Regional Cerebral Blood Flow on Cerebral Reperfusion after Occlusion of Bilateral Common Carotid Arteries : An Experimental Cat Model

The microvasculature of the brain is also quite susceptible to ischemic insult, and substantial portions of the brain are not reperfused after restoration of the blood supply following overtime of critical ischemic periods. The purpose of this series of experiments was to determine the effects of ischemia on subsequential regional cerebral blood flow measurements and cortical electric activities following reperfusion after ischemia and also to define the proper time of vascular occlusion without irreversible neural damage. Cerebral ischemia was induced in cat by bilateral common carotid occlusions for periods of 10, 30, to 60 minutes, and the blood flow(rCBF) was measured by hydrogen clearance technique following ischemia, restoration of blood supply and electroencephalogram recovery could be predicted according to the rCBF. Forty adult cats weighing 2.7 to 4.0kg were used in this study. The animals were divided into 4 groups of 10 cats each : normal control, 10 min-clamped, 30 min-clamped, and 60 min-clamped groups. The results obtained were as follows : 1) The mean rCBF was 24.6+/-7.0ml/100g/min in control group. 2) Bilateral carotid occlusions resulted in a reduction of the rCBF (12.4+/-4.1ml/100g/min) to 50% of control flow on both hemispheres. 3) Sequential changes of the rCBF after reperfusion. (1) There was restored the rCBF(21.3+/-5.1ml/100g/min) to control flow in the 10 minutes-clamped group. (2) There was a 85% recovery of control flow in the 30 minutes-clamped group. (3) There was a only 25% recovery of control flow in the 60 minutes-clamped group. 4) A close correlation was found between cortical electrical activity and rCBF suggesting a threshold relationship. (1) The changes of cortical electric activity began to notice at rCBF less than 17.4+/-4.7ml/100g/min. (2) The changes of cortical electric activity noted at rCBF more than 10.2+/-2.3ml/100g/min. 5) There was no evidence of ischemic involvement at the cortex, white matter and basal ganglia in the 10 minutes clamped group, but demonstrated a dense wedge shaped infarct at the cortex and uncus herniation in the 60 minutes clamped group. The rCBF and cortical electric activity restorted to normal values in reperfusion within 10 minutes after occlusion of both common carotid arteries.

The Value of Computerized Tomography in Head Injury Patients with No Neurological Deficits

Computerized tomography(CT) has proven to be far superior to other diagnostic studies in the detection of intracranial lesions after head injuries. The procedure is especially appropriate for early and accurate diagnosis because it can be done quickly with no discomfort and minimal risk. CT was utilized as a screening diagnostic procedures in 100 consecutive patients of head injuries who were alert and neurologically no deficits in a 8 months period. 11 abnormal CT Scans found at 10 patients:six epidural hematomas, two intracerebral hematomas, one sudural hygroma and one temporal contusion. The cases presented are discussed in light of pertinent literature.

Effects of the Rheomacrodex and Alteration of Blood Pressure after Experimental Occlusion of the Middle Cerebral Artery

An experiment was planned to observe the histopathological alteration with administration of the Rheomacrodex and blood pressure changes in induced cerebral infarct after occlusion. Eighty well developed cats, weighing 2.3 to 3.5kg, were used in this experiment. The right MCA was exposed through temporal approach and the proximal part of the MCA was occluded with a silver clip. The animals were divided into 4 groups: The control group was comprised of 20 cats with occlusion of the right MCA alone, Rheomacrodex-treated group was comprised of 20 cats after occlusion of right MCA, induced hypotension and hypertension groups consisted in each 20 cats following occlusion of the MCA. The animals were sacrificed at intervals of 3 hours, 6 hours, 24 hours, 1 week and 2 weeks respectively after occlusion of the MCA. The animals were studied for clinical deficits and histopathological changes of the cerebral infarct according to the time courses. The results obtained were as follows: 1) In the control group, severe contralateral hemiplegia was developed in the early stage following the MCA occlusion, however the neurological deficits were progressively improved to the state of abnormal walking in 24 hours to 2 weeks. The hemorrhagic infarct was involving the basal ganglia, internal capsule and extending to the cortex with mild brain edema in the early stage and the area of the infarct was gradually enlarged from 6 hours to 24 hours following the MCA occlusion. Although the brain edema of surrounding area of the lesion was remained unchanged, the size and distribution of the infarct were decreased in one week to 2 weeks. Extensive ischemic neuronal damage was observed in the control group. 2) In the Rheomacrodex-treated group, mild to moderate neurological deficit was developed in the early stage after MCA occlusion and the deficit was less severe than control group. The clinical deficit was improving in the time course and one case had shown completely normal activity in 2 weeks. The distribution of the infarct was well defined and it was smaller than control group. The infarct mainly involved the basal ganglia and internal capsule. The area of the infarct was gradually enlarged from 6 hours to one week after MCA occlusion, then the extent of the infarct was decreased in 2 weeks. The ischemic neuronal change in this group was less severe than control group. 3) In the induced hypotension group, the early neurological deficit was worse than that of the control group and severe hemiplegia was developed in one week. There was minimal improvement of the neurological deficit in 2 weeks. The area of the infarct was ill-defined and hemorrhagic extending a large portion of the brain with severe brain edema. The infart was involving the basal ganglia, internal capsule, claustrum and the cortex from 3 hours to 24 hours after the occlusion and the area of the infarct was not changed during the observation. Severe ischemic nerve cell change or resolution of the cells was oserved in this group. 4) In the induced hypertension group, the neurological deficit was mild and it was better than that of the control group. The distribution of the infarct was well localized and minimum in extent. The extent of the infarct was not changed during the observation. There was no observable gross brain edema and the ischemic nerve cell changes were not severe.

A Case of Dandy Walker Cyst Variant

The "Dandy-Walker syndrome" has been the source of much controversy not only as to its embryogenesis but also concerning the correct diagnosis and surgical management of this disorder. The original description by Dandy and Blackfan emphasized the association of hydrocephalus, posterior fossa cyst and maldevelopment of the cerebellar vermis and later, Taggart and Walker described the genesis of these anomalities to atresia of the foramina of Magendie and Luschka. The Neuroradiologic findings associated with the presence of a Dandy-Walker cyst are pathognomonic. These findings relating to the cystic dilatation of the fourth ventricle which accompanies atresia and its outlets, gave a detailed clinicoanatomical information about the hydrocephalus in the CT scan. The CT scan contributed to the new advanced fields in the diagnosis and surgical management of hydrocephalus combining with the posterior fossa, lesion, because it was easily able to detect the lesion site stereoscopically and also find out the relationship to the involved surrounding area comparing with each of the slice in the CT scan. The purpose of this paper is to attempt to clarify the differentiation of the Dandy-Walker cyst variant from the Dancy-Walker cyst and anatomically detect the damaged brain correlated with the ventricular dilatation on the CT scan. A 7 year-old boy was admitted to the Department of Neurosurgery, Catholic Medical Center on Dec, 22, 1977 with one month history of progressive headache, nausea, vomiting and gait disturbance. On his examination he showed moderate enlargement of head, papilledema, diplopia, horizontal nystagmus, and gait disturbance. We confirmed the diagnosis under the Dandy Walker Cyst Variant by conray ventriclography and CT scan. He underwent lateral ventriculo-peritoneal shunt and then his symptoms progressively improved. He was discharged to his home after the 14th day of hospitalization.

An Analysis of the Result of Surgical Treatment of Anterior Communicating Aneurysms

The authors attempted to analyse the factors influencing the mortality involved in aneurysm surgery based on 38 cases of intracranial surgery for anterior communicating aneurysms, and obtained the following conclusion. 1. The surgical results are much better when the aneurysm surgery is delayed over one week after the occurrence of aneurysmal rupture, if there is no evidence of intracerebral hematoma. Administration of a massive dosage of epsilon aminocaproic acid in the waiting period prior to aneurysm surgery seems to be effective for preventing recurrence of bleeding from the aneurysm. 2. The direction of the anterior communicating aneurysm should be clearly visualized on a cerebral angiogram so that the most effective aneurysmal approach can be selected in surgery. 3. Microsurgery and hypotension in aneurysm surgery minimize brain damage in the exposure of aneurysm and provide accurate isolation of the aneurismal neck from the parent vessel in aneurysmal neck ligation. 4. Proximal ligation of the anterior cerebral artery is also an effective procedure to prevent recurrent hemorrhage from anterior communicating aneurysm.

Treatment of Cerebral Aneurysms and Aneurysm Surgery under Hypotension

Authors have experienced 104 cases of the intracranial aneurysms with subarachnoid hemorrhage, who were proved to have aneurysms by cerebral angiography for past 8 years. Aneurysms surgery under controlled hypotension has shown far better result than that of surgery under hypothermia, carotid ligation or conservative treatment. Of the 104 cases, the site distribution of aneurysms and the result of various treatment are analyzed. Followings are the results. 1. Anterior communication aneurysm was 44 per cent of the cases and it was most common site of the intracranial aneurysms. 19 per cent of aneurysms located on internal carotid artery at the posterior communicating artery, and middle cerebral artery aneurysm was 16%. The site distribution of aneurysms in Korean has shown marked difference from the reports of other countries. 2. Of 40 cases, who received conservative therapy, 15 cases (375% ) were expired, and most of them were dead due to rebleeding from aneurysms. 3. The direct attack of aneurysms through intracranial approach was performed under moderate hypothermia till 1970, and controlled hypotension was introduced thereafter. In 19 cases of intracranial aneurysm surgery, 7(14.2%) were expired following surgery. 4. Mortality of the carotid ligation for 15 cases of the intracranial aneurysms was 40 per cent. Cerebral ischemia or rebleeding was cause of death. 5. Intracranial aneurysm surgery under hypotension was carried out in 16 cases, and one cases (6.2%) was expired. Induced hypotension and careful identification of aneurysm and neighbouring structures by magnify operating glasses promoted operative result in aneurysm surgery.