Seizure Outcomes in Occipital Lobe and Posterior Quadrant Epilepsy Surgery: A Systematic Review and Meta-Analysis

Efficacy of neuromodulation of the pulvinar nucleus for drug-resistant epilepsy

OBJECTIVE

The pulvinar nucleus of the thalamus has extensive cortical connections with the temporal, parietal, and occipital lobes. Deep brain stimulation (DBS) targeting the pulvinar nucleus, therefore, carries the potential for therapeutic benefit in patients with drug-resistant posterior quadrant epilepsy (PQE) and neocortical temporal lobe epilepsy (TLE). Here, we present a single-center experience of patients managed via bilateral DBS of the pulvinar nucleus.

METHODS

A single-institution retrospective review of five patients who underwent bilateral pulvinar DBS for drug-resistant TLE or PQE was performed. Stimulation parameters were adjusted monthly as needed, and side effects were monitored. The primary outcome was the percentage reduction in patient-reported seizure frequency in comparison to the preimplant baseline. The location of the active electrode contacts in relation to pulvinar thalami that produced the best seizure outcome was identified. Chronic sensing of the pulvinar local field potentials (LFPs) and circadian pattern of modulation of the LFP amplitudes were analyzed.

RESULTS

Four patients (80%) experienced a >70% reduction in seizure frequency, whereas one patient had >50% reduction in seizure. Mean seizure reduction was 79% at a median follow-up of 13 months (range = 9-21 months). No significant side effects were noted. Of all the pulvinar subnuclei, stimulation of the medial pulvinar nucleus (MPN) produced the best seizure outcome in all patients except for two, in whom active contacts in the MPN but also in more lateral and inferior locations resulted in the most significant reduction in seizures. Chronic timeline data identified changes in LFP amplitude associated with stimulation and seizure occurrences.

SIGNIFICANCE

In this first ever report on a series of patients undergoing bilateral pulvinar DBS for drug-resistant epilepsy, we demonstrate that stimulation of the pulvinar and in particular the MPN is a safe and viable option for patients with nonlesional PQE or TLE. The optimal target for stimulation and relative merits of open versus closed loop stimulation should be delineated in future studies.

Occipital lobe epilepsy surgery: treating seizures in the posterior cortex

Occipital lobe epilepsy (OLE) is an uncommon type of extratemporal epilepsy constituting roughly 2-13% of symptomatic partial epilepsies and epilepsy surgery cases. Over two-thirds of patients with OLE present with two characteristics: (1) ictal semiology compatible with an occipital seizure focus (e.g., ictal blindness, visual perceptual disturbance, eye blinking, nystagmus), and (2) lateralizing features referable to the posterior cortex (e.g., visual field defects, contralateral head deviation). The remaining one-third of patients present with ≥ 2 seizure types, indicative of spread to other lobes. A common representation of this cortical spread is the altered mental status and generalized tonic-clonic activity seen in patient with OLE. While the key clinical symptoms include visual hallucinations, it may be difficult to elicit on history, especially from children, and are not always present.

Seizing Control: Primary Visual Cortex Epilepsy Treated With Resection and Responsive Neurostimulation: 2-Dimensional Operative Video

Occipital lobe epilepsy is a debilitating condition, and surgical resection has been effective, though challenges arise because of the cortex's function. 1-7 Approximately 57% of patients with normal vision experience new visual field deficits postoperatively. 8 A combined approach of resection and responsive neurostimulation (RNS) could aid in decreasing the visual field area severed and the disability tied to it while obtaining seizure freedom. 9,10 We aimed to present a case of medically refractory occipital lobe epilepsy with involvement of the primary visual cortex treated with a combined approach. The patient consented to the procedure and to the publication of his image. Any identifiable individuals consented to publication of his/her image.

A 21-year-old right-handed male experienced refractory epilepsy since age 1 year. His first seizure was a severe refractory status epilepticus which resulted in cardiac arrest. His usual seizure semiology exhibited focal impaired awareness to bilateral tonic-clonic seizures occurring monthly. Noninvasive tests did not provide precise localization, but the intracranial electroencephalogram confirmed seizure onset in the right cuneus with rapid spread to the lingual gyrus and the superior parietal lobe. We performed a corticectomy 11 of the seizure onset zone and used RNS to address spreading areas in the parietal and occipital lobe. A complete lobectomy was avoided to prevent postoperative homonymous hemianopsia in a previously intact patient. The patient was discharged on postoperative day 3 with a nondisabling left inferior quadrantanopia. No clinical seizures were detected after RNS was turned on, rendering so far 8.5 months of seizure freedom.

The combined surgical approach appears promising for medically refractory epilepsy involving functional areas.

Surgical outcomes following resection in patients with language dominant posterior quadrant epilepsy

Posterior quadrant epilepsy surgery, involving the occipital lobe, parietal lobe, or the posterior border of the temporal lobe, accounts for a small percentage of focal resections for medically refractory epilepsy. Prior studies investigating seizure control from posterior quadrant epilepsy surgery are limited. In this study, a retrospective database of patients undergoing surgery for left sided posterior cortex epilepsy at a single large level 4 epilepsy center was analyzed between August 2008 to April 2021 in order to characterize seizure control outcomes. Nine patients presented with epileptogenic foci in the left posterior cortex with a malformation of cortical development deemed as the etiology of seizures for all but one patient. Absolute seizure freedom (Engel I) was achieved in 4 of 9 patients, with the remaining 5 patients achieving an improvement in the frequency of seizures (Engel II/III). Complete resection of the anatomic and physiologic abnormalities was performed in 3 of 4 patients with Engel 1 outcomes and 1 of 5 patients with Class II/III outcomes. Five patients developed new right sided visual field defects, all of which were expected based on the sub-lobar, occipital localization and were viewed as acceptable by the patients and did not interfere with activities of daily living. Overall, our study demonstrates the potential for surgical resection to yield excellent seizure-control outcomes with anticipated, tolerable neurological deficits. This information is important for patients with disabling seizures who may not benefit sufficiently from palliative procedures.

Bevacizumab is associated with cerebral microstructural alterations: a DTI study in high-grade glioma

Background

For recurrent high-grade glioma, especially glioblastoma, no standard of care treatment exists. Due to the prolongation of progression-free survival and a cortiocosteroid-sparing effect, bevacizumab is often used in this condition. Despite initial clinical responses, there is growing evidence that bevacizumab may potentiate microstructural alterations which may cause cognitive decline, mostly affecting learning and memory.

Methods

To investigate bevacizumab-associated microstructural damage of defined regions of interest (ROIs) in the white matter, diffusion tensor imaging (DTI) was performed in 10 patients with a case history or third-party report for neurological dysfunction concerning cognitive performance. Serial DTI data before and under bevacizumab were collected and longitudinal changes of fractional anisotropy (FA), axial diffusivity (AD), and radial diffusivity (RD) were assessed in mesiotemporal (hippocampal), frontal, and occipital regions.

Results

The longitudinal DTI data under bevacizumab compared to DTI prior to bevacizumab demonstrated a significant decrease in FA and increase in AD and RD both in mesiotemporal (hippocampal) regions and in frontal regions, whereas occipital regions showed no significant alterations in DTI metrics.

Conclusion

The regionally impaired microstructure in mesiotemporal (hippocampal) regions and in frontal regions is in line with the fact that neurocognitive impairment in learning and memory is mostly related to hippocampal integrity and attentional control in frontal regions. Further studies could investigate the potential of DTI to assess bevacizumab-associated microstructural damages in vulnerable brain regions.

Outcome Predictors of Lesional Posterior Cortex Epilepsy Surgery

BACKGROUND

Lesional posterior cortex epilepsy (PCE) is often drug resistant and may benefit from surgical intervention. In this study, we aimed to identify potential predictive factors associated with seizure recurrence after epilepsy surgery in lesional PCE.

METHODS

We retrospectively reviewed patients with PCE who underwent surgery between 1998 and 2021. They were divided into 2 groups according to seizure outcome; the seizure-free group (group 1) and the non-seizure-free group (group 2). The relationship among clinical factors, electroencephalography (EEG) or cranial magnetic resonance imaging findings, disease, and seizure outcome was investigated.

RESULTS

A total of 60 patients, with a mean age of 27.26 ± 12.35 years (range, 9-61 years), were included in the study. There were 31 patients (51.66%) in group 1 (Engel class I) and 29 patients (48.33%) in group 2 (13 [21.66%], 10 [16.66%], and 6 [10%] patients in Engel class II, III, and IV, respectively), with a mean follow-up of 8.95 ± 6.96 years (range, 1-24 years). No difference was observed regarding age, gender, age at seizure onset, operation type, treatment gap, and presence of bilateral lesions between the groups (P > 0.05). However, bilateral findings on interictal EEG and gliosis as the underlying disease were predictors of seizure recurrence (P < 0.05).

CONCLUSIONS

More than half of the patients (including 2 with bilateral magnetic resonance imaging lesions) were seizure free at long-term follow-up. However, patients with bilateral findings on interictal EEG and gliosis were more likely to have recurrent seizures after surgery. Because lesional PCE is almost always drug resistant and has a potential for favorable outcomes, epilepsy surgery should be considered early.

Predictors of outcomes after surgery for medically intractable insular epilepsy: A systematic review and individual participant data meta-analysis

Insular epilepsy (IE) is an increasingly recognized cause of drug-resistant epilepsy amenable to surgery. However, concerns of suboptimal seizure control and permanent neurological morbidity hamper widespread adoption of surgery for IE. We performed a systematic review and individual participant data meta-analysis to determine the efficacy and safety profile of surgery for IE and identify predictors of outcomes. Of 2483 unique citations, 24 retrospective studies reporting on 312 participants were eligible for inclusion. The median follow-up duration was 2.58 years (range, 0-17 years), and 206 (66.7%) patients were seizure-free at last follow-up. Younger age at surgery (≤18 years; HR = 1.70, 95% CI = 1.09-2.66, P = .022) and invasive EEG monitoring (HR = 1.97, 95% CI = 1.04-3.74, P = .039) were significantly associated with shorter time to seizure recurrence. Performing MR-guided laser ablation or radiofrequency ablation instead of open resection (OR = 2.05, 95% CI = 1.08-3.89, P = .028) was independently associated with suboptimal or poor seizure outcome (Engel II-IV) at last follow-up. Postoperative neurological complications occurred in 42.5% of patients, most commonly motor deficits (29.9%). Permanent neurological complications occurred in 7.8% of surgeries, including 5% and 1.4% rate of permanent motor deficits and dysphasia, respectively. Resection of the frontal operculum was independently associated with greater odds of motor deficits (OR = 2.75, 95% CI = 1.46-5.15, P = .002). Dominant-hemisphere resections were independently associated with dysphasia (OR = 13.09, 95% CI = 2.22-77.14, P = .005) albeit none of the observed language deficits were permanent. Surgery for IE is associated with a good efficacy/safety profile. Most patients experience seizure freedom, and neurological deficits are predominantly transient. Pediatric patients and those requiring invasive monitoring or undergoing stereotactic ablation procedures experience lower rates of seizure freedom. Transgression of the frontal operculum should be avoided if it is not deemed part of the epileptogenic zone. Well-selected candidates undergoing dominant-hemisphere resection are more likely to exhibit transient language deficits; however, the risk of permanent deficit is very low.

Elucidating the visual phenomena in epilepsy: A mini review

Epilepsy is one of the most recognizable neurological diseases, globally. Epilepsy may be accompanied by various complications, including vision impairments, which may severely impact one's quality of life. These visual phenomena may occur in the preictal, ictal and/or postictal periods of seizures. Examples of epilepsy associated visual phenomena include visual aura, visual hallucinations, transient visual loss and amaurosis (blindness). These ophthalmologic signs/symptoms of epilepsy may be temporary or permanent and may vary depending of the type of epilepsy and location of the seizure foci (occipital or temporal lobe). Some visual phenomena may even be utilized to diagnose the epilepsy type, although solely depending on visual symptoms for diagnosis may lead to mistreatment. Some antiseizure medications (ASMs) may also contribute to certain visual disturbances, thereby impacting its therapeutic efficiency for patients with epilepsy (PWE). Although the development of visual comorbidities has been observed diversely among PWE, there may still be a lack of understanding on their relevance and manifestation in epilepsy, which may contribute to the rate of misdiagnosis and the current scarcity in therapeutic relieve. Therefore, this mini narrative review aimed to discuss the common epilepsy associated visual phenomena, based on the available literature. This review also showcased the relationship between the type of visual complications and the site of seizure onset, as well as compared the visual phenomena between occipital lobe epilepsy and temporal lobe epilepsy. Evaluation of these findings may be crucial in reducing the risk of permanent seizure/epilepsy related vision deficits among PWE.

Clinical Impacts of Stereotactic Electroencephalography on Epilepsy Surgery and Associated Issues in the Current Situation in Japan

Stereotactic electroencephalography (SEEG) is receiving increasing attention as a safe and effective technique in the invasive evaluation for epileptogenic zone (EZ) detection. The main clinical question is whether the use of SEEG truly improves outcomes. Herein, we compared outcomes in our patients after three types of intracranial EEG (iEEG): SEEG, the subdural electrode (SDE), and a combined method using depth and strip electrodes. We present here our preliminary results from two demonstrative cases. Several international reports from large epilepsy centers found the following clinical advantages of SEEG: 1) three-dimensional analysis of structures, including bilateral and multilobar structures; 2) low rate of complications; 3) less pneumoencephalopathy and less patient burden during postoperative course, which allows the initiation of video-EEG monitoring immediately after implantation and does not require resection to be performed in the same hospitalization; and 4) a higher rate of good seizure control after resection. In other words, SEEG more accurately identified the EZ than the SDE method. We obtained similar results in our preliminary experiences under limited conditions. In Japan, as of August 2022, dedicated electrodes and SEEG accessories have not been approved and the use of the robot arm is not widespread. The Japanese medical community is hopeful that these issues will soon be resolved and that the experience with SEEG in Japan will align with that of large epilepsy centers internationally.

Impact of intraoperative direct cortical stimulation dynamics on perioperative seizures and afterdischarge frequency in patients undergoing awake craniotomy

OBJECTIVE

Intraoperative stimulation is used as a crucial adjunct in neurosurgical oncology, allowing for greater extent of resection while minimizing morbidity. However, limited data exist regarding the impact of cortical stimulation on the frequency of perioperative seizures in these patients.

METHODS

A retrospective chart review of patients undergoing awake craniotomy with electrocorticography data by a single surgeon at the authors' institution between 2013 and 2020 was conducted. Eighty-three patients were identified, and electrocorticography, stimulation, and afterdischarge (AD)/seizure data were collected and analyzed. Stimulation characteristics (number, amplitude, density [stimulations per minute], composite score [amplitude × density], total and average stimulation duration, and number of positive stimulation sites) were analyzed for association with intraoperative seizures (ISs), ADs, and postoperative clinical seizures.

RESULTS

Total stimulation duration (p = 0.005), average stimulation duration (p = 0.010), and number of stimulations (p = 0.020) were found to significantly impact AD incidence. A total stimulation duration of more than 145 seconds (p = 0.04) and more than 60 total stimulations (p = 0.03) resulted in significantly higher rates of ADs. The total number of positive stimulation sites was associated with increased IS (p = 0.048). Lesions located within the insula (p = 0.027) were associated with increased incidence of ADs. Patients undergoing repeat awake craniotomy were more likely to experience IS (p = 0.013). Preoperative antiepileptic drug use, seizure history, and number of prior resections of any type showed no impact on the outcomes considered. The charge transferred to the cortex per second during mapping was significantly higher in the 10 seconds leading to AD than at any other time point examined in patients experiencing ADs, and was significantly higher than any time point in patients not experiencing ADs or ISs. Although the rate of transfer for patients experiencing ISs was highest in the 10 seconds prior to the seizure, it was not significantly different from those who did not experience an AD or IS.

CONCLUSIONS

The data suggest that intraoperative cortical stimulation is a safe and effective technique in maximizing extent of resection while minimizing neurological morbidity in patients undergoing awake craniotomies, and that surgeons may avoid ADs and ISs by minimizing duration and total number of stimulations and by decreasing the overall charge transferred to the cortex during mapping procedures.

Paediatric epilepsy surgery: Techniques and outcomes

Epilepsy is a neurological condition characterised by recurrent and persistent seizures. For paediatric patients, achieving early seizure freedom can have positive impacts on cognition, development, social integration and mental health, leading to improved quality of life. In general, one third of patients with epilepsy are refractory to medication; for these patients, epilepsy surgery may offer the only chance for improved seizure control. Epilepsy surgery as a therapeutic intervention has become increasingly accepted in the past few decades, with more diverse options available (including neuromodulatory and minimally invasive techniques). In this context, we discuss here the pre-operative workup for paediatric patients with medically refractory epilepsy and provide an updated review on current and emerging surgical therapies for this condition. We also discuss the clinical, neuropsychological, quality of life and economic impacts of epilepsy surgery.

Palliative Surgery for Drug-Resistant Epilepsy in Adult Patients. A Systematic Review of the Literature and a Pooled Analysis of Outcomes

BACKGROUND

Several types of palliative surgery to treat drug-resistant epilepsy (DRE) have been reported, but the evidence that is available is insufficient to help physicians redirect patients with DRE to the most appropriate kind of surgery.

METHODS

A systematic search in the PubMed and Scopus databases was performed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines to compare different clinical features, outcomes, and complications of adult patients submitted to callosotomy, vagal nerve stimulation, multiple subpial transections, deep brain stimulation, or responsive neurostimulation.

RESULTS

After 3447 articles were screened, 36 studies were selected, including the data of 1628 patients: 76 were treated with callosotomy, 659 were treated with vagal nerve stimulation, 416 were treated with deep brain stimulation, and 477 were treated with responsive neurostimulation. No studies including patients treated with multiple subpial transections met the inclusion criteria. The global weighted average seizure frequency reduction was 50.23%, and the global responder rate was 52.12%. There were significant differences among the palliative surgical procedures in term of clinical features of patients and epilepsy, seizure frequency reduction, and percentage of responders. Complications were differently distributed as well.

CONCLUSIONS

Our analysis highlights the necessity of prospective studies, possibly randomized controlled trials, to compare different forms of palliative epilepsy surgery. Moreover, by identifying the outcome predictors associated with each technique, the best responder may be profiled for each procedure.

Multimodal prognostic features of seizure freedom in epilepsy surgery

OBJECTIVE

Accurate preoperative predictions of seizure freedom following surgery for focal drug resistant epilepsy remain elusive. Our objective was to systematically evaluate all meta-analyses of epilepsy surgery with seizure freedom as the primary outcome, to identify clinical features that are consistently prognostic and should be included in the future models.

METHODS

We searched PubMed and Cochrane using free-text and Medical Subject Heading (MeSH) terms according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses. This study was registered on PROSPERO. We classified features as prognostic, non-prognostic and uncertain and into seven subcategories: 'clinical', 'imaging', 'neurophysiology', 'multimodal concordance', 'genetic', 'surgical technique' and 'pathology'. We propose a structural causal model based on these features.

RESULTS

We found 46 features from 38 meta-analyses over 22 years. The following were consistently prognostic across meta-analyses: febrile convulsions, hippocampal sclerosis, focal abnormal MRI, Single-Photon Emission Computed Tomography (SPECT) coregistered to MRI, focal ictal/interictal EEG, EEG-MRI concordance, temporal lobe resections, complete excision, histopathological lesions, tumours and focal cortical dysplasia type IIb. Severe learning disability was predictive of poor prognosis. Others, including sex and side of resection, were non-prognostic. There were limited meta-analyses investigating genetic contributions, structural connectivity or multimodal concordance and few adjusted for known confounders or performed corrections for multiple comparisons.

SIGNIFICANCE

Seizure-free outcomes have not improved over decades of epilepsy surgery and despite a multitude of models, none prognosticate accurately. Our list of multimodal population-invariant prognostic features and proposed structural causal model may serve as an objective foundation for statistical adjustments of plausible confounders for use in high-dimensional models.

PROSPERO REGISTRATION NUMBER

CRD42021185232.

Resection of bilateral occipital lobe lesions during a single operation as a treatment for bilateral occipital lobe epilepsy

BACKGROUND

Neurosurgical treatment of severe bilateral occipital lobe epilepsy usually involves two operations several mos apart.

AIM

To evaluate surgical resection of bilateral occipital lobe lesions during a single operation as a treatment for bilateral occipital lobe epilepsy.

METHODS

This retrospective case series included patients with drug-refractory bilateral occipital lobe epilepsy treated surgically between March 2006 and November 2015.

RESULTS

Preoperative evaluation included scalp video-electroencephalography (EEG), magnetic resonance imaging, and PET-CT. During surgery (bilateral occipital craniotomy), epileptic foci and important functional areas were identified by EEG (intracranial cortical electrodes) and cortical functional mapping, respectively. Patients were followed up for at least 5 years to evaluate treatment outcome (Engel grade) and visual function. The 20 patients (12 males) were aged 4-30 years (median age, 12 years). Time since onset was 3-20 years (median, 8 years), and episode frequency was 4-270/mo (median, 15/mo). Common manifestations were elementary visual hallucinations (65.0%), flashing lights (30.0%), blurred vision (20.0%) and visual field defects (20.0%). Most patients were free of disabling seizures (Engel grade I) postoperatively (18/20, 90.0%) and at 1 year (18/20, 90.0%), 3 years (17/20, 85.0%) and ≥ 5 years (17/20, 85.0%). No patients were classified Engel grade IV (no worthwhile improvement). After surgery, there was no change in visual function in 13/20 (65.0%), development of a new visual field defect in 3/20 (15.0%), and worsening of a preexisting defect in 4/20 (20.0%).

CONCLUSION

Resection of bilateral occipital lobe lesions during a single operation may be applicable in bilateral occipital lobe epilepsy.

Comparative Effectiveness of Stereotactic Electroencephalography Versus Subdural Grids in Epilepsy Surgery

OBJECTIVE

The aim was to compare the outcomes of subdural electrode (SDE) implantations versus stereotactic electroencephalography (SEEG), the 2 predominant methods of intracranial electroencephalography (iEEG) performed in difficult-to-localize drug-resistant focal epilepsy.

METHODS

The Surgical Therapies Commission of the International League Against Epilepsy created an international registry of iEEG patients implanted between 2005 and 2019 with ≥1 year of follow-up. We used propensity score matching to control exposure selection bias and generate comparable cohorts. Study endpoints were: (1) likelihood of resection after iEEG; (2) seizure freedom at last follow-up; and (3) complications (composite of postoperative infection, symptomatic intracranial hemorrhage, or permanent neurological deficit).

RESULTS

Ten study sites from 7 countries and 3 continents contributed 2,012 patients, including 1,468 (73%) eligible for analysis (526 SDE and 942 SEEG), of whom 988 (67%) underwent subsequent resection. Propensity score matching improved covariate balance between exposure groups for all analyses. Propensity-matched patients who underwent SDE had higher odds of subsequent resective surgery (odds ratio [OR] = 1.4, 95% confidence interval [CI] 1.05, 1.84) and higher odds of complications (OR = 2.24, 95% CI 1.34, 3.74; unadjusted: 9.6% after SDE vs 3.3% after SEEG). Odds of seizure freedom in propensity-matched resected patients were 1.66 times higher (95% CI 1.21, 2.26) for SEEG compared with SDE (unadjusted: 55% seizure free after SEEG-guided resections vs 41% after SDE).

INTERPRETATION

In comparison to SEEG, SDE evaluations are more likely to lead to brain surgery in patients with drug-resistant epilepsy but have more surgical complications and lower probability of seizure freedom. This comparative-effectiveness study provides the highest feasible evidence level to guide decisions on iEEG. ANN NEUROL 2021;90:927-939.

Determinants of seizure outcome after resective surgery following stereoelectroencephalography

OBJECTIVE

The aim of this study was to investigate seizure outcomes after resective epilepsy surgery following stereoelectroencephalography (SEEG), including group characteristics, comparing surgical and nonsurgical groups and assess predictors of time to seizure recurrence.

METHODS

Clinical and EEG data of 536 consecutive patients who underwent SEEG at Cleveland Clinic Epilepsy Center between 2009 and 2017 were reviewed. The primary outcome was defined as complete seizure freedom since the resective surgery, discounting any auras or seizures that occurred within the 1st postoperative week. In addition, the rate of seizure freedom based on Engel classification was determined in patients with follow-up of ≥ 1 year. Presumably significant outcome variables were first identified using univariate analysis, and Cox proportional hazards modeling was used to identify outcome predictors.

RESULTS

Of 527 patients satisfying study criteria, 341 underwent resective surgery. Complete and continuous seizure freedom after surgery was achieved in 55.5% of patients at 1 year postoperatively, 44% of patients at 3 years, and 39% of patients at 5 years. As a secondary outcome point, 58% of patients achieved Engel class I seizure outcome for at least 1 year at last follow-up. Among surgical outcome predictors, in multivariate model analysis, the seizure recurrence rate by type of resection (p = 0.039) remained statistically significant, with the lowest risk of recurrence occurring after frontal and temporal lobe resections compared with multilobar and posterior quadrant surgeries. Patients with a history of previous resection (p = 0.006) and bilateral implantations (p = 0.023) were more likely to have seizure recurrence. The absence of an MRI abnormality prior to resective surgery did not significantly affect seizure outcome in this cohort.

CONCLUSIONS

This large, single-center series shows that resective surgery leads to continuous seizure freedom in a group of patients with complex and severe pharmacoresistant epilepsy after SEEG evaluation. In addition, up to 58% of patients achieved seizure freedom at last follow-up. The authors' results suggest that SEEG is equally effective in patients with frontal and temporal lobe epilepsy with or without MRI identified lesions.

Brain-responsive corticothalamic stimulation in the pulvinar nucleus for the treatment of regional neocortical epilepsy: A case series

Drug‐resistant focal epilepsy with regional neocortical seizure onsets originating from the posterior quadrant can be particularly difficult to treat with resective surgery due to the overlap with eloquent cortex. Published reports indicate that corticothalamic treatment targeting the anterior or centromedian nucleus of the thalamus with direct brain‐responsive stimulation may be an effective approach to treat regional neocortical epilepsy. The pulvinar has remained largely unstudied as a neurostimulation target to treat refractory epilepsy. Because the pulvinar has connections with the posterior quadrant, neurostimulation may be effective if applied to seizures originating in this area. We performed a retrospective chart review of patients with regional neocortical seizure onsets in the posterior quadrant treated with the RNS System. Demographics, epilepsy history, clinical seizure frequencies, and neuropsychological testing results were obtained from the chart. Electrocorticogram (ECoG) records stored by the RNS System were reviewed to evaluate electrographic seizure onset patterns. Our patients were followed for 10, 12.5, and 15 months. All patients were responders (≥50% seizure reduction), and two of the three patients experienced a ≥90% reduction in seizures at the last follow‐up. Pre‐ and postsurgical neuropsychological evaluations were compared for two of the patients, and there was no evidence of cognitive decline found in either patient. Interestingly, mild cognitive improvements were reported. The third patient had only postimplant neuropsychological testing data available. Findings for this patient suggested executive dysfunction that was present prior to the RNS System which did not worsen with surgery. A visual inspection of ECoGs revealed near‐simultaneous seizure onsets in neocortical and pulvinar leads in two patients. Seizure onsets in the third patient were more variable. This is the first published report of brain‐responsive neurostimulation targeting the pulvinar to treat refractory regional onset epilepsy of posterior quadrant origin.

Adult occipital lobe epilepsy: 12-years on

OBJECTIVE

Occipital lobe epilepsies (OLE) comprise 5-10% of focal epilepsies in surgical and paediatric series; with little data from adult medical cohorts. This longitudinal study examined OLE patients, to characterise prevalence, semiology, co-morbidity and prognosis in a neurology outpatient setting.

METHODS

24 adult OLE patients identified over 12 months from 1548 patients in a neurologist's service were followed over 12 years.

RESULTS

92% of these OLE patients had simple visual hallucinations, misdiagnosed in 40% of cases. 75% had co-morbid interictal migraine and 38% had visual field defects. Only 33% achieved long-term remission, and only 2 /10 (20%) of OLE patients with a structural aetiology were seizure-free. The two patients with migralepsy achieved remission.

CONCLUSION

Adult OLE accounted for 7.7% of focal epilepsies in this cohort, misdiagnosed or misclassified in 40%. Most patients had co-existing migraine. A minority had migralepsy characterised by a longer aura and good prognosis. Remission rates were lower than that of childhood OLE and general adult epilepsy populations, strengthening the argument for considering epilepsy surgery in drug-resistant OLE patients with a structural cause. Precision medicine will potentially refine diagnosis and management in those OLE patients without an identified cause but is predicated on accurate clinical phenotyping.

Changes in Functional Connectivity of Specific Cerebral Regions in Patients with Toothache: A Resting-State Functional Magnetic Resonance Imaging Study

Objective

In order to further study the changes of cerebral functional connectivity in patients with toothache (TA), this study used the resting-state functional magnetic resonance imaging (rs-fMRI) technique and degree centrality (DC) analysis method.

Methods

Eighteen TA patients (8 males, 10 females) and 18 healthy individuals of similar age, sex, and educational levels were recruited as healthy controls (HCs) to take part in the study, and all underwent rs-fMRI examination. And DC technology was used to compare the state of their cerebral spontaneous functional activity. In order to compare the average DC values of the TA group and HC group, we used independent two-sample t-test and receiver operating characteristic (ROC) curve to compare the difference of DC values between the two groups, so as to distinguish the accuracy of TA diagnosis. Finally, we also carry out Pearson's linear regression analysis.

Results

The TA group showed higher DC values in the right lingual gyrus (RLG), right precentral gyrus, and left middle temporal gyrus (LMTG) than HCs. Moreover, ROC curve analysis indicated that the area under the curve (AUC) of each cerebral region studied had high accuracy. In addition, linear analysis indicated that the DC values of the RLG were positively correlated with the Hospital Anxiety and Depression Scale (HADS) (r = 0.844, p < 0.001), and the DC values of the LMTG were positively correlated with the visual analogue scale (VAS) (r = 0.723, p < 0.001).

Conclusion

TA generates abnormal changes in the intrinsic activity patterns of pain-related and vision-related areas of the cerebral cortex, which will be beneficial to reveal the underlying neuropathic mechanisms.

Evolution of patients with surgically treated drug-resistant occipital lobe epilepsy

Background

This study was to describe the evolution of patients who underwent surgical treatment of drug- resistant occipital lobe epilepsy (OLE) at our institution.

Methods

We performed a retrospective analysis of data collected from electronic and paper clinical records of 20 patients who were diagnosed of OLE and underwent epilepsy surgery at our institution between 1998 and 2018. We also contacted patients by telephone and asked them to fill out a questionnaire about quality of life in epilepsy (QOLIE-10). Assembled data were analyzed using descriptive statistics.

Results

The age at surgery ranged between 19 and 55 years. The period encompassing epilepsy onset and the date of surgery was variable. Semiology of seizures included visual symptoms in 75% of patients. In 90% of cases subdural grids, depth electrodes or a combination of both were used to plan the surgery. The most frequent neuroimaging and histopathological finding was cortical dysplasia (55%). The postoperative follow-up period was up to 15 years. The most common score on the Engel scale was I (70%). Visual deficits increased after surgery. Median score on QOLIE-10 questionnaire was 82.5 (interquartile range: 32.5).

Conclusion

Surgical treatment of drug-resistant OLE offers hopeful results to those patients who have run out of pharmacological options and leads to postoperative deficits that are deemed expectable and occasionally acceptable.

Seizures following surgery for supratentorial extratemporal low-grade tumors in children: a multicenter retrospective study

OBJECTIVE

Resection of brain tumors may lead to new-onset seizures but may also reduce seizure rates in patients presenting with seizures. Seizures are seen at presentation in about 24% of patients with brain tumors. For lesional epilepsy in general, early resection is associated with improved seizure control. However, the literature is limited regarding the occurrence of new-onset postoperative seizures, or rates of seizure control in those presenting with seizures, following resections of extratemporal low-grade gliomas (LGGs) in children.

METHODS

Data were collected retrospectively from 4 large tertiary centers for children (< 18 years of age) who underwent resection of a supratentorial extratemporal (STET) LGG. The patients were divided into 4 groups based on preoperative seizure history: no seizures, up to 2 seizures, more than 2 seizures, and uncontrolled or refractory epilepsy. The authors analyzed the postoperative occurrence of seizures and the need for antiepileptic drugs (AEDs) over time for the various subgroups.

RESULTS

The study included 98 children. Thirty patients had no preoperative seizures, 18 had up to 2, 16 had more than 2, and 34 had refractory or uncontrolled epilepsy. The risk for future seizures was higher if the patient had seizures within 1 month of surgery. The risk for new-onset seizures among patients with no seizures prior to surgery was low. The rate of seizures decreased over time for children with uncontrolled or refractory seizures. The need for AEDs was higher in the more active preoperative seizure groups; however, it decreased with time.

CONCLUSIONS

The resection of STET LGGs in children is associated with a low rate of postoperative new-onset epilepsy. For children with preoperative seizures, even with uncontrolled epilepsy, most have a significant improvement in the seizure activity, and many may be weaned off their AEDs.

Tailored multilobar disconnective epilepsy surgery in the posterior quadrant

OBJECTIVE

Surgical treatment of drug-resistant epilepsy originating from the posterior quadrant (PQ) of the brain often requires large multilobar resections, and disconnective techniques have been advocated to limit the risks associated with extensive tissue removal. Few previous studies have described a tailored temporoparietooccipital (TPO) disconnective approach; only small series with short postoperative follow-ups have been reported. The aim of the present study was to present a tailored approach to multilobar PQ disconnections (MPQDs) for epilepsy and to provide details about selection of patients, presurgical investigations, surgical technique, treatment safety profile, and seizure and cognitive outcome in a large, single-center series of patients with a long-term follow-up.

METHODS

In this retrospective longitudinal study, the authors searched their prospectively collected database for patients who underwent MPQD for drug-resistant epilepsy in the period of 2005-2017. Tailored MPQDs were a posteriori grouped as follows: type I (classic full TPO disconnection), type II (partial TPO disconnection), type III (full temporooccipital [TO] disconnection), and type IV (partial TO disconnection), according to the disconnection plane in the occipitoparietal area. A bivariate statistical analysis was carried out to identify possible predictors of seizure outcome (Engel class I vs classes II-IV) among several presurgical, surgical, and postsurgical variables. Preoperative and postoperative cognitive profiles were also collected and evaluated.

RESULTS

Forty-two consecutive patients (29 males, 24 children) met the inclusion criteria. According to the presurgical evaluation (including stereo-electroencephalography in 13 cases), 12 (28.6%), 24 (57.1%), 2 (4.8%), and 4 (9.5%) patients received a type I, II, III, or IV MPQD, respectively. After a mean follow-up of 80.6 months, 76.2% patients were in Engel class I at last contact; at 6 months and 2 and 5 years postoperatively, Engel class I was recorded in 80.9%, 74.5%, and 73.5% of cases, respectively. Factors significantly associated with seizure freedom were the occipital pattern of seizure semiology and the absence of bilateral interictal epileptiform abnormalities at the EEG (p = 0.02). Severe complications occurred in 4.8% of the patients. The available neuropsychological data revealed postsurgical improvement in verbal domains, whereas nonunivocal outcomes were recorded in the other functions.

CONCLUSIONS

The presented data indicate that the use of careful anatomo-electro-clinical criteria in the presurgical evaluation allows for customizing the extent of surgical disconnections in PQ epilepsies, with excellent results on seizures and an acceptable safety profile.

Neurosurgical approaches to pediatric epilepsy: Indications, techniques, and outcomes of common surgical procedures

Epilepsy is a common pediatric neurological condition, and approximately one-third of children with epilepsy are refractory to medical management. For these children neurosurgery may be indicated, but operative success is dependent on complete delineation of the epileptogenic zone. In this review, surgical techniques for pediatric epilepsy are considered. First, potentially-curative operations are discussed and broadly divided into resections and disconnections. Then, two palliative approaches to seizure control are reviewed. Finally, future neurosurgical approaches to epilepsy are considered.

Getting the best outcomes from epilepsy surgery

Neurosurgery is an underutilized treatment that can potentially cure drug‐refractory epilepsy. Careful, multidisciplinary presurgical evaluation is vital for selecting patients and to ensure optimal outcomes. Advances in neuroimaging have improved diagnosis and guided surgical intervention. Invasive electroencephalography allows the evaluation of complex patients who would otherwise not be candidates for neurosurgery. We review the current state of the assessment and selection of patients and consider established and novel surgical procedures and associated outcome data. We aim to dispel myths that may inhibit physicians from referring and patients from considering neurosurgical intervention for drug‐refractory focal epilepsies. Ann Neurol 2018;83:676–690

Prognostic value of ictal onset patterns in postsurgical outcome of temporal lobe epilepsy

Background: To investigate ictal onset patterns (IOP) in scalp electroencephalography (EEG) of patients with temporal lobe epilepsy (TLE) and their prognostic effect on the postoperative outcome. Methods: We conducted a retrospective cohort study between 2011 and 2015 in our referral Epilepsy Surgery Center enrolling adult patients with refractory TLE and a visible epileptogenic lesion in magnetic resonance imaging (MRI), who underwent epilepsy surgery. Demographic, clinical and MRI findings were collected and ictal findings during video-EEG monitoring were reviewed in detail. The correlation between preoperative findings and the postsurgical outcome was analyzed. Results: We reviewed 303 seizures in 93 patients. Rhythmic theta and rhythmic spike/sharp and wave were respectively the most common initial ictal pattern and late significant discharges. Engel class I outcome was observed in 88.2% of patients. Female sex, aura, the absence of secondary generalization, rhythmic theta as initial ictal pattern and concordance of ictal-interictal EEG findings were correlated with favorable 1-year postsurgical outcome. Conclusion: Preoperative clinical and EEG findings can provide valuable information regarding postsurgical prognosis in TLE patients.