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Methodology of electrode implantations. A and B: Planning of electrode trajectories using navigation software. C: Coordinates of the Leksell frame are set by the operating neurosurgeon. D: Introduction of the stylet through the guiding screw to a premeasured length to create the electrode tract. E: Insertion of the depth electrode through the screw. F: Aspect at the end of the procedure, after implantation of 13 depth electrodes and placement of fixation bolts
Source publication
Background:
Stereoelectroencephalography (SEEG) is an established diagnostic technique for the localization of the epileptogenic zone in drug-resistant epilepsy. In vivo accuracy of SEEG electrode positioning is of paramount importance since higher accuracy may lead to more precise resective surgery, better seizure outcome and reduction of complic...
Similar publications
The localization of the epileptogenic zone (EZ) is crucial for the successful surgical treatment of epileptic patients who suffer from drug-resistant epilepsy. In this paper, we propose a new approach for EZ localization. The partial directed coherence approach and the outstrength parameter derived from graph theory are used to characterize the syn...
Citations
... Deviation of the electrode insertion trajectory from the planned trajectory may result in damage to vessels and tissues and hence major complications (25), whereas deviation of the electrode tip position from the planned target position leads to incomplete lesion tissue ablation and unsatisfactory postoperative epilepsy relief effects. There are some articles on the in vivo accuracy of SEEG for presurgical investigation (17)(18)(19)(20)(26)(27)(28)(29), but to the best of our knowledge, no studies of the accuracy of SEEG for treatment of pediatric HH have been published. Compared with adults, children have a thinner and more fragile skull, and young children have patent skull sutures, which may affect the accuracy of electrode implantation (26,28). ...
... We reported a median target point error of 2.74 mm. Van der Loo et al. (29) reported the largest SEEG implantation error of the Talairach framework system to date. Specifically, 866 electrodes were implanted in 76 operations, and the median Euclidean distance target error was 2.93 mm. ...
... The underlying reason is unclear. It may be due to (i) the fact that the electrodes in our study were significantly longer than those of other studies of only preoperative (27,29) or (ii) the age of patients which median is 3.8 years, the skull is thinner than in adults, and some children have patent cranial sutures. ...
Objective
We aimed to investigate the methodology, results, complications and stereotactic application accuracy of electrode implantation and its explanatory variables in stereoelectroencephalography-guided radiofrequency thermocoagulation (SEEG-RFTC) for pediatric hypothalamic hamartoma.
Methods
Children with hypothalamic hamartoma who underwent robot-assisted SEEG-RFTC between December 2017 and November 2021 were retrospectively analyzed. The methodology, seizure outcome, complications, in vivo accuracy of electrode implantation and its explanatory variables were analyzed.
Results
A total of 161 electrodes were implanted in 28 patients with 30 surgeries. Nine electrodes not following the planned trajectories due to intraoperative replanning were excluded, and the entry point and target point errors of 152 electrodes were statistically analyzed. The median entry point error was 0.87 mm (interquartile range, 0.50–1.41 mm), and the median target point error was 2.74 mm (interquartile range, 2.01–3.63 mm). Multifactor analysis showed that whether the electrode was bent (b = 2.16, p < 0.001), the length of the intracranial electrode (b = 0.02, p = 0.049), and the entry point error (b = 0.337, p = 0.017) had statistically significant effects on the target error. During follow-up (mean duration 31 months), 27 of 30 (90%) procedures were seizure-free. The implantation-related complication rate was 2.6% (4/152), and the major complication rate in all procedures was 6.7% (2/30).
Conclusion
Robot-assisted SEEG-RFTC is a safe, effective and accurate procedure for pediatric hypothalamic hamartoma. Explanatory variables significantly associated with the target point localization error at multivariate analysis include whether the intracranial electrode is bent, the intracranial electrode length and the entry point error.
... An oblique trajectory along the hippocampal axis with an occipital entry point avoids such conflicts [14,15]. This approach, however, is prone to imprecision due to its angularity and length increasing the risk of vascular injury [16,17]. Furthermore, additional electrodes are needed for full SEEG coverage of the lateral temporal lobe [18,19]. ...
Objective:
Invasive video-electroencephalography (iVEEG) is the gold standard for evaluation of refractory temporal lobe epilepsy before second stage resective surgery (SSRS). Traditionally, the presumed seizure onset zone (SOZ) has been covered with subdural electrodes (SDE), a very invasive procedure prone to complications. Temporal stereoelectroencephalography (SEEG) with conventional frame-based stereotaxy is time-consuming and impeded by the geometry of the frame. The introduction of robotic assistance promised a simplification of temporal SEEG implantation. However, the efficacy of temporal SEEG in iVEEG remains unclear. The aim of the present study was therefore to describe the efficiency and efficacy of SEEG in iVEEG of temporal lobe epilepsy.
Methods:
This retrospective study enrolled 60 consecutive patients with medically intractable epilepsy who underwent iVEEG of a potential temporal SOZ by SDE (n=40) or SEEG (n=20). Surgical time efficiency was analyzed by the skin-to-skin time (STS) and the total procedure time (TPT) and compared between groups (SDE vs. SEEG). Surgical risk was depicted by the 90-day complication rate. Temporal SOZ were treated by second stage resective surgery (SSRS). Favorable outcome (Engel°1) was assessed after one year of follow-up.
Results:
Robot-assisted SEEG significantly reduced the duration of surgery (STS and TPT) compared to SDE implantations. There was no significant difference in complication rates. Notably, all surgical revisions in this study were attributed to SDE. Unilateral temporal SOZ was detected in 34/60 cases. 30/34 patients underwent second stage SSRS. Both SDE and SEEG had a good predictive value for the outcome of temporal SSRS with no significant group difference.
Significance:
Robot-assisted SEEG improves the accessibility of the temporal lobe for iVEEG by increasing surgical time efficiency and by simplifying trajectory selection without losing its predictive value for SSRS.
... However, all contacts of the electrode play an important role in SEEG monitoring. The multimodal factors influencing final accuracy in the individual patient have rarely been studied [16]- [18] because final electrode placement, i.e., individual contacts visible in computed tomography images (CT), is challenging to parametrize exactly. Although individual contacts can be labeled manually, this process is extremely time-consuming and requires experience with electrode imagination in a threedimensional (3D) space. ...
... The positions of implanted electrodes are usually imprecise with respect to planned trajectories, slightly wavy, and sometimes curved [15], [16], [30], [31] (Fig. 3A). Therefore, attributes of electrodes (TG, ⃗ ⃗ , label name, number of contacts) could not be correctly assigned to appropriate metal voxels (platinum, > 3000 [19]). ...
... p < 0.001) between the implantation angle and bone thickness reflects more perpendicular implantation of temporal structures for naturally thinner bone. The correlation of bone thickness with entry point erorr (C = 0.19, p < 0.001) reflects more difficult drilling control from the superior oblique direction [16]. Similarly, long electrodes (frontal, insular) usually entered under a low implantation angle (C = −0.20, ...
Objective: Stereoelectroencephalography (SEEG) is an established invasive diagnostic technique for use in patients with drug-resistant focal epilepsy evaluated before resective epilepsy surgery. The factors that influence the accuracy of electrode implantation are not fully understood. Adequate accuracy prevents the risk of major surgery complications. Precise knowledge of the anatomical positions of individual electrode contacts is crucial for the interpretation of SEEG recordings and subsequent surgery. Methods: We developed an image processing pipeline to localize implanted electrodes and detect individual contact positions using computed tomography (CT), as a substitute for time-consuming manual labeling. The algorithm automates measurement of parameters of the electrodes implanted in the skull (bone thickness, implantation angle and depth) for use in modeling of predictive factors that influence implantation accuracy. Results: Fifty-four patients evaluated by SEEG were analyzed. A total of 662 SEEG electrodes with 8,745 contacts were stereotactically inserted. The automated detector localized all contacts with better accuracy than manual labeling (p < 0.001). The retrospective implantation accuracy of the target point was 2.4 ± 1.1 mm. A multifactorial analysis determined that almost 58% of the total error was attributable to measurable factors. The remaining 42% was attributable to random error. Conclusion: SEEG contacts can be reliably marked by our proposed method. The trajectory of electrodes can be parametrically analyzed to predict and validate implantation accuracy using a multifactorial model.
Significance: This novel, automated image processing technique is a potentially clinically important, assistive tool for increasing the yield, efficiency, and safety of SEEG.</p
... These electrodes require a large craniotomy. In the monitoring of epilepsy patients, in which almost all of the previous studies have been conducted, more and more centers utilize the less invasive stereotactic EEG (sEEG), which is measured with intracranial depth electrodes [22]. The use of sEEG for BCI has been discussed before [23] and successfully applied to word decoding [24] and speech synthesis [25]. ...
Speech Neuroprostheses have the potential to enable communication for people with dysarthria or anarthria. Recent advances have demonstrated high-quality text decoding and speech synthesis from electrocorticographic grids placed on the cortical surface. Here, we investigate a less invasive measurement modality in three participants, namely stereotactic EEG (sEEG) that provides sparse sampling from multiple brain regions, including subcortical regions. To evaluate whether sEEG can also be used to synthesize high-quality audio from neural recordings, we employ a recurrent encoder-decoder model based on modern deep learning methods. We find that speech can indeed be reconstructed with correlations up to 0.8 from these minimally invasive recordings, despite limited amounts of training data.
... According to our analysis, skull thickness is positively correlated with TP error. This result has been reported by Sharma et al. [38] and Lars E et al. [41] but different from the report by Zheng et al. [27]. However, they did not explain the reason in detail. ...
The original stereoelectroencephalography frame-based implantation technique has been proven to be safe and effective. But this procedure is complicated and time-consuming. With the development of modern robotic technology, robot-guided intracerebral electrodes implantation is being implemented at many epilepsy centers. We retrospectively analyzed the results of 147 patients who underwent SEEG electrode implantation surgery at our hospital. Robot-guided surgery was performed on 87 patients from January 2018 to December 2019. The remaining 60 patients received frame-based surgery from June 2015 to June 2016. 147 patients underwent a total of 149 SEEG electrode implantation procedures. The mean error of the entry point of the robot-guided surgery group was lower than that of the frame-based surgery group (1.48 ± 1.46 mm vs. 1.59 ± 0.9 mm, P < 0.001). Also, the robot group had a higher mean number of electrodes per patient (8.9 ± 2.2 vs. 7.9 ± 2.5, P = 0.004), a significantly shorter mean operative time (69.5 ± 23.3 min vs. 106.8 ± 39.8 min, P < 0.001), and mean time per electrode (7.9 ± 1.3 min vs. 13.5 ± 3.1 min, P < 0.001) than the frame-based group. In the robot-guided group, the target point (TP) error was positively correlated with skull thickness (P = 0.001) and negatively correlated with the electrode-skull angle (P = 0.041). The mean target point error and hemorrhage rates were also analyzed, but no differences were observed between the two groups. Robot-guided surgery has a higher entry point accuracy and efficiency. Electrode implantation accuracy was affected by the skull thickness and electrode-skull angle.
... Other studies have used intracortical microarrays to decode speech [36][37][38][39] or a neurotrophic electrode 40 to synthesize formant frequencies 41,42 from the motor cortex. An alternative measure of intracranial neural activity is stereotactic EEG (sEEG), in which electrode shafts are implanted into the brain through small burr holes 43 . sEEG is considered to be minimally invasive, as a large craniotomy is not necessary and the infection risk is therefore smaller 44 . ...
Speech production is an intricate process involving a large number of muscles and cognitive processes. The neural processes underlying speech production are not completely understood. As speech is a uniquely human ability, it can not be investigated in animal models. High-fidelity human data can only be obtained in clinical settings and is therefore not easily available to all researchers. Here, we provide a dataset of 10 participants reading out individual words while we measured intracranial EEG from a total of 1103 electrodes. The data, with its high temporal resolution and coverage of a large variety of cortical and sub-cortical brain regions, can help in understanding the speech production process better. Simultaneously, the data can be used to test speech decoding and synthesis approaches from neural data to develop speech Brain-Computer Interfaces and speech neuroprostheses.
... It has been shown to be safe and effective in adults and older children but has been sparsely used in children less than two years old due to concerns about pin fixation in thin bone, registration accuracy, and bolt security [2][3][4]. As such, most current series of pediatric invasive EEG explorations do not include young participants, and, when they do, SEEG is often not utilized for these patients [1,[4][5][6][7][8][9][10][11][12][13][14][15][16]. Recent national survey data further suggests SEEG is infrequently utilized in very young patients [17]. ...
... SEEG has generally been avoided in the very young. Among series of SEEG involving pediatric patients, the overall reported age range has been 20 months to 69 years [1,[4][5][6][7][8][10][11][12][13][14][15][16][18][19][20][21]. Five groups have included patients under three years old, and four groups under two years old, with the youngest patient reported being 20 months old, three months older than our patient [8,11,18,19]. ...
Stereoelectroencephalography (SEEG) is an increasingly popular invasive monitoring technique that allows three-dimensional definition of epileptogenic zones (EZ) throughout the cerebrum. It has been shown to be safe and effective in adults and older children but has been sparsely used in children less than two years old due to concerns about pin fixation in thin bone, registration accuracy, and bolt security. As such, most current series of pediatric invasive explorations do not include such young participants, and, if they do, SEEG is not utilized for these patients. Recent national survey data further suggest SEEG is infrequently utilized in very young patients. We present a novel case of application of SEEG to localize an EZ in a 17-month-old patient with thin bone, an open fontanelle, and severe medication-resistant epilepsy due to tuberous sclerosis complex (TSC), with excellent accuracy, surgical outcome, and seizure remission.
... The performance of a single immediate postimplantation CT scan is the most used [5,[7][8][9][10][11][12][13][14][15][16]. Few studies report late postoperative -after 24 h -or postexplantation additional imaging studies [1,[17][18][19][20][21][22][23][24]. ...
Background
Stereo-electroencephalography (SEEG) is a well-known invasive diagnostic method for drug-resistant epilepsy (DRE). Its rate of complications is relatively low, being the intracranial hemorrhage (ICH) the most relevant. Most centers perform immediate imaging studies after SEEG to rule out complications. However, delayed intracranial hemorrhages (DIH) can occur despite normal imaging studies in the immediate postoperative period.Methods
We performed a retrospective review of DRE pediatric patients operated on SEEG between April 2016 and December 2020 in our institution. After implantation, an immediate postoperative CT was performed to check electrode placement and rule out acute complications. An additional MRI was performed 24 h after surgery. We collected all postoperative hemorrhages and considered them as major or minor according to Wellmer´s classification.ResultsOverall, 25 DRE patients were operated on SEEG with 316 electrodes implanted. Three ICHs were diagnosed on postoperative imaging. Two of them were asymptomatic requiring no treatment, while the other needed surgical evacuation after clinical worsening. The total risk of hemorrhage per procedure was 12%, but just one third of them were clinically relevant. Two hemorrhages were not visible on immediate postoperative CT, being incidentally diagnosed in the 24 h MRI. We recorded them as DIH and are reported in detail.Conclusion
Few reports of DIH after SEEG exist in the literature. It remains unclear whether these cases are late occurring hemorrhages or immediate postoperative hemorrhages undiagnosed on initial imaging. According to our findings, we recommend to perform additional late postoperative imaging to diagnose these cases and manage them accurately.
... These electrodes require a large craniotomy. In the monitoring of epilepsy patients, in which almost all of the previous studies have been conducted, more and more centers utilize the less invasive stereotactic EEG (sEEG), which is measured with intracranial depth electrodes [21]. The use of sEEG for BCI has been discussed before [22] and one study demonstrates that imagined speech can be synthesized in real-time from sEEG recordings [23]. ...
Speech Neuroprostheses have the potential to enable communication for people with dysarthria or anarthria. Recent advances have demonstrated high-quality text decoding and speech synthesis from electrocorticographic grids placed on the cortical surface. Here, we investigate a less invasive measurement modality, namely stereotactic EEG (sEEG) that provides sparse sampling from multiple brain regions, including subcortical regions. To evaluate whether sEEG can also be used to synthesize high-quality audio from neural recordings, we employ a recurrent encoder-decoder framework based on modern deep learning methods. We demonstrate that high-quality speech can be reconstructed from these minimally invasive recordings, despite a limited amount of training data. Finally, we utilize variational feature dropout to successfully identify the most informative electrode contacts.
... This mini-mally invasive technique requires accurate implantation of depth electrodes using stereotactic methodology and has been increasingly used to identify epileptogenic foci (zones) as part of the epilepsy surgery workup in patients with medically refractory epilepsy. [3][4][5][6][7][8][9][10][11][12] ABBREVIATIONS CT = computed tomography; MRI = magnetic resonance imaging; SEEG = stereo-electroencephalography. ...
... 29 Higher in vivo accuracy of SEEG electrode positioning is obviously crucial, as it can lead to more successful epileptogenic zone identification, more precise resective surgery, and thus better seizure outcomes and fewer complications. 11 In robot-assisted SEEG patients, a median target point error of 1.7-2.7 mm has been reported, 6,9,14,30 compared to a 2.9-mm median target point deviation in non-robot-assisted cases. 11 An often ignored but important factor affecting accuracy is the maintenance of equipment. ...
... 11 In robot-assisted SEEG patients, a median target point error of 1.7-2.7 mm has been reported, 6,9,14,30 compared to a 2.9-mm median target point deviation in non-robot-assisted cases. 11 An often ignored but important factor affecting accuracy is the maintenance of equipment. The neuromate robot, for example, requires calibration every 3 months, and the Leksell stereotactic frame requires annual maintenance that includes an accuracy check. ...
OBJECTIVE
The safety of stereo-electroencephalography (SEEG) has been investigated; however, most studies have not differentiated pediatric and adult populations, which have different anatomy and physiology. The purpose of this study was to assess SEEG safety in the pediatric setting, focusing on surgical complications and the identification of patient and surgical risk factors, if any. The authors also aimed to determine whether robot assistance in SEEG was associated with a change in practice, surgical parameters, and clinical outcomes.
METHODS
The authors retrospectively studied all SEEG cases performed in their department from December 2014 to March 2020. They analyzed both demographic and surgical variables and noted the types of surgery-related complications and their management. They also studied the clinical outcomes of a subset of the patients in relation to robot-assisted and non–robot-assisted SEEG.
RESULTS
Sixty-three children had undergone 64 SEEG procedures. Girls were on average 3 years younger than the boys (mean age 11.1 vs 14.1 years, p < 0.01). The overall complication rate was 6.3%, and the complication rate for patients with left-sided electrodes was higher than that for patients with right-sided electrodes (11.1% vs 3.3%), although the difference between the two groups was not statistically significant. The duration of recording was positively correlated to the number of implanted electrodes (r = 0.296, p < 0.05). Robot assistance was associated with a higher number of implanted electrodes (mean 12.6 vs 7.6 electrodes, p < 0.0001). Robot-assisted implantations were more accurate, with a mean error of 1.51 mm at the target compared to 2.98 mm in nonrobot implantations (p < 0.001). Clinical outcomes were assessed in the first 32 patients treated (16 in the nonrobot group and 16 in the robot group), 23 of whom proceeded to further resective surgery. The children who had undergone robot-assisted SEEG had better eventual seizure control following subsequent epilepsy surgery. Of the children who had undergone resective epilepsy surgery, 42% (5/12) in the nonrobot group and 82% (9/11) in the robot group obtained an Engel class IA outcome at 1 year (χ ² = 3.885, p = 0.049). Based on Kaplan-Meier survival analysis, the robot group had a higher seizure-free rate than the nonrobot group at 30 months postoperation (7/11 vs 2/12, p = 0.063). Two complications, whose causes were attributed to the implantation and head-bandaging steps, required surgical intervention. All complications were either transient or reversible.
CONCLUSIONS
This is the largest single-center, exclusively pediatric SEEG series that includes robot assistance so far. SEEG complications are uncommon and usually transient or treatable. Robot assistance enabled implantation of more electrodes and improved epilepsy surgery outcomes, as compared to those in the non–robot-assisted cases.
