Seizure Outcome After Surgery for MRI-Diagnosed Focal Cortical Dysplasia

Abstract

Objective:Focal cortical dysplasia (FCD) has been associated with poorer post-surgical seizure outcomes compared to other pathologies. FCD surgical series have been assembled on the basis of a histological diagnosis, including patients with abnormal as well as normal pre-operative MRI. However, in clinical workflow, patient selection for surgery is based on pre-operative findings, including MRI. We performed a systematic review and meta-analysis of the literature to determine the rate and predictors of favorable seizure outcome after surgery for MRI-detected FCD.Methods:We devised our study protocol in accordance with PRISMA guidelines and registered the protocol with PROSPERO. We searched MEDLINE, EMBASE, and Web of Science for studies of patients followed for ≥12 months after resective surgery for drug-resistant epilepsy with MRI-detected FCD. Random-effects meta-analysis was used to calculate the proportion of patients attaining a favorable outcome, defined as Engel Class I, ILAE Classes 1-2, or “seizure-free” status. Meta-regression was performed to investigate sources of heterogeneity.Results:Our search identified 3,745 references. Of these, 35 studies (total of 1,353 patients) were included. Most studies (89%) followed patients for ≥24 months post-surgery. The overall post-surgical favorable outcome rate was 70% (95% CI: 64-75). There was high inter-study heterogeneity. Favorable outcome was associated with complete resection of the FCD lesion [risk ratio, RR=2.42 (95% CI: 1.55-3.76), p<0.001] and location of the FCD lesion in the temporal lobe [RR=1.38 (95% CI: 1.07-1.79), p=0013], but not lesion extent, intracranial EEG use, or FCD histological type. The number of FCD histological types included in the same study accounted for 7.6% of the observed heterogeneity.Conclusions:70% of patients with drug-resistant epilepsy and MRI features of FCD attain a favorable seizure outcome following resective surgery. Our findings can be incorporated in routine pre-operative counselling and reinforce the importance of resecting completely the MRI-detected FCD where this is safe and feasible.

Prognostic analysis in children with focal cortical dysplasia II undergoing epilepsy surgery: Clinical and radiological factors

“…Persistent seizures in childhood, as well as the long-term usage of multiple antiepileptic drugs, have significant negative effects on children's growth, development, and cognitive functions. Previous studies have shown ( 5 – 7 ) that early surgery and the complete resection of the epileptogenic zone draw support from the plasticity of brain development to provide more opportunities for nerve cells to compensate, which is more beneficial for postoperative recovery and to improve the quality of life in children ( 16 ). We obtained consistent results from the analysis of clinical data that complete resection was beneficial for patient prognosis.…”

“…Previous research on the influencing factors of surgical outcomes in patients with intractable epilepsy due to FCD has mostly focused on the analysis of clinical indicators such as seizure forms, electroencephalography, and surgical approaches. A complete resection of the assumed epileptogenic area was the only well-established factor for a satisfactory prognosis ( 5 – 7 ). The radiological studies related to FCD have been mainly committed to the summary of MRI features ( 8 , 9 ).…”

Focal cortical dysplasia: a practical guide for neurologists

“…A systematic literature review and meta-analysis identified complete resection of the lesion and location of the FCD lesion in the temporal lobe as predictors of favourable seizure outcome after surgery for MRI-detected FCD. Lesion extent, intracranial EEG use, or FCD histological type were not associated with postsurgical outcome 64. Correlation between the underlying genetic aetiology and postsurgical outcome remains to be determined 9…”

“…Up to 70% of patients with FCD and drug-resistant epilepsy, including children with severe epileptic encephalopathies, achieve a favourable seizure outcome after surgery 25 64. A recent retrospective multicentre cohort study of >9000 patients who underwent epilepsy surgery between 2000 and 2012 described the following findings: seizure outcomes were worst for FCDI and mMCD, possibly due to more diffuse structural abnormalities and a difficult-to-delineate epileptogenic zone and, consequently, to incomplete resections; children had a similar prognosis regarding seizure outcome to adults, but more children stopped the medication; temporal lobe surgeries had the best seizure outcomes, and a longer duration of epilepsy was associated with reduced chances of favourable seizure outcomes and drug withdrawal 23.…”

D-galactose supplementation for the treatment of mild malformation of cortical development with oligodendroglial hyperplasia in epilepsy (MOGHE): a trial of precision medicine after epilepsy surgery

“…Resective surgery constitutes the rst-choice treatment for drug-resistant focal epilepsy due to FCD and other MCDs. The overall rate of favorable epilepsy outcome ranges between 64-70% at 12 months after surgery [3], [30], [31]. However, a signi cant proportion of MCD patients are not rendered seizure free after surgery.…”