Cerebral Infarction Size According to the Duration of the Middle Cerebral Artery Occlusion in the Reversible and Irreversible Ischemic Infarction Models in the Rat

To establish a simple recirculation model in rats without craniectomy and to determine the recirculation time necessary to benefits the infarction area with restoration of the blood flow in a series of 30 adult rats, the authors induced irreversible ischemia(group I) in 15 rats through unilateral occlusion of the middle cerebral artery(MCA) by inserting a 16mm length of 4-0 nylon surgical thread through the internal carotid carotid artery(ICA). Reversible ischemia(group II) was induced by pullin the thread that occluded the MCA with hours recirculation in 5 rats. The author again divided the rats into 4 hours(Ia and Iia), 6 hours(Ib and Iib) and 12 hours(Ic and Iic) groups designated as according to the sacrifice time of rats in group I and the starting time of recirculation in group II following the MCA occlusion. The percentage of the infarction area to the total brain was calculated by a computer image analysis system, and the infarction size between reversible and irreversible groups were compared. The results showed that although the total average infarction sizes of irreversible ischemic groups were larger than those of reversible ischemic groups, the difference of the infarction size between each group o irreversible and reversible ischemia was not significant(group Ia Vs. Iia:7.78+/-8.37% Vs. 3.28+/-1.98%; group Ib Vs. Iib: 9.07+/-4.72% Vs. 6.61+/-3.19;group Ic Vs. Iic: 8.35+/-4.47% Vs. 6.90+/-6.07%. p>0.05, one-way ANOVA test). However, the degree of difference of the infarction size between irreversible and reversible ischemia decrease along with the prolongation of ischemic duration(difference between group Ia and IIa:4.5%;group Ib and Iib:2.46%;group Ic and Iic:.45%. The author concludes that ischemic brain injury may be decreased by making a restoration of the blood flow within 4 hours after occlusion of a blood vessel in rats, and this kind of reversible ischemic model may be useful in various studies on the focal cerebral ischemia without manipulation of the brain tissue and blood vessel.

Surgery of Intractable Epilepsy with Calcified Mass Lesions in the Temporal Lobe

We present 10 patients who underwent temporal lobe surgery for seizure control on our institution between December, 1992 and October, 1994. Preoperative neuroimaging studies of all 10 patients showed calcified mass lesions within the temporal lobe. Among them, 5 cases had mesial temporal calcified mass close to the hippocampus, 3 diffuse mass in the temporal lobe or multilobes and 2 in the temporal tip. All patients presented with complex partial seizure and seven had secondary generalization from their seizures. The duration of epileptic seizure varied between 4 and 23 years(mean 13 year). The patients were refractory to therapeutic levels of anticonvulsant medication. Presurgical evaluations of epilepsy included a detailed clinical history, multiple scalp/shenoidal EEG, prolonged Video-EEG monitoring, neuroimaging, neuropsychological test, WADA test and invasive study with subdural strip electrodes. Anterior temporal lobectomy with lesionectomy were performed in six cases and anterior temporal lobectomy in four cases using intraoperative electrocorticography(EcoG) and/or functional mapping under local or general anesthesia. The extent of resection of amygdala and hippocampus were determined according to electrocorticographic findings. The verified histopathology of the calcified lesions revealed 1 oligodendroglioma, 1 mixed glioma, 1 arterioveous malformation, 1 paragonimiasis, 2 neurocysticercosis, 1 other parasitic granuloma and 3 calcified fibrous nodule. In four patients, severe hippocampal sclerosis with neuronal cell loss and gliosis were observed. After a mean postoperative follow-up of 9 months, 9 patients showed a seizure-free outcome and one patient a significant reduction in seizure activity. We conclude from our studies that temporal lobe surgery for patients refractory to therapeutic levels of long-term anticonvulsant medication can result in excellent postoperative seizure-free outcome in the majority of the patients, and that brain tumors, vascular malformations, and parasitic infections may be considered as etiologic factors of calcified mass lesions in the temporal lobe of such patients.

Visual Loss Related to Papilledema:Report of 5 Cases

Five cases of complete visual loss related to papilledema were presented. The diagnoses of cases were an intracranial arachnoid cyst(1 case), brain tumors(3 cases) and benign intracranial hypertension(BIICP) followed by a minor head trauma(1 case). All cases had marked papilledema at admission and their range of age was from 4 to 27 years. The timings of visual loss were preadmission in 2 cases, during admission following removal of posterior fossa tumor(1 case) and revision of cysto-peritioneal shunt in a case of an arachnoid cyst(1 case), and during follow-up after conservative management of a minor head trauma(BIICP) in 1. Their visual function had not improved during the follow-up from 3 months to 9 years. Optic nerve sheath decompression should be considered in the case of BIICP for improving the vision. In cases who have well developed chronic papilledema, visual loss that is abrupt may be followed by cranial decompression. We stress neurosurgeons should predict a tragic outcome of visual loss during the management of cases who have well developed chronic papilledema, especially in children and young adult patients.

Result of Surgical Management of Pituitary Tumor

The authors report results of surgical management in seventy-four cases of pituitary tumor who were treated in the department of neurosurgery, Keimyung University from Jan. 1987 to Dec. 1992. The composition of cases are prolactinoma in twenty-six cases, growth hormone(GH) secreting tumor in twenty, adrenocorticotropic hormone(ACTH) secreting tumor in three, thyrotropic hormone(TSH) secreting tumor in one and nonsecreting tumor in twenty-four cases. Fourty cases(54.1%) showed suprasellar and/or parasellar extension in the radiological studies. The modialites of management were surgery only in fourty-seven cases and surgery with radiation therapy in twenty-seven cases. Bromocriptin was medicated in twenty-two cases postoperatively. The management results in cases of prolactinoma, thirteen(50.0%) cases were cured and eight(30.8%) cases were improved. In the cases of GH secreting tumor, ten(50%) cases were cured and five(25%) cases were improved. Among three cases of ACTH secreting tumor, two cases were cured and there was one case of TSH secreting tumor which was cured. The worst management result were noticed in the cases of GH secreting tumor which extended suprasellar and/or parasellar region. of the thirty-five cases who had preoperative visual impairment(twenty-one cases of functional tumor and fourteen cases of nonfunctional tumor), twenty-seven(77.1%) cases were improved, sex(17.1%) cases not improved and two(5.7%) cases aggravated. The common complications after surgical management were hypopituitarism(eleven cases) and transient diabetes insipidus(nine cases). Recurrence was noticed in one case during follow-up period and three cases were expired, wtih one case during perioperative period and two during follow-up period. We conclude that an extensive effort should be made to diagnose early and advance surgical technique so as to improve the results of surgical management of the pituitary tumor.

The Evaluation and Quantification of Cerebral Infarction Following a Middle Cerebral Artery Occlusion in Rats

In order to find out the accuracy of the quantification of the infarction area by using triphenyltetrazolium chloride(TTC) staining and to evaluate the change of the infarction size according to the duration after the ischemic insult, in a series of 33 adult rats, a surgical occlusion of the middle cerebral artery(MCA) was carried out through a small subtemporal craniotomy. 11 animals at 6 hour, 12 animals at 24 hour and 10 animals at 48 hour following the surgical occlusion of the MCA, rats were sacrificed and brain slices were obtained and stained with TTC, and hematoxyline and eosin(H & E). The size of the infraction area stained by each method was quantified by a computer image analysis system. The average percent of the infarction size(+/-standard error) was larger in the 24 and 48 hour groups than that of the 6 hour group(determined by TTC:9.94+/-0.97 vs. 9.98+/-1.08 vs. 6.83+/-0.82%, respectively:6 hour vs. 24 & 48 hour groups;one-way ANOVA test p0.05), and linear regression analysis showed a significant correlation existed between the two methods in all groups. However, the degree of correlation was more prominent in the 24 and the 48 hour groups than 6 hour group(6 hour group:r=0.76, slope=0.78, y intercept=0.55;24 hour group:r=0.97, slope=1.03, y intercept=-0.78;48 hour group:r=0.98, slope=0.94, y intercept=0.42). From this study it is concluded that: 1) the evolution of the infarction size continues up to 24 hours following the arterial occlusion, and thereafter, the change of the infarction size is minimal in the rat. This data suggests that it is sufficient to evaluate the change of the infarction size up to 24 hours following the ischemic insult in the experimental study of ischemia in the rat. 2) the detection and the quantification of the cerebral infarction by using TTC staining is a reliable method after 24 hours following the ischemic insult. However, in the earlier period than 24 hours following the ischemic insult, staining with TTC coupled with histopathological H & E staining will add to the accuracy in the obtainin the quantity of the cerebral infarction in the rat.