A Research Of Early Surgical Treatment And Pathology In Pediatric Intractable Epilepsy

Background and objectiveEpilepsy is a large class of recurrent transient cerebral dysfunction syndrome, characterized by recurrent epileptic seizures caused by abnormal neurons firing in the brain. According to the WHO research, the annual incidence of epilepsy in our country is about 35-45/100000, and the prevalence rate is about 0.7%. While the annual incidence of pediatric epilepsy (excluding febrile convulsion) is 151/100000, and the prevalence rate is about 3.45% Children, especially young children is an important component part of epilepsy patients. This maybe due to epilepsy is often caused by a variety of reasons, and these reasons are more common in children. Congenital disease, trauma, inflammation, tumor, cerebrovascular disease, poisoning are common in clinical. Generally, children would be treated as various antiepileptic drugs (AEDs) at the first time, but some children would gain poor drug efficacy, manifestating intractable epilepsy with recurrent epileptic seizures, although they had received regular medication and the blood drug concentration reached normal. In clinical work we need to consider operation for such patients.Surgical treatment of epilepsy started in late 19th Century, but its development in the pediatric field was very slow. This might be because part of epilepsy duration could be self-limiting, there was higher risk in pediatric operation and surgical technology was not mature enough then. Since 1970s, along with the rapid development of microneurosurgery, the safety of microsurgery gained great improvement, surgical treatment of epilepsy made great progress too at the same time. However, explicitly locating the epileptogenic focus, improving the pertinency and operation effect was plaguing epilepsy surgeons. Since the new century started, with the help of positron emission tomography (PET), single photon emission computed tomography (SPECT), functional magnetic resonance (fMRI) and other new technology of imaging, as well as neurophysiological monitoring technology such as invasive intracranial electrode monitoring, electrocorticography (ECoG), the possibility of locating the epileptogenic focus before and in operation has increased greatly. Epileptic surgery ushered a new development opportunity once again.This study summarized the data of 56 cases of intractable epilepsy accepted surgical treatment by Department of Neurosurgery of Guangdong General Hospital from Jan 2008 to Aug 2013 retrospectively, aiming to analyze the treatment effect caused by different operation, pathogeny, pathology and clinical manifestations, and summarize the rule.Methods1. General situation:According to the inclusion criteria, the data of 56 cases of intractable epilepsy accepted surgical treatment by Department of Neurosurgery from Jan 2008 to Aug 2013 were collected, including 31 cases of male,25 cases female. The age ranged from 1 to 14 years old, with an average age of 6.7 years old. All of the children in the group were diagnosed by physician of pediatric department or neurology department, and they accepted at least two kinds of regular treatment with antiepileptic drugs, but epileptic seizure controlling is not ideal. Considering the diagnosis of intractable epilepsy, medication might have poor prognosis, affect the development of intelligence and cause psychomotor disorders.2. Pre-operative examination:After admission the history of disease and epileptic seizures symptoms of children were documented, the previous imaging and electrophysiological examination reports were read, and patients underwent enhanced MRI scanning and (or). PET, SPECT examination, EEG, sphenoidal electrode EEG, flash stimulation EEG,24 hours of video EEG. According to the above three kinds of non-invasive preoperative examination the epileptogenic focus of patients were preliminary evaluated.3. Operation manner selecting:According to whether the seizure symptoms were accordant with the imaging, electrophysiological examination of patients, epileptogenic focus were preliminary predicated, and the operation manner, the excision sites would be drawn up. Then it would be further confirmed by ECoG in operation. For those cases which showed structural change on imaging, such as those who suffered low class gliomas or cortical dysplasia, if the symptoms and imaging, electrophysiology were accordant, the epileptogenic focus could be confirmed. If the epileptic focus was in the non-functional areas, lobectomy of the lesion located was considered first. While above three aspects were not accordant, preoperative 24h video EEG again would be recommended, in order to eliminate the "false epileptogenic focus" which would interference judgment, and intraoperative ECoG would be recommended to get further confirm. If the lesions were located in the important functional areas, multiple subpial transection (MST) would be considered. If the epileptic focus were not identified finally, only Palliative operation cound be performed, such as Incision of corpus callosum and (or) MST.For those cases which was negative on imaging, only symptoms and nerve-electrophysiological examination would be relied on, and prudent policy would be adopted when epileptogenic focus was checking. Sometimes, physicians, surgeons and electrophysiology physicians needed to assess together. It would be more important to receive ECoG in operation.Determining epilepsy side, after large bone flap craniotomy,20 guide cortical electrode monitoring was adopted, epileptogenic focus would be located again according to the intraoperative epileptic firing. After illumination resection of the epileptogenic focus would be carried out in non-functional area, if the epileptogenic focus was still not entirely confirmed or located in important functional areas, corpus callosotomy and (or) low power subpial thermocoagulation, subpial transection in functional area would be recommended. Intraoperative 20 guide cortical electrode monitoring would be carried out again after operation, observing the epileptic firing, comparing with preoperative situation, and documenting its reduction, or disappearance.4. Post-operative management:Patients undertook head computer X-ray tomography (CT) after operation, in order to know whether there was intracranial hematoma, infarction, cerebral edema and other complications, some children with positive imaging undertook MRI scan in order to observe the resection scope, and preliminary evaluating the operation effect and prognosis. AEDs would be given to children continuously after operation, outpatient follow-up would be undertaken also. The times of postoperative epileptic seizure should be documented after three months in order to evaluate the effect of operation conditions according to the Engel grading.Result1. All children received head CT scan after operation, which showed no severe complications of intracranial hemorrhage, infarction, cerebral hernia in all patients.3 children occurred hemiplegia, and partly recovered after rehabilitation therapy.5 children occurred acute disconnection syndrome, and gradually restored after treatment of 2-3 weeks. There were no severe neurological deficits, no death case. Intra-operative ECoG monitoring showed epileptic firing disappeared in 23 cases; epileptic firing mostly reduced, leaving a small amount of spike waves in 18 cases; leaving much spike waves in 14 cases. All patients obtained postoperative followed up after discharge, which durations of time were 1 to 5 years, with an average time of 2.8 years. When subsequent visit after three months, according to Engel grading, there were 40 cases of Engel grade I, accounting for 71.4%; 7 cases of grade II, accounting for 12.5%; 5 cases of grade III, accounted for 8.9%; 4 patients with grade IV, accounted for 7.1%. There were much spike waves in all of the patients who were Engel Ⅲ and Ⅳ three months after operation.4 cases of children occurred epileptic recurrence, including 2 cases due to low grade glioma recurrence, who didn’t occur epileptic recurrence again after second operation resecting tumor.2. In this group, according to the imaging and preoperative or intraoperative electrophysiological examination, the epileptogenic foci of 48 cases can be located, the operation manner of whom were resection of the epileptogenic foci in 42 cases and function area MST in 6 cases. The curative effect three months after operation were below:Engel grade Ⅰ in 37 cases, grade Ⅱ in 7 cases, grade Ⅲ in 4 cases; the good rate was 91.7% (44/48). The epileptogenic foci of 8 cases could not be located, the operation manner of whom were low power subpial thermocoagulation combined with corpus callosotomy in 5 cases, temporal lobe resection combined with corpus callosotomy in 1 case, and corpus callosotomy in 2 cases. The curative effect three months after operation were below:Engel grade Ⅰ in 3 cases, grade Ⅲ in 1 case, grade Ⅳ in 4 cases; the good rate was 37.5%(3/8).3. The results of Paraffin sections of children are below:focal cortical dysplasia in 16 cases; hippocampal sclerosis in 7 cases; gliomas in 11 cases, including 5 cases of ganglioglioma, and 6 cases of dysembryoplastic neuroepithelial tumor; cerebrovascular malformation in 3 cases, including 2 cases of arteriovenous malformation, and 1 case of cavernous hemangioma. Dual pathological results in 5 cases, hippocampal sclerosis with cortical dysplasia in 2 cases and hippocampal sclerosis with gliomas in 3 cases. There were 6 cases gained no specific pathological diagnosis, showing decrease, vacuolar degeneration and structure disorder of neurones, and mesenchyme vascular hyperemia, focal hemorrhage, gliocyte proliferation, neuronal degeneration, and neurotropic phenomenon.4. In this group,9 cases were diagnosed as epilepsy syndrome, including 5 cases of West syndrome,3 cases of Lennox-Gastaut syndrome,1 case of Sturge-Weber syndrome. The duration time of these children were diagnosed the epilepsy syndrome were less than 1 year, and taking AEDs regularly before operation, with still repeated epileptic seizures. The frequency was 1 times/day to dozens of times/days. The curative effect three months after operation were below:Engel grade I in 5 cases, grade II in 2 cases, and grade III in 2 cases.Conclusion1.For those children with structural change, such as the medial temporal lobe epilepsy with hippocampal sclerosis, focal cortical dysplasia, brain tumors, cerebrovascular disease, in case of their symptoms, imaging are accordant with electrophysiological examinations, radical resection of seizure foci would be recommended, and the curative effect would be confirmed.2. For those children with special types of epilepsy syndromes, curative effect of AEDs would mostly be poor. As long as they received 2 or 3 types of AEDs regularly, manifesting epileptic seizure, we should consider early intervention instead of waiting 2 years. Individual operation manner would be selected according to pre-operative evaluation.3. There were various pathological findings in pediatric intractable epilepsy. Hippocampal sclerosis and focal cortical dysplasia were Most common, and others included tumors, cerebrovascular diseases. Sometimes there were dual pathology, or no specific diagnosis. showing decrease, vacuolar degeneration and structure disorder of neurones, and mesenchyme vascular hyperemia, focal hemorrhage, gliocyte proliferation, neuronal degeneration, and neurotropic phenomenon.