Preliminary Study On Preoperative Surgical Timing Decision And Interaoperative Electrophysiological Monitoring For Intracranial Aneurysms

PartⅠAnalysis on surgical timing for ruptured anterior circulation aneurysmsObjective:To investigate the appropriate timing of surgery for ruptured anterior circulation aneurysms.Methods: Eighty-two patients with ruptured anterior circulation aneurysms were analyzed retrospectively. They were divided into one low-grade group (GradeⅠtoⅢ, n=64) and one high-grade group (GradeⅣtoⅤ, n=18) according to the Hunt-Hess Scale on admission. Then they were also divided into early (≤3d, n=45),intermediate (4-10d, n=20) and late (≥11d, n=12) surgery groups according to their timing of surgery. Operations were not performed in 5 patients for rebleeding. The outcome was scored according to the Glasgow Outcome Scale (GOS).Results: In the low-grade group, the rate of good outcome (GOS 4-5) in the early surgery group was significantly higher than that in the intermediate and late surgery groups (96.3% vs. 75.0%, P=0.031), and the incidence of the major postoperative complications was significantly lower than that in the intermediate and late surgery groups (22.2% vs. 46.9%, P=0.049). Moreover, the rate of good outcome in the intermediate surgery group was significantly higher than that in the late surgery group (85.5% vs. 41.7%, P=0.004), and the incidence of the major postoperative complications was significantly lower than that in the late surgery group (30.0% vs. 75.0%, P=0.027). The patients in the high-grade group were all operated early, and their rate of good outcome was 55.6%.Conclusion: Early operation is advocated in patients with ruptured anterior circulation aneurysm of different grades. PartⅡPreliminary research on neuroelectrophysiological monitoring during intracranial aneurysm surgeryObjective : To explore the application of various intraoperative neuroelectro- physiological monitoring on somatosensory evoked potentials (SEPs), brainstem auditory evoked potentials (BAEPs), motor evoked potentials (MEPs) and electroencephalography (EEG) during intracranial aneurysm surgery.Methods: SEPs were monitored routinely during operations on 16 patients with intracranial aneurysms. Moreover, among these patients, scalp EEG, BAEPs and MEPs were monitored experimentally on 6, 3 and 2 cases, respectively. The relationship between the intraoperative changes of electrophysiological signals and the postoperative outcome of neurological deficits was valuated.Results:11 patients without abnormal intraoperative electrophysiological signal changes had no new neurological deficits after surgery. However, in the left 5 patients, abnormal changes of intraoperative electrophysiological signals were detected, including abnormal SEPs in 4 patients (1 also with abnormal BAEPs) and abnormal MEPs in 1 patient. Among these 5 patients, 1 with recovered electrophysiological signals had no neurological deficits, while 4 with abnormal electrophysiological signals which were not recovered intraoperatively demonstrated new developed functional deficits immediately after operation.Conclusion:During intracranial aneurysm surgery, SEP monitoring is important and necessary, while the value of scalp EEG monitoring is relatively limited. The combination of SEP and MEP monitoring in operations on anterior circulation aneurysms and the combination of SEP and BAEP monitoring in operations on posterior circulation aneurysms are very beneficial, not only to timely detect neurological functional deficits resulted from intraoperative cerebral ischemia, but also to properly guide surgical manipulation, and to reliably predict postoperative outcome as well.