The effect of transient bilateral carotid occulsion on levels of free fatty acids, phospholipids, and lipid peroxides in the brain was studied in gerbils. During occulsion, both saturated and polyunsaturated free fatty acids increased strikingly to approximately 11-fold in total by 30 minutes. During recirculation, however, a selectively rapid decrement occurred in arachidonic acid, while saturated fatty acids gradually decreased to their basal levels in 180 minutes. The peroxide level, estimated by a thiobarbituric acid test, did not change during occlusion, but was elevated on reperfusion. Phosphatidylethanolamine content decreased throughout the periods examined. These results do not support a hypothesis that lipid peroxidation is initated during ischemia by the lack of oxygen at the terminus of the mitochondrial respiratory chain. Instead, it is suggested that severe cerebral ischemia disintegrates membrane phospholipids, probably through activation of hydrolytic enzymes, and that overt peroxidative processes take place during reflow by means of restoration of oxygen supply. The peroxidative reactions may indeed, cause additional damage during the postischemic phase.

The authors conducted a prospective comparative study on the recurrence rate of chronic subdural hematoma after the use of two different treatment modalities: burr-hole irrigation of the hematoma cavity with (Group A) and without closed-system drainage (Group B). Thirty-eight patients were studied. Patients were assigned to groups sequentially upon admission. There were no significant differences between the two groups for age, sex, preoperative hematoma volume, and density on computed tomographic scan. One patient in Group A (5%) suffered a recurrence as opposed to 6 in Group B (33%). The difference in recurrence rate between the two groups was statistically significant (p < 0.05). The authors conclude that closed-system drainage after burr-hole irrigation reduces the recurrence rate of chronic subdural hematoma.

Brain free fatty acids (FFAs) and brain water content were measured in gerbils subjected to transient, bilateral cerebral ischemia under brief halothane anesthesia (nontreated group) and pentobarbital anesthesia (treated group). Mortality in the two groups was also evaluated. In nontreated animals, both saturated and mono- and polyunsaturated FFAs increased approximately 12-fold in total at the end of a 30-min period of ischemia; during recirculation, the level of free arachidonic acid dropped rapidly, while other FFAs gradually decreased to their preischemic levels in 90 min. In treated animals, the levels of total FFAs were lower than the nontreated group during ischemia, but higher at 90 min of reflow, and the decrease in the rate of free arachidonic acid was slower in the early period of reflow. Water content increased progressively during ischemia and recirculation with no extravasation of serum protein, but the values were consistently lower in the treated group. None of the nontreated animals survived for 2 weeks; in contrast, survival was 37.5% in the treated group. It is suggested that barbiturate protection from transient cerebral ischemia may be mediated by the attenuation of both membrane phospholipid hydrolysis during ischemia and postischemic peroxidation of accumulated free arachidonic acid.

The authors reviewed the computed tomographic (CT) scans of patients with subarachnoid hemorrhage whose initial angiograms were negative, to investigate the validity of CT scans in predicting the presence of an angiographically missed aneurysm in such patients. During the past 14 years, additional angiograms have been obtained for 38 of the 45 patients with subarachnoid hemorrhage whose initial angiograms disclosed no aneurysm. Aneurysms were found in 8 patients; 7 on the anterior communicating artery and 1 at the junction of the internal carotid and posterior communicating arteries. CT scans were taken within 4 days after subarachnoid hemorrhage in 31 patients. Analysis of these scans showed that the second angiogram revealed 1) an aneurysm in 21% of the patients with a thin layer of subarachnoid blood and in 63% of those with a thick layer; 2) no aneurysm in the patients without subarachnoid blood; and 3) an aneurysm of the anterior communicating artery in 70% of the patients who showed a considerable amount of blood in the basal frontal interhemispheric fissure. These results suggest that if CT scans show thin or thick subarachnoid blood, angiographic study should be repeated early in the course. If a considerable amount of blood is shown in the basal frontal interhemispheric fissure, it is highly probable that an aneurysm is hidden on the anterior communicating artery, even if the angiogram is negative for an aneurysm.

The authors conducted a prospective comparative study on the recurrence rate of chronic subdural hematoma after the use of two different treatment modalities: burr-hole irrigation of the hematoma cavity with (Group A) and without closed-system drainage (Group B). Thirty-eight patients were studied. Patients were assigned to groups sequentially upon admission. There were no significant differences between the two groups for age, sex, preoperative hematoma volume, and density on computed tomographic scan. One patient in Group A (5%) suffered a recurrence as opposed to 6 in Group B (33%). The difference in recurrence rate between the two groups was statistically significant (P less than 0.05). The authors conclude that closed-system drainage after burr-hole irrigation reduces the recurrence rate of chronic subdural hematoma.