Analysis on correlation factors of cerebral intragenic ischemia after temporary parent arterial occlusion during intracranial aneurysm surgery / 第三军医大学学报

Objective To identify the correlation factors associated with cerebral intragenic ischemia after temporary parent arterial occlusion in intracranial aneurysm surgery. Methods One hundred and eighteen patients who underwent temporary arterial occlusion in the 120 aneurysms (from a group of 324 consecutive aneurysm patients treated from 1996 to 2002) were reviewed retrospectively. These variables included sex, age, presence of preoperative subarachnoid hemorrhage (SAH), neurological clinical grade, operational timing, duration of arterial occlusion, numbers of temporary occlusion, mode of arterial occlusion, intraoperative aneurysm rupture, hypertension, the location of temporary occlusion, aneurysm size, hyperglycemia, atheromatous mass. Univariate and multivariate were used to investigate the relationship between the variates and postoperative ischemic changes. Results The total times of temporary occlusion were 156, with an average of 1.30. The duration of arterial occlusion ranged from 1 to 45 min (9.75?7.75). Seventeen patients (14.4%) demonstrated evidence of new infarction in the vascular territory subjected to temporary arterial occlusion. Conclusion In the univariate analysis, age, presence of preoperative SAH, duration of arterial occlusion, atheromatous mass are all significantly correlated with postoperative ischemic injuries. Multivariate logistic regression revealed that the age, older more than 60 (P= 0.010 3 , relative risk=4.335), and the duration of arterial occlusion, lasting more than 20 min (P= 0.032 9 , relative risk=4.177), have significant correlation with the injuries. Based on these findings, temporary occlusion is safe and useful in aneurysm surgery and the postoperative cerebral ischemia is less likely to occur when the duration of clipping is shorter than 20 min.

Prolonged Temporary Arterial Occlusion during Surgery for an Aneurysm of the Dorsal Internal Carotid Artery

The authors describe a case with an uneventful outcome following prolonged temporary arterial occlusion during surgery for an aneurysm of the dorsal internal carotid artery(ICA). It has been shown that in various situations arising during aneurysm surgery, temporary arterial occlusion effectively prevents a premature rupture. It is not possible, however, to predict beforehand what the permissible occlusion time for any individual patient might be. During dissection of a blister aneurysm of the ICA, premature rupture developed, and intermittent temporary occlusion of the ICA, which lasted for about 150 minutes, was then undertaken. In addition, intraoperative neuroprotection was effected in several ways, including intermittent reperfusion and the administration of mannitol, thiopental sodium and steroid. There were no significant postoperative neurological deficits. To the authors' knowledge, this report is unusual in that it documents prolonged temporary occlusion without major neurological sequelae in intracranial aneurysm surgery. Permissible temporary occlusion time and neuroprotective methods are also discussed.

The Effects of Continuous and Intermittent Interruption of the Cerebral Blood Flow on Brain Edema and Ischemic Neuronal Injury in Gerbils

Temporary occlusion of the cerebral blood flow is an effective maneuver to prevent and/or to control excessive bleeding during neurosurgical operations. Many studies have been reported employing single occlusion of various durations. However, there has been only a few studies examing the consequences of repeated occlusions on the development of cerebral edema and neuronal injury in the gerbil. Three separate episodes of 5-minute ischemia spaced at varied time interval was produced in Mongolian gerbils by occlusion of bilateral common carotid arteries. Quantitative estimates of cerebral edema and neuronal injury were obtained 24 hours after the third occlusion. The result was compared to that of single 15-minute occlusion. In gerbils with three 5-minute occlusions at 10-minute intervals, cerebral edema was not significant. However, the animals killed 24 hours after three 5-minute occlusions at 1-hour intervals or single 15-minute occlusion showed severe cerebral edema. Such animals showed significantly more neuronal injury than in animals with three 5-minute occlusions at 10-minute intervals. These results suggest that ischemic brain damage may be reduced with repeated vascular occlusions spaced at short intervals.

Somatosensory Evoked Potentials Before and During Surgery in Patient with Cerebral Aneurysm

It has been known that the electrical activity of the brain is related to regional cerebral blood flow, and cerebral ischemia developed during the management of aneurysmal subarachnoid hemorrhage(SAH) is one of the major causes of morbidity and mortality. Somatosensory evoked potentials(SEPs) in response to median nerve stimulation at wrist have been recorded before and during surgery in 31 patients with aneurysmal SAH and 30 normal control subjects. The central conduction time(CCT), the time between the N4 peak recorded from the second cervical spine and the N20 peak recorded from the sensory cortex, were observed as an indicator of cortical activity. The results were as follows, 1) In patients with aneurysmal SAH, CCT recorded before surgery were not different from that of controls. 2) In patients with aneurysmal SAH, CCT recorded during surgery were found to be significantly increased by administration of anesthetics. 3) During surgery in aneurysmal SAH, CCT tended to be increased by brain retraction. 4) During surgery in aneurysmal SAH, CCT changes relative to the temporary occlusion of the parent artery were quite variable, ranging from rapid disappearance of N20 by only 2 minutes of temporary occlusion to no significant change after 20 minutes of occlusion. The rapid disappearance of N20 within 2 minutes after temporary occlusion was highly likely to be associated with appreciable neurologic deficit after surgery. These results suggest that somatosensory evoked potentials during the management of patients with aneurysmal SAH is considered to be a valuble indicator of cortical function, especially when temporary occlusion was performed to prevent premature rupture of cerebral aneurysm during surgery.