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

BACKGROUND: We 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. METHODS: Clinical 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. RESULTS: At 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). CONCLUSIONS: SAHE 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.

Temporal Lobe Surgery for Epilepsy in a Resource-Limited Vietnamese Cohort.

BACKGROUND: Epilepsy surgery is traditionally difficult to pursue in resource-limited countries but is nevertheless essential in the treatment of medication-refractory, surgically amenable epilepsy. METHODS: With the help of international collaboration, a successful epilepsy program was started in Vietnam. This article comprises a retrospective chart review, combined with prospective longitudinal follow-up of 35 cases of unilateral drug-resistant epilepsy in the temporal lobe who underwent temporal lobectomy, in Viet Duc University Hospital from May 2018 to September 2022. RESULTS: The female/male ratio was 0.6:1, and focal seizures with impaired awareness accounted for 97.14% of patients. Of patients with focal awareness seizures, 51.41% were localized and detected by electroencephalography. Postoperatively, 80% of patients were seizure free (Engel I) at 1 year, and the remaining 20% had worthwhile seizure improvement (Engel II). Postoperative temporal lobe pathology was categorized as follows: mesial temporal sclerosis (48.57%), focal cortical dysplasia (25.71%), and low-grade neoplasms (25.71%). Of patients, 17.14% had postoperative complications (5 infections and 1 transient extremity paresis), and there were no deaths. CONCLUSIONS: Even in low-resource environments, effective and safe surgical care can be provided for drug-resistant epilepsy caused by temporal lobe disease. This study serves as a model of international collaboration and support for future hospitals in low-resource environments to replicate.

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

Epilepsy is a prevalent neurological condition that affects individuals of all ages and genders worldwide. Surgical intervention for drug-resistant epilepsy has been found to improve quality of life, with patient independence being of utmost importance. Methods: 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. Results: 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. Conclusions: 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.

Burr hole microsurgical subtemporal selective amygdalohippocampectomy.

INTRODUCTION: 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. METHODS: 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 14 mm, we used two types of approaches: preauricular, 25 cases, and supra-auricular, 18 cases. The follow-up ranged from 36 to 78 months (median 59 months). One patient died 16 months after surgery (accident). RESULTS: 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. CONCLUSIONS: 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.

Anterior transtemporal endoscopic selective amygdalohippocampectomy: a virtual and cadaveric feasibility study.

PURPOSE: Selective amygdalohippocampectomy (SelAH) is one of the most common surgical treatments for mesial temporal sclerosis. Microsurgical approaches are associated with the risk of cognitive and visual deficits due to damage to the cortex and white matter (WM) pathways. Our objective is to test the feasibility of an endoscopic approach through the anterior middle temporal gyrus (aMTG) to perform a SelAH. METHODS: Virtual simulation with MRI scans of ten patients (20 hemispheres) was used to identify the endoscopic trajectory through the aMTG. A cadaveric study was performed on 22 specimens using a temporal craniotomy. The anterior part of the temporal horn was accessed using a tubular retractor through the aMTG after performing a 1.5 cm corticectomy at 1.5 cm posterior to the temporal pole. Then, an endoscope was introduced. SeIAH was performed in each specimen. The specimens underwent neuronavigation-assisted endoscopic SeIAH to confirm our surgical trajectory. WM dissection using Klingler's technique was performed on five specimens to assess WM integrity. RESULTS: This approach allowed the identification of collateral eminence, lateral ventricular sulcus, choroid plexus, inferior choroidal point, amygdala, hippocampus, and fimbria. SelAH was successfully performed on all specimens, and CT neuronavigation confirmed the planned trajectory. WM dissection confirmed the integrity of language pathways and optic radiations. CONCLUSIONS: Endoscopic SelAH through the aMTG can be successfully performed with a corticectomy of 15 mm, presenting a reduced risk of vascular injury and damage to WM pathways. This could potentially help to reduce cognitive and visual deficits associated with SelAH.

Higher phase-amplitude coupling between ripple and slow oscillations indicates the distribution of epileptogenicity in temporal lobe epilepsy with hippocampal sclerosis.

OBJECTIVE: We assessed the diagnostic utility of the occurrence rate of high-frequency oscillations and modulation index (MI) from intraoperative electrocorticography (ioECoG) in determining the extent of epileptogenicity in mesial temporal lobe epilepsy (TLE) with hippocampal sclerosis (HS). METHODS: We enrolled 17 patients who underwent selective amygdalohippocampectomy (SelAH) for TLE due to HS. We analyzed the occurrence rate of ripples (80-200 Hz) and fast ripples (200-300 Hz); and MI between ripples and 3-4 Hz (MIRipples/3-4 Hz) and fast ripples and 3-4 Hz (MIFRs/3-4 Hz) from the amygdala, hippocampus, and lateral temporal lobe (LTL) pre-SelAH and the LTL post-SelAH, and subsequently categorized the patients into good and poor seizure outcome groups. We compared the occurrence rates and MIs over each region of interest between both groups. Receiver operating characteristic analysis was used to identify the most optimal indicator to predict poor surgical outcomes. RESULTS: In the poor seizure outcome group, an increase in the occurrence rate of ripples was seen in the hippocampus and LTL pre-SelAH and the LTL post-SelAH. The MIRipples/3-4 Hz from the LTL pre-SelAH was the most indicative factor of poor outcome. CONCLUSIONS: High occurrence rate of ripples and MIRipples/3-4 Hz from the LTL showed wide epileptogenicity in TLE patients with poor seizure outcomes after SelAH. Our data suggest that the analysis of the occurrence rate of HFOs and MIHFOs/3-4 Hz from ioECoG, especially from the LTL, can indicate the distribution of epileptogenicity in TLE with HS.

Memory and executive functioning outcomes of selective amygdalohippocampectomy in patients with hippocampal sclerosis: A preliminary study in a developing country.

Background: Selective amygdalohippocampectomy (SA) is an effective treatment for drug-resistant cases of epilepsy due to hippocampal sclerosis (HS). However, its neurocognitive outcomes are inconsistent across the previous studies, pointing to potential location-specific confounders. Here, we investigated the neurocognitive outcomes of SA in an Iranian center recently adopting this approach. Methods: Thirty adults (53.3% of females, age 31.4 ± 6.2 years) with drug-resistant epilepsy due to HS were included in the study. Patients were stratified into surgical (n = 15) and medical (n = 15) treatment groups based on their preferences. Neurocognitive function was assessed before and 6 months after intervention using Wisconsin Card Sorting Test (WCST), Wechsler Adult Intelligence Scale-Revised, and Wechsler Memory Scale- Third Edition (WMS-III). Postintervention performance changes were compared between the two groups, and predictors of worse postoperative outcomes were investigated. Results: Longitudinal changes of performance in WMS-III and WCST were significantly different between the surgically and medically treated patients. Postoperative WMS-III performance showed an average 25% decline (mean ∆T2-T1 = -25.1%, T = -6.6, P < 0.001), and WCST performance improved by an average of 49% (mean ∆T2-T1 = +49.1%, T = 4.6, P < 0.001). The decline in memory performance was more severe in the left-sided surgery and in patients with higher baseline education (mean ∆T2-T1 = -31.1%, T = -8.9, P < 0.001). Conclusion: In our center, executive functioning improved or remained stable after SA, but memory functions declined moderately. The left-sided SA and higher education were associated with more severe decline in memory functions, highlighting the need for special considerations for these groups.

Can intraoperative electrocorticography be used to minimize the extent of resection in patients with temporal lobe epilepsy associated with hippocampal sclerosis?

OBJECTIVE: Tailored surgery to extensively resect epileptogenic lesions using intraoperative electrocorticography (ioECoG) may improve seizure outcomes. However, resection of large areas is associated with decreased memory function postoperatively. The authors assessed whether ioECoG could provide useful information on how to minimize the focus resection and obtain better seizure outcomes without memory deterioration. They examined the postoperative seizure-free period and memory alteration in a retrospective cohort of patients with mesial temporal lobe epilepsy (TLE) due to hippocampal sclerosis (HS) in whom the extent of removal was determined using ioECoG findings. METHODS: The authors enrolled 82 patients with TLE associated with HS who were treated surgically. Transsylvian amygdalohippocampectomy was indicated as the first step. When visual inspection identified interictal epileptic discharges from the lateral temporal lobe on ioECoG, anterior temporal lobectomy (ATL) was eventually performed. The patients were divided into the selective amygdalohippocampectomy (SA, n = 40) and ATL (n = 42) groups. Postoperative seizure outcomes were assessed at 1, 2, 3, 5, and 7 years postoperatively using the International League Against Epilepsy classification. The Kaplan-Meier survival analysis was applied to evaluate the period of seizure recurrence between the SA and ATL groups. Factors attributed to seizure recurrence were analyzed using the Cox proportional hazards model, and they were as follows: epileptic focal laterality; age at seizure onset (< 10 or ≥ 10 years old); seizure frequency (more than weekly or less than weekly seizures); history of focal to bilateral tonic-clonic seizure; infectious etiology; and surgical procedure. The Wechsler Memory Scale-Revised was used to evaluate memory function pre- and postoperatively. RESULTS: Seizure outcomes were significantly worse in the SA group than in the ATL group at 2 years postoperatively (p = 0.045). The International League Against Epilepsy class 1 outcomes at 7 years postoperatively in the SA and ATL groups were 63% and 81%, respectively. Kaplan-Meier analysis showed that seizure recurred significantly earlier in the SA group than in the ATL group (p = 0.031). The 2-way ANOVA analysis was used to compare the SA and ATL groups in each memory category, and revealed that there was no significant difference regardless of the side of surgery. CONCLUSIONS: Visual assessment of ioECoG cannot be used as an indicator to minimize epileptic focus resection in patients with TLE associated with HS. ATL is more effective in obtaining seizure-free outcomes; however, both ATL and SA can preserve memory function.

Experience From 211 Transcortical Selective Amygdalohippocampectomy Procedures: Relevant Surgical Anatomy and Review of the Literature.

BACKGROUND: Selective amygdalohippocampectomy (SelAH) is designed to treat medically refractory mesial temporal lobe epilepsy with reduced morbidity compared to standard anterior temporal lobectomy. At our institution, we perform SelAH via a transcortical approach via small corticectomy in the middle temporal gyrus. OBJECTIVE: To discuss the surgical anatomy and nuances of SelAH, share our institutional experience, and perform a review of literature. METHODS: Institutional experience was recorded by collecting demographic and outcome data from 1999 to 2017 under an Institutional Review Board protocol in a prospective manner using a REDCap database. RESULTS: A total of 211 SelAH procedures were performed at our institution between 1999 and 2017. Of these patients, 54% (113/211) were females. The average age at surgery was 39.4 yr. Two-year Engel outcome data were available for 168 patients, of which 73% (123/168) had Engel I outcomes. Engel II outcomes were reported in 16.6% (28/168), III in 4.7% (8/168), and IV in 5.3% (9/168). Our review of literature showed that this is comparable to the seizure freedom rates reported by other groups. We then reviewed our surgical methodology based on operative reports and created illustrations of the surgical anatomy of temporal lobe approach. These illustrations were compared with postoperative magnetic resonance imaging to provide a better 3D understanding of the complex architecture of mesial temporal structures. CONCLUSION: SelAH is a minimally invasive, safe, and effective approach for the treatment of medically refractory epilepsy with good surgical outcomes and low morbidity. We feel that mastering the complex anatomy of this approach helps achieve successful outcomes.

Endoscopic Transcortical Selective Amygdalohippocampectomy for Mesial Temporal Lobe Epilepsy: 2-Dimensional Operative Video.

This surgical video shows a 19-yr-old woman with focal impaired awareness seizures. Seizure semiology showed no lateralizing signs. Ictal electroencephalography (EEG) failed to determine the seizure origin. Interictal EEG showed bilateral spike-and-waves at the temporal electrodes. Magnetic resonance imaging (MRI) showed suspected hippocampal sclerosis on the right side. To determine the side of the focus, depth electrodes were implanted in both hippocampi. Invasive video EEG identified the seizure origin on the right. The decision was made to perform selective amygdalohippocampectomy (SelAH) via the middle temporal gyrus (MTG). An endoscope was used to minimize the craniotomy and shorten the skin incision. A 5-cm linear skin incision and 2.5-cm craniotomy were made. A thin tube was inserted to the inferior horn of the lateral ventricle (Inf-H) under neuronavigation to guide the route to the Inf-H. The endoscope was introduced. A 1.5-cm corticotomy was made at the MTG, and white matter was aspirated until opening the Inf-H. The hippocampus and parahippocampal gyrus were removed with the usual steps in microsurgical SelAH. The surgical time was 4 h 20 min. The patient was discharged without complications and has remained seizure free. In addition to the preoperative objectives, using an endoscope widens the surgical view in the Inf-H compared with microsurgical procedures. Although seizure and cognitive outcomes are expected to be comparable to those from other methods of SelAH, invasiveness might be reduced. This appears to represent the first video report of endoscopic SelAH. The patient consented to the procedure and publication of her images and surgical video.

Surgical Outcomes and EEG Prognostic Factors After Stereotactic Laser Amygdalohippocampectomy for Mesial Temporal Lobe Epilepsy.

Objective: To assess the seizure outcomes of stereotactic laser amygdalohippocampectomy (SLAH) in consecutive patients with mesial temporal lobe epilepsy (mTLE) in a single center and identify scalp EEG and imaging factors in the presurgical evaluation that correlate with post-surgical seizure recurrence. Methods: We retrospectively reviewed the medical and EEG records of 30 patients with drug-resistant mTLE who underwent SLAH and had at least 1 year of follow-up. Surgical outcomes were classified using the Engel scale. Univariate hazard ratios were used to evaluate the risk factors associated with seizure recurrence after SLAH. Results: The overall Engel class I outcome after SLAH was 13/30 (43%), with a mean postoperative follow-up of 48.9 ± 17.6 months. Scalp EEG findings of interictal regional slow activity (IRSA) on the side of surgery (HR = 4.05, p = 0.005) and non-lateralizing or contra-lateralizing seizure onset (HR = 4.31, p = 0.006) were negatively correlated with postsurgical seizure freedom. Scalp EEG with either one of the above features strongly predicted seizure recurrence after surgery (HR = 7.13, p < 0.001) with 100% sensitivity and 71% specificity. Significance: Understanding the factors associated with good or poor surgical outcomes can help choose the best candidates for SLAH. Of the variables assessed, scalp EEG findings were the most clearly associated with seizure outcomes after SLAH.

Initial delta and delayed theta/alpha pattern in the temporal region on ictal EEG suggests purely hippocampal epileptogenicity in patients with mesial temporal lobe epilepsy.

OBJECTIVE: To determine whether the ictal scalp EEG findings suggest purely hippocampal epileptogenicity in patients with mesial temporal lobe epilepsy (mTLE) associated with hippocampal sclerosis (HS). METHODS: Twenty-three patients with mTLE with pathologically confirmed HS were divided into 12 with epileptogenicity only in the hippocampus (HS only group) and 11 with epileptogenicity in both the hippocampus and temporal neocortex or other locations (HS plus group), based on the combination of surgical procedures, postoperative outcome, and pathological findings. Sixteen underwent selective amygdalohippocampectomy (SelAH) and 7 received anterior temporal lobectomy. Ictal scalp EEG findings of 79 focal impaired awareness seizures were compared between the HS only and HS plus groups. We focused on the 1-4 Hz rhythmic delta activity at ictal onset followed by 5-9 Hz rhythmic theta/alpha activity 10-30 s after the onset in the temporal region. RESULTS: The initial delta and delayed theta/alpha (ID-DT) pattern was observed in 8 of 12 patients in the HS only group, but in none of 11 patients in the HS plus group (p < 0.01). CONCLUSIONS: ID-DT pattern on ictal EEG suggests purely hippocampal epileptogenicity in mTLE with HS. SIGNIFICANCE: Patients with the ID-DT pattern are likely to become seizure-free after SelAH.

Gray Matter Atrophy: The Impacts of Resective Surgery and Vagus Nerve Stimulation in Drug-Resistant Epilepsy.

BACKGROUND: There is great concern for cognitive function after resective temporal lobe surgery for drug-resistant epilepsy. However, few studies have investigated postoperative anatomical changes, and the downstream effects of surgery are poorly understood. This study investigated volumetric changes after resective surgery and vagus nerve stimulation (VNS) for epilepsy. METHODS: Preoperative and latest postoperative (mean, 28 months) structural T1 magnetic resonance imaging scans were retrospectively obtained for 43 patients: 27 temporal lobe resections (TLRs), 6 extratemporal lobe resections, and 10 VNS, undergoing surgery for drug-resistant epilepsy between 2012 and 2017. Automated volumetric analyses of predefined cortical gray matter and subcortical structures were performed. Preoperative and postoperative volumes were compared, and the effects of age, gender, operation type, resection laterality, selectivity, time since surgery, and seizure outcome on volumetric changes were analyzed. RESULTS: After TLRs, there were reductions in contralateral hemispheric gray matter, temporal lobe, entorhinal cortex, parahippocampal, superior temporal, middle temporal, inferior temporal (P = 0.02), lingual, fusiform, precentral, paracentral, postcentral, pericalcarine gyri, and ipsilateral superior parietal gyrus. After VNS, there was bilateral atrophy in the thalamus, putamen, cerebellum, rostral anterior cingulate, posterior cingulate, medial orbitofrontal, paracentral, fusiform, and transverse temporal gyri. There was a significant effect of surgery type but no effect of age, gender, operation type, resection laterality, selectivity, time since surgery, and seizure outcome on contralateral hippocampal gray matter change. CONCLUSION: This is the first study to demonstrate volumetric decreases in temporal and connected regions after TLRs and VNS. These results provide interesting insight into functional network changes.

Assessing the connectional anatomy of superior and lateral surgical approaches for medial temporal lobe epilepsy.

The most common approaches in the treatment of epilepsy, the trans-sylvian selective amygdalohippocampectomy (SAH) and the anterior temporal lobe resection (ATLR) reach the medial temporal lobe through different surgical routes. Our aim was to delineate the white matter (WM) fiber tracts at risk in relation to trans-sylvian SAH and ATLR by defining each fascicle en route to medial temporal lobe during each approach. ATLR and trans-sylvian SAH were performedand related WM tracts en route to medial temporal region were presented in relation to the relevant approaches and surrounding neurovascular structures. The WM tracts most likely to be disrupted during trans-sylvian SAH along the roof of the temporal horn were the UF - and less commonly IFOF - at the layer of the external capsule, anterior commissure, anterior bend of optic radiations, and sublenticular internal capsule. Amygdaloid projections to the claustrum, putamen and globus pallidus, the tail of caudate and the peduncle of the lentiform nucleus were also in close proximity to the resection cavity. Fiber tracts most likely to be impaired during ATLR included the UF, ILF, IFOF, anterior commissure, optic radiations, and, less likely, the vertical ventral segment of the arcuate fascicle. Both ATLR and trans-sylvian SAH carry the risk of injury to WM pathways, which may result in unpredictable functional loss. A detailed 3-D knowledge of the related connectional anatomy will help subside neurocognitive, neuroophtalmologic, neurolinguistic complications of epilepsy surgery, providing an opportunity to tailor the surgery according to patient's unique connectional and functional anatomy.

Comparison of the keyhole trans-middle temporal gyrus approach and transsylvian approach for selective amygdalohippocampectomy: A single-center experience.

Several approach routes exist for selective amygdalohippocampectomy (SAH); however, previous reports regarding a comparison of these routes are limited. Here, we compared trans-middle temporal gyrus (T2) SAH and transsylvian (TS) SAH in terms of seizure outcome, visual-field defect, memory function, and operation time in our institution. This retrospective study examined the data of 16 patients with medically intractable mesial temporal lobe epilepsy. Six patients underwent trans-T2 SAH and 10 patients underwent TS SAH between July 2014 and February 2019 in Osaka City University Hospital. In trans-T2 SAH, we performed a keyhole temporal craniotomy and a small corticotomy on T2. In TS SAH, we performed a 1.5 cm corticotomy along the inferior periinsular sulcus after opening the sylvian fissure. Amygdalohippocampectomy after reaching the inferior horn of the lateral ventricle was performed in the same manner in both procedures. The seizure outcome, visual-field defect, memory function, and operation time were retrospectively compared between the procedures. Seizure-free outcomes were achieved for six patients in the trans-T2 SAH and eight patients in the TS SAH group. There were no significant differences in the seizure outcome, visual-field defect, and memory function. The operation time was significantly shorter for trans-T2 SAH than TS SAH. The postoperative scar was less conspicuous for trans-T2 SAH. Trans-T2 SAH and TS SAH were comparable in terms of the seizure outcome, visual-field defect, and memory function. The operation time and length of the skin incision were shorter for trans-T2 SAH, suggesting that it may be preferable for general epilepsy surgeons.

Subtemporal selective amygdalohippocampectomy in patients with mesial temporal lobe epilepsy: Systematic review of seizure and neuropsychological outcomes.

In addition to standard anterior temporal lobectomy (ATL), subtemporal selective amygdalohippocampectomy (sSAH) is also a common technique for the treatment of medically intractable mesial temporal lobe epilepsy (MTLE). We conducted a systematic literature review to determine the seizure and neuropsychological outcomes in patients with MTLE who underwent sSAH. We searched PubMed and Embase using Medical Subject Headings and keywords related to sSAH, seizure outcome, and neuropsychological outcome. Titles, abstracts, and full-texts were screened in light of inclusion and exclusion criteria that were established a priori. Potential papers were reviewed by 3 reviewers, who reached a consensus on the final papers to be included. Literature review identified 208 abstracts from which a total of 29 full-text articles were reviewed. Six studies containing data from 4 countries (3 continents) met our inclusion criteria. The seizure-free rates at 12 months after sSAH ranged from 59.1% to 61.5% in 4 studies. Four studies showed that seizure-free rates ranged from 56% to 82.6% at 24 months after surgery. Six studies evaluated the neuropsychological changes of patients with MTLE after sSAH, including intelligence, verbal memory, nonverbal memory, language function, and so on. In terms of neuropsychological outcomes, there are some differences among the 6 studies. Taken together, sSAH can provide a considerable rate of seizure freedom. In addition, the neuropsychological outcomes of patients who underwent sSAH were slightly different among 6 studies. Therefore, large-scale case series or randomized controlled trials (RCTs) are needed to clarify the advantages and disadvantages of the sSAH.

Seizure and neuropsychological outcomes in a large series of selective amygdalohippocampectomies with a minimally invasive subtemporal approach.

OBJECTIVE: Debate continues over proper surgical treatment for mesial temporal lobe epilepsy (MTLE). Few large comprehensive studies exist that have examined outcomes for the subtemporal selective amygdalohippocampectomy (sSAH) approach. This study describes a minimally invasive technique for sSAH and examines seizure and neuropsychological outcomes in a large series of patients who underwent sSAH for MTLE. METHODS: Data for 152 patients (94 women, 61.8%; 58 men, 38.2%) who underwent sSAH performed by a single surgeon were retrospectively reviewed. The sSAH technique involves a small, minimally invasive opening and preserves the anterolateral temporal lobe and the temporal stem. RESULTS: All patients in the study had at least 1 year of follow-up (mean [SD] 4.52 [2.57] years), of whom 57.9% (88/152) had Engel class I seizure outcomes. Of the patients with at least 2 years of follow-up (mean [SD] 5.2 [2.36] years), 56.5% (70/124) had Engel class I seizure outcomes. Preoperative and postoperative neuropsychological test results indicated no significant change in intelligence, verbal comprehension, perceptual reasoning, attention and processing, cognitive flexibility, visuospatial memory, or mood. There was a significant change in word retrieval regardless of the side of surgery and a significant change in verbal memory in patients who underwent dominant-side resection (p < 0.05). Complication rates were low, with a 1.3% (2/152) permanent morbidity rate and 0.0% mortality rate. CONCLUSIONS: This study reports a large series of patients who have undergone sSAH, with a comprehensive presentation of a minimally invasive technique. The sSAH approach described in this study appears to be a safe, effective, minimally invasive technique for the treatment of MTLE.

Safety of the paramedian supracerebellar-transtentorial approach for selective amygdalohippocampectomy.

OBJECTIVE: The goal of this study was to assess the reproducibility and safety of the recently introduced paramedian supracerebellar-transtentorial (PST) approach for selective amygdalohippocampectomy (SA). METHODS: The authors performed a retrospective analysis of prospectively collected data originating from their surgical register of patients undergoing SA via a PST approach for lesional medial temporal lobe epilepsy. All patients received thorough pre- and postoperative clinical (neurological, neuropsychological, psychiatric) and instrumental (ictal and long-term EEG, invasive EEG if needed, MRI) workup. Surgery-induced complications were assessed at discharge and at every follow-up thereafter and were classified according to Clavien-Dindo grade (CDG). Epilepsy outcome was defined according to Engel classification. Data were reported according to common descriptive statistical methods. RESULTS: Between May 2015 and May 2018, 17 patients underwent SA via a PST approach at the authors' institution (hippocampal sclerosis in 13 cases, WHO grade II glioma in 2 cases, and reactive gliosis in 2 cases). The median postoperative follow-up was 7 months (mean 9 months, range 3-19 months). There was no surgery-related mortality and no complication (CDG ≥ 2) in the whole series. Transitory CDG 1 surgical complications occurred in 4 patients and had resolved in all of them by the first postoperative follow-up. One patient showed a deterioration of neuropsychological performance with new slight mnestic deficits. No patient experienced a clinically relevant postoperative visual field defect. No morbidity due to semisitting position was recorded. At last follow-up 13/17 (76.4%) patients were in Engel class I (9/17 [52.9%] were in class IA). CONCLUSIONS: The PST approach is a reproducible and safe surgical route for SA. The achievable complication rate is in line with the best results in the literature. Visual function outcome particularly benefits from this highly selective, neocortex-sparing approach. A larger patient sample and longer follow-up will show in the future if the seizure control rate and neuropsychological outcome also compare better than those achieved with current common surgical techniques.

Temporal lobe structural evaluation after transsylvian selective amygdalohippocampectomy.

OBJECTIVE: Mesial temporal lobe epilepsy (MTLE) is the most common type of focal epilepsy in adolescents and adults, and in 65% of cases, it is related to hippocampal sclerosis (HS). Selective surgical approaches to the treatment of MTLE have as their main goal resection of the amygdala and hippocampus with minimal damage to the neocortex, temporal stem, and optic radiations (ORs). The object of this study was to evaluate late postoperative imaging findings on the temporal lobe from a structural point of view. METHODS: The authors conducted a retrospective evaluation of all patients with refractory MTLE who had undergone transsylvian selective amygdalohippocampectomy (SAH) in the period from 2002 to 2015. A surgical group was compared to a control group (i.e., adults with refractory MTLE with an indication for surgical treatment of epilepsy but who did not undergo the surgical procedure). The inferior frontooccipital fasciculus (IFOF), uncinate fasciculus (UF), and ORs were evaluated on diffusion tensor imaging analysis. The temporal pole neocortex was evaluated using T2 relaxometry. RESULTS: For the IFOF and UF, there was a decrease in anisotropy, voxels, and fibers in the surgical group compared with those in the control group (p < 0.001). An increase in relaxometry time in the surgical group compared to that in the control group (p < 0.001) was documented, suggesting gliosis and neuronal loss in the temporal pole. CONCLUSIONS: SAH techniques do not seem to totally preserve the temporal stem or even spare the neocortex of the temporal pole. Therefore, although the transsylvian approaches have been considered to be anatomically selective, there is evidence that the temporal pole neocortex suffers structural damage and potentially functional damage with these approaches.

Selective posterior cerebral artery amobarbital test: a predictor of memory following subtemporal selective amygdalohippocampectomy.

BACKGROUND: The selective posterior cerebral artery (PCA) amobarbital test, or PCA Wada test, is used to predict memory impairment after epilepsy surgery in patients who have previously had a failed internal carotid artery (ICA) amobarbital test. METHODS: Medical records from 2012 to 2018 were retrospectively reviewed for all patients with seizures who underwent a selective PCA Wada test at our institution following a failed or inconclusive ICA Wada test. Standardized neuropsychological testing was performed before and during the Wada procedure and postoperatively in patients who underwent resection. RESULTS: Thirty-three patients underwent a selective PCA Wada test, with no complications. Twenty-six patients with medically refractory epilepsy had a seizure focus amenable to selective amygdalohippocampectomy (AHE). Six patients (23%, n=26) had a failed PCA Wada test and did not undergo selective AHE, seven (27%) declined surgical resection, leaving 13 patients who underwent subtemporal selective AHE. Hippocampal sclerosis was found in all 13 patients (100%). Twelve patients (92%) subsequently underwent formal neuropsychological testing and all were found to have stable memory. Ten patients (77%) were seizure-free (Engel Class I), with average follow-up of 13 months. CONCLUSION: The selective PCA Wada test is predictive of memory outcomes after subtemporal selective AHE in patients with a failed or inconclusive ICA Wada test. Furthermore, given the low risk of complications and potential benefit of seizure freedom, a selective PCA Wada test may be warranted in patients with medically intractable epilepsy who are candidates for a selective AHE and who have a prior failed or inconclusive ICA Wada test.