Stereoelectroencephalography-guided Radiofrequency Thermocoagulation Research Articles

Disrupting the epileptogenic network with stereoelectroencephalography-guided radiofrequency thermocoagulation.

Stereoelectroencephalography-guided radiofrequency thermocoagulation (SEEG-guided RF-TC) is a treatment option for focal drug-resistant epilepsy. In previous studies, this technique has shown seizure reduction by ≥50% in 50% of patients at 1 year. However, the relationship between the location of the ablation within the epileptogenic network and clinical outcomes remains poorly understood. Seizure outcomes were analyzed for patients who underwent SEEG-guided RF-TC and across subgroups depending on the location of the ablation within the epileptogenic network, defined as SEEG sites involved in seizure generation and spread. Eighteen patients who had SEEG-guided RF-TC were included. SEEG-guided seizure-onset zone ablation (SEEG-guided SOZA) was performed in 12 patients, and SEEG-guided partial seizure-onset zone ablation (SEEG-guided P-SOZA) in 6 patients. The early spread was ablated in three SEEG-guided SOZA patients. Five patients had ablation of a lesion. The seizure freedom rate in the cohort ranged between 22% and 50%, and the responder rate between 67% and 85%. SEEG-guided SOZA demonstrated superior results for both outcomes compared to SEEG-guided P-SOZA at 6 months (seizure freedom p = .294, responder rate p = .014). Adding the early spread ablation to SEEG-guided SOZA did not increase seizure freedom rates but exhibited comparable effectiveness regarding responder rates, indicating a potential network disruption.

Stereoelectroencephalography-guided radiofrequency thermocoagulation of the epileptogenic zone: a potential treatment and prognostic indicator for subsequent excision surgery.

To evaluate the safety and efficacy of stereoelectroencephalography (SEEG)-guided radiofrequency thermocoagulation (RFTC) for drug-resistant focal epilepsy and investigate the relationship between post-RFTC remission duration and delayed excision surgery effectiveness. We conducted a retrospective analysis of 43 patients with drug-resistant focal epilepsy who underwent RFTC via SEEGelectrodes. After excluding three, the remaining 40 were classified into subgroups based on procedures and outcomes. Twenty-four patients (60%) underwent a secondary excision surgery. We determined the predictive value of RFTC outcome upon subsequent surgical outcome by categorizing the delayed secondary surgery outcome as success (Engel I/II) versus failure (Engel III/IV). Demographic information, epilepsy characteristics, and the duration of seizure freedom after RFTC were assessed. Among 40 patients, 20% achieved Engel class I with RFTC alone, while 24 underwent delayed secondary excision surgery. Overall, 41.7% attained Engel class I, with a 66.7% success rate combining RFTC with delayed surgery. Seizure freedom duration was significantly longer in the success group (mean 4.9months, SD = 2.7) versus the failure group (mean 1.9months, SD = 1.1; P = 0.007). A higher proportion of RFTC-only and delayed surgical success group patients had preoperative lesional findings (p = 0.01), correlating with a longer time to seizure recurrence (p < 0.05). Transient postoperative complications occurred in 10%, resolving within a year. This study demonstrates that SEEG-guided RFTC is a safe and potential treatment option for patients with drug-resistant focal epilepsy. A prolonged duration of seizure freedom following RFTC may serve as a predictive marker for the success of subsequent excision surgery.

Frameless robot-assisted stereoelectroencephalography-guided radiofrequency: methodology, results, complications and stereotactic application accuracy in pediatric hypothalamic hamartomas

ObjectiveWe 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.MethodsChildren 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.ResultsA 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 &amp;lt; 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).ConclusionRobot-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.

Utility of hybrid PET/MRI in stereoelectroencephalography guided radiofrequency thermocoagulation in MRI negative epilepsy patients.

Hybrid positron emission tomography/magnetic resonance imaging (PET/MRI) is a novel advanced non-invasive presurgical examination tool for patients with drug-resistant epilepsy (DRE). This study aims to evaluate the utility of PET/MRI in patients with DRE who undergo stereoelectroencephalography-guided radiofrequency thermocoagulation (SEEG-guided RFTC). This retrospective study included 27 patients with DRE who underwent hybrid PET/MRI and SEEG-guided RFTC. Surgery outcome was assessed using a modified Engel classification, 2 years after RFTC. Potential areas of the seizure onset zone (SOZ) were identified on PET/MRI and confirmed by SEEG. Fifteen patients (55%) became seizure-free after SEEG-guided RFTC. Engel class II, III, and IV were achieved in six, two, and four patients, respectively at the 2 years follow-up. MRI was negative in 23 patients and structural abnormalities were found in four patients. Hybrid PET/MRI contributed to the identification of new structural or metabolic lesions in 22 patients. Concordant results between PET/MRI and SEEG were found in 19 patients in the identification of SOZ. Among the patients with multifocal onset, seizure-free status was achieved in 50% (6/12). SEEG-guided RFTC is an effective and safe treatment for drug-resistant epilepsy. Hybrid PET/MRI serves as a useful tool for detecting the potential SOZs in MRI-negative patients and guide the implantation of SEEG electrodes. Patients with multifocal epilepsy may also benefit from this palliative treatment.

Changes in local and network brain activity after stereotactic thermocoagulation in patients with drug-resistant epilepsy.

Stereoelectroencephalography-guided radiofrequency thermocoagulation (SEEG-guided RF-TC) aims to reduce seizure frequency by modifying epileptogenic networks through local thermocoagulative lesions. Although RF-TC is hypothesized to functionally modify brain networks, reports of changes in functional connectivity (FC) following the procedure are missing. We evaluated, by means of SEEG recordings, whether variation in brain activity after RF-TC is related to clinical outcome. Interictal SEEG recordings from 33 patients with drug-resistant epilepsy (DRE) were analyzed. Therapeutic response was defined as a >50% reduction in seizure frequency for at least 1 month following RF-TC. Local (power spectral density [PSD]) and FC changes were evaluated in 3-min segments recorded shortly before (baseline), shortly after, and 15 min after RF-TC. The PSD and FC strength values after thermocoagulation were compared with baseline as well as between the responder and nonresponder groups. In responders, we found a significant reduction in PSD after RF-TC in channels that were thermocoagulated for all frequency bands (p = .007 for broad, delta and theta, p <.001 for alpha and beta bands). However, we did not observe such PSD decrease in nonresponders. At the network level, nonresponders displayed a significant FC increase in all frequency bands except theta (broad, delta, beta band: p <.001; alpha band: p <.01), although responders showed a significant FC decrease in delta (p <.001) and alpha bands (p <.05). Nonresponders showed stronger FC changes with respect to responders exclusively in TC channels (broad, alpha, theta, beta: p >.05; delta: p = .001). Thermocoagulation induces both local and network-related (FC) changes in electrical brain activity of patients with DRE lasting for at least 15 min. This study demonstrates that the observed short-term modifications in brain network and local activity significantly differ between responders and nonresponders and opens new perspectives for studying the longer-lasting FC changes after RF-TC.

Stereoelectroencephalography-Guided Radiofrequency Thermocoagulation of Epileptic Foci in the Eloquent Motor Cortex: Feasibility, Safety, and Efficacy

To assess safety and long-term outcome of stereoelectroencephalography (SEEG)-guided radiofrequency thermocoagulation (RFTC) of epileptic foci in eloquent motor areas. We retrospectively reviewed medical charts and surgical features of 15 patients with drug-resistant focal epilepsy in eloquent motor areas treated between 2017 and 2021. All patients underwent SEEG-guided RFTC as the first option. General characteristics, SEEG findings, morbidity, and seizure outcome after RFTC were analyzed to extract the potential value of SEEG-guided RFTC for epileptic foci in eloquent motor areas. There were 12 male and 3 female patients. Mean age at RFTC was 25 ± 8.5 years (range, 14-48 years), and mean duration of epilepsy before SEEG was 9.5 ± 7.0 years (range, 2-26 years). Mean follow-up period was 22.1 months (range, 8-41 months). Magnetic resonance imaging findings were negative in 2 cases, suspected focal cortical dysplasia in 10 cases, central region band heterotopias in 2 cases, and malformations of cortical development in 1 case. RFTC sites included primary precentral area (M1) (7, 46.7%), paracentral lobule (4, 26.7%), supplemental motor area (2, 13.3%), and premotor area (2, 13.3%). Of 15 patients, 12 (80%) experienced a ≥75% decrease in seizure frequency, of whom 9 (60%) experienced a long-term seizure-free period (10-29 months, mean 21.3 months). Three (20%) patients did not benefit from RFTC. Nine patients had neurological deficits immediately after RFTC (transient in 8 patients [3 days to 3 weeks] and prolonged in 1 patient). SEEG-guided RFTC for epileptic foci in eloquent motor areas seems to be a safe and effective procedure. It could be the first option for drug-resistant epilepsy that is not amenable to surgical resection, especially for extremally focused epileptic foci in the cortex close to or inside the central region. Larger series and prospective studies are necessary to validate our conclusions.

Stereoelectroencephalography-guided radiofrequency thermocoagulation for hypothalamic hamartoma: Electroclinical patterns and the relationship with surgical prognosis

BackgroundRadiofrequency thermocoagulation (RFTC) guided by stereo-electroencephalography (SEEG) has been proved to be a safe method to reduce seizure frequency in patients with drug-resistant epilepsy. However, there are few reports addressing the value and safety of this procedure in hypothalamic hamartoma (HH). ObjectiveTo present the results of our experience using SEEG-guided RFTC in HH patients with drug-resistant epilepsy, and identify outcome predictors. MethodsWe retrospectively reviewed the clinical and surgical characteristics of 27 HH-related patients with epilepsy in our center between 2015 and 2019. All patients underwent invasive recordings with SEEG before RFTC was performed. We reported surgical outcome predictors and postoperative follow-up concerning safety and efficacy (mean follow-up, 27.3 months; range, 12–63). Surgical strategy was also analyzed. ResultsNineteen patients (70.4%) achieved Engel’s class I outcome, while 4 patients (14.8%) did not show significant improvement. Of all observed seizures, two different onset patterns of intracranial electrophysiology recorded by SEEG were observed. Patients presented with focal low-voltage fast activity were more likely to obtain seizure freedom (p = 0.045), while classification (p = 0.478), volume (p = 0.546), history of resection (p = 0.713), seizure types (p = 0.859), or seizure duration (p = 0.415) showed no significant effect on the outcome. Weight gain was the most common long-term complication (18.5%). ConclusionThe SEEG can guide the ablation of HH and serve as an important factor to predict favorable seizure outcomes. Radiofrequency thermocoagulation guided by SEEG can offer a minimally invasive and low-risk surgical approach with excellent outcomes. Disconnecting the attachment of HH should be the appropriate strategy to obtain the best seizure outcome.

Optimized stereoelectroencephalography-guided radiofrequency thermocoagulation in the treatment of patients with focal epilepsy.

Epilepsy is a severe health disorder affecting people of all ages with high prevalence worldwide. The introduction of new antiepileptic drugs has yielded notable effects in recent decades, yet there are still approximately 30% of patients with seizures refractory to medical therapy. Open surgical resection is widely accepted as a highly effective approach for the treatment of drug-resistant focal epilepsy if the epileptogenic zone can be precisely delineated. However, concerns about the impact of open surgery on brain function have driven considerable interest in less invasive techniques. Clinically, stereoelectroencephalography (SEEG) offers a unique means of exploring the pathophysiologic process and accurately mapping the epileptogenic network in presurgical evaluations for patients with epilepsy because of insufficient information from other noninvasive investigations. Moreover, SEEG-guided radiofrequency thermocoagulation (SEEG-guided RF-TC), which ablates lesions directly through the recording electrodes according to electroclinical evidence, has emerged as a promising, minimally invasive modality with notable preservation of neurocognitive functions. This critical review summarizes the technical details of the parameters and the selection of patients for SEEG-guided RF-TC based on the literature as well as our experiences. With respect to the parameters, the power and duration of RF-TC are discussed. In particular, an optimized SEEG-guided RF-TC modality that integrates more contacts from multiple different electrodes to create a confluent lesioning field is proposed for a more curative effect in comparison to the current protocol of palliative treatment in which RF-TC selectively disrupts critical hubs in the epileptic network through contiguous contacts within the range of a single electrode. Currently, SEEG-guided RF-TC is indicated for a variety of small, deeply seeded and well-demarcated epileptogenic foci, such as deep heterotopic nodules and hypothalamic hamartoma. The efficacy of treating patients with focal cortical dysplasias in the eloquent cortex and with mesial temporal lobe epilepsy associated with hippocampal sclerosis needs to be further determined. Given the small number of patients reported, randomized controlled trials are necessary to compare the efficacy of SEEG-guided RF-TC with conventional methods in the future.

Stereoelectroencephalography-guided radiofrequency thermocoagulation for the treatment of hypothalamic hamartoma related epilepsy

Objective To discuss the clinical application value of stereo-electroencephalography (SEEG) guided radiofrequency thermocoagulation (RF-TC) in the treatment of hypothalamic hamartoma (HH) related epilepsy. Methods A retrospective analysis was conducted on the clinical data of 7 consecutive patients with epilepsy caused by HH who underwent SEEG guided RF-TC at Department of Neurosurgery, Beijing Fengtai Hospital from June 2015 to January 2018. The clinical data included detailed history of illness, semiology, electroencephalography (EEG) and imaging results. Presurgical evaluation suggested that the epileptogenic zone was hypothalamic hamartoma. Then the SEEG electrodes were implanted using stereotactic frame and video EEG monitoring was conducted. Contacts with seizure onset patterns were chosen for ablation through RF-TC. After the ablation, video-EEG monitoring was still carried out. If the epileptic discharge did not disappear, the second RF-TC was carried out until the epileptic discharge disappeared. The postoperative complications were analyzed and post-operative seizure outcome was evaluated based on the Engel outcome classification at follow-up with telephone or clinical visits. Results Seven patients were followed up with a duration of 19.6±11.1 months. Among them, 5 were seizure free (EngelⅠ) and 1 achieved 75% decrease (Engel Ⅲ) in seizure frequency. One case had no obvious improvement (Engel Ⅳ). Postoperative complications occurred in 3 patients which included hyperthermia, lethargy, diabetes insipidus, electrolyte disorder and memory decline. All complications were resolved after treatment. Conclusion This study has suggested that SEEG guided RF-TC is an effective and safe treatment for seizure control in patients with HH. Complete disconnection between hypothalamus and hamartoma with RF-TC is essential for favorable surgical outcome. Key words: Epilepsy; Stereoelectroencephalography; Hypothalamic hamartoma; Radiofrequency thermocoagulation

Radiofrequency Energy and Electrode Proximity Influences Stereoelectroencephalography-Guided Radiofrequency Thermocoagulation Lesion Size: An In Vitro Study with Clinical Correlation.

Radiofrequency thermocoagulation of epileptogenic foci via stereoelectroencephalography (SEEG) electrodes has been suggested as a treatment for medically intractable epilepsy, but reported outcomes have been suboptimal, possibly because lesions generated using conventional high-energy radiofrequency parameters are relatively small. To describe a technique of delivering low energy across separate SEEG electrodes in order to create large confluent radiofrequency lesions. The size and configuration of radiofrequency lesions using different radiofrequency intensity and interelectrode distance was assessed in egg whites. Magnetic resonance images (MRI) from 3 patients who had undergone radiofrequency lesion creation were evaluated to determine the contribution of lesion intensity and electrode separation on lesion size. Electroencephalography, MRI, and clinical data were assessed before and after lesion creation. Both in Vitro and in Vivo analysis revealed that less energy paradoxically produced larger lesions, with the largest possible lesions produced when radiofrequency power was applied for long duration at less than 3 W. Linear separation of electrodes also contributed to lesion size, with largest lesions produced when electrodes were separated by a linear distance of between 5 and 12 mm. Clinical lesions produced using these parameters were large and resulted in improvement in interictal and ictal activity. Radiofrequency lesions produced using low-energy delivery between SEEG electrodes in close proximity can produce a large lesion. These findings might have advantages for treatment of focal epilepsy.

Stereo electroencephalography-guided radiofrequency thermocoagulation in drug-resistant focal epilepsy: A new pediatric technique to guide the surgery

Stereo electroencephalography-guided radiofrequency thermocoagulation in drug-resistant focal epilepsy: A new pediatric technique to guide the surgery

Stereoelectroencephalography-Guided Radiofrequency Thermocoagulation (SEEG-Guided RF-TC) in Patients with Drug-Resistant Focal Epilepsy

For some patients with drug-resistant focal epilepsy, we usually select conventional surgical resection, which has brought better outcomes. However, others are not eligible for a conventional open surgical resection of the epileptogenic zone because of the proximity of a functional area or the implication of a larger epileptogenic network. Initially, stereoelectroencephalography (SEEG) exploration was a method of electroencephalography recording that was used in the presurgical evaluation of epileptic patients with complex epilepsy. Later, intracerebral electrodes used for SEEG were applied to produce radio frequency thermocoagulation (RF-TC) in epileptic patients. SEEG-guided RF-TC has produced some promising results, especially in the last dacade. Now, it has become popular as a palliative treatment to reduce seizure frequency in patients with drug-resistant focal epilepsy. This article presents a review of SEEG-guided RF-TC.

Stereoelectroencephalography-guided radiofrequency thermocoagulation (SEEG-guided RF-TC) in patients with drug-resistant focal epilepsy

Stereoelectroencephalography-guided radiofrequency thermocoagulation (SEEG-guided RF-TC) in patients with drug-resistant focal epilepsy

Stereo electroencephalography-guided radiofrequency thermocoagulation (SEEG-guided RF-TC) in drug-resistant focal epilepsy: Results from a 10-year experience.

Stereo electroencephalography (SEEG)-guided radiofrequency thermocoagulation (SEEG-guided RF-TC) has been proposed since 2004 as a possible treatment of some focal drug-resistant epilepsy. The aim of this study is to provide extensive data about efficacy and safety of SEEG-guided RF-TC. Over a 10-year period, 162 patients with drug-resistant focal epilepsy were eligible for SEEG-guided RF-TG during phase II invasive investigation by SEEG. All follow-up and safety data were collected prospectively. The primary outcome was seizure freedom at 2 months and at 1 year after SEEG-guided RF-TC. Secondary outcomes were the responders' rate (patient with at least 50% decrease in seizure frequency) and their long-term follow-up. Twenty-five percent of patients were seizure-free at 2 months and 7% at 1 year. We reported 67% of responders at 2 months and 48% at 1 year; 58% of responders maintained their status during the long-term follow-up. The seizure outcome was significantly better when the SEEG-guided RF-TC involved the occipital region (p = 0.007). When surgery followed an SEEG-guided RF-TC, the positive predictive value of being a responder 2 months after an SEEG-guided RF-TC and to be Engel's class I or II after surgery was 93%. We reported 1.1% of permanent deficit and 2.4% of transient side effects. Our results, gathered in a large population over a 10-year period, confirm that SEEG-guided RF-TC is a safe technique, being efficient in many cases. More than two thirds of patients showed a short-term improvement, and almost half of them were responders at 1-year follow-up. The technique appears to be especially interesting for limited epileptic zone inaccessible to surgery and when epilepsy is related to a large unilateral network (network disruption by multiple RF-TC). Furthermore, SEEG-guided RF-TC effect is a predictor of outcome after conventional cortectomy in patients eligible for surgery.

Stereoelectroencephalography-guided radiofrequency thermocoagulation in the epileptogenic zone: a retrospective study on 89 cases.

Radiofrequency thermocoagulation (RF-TC) of presumed epileptogenic lesions and/or structures has gained new popularity as a treatment option for drug-resistant focal epilepsy, mainly in patients with mesial temporal lobe epilepsy. The role of this minimally invasive procedure in more complex cases of drug-resistant epilepsy, which may require intracranial electroencephalographic evaluation, has not been fully assessed. This retrospective study reports on a case series of patients with particularly complex focal epilepsy who underwent stereoelectroencephalography (SEEG) evaluation with stereotactically implanted multicontact intracerebral electrodes for the detailed identification of the epileptogenic zone (EZ) and who received RF-TC in their supposed EZ (according to SEEG findings). Eighty-nine patients (49 male and 40 female; age range 2-49 years) who underwent SEEG evaluation and subsequent RF-TC of the presumed EZ at the authors' institution between January 2008 and December 2013 were selected. Brain MRI revealed structural abnormalities in 43 cases and no lesions in 46 cases. After SEEG, 67 patients were judged suitable for resective surgery (Group 1), whereas surgery was excluded for 22 patients (Group 2). Thermocoagulation was performed in each of these patients by using the previously implanted multicontact recording electrodes and delivering RF-generated currents to adjacent electrode contacts. The mean number of TC sites per patient was 10.6 ± 7.2 (range 1-33). Sustained seizure freedom occurred after TC in 16 patients (18.0%) (13 in Group 1 and 3 in Group 2). A sustained worthwhile improvement was reported by 9 additional patients (10.1%) (3 in Group 1 and 6 in Group 2). As a whole, 25 patients (28.1%) exhibited a persistent significant improvement in their seizures. More favorable results were observed in patients with nodular heterotopy (p = 0.0001389), those with a lesion found on MRI (not significant), and those with hippocampal sclerosis (not significant). Other variables significantly correlated to seizure freedom were the patient's age (p = 0.02885) and number of intralesional TC sites (p = 0.0271). The patients in Group 1 who did not benefit at all (21 patients) or who experienced only a transient benefit (30 patients) from TC underwent microsurgical resection of their EZ. Thermocoagulation was followed by severe permanent neurological deficits in 2 patients (an unexpected complex neuropsychological syndrome in one patient and an expected and anticipated permanent motor deficit in the other). This study provides evidence that SEEG-guided TC in the EZ may be a treatment option for particularly complex drug-resistant focal epilepsy that requires invasive evaluation. A small subset of patients who achieve seizure freedom or worthwhile improvement may avoid open surgery or take advantage of an otherwise unexpected treatment if resection is not an option. Patients with epileptogenic nodular heterotopy are probably ideal candidates for this treatment.