Stereotactic Electroencephalography (seeg) in the Pre-surgical Investigation of Refractory Focal Epilepsy December 4, 2012 Case Hans O. Lűders Epilepsy Center Medical Center, University Hospitals, Cleveland 1 American Epilepsy Society Annual Meeting
Disclosure No commercial interest 2 American Epilepsy Society Annual Meeting 2012
Learning Objectives Recognize the usefulness of seeg as an invasive evaluation technique for defining the epileptogenic zone in candidates for epilepsy surgery 3 American Epilepsy Society Annual Meeting 2012
Invasive evaluation techniques in surgical candidates 5-10% of patients with epilepsy are candidates for epilepsy surgery and 25-50% of these patients will require invasive EEG studies (37,000 to 100,000 patients in USA alone) In the 1950 th two schools for invasive evaluation of surgical candidates with invasive electrodes emerged: in Europe, Taillarach and Bancaud developed the stereo EEG (s EEG) which analyses the brain in 3-D 4
Invasive evaluation techniques in surgical candidates in North America, however, Penfield and Jasper relied primarily on electrocorticography (ECoG) which led to the use of subdural electrodes, primarily a 2-D technique. 5
Invasive evaluation techniques in surgical candidates Surgically treatable focal epilepsy originates in the cortical grey matter. However, only 25-30% of the cortex is in the visible surface. In other words, 70-75% of the cortex is either deep seated or difficult if not impossible to access with subdural electrodes 6
Symposium overview Drs. Giorgio LoRusso and Jonathan Miller are going to discuss respectively the European and the American approach to depth electrode insertion Dr. Gonzalez-Martinez will compare depth and subdural electrodes Drs. Philippe Kahane and Samden Lhatoo will present the use of depth electrodes for respectively mapping the epileptogenic zone and eloquent areas of the brain We will conclude with a round table and answering questions from the audience 7
References Stereotaxic Approach to Epilepsy. J. Tailarach and J. Bancaud. Progr.neurol.Surg. vol5, pp.297-354, Karger, Basel 1973 Stereoencephalography in the Presurgical Evaluation of Focal Epilepsy: A Retrospective Analysis of 215 Procedures. Neurosurgery, vol. 57, pp. 706-718, 2005 8
Stereo-EEG methodology: the European approach 4 th December 2012 Giorgio LoRusso, M.D. Epilepsy Surgery Centre C. Munari Niguarda Hospital, Milano Italy American Epilepsy Society Annual Meeting 9
Disclosure No Commercial Interest American Epilepsy Society Annual Meeting 2012 10
Learning Objectives Rationale of the original Talairach s approach. Current 3D imaging-based SEEG methodology. American Epilepsy Society Annual Meeting 2012 11
The Talairach s methodology You have to know the Stereo TAXIC (three dimensional / arrangement) To perform a Stereo TACTIC (three dimensional / touch) approach 12
Jean Talairach s methodology 1949 Cerebral commissures Vessels QuickTime and a YUV420 codec decompressor are needed to see this picture. Ventriculography Angiography direct landmarks visualization But how get the 3D...? 13
The Talairach s proportional grid VCA-VCP The Quadrillage 14
MR in the pre MR era Fig. from Talairach and Tournoux 1988 inter-individual variability of cortical anatomy 3D world approach based on a proportional reference system which used the intercommissural line identified by contrast ventriculography Talairach J, Szikla G, Tournoux P, et al: Atlas d anatomie stéréotaxique du télencephale. Paris: Masson, 1967 15
Stereoscopic angiography 16
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Current SEEG Implantation Technique Positioning of the guiding screws Positioning of the robot Positioning of the stop system on the drill to reach the internal wall of the skull Drilling Coagulation of the dura mater with a monopolar coagulating electrode Positioning of the screw Implant of the electrodes (under X-Ray control) Temporary introduction of the stylet Introduction of the electrode Tightening of the cap QuickTime and a decompressor are needed to see this picture. 19
New SEEG Implantation Accuracy (Sep 2008 - Nov 2011) 1050 electrodes Localization error at EP (median) 0.78 mm (i.q. range: 0.49-1.08) Neurosurgery, in press 20
Safety (May 1996 - November 2011) 500 SEEG procedures Major morbidity Surgical intracranial bleeding Minor intracranial bleeding Cerebritis Hydrocephalus Retained broken electrode Psychotic event Death 500 SEEG 5 (2 permanent hemiplegias) 10 (1 with status epilepticus) 2 (1 aseptic) 1 1 1 1 Neurosurgery, in press 21
Today from 2D to 3D Today the main diagnostic acquisition are 3D But THE SONG REMAINS THE SAME First think stereotaxic and then stereotactic 22
Where are we recording from? 23
Neurophysiological individual localization 25
DTI-FT of the Cortico Spinal Tract SEEG stimulation and motor evoked potentials QuickTime and a decompressor are needed to see this picture. QuickTime and a decompressor are needed to see this picture. 26
The relevance of the 3D exploration 11 yrs. 27
The deep seated lesions 16 yrs. 28
16 yrs. White-Grey matter bundary surface with FDG- PET overlay The inflated representation
16 yrs. The neurophysiological label of the FCD J L K 31
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Periventricular Nodular Heterotopia Rt 11 electr Case 1: 24 yrs. SEEG exploration QuickTime and a decompressor are needed to see this picture. Lt 2 electr 33
Periventricular Nodular Heterotopia Case 1: 24 yrs. SEEG exploration QuickTime and a decompressor are needed to see this picture. 34
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Periventricular Nodular Heterotopia Case 2: 9 yrs. SEEG exploration figure da slicer con elettrodi intracerebrali 36
Periventricular Nodular Heterotopia Case 2: 9 yrs. SEEG exploration QuickTime and a decompressor are needed to see this picture. Red: the nodule Violet-Green: the CST 37
Periventricular Nodular Heterotopia Case 2: 9 yrs. SEEG ictal recordings 38
Periventricular Nodular Heterotopia Case 2: 9 yrs. SEEG guided thermocoagulation 39
Periventricular Nodular Heterotopia Case 2: 9 yrs. SEEG guided cortical resection 40
Impact on Clinical Care and Practice SEEG is a methodology for invasive EEG recording definition of the Epileptogenic Zone functional cortical and subcortical mapping thermocoagulation of the Epileptogenic Zone Accurate visualization of contact location (both cortical and subcortical) by multimodal imaging. Limited patient s discomfort. After the removal of the electrodes, all the collected SEEG data are available for an accurate and thoughtful interpretation before 41