Focal Cortical Dysplasia Type Ⅲ Related Medically Refractory Epilepsy: MRI Findings and Potential Predictors of Surgery Outcome

This study aims to explore the relationship between neuropathologic and the post-surgical prognosis of focal cortical dysplasia (FCD) typed-Ⅲ-related medically refractory epilepsy. A total of 266 patients with FCD typed-Ⅲ-related medically refractory epilepsy were retrospectively studied. Presurgical clinical data, type of surgery, and postsurgical seizure outcome were analyzed. The minimum post-surgical follow-up was 1 year. A total of 266 patients of FCD type Ⅲ were included in this study and the median follow-up time was 30 months (range, 12~48 months). Age at onset ranged from 1.0 years to 58.0 years, with a median age of 12.5 years. The number of patients under 12 years old was 133 (50%) in patients with FCD type Ⅲ. A history of febrile seizures was present in 42 (15.8%) cases. In the entire postoperative period, 179 (67.3%) patients were seizure-free. Factors with p < 0.15 in univariate analysis, such as age of onset of epilepsy (p = 0.145), duration of epilepsy (p = 0.004), febrile seizures (p = 0.150), being MRI-negative (p = 0.056), seizure type (p = 0.145) and incomplete resection, were included in multivariate analysis. Multivariate analyses revealed that MRI-negative findings of FCD (OR 0.34, 95% CI 0.45–0.81, p = 0.015) and incomplete resection (OR 0.12, 95% CI 0.05–0.29, p < 0.001) are independent predictors of unfavorable seizure outcomes. MRI-negative finding of FCD lesions and incomplete resection were the most important predictive factors for poor seizure outcome in patients with FCD type Ⅲ.

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Periinsular anterior quadrantotomy: technical note

Journal of Neurosurgery Pediatrics ◽

10.3171/2017.8.peds17339 ◽

2018 ◽

Vol 21 (2) ◽

pp. 124-132 ◽

Cited By ~ 3

Author(s):

Giulia Cossu ◽

Sebastien Lebon ◽

Margitta Seeck ◽

Etienne Pralong ◽

Mahmoud Messerer ◽

...

Keyword(s):

Frontal Lobe ◽

Refractory Epilepsy ◽

Focal Cortical Dysplasia ◽

Seizure Outcome ◽

Illustrative Case ◽

Neural Pathways ◽

Functional Neuroanatomy ◽

The Right ◽

Epileptogenic Foci

Refractory frontal lobe epilepsy has been traditionally treated through a frontal lobectomy. A disconnective technique may allow similar seizure outcomes while avoiding the complications associated with large brain resections. The aim of this study was to describe a new technique of selective disconnection of the frontal lobe that can be performed in cases of refractory epilepsy due to epileptogenic foci involving 1 frontal lobe (anterior to the motor cortex), with preservation of motor function. In addition to the description of the technique, an illustrative case is also presented.This disconnective procedure is divided into 4 steps: the suprainsular window, the anterior callosotomy, the intrafrontal disconnection, and the frontobasal disconnection. The functional neuroanatomy is analyzed in detail for each step of the surgery. It is important to perform cortical and subcortical electrophysiological mapping to guide this disconnective procedure and identify eloquent cortices and intact neural pathways.The authors describe the case of a 9-year-old boy who presented with refractory epilepsy due to epileptogenic foci localized to the right frontal lobe. MRI confirmed the presence of a focal cortical dysplasia of the right frontal lobe. A periinsular anterior quadrant disconnection (quadrantotomy) was performed. The postoperative period was uneventful, and the patient was in Engel seizure outcome Class I at the 3-year follow-up. A significant cognitive gain was observed during follow-up.Periinsular anterior quadrantotomy may thus represent a safe technique to efficiently treat refractory epilepsy when epileptogenic foci are localized to 1 frontal lobe while preserving residual motor functions.

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Cortical Dyplasia: Complete Resection Correlates with Outcome…But, Complete Resection of What?

Epilepsy Currents ◽

10.1111/j.1535-7511.2009.01306.x ◽

2009 ◽

Vol 9 (4) ◽

pp. 100-102 ◽

Cited By ~ 2

Author(s):

Theodore H. Schwartz

Keyword(s):

Fdg Pet ◽

Pediatric Patients ◽

Focal Cortical Dysplasia ◽

Cortical Dysplasia ◽

Seizure Outcome ◽

Type I ◽

Type Ii ◽

Presurgical Evaluation ◽

Mri Scans

Incomplete Resection of Focal Cortical Dysplasia Is the Main Predictor of Poor Postsurgical Outcome. Krsek P, Maton B, Jayakar P, Dean P, Korman B, Rey G, Dunoyer C, Pacheco-Jacome E, Morrison G, Ragheb J, Vinters HV, Resnick T, Duchowny M. Neurology 2009;72(3):217–223. BACKGROUND: Focal cortical dysplasia (FCD) is recognized as the major cause of focal intractable epilepsy in childhood. Various factors influencing postsurgical seizure outcome in pediatric patients with FCD have been reported. OBJECTIVE: To analyze different variables in relation to seizure outcome in order to identify prognostic factors for selection of pediatric patients with FCD for epilepsy surgery. METHODS: A cohort of 149 patients with histologically confirmed mild malformations of cortical development or FCD with at least 2 years of postoperative follow-up was retrospectively studied; 113 subjects had at least 5 years of postoperative follow-up. Twenty-eight clinical, EEG, MRI, neuropsychological, surgical, and histopathologic parameters were evaluated. RESULTS: The only significant predictor of surgical success was completeness of surgical resection, defined as complete removal of the structural MRI lesion (if present) and the cortical region exhibiting prominent ictal and interictal abnormalities on intracranial EEG. Unfavorable surgical outcomes are mostly caused by overlap of dysplastic and eloquent cortical regions. There were nonsignificant trends toward better outcomes in patients with normal intelligence, after hemispherectomy and with FCD type II. Other factors such as age at seizure onset, duration of epilepsy, seizure frequency, associated pathologies including hippocampal sclerosis, extent of EEG and MRI abnormalities, as well as extent and localization of resections did not influence outcome. Twenty-five percent of patients changed Engel's class of seizure outcome after the second postoperative year. CONCLUSIONS: The ability to define and fully excise the entire region of dysplastic cortex is the most powerful variable influencing outcome in pediatric patients with focal cortical dysplasia. FDG-PET/MRI Coregistration Improves Detection of Cortical Dysplasia in Patients with Epilepsy. Salamon N, Kung J, Shaw SJ, Koo J, Koh S, Wu JY, Lerner JT, Sankar R, Shields WD, Engel J Jr, Fried I, Miyata H, Yong WH, Vinters HV, Mathern GW. Neurology 2008;71(20):1594–1601. OBJECTIVE: Patients with cortical dysplasia (CD) are difficult to treat because the MRI abnormality may be undetectable. This study determined whether fluorodeoxyglucose (FDG)-PET/MRI coregistration enhanced the recognition of CD in epilepsy surgery patients. METHODS: Patients from 2004–2007 in whom FDG-PET/MRI coregistration was a component of the presurgical evaluation were compared with patients from 2000–2003 without this technique. For the 2004–2007 cohort, neuroimaging and clinical variables were compared between patients with mild Palmini type I and severe Palmini type II CD. RESULTS: Compared with the 2000–2003 cohort, from 2004–2007 more CD patients were detected, most had type I CD, and fewer cases required intracranial electrodes. From 2004–2007, 85% of type I CD cases had normal non–University of California, Los Angeles (UCLA) MRI scans. UCLA MRI identified CD in 78% of patients, and 37% of type I CD cases had normal UCLA scans. EEG and neuroimaging findings were concordant in 52% of type I CD patients, compared with 89% of type II CD patients. FDG-PET scans were positive in 71% of CD cases, and type I CD patients had less hypometabolism compared with type II CD patients. Postoperative seizure freedom occurred in 82% of patients, without differences between type I and type II CD cases. CONCLUSIONS: Incorporating fluorodeoxyglucose-PET/MRI coregistration into the multimodality presurgical evaluation enhanced the noninvasive identification and successful surgical treatment of patients with cortical dysplasia (CD), especially for the 33% of patients with nonconcordant findings and those with normal MRI scans from mild type I CD.

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Long-term outcomes of epilepsy surgery in 85 pediatric patients followed up for over 10 years: a retrospective survey

Journal of Neurosurgery Pediatrics ◽

10.3171/2016.12.peds16197 ◽

2017 ◽

Vol 19 (5) ◽

pp. 606-615 ◽

Cited By ~ 18

Author(s):

Hiroshi Hosoyama ◽

Kazumi Matsuda ◽

Tadahiro Mihara ◽

Naotaka Usui ◽

Koichi Baba ◽

...

Keyword(s):

Treatment Outcome ◽

Antiepileptic Drugs ◽

Epilepsy Surgery ◽

Social Engagement ◽

Focal Cortical Dysplasia ◽

Cortical Dysplasia ◽

Seizure Outcome ◽

Neoplastic Lesions ◽

The Mean

OBJECTIVEThe aim of this study was to investigate the treatment outcomes and social engagement of patients who had undergone pediatric epilepsy surgery more than 10 years earlier.METHODSBetween 1983 and 2005, 110 patients younger than 16 years underwent epilepsy surgery at the National Epilepsy Center, Shizuoka Institute of Epilepsy and Neurological Disorders. The authors sent a questionnaire to 103 patients who had undergone follow-up for more than 10 years after surgery; 85 patients (82.5%) responded. The survey contained 4 categories: seizure outcome, use of antiepileptic drugs, social participation, and general satisfaction with the surgical treatment (resection of the epileptic focus, including 4 hemispherectomies). The mean patient age at the time of surgery was 9.8 ± 4.2 (SD) years, and the mean duration of postoperative follow-up was 15.4 ± 5.0 years. Of the 85 patients, 79 (92.9%) presented with a lesional pathology, such as medial temporal sclerosis, developmental/neoplastic lesions, focal cortical dysplasia, and gliosis in a single lobe.RESULTSFor 65 of the 85 responders (76.5%), the outcome was recorded as Engel Class I (including 15 [93.8%] of 16 patients with medial temporal sclerosis, 20 [80.0%] of 25 with developmental/neoplastic lesions, and 27 [73.0%] of 37 with focal cortical dysplasia). Of these, 29 (44.6%) were not taking antiepileptic drugs at the time of our survey, 29 (44.6%) held full-time jobs, and 33 of 59 patients (55.9%) eligible to drive had a driver's license. Among 73 patients who reported their degree of satisfaction, 58 (79.5%) were very satisfied with the treatment outcome.CONCLUSIONSThe seizure outcome in patients who underwent resective surgery in childhood and underwent followup for more than 10 years was good. Of 85 respondents, 65 (76.5%) were classified in Engel Class I. The degree of social engagement was relatively high, and the satisfaction level with the treatment outcome was also high. From the perspective of seizure control and social adaptation, resective surgery yielded longitudinal benefits in children with intractable epilepsy, especially those with a lesional pathology in a single lobe.

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

Neurosurgical FOCUS ◽

10.3171/2015.12.focus15554 ◽

2016 ◽

Vol 40 (3) ◽

pp. E15 ◽

Cited By ~ 19

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.

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Focal cortical dysplasia: a review of pathological features, genetics, and surgical outcome

Neurosurgical FOCUS ◽

10.3171/foc.2006.20.1.8 ◽

2006 ◽

Vol 20 (1) ◽

pp. 1-7 ◽

Cited By ~ 30

Author(s):

Vincent Y. Wang ◽

Edward F. Chang ◽

Nicholas M. Barbaro

Keyword(s):

Molecular Biology ◽

Surgical Outcome ◽

Refractory Epilepsy ◽

Focal Cortical Dysplasia ◽

Cortical Dysplasia ◽

Pathological Features ◽

Balloon Cells ◽

Medically Refractory Epilepsy

Focal cortical dysplasia (FCD) is found in approximately one-half of patients with medically refractory epilepsy. These lesions may involve only mild disorganization of the cortex, but they may also contain abnormal neuronal elements such as balloon cells. Advances in neuroimaging have allowed better identification of these lesions, and thus more patients have become surgical candidates. Molecular biology techniques have been used to explore the genetics and pathophysiological characteristics of FCD. Data from surgical series have shown that surgery often results in significant reduction or cessation of seizures, especially if the entire lesion is resected.

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Surgical outcome for focal cortical dysplasia: an analysis of recent surgical series

Journal of Neurosurgery Pediatrics ◽

10.3171/2010.8.peds10145 ◽

2010 ◽

Vol 6 (5) ◽

pp. 452-458 ◽

Cited By ~ 24

Author(s):

Joshua J. Chern ◽

Akash J. Patel ◽

Andrew Jea ◽

Daniel J. Curry ◽

Youssef G. Comair

Keyword(s):

Functional Imaging ◽

Surgical Outcome ◽

Focal Cortical Dysplasia ◽

Intractable Epilepsy ◽

Cortical Dysplasia ◽

Prognostic Indicators ◽

Seizure Outcome ◽

Clinical Presentations ◽

Number Of Patients ◽

Selection For

Object Focal cortical dysplasia (FCD) is an important cause of intractable epilepsy and is at times treatable by resection. The now widespread use of MR imaging and recent advancement of functional imaging have increased the number of patients undergoing surgical treatment for FCD. The objective of this review is to critically examine and to provide a summary of surgical series on FCD published since 2000. Methods Studies concerning surgery for FCD were identified from MEDLINE and references of selected articles and book chapters. Data from these included studies were summarized and analyzed to identify factors correlated with seizure outcome. Results Sixteen studies were identified, and 469 patients met our selection criteria. Seizure-free outcome at 1-year postoperatively was achieved in 59.7% of the patients. Children and adults were equally likely to benefit from the surgery. Complete resection (OR 13.7, 95% CI 6.68–28.1; p < 0.0001) and temporal location (OR 2.15, 95% CI 1.26–3.69; p = 0.0073) were two positive prognostic indicators of seizure-free outcome. Utilization of invasive monitoring did not affect the chance of seizure remission, but firm conclusions could not be drawn because patients were not randomized. Conclusions The advancement of modern imaging has transformed the process of surgical candidate selection for partial epilepsy due to FCD. Patients from recent surgical series were more homogeneous in their clinical presentations and might represent FCD as an independent pathological entity. This likely explained the improved surgical outcome for this group of patients. These reports also documented the increased utilization of functional imaging, but their efficacy needs to be verified with further studies.

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Longitudinal analyses of the surgical outcomes of pediatric epilepsy patients with focal cortical dysplasia

Journal of Neurosurgery Pediatrics ◽

10.3171/2010.3.peds09497 ◽

2010 ◽

Vol 6 (1) ◽

pp. 49-56 ◽

Cited By ~ 38

Author(s):

Ji Hoon Phi ◽

Byung-Kyu Cho ◽

Kyu-Chang Wang ◽

Ji Yeoun Lee ◽

Yong Seung Hwang ◽

...

Keyword(s):

Surgical Outcomes ◽

Seizure Control ◽

Focal Cortical Dysplasia ◽

Cortical Dysplasia ◽

Significant Variable ◽

Incomplete Resection ◽

Longitudinal Analyses ◽

Control Failure

Object The long-term surgical outcome of pediatric patients with epilepsy accompanied by focal cortical dysplasia (FCD) is not clear. The authors report on the long-term surgical outcomes of children with FCD, based on longitudinal analyses. Methods The authors retrospectively analyzed the records of 41 children who underwent epilepsy surgery for pathologically proven FCD. Twenty of these patients were male and 21 were female. The median age at surgery was 9 years (range 1–17 years). Results The actuarial seizure-free rates were 49, 44, and 33% in the 1st, 2nd, and 5th years after surgery, respectively. There was no seizure recurrence after 3 years. Three patients with initial failure of seizure control experienced late remission of seizures (the so-called running-down phenomenon). Eventually, 19 patients (46%) were seizure free at their last follow-up visit. Absence of a lesion on MR imaging and incomplete resection were significantly associated with seizure-control failure. Concordance of presurgical evaluation data was a marginally significant variable for seizure control in patients with lesional epilepsy. Three patients with seizure-control failure became seizure free as a result of the running-down phenomenon. The actuarial rate of antiepileptic drug discontinuation was 91% in the 5th year in the seizure-free patients. Conclusions The seizure-free rate after surgery in children with FCD was 49% in the 1st year; however, it declined thereafter. The running-down phenomenon could be an important mechanism of seizure alleviation for patients with FCD during long-term follow-up. Because a complete resection of FCD has a strong prognostic implication for seizure control, a better method to define the extent of FCD is required to assist with resection, especially in nonlesional epilepsy.

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Focal Cortical Dysplasia IIIa in Hippocampal Sclerosis-Associated Epilepsy: Anatomo-Electro-Clinical Profile and Surgical Results From a Multicentric Retrospective Study

Neurosurgery ◽

10.1093/neuros/nyaa369 ◽

2020 ◽

Author(s):

Massimo Cossu ◽

Piergiorgio d'Orio ◽

Carmen Barba ◽

Sofia Asioli ◽

Francesco Cardinale ◽

...

Keyword(s):

Focal Cortical Dysplasia ◽

Hippocampal Sclerosis ◽

Cortical Dysplasia ◽

Clinical Profile ◽

Class I ◽

Seizure Outcome ◽

Surgical Results ◽

Postoperative Control ◽

Postoperative Seizure

Abstract BACKGROUND Hippocampal sclerosis (HS) may be associated with focal cortical dysplasia IIIa (FCD IIIa) in patients undergoing surgery for temporal lobe epilepsy (TLE). OBJECTIVE To investigate whether the anatomo-electro-clinical profile and surgical outcome in patients with HS-related TLE are affected by coexisting FCD IIIa. METHODS A total of 220 patients, operated in 5 centers, with at least 24 mo follow-up (FU), were retrospectively studied. Preliminary univariate and subsequent multivariate analyses were performed to investigate possible associations between several potential presurgical, surgical, and postsurgical predictors and different variables (Engel's class I and Engel's class Ia, co-occurrence of FCD IIIa). RESULTS At last available postoperative control (FU: range 24-95 mo, median 47 mo), 182 (82.7%) patients were classified as Engel's class I and 142 (64.5%) as Engel's class Ia. At multivariate analysis, extension of neocortical resection and postoperative electroencephalogram were significantly associated with Engel's class I, whereas length of FU had a significant impact on class Ia in the whole cohort and in isolated HS (iHS) patients, but not in the FCD IIIa group. No differences emerged in the anatomo-electro-clinical profile and surgical results between patients with FCD IIIa and with iHS. CONCLUSION Coexistence of FCD IIIa did not confer a distinct anatomo-electro-clinical profile to patients with HS-related epilepsy. Postoperative seizure outcome was similar in FCD IIIa and iHS cases. These findings indicate limited clinical relevance of FCD IIIa in HS-related epilepsy and might be useful for refining future FCD classifications. Further studies are needed to clarify the correlation of class Ia outcome with the duration of FU.

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Electroclinical and Multimodality Neuroimaging Characteristics and Predictors of Post-Surgical Outcome in Focal Cortical Dysplasia Type IIIa

Frontiers in Bioengineering and Biotechnology ◽

10.3389/fbioe.2021.810897 ◽

2022 ◽

Vol 9 ◽

Author(s):

Lingling Zhang ◽

Hailing Zhou ◽

Wei Zhang ◽

Xueying Ling ◽

Chunyuan Zeng ◽

...

Keyword(s):

Epilepsy Surgery ◽

Focal Cortical Dysplasia ◽

Univariate Analysis ◽

Postoperative Outcome ◽

Cortical Dysplasia ◽

Seizure Outcome ◽

Seizure Freedom ◽

Incomplete Resection ◽

Type Iiia ◽

Imaging Characteristics

Focal cortical dysplasia (FCD) type IIIa is an easily ignored cause of intractable temporal lobe epilepsy. This study aimed to analyze the clinical, electrophysiological, and imaging characteristics in FCD type IIIa and to search for predictors associated with postoperative outcome in order to identify potential candidates for epilepsy surgery. We performed a retrospective review including sixty-six patients with FCD type IIIa who underwent resection for drug-resistant epilepsy. We evaluated the clinical, electrophysiological, and neuroimaging features for potential association with seizure outcome. Univariate and multivariate analyses were conducted to explore their predictive role on the seizure outcome. We demonstrated that thirty-nine (59.1%) patients had seizure freedom outcomes (Engel class Ia) with a median postsurgical follow-up lasting 29.5 months. By univariate analysis, duration of epilepsy (less than 12 years) (p = 0.044), absence of contralateral insular lobe hypometabolism on PET/MRI (pLog-rank = 0.025), and complete resection of epileptogenic area (pLog-rank = 0.004) were associated with seizure outcome. The incomplete resection of the epileptogenic area (hazard ratio = 2.977, 95% CI 1.218–7.277, p = 0.017) was the only independent predictor for seizure recurrence after surgery by multivariate analysis. The results of past history, semiology, electrophysiological, and MRI were not associated with seizure outcomes. Carefully included patients with FCD type IIIa through a comprehensive evaluation of their clinical, electrophysiological, and neuroimaging characteristics can be good candidates for resection. Several preoperative factors appear to be predictive of the postoperative outcome and may help in optimizing the selection of ideal candidates to benefit from epilepsy surgery.

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Ultrasonographic features of focal cortical dysplasia and their relevance for epilepsy surgery

Neurosurgical FOCUS ◽

10.3171/2018.6.focus18221 ◽

2018 ◽

Vol 45 (3) ◽

pp. E5 ◽

Cited By ~ 3

Author(s):

Kevin Akeret ◽

David Bellut ◽

Hans-Jürgen Huppertz ◽

Georgia Ramantani ◽

Kristina König ◽

...

Keyword(s):

Refractory Epilepsy ◽

Diagnostic Yield ◽

Focal Cortical Dysplasia ◽

Intraoperative Ultrasound ◽

Cortical Dysplasia ◽

Added Value ◽

Seizure Outcome ◽

Type I ◽

Type Ii ◽

Drug Refractory Epilepsy

OBJECTIVESurgery has proven to be the best therapeutic option for drug-refractory cases of focal cortical dysplasia (FCD)–associated epilepsy. Seizure outcome primarily depends on the completeness of resection, rendering the intraoperative FCD identification and delineation particularly important. This study aims to assess the diagnostic yield of intraoperative ultrasound (IOUS) in surgery for FCD-associated drug-refractory epilepsy.METHODSThe authors prospectively enrolled 15 consecutive patients with drug-refractory epilepsy who underwent an IOUS-assisted microsurgical resection of a radiologically suspected FCD between January 2013 and July 2016. The findings of IOUS were compared with those of presurgical MRI postprocessing and the sonographic characteristics were analyzed in relation to the histopathological findings. The authors investigated the added value of IOUS in achieving completeness of resection and improving postsurgical seizure outcome.RESULTSThe neurosurgeon was able to identify the dysplastic tissue by IOUS in all cases. The visualization of FCD type I was more challenging compared to FCD II and the demarcation of its borders was less clear. Postsurgical MRI showed residual dysplasia in 2 of the 3 patients with FCD type I. In all FCD type II cases, IOUS allowed for a clear intraoperative visualization and demarcation, strongly correlating with presurgical MRI postprocessing. Postsurgical MRI confirmed complete resection in all FCD type II cases. Sonographic features correlated with the histopathological classification of dysplasia (sonographic abnormalities increase continuously in the following order: FCD IA/IB, FCD IC, FCD IIA, FCD IIB). In 1 patient with IOUS features atypical for FCD, histopathological investigation showed nonspecific gliosis.CONCLUSIONSMorphological features of FCD, as identified by IOUS, correlate well with advanced presurgical imaging. The resolution of IOUS was superior to MRI in all FCD types. The appreciation of distinct sonographic features on IOUS allows the intraoperative differentiation between FCD and non-FCD lesions as well as the discrimination of different histological subtypes of FCD. Sonographic demarcation depends on the underlying degree of dysplasia. IOUS allows for more tailored resections by facilitating the delineation of the dysplastic tissue.

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