Depth versus subdural temporal electrodes revisited: Impact on surgical outcome after resective surgery for epilepsy

Objective

To study retrospectively the impact of electrode modality (subdural or depth electrodes) during presurgical assessment on surgical outcome after temporal lobectomy.

一种新型硬脑膜下条片状埋藏电极在癫痫外科中的应用

作者设计并制作了硬脑膜下条片状电极.用于癫痫致痫灶的术前、术中定位,对44例癫痫病人,用它作致痫灶定位,使手术有效率达90.9%。它比头皮脑电图灵敏度高5～10倍。避免了肌电干扰,提高了信号/噪音比率。本文详细讨论了电极制作原理,手术适应证、置放电极的手术方法.优缺点及其防治。     

Indices of resective surgery effectiveness for intractable nonlesional focal epilepsy

Among 70 patients with intractable focal epilepsy and no specific lesion, as determined by both MRI (magnetic resonance imaging) and histopathology, outcome after resective surgery was polarized: 26 (37%) became seizure free (SF), and 27 (39%) were not helped. Eighteen (42%) of 43 standard temporal resections rendered patients SF, somewhat more than eight (30%) of 27 other procedures. To seek reliable prognostic factors, the subsequent correlative data compared features of the 26 SF patients with those of the 27 not helped. Although ictal semiology guided the site of surgical resection, it and other aspects of seizure and neurologic history failed to predict surgical outcome. However, two aspects of preoperative scalp EEGs correlated with SF outcomes: (a) among 25 patients in whom >50% of clinical seizures arose from the later resected lobe and no other origins, 18 (72%) became SF compared with seven (28%) of 25 with other ictal profiles; (b) 13 (93%) of 14 temporal lobe patients whose interictal and ictal EEGs lacked features indicative of multifocal epileptogenesis became SF compared with five (33%) of 15 with such components. The considered need for subdural (SD) EEG reduced SF outcome from 18 (90%) of 20 patients without SD to eight (24%) of 33 with SD; this likely reflected an insufficient congruity of ictal semiology and interictal and ictal scalp EEG for localizing epileptogenesis. Within this SD group, >50% of clinical seizure origins from a later resected lobe increased SF outcome somewhat: from two (14%) of 14 without this attribute to six (40%) of 15 with it; 100% of such origins increased SF outcome from two (12%) of 16 to six (46%) of 13.     

Depression in intractable partial epilepsy varies by laterality of focus and surgery

PURPOSE: Depression sometimes occurs after surgical treatment for medically intractable partial epilepsy. The risk of pre- and postsurgical depression may vary by laterality of seizure focus. We reviewed the pre- and postsurgical psychological assessments and clinical courses of patients to identify those at highest risk for postsurgical mood disorders. METHODS: Depression status was assessed in a consecutive series of epilepsy patients before and 1 year after epilepsy surgery with the use of Scale 2 of the MMPI-2 and a clinical depression index (CDI) scoring the occurrence of depressive symptoms, psychiatric referral, or attempted/completed suicide. Outcome at 1 year was modeled by regression techniques as functions of preoperative mood measurements, side of epilepsy surgery, and preoperative verbal intelligence. RESULTS: The CDI and Scale 2 MMPI-2 correlated significantly (r = 0.341; p < or = 0.01). Left (n = 54 subjects) and right (n = 53) surgery groups did not differ by sex, seizure outcome, age, education, age at first seizure, duration of epilepsy, or intellect. Higher presurgical depressive morbidity (p = 0.0037) and right-sided surgery (p = 0.0003) predicted higher postoperative CDI. Higher preoperative Scale 2 scores, indicating worse depressive traits, predicted worse postoperative Scale 2 scores (p < 0.0001). Although side of surgery did not predict Scale 2 scores, Scale 2 scores of patients with preoperative right-sided foci tended to have worse postsurgical Scale 2 scores (p = 0.08). Findings for the temporal lobectomy subgroup (n = 90) were similar to those of the overall sample. CONCLUSIONS: Patients undergoing right hemispheric epilepsy surgery, especially those with high presurgical depression-related morbidity, may be particularly susceptible to clinical depression. Our findings support other studies that show an interhemispheric modulation of depressive traits and symptoms.     

伴有癫癇发作的脑内病灶的手术治疗

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难治性癫痫侵袭性评估中颅内皮层电极的应用与并发症分析

目的探讨在难治性癫痫术前评估中颅内皮层电极埋藏的方法与安全性。方法回顾性分析湘雅医院功能神经外科2014年4月～2017年6月开展的65例颅内皮层电极埋置患者的临床资料,总结颅内皮层电极埋置在癫痫术前评估中的经验。结果 65例患者均采用开颅埋置皮层片状电极,其中38例辅助埋置深部电极。患者术后平均监测时间为10. 8天(2～28天)。术后颅内血肿8例,其中硬膜外血肿4例,硬膜下血肿4例,有3例患者因硬膜外血肿行手术清除血肿,术后伤口脑脊液漏12例,术后颅内感染3例,均为并发脑脊液漏患者,脑水肿1例,电极脱出1例。无因并发症放弃监测病例,无埋置手术长期并发症及神经功能受损病例。结论颅内皮层电极埋置在癫痫外科中是一项重要的安全有效的侵袭性术前评估方法,术后出血及感染是主要的并发症,适当的术中、术后处理将有助于避免相关并发症。     

Predictors of seizure outcome after temporal lobectomy for intractable epilepsy

OBJECTIVES: To assess predictors of outcome of temporal lobectomy for intractable epilepsy. MATERIAL AND METHODS: In 63 adult patients operated with anterior temporal lobectomy during 198892, we used logistic regression analysis to assess predictors of being seizure-free (Engel's class I) 2 years after surgery. As potential predictors, we included the following variables: gender, age at operation, age at onset of seizures, epilepsy duration, etiology, generalized vs not generalized seizures, seizure frequency, intelligence quotient, ictal electroencephalography, magnetic resonance imaging (MRI), single-photon emission computed tomography (SPECT), side of resection, and extent of the resection. RESULTS: About 44% of the surgery patients were seizure-free (Engel's class I) 2 years after surgery. In multivariate analysis (n = 55), MRI pathology defined as atrophy in the temporal lobe, angioma, tumor or mesial temporal sclerosis (odds ratio, OR 7.4, 95%CI: 1.7-32.9) and extent of the hippocampal resection (increase of 1 cm) (OR 2.2, 95%CI: 1.1-4.6) predicted being seizure-free. CONCLUSION: Focal pathology in preoperative MRI and the extent of the hippocampal resection were the only significant predictors of being seizure-free after 2 years.     

无病灶性癫术前长程颅内电极埋置的适应证探讨

目的探讨无病灶性顽固性癫手术前应用长程颅内电极埋置术定位致灶的适应证及可能将其省略的条件。方法回顾性分析82例术前MRI与CT证实无明显结构性病灶癫病人的手术治疗经验。根据我研究所制定的术前埋置电极适应证标准,采用电极埋置39例(埋置组),省略电极埋置43例(非埋置组)。术后随访1年以上,总结两组术前各项评估结果的特点,并比较手术预后效果。结果埋置组术后EngelⅠ与Ⅱ级25例(64.1%),非埋置组术后EngelⅠ与Ⅱ级20例(46.5%);两组比较,差异无统计学意义(P>0.05)。结论对于无病灶性顽固性癫病人,长程颅内电极监测是保障手术效果的一项重要手段。然而当发作间期异常放电焦点局限在单一脑叶并与发作起始点部位相一致时,如果此部位与发作症状学定位不悖,且在满足其他一定条件的前提下,少数病人可考虑省略颅内电极埋置而直接行致灶切除手术。     

颅内电极置入与脑功能区定位技术在功能区难治性癫疒间手术的应用

目的探讨颅内电极埋藏与脑功能区定位技术在功能区起始的难治性癫疒间手术的评估价值。方法回顾性分析7例难治性癫疒间的临床资料,头皮视频脑电图长程监测均考虑致疒间灶可能累及功能区,故行颅内电极置入术,再行皮质电极视频脑电图长程监测,记录发作间期和发作期脑电图,以判断致疒间皮质,并采用皮质电刺激行脑功能区定位,在指导术中尽可能切除致疒间皮质的同时,最大限度保护脑功能。结果癫疒间发作起始区切除2例,癫疒间起始区部分切除加周围皮质热灼5例。随访6个月~1年,术后运动及语言功能均保护良好6例,对侧肢体出现短暂运动障碍后恢复1例。结论颅内电极埋藏与脑功能区定位技术是功能区难治性癫疒间手术必要评估手段,有助于术前明确脑功能区和皮质放电区域,以及两者之间的关系,指导设计手术方式,最大限度提高病人术后生活质量。     

Clinical utility of intraoperative electrocorticography for epilepsy surgery: A systematic review and meta-analysis

Despite the widespread use of intraoperative electrocorticography (iECoG) during resective epilepsy surgery, there are conflicting data on its overall efficacy and inability to predict benefit per pathology. Given the heterogeneity of iECoG use in resective epilepsy surgery, it is important to assess the utility of interictal-based iECoG. This individual patient data (IPD) meta-analysis seeks to identify the benefit of iECoG during resective epilepsy surgery in achieving seizure freedom for various pathologies. Embase, Scopus, and PubMed were searched from inception to January 31, 2021 using the following terms: "ecog", "electrocorticography", and "epilepsy". Articles were included if they reported seizure freedom at ≥12-month follow-up in cohorts with and without iECoG for epilepsy surgery. Non-English articles, noncomparative iECoG cohorts, and studies with <10% iECoG use were excluded. This meta-analysis followed the PRISMA 2020 guidelines. The primary outcome was seizure freedom at last follow-up and time to seizure recurrence, if applicable. Forest plots with random effects modeling assessed the relationship between iECoG use and seizure freedom. Cox regression of IPD was performed to identify predictors of longer duration of seizure freedom. Kaplan–Meier curves with log-rank test were created to visualize differences in time to seizure recurrence. Of 7504 articles identified, 18 were included for study-level analysis. iECoG was not associated with higher seizure freedom at the study level (relative risk = 1.09, 95% confidence interval [CI] = 0.96–1.23, p = .19, I² = 64%), but on IPD (n = 7 studies, 231 patients) iECoG use was independently associated with more favorable seizure outcomes (hazard ratio = 0.47, 95% CI = .23–.95, p = .037). In Kaplan–Meier analysis of specific pathologies, iECoG use was significantly associated with longer seizure freedom only for focal cortical dysplasia (FCD; p < .001) etiology. Number needed to treat for iECoG was 8.8, and for iECoG in FCD it was 4.7. We show iECoG seizure freedom is not achieved uniformly across centers. iECoG is particularly beneficial for FCD etiology in improving seizure freedom.     

皮层脑电图监测在颅脑病变伴发癫(癎)手术中的应用

目的 探讨皮层脑电图监测在颅脑病变伴发癫(癎)手术中的应用价值.方法 回顾分析58 例皮层脑电监测下手术切除病变及致(癎)灶患者临床资料.结果 所有患者在切除病变后复查皮层脑电图仍有(癎)样放电,其中37 例行扩大皮层切除,18 例加行皮层热灼术,3 例加行MST.术后1 /2 ～6 年随访发现癫(癎)控制达到EngelⅠ级32 例,EngelⅡ12 例,Engel Ⅲ级3 例,Engel Ⅳ 11 例,术后癫(癎)控制有效率为84.48%.结论 对于颅脑病变伴发癫(癎)的患者,应在皮层脑电图监测下进行手术,且在切除病变的同时一并将致(癎)灶切除.     

VNS in patients with previous unsuccessful resective epilepsy surgery: antiepileptic and psychotropic effects

OBJECTIVES: To assess the efficacy of vagus nerve stimulation (VNS) in patients with medically and surgically intractable complex partial seizures (CPS). PATIENTS AND METHODS: Sixteen patients with previous temporal [15] and frontal [one] resections were treated with VNS between 1994 and 1999 at King's College Hospital, London, UK. Post-operative video-electroencephalogram telemetry had shown that CPS started from the operated side in 12 patients, contralaterally in three and bilaterally independently in one. RESULTS: Three patients (18.75%) had 50% or more reduction in seizure frequency, but one showed severe worsening of epilepsy, which remitted upon VNS discontinuation. The antiepileptic effect of VNS was not different with respect to the type of operation (anterior temporal lobectomy vs amygdalohippocampectomy), the side of operation, or the side of seizure onset. We observed psychotropic effects in two patients with post-ictal psychosis, in two others with depression, and in a child with severe behavioral disorder. CONCLUSIONS: VNS may have a rather limited antiepileptic role to play in patients with persistent seizures following epilepsy surgery, but may independently possess useful antipsychotic and mood-stabilizing properties.     

Cortical resection with electrocorticography for intractable porencephaly-related partial epilepsy

PURPOSE: We evaluated the results of cortical resection of epileptogenic tissue for treatment of intractable porencephaly-related epilepsy. METHODS: We examined clinical features, electrophysiological data, surgical findings, and seizure outcomes after cortical resection in eight patients with intractable epilepsy related to porencephalic cysts. RESULTS: All eight patients had hemiparesis. Five retained motor function in the hemiparetic extremities; six retained visual fields. All had partial seizures, six with secondary generalization. Seven patients had simple and three had complex partial seizures (CPSs); two also had drop attacks. Four patients had multiple seizure types. Long-term scalp video-EEG (LVEEG) localized interictal epileptic abnormalities that anatomically corresponded to the cyst location in three patients. LVEEG recorded ictal-onset zones in five; these anatomically corresponded to the cyst location in three of the five. EEG recorded generalized seizures in two patients, hemispheric in one, and multifocal in two. Intraoperative electrocorticography (ECoG) revealed interictal epileptic areas extending beyond the margins of the cyst in seven patients. We resected ECoG-localized interictal epileptic areas completely in five patients and partially in two. Cortical resection was based on seizure semiology and LVEEG in one patient whose ECoG showed no epileptiform discharges. After a minimum follow-up of 1 year, six patients had excellent seizure outcome (Engel class I), and two had a >90% seizure reduction (Engel class III) without complications. CONCLUSIONS: Cortical resection guided by ECoG allows preservation of motor function and visual field and provides an effective surgical procedure for treatment of intractable epilepsy secondary to porencephaly.     

Predictive factors of postoperative outcome in the elderly after resective epilepsy surgery

ObjectiveTo evaluate the efficiency of resective epilepsy surgery (RES) in patients over 50 years and determine prognostic factors.ResultsOver the 147 patients over 50 years (54.9 ± 3.8 years [50–69]) coming from 8 specialized French centres for epilepsy surgery, 72.1%, patients were seizure-free and 91.2% had a good outcome 12 months after RES. Seizure freedom was not associated with the age at surgery or duration of epilepsy. In multivariate analysis, seizure freedom was associated with MRI and neuropathological hippocampal sclerosis (HS) (P = 0.009 and P = 0.028 respectively), PET hypometabolism (P = 0.013), temporal epilepsy (P = 0.01). On the contrary, the need for intracranial exploration was associated with a poorer prognosis (P = 0.001). Postoperative number of antiepileptic drugs was significantly lower in the seizure-free group (P = 0.001). Neurological adverse event rate after surgery was 21.1% and 11.7% of patients had neuropsychological adverse effects overall transient.ConclusionsRES is effective procedure in the elderly. Even safe it remains at higher risk of complication and population should be carefully selected. Nevertheless, age should not be considered as a limiting factor, especially when good prognostic factors are identified.     

Natural history of recurrent seizures after resective surgery for epilepsy.

Seizures persist or recur in 20-60% of patients after resective surgery for intractable partial epilepsy. Further information about the natural course of these seizures is lacking in the literature. During one decade of epilepsy surgery at a single institution, we identified 72 patients with recurrent postoperative seizures after resective procedures for epilepsy. Prospectively compiled seizure diaries, hospital records, and outpatient office records were reviewed and supplemented by telephone communications to assess subsequent seizure frequency. Follow-up data was available ranging from 6 months to 7 years 5 months (mean 3 years 5 months). The likelihood of persistent seizures and recurrent intractability was examined with life-tables. Seizures recurred within the first postoperative year in 86% of patients and were similar to preoperative events in 74% of patients. After the first seizure recurrence, there was 80% likelihood of persistent seizures in the next 6 years and 40% likelihood of intractability (more than one seizure a month despite optimal medical therapy). The interval until recurrence within the first postoperative year did not affect the likelihood of subsequent seizures or intractability. Late seizure recurrence (after the first year) was not associated with any instances of subsequent intractability. Recurrent seizures after extratemporal resections were more likely to become persistent and intractable than seizures recurring after temporal resections. This information provides rational prognostication and assists in counseling patients with recurrent seizures after resective surgery for intractable epilepsy.     

Multiple subpial transection for intractable partial epilepsy: an international meta-analysis

PURPOSE: Because the number and variety of patients at any single facility is not sufficient for clinical or statistical analysis, data from six major epilepsy centers that performed multiple subpial transections (MSTs) for medically intractable epilepsy were collected. METHODS: A meta-analysis was performed to elucidate the indications and outcome, and to assess the results of the procedure. Overall, 211 patients were represented with data regarding preoperative evaluation, procedures, seizure types and frequencies before and after surgery, postoperative deficits, and demographic information. Fifty-three patients underwent MST without resection. RESULTS: In patients with MST plus resection, excellent outcome (>95% reduction in seizure frequency) was obtained in 87% of patients for generalized seizures, 68% for complex partial seizures, and 68% for simple partial seizures. For the patients who underwent MST without resection, the rate of excellent outcome was only slightly lower, at 71% for generalized, 62% for complex partial, and 63% for simple partial seizures. EEG localization, age at epilepsy onset, duration of epilepsy, and location of MST were not significant predictors of outcome for any kinds of seizures after MST, with or without resection. New neurologic deficits were found in 47 patients overall, comparable in MST with resection (23%) or without (19%). CONCLUSIONS: These preliminary results suggest that MST has efficacy by itself, with minimal neurologic compromise, in cases in which resective surgery cannot be used to treat uncontrolled epilepsy. MST should be investigated as a stand-alone procedure to allow further development of criteria and predictive factors for outcome.     

Outcome of surgical treatment in non-lesional intractable childhood epilepsy

PurposeThe aim of this study is to investigate seizure outcomes following epilepsy surgery in non-lesional neocortical pediatric epilepsy.MethodsWe performed a retrospective study on 27 patients with intractable childhood epilepsy who received epilepsy surgery between 1999 and 2006 at Sang-gye Paik Hospital and Severance Children's Hospital. None of the patients had any detectable lesions on MRI. Surgical outcome was assessed at least 2 years postoperatively; clinical characteristics, surgical outcome, pathologic findings, types of surgery, localizing features on SPECT, FDG-PET, and long-term video-EEG were reviewed.ResultsEighteen patients (67%) demonstrated an Engel class I outcome postoperatively. The mean follow-up duration was 4.3 years (range, 2.2–9 years). Eighteen out of 27 cases (67%) showed focal localizing features on ictal SPECT, and 21 of 27 cases (78%) showed abnormal findings on PET. Single lobectomy was the most common procedure, and was performed in 20 patients (74%). Multilobar resection was performed in seven patients (26%). Cortical dysplasia was the most common finding during pathological examination, and was observed in 15 (56%) cases. In addition, gliosis was found in two patients (7%) and non-specific pathological findings were described in 10 patients (37%).ConclusionsIn children with intractable epilepsy and a MRI demonstrating no abnormal lesions, epileptic surgery should be strongly considered when cortical pathology can be identified from other studies.     

Long-term seizure outcome of surgery versus no surgery for drug-resistant partial epilepsy: A review of controlled studies

A majority of patients with formerly drug-resistant temporal lobe epilepsy become seizure-free after surgery. However, apart from one 12-month randomized trial, it is unclear how many become seizure-free because of surgery. To determine the net benefit of surgery, we performed a systematic review and meta-analysis of the published evidence of how many patients in similar studies become seizure-free without surgery. Of 155 potentially eligible articles reviewed in full text, 29 (19%) fulfilled eligibility criteria. After excluding 9 publications, 20 studies form the base of evidence. Overall, 719 of 1,621 (44%) of patients with mostly temporal lobe surgery were seizure-free compared to 139 of 1113 (12%) of nonoperated controls [pooled random effects relative risk (RR) 4.26, 95% confidence interval (CI) 3.03–5.98]. The pooled risk difference in favor of surgery was 42% (95% CI 32–51%). We found no comparative outcome data in patients with extratemporal lobe epilepsy only. The available evidence from mostly nonrandomized observational studies indicates that in appropriately selected patients with drug-resistant temporal lobe epilepsy, the combination of surgery with medical treatment is 4 times as likely as medical treatment alone to achieve freedom from seizures.