Robotic Orthogonal Implantation of Responsive Neurostimulation (RNS) Depth Electrodes in the Mesial Temporal Lobe: Case Series

Abstract BACKGROUND Responsive neurostimulation (RNS) is a closed-loop neurostimulation modality for treating intractable epilepsy in patients who are not candidates for resection. In the past, implantation of depth electrodes was done through a transoccipital approach that transverses the hippocampus. There have been no descriptions of orthogonal approaches to RNS electrode placement. OBJECTIVE To describe our initial experience with placing RNS depth electrodes using an orthogonal approach to target the short axis of the mesial temporal lobe. METHODS Presurgical work-up included magnetic resonance imaging, video electroencephalography, and neuropsychological testing. During the procedure, patients were placed with their heads in a neutral position. Electrodes were placed via stereotactic robotic assistance using a unilateral orthogonal approach targeting the amygdala or hippocampus. Patients who underwent RNS electrode implantation via orthogonal approach were identified. Multiple variables were collected, including age, disease onset, complications, follow-up, semiology, and seizure reduction. RESULTS There were 8 patients who underwent RNS electrode placement with orthogonal approach. The mean age and follow-up were 44.8 and 1.2 yr, respectively. There were 4 patients with at least 1-yr follow-up. Of them, 1 was seizure free and 2 experienced over 50% reduction in seizures. There were no complications associated with electrode implantation. CONCLUSION The initial experience using an orthogonal approach for depth electrode placement for RNS implantation was described. The potential advantages may include better safety, accuracy, and positioning in comparison to a transoccipital approach.

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Robotic Orthogonal Implantation of Responsive Neurostimulation (RNS) Depth Electrodes in Patients With Unilateral Mesial Temporal Lobe Seizure Onset

Neurosurgery ◽

10.1093/neuros/nyz310_426 ◽

2019 ◽

Vol 66 (Supplement_1) ◽

Author(s):

Alvin Y Chan ◽

Sumeet Vadera

Keyword(s):

Temporal Lobe ◽

Disease Onset ◽

Electrode Placement ◽

Neutral Position ◽

Initial Experience ◽

Depth Electrodes ◽

Number Of Patients ◽

Multiple Variables ◽

Mesial Temporal Lobe

Abstract INTRODUCTION Responsive neurostimulation (RNS) is a closed-loop neurostimulation modality for treating intractable epilepsy in patients who are not candidates for resection. A high number of patients have ictal onsets originating in the temporal lobe. In the past, implantation of depth electrodes have been placed using a transoccipital approach that transverses the long axis of the hippocampus. However, there have been no description of orthogonal approaches to RNS electrode placement into the medial temporal structures in the literature. We aimed to describe our initial experience with placing RNS depth electrodes using an orthogonal approach to target the short axis of the mesial temporal lobe. METHODS Presurgical work up included magnetic resonance imaging (MRI), video electroencephalography (vEEG), and neuropsychological testing. During the procedure, patients were placed with their heads in a neutral position. Electrodes were placed via stereotactic robotic assistance using a unilateral orthogonal approach targeting the amygdala or hippocampus. Patients who underwent RNS electrode implantation via orthogonal approach were identified after a retrospective review of all RNS patients at our institution. Multiple variables were collected, including age, disease onset, complications, follow-up, semiology, and seizure reduction. RESULTS There were 4 patients who underwent RNS implantation with orthogonal electrode placement. The mean age and follow-up were 44.8 and 1.2 yr, respectively. One of 8 patients was seizure free at last follow-up and 2 experienced over 50% reduction in seizures. There was one surgical complication but no mortality. CONCLUSION The initial experience using an orthogonal approach for depth electrode placement for RNS implantation was described. The potential advantages may include better safety, accuracy, and positioning in comparison to a transoccipital approach. Limitations included the retrospective nature of the study and a low sample size. Further research and experience are required to determine the best indications for an orthogonal approach.

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Utility of depth electrode placement in the neurosurgical management of bottom-of-sulcus lesions: technical note

Journal of Neurosurgery Pediatrics ◽

10.3171/2019.4.peds18639 ◽

2019 ◽

Vol 24 (3) ◽

pp. 284-292

Author(s):

Eisha A. Christian ◽

Elysa Widjaja ◽

Ayako Ochi ◽

Hiroshi Otsubo ◽

Stephanie Holowka ◽

...

Keyword(s):

Pediatric Patients ◽

Focal Cortical Dysplasia ◽

Target Identification ◽

Cortical Dysplasia ◽

Technical Note ◽

Electrode Placement ◽

Electrode Implantation ◽

Depth Electrodes ◽

Intracranial Electrode ◽

The Brain

OBJECTIVESmall lesions at the depth of the sulcus, such as with bottom-of-sulcus focal cortical dysplasia, are not visible from the surface of the brain and can therefore be technically challenging to resect. In this technical note, the authors describe their method of using depth electrodes as landmarks for the subsequent resection of these exacting lesions.METHODSA retrospective review was performed on pediatric patients who had undergone invasive electroencephalography with depth electrodes that were subsequently used as guides for resection in the period between July 2015 and June 2017.RESULTSTen patients (3–15 years old) met the criteria for this study. At the same time as invasive subdural grid and/or strip insertion, between 2 and 4 depth electrodes were placed using a hand-held frameless neuronavigation technique. Of the total 28 depth electrodes inserted, all were found within the targeted locations on postoperative imaging. There was 1 patient in whom an asymptomatic subarachnoid hemorrhage was demonstrated on postprocedural imaging. Depth electrodes aided in target identification in all 10 cases.CONCLUSIONSDepth electrodes placed at the time of invasive intracranial electrode implantation can be used to help localize, target, and resect primary zones of epileptogenesis caused by bottom-of-sulcus lesions.

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Accuracy and Efficacy for Robotic Assistance in Implanting Responsive Neurostimulation Device Electrodes in Bilateral Mesial Temporal Lobe Epilepsy

Operative Neurosurgery ◽

10.1093/ons/opx085 ◽

2017 ◽

Vol 14 (3) ◽

pp. 267-272 ◽

Cited By ~ 7

Author(s):

Alvin Y Chan ◽

Lilit Mnatsakanyan ◽

Mona Sazgar ◽

Indranil Sen-Gupta ◽

Jack J Lin ◽

...

Keyword(s):

Temporal Lobe Epilepsy ◽

Temporal Lobe ◽

Focal Epilepsy ◽

Mesial Temporal Lobe Epilepsy ◽

Advanced Technology ◽

Robotic Assistance ◽

Mesial Temporal Lobe ◽

Robotic Devices ◽

New Treatment

Abstract BACKGROUND Responsive neurostimulation (RNS) is a relatively new treatment option that has been shown to be effective for patients with medically refractory focal epilepsy when resection is not possible, especially in bilateral mesial temporal onset. Robotic devices are becoming increasingly popular for use in stereotactic procedures such as stereoelectroencephalography, but have yet to be used when implanting RNS devices. OBJECTIVE To show that these 2 forms of advanced technology were compatible and could be used effectively in patient care. METHODS We implanted RNS devices in 3 patients with bilateral mesial temporal lobe epilepsy. Each patient was placed in the prone position, and electrode trajectories were planned via the robotic navigation system via a transoccipital approach. One lead was placed along each amygdalohippocampal complex. A small craniectomy was then created in the parietal region for RNS generator implantation. Actual and expected target locations and distance were calculated for each depth. There were no complications in this group. RESULTS RNS devices with bilateral leads were successfully implanted in all 3 patients, with bilateral mesial temporal lobe onset. Follow-up ranged from 3 to 6 mo, and there were no complications in this group. The median distance between the estimate and actual targets was 2.18 (range = 1.11-3.27) mm. CONCLUSION We show that implanting RNS devices with robotic assistance is feasible with excellent precision and accuracy. The advantages of using robotic assistance include higher flexibility, accuracy, precision, and consistency.

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Surgical Outcomes and EEG Prognostic Factors After Stereotactic Laser Amygdalohippocampectomy for Mesial Temporal Lobe Epilepsy

Frontiers in Neurology ◽

10.3389/fneur.2021.654668 ◽

2021 ◽

Vol 12 ◽

Author(s):

Shasha Wu ◽

Naoum P. Issa ◽

Maureen Lacy ◽

David Satzer ◽

Sandra L. Rose ◽

...

Keyword(s):

Temporal Lobe Epilepsy ◽

Temporal Lobe ◽

Surgical Outcomes ◽

Mesial Temporal Lobe Epilepsy ◽

Seizure Freedom ◽

Seizure Recurrence ◽

Factors Associated ◽

Scalp Eeg ◽

Mesial Temporal Lobe

Objective: To assess the seizure outcomes of stereotactic laser amygdalohippocampectomy (SLAH) in consecutive patients with mesial temporal lobe epilepsy (mTLE) in a single center and identify scalp EEG and imaging factors in the presurgical evaluation that correlate with post-surgical seizure recurrence.Methods: We retrospectively reviewed the medical and EEG records of 30 patients with drug-resistant mTLE who underwent SLAH and had at least 1 year of follow-up. Surgical outcomes were classified using the Engel scale. Univariate hazard ratios were used to evaluate the risk factors associated with seizure recurrence after SLAH.Results: The overall Engel class I outcome after SLAH was 13/30 (43%), with a mean postoperative follow-up of 48.9 ± 17.6 months. Scalp EEG findings of interictal regional slow activity (IRSA) on the side of surgery (HR = 4.05, p = 0.005) and non-lateralizing or contra-lateralizing seizure onset (HR = 4.31, p = 0.006) were negatively correlated with postsurgical seizure freedom. Scalp EEG with either one of the above features strongly predicted seizure recurrence after surgery (HR = 7.13, p < 0.001) with 100% sensitivity and 71% specificity.Significance: Understanding the factors associated with good or poor surgical outcomes can help choose the best candidates for SLAH. Of the variables assessed, scalp EEG findings were the most clearly associated with seizure outcomes after SLAH.

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Depth Electrodes: Approaches and Complications

Invasive Studies of the Human Epileptic Brain ◽

10.1093/med/9780198714668.003.0005 ◽

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.

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

Journal of Neurological Surgery Part A Central European Neurosurgery ◽

10.1055/s-0040-1720998 ◽

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.

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Stereotactic-EEG Guided Radiofrequency Thermocoagulation Versus Anterior Temporal Lobectomy for Mesial Temporal Lobe Epilepsy with Hippocampal Sclerosis: Study protocol for a randomized controlled trial

10.21203/rs.3.rs-56665/v1 ◽

2021 ◽

Author(s):

Yi-He Wang ◽

Si-Chang Chen ◽

Peng-Hu Wei ◽

Kun Yang ◽

Xiao-Tong Fan ◽

...

Keyword(s):

Temporal Lobe Epilepsy ◽

Temporal Lobe ◽

Hippocampal Sclerosis ◽

Controlled Trial ◽

Mesial Temporal Lobe Epilepsy ◽

Temporal Lobectomy ◽

Anterior Temporal Lobectomy ◽

Radiofrequency Thermocoagulation ◽

Mesial Temporal Lobe

Abstract Introduction: In this report, we aim to describe the design for the randomized controlled trial of Stereotactic-electroencephalogram (EEG) guided Radiofrequency Thermocoagulation versus Anterior Temporal Lobectomy for Mesial Temporal Lobe Epilepsy with Hippocampal Sclerosis (STARTS). Mesial temporal lobe epilepsy (mTLE) is a classical subtype of temporal lobe epilepsy that often requires surgical intervention. Although anterior temporal lobectomy (ATL) remains the most popular treatment for mTLE, accumulating evidence has indicated that ATL can cause tetartanopia and memory impairments. Stereotactic EEG (SEEG)-guided radiofrequency thermocoagulation (RF-TC) is a non-invasive alternative associated with lower seizure freedom but greater preservation of neurological function. In the present study, we aim to compare the safety and efficacy of SEEG-guided RF-TC and classical ATL in the treatment of mTLE. Methods and analysis: STARTS is a single-centre, two-arm, randomised controlled, parallel-group clinical trial. The study includes patients with typical mTLE over the age of 14 who have drug-resistant seizures for at least 2 years and have been determined via detailed evaluation to be surgical candidates prior to randomisation. The primary outcome measure is cognitive function at the 1-year follow-up after treatment. Seizure outcomes, visual field abnormalities after surgery, quality of life, ancillary outcomes, and adverse events will also be evaluated at 1-year follow-up as secondary outcomes. Disscussion: SEEG-guided RF-TC for mTLE remains a controversial seizure outcome but has the advantage for cognitive and visual filed protection. This is the first RCT studying cognitive outcomes and treatment results between SEEG-guided RF-TC and standard ATL for mTLE with hippocampal sclerosis. This study may provide a higher levels of clinical evidence for the treatment for mTLE. Trial registration: The STARTS protocol has been registered on the US National Institutes of Health (ClinicalTrials.gov): NCT03941613. The status of the STARTS was recruiting and the estimated study completion date was December 31, 2021.

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

Journal of Neurosurgery ◽

10.3171/2009.12.jns091073 ◽

2010 ◽

Vol 113 (1) ◽

pp. 32-38 ◽

Cited By ~ 23

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.

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Gamma Knife radiosurgery for recurrent or residual seizures after anterior temporal lobectomy in mesial temporal lobe epilepsy patients with hippocampal sclerosis: long-term follow-up results of more than 4 years

Journal of Neurosurgery ◽

10.3171/2014.12.jns141280 ◽

2015 ◽

Vol 123 (6) ◽

pp. 1375-1382 ◽

Cited By ~ 4

Author(s):

Eun Mi Lee ◽

Joong Koo Kang ◽

Sang Joon Kim ◽

Seok Ho Hong ◽

Tae Sung Ko ◽

...

Keyword(s):

Temporal Lobe ◽

Hippocampal Sclerosis ◽

Gamma Knife Radiosurgery ◽

Mesial Temporal Lobe Epilepsy ◽

Temporal Lobectomy ◽

Seizure Outcome ◽

Anterior Temporal Lobectomy ◽

Mesial Temporal Lobe ◽

Signal Changes

OBJECTGamma Knife radiosurgery (GKRS) has proven efficacy in the treatment of drug-resistant mesial temporal lobe epilepsy with hippocampal sclerosis (MTLE-HS) and is comparable to conventional resective surgery. It may be effective as an alternative treatment to reoperation after failed temporal lobe surgery in patients with MTLE-HS. The purpose of this study was to investigate the efficacy of GKRS in patients with unilateral MTLE-HS who did not achieve seizure control or had recurrent seizures after anterior temporal lobectomy (ATL).METHODSTwelve patients (8 males; mean age 35.50 ± 9.90 years) with MTLE-HS who underwent GKRS after failed ATL (Engel Classes III–IV) were included. GKRS targets included the remnant tissue or adjacent regions of the previously performed ATL with a marginal dose of 24–25 Gy at the 50% isodose line in all patients. Final seizure outcome was assessed using Engel’s modified criteria during the final 2 years preceding data analysis. A comparison between signal changes on follow-up MRI and clinical outcome was performed.RESULTSAll patients were followed up for at least 4 years with a mean duration of 6.18 ± 1.77 years (range 4–8.8 years) after GKRS. At the final assessment, 6 of 12 patients were classified as seizure free (Engel Class Ia, n = 3; Ic, n = 2; and Id, n = 1) and 6 patients were classified as not seizure free (Engel Class II, n = 1; III, n = 2; and IV, n = 3). Neither initial nor late MRI signal changes after GKRS statistically correlated with surgical outcome. Clinical seizure outcome did not differ significantly with initial or late MRI changes after GKRS.CONCLUSIONSGKRS can be considered an alternative option when the patients with MTLE-HS who had recurrent or residual seizures after ATL refuse a second operation.

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Electrical Stimulation of Subiculum for the Treatment of Refractory Mesial Temporal Lobe Epilepsy with Hippocampal Sclerosis: A 2-Year Follow-Up Study

Stereotactic and Functional Neurosurgery ◽

10.1159/000510295 ◽

2020 ◽

pp. 1-8

Author(s):

Daruni Vázquez-Barrón ◽

Manola Cuéllar-Herrera ◽

Francisco Velasco ◽

Ana Luisa Velasco

Keyword(s):

Electrical Stimulation ◽

Temporal Lobe Epilepsy ◽

Temporal Lobe ◽

Hippocampal Sclerosis ◽

Mesial Temporal Lobe Epilepsy ◽

Open Label ◽

Anticonvulsive Effect ◽

Mesial Temporal Lobe ◽

Stimulation Of

Introduction: Evidence has been provided that the subiculum may play an important role in the generation of seizures. Electrical stimulation at this target has been reported to have anticonvulsive effects in kindling and pilocarpine rat models, while in a clinical study of hippocampal deep brain stimulation (DBS), contacts closest to the subiculum were associated with a better anticonvulsive effect. Objectives: To evaluate the effect of electrical stimulation of the subiculum in patients with refractory mesial temporal lobe epilepsy (MTLE) who have hippocampal sclerosis (HS). Methods: Six patients with refractory MTLE and HS, who had focal impaired awareness seizures (FIAS) and focal to bilateral tonic-clonic seizures (FBTCS), had DBS electrodes implanted in the subiculum. During the first month after implantation, all patients were OFF stimulation, then they all completed an open-label follow-up of 24 months ON stimulation. DBS parameters were set at 3 V, 450 µs, 130 Hz, cycling stimulation 1 min ON, 4 min OFF. Results: There was a mean reduction of 49.16% (±SD 41.65) in total seizure number (FIAS + FBTCS) and a mean reduction of 67.93% (±SD 33.33) in FBTCS at 24 months. FBTCS decreased significantly with respect to baseline, starting from month 2 ON stimulation. Conclusions: Subiculum stimulation is effective for FBTCS reduction in patients with MTLE and HS, suggesting that the subiculum mediates the generalization rather than the genesis of mesial temporal lobe seizures. Better results are observed at longer follow-up times.

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