Surgical treatment of temporal lobe epilepsy: comparative results of selective amygdalohippocampectomy versus anterior temporal lobectomy from a referral center in Brazil / Tratamento cirúrgico da epilepsia do lobo temporal: resultados comparativos da amigdalohipocampectomia seletiva versus lobectomia temporal anterior em um centro de referência no Brasil

Abstract Background Temporal lobe epilepsy (TLE) is a high prevalence neurological disorder. Surgery has emerged as a promising treatment. Objective The objective of this work is to compare the surgical results of anterior temporal lobectomy (ATL) versus selective amygdalohippocampectomy (SAH) in a cohort of 132 patients. Methods We performed a retrospective study of 146 patients operated for TLE from 2008 to 2019. Initially, 13 patients were excluded from the study due to insufficient medical record data or follow-up loss. One patient was excluded from the analysis of the results due to death in the first postoperative week. We used the ILAE scale to classify seizure control after surgery. In patients with left hippocampal sclerosis, SAH was performed and in right temporal lobe epilepsy, ATL was the approach of choice. Results The mean follow-up time after surgery was 57.2 months (12-137). In our data analysis, we found that the group of patients undergoing ATL had a higher prevalence of being completely seizure-free (ILAE I) (57.1% versus 31%) and a higher rate of satisfactory seizure control (88.6% versus 69.3%) p = 0,006, when compared with patients undergoing SAH. Conclusions The literature is still controversial about seizure control concerning the technique used due to the lack of a robust methodology. Our data analysis identified the superiority of ATL over SAH in seizure outcomes. ATL may be the best option for adequately controlling seizures with minimal additional morbidity in countries with a cost limitation for extended propaedeutics.

Resumo Antecedentes A epilepsia do lobo temporal (TLE) é uma desordem neurológica de alta prevalência. A cirurgia surgiu como um tratamento promissor. Objetivo O objetivo deste trabalho é comparar os resultados da lobectomia temporal anterior (ATL) versus amigdalohipocampectomia seletiva (SAH) em uma coorte de 132 pacientes. Métodos Realizamos um estudo retrospectivo de 146 pacientes operados por TLE de 2008 a 2019. Inicialmente, 13 pacientes foram excluídos por insuficiência de dados em prontuário ou perda de seguimento. Um paciente foi excluído da análise por óbito na primeira semana de pós-operatório. Usamos a escala ILAE para classificar o controle das crises após a cirurgia. Em pacientes com esclerose hipocampal à esquerda, foi realizada a SAH, e na epilepsia do lobo temporal à direita, a ATL foi a abordagem de escolha. Resultados O tempo médio de seguimento após a cirurgia foi de 57,2 meses (12-137). Em nossa avaliação, encontramos que o grupo de pacientes submetidos à ATL apresentou maior prevalência de ausência total de crises (ILAE I) (57,1% versus 31%) e maior taxa de controle satisfatório da epilepsia (88,6% versus 69,3%) p = 0,006, quando comparado ao grupo submetido à SAH. Resultados A literatura ainda é controversa em relação à redução das crises de acordo com a técnica utilizada devido a falta de uma metodologia robusta. Nosso estudo identificou superioridade da ATL sobre a SAH nos desfechos convulsivos. ATL pode ser a melhor opção para controlar adequadamente as convulsões com morbidade adicional mínima em países com limitação de custo para propedêutica estendida.

Alteraciones psiquiátricas tras lobectomía temporal anterior: reporte de casos / Psychiatric alterations after previous temporal lobectomy: Report of cases and review

RESUMEN Introducción: La lobectomía temporal anterior (LTA) es un procedimiento quirúrgico comúnmente utilizado para el tratamiento de la epilepsia del lóbulo temporal refractario al tratamiento médico, con altas tasas de éxito en el control de las crisis. Sin embargo, se ha descrito una asociación importante con enfermedades psiquiátricas que puede afectar al resultado posquirúrgico en estos pacientes. Métodos: Se exponen 2 casos representativos de pacientes que sufrieron complicaciones psiquiátricas en el posoperatorio de lobectomía temporal anterior, a pesar del control exitoso de las crisis. Resultados: Un varón sin antecedentes de enfermedad mental que sufre un episodio depresivo mayor en el periodo posoperatorio mediato, y una mujer con psicosis previa que evidencia exacerbación de su afección como complicación quirúrgica. Conclusiones: La enfermedad psiquiátrica se puede presentar en pacientes posoperatorios de epilepsia de lóbulo temporal tanto con antecedentes de enfermedad mental como sin ellos. Las alteraciones más frecuentes reportadas son depresión, ansiedad, psicosis y trastornos de la personalidad. La inclusión de evaluaciones psiquiátricas en los protocolos prequirúrgicos y posquirúrgicos pueden llevar a una mejora en el pronóstico de los resultados neurológicos y mentales de los pacientes sometidos a la intervención.

ABSTRACT Introduction: Anterior temporal lobectomy (LTA) is a surgical procedure commonly used for the treatment of temporal lobe epilepsy refractory to medical management, with high success rates in the control of seizures. However, an important association with psychiatric illnesses has been described that can alter the postoperative outcome in these patients. Methods: A series of 2 cases of patients who, despite successful crisis control, developed psychiatric complications in the postoperative period of anterior temporal lobectomy. Results: The cases included a male patient with no history of previous mental illness, who developed a major depressive episode in the postoperative period, and a female patient with previous psychosis who presented as a surgical complication exacerbation of psychosis, diagnosed with paranoid schizophrenia. Conclusions: Psychiatric disorders can occur in postoperative temporal lobe epilepsy patients with or without a history of mental illness. The most frequent alterations reported are depression, anxiety, psychosis and personality disorders. The inclusion of psychiatric evaluations in the pre- and post-surgical protocols can lead to an improvement in the prognosis of the neurological and mental outcomes of the patients undergoing the intervention.

Memoria episódica posterior a cirugía de epilepsia del lóbulo temporal / Episodic memory after temporal lobe epilepsy surgery

RESUMEN INTRODUCCIÓN: La cirugía resectiva del lóbulo temporal anterior con amigdalo-hipocampectomía es un tratamiento efectivo para la epilepsia farmacorresistente del lóbulo temporal con esclerosis hipocampal. Sin embargo, este procedimiento conlleva riesgo de deterioro de la memoria episódica verbal y no verbal postoperatoria, dependiendo de la dominancia hemisférica para la memoria y el lenguaje. OBJETIVO: Explorar el desenlace de la memoria episódica posterior a la cirugía resectiva mediante lobectomía temporal anterior con amigdalo-hipocampectomía. MÉTODOS: Se analizó retrospectivamente la memoria episódica verbal y no verbal mediante pruebas neurop-sicológicas de 51 pacientes consecutivos sometidos a lobectomía temporal anterior con amigdalo-hipocampectomía del lado izquierdo y derecho. Todos los pacientes fueron sometidos a resonancia magnética cerebral preoperatoria, video-electroencefalografía y evaluaciones neuropsicológicas. A 12 pacientes (24 %) no se les realizó el test de Wada. RESULTADOS: Hubo disminución en la memoria episódica verbal postoperatoria con diferencias respecto a la preoperatoria, en la subprueba de textos II recuerdo de la escala de memoria de Wechsler III (p = 0,035). El resultado en la memoria episódica visual se mantuvo igual, no hubo diferencias en el grupo de lobectomía temporal estándar. CONCLUSIÓN: La lobectomía temporal anterior más amigdalo-hipocampectomía izquierda afecta levemente el desempeño de la memoria episódica postoperatoria, que clínicamente no es significativo en pacientes con epilepsia del lóbulo temporal mesial farmacorresistente.

SUMMARY INTRODUCTION: Resective surgery of the anterior temporal lobe with amygdalohippocampectomy is an effective treatment for drug-resistant epilepsy of the temporal lobe with hippocampal sclerosis. However, this procedure carries a risk of post-operative episodic verbal and nonverbal memory impairment depending on the hemispheric dominance for memory and language. OBJECTIVE: To explore the outcome of episodic memory after resective surgery by means of anterior temporal lobectomy with amygdalohippocampectomy. METHODS: Verbal and non-verbal episodic memory was retrospectively analyzed by neuropsychological tests of 51 consecutive patients undergoing anterior temporal lobectomy with amygadalohyppocampectomy on the left and right sides. All patients underwent preoperative brain MRI, video electroencephalography, and neuropsychological evaluations. 12 patients (24%) did not undergo the Wada test. RESULTS: There was a decrease in postoperative verbal episodic memory with differences compared to preoperative, in the text II subtest recall of the Wechsler III memory scale (p = 0.035). The result in visual episodic memory remained the same, there were no differences in the standard temporal lobectomy group. CONCLUSION: Anterior temporal lobectomy plus left amygadalohyppocampectomy slightly affects the performance of postoperative episodic memory, which is clinically not significant in patients with drug-resistant mesial temporal lobe epilepsy.

A Primer on Magnetic Resonance-Guided Laser Interstitial Thermal Therapy for Medically Refractory Epilepsy

Epilepsy surgery that eliminates the epileptogenic focus or disconnects the epileptic network has the potential to significantly improve seizure control in patients with medically intractable epilepsy. Magnetic resonance-guided laser interstitial thermal therapy (MRgLITT) has been an established option for epilepsy surgery since the US Food and Drug Administration cleared the use of MRgLITT in neurosurgery in 2007. MRgLITT is an ablative stereotactic procedure utilizing heat that is converted from laser energy, and the temperature of the tissue is monitored in real-time by MR thermography. Real-time quantitative thermal monitoring enables titration of laser energy for cellular injury, and it also estimates the extent of tissue damage. MRgLITT is applicable for lesion ablation in cases that the epileptogenic foci are localized and/or deep-seated such as in the mesial temporal lobe epilepsy and hypothalamic hamartoma. Seizure-free outcomes after MRgLITT are comparable to those of open surgery in well-selected patients such as those with mesial temporal sclerosis. Particularly in patients with hypothalamic hamartoma. In addition, MRgLITT can also be applied to ablate multiple discrete lesions of focal cortical dysplasia and tuberous sclerosis complex without the need for multiple craniotomies, as well as disconnection surgery such as corpus callosotomy. Careful planning of the target, the optimal trajectory of the laser probe, and the appropriate parameters for energy delivery are paramount to improve the seizure outcome and to reduce the complication caused by the thermal damage to the surrounding critical structures.

A Primer on Magnetic Resonance-Guided Laser Interstitial Thermal Therapy for Medically Refractory Epilepsy

Epilepsy surgery that eliminates the epileptogenic focus or disconnects the epileptic network has the potential to significantly improve seizure control in patients with medically intractable epilepsy. Magnetic resonance-guided laser interstitial thermal therapy (MRgLITT) has been an established option for epilepsy surgery since the US Food and Drug Administration cleared the use of MRgLITT in neurosurgery in 2007. MRgLITT is an ablative stereotactic procedure utilizing heat that is converted from laser energy, and the temperature of the tissue is monitored in real-time by MR thermography. Real-time quantitative thermal monitoring enables titration of laser energy for cellular injury, and it also estimates the extent of tissue damage. MRgLITT is applicable for lesion ablation in cases that the epileptogenic foci are localized and/or deep-seated such as in the mesial temporal lobe epilepsy and hypothalamic hamartoma. Seizure-free outcomes after MRgLITT are comparable to those of open surgery in well-selected patients such as those with mesial temporal sclerosis. Particularly in patients with hypothalamic hamartoma. In addition, MRgLITT can also be applied to ablate multiple discrete lesions of focal cortical dysplasia and tuberous sclerosis complex without the need for multiple craniotomies, as well as disconnection surgery such as corpus callosotomy. Careful planning of the target, the optimal trajectory of the laser probe, and the appropriate parameters for energy delivery are paramount to improve the seizure outcome and to reduce the complication caused by the thermal damage to the surrounding critical structures.

Clinical outcomes after medial temporal lobe epilepsy surgery: Anterior temporal lobectomy versus selective amygdalohippocampectomy / 中南大学学报(医学版)

Objective:To compare the anterior temporal lobectomy (ATL) with transsylvian selective amygdalohippocampectomy (SeAH) in 72 patients with medial temporal lobe epilepsy (MTLE) regarding the seizure control and neuropsychological outcomes.Methods:Clinical data and follow-up data were collected and retrospectively analyzed.SeAH and ATL were used in 39 and 33 patients,respectively.All eligible patients were followed up at least one year.Wechsler Adult Intelligence Scale-Revised and the Wechsler Memory Scale-Revised were used to test the patients' neuropsychology before and after the surgery for one year.Results:Fifty-nine patients (81.9％) achieved satisfactory seizure control (62.5％ Engel Class Ⅰ and 19.4％ Class Ⅱ).ATL obtained 84.8％ satisfactory seizure control (28 patients),and the success rate was 79.5％ (31 patients) for SeAH.There was no significant difference in seizure control between SeAH and ATL (P=0.760).The postoperative verbal IQ of SeAH group increased significantly in both side surgery (P＜0.05),while the increase was not significant in the group of ATL of both side surgery (P＞0.05).Regarding left-side surgery,postoperative verbal memory and total memory were increased significantly in the group of SeAH (P＜0.05),while the increases were not significant in the group ofATL (P＞0.05).In the right-side surgery,postoperative verbal memory and total memory were increased significantly in the two surgery strategy groups (P＜0.05),while no significant increases were seen in non-verbal memory of the two surgery strategy groups (P＞0.05).Conclusion:Microsurgery for the treatment of refractory MTLE is successful and safe,and should be encouraged.The seizure outcome is not different between ATL and SeAH,while regarding as verbal IQ and verbal memory outcomes,SeAH may be superior to ATL in dominant hemisphere surgery.

Transtemporal amygdalohippocampectomy: a novel minimally-invasive technique with optimal clinical results and low cost / Amigdalo-hipocampectomia transtemporal: técnica minimamente invasiva com ótimos resultados clínicos e baixo custo

ABSTRACT Mesial temporal sclerosis creates a focal epileptic syndrome that usually requires surgical resection of mesial temporal structures. Objective: To describe a novel operative technique for treatment of temporal lobe epilepsy and its clinical results. Methods: Prospective case-series at a single institution, performed by a single surgeon, from 2006 to 2012. A total of 120 patients were submitted to minimally-invasive keyhole transtemporal amygdalohippocampectomy. Results: Of the patients, 55% were male, and 85% had a right-sided disease. The first 70 surgeries had a mean surgical time of 2.51 hours, and the last 50 surgeries had a mean surgical time of 1.62 hours. There was 3.3% morbidity, and 5% mild temporal muscle atrophy. There was no visual field impairment. On the Engel Outcome Scale at the two-year follow-up, 71% of the patients were Class I, 21% were Class II, and 6% were Class III. Conclusion: This novel technique is feasible and reproducible, with optimal clinical results.

RESUMO A esclerose mesial temporal é uma síndrome epiléptica focal que requer ablação de estruturas mesiais temporais. Objetivo: Descrever e padronizar a técnica operatória e resultados clínicos. Métodos: Série prospectiva de casos de uma única instituição, realizadas por um único cirurgião, de 2006 a 2012. 120 doentes foram submetidos a amigdalo-hipocampectomia transtemporal por acesso mínimo (keyhole). Resultados: 55% eram do sexo masculino, 85% apresentavam doença do lado direito. As primeiras 70 cirurgias tiveram um tempo cirúrgico médio de 2,51 horas, e as últimas 50 cirurgias tiveram um tempo cirúrgico médio de 1,62 horas. Houve morbidade de 3,3%. 5% dos doentes apresentaram atrofia leve de músculo temporal. O controle das convulsões foi avaliado com a Escala de Engel no segundo ano de pós operatorio, 71% eram Classe I, 21% Classe II, 6% Classe III. Conclusão: Esta nova técnica é viável, reprodutível e com resultados clínicos adequados.

Potential role of a cognitive rehabilitation program following left temporal lobe epilepsy surgery / Reabilitação neuropsicológica em pacientes com epilepsia submetidos à lobectomia temporal dominante

ABSTRACT Research into memory and epilepsy has focused on measuring problems and exploring causes with limited attention directed at the role of neuropsychological rehabilitation in alleviating post-operative memory difficulties. Objectives To assess the effects of a memory rehabilitation program in patients with left temporal lobe epilepsy following surgery. Methods Twenty-four patients agreed to participate and 18 completed the study; nine received memory rehabilitation while nine had no input and were designated as controls. Verbal learning efficiency, naming abilities, memory subjective ratings, ecological activity measures and a language fMRI paradigm were used as outcome measures. Results Improved verbal learning and naming test performance, increase in memory strategy use and improved self-perception were observed following the rehabilitation. Changes in fMRI activation patterns were seen in the rehabilitation group over the long term. Conclusion The findings support the potential role of a cognitive rehabilitation program following left temporal lobe surgery.

RESUMO As publicações na área de epilepsia e memória se focam em mensurar prejuízos e investigar causas, com poucos dados sobre reabilitação neuropsicológica em pacientes pós-cirúrgicos. Objetivos Avaliar os efeitos da reabilitação neuropsicológica em pacientes submetidos a lobectomia temporal dominante. Métodos Vinte e quatro pacientes iniciaram o estudo, apenas dezoito o concluíram, dos quais 9 foram participantes de sessões de reabilitação com enfoque em memória. Todos os participantes foram avaliados quanto a autopercepção de dificuldades de memória; ao uso de estratégias para minimizar tais dificuldades; a habilidade de nomeação e a aprendizagem verbal e foram submetidos à ressonância magnética funcional. Resultados Foi encontrado efeito significativo da reabilitação neuropsicológica na autopercepção de dificuldades de memória; no uso de estratégias compensatórias; na aprendizagem verbal e na nomeação. Alterações no padrão de ativação na RMf foram observadas no grupo submetido a reabilitação. Conclusão A reabilitação neuropsicológica pode beneficiar pacientes submetidos a lobectomia temporal antero-mesial dominante com prejuízos de memória.

Anterior temporal lobectomy versus selective amygdalohippocampectomy in patients with mesial temporal lobe epilepsy / Lobectomia temporal anterior versus amigdalohipocampectomia seletiva para epilepsia de lobo temporal mesial

ABSTRACT Objective To contribute our experience with surgical treatment of patients with mesial temporal lobe epilepsy (mTLE) undergoing anterior temporal lobectomy (ATL) or selective amygdalohippocampectomy (SelAH). Method This is a retrospective observational study. The sample included patients with medically refractory mTLE due to unilateral mesial temporal sclerosis who underwent either ATL or SelAH, at Hospital de Clinicas – UFPR, from 2005 to 2012. We report seizure outcomes, using Engel classification, cognitive outcomes, using measurements of verbal and visuospatial memories, as well as operative complications. Result Sixty-seven patients (33 ATL, 34 SelAH) were studied; median follow-up was 64 months. There was no statistically significant difference in seizure or neuropsychological outcomes, although verbal memory was more negatively affected in ATL operations on patients’ dominant hemispheres. Higher number of major complications was observed in the ATL group (p = 0.004). Conclusion Seizure and neuropsychological outcomes did not differ. ATL appeared to be associated with higher risk of complications.

RESUMO Objetivo Contribuir com nossa experiência para o tratamento cirúrgico de pacientes com epilepsia do lobo temporal mesial submetidos a lobectomia temporal anterior (LTA) ou amigdalohipocampectomia seletiva (AHS). Método Estudo retrospectivo observacional. Foram incluídos pacientes com epilepsia refratária devido a esclerose mesial temporal unilateral, submetidos a LTA ou AHS no Hospital de Clínicas – UFPR, entre 2005-2012. Foram comparados os resultados cognitivos (análises de memórias verbal e visuoespacial), controle de crises (Engel) e complicações cirúrgicas. Resultados Sessenta e sete pacientes (33 LTA, 34 AHS) foram estudados; o período de acompanhamento médio foi de 64 meses. Não houve diferença no controle das crises ou resultado neuropsicológico, mas a memória verbal foi mais negativamente afetada nos pacientes submetidos à LTA no hemisfério dominante. Maior número de complicações graves ocorreu no grupo de LTA (p = 0.004). Conclusão Controle de crises e resultados neuropsicológicos não diferiram. LTA pareceu estar associada a um maior risco cirúrgico.

Preliminary investigation on memory outcomes following selective amygdalohippocampectomy versus anterior temporal lobectomy for temporal lobe epilepsy and hippocampal sclerosis / 中国神经精神疾病杂志

Objective To investigate the different memory outcomes in temporal lobe epilepsy patients underwent different surgical approaches.Methods Two hundred forty-eight patients with temporal lobe epilepsy and hippocampal scle-rosis underwent standard anterior temporal lobectomy ( ATL, n=83 ) or selective amygdalohippocampectomy ( SAH, n=165) from 2009 to 2013.All the patients underwent clinical memory function assessment before surgery, 3 months and 2 years after surgery respectively.Results The memory quotient ( MQ) of patients who underwent brain surgery in the domi-nant hemisphere significantly decreased 3 months after surgery (74.5 ±16.2, 75.6 ±19.5) compared to presurgery MQ (82.9 ±15.8, 83.2 ±21.2) in both ATL and SAH groups (P<0.05).Although MQ was slightly recovered at 2 years af-ter surgery, MQ (75.1 ±14.1, 76.1 ±17.6) was still significantly lower compared with presurgery MQ (P<0.05).A-mong this, both the decrease extent of the MQ 3 months after surgery and 2 years after surgery were smaller in the SAH group than in the ATL group (7.6 vs.8.4;7.1 vs.7.8).The MQ of patients who underwent brain surgery in the non-dominant hemisphere (either ATL or SAH ) increased slightly 3 months after surgery (87.2 ±15.1, 88.1 ±16.9) com-pared to presurgery MQ (85.5 ±13.5, 85.3 ±19.7) although the difference was not statistically significant.The MQ of these two groups improved significantly 2 years after surgery (92.8 ±12.7, 93.7 ±17.1)(P<0.05).The improvement extent of the MQ was larger in the SAH group than in the ATL group (8.4 vs.7.3).Conclusions SAH may be better than ATL in the maintenance of memory function in patients with temporal lobe epilepsy and hippocampal sclerosis.

Correlation between extratemporal hypometabolism and the outcome of temporal lobectomy in patients with temporal lobe epilepsy / 中华核医学与分子影像杂志

Objective To explore the correlation between extratemporal hypometabolism on preoperative 18F-FDG PET imaging and the outcome after temporal lobectomy in temporal lobe epilepsy (TLE)patients.Methods A total of 96 patients with intractable TLE who underwent temporal lobectomy were recruited.The outcome was evaluated according to International League Against Epilepsy (ILAE) 2001 outcome classification (OC) criteria:OC 1-3 was considered as good outcome and OC4-6 as poor outcome.The follow-up period was more than 2 years.The 18F-FDG PET brain images were retrospectively analyzed.The preoperative extratemporal cortical hypometabolism and extratemporal subcortical hypometabolism occurred in basal ganglia and thalamus were taken as independent exposure factors of poor outcome and the odds ratios (OR) were calculated respectively.Results Thirteen of 96 cases had poor outcome.Extratemporal cortical hypometabolism was found in 12 of 83(14.5％) cases with good outcome and in 11 of 13 cases with poor outcome.Extratemporal subcortical hypometabolism was found in 25 of 83 (30.1％) cases with good outcome and in 10 of 13 cases with poor outcome.The occurrence of extratemporal hypometabolism was significantly higher in poor outcome group than that in good surgical outcome group (cortical:x2 =26.63 ;subcortical:x2 =8.70; both P＜0.05).The OR of extratemporal cortical hypometabolism was 32.54,with 95％ CI of 6.40-165.44,and that of extratemporal subcortical hypometabolism was 7.73,with 95％ CI of 1.96-30.52.Conclusion Extratemporal cortical hypometabolism and subcortical hypometabolism in TLE patients are associated with poor outcome of temporal lobectomy in TLE patients.

Effects of Anterior Temporal Lobectomy for Mesial Temporal Lobe Epilepsy on Intellectual and Memory Functions: 1-Year Follow-up

BACKGROUND: The aim of this study was to identify factors predicting intellectual and memory changes following anterior temporal lobectomy (ATL) for mesial temporal lobe epilepsy (TLE). METHODS: The sample consisted of 31 patients who underwent ATL for treatment of medically intractable TLE. All patients were administered intellectual and memory tests preoperatively and postoperatively. RESULTS: All statistically significant intellectual and memory changes at 1-year follow-up were in the direction of improvement. Left vs. right ATL had significantly differential effects on verbal intelligence and verbal memory, reflecting greater decline (or less improvement) following a left ATL. A later onset age of seizures, an older age at surgery, and a higher presurgical cognitive performance predicted a greater cognitive decline following an ATL. CONCLUSIONS: At 1-year after ATL, most cognitive functions showed either no significant changes or significant changes in a favorable direction. Decreased verbal functions following a left ATL was the area of greatest potential neuropsychological morbidity associated with ATL. Greater cognitive decline following ATL was predicted by later onset age of recurrent seizures, older age at time of surgery, and higher presurgical cognitive performance.

Epilepsy Surgery I

Epilepsy is a chronic neurological disorder manifesting recurrent unprovoked epileptic seizures. About 20~30% of epilepsy patients are resistant to antiepileptic medications. These patients suffer from high risk of physical injury, unemployment, marital problem, and psychological stress. Epilepsy surgery is the firstly recommended treatment modality for the patients with medically intractable epilepsy. Presurgical evaluation is the most important process for performing epilepsy surgery. The ultimate goal of the presurgical evaluation in patients with medically refractory partial seizures is the localization of the epileptogenic zone and the resection of which is also both necessary and sufficient to render the patient seizure-free. The localization of the epileptogenic zone derives from a hierarchical synthesis of localizing data independently obtained from clinical, electrographic, neuroimaging, and neuropsychological examination. In addition, closely related to the goal of localizing the epileptogenic zone is the significant need for anticipating the risks of functional deficits that could derive from the surgical resection. Mesial temporal lobe epilepsy (TLE) is the best candidate for epilepsy surgery. Anterior temporal lobectomy with amygdalohippocampectomy is a surgical treatment method for mesial TLE and its seizure-free rate (SFR) is 60~90%, whereas one-year SFR of antiepileptic drug treatment for mesial TLE is 10~20%. Cortisectomy is a surgical method for extratemporal epilepsy and its SFR is about 40~70%. Corpus callosotomy is a partial or complete division of corpus callosum for preventing seizure propagations between right and left hemispheres and is effective for controlling atonic seizures. The variation of postsurgical seizure outcomes is related to the qualities of epilepsy surgery program, presurgical evaluation and surgical techniques. For the good surgical outcome, the epilepsy surgery program should include neurologist, neurosurgeon, neuropsychologist, neuro-radiologist and neuro-nuclear medicine specialist for a comprehensive team approach.

Epilepsy Surgery II

Epilepsy surgery is classified into two types: curative epilepsy surgery and palliative surgery. The most frequently performed curative epilepsy surgery is an anterior temporal lobectomy with amygdalohippocampectomy (ATL with AH). ATL with AH includes the resection of epileptic hippocampus/amygdala and anterior temporal lobe (3~4cm from temporal pole) and is performed for treating drug refractory mesial temporal lobe epilepsy. A literature reports that more resection of epileptic hippocampus had a better surgical outcome. However, a surgery should be planned to prevent or minimize a postsurgical memory decline especially in resection of a dominant temporal lobe. Cortisectomy is a resection of localized epileptic focus in patients with neocortical epilepsy such as frontal, parietal, occipital, and lateral temporal lobe epilepsies. Most of neocortical epilepsy patients need an intracranial electrode implantation for determination of resection margin and a brain stimulation on intracranial electrodes for functional mapping. For a successful cortisectomy, an epilepsy surgery team should have a good amount of knowledge and experiences in intracranial EEG monitoring for intractable epilepsy patients. It is very important to place the intracranial electrodes at a brain region where epileptic focus is located because a wrong placement of intracranial electrodes results in failure of surgery. The surgical principles of functional hemispherectomy (FH) aim at disconnecting the hemisphere while leaving as much of the ipsilateral brain as possible intracranially; it has been characterized as anatomically subtotal but physiologically complete hemispherectomy. The original technique consists of a large central tissue removal, complete callosotomy, frontal and parieto-occipital disconnection, temporal lobectomy and insular corticectomy. The candidates of FH are drug refractory partial epilepsy patients who have unilateral epileptic focus and severe brain damage in ipsilateral hemisphere with loss of finger movements of contralateral hand. Corpus callosotomy is a surgical technique severing the corpus callosum so that communication between the cerebral hemispheres is interrupted. In contrast with lobectomy, corpus callosotomy does not involve removing any brain tissue. Instead, it usually involves cutting the front two-thirds of this bundle (anterior callosotomy). Sometimes the other one-third is cut later (complete callosotomy). Corpus callosotomy is most effective for atonic seizures ("drop attacks"), less effective for tonic-clonic seizures and tonic seizures. Additionally, multiple subpial transection and neurostimulation techniques are described.

The Statistical Parametric Mapping Analysis between Pre- and Post-Operative FDG-PET Images in Patients with Mesial Temporal Lobe Epilepsy / 대한간질학회지

BACKGROUND: To investigate postoperative changes in the cerebral glucose metabolism of patients with mesial temporal lobe epilepsy (MTLE), statistical parametric mapping (SPM) analysis was performed on pre- and post-operative 18F-fluorodeoxy glucose positron emission tomographic (FDG-PET) images. METHODS: We included 28 patients with MTLE who had under-gone surgery and had been seizure free postoperatively (16 had left MTLE and 12 right MTLE). All patients showed hippocampal sclerosis by pathology or brain MRI. FDG-PET images of the 12 right TLE patients were reversed to lateralize the epileptogenic zone to the left side in all patients. RESULTS: Application of the paired t-test in SPM to pre- and postoperative FDG-PETs showed that the postoperative glucose metabolism decreased in the caudate nucleus, pulvinar of thalamus, fusiform gyrus, lingual gyrus, and in the posterior region of the insular cortex in the hemisphere ipsilateral to resection, whereas postoperative glucose metabolism increased in the anterior region of the insular cortex, temporal stem white matter, midbrain, inferior precentral gyrus, anterior cingulate gyrus, and supramarginal gyrus in the hemisphere ipsilateral to resection. No significant postsurgical changes of cerebral glucose metabolism occurred in the contralateral hemisphere. Subtraction between pre- and postoperative FDG-PET images in individual patients produced similar findings to the SPM results. CONCLUSION: This study suggests that brain regions showing a postoperative increase in glucose metabolism appear to represent the propagation pathways of ictal and interictal epileptic discharges in MTLE while a postoperative decrease in glucose metabolism may be related to a permanent loss of afferents from resected anterior-mesial temporal structures.

Predicting Factors of Long-term Surgical Outcome for Mesial Temporal Lobe Epilepsy with Unilateral Hippocampal Atrophy on MRI / 대한간질학회지

PURPOSE: To identify the clinical and electroencephalographic factors which are independently predictive of a postoperative seizure-free outcome for 4 years. We compared the outcomes of the first 2 years with the subsequent 2 years one after anterior temporal lobectomy (ATL) for mesial temporal lobe epilepsy (MTLE) with unilateral hippocampal atrophy (HA) on MRI. METHODS: We studied 51 consecutive operated patients who had above 4 years of follow-up and had MTLE with definite unilateral HA on MRI. The surgical outcome was classified as either seizure-free or not seizure-free in the first postoperative 2 years and the subsequent 2 years. Several clinical variables were included. The scalp EEG parameters included the lateralization of interictal epileptiform discharges, ictal onset location, ictal onset frequency, ictal EEG lateralization, and ictal scalp EEG propagation (bitemporal asynchrony or switch of lateralization). Variable factors were subjected to univariate analysis. RESULTS: Overall, 36 patients (71%) became seizure-free during the postoperative 4 years. On univariate analysis, only one factor was significantly associated with poor outcome (p<0.05): ictal scalp EEG propagation pattern such as bitemporal asynchrony or switch of lateralization. The seizure-free outcome was seen in 88.9% of patients without bitemporal asynchroncy, or switch of lateralization while only 54.5% of patients with those patterns (p=0.007) during the postoperative third and fourth year. However, those propagation patterns did not show the prognostic value during the first 2 years (p=0.449). Other variable factors were found not to be predictive of prognosis on early or late recurrence. CONCLUSIONS: Bitemporal asynchrony or a switch of lateralization in the ictal scalp EEG might be a highly predictive factor for an undesirable surgical outcome, late recurrence of seizure during a follow-up period after ATL, and probably an index of bitemporal epileptogenicity in MTLE.

The Effect of Resection Extent Upon Postoperative Outcome of Seizures and Memory in Anterior Temporal Lobectomy with Amygdalohippocampectomy / 대한간질학회지

PURPOSE: To investigate the relationship of the resection extent of hippocampus and temporal neocortex with the postsurgical outcome in patients with mesial temporal lobe epilepsy (TLE). METHODS: Sixty-eight patients with TLE underwent brain MRI pre- and post-operatively. They were divided into two groups by seizure outcomes:seizure free group (SF, N=54) and non-seizure free group (NSF, N=14). Patients were classified further according to the post-surgical memory changes:MD group (with postsurgical memory decline, N=15) and NMD group (without postsurgical memory decline, N=16). The hippocampal resection was estimated by subtracting the length of post-surgical hippocampus from the pre-surgical length. The resection of temporal neocortex was measured by comparing the resection lengths on superior, middle, inferior and basal temporal gyri shown on three dimensional brain MRI. RESULTS: The mean extent of hippocampal resection was significantly larger in SF than in NSF (33.2+/-7.5 mm vs. 24.8+/-7.4 mm p=0.001) while that between MD and NMD was not significantly different. The resection extent of temporal neocortex was not significantly different between SF and NSF as well as between MD and NMD, but the resection extent of basal temporal gyrus of left TLE was significantly larger in MD than in NMD. CONCLUSIONS: The hippocampal resection was significantly greater in SF. The overall resection extent of the temporal neocortex did not correlate to the surgical outcomes of seizures or memory although that of the basal temporal gyrus of the left TLE was larger in MD.

Prognostic Factors in Anterior Temporal Lobectomy for Mesial Temporal Lobe Epilepsy: Multivariate Analysis

BACKGROUND: In order to identify the prognostic factors of anterior temporal lobectomy (ATL) for mesial temporal lobe epilepsy (TLE), we performed multivariate analyses in patients with mesial TLE. METHODS: One hundred eighty six patients with mesial TLE (112 men and 74 women; mean age 28.9+/-8.7 years) were included. The primary outcome variable was a the patient's status in the third postoperative year: seizure free (except aura), or not. Clinical, electroencephalographic, radiological, intracarotid amobarbital test, and pathologic data were considered. Clinical data included age at surgery, age at nonfebrile seizure onset, duration of epilepsy, sex, seizure frequency, secondary generalization, history of febrile seizure, and existence of aura. RESULTS: One hundred fifty eight patients (84.9%) had remission of seizure. Univariate analysis found age at surgery (p=0.006) and MRI abnormality including hippocampal sclerosis ipsilateral to surgery (p=0.01) to be significant. Multivariate analyses using logistic regressions, the younger age at surgery (p=0.002) and MRI lateralization (p=0.02) were found to be the significant predictors for good surgical outcome. CONCLUSIONS: Age at surgery and hippocampal findings on MRI are independent prognostic factors for ATL in mesial TLE. These findings suggest that mesial TLE is a progressive disorder and surgical outcome is better when early ATL is performed, at least in medically intractable cases.

Surgical Outcome of Intractable Seizure with Space-Occupying Lesion in Temporal Lobe

OBJECTIVE: The increasing use of sensitive neuroimaging techniques has demonstrated that significant percentage of patients with intractable complex partial seizures have brain masses, especially in temporal lobe. The optimal surgical solution for these patients is still open to debate. The purpose of our investigation is to evaluate the surgical outcome of patient with lesion-related temporal lobe epilepsy with respect to the types of surgery and the location of lesion. PATIENTS AND METHODS: From DEC. 1993 to Dec. 1997, 35 patients with intractable epilepsy and space occupying temporal lobe lesion identified in preoperative MRI were included in this study. The types of surgery were lesionectomy, anterior temporal lobectomy with or without hippocampectomy. The location of lesion was divided as anteromedial group and lateral cortical group. The postoperative seizure outcomes according to the type of surgery and location of the lesion were compared. RESULTS: Twenty-six of 34 patients(76.5%) were seizure-free after surgery. The Engel's class was favorable after anterior temporal lobectomy with or without hippocampectomy(p=.044). CONCLUSION: It is favorable to perform anterior temporal lobectomy for the treatment of intractable epilepsy with space-occipying lesion in temporal lobe. The resection of the hippocampus can be individualized.

Surgical Application of Magnetic Resonance Imaging Anatomy for Temporal Lobe Epilepsy Surgery

Anterior temporal lobectomy is the most popular surgical method for mesiobasal temporal lobe epilepsy. The key point in anterior temporal lobectomy is to resect lateral neocortex as little as possible, and mesiobasal structures as much as possible without surgical complication. We analyzed surgical anatomy on MRI scans of 20 persons to evaluate the relationships of anatomical structures related with surgical steps in anterior temporal lobectomy. On the oblique axial scan, the distance from temporal pole to anterior margin of hippocampus was 29.8+/-1.5mm. The length of hippocampus to the level of posterior margin of cerebral peduncle was 25.6+/-2.4mm. On the oblique coronal image through hippocampal head, the distance between the surface of superior temporal sulcus and lateral margin of temporal horn roof was 32.5+/-2.2mm. The angle between middle fossa base line and the line connecting superior temporal sulcus and lateral margin of temporal horn roof was 33.6+/-5.2 degree. The distance between lateral temporal surface and brain stem, and that between lateral temporal surface and collateral sulcus was 49.9+/-1.9mm and 40.6+/-3.3mm, respectively. The distance between collateral sulcus and lateral margin of temporal horn roof was 14.2+/-1.8mm, and the angle between middle fossa base line and the line connecting lateral margin of temporal horn roof and collateral sulcus was 60.4+/-7.4 degree. On the sagittal image, the angle between superior temporal sulcus and hippocampal axis was 18.8+/-1.1 degree. In conclusion, surgical complication of anterior temporal lobectomy can be reduced by careful consideration of anatomical relationships between anatomical structures encountered in each surgical steps in anterior temporal lobectomy.