Epilepsy surgery

The epilepsy surgery is the treatment of epilepsy by neurosurgical procedures. It is a tried and tested form of treatment in specialized centers. If the drug treatment of epilepsy does not lead to a satisfactory living situation, the possibility of epilepsy surgical treatment should be examined. This usually requires an in-patient presurgical evaluation.

indication

Only in focal, that is, focal epilepsies, can the area of ​​the brain ("epileptogenic area") that cause the attacks be removed. With electrocorticography it is possible to isolate the triggering nerve tissue with an accuracy of a few millimeters. The risk that surgical removal of this area can lead to disturbances in well-being , behavior or cognitive performance should be reduced by pre-surgical epilepsy diagnostics; it cannot be safely eliminated. A temporary implantation of electrodes under the skull or even in the brain (depth electrode) can give precise information about the location of the seizure and a prediction of the memory performance after the operation. This minimizes the risk of too many nerve cells being removed and is of great importance because the focus is often directly adjacent to areas of the memory or the language center (see waking craniotomy ). In addition to this special examination, imaging methods such as magnetic resonance imaging (MRT) and functional magnetic resonance imaging (fMRI) play an important role.

to form

In temporal lobe epilepsy with mesial temporal sclerosis , an anterior temporal lobe resection or selective resection of the tonsil nucleus and hippocampus can be performed.

Focal resection of the lesion or malformation is often performed, but the corpus callosum can also be severed as a callosotomy , or all connections in a hemisphere are severed , as a hemispherotomy or even the removal of a complete hemisphere known as a hemisphere . In the latter, severe neurological disorders, especially language disorders ( aphasia ), generalized muscular hypotension and hemiplegia ( hemiplegia ) are inevitable.

Results

Since the techniques vary widely and the localization varies greatly from person to person, there are few well-conducted studies that reflect reliable results from epilepsy surgery. The postoperative outcome of epilepsy surgery is classified according to Engel's classification.

In a meta-analysis of uncontrolled studies with children suffering from treatment-refractory epilepsy, 74% of children with a focal lesion and 45% of those without a focal lesion were found to be seizure-free after one year.

pathology

A European consortium of 36 centers in 12 European countries and under the leadership of the German neuropathological reference center for epilepsy surgery at the University Hospital Erlangen , the EEBB ( European Epilepsy Brain Bank ), has processed the resected brain samples for over 25 years and searched for pathological findings. Samples from 9,523 patients with treatment-refractory epilepsy were evaluated. At the time of surgery, 73% of patients were adults, but 76% had epilepsy for the first time in childhood and adolescence. 52% of the patients were male. The temporal lobe was affected in 72% of the procedures . Of the 7,168 patients for whom data were available, 61% were seizure-free after one year (66% in adolescents, 59% in adults). A total of 36 different pathological diagnoses could be made, which can be summarized in seven diagnostic clusters:

• Hippocampal sclerosis , also known as mesial temporal sclerosis , was the most common diagnosis at 36% (45% of adults, 15% of adolescents). After one year, 61% of the patients were seizure-free.
• Tumors were the second most common diagnostic group with 24%, with ganglioglioma being the most common with 10% of all patients. 83% of gangliogliomas were located in the temporal lobe.In addition, dysembryoplastic neuroepithelial tumors were found in 6% of all patients , which in turn was also in the temporal lobe in 68% were localized. Other tumors were angiocentric gliomas , gangliocytomas, isomorphic astrocytomas , pilocytic astrocytomas , neurocytomas , pleomorphic xanthoastrocytomas, and low-grade neuroepithelial tumors. 79% of all tumors were classified as “ low grade ”, low malignant (WHO grade 1). Across all tumors, 80% of adolescents, 64% of adults (and 68% of all patients) were seizure-free after one year.
• Malformations of the cortical development were found in 20% of the samples, but at 39% they were the most common diagnosis in adolescents. Focal cortical dysplasia subtypes were the most common malformations, which together accounted for 70% of malformations. The combination of dysmorphic neurons and balloon cells as a characteristic of type II was found most frequently with 45% and was present in 17% of all adolescents. Focal cortical dysplasia type II was most common in the frontal lobe (52%) . Overall, 58% of all patients were seizure-free after one year, 60% of adolescents and 55% of adults.
• No lesion was found in the pathological work-up in 7% of all patients, which, however, also included non-specific reactive gliosis , and other, recently described histopathological diagnoses such as oligodendroglial hyperplasia or hyaline protoplasmic astrocytopathy could also be found among them. After one year there was no seizure in 50% (adolescents 55%, adults 49%).
• Vascular malformations were found in 6%, especially cavernous angiomas in the temporal lobe. The onset of the seizure was in the middle of 22 years of age, the latest mean onset among all epilepsy pathologies. 65% were seizure-free after one year (adolescents 73%, adults 63%)
• Glian scars were found in 5%, mostly in the temporal lobe or in several places. At 61%, men and boys were affected significantly more frequently than women and girls. The rate of seizure-free patients after one year was lowest among all clusters, at 47%.
• Encephalitis - an inflammation of the brain was found in all samples only 1.5%, mainly Rasmussen's encephalitis in several lobes. Seizure freedom after one year was found in 50% of the patients.

literature

Individual evidence

1. ↑ J. Engel, Jr .: Surgery for seizures. In: N. Engl. J. Med. 1996; 334 (10), pp. 647-652. PMID 8592530 (review article)
2. ↑ Angel classification /
3. ^ JF Tellez-Zenteno L. Hernández Ronquillo, F. Moien-Afshari, S. Wiebe: Surgical outcomes in lesional and non-lesional epilepsy: a systematic review and meta-analysis Epilepsy Research 2010: Volume 89, pages 310-318
4. ↑ Ingmar Blumcke, Roberto Spreafico, Gerrit Haaker, Roland Coras, Katja Kobow, Christian G. Bien, Margarete Pfäfflin, Christian Elger, Guido Widman, Johannes Schramm, Albert Becker, Kees P. Braun, Frans Leijten, Johannes C. Baayen, Eleonora Aronica, Francine Chassoux, Hajo Hamer, Hermann Stefan, Karl Rössler, Maria Thom, Matthew C. Walker, Sanjay M. Sisodiya, John S. Duncan, Andrew W. McEvoy, Tom Pieper, Hans Holthausen, Manfred Kudernatsch, H. Joachim Meencke , Philippe Kahane, Andreas Schulze-Bonhage, Josef Zentner, Dieter H. Heiland, Horst Urbach, Bernhard J. Steinhoff, Thomas Bast, Laura Tassi, Giorgio Lo Russo, Cigdem Özkara, Buge Oz, Pavel Krsek, Silke Vogelgesang, Uwe Runge, Holger Lerche, Yvonne Weber, Mrinalini Honavar, José Pimentel, Alexis Arzimanoglou, Adriana Ulate-Campos, Soheyl Noachtar, Elisabeth Hartl, Olaf Schijns, Renzo Guerrini, Carmen Barba, Thomas S. Jacques, FJ Helen Cross, Martha Feucht, Angelika Mühlebner, Thomas Grunwald, Eugen Trinka, Peter A. Winkler, Antonio Gil-Nagel, Rafael Toledano Delgado, Thomas Mayer, Martin Lutz, Basilios Zountsas, Kyriakos Garganis, Felix Rosenow, Anke Hermsen, Tim J. von Oertzen, Thomas L. Diepgen, Giuliano Avanzini, for the EEBB Consortium: Histopathological Findings in Brain Tissue Obtained during Epilepsy Surgery New England Journal of Medicine 2017, Volume 377, Issue 17 of October 26, 2017, pages 1648–1656, DOI: 10.1056 / NEJMoa1703784

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