Stereotactic placement of depth electrodes in medically intractable epilepsy

2014 ◽  
Vol 120 (3) ◽  
pp. 639-644 ◽  
Author(s):  
Jorge Gonzalez-Martinez ◽  
Jeffrey Mullin ◽  
Sumeet Vadera ◽  
Juan Bulacio ◽  
Gwyneth Hughes ◽  
...  

Object Despite its long-reported successful record, with almost 60 years of clinical use, the technical complexity regarding the placement of stereoelectroencephalography (SEEG) depth electrodes may have contributed to the limited widespread application of the technique in centers outside Europe. The authors report on a simplified and novel SEEG surgical technique in the extraoperative mapping of refractory focal epilepsy. Methods The proposed technique was applied in patients with medically refractory focal epilepsy. Data regarding general demographic information, method of electrode implantation, time of implantation, number of implanted electrodes, seizure outcome after SEEG-guided resections, and complications were prospectively collected. Results From March 2009 to April 2012, 122 patients underwent SEEG depth electrode implantation at the Cleveland Clinic Epilepsy Center in which the authors' technique was used. There were 65 male and 57 female patients whose mean age was 33 years (range 5–68 years). The group included 21 pediatric patients (younger than 18 years). Planning and implantations were performed in a single stage. The time for planning was, on average, 33 minutes (range 20–47 minutes), and the time for implantation was, on average, 107 minutes (range 47–150 minutes). Complications related to the SEEG technique were observed in 3 patients. The calculated risk of complications per electrode was 0.18%. The seizure-free rate after SEEG-guided resections was 62% in a mean follow-up period of 12 months. Conclusions The authors report on a safe, simplified, and less time-consuming method of SEEG depth electrode implantation, using standard and widely available surgical tools, making the technique a reasonable option for extraoperative monitoring of patients with medically intractable epilepsy in centers lacking the Talairach stereotactic armamentarium.

2008 ◽  
Vol 25 (3) ◽  
pp. E19 ◽  
Author(s):  
William J. Spire ◽  
Barbara C. Jobst ◽  
Vijay M. Thadani ◽  
Peter D. Williamson ◽  
Terrance M. Darcey ◽  
...  

Object The authors describe their experience with a technique for robotic implantation of depth electrodes in patients concurrently undergoing craniotomy and placement of subdural monitoring electrodes for the evaluation of intractable epilepsy. Methods Patients included in this study underwent evaluation in the Dartmouth Surgical Epilepsy Program and were recommended for invasive seizure monitoring with depth electrodes between 2006 and the present. In all cases an image-guided robotic system was used during craniotomy for concurrent subdural grid electrode placement. A total of 7 electrodes were placed in 4 patients within the time period. Results Three of 4 patients had successful localization of seizure onset, and 2 underwent subsequent resection. Of the patients who underwent resection, 1 is now seizure free, and the second has only auras. There was 1 complication after subpial grid placement but no complications related to the depth electrodes. Conclusions Robotic image-guided placement of depth electrodes with concurrent craniotomy is feasible, and the technique is safe, accurate, and efficient.


Author(s):  
Karl Roessler ◽  
Fabian Winter ◽  
Tobias Wilken ◽  
Ekaterina Pataraia ◽  
Magdalena Mueller-Gerbl ◽  
...  

Abstract Objective Depth electrode implantation for invasive monitoring in epilepsy surgery has become a standard procedure. We describe a new frameless stereotactic intervention using robot-guided laser beam for making precise bone channels for depth electrode placement. Methods A laboratory investigation on a head cadaver specimen was performed using a CT scan planning of depth electrodes in various positions. Precise bone channels were made by a navigated robot-driven laser beam (erbium:yttrium aluminum garnet [Er:YAG], 2.94-μm wavelength,) instead of twist drill holes. Entry point and target point precision was calculated using postimplantation CT scans and comparison to the preoperative trajectory plan. Results Frontal, parietal, and occipital bone channels for bolt implantation were made. The occipital bone channel had an angulation of more than 60 degrees to the surface. Bolts and depth electrodes were implanted solely guided by the trajectory given by the precise bone channels. The mean depth electrode length was 45.5 mm. Entry point deviation was 0.73 mm (±0.66 mm SD) and target point deviation was 2.0 mm (±0.64 mm SD). Bone channel laser time was ∼30 seconds per channel. Altogether, the implantation time was ∼10 to 15 minutes per electrode. Conclusion Navigated robot-assisted laser for making precise bone channels for depth electrode implantation in epilepsy surgery is a promising new, exact and straightforward implantation technique and may have many advantages over twist drill hole implantation.


Neurosurgery ◽  
2015 ◽  
Vol 77 (4) ◽  
pp. 517-524 ◽  
Author(s):  
Aria Fallah ◽  
Shaun D. Rodgers ◽  
Alexander G. Weil ◽  
Sumeet Vadera ◽  
Alireza Mansouri ◽  
...  

Abstract BACKGROUND: There are no established variables that predict the success of curative resective epilepsy surgery in children with tuberous sclerosis complex (TSC). OBJECTIVE: We performed a multicenter observational study to identify preoperative factors associated with seizure outcome in children with TSC undergoing resective epilepsy surgery. METHODS: A retrospective chart review was performed in eligible children at New York Medical Center, Miami Children's Hospital, Cleveland Clinic Foundation, BC Children's Hospital, Hospital for Sick Children, and Sainte-Justine Hospital between January 2005 and December 2013. A time-to-event analysis was performed. The “event” was defined as seizures after resective epilepsy surgery. RESULTS: Seventy-four patients (41 male) were included. The median age of the patients at the time of surgery was 120 months (range, 3-216 months). The median time to seizure recurrence was 24.0 ± 12.7 months. Engel Class I outcome was achieved in 48 (65%) and 37 (50%) patients at 1- and 2-year follow-up, respectively. On univariate analyses, younger age at seizure onset (hazard ratio [HR]: 2.03, 95% confidence interval [CI]: 1.03-4.00, P = .04), larger size of predominant tuber (HR: 1.03, 95% CI: 0.99-1.06, P = .12), and resection larger than a tuberectomy (HR: 1.86, 95% CI: 0.92-3.74, P = .084) were associated with a longer duration of seizure freedom. In multivariate analyses, resection larger than a tuberectomy (HR: 2.90, 95% CI: 1.17-7.18, P = .022) was independently associated with a longer duration of seizure freedom. CONCLUSION: In this large consecutive cohort of children with TSC and medically intractable epilepsy, a greater extent of resection (more than just the tuber) is associated with a greater probability of seizure freedom. This suggests that the epileptogenic zone may include the cortex surrounding the presumed offending tuber.


2010 ◽  
Vol 113 (1) ◽  
pp. 32-38 ◽  
Author(s):  
Jamie J. Van Gompel ◽  
Fredric B. Meyer ◽  
W. Richard Marsh ◽  
Kendall H. Lee ◽  
Gregory A. Worrell

Object Intracranial monitoring for temporal lobe seizure localization to differentiate neocortical from mesial temporal onset seizures requires both neocortical subdural grids and hippocampal depth electrode implantation. There are 2 basic techniques for hippocampal depth electrode implantation. This first technique uses a stereotactically guided 8-contact depth electrode directed along the long axis of the hippocampus to the amygdala via an occipital bur hole. The second technique involves direct placement of 2 or 3 4-contact depth electrodes perpendicular to the temporal lobe through the middle temporal gyrus and overlying subdural grid. The purpose of this study was to determine whether one technique was superior to the other by examining monitoring success and complications. Methods Between 1997 and 2005, 41 patients underwent invasive seizure monitoring with both temporal subdural grids and depth electrodes placed in 2 ways. Patients in Group A underwent the first technique, and patients in Group B underwent the second technique. Results Group A consisted of 26 patients and Group B 15 patients. There were no statistically significant differences between Groups A and B regarding demographics, monitoring duration, seizure localization, or outcome (Engel classification). There was a statistically significant difference at the point in time at which these techniques were used: Group A represented more patients earlier in the series than Group B (p < 0.05). The complication rate attributable to the grids and depth electrodes was 0% in each group. It was more likely that the depth electrodes were placed through the grid if there was a prior resection and the patient was undergoing a new evaluation (p < 0.05). Furthermore, Group A procedures took significantly longer than Group B procedures. Conclusions In this patient series, there was no difference in efficacy of monitoring, complications, or outcome between hippocampal depth electrodes placed laterally through temporal grids or using an occipital bur hole stereotactic approach. Placement of the depth electrodes perpendicularly through the grids and middle temporal gyrus is technically more practical because multiple head positions and redraping are unnecessary, resulting in shorter operative times with comparable results.


Author(s):  
T.M. Peters ◽  
André Olivier

SUMMARY:We describe a computer program which facilitates the analysis of a series of C.T. scans made while a stereotaxic frame is fixed to the patient.The program has 2 modes of operation:a) The operator may select a region and determine the three-dimensional frame coordinate.b) The operator may select a set of frame coordinates and have the computer program display these at the appropriate sites on the C.T. scans. If these sites are the positions of depth electrodes, then a recording of the epileptic spike activity may be displayed at the appropriate sites on the scans.


Neurosurgery ◽  
2015 ◽  
Vol 78 (2) ◽  
pp. 169-180 ◽  
Author(s):  
Jorge González-Martínez ◽  
Juan Bulacio ◽  
Susan Thompson ◽  
John Gale ◽  
Saksith Smithason ◽  
...  

ABSTRACT BACKGROUND: Robot-assisted stereoelectroencephalography (SEEG) may represent a simplified, precise, and safe alternative to the more traditional SEEG techniques. OBJECTIVE: To report our clinical experience with robotic SEEG implantation and to define its utility in the management of patients with medically refractory epilepsy. METHODS: The prospective observational analyses included all patients with medically refractory focal epilepsy who underwent robot-assisted stereotactic placement of depth electrodes for extraoperative brain monitoring between November 2009 and May 2013. Technical nuances of the robotic implantation technique are presented, as well as an analysis of demographics, time of planning and procedure, seizure outcome, in vivo accuracy, and procedure-related complications. RESULTS: One hundred patients underwent 101 robot-assisted SEEG procedures. Their mean age was 33.2 years. In total, 1245 depth electrodes were implanted. On average, 12.5 electrodes were implanted per patient. The time of implantation planning was 30 minutes on average (range, 15-60 minutes). The average operative time was 130 minutes (range, 45-160 minutes). In vivo accuracy (calculated in 500 trajectories) demonstrated a median entry point error of 1.2 mm (interquartile range, 0.78-1.83 mm) and a median target point error of 1.7 mm (interquartile range, 1.20-2.30 mm). Of the group of patients who underwent resective surgery (68 patients), 45 (66.2%) gained seizure freedom status. Mean follow-up was 18 months. The total complication rate was 4%. CONCLUSION: The robotic SEEG technique and method were demonstrated to be safe, accurate, and efficient in anatomically defining the epileptogenic zone and subsequently promoting sustained seizure freedom status in patients with difficult-to-localize seizures.


2012 ◽  
Vol 10 (6) ◽  
pp. 525-528 ◽  
Author(s):  
Stéphane Derrey ◽  
Axel Lebas ◽  
Dominique Parain ◽  
Marie Gilles Baray ◽  
Christophe Marguet ◽  
...  

Intracranial bleeding following stereoelectroencephalography (sEEG) is rare and commonly occurs early after electrode implantation. The authors report the case of a delayed intracranial hematoma following sEEG. This 10-year-old boy was referred to the authors' department to undergo an sEEG study for intractable epilepsy, with the hypothesis of a single localized epileptic zone in the left precentral region. To perform the exploration, 14 depth electrodes were implanted under stereotactic conditions. The results of a postoperative CT scan performed routinely at the end of the surgical procedure were normal. Eight days later, following an epileptic seizure, the child's condition worsened. The neurological examination revealed a left hemiparesis, agitation, and coma due to a right subdural hematoma with intraparenchymal bleeding. Despite a surgical evacuation followed by a decompressive craniectomy, the curative treatments were stopped 1 week later due to severe diffuse ischemic lesions found on MRI studies. This is the first observation of a delayed hematoma following an sEEG procedure. The mechanism underlying this complication remains unclear, but the rupture of a growing pseudoaneurysm caused by the electrode's implantation or the tearing of a neighboring vessel by an electrode were suspected. In consequence, physicians must remain vigilant during the entire sEEG recording period and probably also several days after electrode removal.


2018 ◽  
Vol 128 (4) ◽  
pp. 1147-1157 ◽  
Author(s):  
Soha Alomar ◽  
Jeffrey P. Mullin ◽  
Saksith Smithason ◽  
Jorge Gonzalez-Martinez

OBJECTIVEInsular epilepsy is relatively rare; however, exploring the insular cortex when preoperative workup raises the suspicion of insular epilepsy is of paramount importance for accurate localization of the epileptogenic zone and achievement of seizure freedom. The authors review their clinical experience with stereoelectroencephalography (SEEG) electrode implantation in patients with medically intractable epilepsy and suspected insular involvement.METHODSA total of 198 consecutive cases in which patients underwent SEEG implantation with a total of 1556 electrodes between June 2009 and April 2013 were reviewed. The authors identified patients with suspected insular involvement based on seizure semiology, scalp EEG data, and preoperative imaging (MRI, PET, and SPECT or magnetoencephalography [MEG]). Patients with at least 1 insular electrode based on the postoperative 3D reconstruction of CT fused with the preoperative MRI were included.RESULTSOne hundred thirty-five patients with suspected insular epilepsy underwent insular implantation of a total of 303 electrodes (1–6 insular electrodes per patient) with a total of 562 contacts. Two hundred sixty-eight electrodes (88.5%) were implanted orthogonally through the frontoparietal or temporal operculum (420 contacts). Thirty-five electrodes (11.5%) were implanted by means of an oblique trajectory either through a frontal or a parietal entry point (142 contacts). Nineteen patients (14.07%) had insular electrodes placed bilaterally. Twenty-three patients (17.04% of the insular implantation group and 11.6% of the whole SEEG cohort) were confirmed by SEEG to have ictal onset zones in the insula. None of the patients experienced any intracerebral hemorrhage related to the insular electrodes. After insular resection, 5 patients (33.3%) had Engel Class I outcomes, 6 patients (40%) had Engel Class II, 3 patients (20%) had Engel Class III, and 1 patient (6.66%) had Engel Class IV.CONCLUSIONSInsula exploration with stereotactically placed depth electrodes is a safe technique. Orthogonal electrodes are implanted when the hypothesis suggests opercular involvement; however, oblique electrodes allow a higher insular sampling rate.


2008 ◽  
Vol 25 (3) ◽  
pp. E20 ◽  
Author(s):  
R. Morgan Stuart ◽  
Robert R. Goodman

The authors describe the first reported application of a miniature, customized, one-time use, skull-mounted stereotactic frame for the implantation of depth electrodes for epilepsy monitoring. Using a platform template, 4 skull fiducial markers were placed 1 week prior to surgery. A brain MR image and a CT scan were subsequently obtained. All planning (longitudinal trajectories into the hippocampi) was done preoperatively using personal computers in the office. No further workstation planning was necessary on the day of the operation. The StarFix microTargeting Platform system was secured to the previously implanted skull fiducial screws. Pin fixation was not required. The platform was used to identify the area of entry for the depth electrodes on the right and left sides. On each side, a 12-contact depth electrode was advanced to the depth of the targets without difficulty. A temporal craniotomy was then performed to place subdural electrodes. The desired location of the electrodes was confirmed on postoperative imaging studies. There were no complications associated with the electrode implantation. The depth electrodes demonstrated symmetrical, robust coverage of each hippocampus, with epileptiform discharges observed bilaterally. This first application of the StarFix platform for placing depth electrodes for epilepsy monitoring was both safe and feasible. With this technique, the patient does not need to be pinned or placed in a head holder, no imaging or computer planning is required on the day of implantation (which means there is no time pressure when the meticulous target/trajectory planning is done), and with bilateral posterior implants both bur holes can be made simultaneously. For these reasons this system may be preferable to existing methods of depth electrode implantation.


2018 ◽  
Vol 128 (4) ◽  
pp. 1178-1186 ◽  
Author(s):  
Daniel Delev ◽  
Carlos M. Quesada ◽  
Alexander Grote ◽  
Jan P. Boström ◽  
Christian Elger ◽  
...  

OBJECTIVEDiagnosis and surgical treatment of refractory and apparent nonlesional focal epilepsy is challenging. Morphometric MRI voxel-based and other postprocessing methods can help to localize the epileptogenic zone and thereby support the planning of further invasive electroencephalography (EEG) diagnostics, and maybe resective epilepsy surgery.METHODSThe authors developed an algorithm to implement regions of interest (ROI), based on postprocessed MRI data, into a neuronavigation tool. This was followed by stereotactic ROI-guided implantation of depth electrodes and ROI-navigated resective surgery. Data on diagnostic yield, histology, and seizure outcome were collected and evaluated.RESULTSFourteen consecutive patients with apparently nonlesional epilepsy were included in this study. Reevaluation of the MR images with the help of MRI postprocessing analysis led to the identification of probable subtle lesions in 11 patients. Additional information obtained by SPECT imaging and MRI reevaluation suggested possible lesions in the remaining 3 patients. The ROI-guided invasive implantation of EEG yielded interictal and ictal activity in 13 patients who were consequently referred to resective surgery. Despite the apparently negative MRI findings, focal cortical dysplasia was found in 64% of the patients (n = 9). At the last available outcome, 8 patients (57%) were completely seizure free (International League Against Epilepsy Class 1).CONCLUSIONSThe results demonstrate the feasibility and usefulness of a robust and straightforward algorithm for implementation of MRI postprocessing-based targets into the neuronavigation system. This approach allowed the stereotactic implantation of a low number of depth electrodes only, which confirmed the seizure-onset hypothesis in 90% of the cases without causing any complications. Furthermore, the neuronavigated ROI-guided lesionectomy helped to perform resective surgery in this rather challenging subgroup of patients with apparent nonlesional epilepsy.


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