Selective Amygdalohippocampectomy Research Articles

Results of surgical treatment for drug-resistant temporal epilepsy and related predictors of negative post-surgery outcome

Objective: to evaluate the results of surgical treatment and identify related predictors of unfavorable outcome in patients with temporal drug-resistant epilepsy (DRE) in long-term postoperative period.Material and methods. Fifty-one patients with temporal lobe DRE were examined using clinical, neuroimaging, electro- physiological, and laboratory research methods from June 2020 to June 2023. Anteromedial temporal lobectomy (AMLE) and selective amygdalohippocampectomy (SAHE) were performed in 38 (74.5%) and 13 (25.5%) cases, respectively. Postsurgery outcomes were evaluated in 51 patients 6 months later, continued in 43 and 20 patients 1 year and 2 years, respectively, afterwards.Results. The percentage of patients with significant improvement (Engel I/II) 6 months, 1 year and 2 years post-surgery was 82.4%, 72.1%, and 55.0%, respectively. After AMLE vs. SAHE, patients had a more favorable outcome while assessing seizure control. The predictors of unfavorable post-surgery outcome included a prolonged epilepsy course before surgery, the presence of electroencephalography-verified epileptiform activity in postoperative period, and repeated surgical intervention. Patient age, the presence of focal seizures evolving into bilateral tonic-clonic seizures as well as more frequent seizures before surgery were considered as potential predictors.Conclusion. The study results show that quite high effectiveness of seizure control in postoperative period in temporal DRE is quite high that may be accounted for by probability of removing epileptogenic foci and suppression of the mechanisms ensuring emergence and irritation of epileptic discharges. Nevertheless, effectiveness of surgical treatment fades off with time, which requires to further investigate the negative factors countering long-term post-surgery effect. In connection with this, a special attention should be paid to factors such as the presence of electroencephalography-verified epileptiform activity in postoperative period, repeated surgical intervention as well as prolonged epilepsy before surgery.

Association Between Postsurgical Functional Connectivity and Seizure Outcome in Patients With Temporal Lobe Epilepsy.

Despite the success of presurgical network connectivity studies in predicting short-term (1-year) seizure outcomes, later seizure recurrence occurs in some patients with temporal lobe epilepsy (TLE). To uncover contributors to this recurrence, we investigated the relationship between functional connectivity and seizure outcomes at different time points after surgery in these patients. Patients included were clinically diagnosed with unilateral mesial TLE after a standard clinical evaluation and underwent selective amygdalohippocampectomy. Healthy controls had no history of seizures or head injury. Using resting-state fMRI, we assessed the postsurgical functional connectivity node strength, computed as the node's total strength to all other nodes, between seizure-free (Engel Ia-Ib) and nonseizure-free (Engel Ic-IV) acquisitions. The change over time after surgery in different outcome groups in these nodes was also characterized. Patients with TLE (n = 32, mean age: 43.1 ± 11.9 years; 46.8% female) and 85 healthy controls (mean age: 37.7 ± 13.5 years; 48.2% female) were included. Resting fMRI was acquired before surgery and at least once after surgery in each patient (range 1-4 scans, 5-60 months). Differences between patients with (n = 30) and without (n = 18) seizure freedom were detected in the posterior insula ipsilateral to the resection (I-PIns: 95% CI -154.8 to -50.1, p = 2.8 × 10-4) and the bilateral central operculum (I-CO: 95% CI -163.2 to -65.1, p = 2.6 × 10-5, C-CO: 95% CI -172.7 to -55.8, p = 2.8 × 10-4). In these nodes, only those who were seizure-free had increased node strength after surgery that increased linearly over time (I-CO: 95% CI 1.0-5.2, p = 4.2 × 10-3, C-CO: 95% CI 1.0-5.2, p = 5.5 × 10-3, I-PIns: 95% CI 1.6-5.5, p = 0.9 × 10-3). Different outcome groups were not distinguished by node strength before surgery. The findings suggest that network evolution in the first 5 years after selective amygdalohippocampectomy surgery is related to seizure outcomes in TLE. This highlights the need to identify presurgical and surgical conditions that lead to disparate postsurgical trajectories between seizure-free and nonseizure-free patients to identify potential contributors to long-term seizure outcomes. However, the lack of including other surgical approaches may affect the generalizability of the results.

Selective Amygdalohippocampectomy versus Anterior Temporal Lobectomy in Mesial Temporal Lobe Epilepsy: A Meta-Analysis of Seizure Control and Cognitive Outcomes

Background: Mesial temporal lobe epilepsy (MTLE) is a common form of drug-resistant epilepsy often necessitating surgical intervention. The choice between selective amygdalohippocampectomy (SelAH) and anterior temporal lobectomy (ATL) remains a subject of debate, with each procedure offering potential advantages and disadvantages in terms of seizure control and cognitive outcomes. Methods: A comprehensive literature search was conducted across PubMed, Scopus, and Springer databases to identify studies published between 2013 and September 2024 that compared SELAH and ATL in patients with MTLE. The primary outcomes of interest were seizure freedom rates and changes in cognitive function, particularly IQ scores. A meta-analysis was performed using a random-effects model to pool the results of included studies. Results: The meta-analysis encompassed 5 studies involving 218 patients with MTLE (105 underwent SelAH, 113 underwent ATL). The pooled results demonstrated a statistically significant reduction in the odds of achieving seizure freedom following ATL compared to SelAH (odds ratio [OR] 0.38, 95% confidence interval [CI] 0.24-0.81, p = 0.008). Regarding cognitive outcomes, no significant difference was observed in Performance IQ (PIQ) between the two groups. However, a trend towards improved Verbal IQ (VIQ) was noted in the SelAH group, although this did not reach statistical significance. Conclusion: The findings suggest that SelAH may offer superior seizure control compared to ATL in patients with MTLE. While both procedures appear to have comparable effects on PIQ, SelAH may be associated with a trend towards better preservation or even improvement in VIQ. The choice between SelAH and ATL should be individualized based on patient-specific factors, including preoperative cognitive profile and the relative importance of seizure control versus cognitive preservation.

Deep brain stimulation of hippocampus in treatment of refractory temporal lobe epilepsy.

Temporal lobe epilepsy (TLE) is the most common cause of focal onset seizures, affecting 40% of adolescents and adults with epilepsy. TLE is also one of the most common drug resistant forms of epilepsy. Surgical resection remains the treatment of choice for TLE, but not all patients with TLE are suitable candidates for resective neurosurgery. For such patients, deep brain stimulation (DBS) of the hippocampus remains a reversible and efficient treatment alternative. We undertook a systematic review of the literature on hippocampal DBS efficacy and safety in the management of patients with TLE. A search using two electronic databases, the Medical Literature, Analysis, and Retrieval System on-line (MEDLINE) and the Cochrane Central Register of Controlled Trials (CEN-TRAL), was conducted. We found 14 articles related to hippocampal DBS for the treatment of TLE. The responder rate (defined as at least 50% reduction in seizure frequency) for all patients was 83.4%, Of 99 patients treated by hippocampal DBS, 82 were regarded as responders, and 17 as non-responders. Hippocampal DBS appears to be a safe and efficacious treatment alternative for patients who are not candidates for temporal lobectomy or selective amygdalohippocampectomy due to serious postoperative cognitive deficits. In selected patients with TLE, this neuromodulatory therapy may be very safe and efficacious.

Transsylvian transopercular peri-central core hemispherotomy for treating epilepsy: anatomy, surgical technique, and clinical outcome.

The objective of this study was to display the anatomical landmarks, surgical technique, and clinical outcome of transsylvian transopercular peri-central core hemispherotomy (TTPH) for treating refractory epilepsy. From 2011 to 2023, 26 patients (12 with Rasmussen syndrome, 8 with hemimegalencephaly/cortical malformations, and 6 with hypoxic-ischemic encephalopathy; mean [range] age 11.3 years [16 months to 35 years]; 13 females; and 13 with right-side pathology) underwent TTPH. The mean (range) follow-up was 88 (14-156) months. The intradural surgical time, use and amount of blood transfusion, postoperative fever, hospital stay, weight at surgery, and seizure onset to surgery interval are reported. TTPH consists of 1) sylvian fissure opening, 2) coagulation of the M2 and M3 branches, 3) frontoparietal opercula removal, 4) suprainsular resection, 5) insula removal, 6) selective amygdalohippocampectomy, 7) disconnection of the posterior temporal and occipital lobes using the tentorium and falx as landmarks, 8) intraventricular callosotomy, and 9) disconnection of the basal frontal lobe. In cortical malformation, the gray-white matter interface serves as a landmark. The average intradural operating time was 7 hours 18 minutes (3 hours 33 minutes to 13 hours 45 minutes); all patients were Engel class I; and 2 patients presented with procedure-related complications (meningitis and transient abducens nerve palsy). No patient required shunt surgery or reoperation. TTPH offers anatomical landmarks as intraoperative guides and has achieved good seizure control and low complication rates.

AB076. Underutilization of epilepsy surgery in Pakistan: 10-year experience from the only comprehensive epilepsy center in the country.

Eighty percent of the global epilepsy burden is borne by developing countries, and 30% of these patients have drug-resistant epilepsy (DRE). Epilepsy surgery (ES) can significantly improve the cognition and quality of life in DRE. A comprehensive epilepsy center was established in Pakistan in 2010, the only facility for ES in a country of 231 million people. Hundreds of epilepsy patients are medically managed at the center each year. We aimed to study seizure control in all ES cases performed at the only comprehensive epilepsy center in the country during last 10 years. It was a retrospective cohort study. Medical records of all cases of ES performed at our center from 2012 to 2021 were retrieved, through the Hospital's Information Management System. Patients were also contacted via phone calls where needed, to collect information about their seizure control as per Engel Classification. Data was analyzed using SPSSv21. Thirty-three surgeries including 10 temporal lobectomies with amygdalohippocampectomy, 11 selective amygdalohippocampectomies, 9 corpus callosotomies, 1 callosotomy with lesionectomy, 1 lesionectomy and 1 temporal lobectomy were performed. The median age of patients was 23: [18-31] years. Complex partial seizures were most common (14; 42.4%), followed by generalized seizures (10; 30.3%). The median duration of AEDs before surgery was 6 (IQR: 3.25-13.75) years. Eighteen (54.5%) patients had complete freedom from disabling seizures (Engel Class IA) at a median follow-up of 3.25 (IQR: 1.12-6) years. All patients continued to receive antiepileptic drugs after surgery, and all procedures had nearly 50% optimum seizure control outcomes. The clinical outcomes of ES performed at our center are consistent with evidence. However, the small volume highlights the underutilization of this extremely important service. More studies are needed to identify the factors responsible for this disparity, so that all DRE patients have access to ES.

Selective amygdalohippocampectomy via the paramedian supracerebellar-transtentorial approach for mediobasal temporal epilepsy.

Selective amygdalohippocampectomy via the pterional transsylvian approach is a feasible option for many patients with mediobasal temporal epilepsy. However, it may be insufficient for patients when the posterior hippocampal region is involved. The paramedian supracerebellar transtentorial approach offers precise anatomical orientation when exposing the entire length of the mediobasal temporal region, including the fusiform gyrus. In addition, this approach allows selective amygdalohippocampectomy without any neocortical damage. This video presents the successful treatment of a patient with posterior hippocampal sclerosis and mediobasal temporal epilepsy through the paramedian supracerebellar transtentorial approach.

Which parameters influence cognitive, psychiatric and long-term seizure outcome in mesial temporal lobe epilepsy after selective amygdalohippocampectomy?

BackgroundWe aimed to analyze potentially prognostic factors which could have influence on postoperative seizure, neuropsychological and psychiatric outcome in a cohort of patients with mesial temporal lobe epilepsy (MTLE) due to hippocampal sclerosis (HS) after selective amygdalohippocampectomy (SAHE) via transsylvian approach.MethodsClinical variables of 171 patients with drug-resistant MTLE with HS (88 females) who underwent SAHE between 1994 and 2019 were evaluated using univariable and multivariable logistic regression models, to investigate which of the explanatory parameters can best predict the outcome.ResultsAt the last available follow-up visit 12.3 ± 6.3 years after surgery 114 patients (67.9%) were seizure-free. Left hemispheric MTLE was associated with worse postoperative seizure outcome at first year after surgery (OR = 0.54, p = 0.01), female sex—with seizure recurrence at years 2 (OR = 0.52, p = 0.01) and 5 (OR = 0.53, p = 0.025) and higher number of preoperative antiseizure medication trials—with seizure recurrence at year 2 (OR = 0.77, p = 0.0064), whereas patients without history of traumatic brain injury had better postoperative seizure outcome at first year (OR = 2.08, p = 0.0091). All predictors lost their predictive value in long-term course. HS types had no prognostic influence on outcome. Patients operated on right side performed better in verbal memory compared to left (VLMT 1-5 p < 0.001, VLMT 7 p = 0.001). Depression occurred less frequently in seizure-free patients compared to non-seizure-free patients (BDI-II Z = − 2.341, p = 0.019).ConclusionsSAHE gives an improved chance of achieving good postoperative seizure, psychiatric and neuropsychological outcome in patients with in MTLE due to HS. Predictors of short-term outcome don’t predict long-term outcome.

Indirect structural changes and reduced controllability after temporal lobe epilepsy resection.

To understand the potential behavioral and cognitive effects of mesial temporal resection for temporal lobe epilepsy (TLE) a method is required to characterize network-wide functional alterations caused by a discrete structural disconnection. The objective of this study was to investigate network-wide alterations in brain dynamics of patients with TLE before and after surgical resection of the seizure focus using average regional controllability (ARC), a measure of the ability of a node to influence network dynamics. Diffusion-weighted imaging (DWI) data were acquired in 27 patients with drug-resistant unilateral mesial TLE who underwent selective amygdalohippocampectomy. Imaging data were acquired before and after surgery and a presurgical and postsurgical structural connectome was generated from whole-brain tractography. Edge-wise strength, node strength, and node ARC were compared before and after surgery. Direct and indirect edge-wise strength changes were identified using patient-specific simulated resections. Direct edges were defined as primary edges disconnected by the resection zone itself. Indirect edges were secondary measured edge strength changes. Changes in node strength and ARC were then related to both direct and indirect edge changes. We found nodes with significant postsurgical changes in both node strength and ARC surrounding the resection zone (paired t tests, p < .05, Bonferroni corrected). ARC identified additional postsurgical changes in nodes outside of the resection zone within the ipsilateral occipital lobe, which were associated with indirect edge-wise strength changes of the postsurgical network (Fisher's exact test, p < .001). These indirect edge-wise changes were facilitated through the "hub" nodes including the thalamus, putamen, insula, and precuneus. Discrete network disconnection from TLE resection results in widespread structural and functional changes not predicted by disconnection alone. These can be well characterized by dynamic controllability measures such as ARC and may be useful for investigating changes in brain function that may contribute to seizure recurrence and behavioral or cognitive changes after surgery.

Region-specific MRI predictors of surgical outcome in temporal lobe epilepsy

ObjectiveIn drug-resistant temporal lobe epilepsy (TLE), it is not well-established in how far surgery should target morphological anomalies to achieve seizure freedom. Here, we assessed interactions between structural brain compromise and surgery to identify region-specific predictors of seizure outcome. MethodsWe obtained pre- and post-operative 3D T1-weighted MRI in 55 TLE patients who underwent selective amygdalo-hippocampectomy (SAH) or anterior temporal lobectomy (ATL) and 40 age and sex-matched healthy subjects. We measured surface-based morphological alterations of the mesiotemporal lobe structures (hippocampus, amygdala, entorhinal and piriform cortices), the neocortex and the thalamus on both pre- and post-operative MRI. Using precise co-registration, in each patient we mapped the surgical cavity onto the MRI acquired before surgery, thereby quantifying the amount of pathological tissue resected; these features, together with the preoperative morphometric data, served as input to a supervised classification algorithm for postsurgical outcome prediction. ResultsOn pre-operative MRI, patients who became seizure-free (TLE-SF) presented with severe ipsilateral amygdalar and hippocampal atrophy, while not seizure-free patients (TLE-NSF) displayed amygdalar hypertrophy. Stratifying patients based on the surgical approach, post-operative MRI showed similar patterns of mesiotemporal and thalamic changes, but divergent neocortical thinning affecting the parieto-temporo-occipital regions following ATL and the frontal lobes after SAH. Irrespective of the surgical approach, hippocampal atrophy on pre-operative MRI and its extent of resection were the most predictive features of seizure-freedom in 89% of patients (selected 100% across validations). SignificanceOur study indicates a critical role of the extent of resection of MRI-derived hippocampal morphological anomalies on seizure outcome. Precise pre-operative quantification of the mesiotemporal lobe provides non-invasive prognostics for individualized surgery.

Microsurgery for drug resistance epilepsy due to temporal lobe lesions in a resource limited condition: a cross-sectional study.

The study was a retrospective and prospective cross-sectional study of 35 cases of drug-resistant temporal lobe epilepsy. All patients were operated on by the primary author between May 2018 and September 2022. The study evaluated various factors including clinical characteristics, electroencephalogram, magnetic resonance imaging, surgical outcomes, and histopathology. The success rate of the surgeries (74.3%) is similar to those reported in high-income countries. 51.4% underwent selective amygdalohippocampectomy for cases that localized to the mesial temporal lobe. Lateral/neocortical lesions underwent lesionectomy (48.6%). Our study found a complication rate of 17.1%: meningitis (8.5%), trainset focal paralysis (2.9%), and soft tissue infection (5.7%). There were no mortalities. The article showcases an international collaborative effort that demonstrates the possibility of providing highly effective and safe surgical care for temporal lobe epilepsy even in low-resource environments. The authors hope that this model can be replicated in other areas with similar resource limitations.

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.

Surgical treatment of temporal lobe epilepsy: comparative results of selective amygdalohippocampectomy versus anterior temporal lobectomy from a referral center in Brazil.

Temporal lobe epilepsy (TLE) is a high prevalence neurological disorder. Surgery has emerged as a promising treatment. 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. 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. 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. 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.

P.096 Effectiveness of palliative focal resective surgery in intracranial EEG confirmed multifocal intractable epilepsy in adult patients

Background: Effectiveness of “palliative resections” of a dominant epileptogenic focus in adults with multifocal intractable epilepsy confirmed on intracranial EEG has rarely been reported. Methods: We retrospectively reviewed our database to identify patients who underwent focal resection after confirmation of multiple seizure foci on intracranial EEG. Results of presurgical investigations, intracranial EEG, procedures, complications and outcome were collected. Results: A total of 17 patients underwent palliative resection (8 left, 9 right). Preoperative MRI revealed malformations of cortical development in 6 patients, and MTS in 6 patients. Intracranial stereo EEG revealed 8 bilateral and 9 unilateral multifocal epileptogenic foci. Surgical procedures included anterior temporal lobectomy (ATL) or selective amygdalohippocampectomy in 4 patients, ATL plus additional cortical resection in 7 patients, and extratemporal resection in 6 patients. One patient had dysphasia post ATL and a second patient had worsened cognitive dysfunction post extended frontal lobectomy. Favorable seizure outcome (Engel class I and II) was achieved in 10 patients (58.8%). Pathology revealed focal cortical dysplasia in 6 patients and hippocampal sclerosis in 5 patients. Conclusions: Palliative resection of a dominant epileptogenic focus confirmed by intracranial EEG is effective in carefully selected adult cases of intractable epilepsy, particularly in patients with lesional epilepsy.

Transuncal Selective Amygdalohippocampectomy by an Inferolateral Preseptal Endoscopic Approach Through Inferior Eyelid Conjunctival Incision: An Anatomic Study.

Transorbital endoscopic approaches have been described for pathologies of anterior and middle fossae. Standard lateral orbitotomy gives access to mesial temporal lobe, but the axis of work is partially obscured by the temporal pole and working corridor is limited. To evaluate the usefulness of an inferolateral orbitotomy to provide a more direct corridor to perform a transuncal selective amygdalohippocampectomy. Three adult cadaveric specimens were used for a total of 6 dissections. A step-by-step description and illustration of the transuncal corridor for a selective amygdalohippocampectomy were performed using the inferolateral orbitotomy through an inferior eyelid conjunctival incision. The anatomic landmarks were demonstrated in detail. Orbitotomies and angles of work were measured from computed tomography scans, and the area of resection was illustrated by postdissection MRI. Inferior eyelid conjunctival incision was made for exposure of the inferior orbital rim. Inferolateral transorbital approach was performed to access the transuncal corridor. Endoscopic selective amygdalohippocampectomy was performed through the entorhinal cortex without damage to the temporal neocortex or Meyer's loop. The mean horizontal diameter of the osteotomy was 14.4 mm, and the vertical one was 13.6 mm. The mean angles of work were 65° and 35.5° in the axial and sagittal planes, respectively. Complete amygdalohippocampectomy was achieved in all 6 dissections. Transuncal selective amygdalohippocampectomy was feasible in cadaveric specimens using the inferolateral transorbital endoscopic approach avoiding damage to the temporal neocortex and Meyer's loop. The inferior eyelid conjunctival incision may result in an excellent cosmetic outcome.

Remote effects of temporal lobe epilepsy surgery: Long-term morphological changes after surgical resection.

Epilepsy surgery is an effective treatment for drug-resistant patients. However, how different surgical approaches affect long-term brain structure remains poorly characterized. Here, we present a semiautomated method for quantifying structural changes after epilepsy surgery and compare the remote structural effects of two approaches, anterior temporal lobectomy (ATL), and selective amygdalohippocampectomy (SAH). We studied 36 temporal lobe epilepsy patients who underwent resective surgery (ATL = 22, SAH = 14). All patients received same-scanner MR imaging preoperatively and postoperatively (mean 2 years). To analyze postoperative structural changes, we segmented the resection zone and modified the Advanced Normalization Tools (ANTs) longitudinal cortical pipeline to account for resections. We compared global and regional annualized cortical thinning between surgical treatments. Across procedures, there was significant cortical thinning in the ipsilateral insula, fusiform, pericalcarine, and several temporal lobe regions outside the resection zone as well as the contralateral hippocampus. Additionally, increased postoperative cortical thickness was seen in the supramarginal gyrus. Patients treated with ATL exhibited greater annualized cortical thinning compared with SAH cases (ATL: -0.08 ± 0.11 mm per year, SAH: -0.01 ± 0.02 mm per year, t = 2.99, P = 0.006). There were focal postoperative differences between the two treatment groups in the ipsilateral insula (P = 0.039, corrected). Annualized cortical thinning rates correlated with preoperative cortical thickness (r = 0.60, P < 0.001) and had weaker associations with age at surgery (r = -0.33, P = 0.051) and disease duration (r = -0.42, P = 0.058). Our evidence suggests that selective procedures are associated with less cortical thinning and that earlier surgical intervention may reduce long-term impacts on brain structure.

Burr hole microsurgical subtemporal selective amygdalohippocampectomy.

At present, selective amygdalohippocampectomy (SAH) has become popular in the treatment of drug-resistant mesial temporal lobe epilepsy (TLE). However, there is still an ongoing discussion about the advantages and disadvantages of this approach. The study included a consecutive series of 43 adult patients with drug-resistant TLE, involving 24 women and 19 men (1.8/1). Surgeries were performed at the Burdenko Neurosurgery Center from 2016 to 2019. To perform subtemporal SAH through the burr hole with the diameter of 14mm, we used two types of approaches: preauricular, 25 cases, and supra-auricular, 18 cases. The follow-up ranged from 36 to 78months (median 59months). One patient died 16months after surgery (accident). By the third year after surgery, Engel I outcome was achieved in 80.9% (34 cases) of cases and Engel II in 4 (9.5%) and Engel III and Engel IV in 4 (9.6%) cases. Among the patients with Engel I outcomes, anticonvulsant therapy was completed in 15 (44.1%), and doses were reduced in 17 (50%) cases. Verbal and delayed verbal memory decreased after surgery in 38.5% and 46.1%, respectively. Verbal memory was mainly affected by preauricular approach in comparison with supra-auricular (p = 0.041). In 15 (51.7%) cases, minimal visual field defects were detected in the upper quadrant. At the same time, visual field defects did not extend into the lower quadrant and inside the 20° of the upper affected quadrant in any case. Burr hole microsurgical subtemporal SAH is an effective surgical procedure for drug-resistant TLE. It involves minimal risks of loss of visual field within the 20° of the upper quadrant. Supra-auricular approach, compared to preauricular, results in a reduction in the incidence of upper quadrant hemianopia and is associated with a lower risk of verbal memory impairment.

Visual outcomes after anterior temporal lobectomy and transsylvian selective amygdalohippocampectomy: A quantitative comparison of clinical and diffusion data.

Anterior temporal lobectomy (ATL) and transsylvian selective amygdalohippocampectomy (tsSAHE) are effective treatment strategies for intractable temporal lobe epilepsy but may cause visual field deficits (VFDs) by damaging the optic radiation (OpR). Due to the OpR's considerable variability and because it is indistinguishable from surrounding tissue without further technical guidance, it is highly vulnerable to iatrogenic injury. This imaging study uses a multimodal approach to assess visual outcomes after epilepsy surgery. We studied 62 patients who underwent ATL (n=32) or tsSAHE (n=30). Analysis of visual outcomes was conducted in four steps, including the assessment of (1) perimetry outcome (VFD incidence/extent, n=44/40), (2) volumetric OpR tractography damage (n=55), and the (3) relation of volumetric OpR tractography damage and perimetry outcome (n=35). Furthermore, (4) fixel-based analysis (FBA) was performed to assess micro- and macrostructural changes within the OpR following surgery (n=36). Altogether, 56% of all patients had postoperative VFDs (78.9% after ATL, 36.36% after tsSAHE, p=.011). VFDs and OpR tractography damage tended to be more severe within the ATL group (ATL vs. tsSAHE, integrity of contralateral upper quadrant: 65% vs. 97%, p=.002; OpR tractography damage: 69.2 mm3 vs. 3.8 mm3 , p=.002). Volumetric OpR tractography damage could reliably predict VFD incidence (86% sensitivity, 78% specificity) and could significantly explain VFD extent (R2 =.47, p=.0001). FBA revealed a more widespread decline of fibre cross-section within the ATL group. In the context of controversial visual outcomes following epilepsy surgery, this study provides clinical as well as neuroimaging evidence for a higher risk and greater severity of postoperative VFDs after ATL compared to tsSAHE. Volumetric OpR tractography damage is a feasible parameter to reliably predict this morbidity in both treatment groups and may ultimately support personalized planning of surgical candidates. Advanced diffusion analysis tools such as FBA offer a structural explanation of surgically induced visual pathway damage, allowing noninvasive quantification and visualization of micro- and macrostructural tract affection.

The Determiners of Temporal Lobe Epilepsy Surgery Outcome in a Developing Country

Background: Epilepsy surgery has become a successful treatment option for patients with drug-resistant epilepsies. Objectives: This study aimed to assess temporal lobe epilepsy (TLE) surgery outcome and its association with epilepsy duration, the presence of pre-surgical generalized tonic-clonic seizure (GTCS), and brain MRI findings. Materials &amp; Methods: This retrospective study was performed from 2016 to 2020 at Loghman-Hakim Hospital, Tehran, Iran. The patients’ demographic data, epilepsy type, duration, frequency, brain image findings, the selected surgical approaches, and histopathological findings were collected. The post-operative seizure outcome was expressed one year according to the proposed International League Against Epilepsy (ILAE) classification system. The independent sample t-test, chi-square, and one-way analysis of variance were applied to analyze the differences between variables in terms of quantitative and categorical data. Results: A total number of 69 TLE surgeries were enrolled in our study. No differences were found in the surgical outcome base on the ILAE classification system of patients with lesional vs non-lesional MRIs (P=0.834). In patients with mesial temporal sclerosis, no correlation was found between the surgical approaches including selective amygdalohippocampectomy, anterior temporal lobectomy, and post-operative seizure outcome (P=0.142). Seven patients (10.1%) developed post-operative functional seizures. Conclusion: In our study, the epilepsy duration and the presence of GTCSs before surgery had no effect on the surgery outcome. In patients with mesial temporal sclerosis, amygdalohippocampectomy, and anterior temporal lobectomy did not confer different surgical outcomes. TLE patients with normal MRI showed similar surgical outcomes as lesional patients. A significantly high proportion of our patients developed functional seizures, postoperatively.

Transcortical selective amygdalohippocampectomy for intractable mesial temporal lobe epilepsy: a review of outcomes in a single center

Introduction: Various surgical procedures have been found to effectively treat intractable temporal lobe epilepsy (TLE), including transcortical selective amygdalohippocampectomy (SAH), which is intended to protect the temporal lobe and to prevent interference with vascular structure. This research analyzed the outcome of post-operative seizure-free with transcortical selective amygdalohippocampectomy for intractable mesial temporal lobe epilepsy patients in a minimum two-year follow-up after surgery. Methods: Data of one hundred ninety-two patients who had undergone transcortical selective amygdalohippocampectomy for non-lesional, medically intractable, temporal lobe epilepsy were analyzed. Result: The statistical analysis indicated that Focal to Bilateral Tonic-Clonic Seizure had a more significant outcome (p=0.019) than other seizures. In all research subjects, after three, six, and twelve years of follow-up, the chance for a seizure-free after surgery was respectively 93.2 percent, 67.9 percent, and 36.7 percent with a median average survival period for all subjects of 11.00 years (95 % CI: 8.55 – 13.44) Conclusions: Transcortical selective amygdalohippocampectomy is an effective therapy for intractable mesial temporal lobe epilepsy and provides a satisfactory outcome. The transcortical approach allows an appropriate operative field by careful dissection with limited retraction to eliminate the epileptogenic target while preventing damage to the underlying vascular and cortical structures.