Effect of Focal Brain Retraction on the Regional Cerebral Blood Flow and the Electroencephalographic Activity in the Cat

The use of brain retractors, unavoidable method in operation of deep intracranial lesions, may lead to focal cerebral ischemia and thereby cause brain infarction. In such operation, the surgical microscope is commonly used to get good surgical field. However, as the time of operation becomes lengthened, it results in longer retraction of the brain and probable greater ischemic infarction. To estimate the risk of ischemic damage, the authors investigated the regional cerebral blood flow(rCBF) and the electroencephalographic(EEG) activity at different forces and durations of the brain retraction in the cat models simulating the frontal approach of the pituitary surgery. Twenty-six adult cats weighing from 2.4 to 4.5 kg were used in this study. The animals were divided into 3 groups : control(n=6), 20g-retraction(n=10), and 30g-retraction groups(n=10) respectively. The brain retraction was produced by applying the lead weight with the stainless steel retractor on the right frontal lobe through a craniectomy over the right frontal bone. The weight(20g or 30g) was supported with the pulley so that its long axis was perpendicular to the cortical surface, The measurements of rCBF activity were carried out in each animal before and immediately after brain retraction at 30 min, 60 min, 90 min, 120 min and 180 min after retraction. The results were as follows ; 1) After brain retraction, there were rise in intracranial pressure, bradycardia, elevation in blood pressure and alteration in respiration at 60 min after brain retraction. 2) Normal control flows(rCBF, ml/100g/min) were 39.7+/-6.1 in the right frontal, 37.8+/-2.6 in the left frontal, 37.5+/-3.6 in the right parietal and 38.8+/-4.1 in the left parietal lobes. 3) A considerable reduction in rCBF was demonstrated at 60 min after brain retraction. A reduction of rCBF to 40% of control flow(19.5+/-7.5ml/100g/min) was found at 60 min after retraction in the right frontal with the 20g-retractor. With the 30g-retractor, rCBF were reduced to 64% of control flow(13.3+/-6.8ml/100g/min) at 60 min and 90% of control flow(4.0+/-2.1 ml/100g/min) at 180 min after retraction in the right frontal lobe. 4) A close correlation was found between EEG activity and rCBF changes, suggesting a threshold relationship. The changes of EEG activity began to be noted at the rCBF value of less than 20.0 ml/100g/min. A 50% suppression of the EEG activity appeared at the rCBF value of 4.0+/-1.2 ml/100g/min. It is concluded that EEG activity is secondarily is secondarily suppressed by reduction in local blood flow which is caused by local compression. It is advisable to retract the brain with the least force necessary and for the shortest time possible. It is also suggested to resect the brain partially before retraction to avoid irreversible ischemic infarction of the brain in consequence of forceful, longtime retraction in exploration of deep intracranial lesions.

Controlled Evacuation of Spontaneous Intracranial Hematoma with CT-aided Stereotaxic Urokinase Therapy

Authors describe methods for evacuation of intracerebral and/or intraventricular hematomas with CT-aided stereotaxic infusion of urokinase into the hematoma and controlled drainage. In the past 6 months we performed the procedures in 21 cases during acute(within 3 days) or subacute(between 4 and 14 days) stage after the apoplectic attack. Three dimensional CT images were used to locate the hematoma sites, to assess its volume and to determine stereotaxic coordinates. Under local anesthesia a silicon tube was inserted into the hematoma through burr hole and the hematoma was aspirated with syringe. And then urokinase(6,000IU/5ml saline) was infused into the hematoma and the drain was clipped. There after aspiration and administration were performed repeatedly every 6 hours until the hematoma was completely removed. In cases of intraventricular hematoma a drain was inserted into the ventricle having the main hematoma. As a first trial of hematoma removal, the ventricle was irrigated with urokinase(6,000IU/100ml saline), and the drain was clipped after administration of urokinase(6,000IU/5ml saline). Subsequentry clipping of the drain for 4 hours and drainage of the CSF with the hematoma for 2 hours were repeated under the monitoring of intracranial pressure. Now we review serial changes of CT findings and results of 10 cases which were followed up for at least 4 months' and preliminarily conclude that this procedure may be as good as conventional cranitomy, and safer and less traumatic than any other management especially in cases of intraventricular or deep seated hematomas and elderly or high-risk patients.

A Case of Glioblastoma Multiforme of the Cerebellum

Most of glioblastoma multiforme in brain are known to be located supratentorially. On posterior fossa, they are mostly found in brain stem and cerebellar case is rare. A case of cerebellar glioblastoma multiforme is presented with the review of literatures.

A Case of Spontaneous Hematomyelia

This is a report of 23 year old soldier who developed sudden onset of flaccid paraplegia and loss of all sensory modalited below the level of T4. The clinical entities of hematomyelia were sudden onset of pain, repidly developing pyramidal signs and paraplegia. The mainly involving sites of this disease were cervical and thoracic regions. The causative factors were hemorrhagic diasthesis, vascular malformation and inflammatory process as well as trauma and neoplasms affecting the spinal cord. We experienced a case of hematomyelia which did not combine with vascular anomaly, inflammatory process, hemophilia or trauma history.

Hydrocephalus In Achondroplasia: Case Report

Major neurological features of achondroplasia are attributed to premature synostoses of the pedicles of the vertebrae and of the base of the skull producing obstruction of the ventricular fluid circulation or compression of the medulla and spinal cord. Significant hydrocephalus is due to the obstruction of the cerebrosspinal fluid pathways at the level of the foramen magnum or the disturbance of CSF absorption caused by increased superior sagittal sinus pressure. In generally, the hydrocephalus in achondroplasia is of the communicating type in the pattern, so the CSF diversionary shunt may not be indicate. But, shunting procedures may be needed in patients who showed signs of severe IICP such as bulging fontanels and enlarged lateral ventricle. In this case, we experienced that the hydrocephalus in achondroplasia is prosorption following the stenosis of the foramen magnum and increased superior sagittal sinus pressure.

A Case of Posterior Medullary Hemangioblastoma

The source of hemangioblastoma in the hindbrain was considered to be avascular analoge in or adjacent to the posterior medullary velum. In hemangioblastoma of the brain stem, the area postrema has been known as the most common site. Operative and autopsy findings were confirmed by Okawara that the solid lesions are more likely to involve the brain stem. The solid hemangioblastoma is much more difficult to treat and the mortality is higher than the cystic type due to involvement of the brain stem, massive postoperative edema, and intraoperative or postoperative bleeding from the tumor mass. Operative and histopathologic findings of our case are confirmed with solid hemangioblastoma which involves the posterior medullary oblongata and was regarded as arising at the postrema.

C-T Finding in Behcet's Disease (Case Report)

The clinical triad of Behcet's Disease is relapsing iritis and ulcers of the mouth and genitalia. The diagnosis of Behcet's Disease is based only on clinical grounds, as there are no pathognomic or histologic features. A reported case of Behcet's Disease with neurologic manifestations that have undergone computerized tomography of the brain have demonstrated lesion of decreased density with negative contrast enhancement in basal ganglia which is similar with the other reported cases.

A Case of Arachnoid Cyst in the Middle Cranial Fossa

The authors report a case of arachnoid cyst arisen in the middle cranial fossa combined with intracystic hemorrhage. The pre-operative diagnosis was confused with chronic subdural hematoma. The post-operative final pathologic diagnosis was arachnoid cyst. The plain skull and C-T findings are illustrated. The light microscopic features of arachnoid cyst are presented. The brief description of the treatment and its prognosis are given.