Novel use of a custom stereotactic frame for placement of depth electrodes for epilepsy monitoring

2008 ◽  
Vol 25 (3) ◽  
pp. E20 ◽  
Author(s):  
R. Morgan Stuart ◽  
Robert R. Goodman
Keyword(s):  
Time Pressure ◽  
Electrode Implantation ◽  
Epileptiform Discharges ◽  
Depth Electrodes ◽  
Depth Electrode ◽  
Stereotactic Frame ◽  
Pin Fixation ◽  
The Right ◽  
Platform System ◽  
Epilepsy Monitoring

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.

Depth Electrodes: Approaches and Complications

2018 ◽  
pp. 50-62
Author(s):  
Thomas Ostergard ◽  
Jonathan P. Miller
Keyword(s):  
Intracranial Haemorrhage ◽  
Electrode Placement ◽  
Frameless Stereotaxy ◽  
Electrode Implantation ◽  
Depth Electrodes ◽  
Stereotactic Frame ◽  
Electrode Length ◽  
Using Data ◽  
Intracranial Electrode ◽  
Neurosurgical Operation

Depth electrode placement is an invaluable technique in treating patients with refractory epilepsy. Like any neurosurgical operation, planning is the most important phase of the procedure. The seizure focus should first be grossly localized using data from scalp electrodes and seizure semiology. This gross localization will guide placement of invasive electrophysiological hardware. All electrode implantation methods rely on Talairach’s principles of stereotaxis. Traditional electrode implantation is performed with a stereotactic frame. Evolving techniques use frameless stereotaxy or neuroendoscopy for implantation. The most worrisome complication of electrode placement is electrode-associated intracranial haemorrhage. Electrode deviation is a much more common complication, which can be minimized by avoiding extreme insertion angles, minimizing intracranial electrode length, and maximizing entry point accuracy.

Robotic Navigated Laser Craniotomy for Depth Electrode Implantation in Epilepsy Surgery: A Cadaver Lab Study

2020 ◽  
Author(s):  
Karl Roessler ◽  
Fabian Winter ◽  
Tobias Wilken ◽  
Ekaterina Pataraia ◽  
Magdalena Mueller-Gerbl ◽  
...  
Keyword(s):  
Laser Beam ◽  
Epilepsy Surgery ◽  
Entry Point ◽  
Occipital Bone ◽  
Electrode Placement ◽  
Target Point ◽  
Twist Drill ◽  
Electrode Implantation ◽  
Depth Electrodes ◽  
Depth Electrode

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.

scholarly journals Stereotactic electroencephalography with temporal grid and mesial temporal depth electrode coverage: does technique of depth electrode placement affect outcome?

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
Keyword(s):  
Temporal Lobe ◽  
Middle Temporal Gyrus ◽  
Electrode Implantation ◽  
Middle Temporal ◽  
Contact Depth ◽  
Depth Electrodes ◽  
Depth Electrode ◽  
Group A ◽  
Group B ◽  
Seizure Localization

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.

scholarly journals C.T. Aided Stereotaxy for Depth Electrode Implantation and Biopsy

1983 ◽  
Vol 10 (3) ◽  
pp. 166-169 ◽  
Author(s):  
T.M. Peters ◽  
André Olivier
Keyword(s):  
Computer Program ◽  
Spike Activity ◽  
Three Dimensional ◽  
Modes Of Operation ◽  
Electrode Implantation ◽  
Depth Electrodes ◽  
Depth Electrode ◽  
Epileptic Spike

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.

Freehand placement of depth electrodes using electromagnetic frameless stereotactic guidance

2011 ◽  
Vol 8 (5) ◽  
pp. 464-467 ◽  
Author(s):  
Carter D. Wray ◽  
Diana L. Kraemer ◽  
Tong Yang ◽  
Sandra L. Poliachik ◽  
Andrew L. Ko ◽  
...  
Keyword(s):  
Electrode Placement ◽  
Frameless Stereotaxy ◽  
Seizure Onset ◽  
Presurgical Evaluation ◽  
Electromagnetic System ◽  
Depth Electrodes ◽  
Depth Electrode ◽  
Stereotactic Frame ◽  
Stereotactic Guidance ◽  
Patients With Epilepsy

The presurgical evaluation of patients with epilepsy often requires an intracranial study in which both subdural grid electrodes and depth electrodes are needed. Performing a craniotomy for grid placement with a stereotactic frame in place can be problematic, especially in young children, leading some surgeons to consider frameless stereotaxy for such surgery. The authors report on the use of a system that uses electromagnetic impulses to track the tip of the depth electrode. Ten pediatric patients with medically refractory focal lobar epilepsy required placement of both subdural grid and intraparenchymal depth electrodes to map seizure onset. Presurgical frameless stereotaxic targeting was performed using a commercially available electromagnetic image-guided system. Freehand depth electrode placement was then performed with intraoperative guidance using an electromagnetic system that provided imaging of the tip of the electrode, something that has not been possible using visually or sonically based systems. Accuracy of placement of depth electrodes within the deep structures of interest was confirmed postoperatively using CT and CT/MR imaging fusion. Depth electrodes were appropriately placed in all patients. Electromagnetic-tracking–based stereotactic targeting improves the accuracy of freehand placement of depth electrodes in patients with medically refractory epilepsy. The ability to track the electrode tip, rather than the electrode tail, is a major feature that enhances accuracy. Additional advantages of electromagnetic frameless guidance are discussed.

Occipitotemporal hippocampal depth electrodes in intracranial epilepsy monitoring: safety and utility

2013 ◽  
Vol 118 (2) ◽  
pp. 345-352 ◽  
Author(s):  
Kimon Bekelis ◽  
Atman Desai ◽  
Alex Kotlyar ◽  
Vijay Thadani ◽  
Barbara C. Jobst ◽  
...  
Keyword(s):  
Hippocampal Formation ◽  
Imaging Techniques ◽  
Drill Hole ◽  
Mesial Temporal Sclerosis ◽  
Depth Electrodes ◽  
Depth Electrode ◽  
Intractable Seizures ◽  
Temporal Lobe Resection ◽  
Temporal Localization ◽  
Epilepsy Monitoring

Object Intracranial monitoring for epilepsy has been proven to enhance diagnostic accuracy and provide localizing information for surgical treatment of intractable seizures. The authors investigated the usefulness of hippocampal depth electrodes in the era of more advanced imaging techniques. Methods Between 1988 and 2010, 100 patients underwent occipitotemporal hippocampal depth electrode (OHDE) implantation as part of invasive seizure monitoring, and their charts were retrospectively reviewed. The authors' technique involved the stereotactically guided (using the Leksell model G frame) implantation of a 12-contact depth electrode directed along the long axis of the hippocampus, through an occipital twist drill hole. Results Of the 100 patients (mean age 35.0 years [range 13–58 years], 51% male) who underwent intracranial investigation, 84 underwent resection of the seizure focus. Magnetic resonance imaging revealed mesial temporal sclerosis (MTS) in 27% of patients, showed abnormal findings without MTS in 55% of patients, and showed normal findings in 18% of patients. One patient developed a small asymptomatic occipital hemorrhage around the electrode tract. The use of OHDEs enabled epilepsy resection in 45.7% of patients who eventually underwent standard or selective temporal lobe resection. The hippocampal formation was spared during surgery because data obtained from the depth electrodes showed no or only secondary involvement in 14% of patients with preoperative temporal localization. The use of OHDEs prevented resections in 12% of patients with radiographic evidence of MTS. Eighty-three percent of patients who underwent resection had Engel Class I (68%) or II (15%) outcome at 2 years of follow-up. Conclusions The use of OHDEs for intracranial epilepsy monitoring has a favorable risk profile, and in the authors' experience it proved to be a valuable component of intracranial investigation. The use of OHDEs can provide the sole evidence for resection of some epileptogenic foci and can also result in hippocampal sparing or prevent likely unsuccessful resection in other patients.

Accuracy of frameless image-guided implantation of depth electrodes for intracranial epilepsy monitoring

2020 ◽  
Vol 132 (3) ◽  
pp. 681-691
Author(s):  
Robert E. Gross ◽  
Edward K. Sung ◽  
Patrick Mulligan ◽  
Nealen G. Laxpati ◽  
Darlene A. Mayo ◽  
...  
Keyword(s):  
Quantitative Analysis ◽  
Temporal Lobe ◽  
Medial Temporal Lobe ◽  
Mr Images ◽  
Seizure Onset ◽  
Electrode Implantation ◽  
Depth Electrodes ◽  
Mri Guided ◽  
Burr Holes ◽  
Epilepsy Monitoring

OBJECTIVEVarious techniques are available for stereotactic implantation of depth electrodes for intracranial epilepsy monitoring. The goal of this study was to evaluate the accuracy and effectiveness of frameless MRI-guided depth electrode implantation.METHODSUsing a frameless MRI-guided stereotactic approach (Stealth), depth electrodes were implanted in patients via burr holes or craniotomy, mostly into the medial temporal lobe. In all cases in which it was possible, postoperative MR images were coregistered to planning MR images containing the marked targets for quantitative analysis of intended versus actual location of each electrode tip. In the subset of MR images done with sufficient resolution, qualitative assessment of anatomical accuracy was performed. Finally, the effectiveness of implanted electrodes for identifying seizure onset was retrospectively examined.RESULTSSixty-eight patients underwent frameless implantation of 413 depth electrodes (96% to mesial temporal structures) via burr holes by one surgeon at 2 institutions. In 36 patients (203 electrodes) planning and postoperative MR images were available for quantitative analysis; an additional 8 procedures with 19 electrodes implanted via craniotomy for grid were also available for quantitative analysis. The median distance between intended target and actual tip location was 5.19 mm (mean 6.19 ± 4.13 mm, range < 2 mm–29.4 mm). Inaccuracy for transtemporal depths was greater along the electrode (i.e., deep), and posterior, whereas electrodes inserted via an occipital entry deviated radially. Failure to localize seizure onset did not result from implantation inaccuracy, although 2 of 62 patients (3.2%)—both with electrodes inserted occipitally—required reoperation. Complications were mostly transient, but resulted in long-term deficit in 2 of 68 patients (3%).CONCLUSIONSDespite modest accuracy, frameless depth electrode implantation was sufficient for seizure localization in the medial temporal lobe when using the orthogonal approach, but may not be adequate for occipital trajectories.

Robotic image-guided depth electrode implantation in the evaluation of medically intractable epilepsy

2008 ◽  
Vol 25 (3) ◽  
pp. E19 ◽  
Author(s):  
William J. Spire ◽  
Barbara C. Jobst ◽  
Vijay M. Thadani ◽  
Peter D. Williamson ◽  
Terrance M. Darcey ◽  
...  
Keyword(s):  
Intractable Epilepsy ◽  
Robotic System ◽  
Electrode Placement ◽  
Seizure Onset ◽  
Electrode Implantation ◽  
Grid Electrode ◽  
Image Guided ◽  
Depth Electrodes ◽  
Depth Electrode ◽  
Time Period

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.

Operative Nuances of Stereotactic Leksell Frame-Based Depth Electrode Implantation

2017 ◽  
Vol 15 (3) ◽  
pp. 292-295 ◽  
Author(s):  
Holger Joswig ◽  
Carolyn M Benson ◽  
Andrew G Parrent ◽  
Keith W MacDougall ◽  
David A Steven
Keyword(s):  
Technical Note ◽  
Implantation Technique ◽  
Electrode Implantation ◽  
Depth Electrodes ◽  
Depth Electrode ◽  
The World

Abstract Background For intracranial electroencephalographic monitoring, stereotactically implanted depth electrodes are increasingly used at epilepsy centers around the world. Objective To identify pearls and pitfalls from our experience with stereotactic Leksell (Elekta AB, Stockhom, Sweden) frame-based depth electrode implantation. Methods An intraoperative video of the implantation technique was recorded. Results A detailed description and a video on how to implant depth electrodes using the stereotactic Leksell frame is provided. Conclusion Neurosurgeons implanting depth electrodes for intracranial electroencephalographic monitoring might find the technical nuances and caveats described in this technical note useful for their practice.

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