Stereotactic Amygdalohippocampotomy For The Treatment Of Mesial Temporal Lobe Epilepsy

Background :The mechanism of stereotactic amygdalohippocampotomy to treat epilepsy: (1)eliminate Epileptogenic zone (2)block the propgate way of epileptic discharges(3)decrease excite of cortex to control seizure through lesioning in specific areas of brain. The targets lesioned in operation included amygadala, hippocampus, Forel-H,fornix, cingular gyrus, anterior commissure, globus pallidus, hypothalamus, internal capsule, corpus callosum, thalamus, and amygadala, hippocampus always were lesioned to treat temporal lobe epilepsy. Todays, manys scholar insisted that conbined targets lesioning can improve seizurs outcome. Amygadala,hippocampus are critical structure of limbic system. The amygdala which correlate with mood and behavior have important role in seizure onset. Lesioning in amygdala is not only effective for violence behavior, but also for seizure control. Hippocampus is involved in memory. For the specific redudant connections between hippocampus and neocortices , hippocampus is easy to produce epileptic discharges, hence became the most common epileptogenic zone. And lateral lesioning could not result in memory deficit. But which is most effective , lesioning in amygdala or hippocampus, or both? What information could be used to select targets and define extent of resection? These questions all have no answer.Objective: This study is to investigate the efficacy of stereotactic ablation of the amygadala and hippocampus for treatment of mesial temporal lobe epilepsy through extensive ablation, we sought to investigate the accuracy oflateralization and localization of interictal epileptic discharge recorded by depth electrode , also to determine whether it correlate with seizue outcome and could be used to define the extent of resection.Methods : This study was carried out retrospectively. We studied 21 patients with intractable temporal lobe epilepsy who underwent stereotactic amygdalohippocampotomy between 1998 and 2OO3.The effectiveness of stereotactic amygdalohippocampotomy for mesial temporal lobe epilepsy were evaluated. And the accuracy of lateralization and localization of depth electrode were investigated. Interictal epileptic discharge rates recorded by depth electrode occurred preoperatively and postoperatively were compared.Result: Of these patients with medial temporal lobe epilepsy who underwent stereotactic amygdalohippocampotomy ,62% became seizures free or experienced significant reduction in seizures severity and frequency, we found seizure free after operation in 56% patients whose scalp EEG and MRI are concordant. Using seizure outcome as golden standard , depth electrode record lateralized 62% patients for operation.As compared with prelesion ,no consistent changes of interictal epileptic discharge rates recorded by depth electrode occurred postoperatively.Conclusion: In our patients with stereotacticamygdalohippocampotomy .seizures outcome are not as good as those from selective amygdalohippocampotomy. The interictal epileptic discharge can supply useful lateralizing information, but have little localizing value.As compared with prelesion, no consistent changes occurred postoperatively. Postlesion rprelesion spike change failed to correlate with effectiveness of lesionectomy for seizue control.