Biomedical subjects
Publications and source records attributed to K Mizoi.
A case of enterogenous cyst at the cerebellopontine (CP) angle is reported. A review of the literature yielded only seven cases of intracranial enterogenous cysts, and our case is the first one arising at the CP angle. The histological features, pathogenesis, and radiological and auditory brain stem response findings are discussed.
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Ten cases of surgically treated brain stem cavernous angiomas are reported in this paper, and their clinical and radiological features are reported. There were 9 males and 1 female with ages ranging from 9 to 69 years (average 36 years). Four of the cavernous angiomas were located in the dorsal pons, two in the middle cerebellar peduncle, two in the hypothalamus, and one each in the cerebral peduncle and the superior colliculus. All the ten patients came to medical attention because of the sudden onset of neurological abnormalities following brain stem hemorrhage. Six of the 10 patients showed neurological deterioration due to rebleeding at various intervals ranging from 10 days to 2 years. After intravenous injection of iodinated contrast materials, negative contrast enhancement was commonly seen. In a few cases, there was faint enhancement of the nodule at the periphery of the hematoma. Serial computed tomography (CT) scans over a period revealed an unchanged hyperdense mass lesion, which was thought to be a most characteristic and indicative CT feature of the cavernous angioma. On magnetic resonance imaging (MRI), the combination of a mixed signal intensity with a surrounding rim of decreased signal intensity (hemosiderin rim) suggested the presence of a cavernous angioma. Enhanced MRI, using gadopentate dimeglumine, was thought to be more sensitive than contrast enhanced CT in detecting cavernous angiomas. All these cases underwent surgery with good results. Abnormal vascular tissue in the wall of the hematoma cavity was recognized at operation and pathological confirmation was obtained in all cases. These data indicate that brain stem cavernous angiomas can be surgically removed with acceptable morbidity.
This study reviews aneurysms of the proximal segment (A1) of the anterior cerebral artery in 38 patients (23 men and 15 women) and their surgical, angiographic, and clinical management. Thirty-seven aneurysms were saccular and one was fusiform. The incidence of A1 aneurysms among a total of 4295 aneurysm cases treated was 0.88%. Multiple aneurysms occurred in 17 patients (44.7%) of the 38 cases; in 10 (58.8%), there was bleeding from the A1 aneurysm. The aneurysms were classified into five categories according to the mode of origin of the aneurysm in relation to the A1 segment: in 21 cases, aneurysms originated from the junction of the A1 segment and a perforating artery; in eight, from the A1 segment directly; in six, from the proximal end of the A1 fenestration; and in two, from the junction of the A1 segment and the cortical branch. One patient had a fusiform aneurysm. Computerized tomography (CT) of these aneurysms revealed bleeding extending to the septum pellucidum similar to that of anterior communicating artery aneurysms. When performing radical surgery it is very important to recognize the characteristics of A1 aneurysms, including multiplicity, a high incidence of vascular anomalies (especially A1 fenestration), and their similarity to anterior communicating artery aneurysms on CT.
The authors present two cases of giant cerebellar hemispheric arteriovenous malformation (AVM) managed with staged preoperative embolization and surgical resection. A new embolization technique is described, combining injection of estrogen alcohol and polyvinyl acetate into AVM's by superselective catheterization of feeding arteries. Polyvinyl acetate proved to be an ideal liquid embolic material; because it polymerizes quickly and remains in a gelatinous state after injection, there was no difficulty in cutting and retracting the obliterated AVM during surgery. Intraoperative digital subtraction angiography was useful for confirming complete excision of the large and complex AVM.
The effectiveness of acute stage vascular reconstruction in cases of progressing stroke is reported. The clinical material consists of 28 cases of progressing stroke in the anterior circulation upon which vascular reconstruction was performed. Following admission, brain protective substances (500 ml mannitol, 500 mg vitamin E, 500 mg phenytoin) and dextran, were administered to the patients, and induced hypertension was also performed. Changes in symptoms were then observed and vascular reconstruction was carried out in cases where symptoms progressed. The vascular lesion was on the internal carotid artery in 8 cases and on the middle cerebral artery in 20 cases. Complete disappearance of neurological symptoms was obtained in 12 cases, whereas only mild neurological symptoms remained but a return to normal social life was possible in 11 other cases. Symptoms remained in three cases and there were two fatalities. In a long-term follow-up study, there were no cases of aggravation of symptoms due to ischaemic stroke. Moreover, the reconstruction was judged as effective on the basis of cerebral blood flow and metabolism. We concluded that acute vascular reconstruction for progressing stroke under the administration of brain protective substances is effective in preventing the progression of neurological symptoms.
In this study, we evaluated the efficacy of postoperative intrathecal injections of tissue-type plasminogen activator (tPA) in preventing cerebral vasospasm in cases with a diffuse severe subarachnoid hemorrhage. All 10 cases were graded Group 3 according to the classification of Fisher and associates, and the CT number (Hounsfield number) of the subarachnoid clot was over 75. After clipping the aneurysm and removing the clot, three cisternal drainage catheters were inserted into both sylvian cisterns and the prepontine cistern, and continuous ventricular drainage was performed routinely. Postoperatively, tPA (0.5 mg/2.5 ml) was infused as a bolus into both basal cisterns and the lateral ventricle twice daily for about 6 days. Angiography and cerebral blood flow studies using single photon emission computed tomography were performed on Day 4 or 5 and between Days 7 and 10 after onset of the hemorrhage. To date, there have been no cases that have shown angiographic vasospasm or delayed ischemic neurological deficits. This preliminary study indicates that the intrathecal bolus injection of tPA produces a marked effect on vasospasm.
Somatosensory evoked potentials (SEPs) and cerebral blood flow (CBF) were monitored during temporary vascular occlusion in 67 aneurysm operations to evaluate the usefulness of SEP as an indicator for cerebral ischemia. The SEP N20 component completely disappeared during temporary vascular occlusion in 24 cases, 23 of which demonstrated complete recovery following recirculation and had no postoperative neurological sequelae. The only one with postoperative sequelae demonstrated rapid, within 1 minute, loss of N20 followed by no recovery. Another eight cases showed prolongation of central conduction time during vascular occlusion and had no postoperative sequelae. The SEP N20 attenuation reflected the CBF reduction in the middle cerebral artery (MCA) territory during MCA occlusion. However, CBF changes in the internal carotid artery (ICA) territory during ICA occlusion greatly varied. No detectable changes in SEP were found during anterior cerebral artery occlusion for anterior communicating artery aneurysms. This study indicates that intraoperative SEP monitoring is useful to detect ischemia in the MCA territory and that rapid disappearance of the N20 component is a danger signal.
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A rare case of the dural AVM mainly around the left petrosal sinus was reported. A 64 years old man was admitted just after the sudden onset of severe headache and nausea. The CT scan revealed subarachnoid hemorrhage in the left ambient cisterns. A small hematoma was also found in the left cerebellar peduncle. External carotid angiogram showed a dural AVM which nidus was located adjacent to the left superior petrosal sinus. Its feeding arteries were as follows; the middle meningeal artery, the artery of foramen rotundum, the accessory meningeal artery, the dural branch of occipital artery and the ascending pharyngeal artery. The voluminous petrosal vein and the dilated cortical veins were identified as drainers and, the portion of the latter appeared as "varix" embedded in the pons, which was clearly delineated by MRI. In the venous phase, stenotic straight sinus and residual Falcine sinus were illustrated. Superselective embolization of the feeding arteries was employed followed by the direct clippings of draining vein. Postoperative course was uneventful. The present case should be classified into the tentorial dural AVM. Only 26 cases of this rarely encountered entity was reported in the literature. Based on both the present and the previously reported cases, the clinical features, treatment and pathogenesis of this disease were briefly discussed.
Aortic regurgitation (AR) has been studied experimentally, however these reports did not investigate compensatory mechanisms in AR in relation with the severity of regurgitation. If the severity of AR can be changed voluntarily, we can evaluate the pathophysiological response to AR in wide range. The purposes of this study were 1) to see if the extent of fall in aortic diastolic pressure immediately after the production of AR (delta AoDP) was a reliable predictor of the severity of AR and 2) to evaluate the process of adaptation through acute and chronic stage in moderate AR in the rabbit model. AR was produced by perforating the aortic valves in Japanese white rabbits. First, aortic pressure, volume, weight and wall thickness of the left ventricle were measured. Correlations between delta AoDP and body weight-corrected volume (LVV/BW) and weight (LVW/BW) were studied in 18 rabbits soon after, 19 one week after, 23 four weeks after and 10 eight weeks after the production of AR. delta AoDP was closely correlated with LVV/BW after 1 week (1 week: R = 0.667, p less than 0.01, 4 weeks: R = 0.733, p less than 0.01, 8 weeks: R = 0.757, p less than 0.05) and with LVW/BW after 4 weeks (4 weeks: R = 0.484, p less than 0.05, 8 weeks: R = 0.651, p less than 0.05). The slope of these regression equations increased with time (delta AoDP and LVV/BW: 1 week: 0.0138, 4 weeks: 0.0361, 8 weeks: 0.0577 ml/kg.mmHg; delta AoDP and LVW/BW; 4 weeks: 0.0142 8 weeks: 0.0310 g/kg.mmHg).(ABSTRACT TRUNCATED AT 250 WORDS)
We report two cases of asymptomatic occlusion of the main trunk of the cerebral artery associated with subcortical hemorrhage in the area fed by collateral circulation. The first patient, a 51-year-old female who had suffered from untreated hypertension for 20 years, was hospitalized in a state of coma. Computed tomography (CT) revealed a subcortical hemorrhage in the right parietal lobe as well as subdural and subarachnoid hemorrhages. Cerebral angiography disclosed occlusion of the right internal carotid artery at its origin. The region normally supplied by the right anterior (ACA) and middle cerebral (MCA) arteries was supplied instead by the posterior cerebral artery via leptomeningeal anastomosis. The hematoma was removed and the patient was discharged 1 month later. The second patient was a 54-year-old female who had suffered from uncontrollable hypertension for 27 years and was hospitalized after sudden development of stupor, right hemiparesis and motor aphasia. CT demonstrated a subcortical hemorrhage in the left parietal lobe. Cerebral angiography disclosed occlusion of the left MCA at its origin. The area normally fed by the left MCA was supplied instead by the ACA by way of leptomeningeal anastomosis. One month after operation the patient was transferred to another hospital for rehabilitation of right hemiparesis. Both of these middle-aged women had long-standing hypertension. The hemorrhages were thought to result from rupture of the leptomeningeal anastomosis, which had developed as collateral vessels. It is probable that the relatively weak leptomeningeal anastomosis could no longer withstand the increased blood flow brought on by the hypertension.
A study was made of the protective effects of several drugs (mannitol, phenytoin, vitamin E and dexamethasone) on the electrical activities of guinea pig hippocampal neurons in vitro when they were treated with a bathing medium deprived of both oxygen and glucose. Using guinea pig hippocampal slices, antidromic field potentials in the granular cell layer of the dentate gyrus were recorded stimulating mossy fibers. A model of ischemia in vivo in the slices was achieved by removing both oxygen and glucose from the perfusing medium. In standard medium, after 10 min of both oxygen and glucose deprivation, the field potentials exhibited minimum recovery with an amplitude of 6% of the control after 60 min. The protective effect of the drugs was evaluated by recovery of the field potential amplitude of the 60 min post-deprivation response and histological examination of the brain slice tissue. Drugs were added during 30 min of pre-deprivation and during deprivation. In this experiment we demonstrated that (1) phenytoin and vitamin E clearly showed protective action against neuronal damage caused by both oxygen and glucose deprivation in guinea pig hippocampal slices, (2) combined application of these drugs was more effective, and (3) mannitol showed no protective action in vitro. It was also demonstrated that (4) the dentate antidromic field response can be a useful index of cell death.
We review the surgical results in 372 cases of multiple intracranial aneurysms over a 25-year period in which one of us (JS) performed 2,000 direct operations for aneurysms. All patients were classified into four groups according to the location of the aneurysm: Group 1: multiple aneurysms including anterior communicating artery aneurysm (157 cases); Group 2: multiple aneurysms of unilateral anterior circulation (72 cases); Group 3: multiple aneurysms of bilateral anterior circulation (110 cases); Group 4: multiple aneurysms including vertebro-basilar artery aneurysms (33 cases). In multiple aneurysm cases, our policy has been to treat all aneurysms, ruptured and unruptured, in a one-stage operation whenever possible. About 90% of patients in both Group 1 and 2 were treated by one-stage operations, while 60% of patients in Group 3 and 42% of patients in Group 4 were operated on in the same manner. Excellent and good results in from 73% to 81% of cases were obtained in patients in Group 1, Group 2 and Group 3. Morbidity was 14-19% and mortality was 6-8%. These results were comparable to the results with a single aneurysm of the anterior circulation. On the other hand, the surgical results in Group 4 were poor with a mortality of 27%. Poor results were attributable to the postoperative rebleeding from the untreated vertebro-basilar aneurysms, which were thought to be unruptured aneurysms preoperatively. Furthermore, it was clarified that the results of early one-stage operations (within one week from onset) in patients with multiple aneurysms were satisfactory. In this group, there was good recovery in 84% of patients, 7% were disabled and 9% died.(ABSTRACT TRUNCATED AT 250 WORDS)
A 46-year-old female was transported to our clinic 4 hours after the onset of sudden headache and transient loss of consciousness. On admission, she was drowsy with slight left hemiparesis and anisocoria (left greater than right). The CT scan revealed a right subdural neurological deficit one month after the operation. the operation, we found that the hematoma was derived from a small meningioma attached to the dura at the middle temporal fossa. The meningioma was 1.5 cm in diameter. The patient was discharged without neurological deficit one month after the operation. Although glioblastoma and metastatic brain tumor are most common, meningioma is rare as a cause of intracranial bleeding. Among 69 cases of meningioma with intracranial bleeding reported previously, only 4 cases were accompanied with acute subdural hematoma.
A case of surgically treated intramedullary spinal cavity which appeared 1 year after a minor injury was presented. A 15 year-old boy developed nuchalgia and muscle weakness of his right arm and leg. On admission, he had right hemiparesis and sensory disturbances in the right C6-C8 and left T1-S5 dermatomes. Metrizamide-CT scan and MRI disclosed an intramedullary spinal cavity between C4-C5 vertebral levels. A myelotomy and a biopsy of the cavity wall were carried out in order to communicate the cavity with the subarachnoid space, and to make a definite diagnosis. The microscopic examination of a biopsy specimen revealed no tumor findings but inflammation. Taking into account the location of the cavity, a site corresponding with the site of a previous trauma, the authors finally diagnosed the cavity as intramedullary spinal cavitation after minor trauma. His symptoms improved remarkably after the operation.
The authors report their experience with the surgical treatment of carotid-ophthalmic aneurysms in 29 cases, and describe their surgical technique. The technique can be summarized as follows. When dissecting the aneurysm, temporary vascular occlusion of the common carotid artery and external carotid artery is done in the neck under the administration of cerebral protective substances. Through a bifrontal craniotomy, wide dissection of the Sylvian fissures and the interhemispheric fissure is performed. When necessary, the anterior clinoid process and the roof of the optic canal are removed. This approach allows for observation of the neck of the aneurysm from various angles, thus facilitating clipping of the neck. There have been no previous reports of direct surgery on carotid-ophthalmic aneurysms using an interhemispheric approach, but this approach provides a much larger operative field and a better exposure of the aneurysm than other surgical approaches.
To test the effect of flunarizine on cerebral ischaemia, 15 dogs were subjected to ischaemia, using the 'canine model of the completely ischaemic brain regulated with a perfusion method' in which the cerebral blood flow (CBF) can be fully regulated. Five animals served as untreated controls, 10 received flunarizine, a calcium antagonist (1 mg/kg in 5 dogs and 3 mg/kg in 5 dogs), before the ischaemic period. After 1 h CBF was restored and recovery of the electrical activity of the brain and the degree of brain swelling were observed for 3 h. At the end of the experiments, the degree of extravasation of Evans blue was examined. Remarkable recovery of EEG was found in the groups given flunarizine when compared with untreated controls. However, no significant difference was found between untreated controls and flunarizine treated groups for the degree of brain swelling and the degree of extravasation of Evans blue. These results suggest that the treatment of flunarizine is of benefit for functional recovery against cerebral ischaemia, but does not suppress ischaemic brain oedema.