The seizure outcome after amygdalohippocampectomy and temporal lobectomy

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

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.

CONCLUSION

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.

Surgery procedures in temporal lobe epilepsies

Temporal lobe epilepsy (TLE) is the most common cause of refractory epilepsy amenable for surgical treatment and seizure control. Surgery for TLE is a safe and effective strategy. The seizure-free rate after surgical resection in patients with mesial or neocortical TLE is about 70%. Resective surgery has an advantage over stereotactic radiosurgery in terms of seizure outcomes for mesial TLE patients. Both techniques have similar results for safety, cognitive outcomes, and associated costs. Stereotactic radiosurgery should therefore be seen as an alternative to open surgery for patients with contraindications for or with reluctance to undergo open surgery. Laser interstitial thermal therapy (LITT) has also shown promising results as a curative technique in mesial TLE but needs to be more deeply evaluated. Brain-responsive stimulation represents a palliative treatment option for patients with unilateral or bilateral MTLE who are not candidates for temporal lobectomy or who have failed a prior mesial temporal lobe resection. Overall, despite the expansion of innovative techniques in recent years, resective surgery remains the reference treatment for TLE and should be proposed as the first-line surgical modality. In the future, ultrasound therapies could become a credible therapeutic option for refractory TLE patients.

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.

Total and partial posterior quadrant disconnection for medically refractory epilepsy: A systematic review

PURPOSE

Posterior quadrant disconnection (PQD) is a surgical procedure for medically refractory epilepsy (MRE) involving diffuse regions of the temporo-parieto-occipital lobes. We sought to compare factors and efficacy according to PQD extent.

METHODS

We performed a systematic review of the literature reporting the use of PQD since 2004. We analyzed various characteristics of pooled cases, including the role of preoperative studies in patient selection, intraoperative techniques, and outcomes.

RESULTS

Our review of 137 patients from nine studies revealed 66% undergoing total PQD and 34% undergoing partial PQD. Interictal electroencephalography (EEG) findings were predominantly characterized as lateralized for total PQD (56%) and localized within the ipsilateral posterior quadrant in patients undergoing partial PQD (53%). Metabolic functional studies [positron emission tomography (PET) or ictal single-photon emission computed tomography (SPECT)] played a role in surgical decision-making in 42% of patients who underwent total PQD. Wada and/or functional magnetic resonance imaging (fMRI) was more often utilized for partial PQD (22%) than total PQD (3%) as was intracranial electroencephalography (icEEG) (30% versus 13%, respectively). Overall, 75% of total PQD patients achieved seizure freedom [defined as Engel I or International League Against Epilepsy (ILAE) Class 1 outcome] in comparison to 63% of partial PQD patients (p = .078). New visual field deficits were seen in 12% and new or worsened hemiparesis in 6%. For patients in either cohort, concordance of interictal and ictal EEG findings was found to be predictive of seizure freedom (p = .048).

CONCLUSION

Both total and partial PQD represent effective alternatives for managing patients with MRE whose seizure onset zone (SOZ) involves a diffuse region within the posterior quadrant. While PET and/or SPECT frequently aided in the decision to proceed with total PQD, patients who underwent a tailored, partial multilobar resection were more likely to undergo Wada and/or fMRI testing as well as stage I icEEG studies.

Comparison of minimally invasive and traditional surgical approaches for refractory mesial temporal lobe epilepsy: A systematic review and meta-analysis of outcomes

Magnetic resonance-guided laser interstitial laser therapy (MRgLITT) and radiofrequency ablation (RFA) represent two minimally invasive methods for the treatment of drug-refractory mesial temporal lobe epilepsy (mTLE). We performed a systematic review and a meta-analysis to compare outcomes and complications between MRgLITT, RFA, and conventional surgical approaches to the temporal lobe (i.e., anterior temporal lobe resection [ATL] or selective amygdalohippocampectomy [sAHE]). Forty-three studies (13 MRgLITT, 6 RFA, and 24 surgery studies) involved 554, 123, 1504, and 1326 patients treated by MRgLITT, RFA, ATL, or sAHE, respectively. Engel Class I (Engel-I) outcomes were achieved after MRgLITT in 57% (315/554, range = 33.3%-67.4%), RFA in 44% (54/123, range = 0%-67.2%), ATL in 69% (1032/1504, range = 40%-92.9%), and sAHE in 66% (887/1326, range = 21.4%-93.3%). Meta-analysis revealed no significant difference in seizure outcome between MRgLITT and RFA (Q = 2.74, p = .098), whereas ATL and sAHE were both superior to MRgLITT (ATL: Q = 8.92, p = .002; sAHE: Q = 4.33, p = .037) and RFA (ATL: Q = 6.42, p = .0113; sAHE: Q = 5.04, p = .0247), with better outcome in patients at follow-up of 60 months or more. Mesial hippocampal sclerosis (mTLE + hippocampal sclerosis) was associated with significantly better outcome after MRgLITT (Engel-I outcome in 64%; Q = 8.55, p = .0035). The rate of major complications was 3.8% for MRgLITT, 3.7% for RFA, 10.9% for ATL, and 7.4% for sAHE; the differences did not show statistical significance. Neuropsychological deficits occurred after all procedures, with left-sided surgeries having a higher rate of verbal memory impairment. Lateral functions such as naming or object recognition may be more preserved in MRgLITT. Thermal therapies are effective techniques but show a significantly lower rate of Engel-I outcome in comparison to ATL and sAHE. Between MRgLITT and RFA there were no significant differences in Engel-I outcome, whereby the success of treatment seems to depend on the approach used (e.g., occipital approach). MRgLITT shows a similar rate of complications compared to RFA, whereas patients undergoing MRgLITT may experience fewer major complications compared to ATL or sAHE and might have a more beneficial neuropsychological outcome.

Seizure outcome in temporal glioblastoma surgery: lobectomy as a supratotal resection regime outclasses conventional gross-total resection

Introduction

The postoperative seizure freedom represents an important secondary outcome measure in glioblastoma surgery. Recently, supra-total glioblastoma resection in terms of anterior temporal lobectomy (ATL) has gained growing attention with regard to superior long-term disease control for temporal-located glioblastoma compared to conventional gross-total resections (GTR). However, the impact of ATL on seizure outcome in these patients is unknown. We therefore analyzed ATL and GTR as differing extents of resection in regard of postoperative seizure control in patients with temporal glioblastoma and preoperative symptomatic seizures.

Methods

Between 2012 and 2018, 33 patients with preoperative seizures underwent GTR or ATL for temporal glioblastoma at the authors’ institution. Seizure outcome was assessed postoperatively and 6 months after tumor resection according to the International League Against Epilepsy (ILAE) classification and stratified into favorable (ILAE class 1) versus unfavorable (ILAE class 2–6).

Results

Overall, 23 out of 33 patients (70%) with preoperative seizures achieved favorable seizure outcome following resection of temporal located glioblastoma. For the ATL group, postoperative seizure freedom was present in 13 out of 13 patients (100%). In comparison, respective rates for the GTR group were 10 out of 20 patients (50%) (p = 0.002; OR 27; 95% CI 1.4–515.9).

Conclusions

ATL in terms of a supra-total resection strategy was associated with superior favorable seizure outcome following temporal glioblastoma resection compared to GTR. Regarding above mentioned survival benefit following ATL compared to GTR, ATL as an aggressive supra-total resection regime might constitute the surgical modality of choice for temporal-located glioblastoma.

Partial cortico-hippocampectomy in cats, as therapy for refractory temporal epilepsy: A descriptive cadaveric study

Cats, similar to humans, are known to be affected by hippocampal sclerosis (HS), potentially causing antiepileptic drug (AED) resistance. HS can occur as a consequence of chronic seizure activity, trauma, inflammation, or even as a primary disease. In humans, temporal lobe resection is the standardized therapy in patients with refractory temporal lobe epilepsy (TLE). The majority of TLE patients are seizure free after surgery. Therefore, the purpose of this prospective cadaveric study is to establish a surgical technique for hippocampal resection in cats as a treatment for AED resistant seizures. Ten cats of different head morphology were examined. Pre-surgical magnetic resonance imaging (MRI) and computed tomography (CT) studies of the animals’ head were carried out to complete 3D reconstruction of the head, brain, and hippocampus. The resected hippocampal specimens and the brains were histologically examined for tissue injury adjacent to the hippocampus. The feasibility of the procedure, as well as the usability of the removed specimen for histopathological examination, was assessed. Moreover, a micro-CT (mCT) examination of the brain of two additional cats was performed in order to assess temporal vasculature as a reason for possible intraoperative complications. In all cats but one, the resection of the temporal cortex and the hippocampus were successful without any evidence of traumatic or vascular lesions in the surrounding neurovascular structures. In one cat, the presence of mechanical damage (a fissure) of the thalamic surface was evident in the histopathologic examination of the brain post-resection. All hippocampal fields and the dentate gyrus were identified in the majority of the cats via histological examination. The study describes a new surgical approach (partial temporal cortico-hippocampectomy) offering a potential treatment for cats with clinical and diagnostic evidence of temporal epilepsy which do not respond adequately to the medical therapy.

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.

Surgical outcomes for medically intractable epilepsy in low- and middle-income countries: a systematic review and meta-analysis

OBJECTIVE

The aim of this study was to describe the current state of epilepsy surgery and establish estimates of seizure outcomes following surgery for medically intractable epilepsy (MIE) in low- and middle-income countries (LMICs).

METHODS

The MEDLINE and Embase databases were searched without publication date restriction. This search was supplemented by a manual screen of key epilepsy and neurosurgical journals (January 2005 to December 2016). Studies that reported outcomes for at least 10 patients of any age undergoing surgery for MIE in LMICs over a defined follow-up period were included. A meta-analysis with a random-effects model was performed in accordance with the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) statement and MOOSE (Meta-analysis of Observational Studies in Epidemiology) guidelines. Pooled estimates of seizure freedom and favorable seizure outcomes following anterior temporal lobectomy with or without amygdalohippocampectomy (ATL ± AH) were reported.

RESULTS

Twenty studies were selected, of which 16 were from Asian centers. The average age at surgery in all studies was less than 30 years, and the average preoperative duration of epilepsy ranged from 3 to 16.1 years. Mesial temporal sclerosis accounted for 437 of 951 described pathologies, and 1294 of the 1773 procedures were ATL ± AH. Based on 7 studies (646 patients) the pooled seizure freedom estimate following ATL ± AH was 68% (95% CI 55%-82%). Based on 8 studies (1096 patients), the pooled estimate for favorable seizure outcomes was 79% (95% CI 74%-85%).

CONCLUSIONS

Surgery for MIE in LMICs shows a high percentage of seizure freedom and favorable outcomes. These findings call for a concerted global effort to improve timely access to surgery for MIE patients in these regions, including investments aimed at refining existing and establishing additional centers.

Systematic review and network meta-analysis of resective surgery for mesial temporal lobe epilepsy

OBJECTIVE

To evaluate the effectiveness of anterior temporal lobectomy (ATL) versus selective amygdalohippocampectomy (SAH) on seizure-free outcome in patients with temporal lobe epilepsy, using both direct and indirect evidence from the literature.

METHODS

MEDLINE, Embase and Cochrane databases were searched for original research articles and systematic reviews comparing ATL versus SAH, and ATL or SAH versus medical management (MM). The outcome was seizure freedom at 12 months of follow-up or longer. Direct pairwise meta-analyses were conducted, followed by a random-effect Bayesian network meta-analysis (NMA) combining direct and indirect evidence.

RESULTS

Twenty-eight articles were included (18 compared ATL vs SAH, 1 compared ATL vs SAH vs MM, 8 compared ATL vs MM, and 1 compared SAH vs MM). Direct pairwise meta-analyses showed no significant differences in seizure-free outcome of ATL versus SAH (OR 1.14, 95% CI 0.93 to 1.39; p=0.201), but the odds of seizure-free outcome were higher for ATL versus MM (OR 29.16, 95% CI 10.44 to 81.50; p<0.00001), and SAH versus MM (OR 28.42, 95% CI 10.17 to 79.39; p<0.00001). NMA also showed that the odds of seizure-free outcome were no different in ATL versus SAH (OR 1.15, 95% credible interval (CrI) 0.84-1.15), but higher for ATL versus MM (OR 27.22, 95% CrI 15.38-27.22), and SAH versus MM (OR 23.57, 95% CrI 12.67-23.57). There were no significant differences between direct and indirect comparisons (all p>0.05).

CONCLUSION

Direct evidence, indirect evidence and NMA did not identify a difference in seizure-free outcome of ATL versus SAH.

Surgical Considerations of Intractable Mesial Temporal Lobe Epilepsy

Surgery of temporal lobe epilepsy is the best opportunity for seizure freedom in medically intractable patients. The surgical approach has evolved to recognize the paramount importance of the mesial temporal structures in the majority of patients with temporal lobe epilepsy who have a seizure origin in the mesial temporal structures. For those individuals with medically intractable mesial temporal lobe epilepsy, a selective amygdalohippocampectomy surgery can be done that provides an excellent opportunity for seizure freedom and limits the resection to temporal lobe structures primarily involved in seizure genesis.

Role of the temporal pole in temporal lobe epilepsy seizure networks: an intracranial electrode investigation

OBJECTIVE A convergence of clinical research suggests that the temporal pole (TP) plays an important and potentially underappreciated role in the genesis and propagation of seizures in temporal lobe epilepsy (TLE). Understanding its role is becoming increasingly important because selective resections for medically intractable TLE spare temporopolar cortex (TPC). The purpose of this study was to characterize the role of the TPC in TLE after using dense electrocorticography (ECoG) recordings in patients undergoing invasive monitoring for medically intractable TLE. METHODS Chronic ECoG recordings were obtained in 10 consecutive patients by using an array customized to provide dense coverage of the TP as part of invasive monitoring to localize the epileptogenic zone. All patients would eventually undergo cortico-amygdalohippocampectomy. A retrospective review of the patient clinical records including ECoG recordings, neuroimaging studies, neuropathology reports, and clinical outcomes was performed. RESULTS In 7 patients (70%), the TP was involved at seizure onset; in 7 patients (70%), there were interictal discharges from the TP; and in 1 case, there was early spread to the TP. Seizure onset in the TP did not necessarily correlate with preoperative neuroimaging abnormalities of the TP. CONCLUSIONS These data demonstrate that TPC commonly plays a crucial role in temporal lobe seizure networks. Seizure onset from the TP would not have been predicted based on available neuroimaging data or interictal discharges. These findings illustrate the importance of thoroughly considering the role of the TP prior to resective surgery for TLE, particularly when selective mesial resection is being considered.

Mesial temporal lobe epilepsy: long-term seizure outcome of patients primarily treated with transsylvian selective amygdalohippocampectomy

OBJECTIVE The aim of this study was to present long-term seizure outcome data in a consecutive series of patients with refractory mesial temporal lobe epilepsy primarily treated with transsylvian selective amygdalohippocampectomy (SAHE). METHODS The authors retrospectively analyzed prospectively collected data for all patients who had undergone resective surgery for medically refractory epilepsy at their institution between July 1994 and December 2014. Seizure outcome was assessed according to the International League Against Epilepsy (ILAE) and the Engel classifications. RESULTS The authors performed an SAHE in 158 patients (78 males, 80 females; 73 right side, 85 left side) with a mean age of 37.1 ± 10.0 years at surgery. Four patients lost to follow-up and 1 patient who committed suicide were excluded from analysis. The mean follow-up period was 9.7 years. At the last available follow-up (or before reoperation), 68 patients (44.4%) had achieved an outcome classified as ILAE Class 1a, 46 patients (30.1%) Class 1, 6 patients (3.9%) Class 2, 16 patients (10.4%) Class 3, 15 patients (9.8%) Class 4, and 2 patients (1.3%) Class 5. These outcomes correspond to Engel Class I in 78.4% of the patients, Engel Class II in 10.5%, Engel Class III in 8.5%, and Engel Class IV in 2.0%. Eleven patients underwent a second surgery (anterior temporal lobectomy) after a mean of 4.4 years from the SAHE (left side in 6 patients, right side in 5). Eight (72.7%) of these 11 patients achieved seizure freedom. The overall ILEA seizure outcome since (re)operation after a mean follow-up of 10.0 years was Class 1a in 72 patients (47.0%), Class 1 in 50 patients (32.6%), Class 2 in 7 patients (4.6%), Class 3 in 15 patients (9.8%), Class 4 in 8 patients (5.2%), and Class 5 in 1 patient (0.6%). These outcomes correspond to an Engel Class I outcome in 84.3% of the patients. CONCLUSIONS A satisfactory long-term seizure outcome following transsylvian SAHE was demonstrated in a selected group of patients with refractory temporal lobe epilepsy.

Surgical Treatment of Mesiotemporal Lobe Epilepsy: Which Approach is Favorable?

BACKGROUND

Mesiotemporal lobe epilepsy is one of the most frequent causes for pharmacoresistant epilepsy. Different surgical approaches to the mesiotemporal area are used.

OBJECTIVE

To analyze epileptological and neuropsychological results as well as complications of different surgical strategies.

METHODS

This retrospective study is based on a consecutive series of 458 patients all harboring pharmacoresistant mesiotemporal lobe epilepsy. Following procedures were performed: standard anterior temporal lobectomy, anterior temporal or key-hole resection, extended lesionectomy, and transsylvian and subtemporal selective amygdalohippocampectomy. Postoperative outcome was evaluated according to different surgical procedures.

RESULTS

Overall, 1 yr after surgery 315 of 432 patients (72.9%) were classified Engel I; in particular, 72.8% were seizure-free after anterior temporal lobectomy, 76.9% after key-hole resection, 84.4% after extended lesionectomy, 70.3% after transylvian selective amygdalohippocampectomy, and 59.1% after subtemporal selective amygdalohippocampectomy. No significant differences in seizure outcome were found between different resective procedures, neither in short-term nor long-term follow-up. There was no perioperative mortality. Permanent morbidity was encountered in 4.4%. There were no significant differences in complications between different resection types. In the majority of patients, selective attention improved following surgery. Patients after left-sided operations performed significantly worse regarding verbal memory as compared to right-sided procedures. However, surgical approach had no significant effect on memory outcome.

CONCLUSION

Different surgical approaches for mesiotemporal epilepsy analyzed resulted in similar epileptological, neuropsychological results, and complication rates. Therefore, the approach for the individual patient does not only depend on the specific localization of the epileptogenic area, but also on the experience of the surgeon.

Anterior temporal lobectomy versus selective amygdalohippocampectomy in patients with mesial temporal lobe epilepsy

ABSTRACT Objective To contribute our experience with surgical treatment of patients with mesial temporal lobe epilepsy (mTLE) undergoing anterior temporal lobectomy (ATL) or selective amygdalohippocampectomy (SelAH). Method This is a retrospective observational study. The sample included patients with medically refractory mTLE due to unilateral mesial temporal sclerosis who underwent either ATL or SelAH, at Hospital de Clinicas – UFPR, from 2005 to 2012. We report seizure outcomes, using Engel classification, cognitive outcomes, using measurements of verbal and visuospatial memories, as well as operative complications. Result Sixty-seven patients (33 ATL, 34 SelAH) were studied; median follow-up was 64 months. There was no statistically significant difference in seizure or neuropsychological outcomes, although verbal memory was more negatively affected in ATL operations on patients’ dominant hemispheres. Higher number of major complications was observed in the ATL group (p = 0.004). Conclusion Seizure and neuropsychological outcomes did not differ. ATL appeared to be associated with higher risk of complications.

Minimally Invasive Transpalpebral Endoscopic-Assisted Amygdalohippocampectomy

BACKGROUND: Although anterior temporal lobectomy may be a definitive surgical treatment for epileptic patients with mesial temporal sclerosis, it often results in verbal, visual, and cognitive dysfunction. Studies have consistently reported the advantages of selective procedures compared with a standard anterior temporal lobectomy, mainly in terms of neuropsychological outcomes.

OBJECTIVE: To describe a new technique to perform a selective amygdalohippocampectomy (SAH) through a transpalpebral approach with endoscopic assistance.

METHODS: A mini fronto-orbitozygomatic craniotomy through an eyelid incision was performed in 8 patients. Both a microscope and neuroendoscope were used in the surgeries. An anterior SAH was performed in 5 patients who had the diagnosis of temporal lobe epilepsy with mesial temporal sclerosis. One patient had a mesial temporal lesion suggesting a ganglioglioma. Two patients presented mesial temporal cavernomas with seizures originating from the temporal lobe.

RESULTS: The anterior approach allowed removal of the amygdala and hippocampus. The image-guided system and postoperative evaluation confirmed that the amygdala may be accessed and completely removed through this route. The hippocampus was partially resected. All patients have discontinued medication with no more epileptic seizures. The patients with cavernomas and ganglioglioma also had their lesions completely removed. One-year follow-up has shown no visible scars.

CONCLUSION: The anterior route for SAH is a rational and direct approach to the mesial temporal lobe. Anterior SAH is a safe, less invasive procedure that provides early identification of critical vascular and neural structures in the basal cisterns. The transpalpebral approach provides a satisfactory cosmetic outcome.

Neurocognitive and Seizure Outcomes of Selective Amygdalohippocampectomy versus Anterior Temporal Lobectomy for Mesial Temporal Lobe Epilepsy

Objective. To report our institutional seizure and neuropsychological outcomes for a series of patients with mesial temporal lobe epilepsy (mTLE) undergoing anterior temporal lobectomy (ATL) or selective amygdalohippocampectomy (SelAH) between 2004 and 2011. Methods. A retrospective study of patients with mTLE was conducted. Seizure outcome was reported using time-to-event analysis. Cognitive outcome was reported using the change principal in component factor scores, one each, for intellectual abilities, visuospatial memory, and verbal memory. The Boston Naming Test was used for naming assessment. Language dominant and nondominant resections were compared separately. Student's t-test was used to assess statistical significance. Results. Ninety-six patients (75 ATL, 21 SelAH) were included; fifty-four had complete neuropsychological follow-up. Median follow-up was 40.5 months. There was no statistically significant difference in seizure freedom or any of the neuropsychological outcomes, although there was a trend toward greater postoperative decline in naming in the dominant hemisphere group following ATL. Conclusion. Seizure and neuropsychological outcomes did not differ for the two surgical approaches which is similar to most prior studies. Given the theoretical possibility of SelAH sparing language function in patients with epilepsy secondary to mesial temporal sclerosis and the limited high-quality evidence creating equipoise, a multicenter randomized clinical trial is warranted.

Transsylvian selective amygdalohippocampectomy for treatment of medial temporal lobe epilepsy: Surgical technique and operative nuances to avoid complications

Background:

A number of different surgical techniques are effective for treatment of drug-resistant medial temporal lobe epilepsy. Of these, transsylvian selective amygdalohippocampectomy (SA), which was originally developed to maximize temporal lobe preservation, is arguably the most technically demanding to perform. Recent studies have suggested that SA may result in better neuropsychological outcomes with similar postoperative seizure control as standard anterior temporal lobectomy, which involves removal of the lateral temporal neocortex.

Methods:

In this article, the authors describe technical nuances to improve the safety of SA.

Results:

Wide sylvian fissure opening and use of neuronavigation allows an adequate exposure of the amygdala and hippocampus through a corticotomy within the inferior insular sulcus. Avoidance of rigid retractors and careful manipulation and mobilization of middle cerebral vessels will minimize ischemic complications. Identification of important landmarks during amygdalohippocampectomy, such as the medial edge of the tentorium and the third nerve within the intact arachnoid membranes covering the brainstem, further avoids operator disorientation.

Conclusion:

SA is a safe technique for resection of medial temporal lobe epileptogenic foci leading to drug-resistant medial temporal lobe epilepsy.

Alteration of interictal brain activity in patients with temporal lobe epilepsy in the left dominant hemisphere: a resting-state MEG study

Resting MEG activities were compared between patients with left temporal lobe epilepsy (LTLE) and normal controls. Using SAMg2, the activities of MEG data were reconstructed and normalized. Significantly elevated SAMg2 signals were found in LTLE patients in the left temporal lobe and medial structures. Marked decreases of SAMg2 signals were found in the wide extratemporal lobe regions, such as the bilateral visual cortex. The study also demonstrated a positive correlation between the seizure frequency and brain activities of the abnormal regions after the multiple linear regression analysis. These results suggested that the aberrant brain activities not only were related to the epileptogenic zones, but also existed in other extratemporal regions in patients with LTLE. The activities of the aberrant regions could be further damaged with the increase of the seizure frequency. Our findings indicated that LTLE could be a multifocal disease, including complex epileptic networks and brain dysfunction networks.

Evolution of cranial epilepsy surgery complication rates: a 32-year systematic review and meta-analysis

Object

Surgical interventions for medically refractory epilepsy are effective in selected patients, but they are underutilized. There remains a lack of pooled data on complication rates and their changes over a period of multiple decades. The authors performed a systematic review and meta-analysis of reported complications from intracranial epilepsy surgery from 1980 to 2012.

Methods

A literature search was performed to find articles published between 1980 and 2012 that contained at least 2 patients. Patients were divided into 3 groups depending on the procedure they underwent: A) temporal lobectomy with or without amygdalohippocampectomy, B) extratemporal lobar or multilobar resections, or C) invasive electrode placement. Articles were divided into 2 time periods, 1980–1995 and 1996–2012.

Results

Sixty-one articles with a total of 5623 patients met the study's eligibility criteria. Based on the 2 time periods, neurological deficits decreased dramatically from 41.8% to 5.2% in Group A and from 30.2% to 19.5% in Group B. Persistent neurological deficits in these 2 groups decreased from 9.7% to 0.8% and from 9.0% to 3.2%, respectively. Wound infections/meningitis decreased from 2.5% to 1.1% in Group A and from 5.3% to 1.9% in Group B. Persistent neurological deficits were uncommon in Group C, although wound infections/meningitis and hemorrhage/hematoma increased over time from 2.3% to 4.3% and from 1.9% to 4.2%, respectively. These complication rates are additive in patients undergoing implantation followed by resection.

Conclusions

Complication rates have decreased dramatically over the last 30 years, particularly for temporal lobectomy, but they remain an unavoidable consequence of epilepsy surgery. Permanent neurological deficits are rare following epilepsy surgery compared with the long-term risks of intractable epilepsy.

Selective amygdalohippocampectomy versus anterior temporal lobectomy in the management of mesial temporal lobe epilepsy: a meta-analysis of comparative studies

Object

Whether selective amygdalohippocampectomy (SelAH) has similar seizure outcomes and better neuropsychological outcomes compared with anterior temporal lobectomy (ATL) is a matter of debate. The aim of this study was to compare the 2 types of surgery with respect to seizure outcomes and changes in IQ scores.

Methods

PubMed, Embase, and the Cochrane Library were searched for relevant studies published between January 1990 and September 2012. Studies comparing SelAH and ATL with respect to seizure and intelligence outcomes were included. Two reviewers assessed the quality of the included studies and independently extracted the data. Odds ratios and standardized mean deviations with 95% confidence intervals were used to compare pooled proportions of freedom from seizures and changes in IQ scores between the SelAH and ATL groups.

Results

Three prospective and 10 retrospective studies were identified involving 745 and 766 patients who underwent SelAH and ATL, respectively. The meta-analysis demonstrated a statistically significant reduction in the odds of seizure freedom for patients who underwent SelAH compared with those who underwent ATL (OR 0.65 [95% CI 0.51–0.82], p = 0.0005). The differences between the changes in all IQ scores after the 2 types of surgery were not statistically significant, regardless of the side of resection.

Conclusions

Selective amygdalohippocampectomy statistically reduced the odds of being seizure free compared with ATL, but the clinical significance of this reduction needs to be further validated by well-designed randomized trials. Selective amygdalohippocampectomy did not have better outcomes than ATL with respect to intelligence.

Current management and surgical outcomes of medically intractable epilepsy

Epilepsy is one of the most common neurologic disorders in the world. While anti-epileptic drugs (AEDs) are the mainstay of treatment in most cases, as many as one-third of patients will have a refractory form of disease indicating the need for a neurosurgical evaluation. Ever since the first half of the twentieth century, surgery has been a major treatment option for epilepsy, but the last 10-15 years in particular has seen several major advances. As shown in relatively recent studies, resection is more effective for medically intractable epilepsy (MIE) than AED treatment alone, which is why most clinicians now endorse a neurosurgical consultation after approximately two failed regimens of AEDs, ultimately leading to decreased healthcare costs and increased quality of life. Temporal lobe epilepsy (TLE) is the most common form of MIE and comprises about 80% of epilepsy surgeries with the majority of patients gaining complete seizure-freedom. As the number of procedures and different approaches continues to grow, temporal lobectomy remains consistently focused on resection of mesial structures such as the amygdala, hippocampus, and parahippocampal gyrus while preserving as much of the neocortex as possible resulting in optimum seizure control with minimal neurological deficits. MIE originating outside the temporal lobe is also effectively treated with resection. Though not as successful as TLE surgery because of their frequent proximity to eloquent brain structures and more diffuse pathology, epileptogenic foci located extratemporally also benefit from resection. Favorable seizure outcome in each of these procedures has heavily relied on pre-operative imaging, especially since the massive surge in MRI technology just over 20 years ago. However, in the absence of visible lesions on MRI, recent improvements in secondary imaging modalities such as fluorodeoxyglucose positron emission computed tomography (FDG-PET) and single-photon emission computed tomography (SPECT) have lead to progressively better long-term seizure outcomes by increasing the neurosurgeon's visualization of supposed non-lesional foci. Additionally, being historically viewed as a drastic surgical intervention for MIE, hemispherectomy has been extensively used quite successfully for diffuse epilepsies often found in pediatric patients. Although total anatomic hemispherectomy is not utilized as commonly today, it has given rise to current disconnective techniques such as hemispherotomy. Therefore, severe forms of hemispheric developmental epilepsy can now be surgically treated while substantially decreasing the amount of potential long-term complications resulting from cavitation of the brain following anatomical hemispherectomy. Despite the rapid pace at which we are gaining further knowledge about epilepsy and its surgical treatment, there remains a sizeable underutilization of such procedures. By reviewing the recent literature on resective treatment of MIE, we provide a recent up-date on epilepsy surgery while focusing on historical perspectives, techniques, prognostic indicators, outcomes, and complications associated with several different types of procedures.

Anterior temporal lobectomy with amygdalohippocampectomy for mesial temporal sclerosis: predictors of long-term seizure control

Object

In this paper the authors' goal was to identify preoperative variables that predict long-term seizure freedom among patients with mesial temporal sclerosis (MTS) after single-stage anterior temporal lobectomy and amygdalohippocampectomy (ATL-AH).

Methods

The authors retrospectively reviewed 116 consecutive patients (66 females, mean age at surgery 40.7 years) with refractory seizures and pathologically confirmed MTS who underwent ATL-AH with at least 2 years of follow-up. All patients underwent preoperative MRI and video-electroencephalography (EEG); 106 patients (91.4%) underwent Wada testing and 107 patients (92.2%) had neuropsychological evaluations. The authors assessed the concordance of these 4 studies (defined as test consistent with the side of eventual surgery) and analyzed the impact of preoperative variables on seizure freedom.

Results

The median follow-up after surgery was 6.7 years (mean 6.9 years). Overall, 103 patients (89%) were seizure free, and 109 patients (94%) had Engel Class I or II outcome. Concordant findings were highest for video-EEG (100%), PET (100%), MRI (99.0%), and Wada testing (90.4%) and lowest for SPECT (84.6%) and neuropsychological testing (82.5%). Using binary logistic regression analysis (seizure free or not) and Cox proportional hazard analysis (seizure-free survival), less disparity in the Wada memory scores between the ipsilateral and contralateral sides was associated with persistent seizures.

Conclusions

Seizure freedom of nearly 90% can be achieved with ATL-AH in properly selected patients with MTS and concordant preoperative studies. The low number of poor outcomes and exclusion of multistage patients limit the statistical power to determine preoperative variables that predict failure. Strong Wada memory lateralization was associated with excellent long-term outcome and adds important localization information to structural and neurophysiological data in predicting outcome after ATL-AH for MTS.

Trans-middle temporal gyrus selective amygdalohippocampectomy for medically intractable mesial temporal lobe epilepsy in adults: seizure response rates, complications, and neuropsychological outcomes

OBJECTIVE

Selective amygdalohippocampectomy (AHC) has evolved to encompass a variety of techniques to resect the mesial temporal lobe. To date, there have been few large-scale evaluations of trans-middle temporal gyrus selective AHC. The authors examine a large series of patients who have undergone the trans-middle temporal gyrus AHC and assess its clinical and neuropsychological impact.

METHODS

A series of 76 adult patients underwent selective AHC via the trans-middle temporal gyrus approach over a 10-year period, 19 of whom underwent pre- and postoperative neuropsychological evaluations.

RESULTS

Favorable seizure response rates were achieved (92% Engel class I or II), with very low surgical morbidity and no mortality. Postoperative neuropsychological assessment revealed a decline in verbal memory for the left AHC group. No postoperative memory decline was identified for the right AHC group, but rather some improvements were noted within this group.

CONCLUSIONS

The trans-middle temporal gyrus selective AHC is a safe and effective choice for management of medically refractory epilepsy in adults.

Long-term seizure, cognitive, and psychiatric outcome following trans-middle temporal gyrus amygdalohippocampectomy and standard temporal lobectomy

OBJECT

Previous comparisons of standard temporal lobectomy (STL) and selective amygdalohippocampectomy (SelAH) have been limited by inadequate long-term follow-up, variable definitions of favorable outcome, and inadequate consideration of psychiatric comorbidities.

METHODS

The authors performed a retrospective analysis of seizure, cognitive, and psychiatric outcomes in a noncontemporaneous cohort of 69 patients with unilateral refractory temporal lobe epilepsy and MRI evidence of mesial temporal sclerosis after either an STL or an SelAH and examined seizure, cognitive, and psychiatric outcomes.

RESULTS

The mean duration of follow-up for STL was 9.7 years (range 1-18 years), and for trans-middle temporal gyrus SelAH (mtg-SelAH) it was 6.85 years (range 1-15 years). There was no significant difference in seizure outcome when "favorable" was defined as time to loss of Engel Class I or II status; better seizure outcome was seen in the STL group when "favorable" was defined as time to loss of Engel Class IA status (p=0.034). Further analysis revealed a higher occurrence of seizures solely during attempted medication withdrawal in the mtg-SelAH group than in the STL group (p=0.016). The authors found no significant difference in the effect of surgery type on any cognitive and most psychiatric variables. Standard temporal lobectomy was associated with significantly higher scores on assessment of postsurgical paranoia (p=0.048).

CONCLUSIONS

Overall, few differences in seizure, cognitive, and psychiatric outcome were found between STL and mtg-SelAH on long-term follow-up. Longer exposure to medication side effects after mtg-SelAH may adversely affect quality of life but is unlikely to cause additional functional impairment. In patients with high levels of presurgical psychiatric disease, mtg-SelAH may be the preferred surgery type.

Seizure outcomes and mesial resection volumes following selective amygdalohippocampectomy and temporal lobectomy

OBJECT

Anterior temporal lobectomy (ATL) and selective amygdalohippocampectomy (SelAH) are the preferred surgical approaches for the treatment of medically refractory epilepsy involving the nondominant and dominant temporal lobes, respectively. Both techniques provide access to mesial structures-with the ATL providing a wider surgical corridor than SelAH. Because the extent of mesial temporal resection potentially impacts seizure outcome, the authors examined mesial resection volumes, seizure outcomes, and neuropsychiatric test scores in patients undergoing either ATL or transcortical SelAH at a single institution.

METHODS

A retrospective study was conducted in 96 patients with medically refractory mesial temporal lobe epilepsy. Fifty-one patients who had nondominant temporal lobe epilepsy underwent standard ATL, and 45 patients with language-dominant temporal lobe epilepsy underwent transcortical SelAH. Volumetric MRI analysis was used to quantify the mesial resection in both groups. In addition, the authors examined seizure outcomes and the change in neuropsychiatric test scores.

RESULTS

Seizure-free outcome in the entire patient cohort was 94% at a mean follow-up of 44 months. There was no significant difference in the seizure outcome between the 2 groups. The extent of resection of the mesial structures following ATL was slightly higher than for SelAH (98% vs. 91%, p < 0.0001). The change in neuropsychiatric test scores largely reflected the side of surgery, but overall IQ and memory function did not change significantly in either group.

CONCLUSIONS

Transcortical SelAH provides adequate access to the mesial structures, and allows for a resection that is nearly as extensive as that achieved with standard ATL. Seizure outcomes and neuropsychiatric sequelae are similar in both procedures.

Transsylvian-transcisternal selective lesionectomy for pediatric lesional mesial temporal lobe epilepsy

BACKGROUND

The optimal extent of resection for surgical treatment of lesional epilepsy is a controversial issue.

OBJECTIVE

For patients with mesial temporal lobe lesions visible on magnetic resonance imaging, we compared the surgical outcome of selective lesionectomy with that of standard anterior temporal lobectomy (ATL) and amygdalohippocampectomy.

METHODS

We conducted a retrospective analysis of the seizure outcome of 40 patients treated for lesional mesial temporal lobe epilepsy between 1993 and 2008. Before 2006, patients were managed by ATL (n=29) and from 2006 onward, by selective lesionectomy via the transsylvian-transcisternal approach (n=11).

RESULTS

The postoperative seizure-free rates for the 2 groups were comparable: 93% (27/29) for the ATL group and 91% (10/11) for the selective lesionectomy group (P=.814). In both groups, patients with persistent seizures commonly showed incomplete lesion resection, with complete resection often improving seizure outcome. Postoperative visual field defects were more common in the ATL group (21%) than in the selective lesionectomy group (0%) (P=.102).

CONCLUSION

Transsylvian-transcisternal selective lesionectomy is an effective and safe therapeutic modality in children with lesional mesial temporal lobe epilepsy. Completeness of resection is an important variable for seizure control regardless of surgical modality.

Memory outcome after temporal lobe epilepsy surgery: corticoamygdalohippocampectomy versus selective amygdalohippocampectomy

Object

The aim of this study was to compare IQ and memory outcomes at the 1-year follow-up in patients with medically refractory mesial temporal lobe epilepsy (MTLE) due to hippocampal sclerosis. All patients were treated using a corticoamygdalohippocampectomy (CAH) or a selective amygdalohippocampectomy (SelAH).

Methods

The data of 256 patients who underwent surgery for MTLE were retrospectively evaluated. One hundred twenty-three patients underwent a CAH (63 [right side] and 60 [left side]), and 133 underwent an SelAH (61 [right side] and 72 [left side]). A comprehensive neuropsychological test battery was assessed before and 1 year after surgery, and the results were compared between the surgical procedures. Furthermore, seizure outcome was compared using the Engel classification scheme.

Results

At 1-year follow-up, there was no statistically significant difference between the surgical approaches with respect to seizure outcome. Overall, IQ scores showed improvement, but verbal IQ decreased after left SelAH. Verbal memory impairment was seen after left-sided resections especially in cases of SelAH, and nonverbal memory decreased after right-sided resection, especially for CAH. Left-sided resections produced some improvement in nonverbal memory. Older age at surgery, longer duration of seizures, greater seizure frequency before surgery, and poor seizure control after surgery were associated with poorer memory.

Conclusions

Both CAH and SelAH can lead to several cognitive impairments depending on the side of the surgery. The authors suggest that the optimal type of surgical approach should be decided on a case-by-case basis.

The selective amygdalohippocampectomy for intractable temporal limbic seizures

OBJECT

The proximal (anterior) transsylvian approach through a pterional craniotomy was developed by the senior author (M.G.Y.) in 1967 for the microsurgical treatment of saccular aneurysms of the circle of Willis, frontoorbital and temporobasal arteriovenous malformations, cavernomas, and extrinsic and intrinsic tumors. The acquired positive surgical experiences on this large series enabled the senior author, in 1973, to apply this approach for the selective amygdalohippocampectomy in patients with intractable mesial temporal lobe epilepsy.

METHODS

The proximal (anterior) transsylvian-transamygdala approach to the mesial temporal structures permits the selective two-thirds resection of the amygdala and hippocampus-parahippocampus in an anteroinferior to posteroinferior exploration axis along the base of the semicircular temporal horn. This strategy ensures preservation of the overlying neopallial temporal convolutions such as the T1, T2, T3, and T4 gyri as well as the related subcortical connective fiber systems and other essential components of the temporal white matter. The application of rigid brain self-retaining retractor systems was strictly avoided during the entire procedure. Computer-assisted navigation was never used. On routine postoperative CT scanning and MR imaging studies, infarction was not observed in any patient. The availability of tractography technology has proven that the connective fiber system around the resected mesial temporal area remains intact.

RESULTS

The surgical outcome and results on neoplastic and vascular lesions of the mesiobasal temporal region have been presented in Volumes II, IIIB, and IVB of Microneurosurgery. The surgical outcomes and results in 102 patients with mesial temporal seizures who underwent surgery performed by the senior author in Zürich have been previously published. In this paper, 73 patients who underwent surgery between 1994 and September 2006 in Little Rock, Arkansas, are presented, and 13 other patients are excluded who underwent surgery after September 2006. Altogether, among 188 patients who underwent surgery, there was no surgical mortality or morbidity, and no neurological deficits, new neurocognitive dysfunction, or impairments of the preoperative incapacities.

CONCLUSIONS

The surgical outcome in terms of seizures was rewarding in the majority of patients, particularly in those who exhibited the following irregularities on preoperative investigations: regular local dysfunctions on electroencephalography, dysmorphic changes in the mesiobasal temporal parenchyma on MR imaging studies, and hypometabolism in the anterior third of the temporal lobe on PET studies.

Surgery of temporal lobe epilepsy: modalities, advantages, disadvantages and outcomes

From the standard anterior temporal to selective resections, several modalities have evolved in the surgical treatment of temporal lobe epilepsy. In this review, the various surgical approaches, their advantages and disadvantages are discussed from the standpoint of results on seizure tendency, cognitive function, quality of life and technical aspects. Numerous studies, including our own with intracranial recording and reoperations, have provided evidence that the vast majority of temporal lobe seizures arise within the mesial structures. As a result, more and more selective procedures are being carried out directed at the amygdala and hippocampal formation. However, there is still no clear evidence that one selective approach is superior to the more standard temporal resection, which entails removal of the anterior temporal cortex, amygdala and hippocampus, or to any other so-called selective approach in terms of seizure control, cognitive function and quality of life. Technically, in our hands, the transcortical transventricular approach combined with neuronavigation has proven to be safe and less invasive compared with anterior temporal resection. Our experience suggests that the type of resection should be chosen case by case, on an individual basis, determined mainly by symptomatology, imaging, intracranial recording, neuropsychological findings and, at times, by the surgeon‘s experience.

Predictors of outcome after temporal lobectomy for refractory temporal lobe epilepsy

OBJECTIVE

To identify predictors of outcome after epilepsy surgery in patients with temporal lobe epilepsy (TLE).

METHODS

Seventy-six patients with normal magnetic resonance imaging (MRI) or hippocampal sclerosis on MRI who underwent anterior temporal lobe resections were included. Outcome 2 years after surgery was classified as good (Engel I and II) or poor (Engel III and IV). Gender, age at onset and duration of epilepsy, history of febrile convulsions, auras, right- or left-sided TLE, memory ipsilateral to seizure onset (Wada test), hippocampal asymmetry (HA) and T2 relaxation time, amygdala, temporal lobe and hemispheral volume were tested for associations with outcome.

RESULTS

Sixty-seven percent had a good outcome. Of all parameters tested, only a history of febrile convulsions and HA on quantitative MRI were significantly associated with a good seizure outcome. The absence of these parameters did not exclude a good outcome, but only five of 18 patients (28%) without HA and without a history of febrile convulsions had a good outcome.

CONCLUSION

Febrile convulsions and HA were predictors of outcome after epilepsy surgery in TLE. Subtle volume loss in amygdala, temporal lobe or hemispheres and the memory ipsilateral to the side of resection were not associated with outcome.

Temporal lobe epilepsy surgery and the quest for optimal extent of resection: a review

The efficacy of surgery to treat drug-resistant temporal lobe epilepsy (TLE) has been demonstrated in a prospective randomized trial. It remains controversial which resection method gives best results for seizure freedom and neuropsychological function. This review of 53 studies addressing extent of resection in surgery for TLE identified seven prospective studies of which four were randomized. There is considerable variability between the intended resection and the volumetrically assessed end result. Even leaving hippocampus or amygdalum behind can result in seizure freedom rates around 50%. Most authors found seizure outcome in selective amygdalohippocampectomy (SAH) to be similar to that of lobectomy and there is considerable evidence for better neuropsychological outcome in SAH. Studies varied in the relationship between extent of mesial resection and seizure freedom, most authors finding no positive correlation to larger mesial resection. Electrophysiological tailoring saw no benefit from larger resection in 6 of 10 studies. It must be concluded that class I evidence concerning seizure outcome related to type and extent of resection of mesial temporal lobe structures is rare. Many studies are only retrospective and do not use MRI volumetry. SAH appears to have similar seizure outcome and a better cognitive outcome than TLR. It remains unclear whether a larger mesial resection extent leads to better seizure outcome.

Long-term seizure outcome after mesial temporal lobe epilepsy surgery: corticalamygdalohippocampectomy versus selective amygdalohippocampectomy

Object

Resection strategies for the treatment of temporal lobe epilepsy (TLE) are a matter of discussion, and little information is available. The aim of this study was to compare seizure outcomes at the 5-year follow-up in patients with medically refractory unilateral mesial TLE (MTLE) due to hippocampal sclerosis (HS) who were treated using a cortical amygdalohippocampectomy (CorAH) or a selective AH (SelAH).

Methods

The authors obtained data from 100 adult patients who underwent surgery for MTLE. Fifty patients underwent a CorAH and 50 underwent an SelAH. Seizure control achieved with each technique was compared using the Engel classification scheme.

Results

Overall, at the 5-year follow-up, favorable (Engel Classes I and II) seizure outcomes were noted in 82 and 90% of patients who had undergone CorAH and SelAH, respectively. Furthermore, 40% of the patients who had undergone a CorAH and 58% of those who had undergone an SelAH were seizure free (Engel Class Ia). There was no statistically significant difference between the 2 surgical approaches in terms of seizure outcome at the 5-year follow-up (p = 0.38).

Conclusions

Both CorAH and SelAH can lead to similar favorable seizure control in patients with MTLE/HS. However, the authors suggest that the transcortical selective approach has the great advantage of minimizing or completely abolishing the impact of dividing several venous and arterial adhesions which are tedious, time consuming, and, at times, associated with some degree of cerebral swelling.