Long-term Outcome of Seizure Control and Neurologic Performance After Limited Hippocampal Radiofrequency Thermocoagulation for Mesial Temporal Lobe Epilepsy

OBJECTIVE

Limited hippocampal radiofrequency thermocoagulation (RFTC) for patients with mesial temporal lobe epilepsy was associated with good short-term seizure control and few complications. We aimed to demonstrate the neuropsychologic outcomes and assess the prognostic factors of long-term seizure control in these patients.

METHODS

We included all patients with mesial temporal lobe epilepsy who underwent limited hippocampal RFTC from January 2016 to December 2020. Clinical data of age, sex, seizure control before and after operation were all corrected. Pre- and postoperative neuropsychologic function including full-scale intelligence quotient (FSIQ), memory quotient, and the Mini-Mental State Examination was used.

RESULTS

Thirty-one patients (17 female and 14 male) with a mean epilepsy duration of 22.3 years and seizure frequency of 5.7 times per month were included. The intraoperative seizure rate was 19.3%, and a higher preoperative seizure frequency (P = 0.001) and longer duration of epilepsy (P = 0.042) were associated with the occurrence of intraoperative seizures. The postoperative FSIQ scores were significantly better than preoperative scores (mean 92.1 vs. 89.7, P = 0.014). Nine patients (29%) who underwent limited hippocampal RFTC were seizure-free at 1 year of follow-up. Responders represented 58% (n = 18) of patients at 1 year. The mean follow-up period was 34.7 ± 13.3 months. Five patients remained seizure free and 13 patients are still responders at the last follow-up visits. Long-term seizure frequency was 2.32 ± 2.86 times per month.

CONCLUSIONS

Limited hippocampal RFTC is a safe stereotactic minimal invasive procedure with good neuropsychologic outcome and acceptable efficacy of seizure reduction in appropriately selected patients.

Feasibility of Tailored Unilateral Disconnection vs Callosotomy for Refractory Epilepsy in Patients with Bilateral Parieto-Occipital Gliosis Following Perinatal Insult

BACKGROUND

Patients with perinatal hypoxia (PH) and drug-refractory epilepsy (DRE) often have bilateral parieto-occipital gliosis. Surgical management of such patients is a dilemma.

OBJECTIVE

To identify preoperative determinants for unilateral disconnection vs callosotomy, and analyze the surgical outcome in such patients.

METHODS AND MATERIAL

This was a retrospective analysis of patients with DRE and history of PH, with MRI abnormalities restricted to bilateral posterior quadrants. Preoperative semiology, epilepsy duration and seizure frequency were recorded. Based on the concordance between the results of non-invasive tests, patients underwent either posterior quadrant disconnection (PQD) or corpus callosotomy (CC). Preoperative variables were analyzed and corelated to the postoperative seizure freedom.

RESULTS

Fourteen patients were identified, 6 underwent PQD and 8 underwent CC. At follow up of 39.17 ± 23.75 months, 66.66% of patients (4/6) in the PQD subgroup had an ILAE Class I outcome. While none in the CC group attained seizure freedom, 87.5% (7/8) had more than 50% reduction in seizure frequency (follow up: 42 ± 27.31 months). Patients with a poor outcome had significantly greater seizure frequency (P = 0.05) and history of drop attacks (P = 0.04) in both the groups. Magnetoencephalography (MEG) accurately localized the epileptogenic zone in all of the patients with good outcome (P = 0.015). Concordance with single photon emission tomography (SPECT) was also a predictor of favorable outcome (P = 0.041).

CONCLUSIONS

A history of drop attacks with high seizure frequency is associated with poor postoperative seizure outcome. Unilateral PQD is feasible and leads to superior seizure-free outcomes, even in cases with widespread and bilateral imaging and electrical abnormalities, provided the other preoperative investigations are concordant in localizing the epileptogenic zone.

Mini Temporal Craniotomy Using Anatomical Surface Landmarks for Temporal Lobe Epilepsy: Technical Note and Clinical Outcomes

BACKGROUND

Patients with temporal lobe epilepsy are subjected to standard temporal lobectomy wherever indicated. This is performed using a reverse question mark flap and a standard frontotemporal craniotomy. We describe the technique of minitemporal craniotomy (3 × 3cms) for temporal lobe epilepsy (TLE) and analyze the clinical outcomes of patients operated using this approach.

OBJECTIVES

To describe the technique of minitemporal craniotomy for TLE without navigation guidance and to analyze the clinical outcomes of patients operated using this approach.

MATERIALS AND METHOD

This was a retrospective analysis of all consecutive TLE cases operated at our institute from 2014 to 2019, via minitemporal craniotomy, using surface landmarks only without navigation guidance. The surgical technique, indications for surgery, and their clinical outcomes were analyzed.

RESULTS

A total number of 48 patients underwent surgery for TLE. There were no complications except three patients who had transient hemiparesis. The average duration of hospital stay was 4 days following surgery. Out of 28 patients with mesial temporal sclerosis, 22 (82%) had international league against epilepsy, Class I seizure outcome, 4 (12.5%) had Class II outcome and 2 (5.5%) had Class III outcome. 9 patients with dysembryoplastic neurectodermal tumor (DNET), 4 gangliogliomas, 2 neurocystecercosis (NCC), all had Class I outcome. Out of the five patients with MTS and associated anterior temporal focal cortical dysplasia (FCD), four (80%) had a Class I outcome, whereas one (20%) had Class II outcome.

CONCLUSION

Utilizing surface anatomical landmarks, minitemporal craniotomy can be performed in even peripheral centers without neuronavigation, with good cosmesis, seizure outcomes.

Clinical spectrum of pediatric drug refractory epilepsy secondary to parieto-occipital gliosis

BACKGROUND

Parieto-occipital (PO) gliosis secondary to perinatal insult, is often associated with neurologic sequelae such as epilepsy, which can be drug resistant.

OBJECTIVE

To evaluate the spectrum of epilepsy among patients presenting with seizures in association with PO gliosis and to determine factors that influence the development of epileptic encephalopathy (EE) in these patients.

METHODS

We retrospectively evaluated patients aged < 16 years with drug refractory epilepsy and PO gliosis who underwent video electroencephalography (Video EEG). We evaluated the clinical, electrophysiological and radiological profile including treatment responsiveness of subjects with EE.

RESULTS

One hundred one patients (M: F=3:1) with mean age of onset of epilepsy at 28.9 ± 33.1 months were recruited into the study. Based on video EEG findings, Based on video EEG findings, the commonest type of focal onset ictus was tonic seizures with impaired awareness (n = 26, 29.9%). Myoclonic jerks (n = 20, 23%) were the commonest type of generalised onset seizures. Ictal onset from parieto occipital region were observed in 28 patients. Ictal onset from frontal, temporal and fronto temporal region were observed in 6 (6.8%), 7(7.9%) and 9 (8.9%) patients, respectively. Comparison of the seizure types and ictal onset among subgroups of patients with occipital gliosis, parieto-occipital gliosis and parieto-occipital with frontal gliosis revealed that the extent of gliosis did not significantly affect seizure semiology or ictal onset. EE was significantly associated with presence of neonatal seizures (p = 0.04), hypoglycaemia (p = 0.005), longer duration of ICU stay (Z score = -3.55, p < 0.001) and younger age of onset of seizures (Z score = - 2.97, p = 0.03). Eleven out of eighteen (64.7%) subjects with EE showed greater than 50% improvement in seizure frequency following three months of pulse intravenous methylprednisolone therapy.

CONCLUSIONS

Among subjects with PO gliosis on MRI, the seizure semiology is unaffected by laterality, radiologic extension beyond the occipital cortex or presence of ulegyria. Patients with PO gliosis can have florid interictal epileptiform discharges anteriorly and can have seizures with ictal onset from frontal and temporal region. Development of EE is strongly related to the age of onset of seizures, neonatal seizures, prolonged NICU admission, rather than the radiological findings. Subjects with EE and PO gliosis show good response to intravenous pulse methylprednisolone.

Vagal Nerve Stimulation in the Management of Epilepsy - Recent Concepts

Epilepsy surgery currently offers the best treatment for patients with drug-refractory epilepsy (DRE). Resective surgery, in the presence of a well-localized epileptogenic focus, remains the best modality towards achieving seizure freedom. However, localization of the focus may not be possible in all the cases of DRE, despite comprehensive epilepsy workup. Neuromodulation techniques such as vagal nerve stimulation (VNS), deep brain stimulation (DBS) and responsive neurostimulation (RNS) may be a good alternative in these cases. This article intends to provide an overview of VNS in the management of DRE, including indications, comprehensive preoperative workup, exemplified by case illustrations and outcomes by reviewing the evidence available in the literature.

Epilepsy surgery in COVID times-a unique conundrum

The COVID-19 pandemic has forced hospitals to prioritize admissions. Epilepsy surgeries have been postponed at most centers. As the pandemic continues with no definite end in sight in the near future, the question arises until when such patients should be denied appropriate treatment. A 12-year-old child with left-sided Rasmussen's encephalitis with drug refractory epilepsy (DRE) presented at the height of the pandemic, with worsening of seizure frequency from 4-5/day to 20/day, with new-onset epilepsia partialis continua. She demonstrated features of progressive cognitive decline. The pros and cons of operating during the pandemic were discussed with the parents by a multidisciplinary team. She underwent endoscopic left hemispherotomy. Postoperatively she became seizure free but developed hospital-acquired mild COVID infection for which she was treated accordingly. Chosen cases of severe DRE, as the one illustrated above, who are deemed to benefit from surgery by a multidisciplinary team of physicians, should be re-categorized into the most severe class of patients and scheduled for surgery as soon as possible. The risk benefit ratio of the seizures being mitigated by surgery on one hand and possibility of acquiring COVID infection during hospital stay has to be balanced and a decision made accordingly.

Quality of Life and Its Determinants in Adult Drug Refractory Epilepsy Patients Who Were Not Candidates for Epilepsy Surgery: A Correlational Study

Background and Purpose

This study was performed to elucidate quality of life (QOL) and its determinants in adult drug refractory epilepsy (DRE) patients who were not candidates for epilepsy surgery.

Methods

A correlational study was performed at the center of excellence, epilepsy between July 2014 to June 2016. All consecutive DRE patients who were not candidates for epilepsy surgery were enrolled. The outcomes were QOL, assessed using the quality of life inventory in epilepsy-31 items (QOLIE-31) inventory and the correlation of QOL with epilepsy-related variables like seizure severity and frequency. We also compared current QOL with QOL during the pre-surgical evaluation to strengthen our study outcome.

Results

A total of 129 adult patients were enrolled over two years. The mean age was 26.5 ± 6.7 years and male: female ratio was 3: 1. The mean age at epilepsy onset was 9.6 ± 6.6 years and mean duration of epilepsy was 14.9 ± 7.5 years. There was lower seizure frequency than during pre-surgical evaluation in 37.2% of patients, while in 62.8% the seizure frequency remained the same or was higher. Nine (6.98%) patients became seizure free. In comparison to QOL status during the pre-surgical evaluation, there was statistically significant worsening of QOL in all domains (p < 0.01). Seizure severity significantly correlated with almost all QOL domains (p ≤ 0.01), while seizure frequency significantly correlated with only the single domain of overall QOL (p = 0.03).

Conclusions

The QOL of DRE patients who were not candidates for epilepsy surgery worsened relative to the QOL during the pre-surgical evaluation period. Seizure severity significantly correlated with QOL, but seizure frequency did not.

[Invasive stimulation procedures and EEG diagnostics in epilepsy]

Stimulation has been performed experimentally and in small case series to treat epilepsy since the 1970s. Since the introduction of vagus nerve stimulation in 1997 and intracranial stimulation methods in 2011 into patient care, invasive stimulation has become a rapidly developing but infrequently used therapeutic option in Europe. Whereas vagus nerve stimulation is frequently used, particularly in the USA, intracranial stimulation differs in its regional availability. In order to improve the efficacy of stimulation, develop criteria for its use and assure low complication rates, a concentration on experienced centers and multicenter data acquisition and sharing are needed.Invasive electroencephalographic (EEG) monitoring with subdural electrodes and especially with stereotactically implanted depth electrodes have been used increasingly more often for presurgical evaluation in recent years. They are applied when non-invasive diagnostics show insufficient results to exactly identify the location and extent of the epileptogenic zone or cannot be adequately distinguished from eloquent cortex areas. Complications include intracranial hemorrhage, infections and increased intracranial pressure but lasting deficits or even death are rare (≤2 %). The outcome of invasive monitoring is inferior to non-invasive monitoring because of the higher degree of complexity of the cases; however, it is far superior to the seizure-free rates achieved by anticonvulsant drug treatment alone.

A screening tool to identify surgical candidates with drug refractory epilepsy in a resource limited settings

OBJECTIVES

Access to epilepsy surgery remains a considerable challenge in contemporary healthcare systems. Given the limitations in resources and demand for Epilepsy Monitoring Unit (EMU) assessments, information that can be used to expedite the process is of great value. The purpose of this study was to identify variables prior to EMU admission that may be associated with candidacy for prospective epilepsy surgery.

METHODS

This was a prospective study conducted at the Department of Neurology, All India Institute of Medical Sciences, New Delhi, India. We identified two subgroups of patients from 501 drug refractory epilepsy (DRE) patients admitted in EMU of Neurology Department, AIIMS from 2006 onwards following validation of proposed tool in 40 patients. They on subsequent investigations were either cleared or not cleared for epilepsy surgery. A tool consisting of variables likely to predict surgical candidacy in persons with DRE in Indian settings was developed for identification of patients who might benefit from an early epilepsy surgery evaluation.

RESULTS

Statistical analysis revealed significant differences between the two groups for several variables. Non-surgical candidates had non-disabling seizures, seizures improved with a combination of drugs, had little/no AEDs side effects and had near normal or normal scalp EEG and MRI brain.

SIGNIFICANCE

Using the best available evidence, we developed a decision making tool which can provide a comprehensive quick guide for determining candidacy for epilepsy surgery evaluations in resource limited settings. Given the demand for EMU assessments, information that can be used to expedite the process is of value.

Effect of reduction of antiepileptic drugs in patients with drug-refractory epilepsy

PURPOSE

The present study was conducted with the aim of evaluating the effects of reducing the number of antiepileptic drugs (AEDs) administered to patients with drug-refractory epilepsy (DRE) during their admission and document any change in seizure frequency in subsequent follow up.

METHODS

A total of 962 patients with DRE who were admitted to the neurology wards waiting for connection to video EEG were recruited for this prospective study. After their admission to the neurology ward, modifications in the number and dosage of AEDs were done with a target of a maximum of three AEDs in every patient. Drug tapering was done using a standardized protocol. The primary outcome was the change in seizure frequency in the follow-up period of 6 months. Secondary outcome measures were the adverse event profile (AEP) and the quality of life (QOL).

RESULTS

Of the 1134 patients screened, 962 patients gave consent to participate in the study. The mean number of AEDs received by each patient was 4.24. After the tapering following a standardized protocol each patient received a mean of 2.65 AEDs per patient. In 82.70% patients with DRE, there was either a reduction or no change in seizure frequency in the subsequent 6 months follow up. There was a significant reduction in the AEP score after the reduction in the number of AEDs (P = 0. 001).

CONCLUSION

Our study proves that optimization of reduction of the number of AED's in patients with DRE leads to reduction or no change in seizure frequency with a significant decrease in adverse effects.