The anterior sylvian point as a reliable landmark for the anterior temporal lobectomy in mesial temporal lobe epilepsy: technical note, case series, and cadaveric dissection.

Introduction: Mesial temporal lobe epilepsy (MTLE) is one of the most prevalent forms of focal epilepsy in surgical series, particularly among adults. Over the decades, different surgical strategies have been developed to address drug-resistant epilepsy while safeguarding neurological and cognitive functions. Among these strategies, anterior temporal lobectomy (ATL), involving the removal of the temporal pole and mesial temporal structures, has emerged as a widely employed technique. Numerous modifications have been proposed to mitigate the risks associated with aphasia, cognitive issues, and visual field defects. Methods: Our approach is elucidated through intraoperative and cadaveric dissections, complemented by neuroradiological and cadaveric measurements of key anatomical landmarks. A retrospective analysis of patients with drug-resistant MTLE who were treated using our ATL technique at IRCCS Neuromed (Pozzilli) is presented. Results: A total of 385 patients were treated with our ATL subpial technique anatomically focused on the anterior Sylvian point (ASyP). The mean FU was 9.9 ± 5.4 years (range 1-24). In total, 84%of patients were free of seizures during the last follow-up, with no permanent neurological deficits. Transient defects were as follows: aphasia in 3% of patients, visual field defects in 2% of patients, hemiparesis in 2% of patients, and cognitive/memory impairments in 0.8% of patients. In cadaveric dissections, the ASyP was found at a mean distance from the temporal pole of 3.4 ± 0.2 cm (range 3-3.8) at the right side and 3.5 ± 0.2 cm (3.2-3.9) at the left side. In neuroimaging, the ASyP resulted anterior to the temporal horn tip in all cases at a mean distance of 3.2 ± 0.3 mm (range 2.7-3.6) at the right side and 3.5 ± 0.4 mm (range 2.8-3.8) at the left side. Discussion: To the best of our knowledge, this study first introduces the ASyP as a reliable and reproducible cortical landmark to perform the ATL to overcome the patients' variabilities, the risk of Meyer's loop injury, and the bias of intraoperative measurements. Our findings demonstrate that ASyP can be a safe cortical landmark that is useful in MTLE surgery because it is constantly present and is anterior to risky temporal regions such as temporal horn and language networks.

Chronologic Changes in Transcranial Motor Evoked Potential During Anterior Temporal Lobectomy in Patients with Temporal Lobe Epilepsy: A Single-Center Cross-Sectional Analytic Study.

OBJECTIVE: Despite the benefits of anterior temporal lobectomy with amygdalohippocampectomy in patients with temporal lobe epilepsy (TLE), approximately up to 5% may have hemiparesis as its postoperative complication. This paper aims to describe which step/s of the anterior temporal lobectomy with amygdalohippocampectomy have the highest probability of having the greatest decrease in motor evoked potential (MEP) amplitude. METHODS: This study used a cross-sectional design of obtaining data from TLE patients who underwent anterior temporal lobectomy with amygdalohippocampectomy with transcranial MEP monitoring. Each of the following steps were evaluated for reduction in MEP amplitude: 1) dural opening, 2) opening the inferior horn, 2) vertical temporal lobe resection 3) subpial dissection, 4) temporal lobe stem resection, 5) lateral temporal lobe resection, 6) hippocampal resection, 7) amygdala resection, 8) uncus resection, and 9) dural closure. RESULTS: Nineteen patients were included in the study. Based on the Friedman Test, 1 or more steps had significantly different average MEP amplitude reductions (Friedman = 50.7, P = 0.0001). When compared with baseline (100%, cutoff P = 0.005), hippocampal resection (z = -3.81, P < 0.0001), T1 subpial dissection (z = -3.2, P = 0.0010), uncus resection (z = -3.48, P = 0.0002), temporal stem resection (z = -3.26, P = 0.001), lateral temporal lobe resection (z = -3.13, P = 0.002), and amygdalectomy (-z = -3.37, P = 0.0005) were significantly lower. Of these, hippocampal resection, uncus resection, and amygdalectomy were deemed highly significant. CONCLUSIONS: MEP amplitude tends to decrease during amygdala, hippocampal, and uncal resection because of surgical manipulation of anterior choroidal arteries, which can potentially cause hemiparesis. Careful attention should be paid to changes in MEP during these steps.

Accounting for repeat intervention costs in the economic comparison of laser interstitial thermal therapy and anterior temporal lobectomy for treatment of refractory temporal lobe epilepsy.

OBJECTIVE: Laser interstitial thermal therapy (LITT) is an alternative to anterior temporal lobectomy (ATL) for the treatment of temporal lobe epilepsy that has been found by some to have a lower procedure cost but is generally regarded as less effective and sometimes results in a subsequent procedure. The goal of this study is to incorporate subsequent procedures into the cost and outcome comparison between ATL and LITT. METHODS: This single-center, retrospective cohort study includes 85 patients undergoing ATL or LITT for temporal lobe epilepsy during the period September 2015 to December 2022. Of the 40 patients undergoing LITT, 35 % (N = 14) underwent a subsequent ATL. An economic cost model is derived, and difference in means tests are used to compare the costs, outcomes, and other hospitalization measures. RESULTS: Our model predicts that whenever the percentage of LITT patients undergoing subsequent ATL (35% in our sample) exceeds the percentage by which the LITT procedure alone is less costly than ATL (7.2% using total patient charges), LITT will have higher average patient cost than ATL, and this is indeed the case in our sample. After accounting for subsequent surgeries, the average patient charge in the LITT sample ($103,700) was significantly higher than for the ATL sample ($88,548). A second statistical comparison derived from our model adjusts for the difference in effectiveness by calculating the cost per seizure-free patient outcome, which is $108,226 for ATL, $304,052 for LITT only, and $196,484 for LITT after accounting for the subsequent ATL surgeries. SIGNIFICANCE: After accounting for the costs of subsequent procedures, we found in our cohort that LITT is not only less effective but also results in higher average costs per patient than ATL as a first course of treatment. While cost and effectiveness rates will vary across centers, we also provide a model for calculating cost effectiveness based on individual center data.

Surgical outcomes in children with drug-resistant epilepsy and hippocampal sclerosis.

BACKGROUND: Hippocampal sclerosis (HS) is a common surgical substrate in adult epilepsy surgery cohorts but variably reported in various pediatric cohorts. OBJECTIVE: We aimed to study the epilepsy phenotype, radiological and pathological variability, seizure and neurocognitive outcomes in children with drug-resistant epilepsy and hippocampal sclerosis (HS) with or without additional subtle signal changes in anterior temporal lobe who underwent surgery. METHODS: This retrospective study enrolled children with drug-resistant focal epilepsy and hippocampal sclerosis with or without additional subtle T2-Fluid Attenuated Inversion Recovery (FLAR)/Proton Density (PD) signal changes in anterior temporal lobe who underwent anterior temporal lobectomy with amygdalohippocampectomy. Their clinical, EEG, neuropsychological, radiological and pathological data were reviewed and summarized. RESULTS: Thirty-six eligible patients were identified. The mean age at seizure onset was 3.7 years; 25% had daily seizures at time of surgery. Isolated HS was noted in 22 (61.1%) cases and additional subtle signal changes in ipsilateral temporal lobe in 14 (38.9%) cases. Compared to the normative population, the group mean performance in intellectual functioning and most auditory and visual memory tasks were significantly lower than the normative sample. The mean age at surgery was 12.3 years; 22 patients (61.1%) had left hemispheric surgeries. ILAE class 1 outcomes was seen in 28 (77.8%) patients after a mean follow up duration of 2.3 years. Hippocampal sclerosis was noted pathologically in 32 (88.9%) cases; type 2 (54.5%) was predominant subtype where further classification was possible. Additional pathological abnormalities were seen in 11 cases (30.6%); these had had similar rates of seizure freedom as compared to children with isolated hippocampal sclerosis/gliosis (63.6% vs 84%, p=0.21). Significant reliable changes were observed across auditory and visual memory tasks at an individual level post surgery. CONCLUSIONS: Favourable seizure outcomes were seen in most children with isolated radiological hippocampal sclerosis. Patients with additional pathological abnormalities had similar rates of seizure freedom as compared to children with isolated hippocampal sclerosis/gliosis.

Comparison of minimally invasive to standard temporal lobectomy approaches to epilepsy surgery: Seizure relief and visual confrontation naming outcomes.

The purpose of this study was to systematically examine three different surgical approaches in treating left medial temporal lobe epilepsy (mTLE) (viz., subtemporal selective amygdalohippocampectomy [subSAH], stereotactic laser amygdalohippocampotomy [SLAH], and anterior temporal lobectomy [ATL]), to determine which procedures are most favorable in terms of visual confrontation naming and seizure relief outcome. This was a retrospective study of 33 adults with intractable mTLE who underwent left temporal lobe surgery at three different epilepsy surgery centers who also underwent pre-, and at least 6-month post-surgical neuropsychological testing. Measures included the Boston Naming Test (BNT) and the Engel Epilepsy Surgery Outcome Scale. Fisher's exact tests revealed a statistically significant decline in naming in ATLs compared to SLAHs, but no other significant group differences. 82% of ATL and 36% of subSAH patients showed a significant naming decline whereas no SLAH patient (0%) had a significant naming decline. Significant postoperative naming improvement was seen in 36% of SLAH patients in contrast to 9% improvement in subSAH patients and 0% improvement in ATLs. Finally, there were no statistically significant differences between surgical approaches with regard to seizure freedom outcome, although there was a trend towards better seizure relief outcome among the ATL patients. Results support a possible benefit of SLAH in preserving visual confrontation naming after left TLE surgery. While result interpretation is limited by the small sample size, findings suggest outcome is likely to differ by surgical approach, and that further research on cognitive and seizure freedom outcomes is needed to inform patients and providers of potential risks and benefits with each.

A Comparison of Neuropsychological Outcomes following Responsive Neurostimulation and Anterior Temporal Lobectomy in Drug-Resistant Epilepsy.

Neuropsychological outcomes following temporal lobe resection for drug-resistant epilepsy (DRE) are well established. For instance, left anterior temporal lobectomy (LATL) is associated with a greater risk for cognitive morbidity compared to right (RATL). However, the impact of neuromodulatory devices, specifically responsive neurostimulation (RNS), remains an area of active interest. There are currently no head-to-head comparisons of neuropsychological outcomes after surgical resection and neuromodulation. This study reports on a cohort of 21 DRE patients with the RNS System who received comprehensive pre- and post-implantation neuropsychological testing. We compared both cognitive and seizure outcomes in the RNS group to those of 307 DRE patients who underwent LATL (n = 138) or RATL (n = 169). RNS patients had higher seizure rates pre-intervention. While fewer in the RNS group achieved Class I Engel outcomes compared to the ATL cohorts, RNS patients also showed seizure frequency declines from pre- to post-intervention that were similar to those who underwent resective surgery. Moreover, the RNS and RATL groups were similar in their neuropsychological outcomes, showing no significant cognitive decline post-intervention. In contrast, the LATL group notably declined in object naming and verbal list learning. Direct comparisons like this study may be used to guide clinicians in shared decision making to tailor management plans for patients' overall treatment goals.

A Potential Risk of Radiation-Induced Cavernous Malformations Following Adjuvant Gamma Knife Radiosurgery for Mesial Temporal Lobe Epilepsy.

Objective: Several clinical studies have explored the feasibility and efficacy of radiosurgical treatment for mesial temporal lobe epilepsy, but the long-term safety of this treatment has not been fully characterized. This study aims to report and describe radiation-induced cavernous malformation as a delayed complication of radiosurgery in epilepsy patients. Methods: The series includes 20 patients with mesial temporal lobe epilepsy who underwent Gamma Knife radiosurgery (GKRS). The majority received a prescribed isodose of 24 Gy as an adjuvant treatment after anterior temporal lobectomy. Results: In this series, we identified radiation-induced cavernous malformation in three patients, resulting in a cumulative incidence of 18.4% (95% CI, 6.3 to 47.0%) at an eight-year follow-up. These late sequelae of vascular malformation occurred between 6.9 and 7.6 years after GKRS, manifesting later than other delayed radiation-induced changes, such as radiation necrosis. Neurological symptoms attributed to intracranial hypertension were present in those three cases involving cavernous malformation. Of these, two cases, which initially exhibited an insufficient response to radiosurgery, ultimately demonstrated seizure remission following the successful microsurgical resection of the cavernous malformation. Conclusion: All things considered, the development of radiation-induced cavernous malformation is not uncommon in this population and should be acknowledged as a potential long-term complication. Microsurgical resection of cavernous malformation can be preferentially considered in cases where the initial seizure outcome after GKRS is unsatisfactory.

Combined Depth and Subdural Electrodes for Lateralization of the Ictal Onset Zone in Mesial Temporal Lobe Epilepsy with Hippocampal Sclerosis.

(1) Objective: This study aimed to explore the efficacy of conventional invasive techniques in confirming unilateral seizure onset localization in mesial temporal lobe epilepsy with hippocampal sclerosis (MTLE-HS) and to investigate the association between electrode type and intracranial electroencephalography (EEG) pattern. (2) Methods: This retrospective study encompasses patients diagnosed with MTLE-HS who underwent an invasive study prior to an anterior temporal lobectomy (ATL). Intracranial EEG features were assessed for 99 seizure events from 25 selected patients who achieved seizure remission with ATL after an invasive study using bilateral combined depth and subdural electrodes. Their findings were compared to those of 21 seizure events in eight patients who exhibited suboptimal seizure outcomes. (3) Results: For the distribution of electrodes that recorded the ictal onset, hippocampal depth electrodes recorded 96% of all seizure events, while subdural electrodes recorded 52%. Among the seizures recorded in subdural electrodes, 49% were localized in medial electrodes, with only 8% occurring in lateral electrodes. The initiation of seizures exclusively detected in hippocampal depth electrodes was associated with successful seizure remission, whereas those solely recorded in the lateral strip electrodes were often linked to refractory seizures after ATL. (4) Conclusions: These findings emphasize the importance of employing a combination of depth and subdural electrodes in invasive studies for patients with MTLE-HS to enhance the accuracy of lateralization. This also cautions against sole reliance on subdural electrodes without depth electrodes, which could lead to inaccurate localization.

Drug-resistant temporal lobe epilepsy with temporal encephaloceles: How far to resect.

PURPOSE: This study sought to evaluate the impact of surgical extent on seizure outcome in drug-resistant temporal lobe epilepsy (DR-TLE) with temporal encephaloceles (TE). METHODS: This was a single-institution retrospective study of patients who underwent surgery for DR-TLE with TE between January 2008 and December 2020. The impact of surgical extent on seizure outcome was evaluated. In a subset with dominant DR-TLE, the impact of surgical extent on neuropsychometric outcome was evaluated. RESULTS: Thirty-four patients were identified (female, 56%; median age at surgery, 43 years). TE were frequently overlooked on initial magnetic resonance imaging (MRI), with encephaloceles only detected after repeat or expert re-review of MRI, additional multi-modal imaging, or intra-operatively in 31 (91%). Sixteen (47%) underwent limited resections, including encephalocele resection only (n = 5) and encephalocele resection with more extensive temporal corticectomy sparing the amygdala and hippocampus (n = 11). The remainder (n = 18, 53%) underwent standard anterior temporal lobectomy and amygdalohippocampectomy (ATLAH). Limited resection was performed more frequently on the left (12/17 vs. 4/17, p = 0.015). Twenty-seven patients (79%) had a favourable outcome (Engel I/II), and 17 (50%) were seizure-free at the last follow-up (median seizure-free survival of 27.3 months). There was no statistically significant difference in seizure-free outcomes between limited resection and ATLAH. In dominant DR-TLE, verbal memory decline was more likely after ATLAH than limited resection (3/4 vs. 0/9, p = 0.014). CONCLUSION: Expert re-review of imaging and multi-modal advanced imaging improved TE identification. There was no statistical difference in seizure-free outcomes based on surgical extent. Preservation of verbal memory supports limited resection in dominant temporal cases.

Avoidance of Pitfalls and Complications During Surgery for Temporal Lobe Epilepsy.

Anterior temporal lobectomy with amygdalohippocampectomy is the most common epilepsy surgery, which, in cases of mesial temporal lobe epilepsy caused by mesial temporal sclerosis, usually leads to improvements in seizure control, cognitive function, and quality of life. Nevertheless, while the primary goal of intervention is achieved in a large majority of patients, a small number of them, unfortunately, encounter complications. Some morbidity is nonspecific and may be noted after any craniotomy (e.g., surgical site infections, meningitis, bone flap osteomyelitis, and operative site or craniotomy-related hematomas). On the other hand, certain complications are specifically associated with surgery for temporal lobe epilepsy and can be discussed from the etiological standpoint: mechanical injuries of the brain; injury of eloquent neuronal structures; arterial and venous injuries; cerebral venous thrombosis; remote cerebellar hemorrhage; and postoperative hydrocephalus, seizures, and psychiatric disorders. In many cases, these complications are manifested in the early postoperative period by alterations of consciousness and a focal neurological deficit, and it may require immediate decisions on their appropriate management.

Postsurgical outcomes in a cohort of patients with hippocampal sclerosis: Initial experience in a referral epilepsy center in Peru.

Mesial temporal lobe epilepsy, one of the most common forms of epilepsy, is often linked with drug resistance. Surgical intervention is a reliable and safe treatment option, though research into postsurgical outcomes in our locality remains limited. We performed a retrospective observational study included 91 patients with mesial temporal lobe epilepsy and hippocampal sclerosis who had undergone anterior temporal lobectomy between 2012 and 2020 at a surgical epilepsy center located in Lima, Peru. Postoperative outcomes were analyzed using bivariate and multivariate analysis based on the Engel classification. We found that after 12 months of follow-up, 78.65% of the 91 patients achieved an Engel IA classification, while 9.09% attained Engel IB classification and 11.24% were designated as Engel II, with only 1.12% classified as Engel IVA. The median QOLIE31 score was 84 (IQR: 75-90), with 74.16% of the participants successfully reintegrating into academic or employment activities. After 24 months, only 68 patients completed the follow-up, with 69.12% achieving an Engel IA classification. Individuals with a secondary education or higher were more likely to achieve an Engel IA classification at 12 months (OR: 5.11; P = 0.005; CI: 1.63-16.01), after adjusting for sex and age. We concluded that most patients exhibited favorable outcomes after 1 year of follow-up. However, lower educational attainment was linked to worse postsurgical outcomes.

Surgical treatment of temporal lobe epilepsy: comparative results of selective amygdalohippocampectomy versus anterior temporal lobectomy from a referral center in Brazil / Tratamento cirúrgico da epilepsia do lobo temporal: resultados comparativos da amigdalohipocampectomia seletiva versus lobectomia temporal anterior em um centro de referência no Brasil

Abstract Background Temporal lobe epilepsy (TLE) is a high prevalence neurological disorder. Surgery has emerged as a promising treatment. Objective The objective of this work is to compare the surgical results of anterior temporal lobectomy (ATL) versus selective amygdalohippocampectomy (SAH) in a cohort of 132 patients. Methods We performed a retrospective study of 146 patients operated for TLE from 2008 to 2019. Initially, 13 patients were excluded from the study due to insufficient medical record data or follow-up loss. One patient was excluded from the analysis of the results due to death in the first postoperative week. We used the ILAE scale to classify seizure control after surgery. In patients with left hippocampal sclerosis, SAH was performed and in right temporal lobe epilepsy, ATL was the approach of choice. Results The mean follow-up time after surgery was 57.2 months (12-137). In our data analysis, we found that the group of patients undergoing ATL had a higher prevalence of being completely seizure-free (ILAE I) (57.1% versus 31%) and a higher rate of satisfactory seizure control (88.6% versus 69.3%) p = 0,006, when compared with patients undergoing SAH. Conclusions The literature is still controversial about seizure control concerning the technique used due to the lack of a robust methodology. Our data analysis identified the superiority of ATL over SAH in seizure outcomes. ATL may be the best option for adequately controlling seizures with minimal additional morbidity in countries with a cost limitation for extended propaedeutics.

Resumo Antecedentes A epilepsia do lobo temporal (TLE) é uma desordem neurológica de alta prevalência. A cirurgia surgiu como um tratamento promissor. Objetivo O objetivo deste trabalho é comparar os resultados da lobectomia temporal anterior (ATL) versus amigdalohipocampectomia seletiva (SAH) em uma coorte de 132 pacientes. Métodos Realizamos um estudo retrospectivo de 146 pacientes operados por TLE de 2008 a 2019. Inicialmente, 13 pacientes foram excluídos por insuficiência de dados em prontuário ou perda de seguimento. Um paciente foi excluído da análise por óbito na primeira semana de pós-operatório. Usamos a escala ILAE para classificar o controle das crises após a cirurgia. Em pacientes com esclerose hipocampal à esquerda, foi realizada a SAH, e na epilepsia do lobo temporal à direita, a ATL foi a abordagem de escolha. Resultados O tempo médio de seguimento após a cirurgia foi de 57,2 meses (12-137). Em nossa avaliação, encontramos que o grupo de pacientes submetidos à ATL apresentou maior prevalência de ausência total de crises (ILAE I) (57,1% versus 31%) e maior taxa de controle satisfatório da epilepsia (88,6% versus 69,3%) p = 0,006, quando comparado ao grupo submetido à SAH. Resultados A literatura ainda é controversa em relação à redução das crises de acordo com a técnica utilizada devido a falta de uma metodologia robusta. Nosso estudo identificou superioridade da ATL sobre a SAH nos desfechos convulsivos. ATL pode ser a melhor opção para controlar adequadamente as convulsões com morbidade adicional mínima em países com limitação de custo para propedêutica estendida.

A Consideration of Optimal Head Position in Transsylvian Selective Amygdalohippocampectomy.

Transsylvian selective amygdalohippocampectomy (TSA) is one of the predominant surgical options for drug-resistant mesial temporal lobe epilepsy. The purpose of this article is to highlight the unique features of TSA and determine the setting to perform safe and secure TSA with special reference to the optimal head position. TSA should be performed via a small surgical corridor in the temporal stem that contains functionally important fiber tracts, including the uncinate fasciculus, the inferior fronto-occipital fasciculus, and the optic radiation. Graphical simulations proposed that low-degree (<30°) head rotation had the advantage of sufficiently opening the surgical field in TSA and may help surgical procedures within the limited exposure of the medial temporal structures. Inspection of the surgical videos implied that the collapse of the inferior horn was prevented in low-degree rotation, probably because the deformation due to the brain shift was minimized in the medial temporal structures. A simulation also implied that chin-up position had the advantage of resecting the tail of the hippocampus in a straightforward manner. We suggest that the setting is optimized in TSA with low-degree rotation and chin-up head position.

Recovery of glymphatic system function in patients with temporal lobe epilepsy after surgery.

OBJECTIVES: To investigate the recovery of human glymphatic system (GS) function in patients with temporal lobe epilepsy (TLE) after successful anterior temporal lobectomy (ATL) using diffusion tensor image analysis along the perivascular space (DTI-ALPS). METHODS: We retrospectively analysed DTI-ALPS index in 13 patients with unilateral TLE before and after ATL, and compared the index with 20 healthy controls (HCs). Two-sample t tests and paired t tests were performed to analyse differences in the DTI-ALPS index between patients and HCs. The Pearson correlation analysis was used to observe the relationship between the disease duration and GS function. RESULTS: The DTI-ALPS index before ATL was significantly lower in the hemisphere ipsilateral to the epileptogenic foci than in the contralateral hemisphere of the patients (p < 0.001, t = - 4.81) and in the ipsilateral hemisphere of the HCs (p = 0.007, t = - 2.90). A significant increase in the DTI-ALPS index was found in the hemisphere ipsilateral to the epileptogenic foci after successful ATL (p = 0.01, t = - 3.01). In addition, the DTI-ALPS index of the lesion side before ATL was significantly correlated with disease duration (p = 0.04, r = - 0.59). CONCLUSIONS: DTI-ALPS may be used as a quantitative biomarker evaluating surgical outcomes and TLE disease duration. DTI-ALPS index may also help localise epileptogenic foci in unilateral TLE. Overall, our study suggests that GS may potentially serve as a new method for the management of TLE and a new direction for investigating the mechanism of epilepsy. KEY POINTS: • DTI-ALPS index may contribute to epileptogenic foci lateralisation in TLE. • DTI-ALPS index is a potential quantitative feature evaluating surgical outcomes and TLE disease duration. • The GS provides a new perspective for the study of TLE.

Temporal Encephalocele: A Treatable Etiology of Drug-Resistant Pediatric Temporal Lobe Epilepsy.

BACKGROUND: Temporal lobe encephaloceles (TEs) are a rare cause of drug-resistant temporal lobe epilepsy (DR-TLE), with head trauma and obesity identified as risk factors in adults. This study evaluated the clinical characteristics of childhood-onset DR-TLE due to TE. METHODS: This is a single-institution retrospective review of childhood-onset DR-TLE with radiographic TE identified between 2008 and 2020. The epilepsy history, brain imaging features, and surgical outcomes were collected. RESULTS: Eleven children with DR-TLE due to TE were included (median age at epilepsy onset was 11 years, interquartile range 8.5 to 13.5 years). Median latency between epilepsy diagnosis and TE detection was 3 years (range of 0 to 13 years). None had history of head trauma. Body mass index greater than 85 percentile for age and sex was seen in 36% of the children. No patient had bilateral TE identified. TEs were diagnosed based on epilepsy surgery conference re-review of imaging in 36% of cases. All herniations were contained defects without osseous dehiscence. Regional fluorodeoxyglucose (FDG) hypometabolism ipsilateral to the encephalocele was seen in all children who had FDG-positron emission tomography (PET) of the brain. Of the children who had surgery, 70% were seizure free or had nondisabling seizures at last follow-up (mean follow-up 52 months). CONCLUSIONS: TE is a surgically remediable etiology of DR-TLE in childhood. TEs are often overlooked at pediatric epilepsy diagnosis, calling for the need to increase awareness of this entity. FDG-PET temporal hypometabolism in children with presumed nonlesional DR-TLE should be carefully examined for occult TEs.

Epilepsy surgery for dominant-side mesial temporal lobe epilepsy without hippocampal sclerosis.

Although anterior temporal lobectomy (ATL) is an established surgery for medically intractable mesial temporal lobe epilepsy (MTLE), it can harm memory function, especially in dominant-side MTLE patients without hippocampal sclerosis (HS). To avoid this complication, multiple hippocampal transection (MHT) was developed, but its efficacy has not been fully elucidated. We report the detailed treatment results of MHT compared with that of ATL. We retrospectively analysed the records of 30 patients who underwent surgery for dominant-side MTLE. ATL was completed for 23 patients with HS, and MHT was completed for 7 patients without HS. The seizure control status, number of anti-seizure medicines, neurocognitive function, and psychiatric disorders of each patient were reviewed. The mean follow-up period was 70 months. Seizure control of Engel class I was achieved in 16 patients (70%) in the ALT group versus 5 patients (71%) in the MHT group. The mean number of anti-seizure medicines administered in the ATL group changed significantly from 2.4 to 1.9 (p = 0.01), while that in the MHT group was unchanged (from 2.1 to 2.0, p = 0.77). Eleven patients (48%) in the ATL group developed psychiatric disorders during the postoperative follow-up period, whereas no psychological complications were observed in the MHT group. Neither group showed neurocognitive decline after the surgery in any of the WAIS-III or WMS-R subtests. In conclusion, MHT may achieve reasonable postoperative seizure reduction, preserve neurocognitive function, and reduce postoperative psychiatric complications. Therefore, it can be considered as a therapeutic option for dominant-side MTLE without HS.

[ Delay time from diagnosis to surgery in drug-resistant epilepsy]. / Tiempo de retraso desde el diagnóstico hasta la cirugía en la epilepsia refractaria.

Drug-resistant epilepsy, in a good number of cases, can benefit from surgery. It is essential to make a timely referral for the pre-surgical study. We retrospectively reviewed the clinical records of our center from 2011 to 2019. The patients who underwent temporal lobectomy were selected. After performing the data analysis, an average waiting time of 23 years was observed, similar to that observed in other countries of the American continent. There is an evident need to provide strategies to reduce the waiting time for epilepsy surgery in patients who benefit from the intervention.

La epilepsia refractaria, en una buena parte de los casos, puede beneficiarse de cirugía. Es importante realizar una referencia oportuna para el estudio prequirúrgico. Se revisaron de forma retrospectiva los registros clínicos de nuestro centro desde el año 2011 al 2019 y se seleccionaron a los pacientes sometidos a lobectomía temporal. Tras realizar el análisis de los datos se objetivó un tiempo de espera medio de 23 años, similar a lo observado en otros países del continente americano. Existe una necesidad evidente de proporcionar estrategias para disminuir el tiempo de espera para la cirugía de epilepsia en los pacientes que se beneficien de la intervención.

Sleep macrostructure and cyclic alternating pattern in patients who underwent surgery for hippocampal sclerosis: A prospective controlled polysomnographic study.

INTRODUCTION: Temporal lobe epilepsy due to hippocampal sclerosis (TLE-HS) is one of the most common drug-resistant epilepsy. Surgery is currently accepted as an effective and safe therapeutic approach compared to antiseizure medications (ASMs). The study aims to evaluate the effect of surgical treatment of TLE-HS on sleep profile and architecture by subjective and objective evaluation of sleep in basal condition after one month and one year. METHODS: Thirteen patients with TLE-HS were recruited to undergo overnight polysomnography and a subjective evaluation of nocturnal sleep utilizing the Pittsburgh Sleep Quality Index (PSQI) and daytime somnolence through the Epworth Sleepiness Scale (ESS) in basal condition (T0), one month (T1) and one year after surgery (T2), respectively. Thirteen healthy controls (HC) matched for age, sex and BMI were recruited. Scoring and analysis of sleep macrostructure and cyclic alternating pattern (CAP) parameters were performed. RESULTS: The comparison between patients in basal condition (T0) and HC showed a significant lower sleep efficiency (p = 0.003) and REM percentage (p < 0.001). Regarding CAP, patients at T0 showed higher total CAP rate (p < 0.001), CAP rate in N2 (p < 0.001), higher A3 (%) (p = 0.001), higher mean duration of A1 (p = 0.002), A3 index (p < 0.001), cycle in sequences (p < 0.001), lower B duration (p < 0.001), cycle mean duration (p < 0.001) than HC. Surgery did not induce significant changes in nocturnal macrostructural polysomnographic variables in T1 and T2. Lower CAP rate (T1 vs T0 and T2 vs T0 p < 0.001), CAP rate in N3 (T1 vs T0 and T2 vs T0 p < 0.001), A3 (%) (T1 vs T0 and T2 vs T0 p < 0.001); lower phase A2 index (T1 vs T0 p < 0.001) and A3 index (T1 vs T0 p < 0.001), lower phase A1 index (T2 vs T0 p < 0.001) and cycle in sequences (T2 vs T0 p = 0.002) higher B mean duration (T2 vs T0 p = 0.002). No significant differences were found between T1 and T2 in CAP parameters. CONCLUSION: We found a significant NREM sleep instability in patients with TLE-HS compared with HC. In addition, anterior temporal lobectomy (ATL) induced a significant improvement in sleep continuity as evaluated by cyclic alternating pattern already one month later and this effect persisted after one year. ALT seems to restore a more resilient sleeping brain.

Altered Resting State Networks Before and After Temporal Lobe Epilepsy Surgery.

OBJECTIVES: To explore the resting state networks (RSNs) alterations in patients with unilateral mesial temporal lobe epilepsy (mTLE) before and after successful surgery. METHODS: Resting-state functional MRI and T1-weighted structural MRI were obtained in 37 mTLE patients who achieved seizure freedom after anterior temporal lobectomy. Patients were scanned before surgery and at two years after surgery. Twenty-eight age- and sex-matched healthy controls were scanned once. Functional connectivity (FC) changes within and between ten common RSNs before and after surgery, and FC changes between hippocampus and RSNs were explored. RESULTS: Before surgery, decreased FC was found within visual network and basal ganglia network, while after surgery, FC within basal ganglia network further decreased but FC within sensorimotor network and dorsal attention network increased. Before surgery, between-network FC related to basal ganglia network, visual network and dorsal attention network decreased, while between-network FC related to default mode network increased. After surgery, between-network FC related to visual network and dorsal attention network significantly increased. In addition, before surgery, ipsilateral hippocampus showed decreased FC with visual network, basal ganglia network, sensorimotor network, default mode network and frontoparietal network, while contralateral rostral hippocampus showed increased FC with salience network. After surgery, no obvious FC changes were found between contralateral hippocampus and these RSNs. CONCLUSION: MTLE patients showed significant RSNs alterations before and after surgery. Basal ganglia network showed progressive decline in functional connectivity. Successful surgery may lead to RSNs reorganization. These results provide preliminary evidence for postoperative functional remodeling at whole-brain-network level.

Magnetic resonance imaging-guided laser interstitial thermal therapy for refractory focal epilepsy in a patient with a fully implanted RNS system: illustrative case.

BACKGROUND: The resective surgery plus responsive neurostimulation (RNS) system is an effective treatment for patients with refractory focal epilepsy. Furthermore, the long-term intracranial electroencephalography data provided by the system can inform a future resection or ablation procedure. RNS patients may undergo 1.5-T magnetic resonance imaging (MRI) under the conditions specified in the RNS system MRI guidelines; however, it was unknown if the MRI artifact would limit intraoperative laser interstitial thermal therapy (LITT) in a patient with a fully implanted RNS system. OBSERVATIONS: The authors were able to complete a successful awake LITT of epileptogenic tissue in a 1.5-T MRI scanner on the ipsilateral side to an implanted RNS system. LESSONS: If a future LITT procedure is probable, the neurostimulator should be placed contralateral to the side of the potential ablation. Using twist drill holes versus burr holes for depth lead placement may assist in future laser bone anchor seating. Before a LITT procedure in a patient with the neurostimulator ipsilateral to the ablation, 1.5-T MRI thermography scanning should be scheduled preoperatively to assess artifact in the proposed ablation zone. Per the RNS system MRI guidelines, the patient must be positioned supine and awake, with no more than 30 minutes of active scan time before a 30-minute pause.