Search

Purpose: Corpus callosotomy is a palliative surgical procedure for patients with drug-resistant epilepsy and suffering from drop attacks, which are a source of major deterioration in quality of life and can be responsible for severe traumatic injury. The objective of this study is to identify clinical markers that would predict a better outcome in terms of drop attacks and other types of epileptic seizures., Methods: We reviewed a retrospective series of children who underwent complete corpus callosotomy at our institution, between January 1998 and February 2019. We analyzed the neurological and cognitive pre- and postoperative status, radiological datas, and electroencephalography (EEG) monitoring data., Results: Fifty children underwent a complete callosotomy at a mean age of 7.5 years. The median postoperative follow-up was 42.5 months. Forty-one patients (82%) had a favorable outcome, 29 (58%) of them becoming totally free of drop attacks. Statistical analysis of correlation between outcome of drop attacks and the characteristics of the patients did not find any trend in terms of age, etiology or developmental level. Regarding seizure types, the probability of being drop attack-free was significantly higher in case of tonic seizures (p = 0.017). Neurological complications occurred in two patients. A transient disconnection syndrome was observed in one child with good preoperative cognitive level. The mean hospital stay was short (5 -10 days)., Conclusion: The results of this large monocentric case series with a long follow-up indicate that total callosotomy is a safe and effective treatment for children with drug-resistant epileptic drop attacks. Aside from a better surgical outcome for children with tonic seizures causing the falls, the lack of any other significant prognostic factor implies that no patient should a priori be excluded from this palliative surgical indication., (Copyright © 2022. Published by Elsevier Ltd.)

Stereoelectroencephalography-guided radiofrequency-thermocoagulation (SEEG-guided RF-TC) consists of coupling SEEG investigation with RF-TC stereotactic lesioning directly through the recording electrodes. In this systematic review the surgical technique, indications, and outcomes are described. Maximum accuracy is reached when a frame-based procedure with a robotic assistance and a per-operative vascular X-ray imaging are performed. Monitoring of the lesioning procedure based on the impedance, a sharp modification of which indicates that the thermocoagulation has reached its maximum volume, allows the optimization of the lesion size. The first indication concerns patients in whom a SEEG is required to determine whether surgery is feasible and in whom resection is indeed possible. Even if surgery is performed owing to insufficient efficacy of SEEG-guided RF-TC, the procedure remains interesting owing to its high positive predictive value for good outcome after surgery. The second indication concerns patients in whom phase I non-invasive investigations have concluded to surgical contraindication and who may still undergo SEEG in a purely therapeutic perspective (small deep zones inaccessible to surgery and network nodes of large epileptic networks). Lastly, SEEG-guided RF-TC can be considered as a first-line treatment for periventricular nodular heterotopia (PNH). Independently of indication, the overall seizure-free rate is 23% and the responder rate is 58%. The best results are obtained for PNH (38% seizure-free and 81% responders), while the worst results have been reported for temporal lobe-epilepsy in a dedicated study. The overall complication rate is 2.5%. More evidence is needed to help determine the exact place of SEEG-guided RF-TC in the surgical management algorithm., (Copyright © 2019 British Epilepsy Association. Published by Elsevier Ltd. All rights reserved.)

We propose expert recommendations on the use of SEEG-guided radiofrequency thermocoagulation (RF-TC) based on an exhaustive literature review. This technique consists in performing a RF-TC lesion using a SEEG depth electrode at the end of the recording. It is indicated when conventional surgical resection of the ictal onset zone is not possible. SEEG guided RF-TC can also be considered as a diagnostic tool since an improvement, even limited, has a high positive predictive value concerning the good outcome after surgery. It is possible to perform SEEG only in the purposes of performing RF-TC. An over-implantation of the presumed ictal onset zone is possible when such a procedure is planned. The RF-TC target should only be defined based on the ictal activity, except when a type II focal cortical dysplasia electrophysiological interictal signature is recorded. A single or multiple coagulations should always be performed between contiguous electrode contacts. The power delivered by the generator should be increased until the impedance suddenly changes, which indicates that the thermocoagulation has occurred. The procedure should be performed under clinical monitoring without anesthesia and after systematically testing neurological functions by electric stimulation on each target. Multiple SEEG-guided RF-TC can be proposed in a single patient, for example, in cases of relapse after a previous effective procedure. Conventional resection surgery remains feasible after a RF-TC procedure., (Copyright © 2017 Elsevier Masson SAS. All rights reserved.)

Stereoelectroencephalography (SEEG) was designed and developed in the 1960s in France by J. Talairach and J. Bancaud. It is an invasive method of exploration for drug-resistant focal epilepsies, offering the advantage of a tridimensional and temporally precise study of the epileptic discharge. It allows anatomo-electrical correlations and tailored surgeries. Whereas this method has been used for decades by experts in a limited number of European centers, the last ten years have seen increasing worldwide spread of its use. Moreover in current practice, SEEG is not only a diagnostic tool but also offers a therapeutic option, i.e., thermocoagulation. In order to propose formal guidelines for best clinical practice in SEEG, a working party was formed, composed of experts from every French centre with a large SEEG experience (those performing more than 10 SEEG per year over at least a 5 year period). This group formulated recommendations, which were graded by all participants according to established methodology. The first part of this article summarizes these within the following topics: indications and limits of SEEG; planning and management of SEEG; surgical technique; electrophysiological technical procedures; interpretation of SEEG recordings; and SEEG-guided radio frequency thermocoagulation. In the second part, those different aspects are discussed in more detail by subgroups of experts, based on existing literature and their own experience. The aim of this work is to present a consensual French approach to SEEG, which could be used as a basic document for centers using this method, particularly those who are beginning SEEG practice. These guidelines are supported by the French Clinical Neurophysiology Society and the French chapter of the International League Against Epilepsy., (Copyright © 2017 Elsevier Masson SAS. All rights reserved.)

Background: In some cases of drug-resistant focal epilepsy, noninvasive presurgical investigation may be insufficient to identify the ictal onset zone and the eloquent cortical areas. In such situations, invasive investigations are proposed using either stereotactic electroencephalography (SEEG) or subdural grid electrodes. Meta-analysis suggests that SEEG is safer than subdural grid electrodes, but insular implantation of SEEG electrodes has been thought to carry an additional risk of intraparenchymal hemorrhagic complications. Our objectives were to determine whether an insular SEEG trajectory is a risk factor for intracranial hematoma and to report the global safety of the procedure and provide some guidelines to prevent and detect complications., Methods: In a retrospective analysis of a surgical series of 525 consecutive procedures between 1995 and 2015, all electrodes were classified according to their insular or extrainsular trajectory. All complications were classified as major or minor according to their potential consequences regarding patient neurologic status., Results: Four intraparenchymal hematomas, all related to extrainsular electrodes (4/4974; 0.08%) were reported; no hematoma was found along insular electrodes (0/1042; 0%). There were 8 major complications (1.52%): 7 intracranial hematomas (1.33%) and 1 case of meningitis. Two patients had long-term neurologic impairment (0.38%), and 1 death (not directly related to the procedure) occurred (0.19%). Eleven minor complications (2.09%) were encountered, including broken electrode (1.52%), acute pneumocephalus (0.38%), and local cutaneous infection (0.19%)., Conclusions: SEEG is a safe procedure. Insular trajectories cannot be considered an additional risk of intracranial bleeding., (Copyright © 2016 Elsevier Inc. All rights reserved.)

Background: Deep brain electrodes have been used for the past 10 years to produce bipolar stereo-electro-encephalography-guided radiofrequency thermocoagulation (SEEG RF-TC). However, this technique is based on empiric knowledge. The aim of this study is 3-fold: 1) provide in vivo animal data concerning the effect of bipolar RF-TC on brain and its safety; 2) assess the parameters of this procedure (current delivery and dipole selection) that produce the most efficient lesion; and 3) provide technical guidelines., Methods: First we achieved in vivo RF-TC on rabbit brains with several conditions (power delivered and lesioning duration) and analyzed their influence on the lesion produced. Only a difference in terms of volume was found, and type of histologic lesions was similar whatever the settings were. We then performed multiple RF-TC in vitro on egg albumen, first with several parameters of radiofrequency and then with different dipole spatial selections. The end point was the size of the radiofrequency thermolesion produced., Results: Using unfixed parameters of radiofrequency current delivery and increasing it until the power delivered by the generator collapsed produced significantly larger lesions (P = 0.008) than other conditions. Concerning the dipole selection, the use of contiguous contacts on electrodes led to lesions with a higher volume (P = 7.7 × 10 -13 ) than those produced with noncontiguous ones., Conclusion: Besides the target selection in SEEG RF-TC, which is summarized on the basis of a literature review, we report the optimal parameters: Radiofrequency current must be increased until the power delivered collapses, and dipoles should be constituted by contiguous electrode contacts., (Copyright © 2016 Elsevier Inc. All rights reserved.)