Ryuta Suzuki

Saccular Aneurysms of the Distal Anterior Cerebral Artery

We report a series of 42 consecutive patients with aneurysms of the distal anterior cerebral artery (ACA). Of these, 36 patients had one aneurysm, 5 had two aneurysms, and one had three aneurysms. Thirty patients had a ruptured distal ACA aneurysm; among these patients, the size of the aneurysm was less than 5 mm in diameter in 20, 6 to 10 mm in 7, and larger than 11 mm in 3. Eighteen patients (42.9%) had multiple aneurysms, and distal ACA aneurysms were responsible for a subarachnoid hemorrhage in 10. Thirty-four patients underwent direct surgery, and 30 of these had excellent outcomes 3 months after surgery. The treatment of patients with distal ACA aneurysms is often technically difficult, because of their broad neck configuration and the coexistence of other aneurysms. Nevertheless, the present study emphasizes that distal ACA aneurysms tend to bleed, irrespective of their size, and that excellent outcomes are obtainable by direct surgery.

Surgically induced angiogenesis to compensate for hemodynamic cerebral ischemia.

Background and Purpose The ischemic brain may stimulate angiogenesis to compensate for impaired circulation. We examined the conditions promoting such angiogenesis to provide the basis for surgical treatment. Methods The degree of cerebral hemodynamic stress was studied in patients with moyamoya disease using the stable xenon-enhanced computed tomographic acetazolamide tolerance test and positron emission tomography. Patients were subjected to surgery in which scalp arteries were placed on the cerebral cortex without vessel-to-vessel anastomosis. Formation of the newly vascularized collateral network connecting the implanted artery to cortical arteries was assessed angio-graphically 12 to 17 months after surgery. Results Preoperative average resting cerebral blood flow for cortex that developed revascularization of cortical arteries was not significantly different from that for cortex that did not. However, cortex that developed revascularization had an average preoperative increase of blood flow by acetazolamide tiveincreasetreatment of −3.29±4.6 mL/min per 100 cm3 (n=20), which was significantly less (P=.0034) than that of cortex that did not show revascularization (20.7±4.3 mL/min per 100 cm3; n=9). Good revascularization developed when the cortex showed increase of blood flow by acetazolamide treatment of less than 0 (steal phenomenon). Preoperative positron emission tomography data indicated that revascularization developed when the cortex was under “misery perfusion.” Postoperative hemo-dynamics were ameliorated by revascularization. Conclusions Angiogenesis to connect the implanted scalp arteries to the cerebral cortical arteries was selectively initiated when ischemia of hemodynamic origin existed.

The role of superoxide anions in the pathogenesis of cerebral vasospasm.

Background and Purpose To determine the role of superoxide anions in the pathogenesis of cerebral vasospasm after aneurysmal subarachnoid hemorrhage, we studied the preventive effect of human recombinant copper‐zinc superoxide dismutase (h‐r SOD) in a rabbit subarachnoid hemorrhage (SAH) model. Methods Forty‐five rabbits receiving intracisternal injection of 3 mL autologous nonheparinized blood or 3 mL saline were divided into four groups as follow: (1) saline injected and no treatment (control group, n=6); (2) blood injected and no treatment (SAH group, n=20); (3) blood injected and treated by multiple intracisternal injections of 30 000 U of h‐r SOD in 0.5 mL saline (SOD group, n=9); and (4) blood injected and treated by multiple intracisternal injections of 0.5 mL saline (saline group, n=10). Serial angiograms were performed after the blood injection, and the diameter of the basilar artery was measured. Three animals from the control group and five animals from the SAH and SOD groups each were killed 2 days after SAH, and their basilar arteries were processed for transmission electron microscopic observations. Results In the SAH and saline groups, the diameter of the basilar arteries was significantly reduced (28±14% and 27±9%, respectively) at 2 days after the blood injection, then recovered to pre‐SAH levels until 11 days. In the SOD group, the diameter of the basilar artery was only minimally changed during the follow‐up period. Transmission electron microscopy revealed endothelial injury in all basilar arteries in the SAH group, whereas endothelial injury was minimal in the SOD group. Conclusions We determined that h‐r SOD prevents the occurrence of vasospasm, possibly as a result of preventing endothelial injury initiated by superoxide anions. (Stroke. 1994;25:864‐868.)

MENTAL OUTCOME FOLLOWING ENCEPHALODUROARTERIOSYNANGIOSIS IN CHILDREN WITH MOYAMOYA DISEASE WITH THE ONSET EARLIER THAN 5 YEARS OF AGE

The mental prognosis of children with moyamoya disease, in whom the onset was when they were younger than 5 years of age, has been reported to be very poor. We studied the mental outcome of these patients after encephaloduroarteriosynangiosis (EDAS) in relation to the age at the onset of the disease and the age at operation. For patients in whom the onset of moyamoya disease occurs when they are younger than 2 years of age, the prognosis is very poor with regard to mental abilities even if they have an operation within a year after the onset. Slight hope remains if the operation is within 3 months of the onset. For patients in whom the disease begins when they are 2–5 years of age, EDAS performed before the age of 9 years may result in a good outcome with regard to mental ability, as well as resolution of the paroxysmal symptoms and crebral revascularization.

Changes in cerebral hemodynamics following encephalo-duro-arterio-synangiosis (EDAS) in young patients with moyamoya disease☆

To evaluate the effect of encephalo-duro-arterio-synangiosis, (EDAS), we obtained follow-up angiograms and measured regional cerebral blood flow in 21 young patients with Moyamoya disease. Carotid fork stenosis continued to progress after EDAS, although angiography demonstrated a marked increase in the number of middle cerebral artery branches via implanted arteries. Preoperative cortical blood flow was lower than normal. The post-EDAS increases in hemispheric and cortical flow were significant in patients with transient ischemic attacks, but not in patients with infarction. The increase in cortical flow at the site of EDAS was first noted 2 weeks after EDAS.

Perioperative complications of encephalo-duro-arterio-synangiosis: Prevention and treatment

We performed encephalo-duro-arterio-synangiosis on 169 sides of 81 Moyamoya and 8 non-Moyamoya patients in the past 10 years. The advantage of this operation is its minimal operative invasion, giving rise to few operative complications. During 10 years of practice, however, we encountered some perioperative problems. Perioperative cerebral infarction of varying severity was seen in six Moyamoya patients. Severe hyperventilation with crying was the main trigger of infarction. Two patients developed wound infection with Gram-negative rods. Removal of an infected bone flap was necessary. One Moyamoya patient developed malignant hyperthermia during the operation. One acute epidural hematoma necessitated an emergency hematoma removal. Five patients showed a temporary aggravation of involuntary movements. Prolonged mild fever and temporary and limited hair loss around the wound were often observed. Cases and their treatment are presented with discussion of preventive measures.

Microphysiology of Selectively Vulnerable Neurons

Publisher Summary This chapter describes the changes of neuronal function and other physiological parameters. A common carotid artery (CCA) occlusion in Mongolian gerbils, as well as regional differences of these parameters is also described. In a method described in the chapter, bilateral CCA occlusion produces severe ischemia in both cortex and hippocampus. During CCA occlusion, the forebrain reveals severe ischemia followed by heterogeneous hyperemia after the occlusion is released. The chapter presents the morphological observations that reveal that five minutes of forebrain ischemia in gerbils lead to highly reproducible delayed destruction of neurons in the hippocampal CA1 subfield. With respect to CAlN, notable changes are observed first at two days following ischemia, at the time neurons show some loss of Nissl substance, a more accentuated staining of dendrites, and appearance of clear clefts in the cytoplasm. After three days, most of the CAlN shows severe ischemic injury, followed by neuronal disintegration at four days. The cortex showed no pathological changes during the whole observation period. The described changes of various parameters resulting from five minutes ischemia in gerbils demonstrate that ischemic death of CAlN takes place during the recirculation period.

Peritumoral cerebral edema in meningiomas: the role of the tumor-brain interface

We investigated the role of the tumor-brain interface in the production of peritumoral cerebral edema in meningiomas by analysing the size, shape, histological type and location of the tumor, and radiological and operative findings. Our results suggest that changes of the boundary zone between the tumor and the brain such as the disappearance of the subarachnoid space, cortical thinning or loss, and possibly partial loss of the arachnoid membrane are the most important factors in edema production, and that multiple other factors determine the morphological changes which occur at the tumor-brain interface.

A review of 102 consecutive patients with intracranial aneurysms in a community hospital in Japan.

SummaryOne hundred and two consecutive non selected patients with intracranial aneurysms were reviewed. The incidence of ruptured aneurysm was 17.5 per population of 100,000 per year. The patients were divided into two groups, according to a change of policy that reversed the timing of operations from delayed to early surgery. The overall mortality and occurrence rate of neurological deficits due to vasospasm in patients in Hunt and Kosnik grades I through III were found to be lower during the period with a policy of early surgery. Elderly patients over 70 years old constituted 19% of the cases and those in poor condition (grade IV and V) 31%. These figures in this study are high, which may reflect the fact that these are common problems inherent in the treatment of ruptured aneurysms without patient selection at most community hospitals in the forefront of primary medical care.

Unruptured aneurysms in patients with transient ischemic attack or reversible ischemic neurological deficit

Thirty-five patients with unruptured aneurysms were treated between 1981 and 1987. Eight of them had either transient ischemic attacks or reversible ischemic neurological deficits as their presenting symptoms. Six of the eight patients underwent direct aneurysm surgery. All eight patients are well, and have had no recurrent attack during the follow-up period ranging from 2 to 7 years. The feasibility of surgical treatment for such aneurysms associated with reversible ischemic symptoms is discussed.