2.7%, transient morbidity 5.4% and permanent morbidity was 0% in symptomatic cases. In the asymptomatic cases, surgical motality was 0%, transient morbidity 2.7% and permanent morbidity was 0%. The follow-up disclosed only one case of small lacuna.

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