Pierre Bourdillon1, Jean Isnard2, Hélène Catenoix2, Alexandra Montavont3, Sylvain Rheims4, Philippe Ryvlin5, Karine Ostrowsky-Coste6, François Mauguiere7, Marc Guénot8. 1. Department of Neurosurgery, Hospital for Neurology and Neurosurgery Pierre Wertheimer, Hospices Civils de Lyon, Lyon, France; Université de Lyon, Université Claude Bernard, Lyon, France; Sorbonne Universités, Université Pierre et Marie Curie, Paris, France. Electronic address: pierre.bourdillon@neurochirurgie.fr. 2. Department of Functional Neurology and Epileptology, Hospital for Neurology and Neurosurgery Pierre Wertheimer, Hospices Civils de Lyon, Lyon, France. 3. Department of Functional Neurology and Epileptology, Hospital for Neurology and Neurosurgery Pierre Wertheimer, Hospices Civils de Lyon, Lyon, France; Department of Sleep, Epilepsy and Pediatric Clinical Neurophysiology, Hospital for Neurology and Neurosurgery Pierre Wertheimer, Hospices Civils de Lyon, Lyon, France. 4. Université de Lyon, Université Claude Bernard, Lyon, France; Department of Functional Neurology and Epileptology, Hospital for Neurology and Neurosurgery Pierre Wertheimer, Hospices Civils de Lyon, Lyon, France; Neuroscience Research Center of Lyon, Lyon, France. 5. Neuroscience Research Center of Lyon, Lyon, France; Department of Clinical Neurosciences, Centre Hospitalo-Universitaire Vaudois, Lausanne, Switzerland. 6. Department of Sleep, Epilepsy and Pediatric Clinical Neurophysiology, Hospital for Neurology and Neurosurgery Pierre Wertheimer, Hospices Civils de Lyon, Lyon, France. 7. Université de Lyon, Université Claude Bernard, Lyon, France; Sorbonne Universités, Université Pierre et Marie Curie, Paris, France; Department of Functional Neurology and Epileptology, Hospital for Neurology and Neurosurgery Pierre Wertheimer, Hospices Civils de Lyon, Lyon, France. 8. Department of Neurosurgery, Hospital for Neurology and Neurosurgery Pierre Wertheimer, Hospices Civils de Lyon, Lyon, France; Université de Lyon, Université Claude Bernard, Lyon, France; Neuroscience Research Center of Lyon, Lyon, France.
Abstract
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.
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.