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Clínica de Epilepsia | Trabalhos na Íntegra

ELECTROCORTICOGRAPHIC FINDINGS IN A PATIENT WITH TEMPORAL LOBE DUAL PATHOLOGY

Arthur Cukiert, Alcione Sousa, Cassio Forster, Viviane Ferreira, Meire Argentoni, Elcio Machado, Joaquim Vieira, José Buratini, Leila Frayman

Epilepsy Surgery Program, Hospital Brigadeiro and Clínica de Epilepsia de São Paulo, Sao Paulo SP, Brazil.

Introduction

The introduction of MRI in the clinical practice made it possible to diagnose preoperatively lesions that were previously not detected by CT scanning. Mesial temporal sclerosis (MTS) is the main pathological substrate of temporal lobe epilepsy. Some patients with TLE have been diagnosed as having dual pathology. MRI discloses MTS and another type of lesion in these patients (1-3). The association of MTS and neuronal migration disorders is the most frequent but vascular malformations and gliotic lesions may also coexist with MTS (4-5).

The surgical strategy in patients with dual pathology has been an issue of dispute in the literature. Surgical removal of both lesions have been advocated by some (6-8) but others consider the removal of only one of the lesions in many cases (9).

This paper reports on a patient with temporal lobe dual pathology and discusses the surgical strategy based on intraoperative electrocorticographic findings.

Case Report

F.A., a 32 years-old male presented with weekly refractory autonomic simple and complex partial seizures since the age of 12. His EEG showed a left temporal focus. MRI disclosed a cavernous angioma of the left uncus and left mesial temporal sclerosis (figure 1). He was submitted to surgery under general anesthesia and intraoperative electrocorticography (ECoG) performed with subdural grids and strips as needed. Four ECoG recordings were obtained: 1- preresection, 2- postcortical removal and exposure of the cavernoma and the hippocampus, 3- postcavernoma removal and 4- posthippocampectomy. After a basal ECoG recording (figure 2), a corticectomy involving the temporal convexity from the superior temporal to the fusiform gyrus was performed. After wide opening of the temporal horn, both the hippocampus and the siderotic margin of the cavernoma were exposed. A second ECoG sample was obtained and showed independent spiking coming from the hippocampus and the angioma with some synchronous spiking (figure 3). After the removal of the vascular malformation, a third ECoG was obtained and disclosed residual spiking from the hippocampus (figure 4). Complete hippocampectomy led to the total disappearance of the spikes. There was no surgical morbidity. Pathological examination confirmed both diagnosis suggested by MRI. The patient is seizure free 2 years after surgery.

Discussion

Up to 50% of the patients with cavernous angioma may present with epilepsy (10-11). The majority of them do not have refractory epilepsy but in some refractory seizures are present (12). In the majority of these patients there is a congruence of the topography of the lesion and the epileptic focus (13). On the other hand, a minority of them may have non-congruent results (14). This is especially true for patients with multiple cavernous angiomas, usually in the context of the genetic multiple cavernoma syndrome (15). Some patients may present with new cavernous angiomas over prolonged follow-up (16).

Despite different opinions regarding lesionectomy alone or resection of both lesions in patients with dual pathology, strong electrophysiological data favouring each of the procedures is lacking in the literature . The electrocorticographic findings shown in this paper provide an electrophysiological basis for the resection of both lesions (17), which has been our surgical strategy in these patients.

References

1- Levesque MF, Nakasato N, Vinters HV, Babb TL. Surgical treatment of limbic epilepsy associated with extrahippocampal lesions: the problem of dual pathology. J Neurosurgery 1991; 75:364-370.

2- Kuzniecky R, Ho SS, Martin R, Faught E, Morawetz R, Palmer C, Gilliam F. Temporal lobe developmental malformations and hippocampal sclerosis: epilepsy surgical outcome. Neurology 1999; 52:479-484.

3- Fisher RS, Blum D. Epilepsy surgery where there is dual pathology. Lancet 1999; 354:267-268.

4- Ho SS, Kuzniecky RI, Gilliam F, Faught E, Morawetz R. Temporal lobe developmental malformations and epilepsy: dual pathology and bilateral hippocampal abnormalities. Neurology 1998; 50:748-754.

5- Cendes F, Cook MJ, Watson C, Andermann F, Fish DR, Shorvon SD, Bergin P, Free S, Dubeau F, Arnold DL. Frequency and characteristics of dual pathology in patients with lesional epilepsy. Neurology 1995; 45:2058-2064.

6- Kamada K, Isu T, Takahashi T, Tanaka T. Remote epileptogenic focus detected by electrocorticogram in a case of cavernous angioma. Acta Neurochir (Wien) 1994; 127:236-239.

7- Mathern GW, Babb TL, Pretorius JK, Melendez M, Levesque MF. The pathophysiological relationships between lesion pathology, intracranial ictal EEG onsets and hippocampal neuron losses in temporal lobe epilepsy. Epilepsy Res 1995; 21:133-147.

8- Li LM, Cendes F, Andermann F, Watson C, Fish DR, Cook MJ, Dubeau F, Duncan JS, Shorvon SD, Berkovic SF, Free S, Olivier A, Harkness W, Arnold DL. Surgical outcome in patients with epilepsy and dual pathology. Brain 1999; 122:799-805.

9- Casey AT, Thomas DG, Harkness WF. Stereotactilly-guided craniotomy for cavernous angioma presenting with epilepsy. Acta Neurochir (Wien) 1995; 137:34-37.

10- Buckingham MJ, Crone KR, Ball WS, Berger TS. Management of cerebral cavernous angiomas in children presenting with seizures. Childs Nerv System 1989; 5:347-349.

11- Requena I, Arias M, Lopez-Ibor L, Pereiro I, Barba A, Alonso A, Monton E. Cavernous angioma of the central nervous system. Clinical and neuroimaging manifestations in 47 patients. J Neurol Neurosurg Psychiatry 1991; 54:590-594.

12- Giulioni M, Acciarri N, Padovani R, Galassi E. Results of surgery in children with cerebral cavernous angiomas causing epilepsy. Br J Neurosurgery 1995; 9:135-141.

13- Steiger HJ, Markwalder TM, Reulen HJ. Clinicopathological relations of cerebral cavernous angiomas: observations in eleven cases. Neurosurgery 1987; 21:879-884.

14- Ryvlin P, Mauguiere F, Sindou M, Froment JC, Cinotti L. Interictal cerebral metabolism and epilepsy in cavernous angiomas. Brain 1995; 118:677-687.

15- Zevgaridis D, van Velthoven V, Ebeling U, Reulen HJ. Acta Neurochir (Wien) 1996; 138:672-677.

16- Houteville JP. Brain cavernoma: a dynamic lesion. Surg Neurol 1997; 48:610-614.

17- Cascino GD, Jack CR, Parisi JE, Sharbrough FW, Schreiber CP, Kelly PJ, Trenerry MR. Operative strategy in patients with MRI-identified dual pathology and temporal lobe epilepsy. Epilepsy Res 1993; 14:175-182.

ACHADOS ELETROCORTICOGRÁFICOS EM UM PACIENTE COM PATOLOGIA DUPLA DO LOBO TEMPORAL.

Arthur Cukiert, Alcione Sousa, Cassio Forster, Viviane Ferreira, Meire Argentoni, Elcio Machado, Joaquim Vieira, Jose Buratini, Leila Frayman.

Serviço de Cirurgia de Epilepsia, Hospital Brigadeiro e Clínica de Epilepsia de São Paulo, Sao Paulo SP, Brasil.

Resumo

Introdução: A RMN é frequentemente capaz de detectar lesões, tais como a esclerose mesial temporal, responsáveis pela epilepsia do lobo temporal. Mais raramente, a RMN mostra duas lesões temporais potencialmente epileptogênicas. Nesta situação, discute-se a necessidade ou não de remover ambas ou somente uma destas lesões. Este estudo relata a neurofisiologia invasiva de paciente com dupla lesão temporal. Relato de caso: FS, de 32 anos, possuía CPS autonômicas e crises parciais complexas com automatismos desde os 12 anos. Seu EEG mostrava foco temporal esquerdo e RMN mostrava cavernoma de uncus e esclerose mesial temporal esquerda. Foi submetido à cirurgia guiada por eletrocorticografia (ECoG) sob anestesia geral. Após a abertura dural, foi realizada ECoG basal, que mostrou descargas ocupando todo o neocortex temporal anterior e médio. Após a remoção do córtex e abertura do corno temporal, expos-se o cavernoma e o hipocampo. Nova ECoG mostrou descargas a partir da região do cavernoma e do hipocampo de maneira independente, bem como descargas síncronas. Após a ressecção do cavernoma, ECoG cobrindo o hipocampo remanescente mostrou descargas a partir do mesmo. Após a hipocampectomia, desapareceram todas as descargas anormais. O paciente encontra-se sem crises desde a cirurgia. Discussão: Neste caso de dupla lesão foi possível determinar a multifocalidade das descargas. Caso esta seja a situação na maioria dos casos de dupla lesão temporal, sugere-se que dupla-lesionectomia seja o procedimento mais indicado nestes pacientes.

Palavras-chave: patologia dupla, epilepsia temporal, angioma cavernoso, cirurgia.

ELECTROCORTICOGRAPHIC FINDINGS IN A PATIENT WITH TEMPORAL LOBE DUAL PATHOLOGY.

Arthur Cukiert, Alcione Sousa, Cassio Forster, Viviane Ferreira, Meire Argentoni, Elcio Machado, Joaquim Vieira, Jose Buratini, Leila Frayman.

Summary

Introduction: Some patients with TLE have been diagnosed as having dual pathology. MRI discloses MTS and another type of lesion in these patients. The surgical strategy in patients with dual pathology has been an issue of dispute in the literature. This paper reports on a patient with temporal lobe dual pathology and discusses the surgical strategy based on intraoperative electrocorticographic findings. Case Report: F.A., a 32 years-old male presented with weekly refractory autonomic simple and complex partial seizures since the age of 12. His EEG showed a left temporal focus. MRI disclosed a cavernous angioma of the left uncus and left mesial temporal sclerosis . He was submitted to surgery under general anesthesia and intraoperative electrocorticography (ECoG). After a basal ECoG recording , a temporal corticectomy was performed. A second ECoG sample was obtained and showed independent spiking coming from the hippocampus and the angioma with some synchronous spiking. After the removal of the vascular malformation, a third ECoG was obtained and disclosed residual spiking from the hippocampus. Complete hippocampectomy led to the total disappearance of the spikes. The patient is seizure free 2 years after surgery. Discussion: Despite different opinions regarding lesionectomy alone or resection of both lesions in patients with dual pathology, strong electrophysiological data favouring each of the procedures is lacking in the literature . The electrocorticographic findings shown in this paper provide an electrophysiological basis for the resection of both lesions (17), which has been our surgical strategy in these patients.