Surgical strategy for focal cortical dysplasia based on the analysis of the spike onset and peak zones on magnetoencephalography

2020 ◽  
Vol 133 (6) ◽  
pp. 1850-1862 ◽  
Author(s):  
Hiroshi Shirozu ◽  
Akira Hashizume ◽  
Hiroshi Masuda ◽  
Akiyoshi Kakita ◽  
Hiroshi Otsubo ◽  
...  
Keyword(s):  
Focal Cortical Dysplasia ◽  
Cortical Dysplasia ◽  
Complete Resection ◽  
Surgical Strategy ◽  
Class I ◽  
Type I ◽  
Incomplete Resection ◽  
Epileptogenic Zone ◽  
Current Dipole ◽  
Significant Difference

OBJECTIVEThe aim of this study was to elucidate the surgical strategy for focal cortical dysplasia (FCD) based on the interictal analysis on magnetoencephalography (MEG). For this purpose, the correlation between the spike onset zone (Sp-OZ) and the spike peak zone (Sp-PZ) on MEG was evaluated to clarify the differences in the Sp-OZ and its correlation with Sp-PZ in FCD subtypes to develop an appropriate surgical strategy.METHODSForty-one FCD patients (n = 17 type I, n = 13 type IIa, and n = 11 type IIb) were included. The Sp-OZ was identified by the summation of gradient magnetic-field topography (GMFT) magnitudes at interictal MEG spike onset, and Sp-PZ was defined as the distribution of the equivalent current dipole (ECD) at spike peak. Correlations between Sp-OZ and Sp-PZ distributions were evaluated and compared with clinical factors and seizure outcomes retrospectively.RESULTSGood seizure outcomes (Engel class I) were obtained significantly more often in patients with FCD type IIb (10/11, 90.9%) than those with type IIa (4/13, 30.8%; p = 0.003) and type I (6/17, 35.3%; p = 0.004). The Sp-OZ was significantly smaller (1 or 2 gyri) in type IIb (10, 90.9%) than in type IIa (4, 30.8%; p = 0.003) or type I (9, 53.0%; p = 0.036). Concordant correlations between the Sp-OZ and Sp-PZ were significantly more frequent in type IIb (7, 63.6%) than in type IIa (1, 7.7%; p = 0.015) or type I (1, 5.8%; p = 0.004). Complete resection of the Sp-OZ achieved significantly better seizure outcomes (Engel class I: 9/10, 90%) than incomplete resection (11/31, 35.5%) (p = 0.003). In contrast, complete resection of the Sp-PZ showed no significant difference in good seizure outcomes (9/13, 69.2%) compared with incomplete resection (11/28, 39.3%).CONCLUSIONSThe Sp-OZ detected by MEG using GMFT and its correlation with Sp-PZ were related to FCD subtypes. A discordant distribution between Sp-OZ and Sp-PZ in type I and IIa FCD indicated an extensive epileptogenic zone and a complex epileptic network. Type IIb showed a restricted epileptogenic zone with the smaller Sp-OZ and concordance between Sp-OZ and Sp-PZ. Complete resection of the Sp-OZ provided significantly better seizure outcomes than incomplete resection. Complete resection of the Sp-PZ was not related to seizure outcomes. There was a definite difference in the epileptogenic zone among FCD subtypes; hence, an individual surgical strategy taking into account the correlation between the Sp-OZ and Sp-PZ should be considered.

scholarly journals Resective surgery for medically refractory epilepsy using intraoperative MRI and functional neuronavigation: the Erlangen experience of 415 patients

2016 ◽  
Vol 40 (3) ◽  
pp. E15 ◽  
Author(s):  
Karl Roessler ◽  
Andrea Hofmann ◽  
Bjoern Sommer ◽  
Peter Grummich ◽  
Roland Coras ◽  
...  
Keyword(s):  
Surgical Procedures ◽  
Focal Cortical Dysplasia ◽  
Hippocampal Sclerosis ◽  
Cortical Dysplasia ◽  
Intraoperative Mri ◽  
Class I ◽  
Seizure Outcome ◽  
Incomplete Resection ◽  
Diffuse Glioma ◽  
Resection Volume

OBJECTIVE Intraoperative overestimation of resection volume in epilepsy surgery is a well-known problem that can lead to an unfavorable seizure outcome. Intraoperative MRI (iMRI) combined with neuronavigation may help surgeons avoid this pitfall and facilitate visualization and targeting of sometimes ill-defined heterogeneous lesions or epileptogenic zones and may increase the number of complete resections and improve seizure outcome. METHODS To investigate this hypothesis, the authors conducted a retrospective clinical study of consecutive surgical procedures performed during a 10-year period for epilepsy in which they used neuronavigation combined with iMRI and functional imaging (functional MRI for speech and motor areas; diffusion tensor imaging for pyramidal, speech, and visual tracts; and magnetoencephalography and electrocorticography for spike detection). Altogether, there were 415 patients (192 female and 223 male, mean age 37.2 years; 41% left-sided lesions and 84.9% temporal epileptogenic zones). The mean preoperative duration of epilepsy was 17.5 years. The most common epilepsy-associated pathologies included hippocampal sclerosis (n = 146 [35.2%]), long-term epilepsy-associated tumor (LEAT) (n = 67 [16.1%]), cavernoma (n = 45 [10.8%]), focal cortical dysplasia (n = 31 [7.5%]), and epilepsy caused by scar tissue (n = 23 [5.5%]). RESULTS In 11.8% (n = 49) of the surgeries, an intraoperative second-look surgery (SLS) after incomplete resection verified by iMRI had to be performed. Of those incomplete resections, LEATs were involved most often (40.8% of intraoperative SLSs, 29.9% of patients with LEAT). In addition, 37.5% (6 of 16) of patients in the diffuse glioma group and 12.9% of the patients with focal cortical dysplasia underwent an SLS. Moreover, iMRI provided additional advantages during implantation of grid, strip, and depth electrodes and enabled intraoperative correction of electrode position in 13.0% (3 of 23) of the cases. Altogether, an excellent seizure outcome (Engel Class I) was found in 72.7% of the patients during a mean follow-up of 36 months (range 3 months to 10.8 years). The greatest likelihood of an Engel Class I outcome was found in patients with cavernoma (83.7%), hippocampal sclerosis (78.8%), and LEAT (75.8%). Operative revisions that resulted from infection occurred in 0.3% of the patients, from hematomas in 1.6%, and from hydrocephalus in 0.8%. Severe visual field defects were found in 5.2% of the patients, aphasia in 5.7%, and hemiparesis in 2.7%, and the total mortality rate was 0%. CONCLUSIONS Neuronavigation combined with iMRI was beneficial during surgical procedures for epilepsy and led to favorable seizure outcome with few specific complications. A significantly higher resection volume associated with a higher chance of favorable seizure outcome was found, especially in lesional epilepsy involving LEAT or diffuse glioma.

scholarly journals Occult focal cortical dysplasia may predict poor outcome of surgery for drug-resistant mesial temporal lobe epilepsy

PLoS ONE ◽  
2021 ◽  
Vol 16 (9) ◽  
pp. e0257678
Author(s):  
Arkadiusz Nowak ◽  
Aleksandra Bala
Keyword(s):  
Temporal Lobe Epilepsy ◽  
Temporal Lobe ◽  
Focal Cortical Dysplasia ◽  
Mesial Temporal Lobe Epilepsy ◽  
Cortical Dysplasia ◽  
Class I ◽  
Seizure Outcome ◽  
Epileptogenic Zone ◽  
Dual Pathology ◽  
Mesial Temporal Lobe

Purpose The results of surgery in patients with mesial temporal lobe epilepsy (MTLE) associated with hippocampal sclerosis (HS) are favorable, with a success rate over 70% following resection. An association of HS with focal cortical dysplasia (FCD) in the temporal lobe is one of the potential causes for poor surgical outcome in MTLE. We aimed to analyzed seizure outcome in a population of MTLE patients and recognize the role of occult FCD in achieving postoperative seizure control. Methods We retrospectively analyzed postoperative outcomes for 82 consecutive adult patients with the syndrome of MTLE due to HS, who had no concomitant lesions within temporal lobe in MRI and who underwent surgical treatment in the years 2005–2016, and correlated factors associated with seizure relapse. Results At the latest follow-up evaluation after surgery, 59 (72%) were free of disabling seizures (Engel Class I) and 48 (58,5%) had an Engel Class Ia. HS associated with FCD in neocortical structures were noted in 33 patients (40%). Analyzes have shown that dual pathology was the most significant negative predictive factor for Engel class I and Engel class Ia outcome. Conclusions The incidence of dual pathology in patients with temporal lobe epilepsy seems to be underestimated. An incomplete epileptogenic zone resection of occult focal temporal dysplasia within temporal lobe is supposed to be the most important negative prognostic factor for seizure freedom after epilepsy surgery in MTLE-HS patients. The study indicates the need to improve diagnostics for other temporal lobe pathologies, despite the typical clinical and radiological picture of MTLE-HS.

Surgical treatment of intractable epilepsy associated with focal cortical dysplasia

2008 ◽  
Vol 25 (3) ◽  
pp. E6 ◽  
Author(s):  
Roberto Jose Diaz ◽  
Elisabeth M. S. Sherman ◽  
Walter J. Hader
Keyword(s):  
Refractory Epilepsy ◽  
Functional Neuroimaging ◽  
Focal Cortical Dysplasia ◽  
Intractable Epilepsy ◽  
Cortical Dysplasia ◽  
Complete Resection ◽  
Epileptogenic Zone ◽  
Malformations Of Cortical Development ◽  
Cortical Dysplasias

Focal cortical dysplasias (FCDs) are congenital malformations of cortical development that are a frequent cause of refractory epilepsy in both children and adults. With advances in structural and functional neuroimaging, these lesions are increasingly being identified as a cause of intractable epilepsy in patients undergoing surgical management for intractable epilepsy. Comprehensive histological classification of FCDs with the establishment of uniform terminology and reproducible pathological features has aided in our understanding of FCDs as an epilepsy substrate. Complete resection of FCDs and the associated epileptogenic zone can result in a good surgical outcome in the majority of patients.

Predictors of surgical outcome in focal cortical dysplasia and its subtypes

2021 ◽  
pp. 1-11
Author(s):  
Sita Jayalakshmi ◽  
Sudhindra Vooturi ◽  
Rammohan Vadapalli ◽  
Sailaja Madigubba ◽  
Manas Panigrahi
Keyword(s):  
Surgical Outcome ◽  
Focal Cortical Dysplasia ◽  
Cortical Dysplasia ◽  
Seizure Freedom ◽  
Type I ◽  
Incomplete Resection ◽  
Type Ii ◽  
Type Iii ◽  
Clear Cut

OBJECTIVE The authors analyzed predictors of surgical outcome in patients with focal cortical dysplasia (FCD) and its ILAE (International League Against Epilepsy) subtypes after noninvasive multimodal evaluation and calculated time to first seizure. METHODS Data of 355 patients with refractory epilepsy, confirmed FCD pathology, and 2–13 years of postsurgical follow-up were analyzed to determine the predictive roles of clinical, EEG, imaging, and surgical factors that influence seizure freedom. RESULTS The mean ± SD age at surgery was 20.26 ± 12.18 years. In total, 142 (40.0%) patients had daily seizures and 90 (25.3%) had multiple seizure types. MRI showed clear-cut FCD in 289 (81.4%) patients. Pathology suggested type I FCD in 27.3% of patients, type II in 28.4%, and type III in 42.8% of patients. At latest follow-up, 72.1% of patients were seizure free and 11.8% were seizure free and not receiving antiepileptic drugs. Among the subtypes, 88.8% of patients with type III, 69.3% with type II, and 50.5% with type I FCD were seizure free. Multiple seizure types, acute postoperative seizures (APOS), and type I FCD were predictors of persistent seizures, whereas type III FCD was the strongest predictor of seizure freedom. Type I FCD was associated with daily seizures, frontal and multilobar distribution, subtle findings on MRI, incomplete resection, and persistent seizures. Type II and III FCD were associated with clear-cut lesion on MRI, regional interictal and ictal EEG onset pattern, focal pattern on ictal SPECT, complete resection, and seizure freedom. Type III FCD was associated with temporal location, whereas type I and II FCD were associated with extratemporal location. Nearly 80% of patients with persistent seizures, mostly those with type I FCD, had their first seizure within 6 months postsurgery. CONCLUSIONS Long-term seizure freedom after surgery can be achieved in more than two-thirds of patients with FCD after noninvasive multimodal evaluation. Multiple seizure types, type I FCD, and APOS were predictors of persistent seizures. Seizures recurred in about 80% of patients within 6 months postsurgery.

Surgical Strategy and Outcomes for Epileptic Patients with Focal Cortical Dysplasia or Dysembryoplastic Neuroepithelial Tumor

Epilepsia ◽  
2001 ◽  
Vol 42 (s6) ◽  
pp. 37-41 ◽  
Author(s):  
Shigeki Kameyama ◽  
Masafumi Fukuda ◽  
Masaru Tomikawa ◽  
Nobuhito Morota ◽  
Makoto Oishi ◽  
...  
Keyword(s):  
Focal Cortical Dysplasia ◽  
Cortical Dysplasia ◽  
Surgical Strategy ◽  
Dysembryoplastic Neuroepithelial Tumor ◽  
Epileptic Patients

scholarly journals Surgical Strategy and Outcomes for Epileptic Patients with Focal Cortical Dysplasia or Dysembryoplastic Neuroepithelial Tumor

Epilepsia ◽  
2008 ◽  
Vol 42 ◽  
pp. 37-41 ◽  
Author(s):  
Shigeki Kameyama ◽  
Masafumi Fukuda ◽  
Masaru Tomikawa ◽  
Nobuhito Morota ◽  
Makoto Oishi ◽  
...  
Keyword(s):  
Focal Cortical Dysplasia ◽  
Cortical Dysplasia ◽  
Surgical Strategy ◽  
Dysembryoplastic Neuroepithelial Tumor ◽  
Epileptic Patients

scholarly journals Somatic mutation involving diverse genes leads to a spectrum of focal cortical malformations

2021 ◽  
Author(s):  
Dulcie Lai ◽  
Meethila Gade ◽  
Edward Yang ◽  
Hyun Yong Koh ◽  
Nicole M. Walley ◽  
...  
Keyword(s):  
Focal Cortical Dysplasia ◽  
Hippocampal Sclerosis ◽  
Cortical Development ◽  
Copy Number Variants ◽  
Cortical Dysplasia ◽  
Disease Genes ◽  
Type I ◽  
Type Ii ◽  
Loss Of Function ◽  
Brain Malformations

Post-zygotically acquired genetic variants, or somatic variants, that arise during cortical development have emerged as important causes of focal epilepsies, particularly those due to malformations of cortical development. Pathogenic somatic variants have been identified in many genes within the PI3K-AKT3-mTOR-signaling pathway in individuals with hemimegalencephaly and focal cortical dysplasia (type II), and more recently in SLC35A2 in individuals with focal cortical dysplasia (type I) or non-dysplastic epileptic cortex. Given the expanding role of somatic variants across different brain malformations, we sought to delineate the landscape of somatic variants in a large cohort of patients who underwent epilepsy surgery with hemimegalencephaly or focal cortical dysplasia. We evaluated samples from 123 children with hemimegalencephaly (n=16), focal cortical dysplasia type I and related phenotypes (n=48), focal cortical dysplasia type II (n=44), or focal cortical dysplasia type III (n=15) classified using imaging and pathological findings. We performed high-depth exome sequencing in brain tissue-derived DNA from each case and identified somatic single nucleotide, indel, and large copy number variants. In 75% of individuals with hemimegalencephaly and 29% with focal cortical dysplasia type II, we identified pathogenic variants in PI3K-AKT-mTOR pathway genes. Four of 48 cases with focal cortical dysplasia type I (8%) had a likely pathogenic variant in SLC35A2. While no other gene had multiple disease-causing somatic variants across the focal cortical dysplasia type I cohort, four individuals in this group had a single pathogenic or likely pathogenic somatic variant in CASK, KRAS, NF1, and NIPBL, genes associated with neurodevelopmental disorders. No rare pathogenic or likely pathogenic somatic variants in any neurological disease genes like those identified in the focal cortical dysplasia type I cohort were found in 63 neurologically normal controls (P = 0.017), suggesting a role for these novel variants. We also identified a somatic loss-of-function variant in the known epilepsy gene, PCDH19, present in a very small number of alleles in the dysplastic tissue from a female patient with focal cortical dysplasia IIIa with hippocampal sclerosis. In contrast to focal cortical dysplasia type II, neither focal cortical dysplasia type I nor III had somatic variants in genes that converge on a unifying biological pathway, suggesting greater genetic heterogeneity compared to type II. Importantly, we demonstrate that FCD types I, II, and III, are associated with somatic gene variants across a broad range of genes, many associated with epilepsy in clinical syndromes caused by germline variants, as well as including some not previously associated with radiographically evident cortical brain malformations.

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