Electro-clinical characteristics and postoperative outcome of medically refractory tumoral temporal lobe epilepsy

BACKGROUND: Very few studies have specifically addressed surgical treatment and outcome of patients with tumor-related temporal lobe epilepsy (TLE). AIM: To define the postoperative seizure outcome and the factors that influenced the outcome of patients with tumor-related TLE. MATERIALS AND METHODS: We selected patients whose surgical pathology revealed a temporal lobe neoplasm and who had completed > 1 year of postoperative follow-up. We reviewed the clinical, EEG, radiological and pathological data, and the seizure outcome of these patients and assessed the factors that influenced the outcome. RESULTS: Out of the 409 patients who underwent surgery for refractory TLE during the 8-year study period, there were 34 (8.3%) patients with temporal lobe neoplasms. The median age at surgery was 20 years and the median duration of epilepsy prior to surgery was 9.0 years. MRI revealed tumor in the mesial location in 21 (61.8%) patients. Interictal and ictal epileptiform EEG abnormalities were localized to the side of th lesion in the majority. Mesial temporal lobe structures were included in the resection, if they were involved by the tumor; otherwise, lesionectomy alone was performed. During a median follow-up of 4 years, 27 (79%) patients were completely seizure-free. The only factor that predicted long-term seizure-free outcome was being seizure-free during the first two postoperative years. CONCLUSIONS: Our results emphasize the fact that in patients with tumoral TLE, when the seizures are medically refractory, surgery offers potential for cure of epilepsy in the majority.     

Medically refractory epilepsy associated with temporal lobe ganglioglioma: characteristics and postoperative outcome

OBJECTIVES: To define the postoperative seizure outcome and its predictors in patients with ganglioglioma-related temporal lobe epilepsy (TLE). PATIENTS AND METHODS: We reviewed the pre- and post-surgical evaluation data of 23 patients with temporal lobe ganglioglioma, who had completed >or=1 year of postoperative follow-up. They comprised 4.9% of the patients with TLE and 67.6% of the tumoral TLE operated in a developing country epilepsy center during an 8-year period. RESULTS: Median age at surgery was 20 years; median duration of epilepsy prior to surgery was 9 years. Magnetic resonance imaging (MRI) revealed tumor in mesial temporal location in 18 patients (78.3%) and in the lateral location in 2; in the remaining 3, involved both mesial and lateral regions. EEG abnormalities were localized to the side of lesion in the majority. Mesial temporal lobe structures were included in the resection, if they were involved by the tumor; otherwise, lesionectomy alone was performed. During a median follow-up of 4 years, 19 (82.6%) patients were completely seizure-free. Epileptiform abnormalities persisting in the 1-year postoperative EEG predicted unfavorable seizure outcome. CONCLUSION: We emphasize that, in patients with temporal lobe ganglioglioma, when the seizures are medically refractory, surgery offers potential for cure of epilepsy in the majority.     

Seizure outcome after anterior temporal lobectomy and its predictors in patients with apparent temporal lobe epilepsy and normal MRI

PURPOSE: Very little reliable information is available regarding the role of anterior temporal lobectomy (ATL), optimal presurgical evaluation strategy, post-ATL seizure outcome, and the factors that predict the outcome in patients with medically refractory temporal lobe epilepsy (TLE) and normal high-resolution magnetic resonance imaging (MRI). To be cost-effective, epilepsy surgery centers in developing countries will have to select candidates for epilepsy surgery by using the locally available technology and expertise. METHODS: We reviewed the electroclinical and pathological characteristics and seizure outcome of 17 patients who underwent ATL for medically refractory TLE after being selected for ATL based on a noninvasive selection protocol without the aid of positron emission tomography (PET) or single-photon emission computed tomography (SPECT), despite a normal preoperative high-resolution MRI. RESULTS: Seven (41%) patients achieved an excellent seizure outcome; five of them were totally seizure free. An additional five (29%) patients had >75% reduction in seizure frequency. The following pre-ATL factors predicted an excellent outcome: antecedent history of febrile seizures, strictly unilateral anterior temporal interictal epileptiform discharges (IEDs), and concordant type 1 ictal EEG pattern. All the five patients with pathologically verified hippocampal formation neuronal loss were seizure free. The presence of posterior temporal, bilateral temporal, and generalized IEDs portended unfavorable post-ATL seizure outcome. CONCLUSIONS: A subgroup of patients destined to have an excellent post-ATL outcome can be selected from MRI-negative TLE patients by using history and scalp-recorded interictal and ictal EEG data. The attributes of these patients are antecedent history of febrile seizures, strictly unilateral anterior IEDs, and concordant type 1 ictal EEG pattern.     

Foramen ovale electrodes in the preoperative evaluation of temporal lobe epilepsy in children

Purpose:  Foramen ovale electrodes (FOEs) can localize the epileptogenic zone in adults with mesial temporal lobe epilepsy (TLE). Our aim was to investigate the feasibility and safety of using FOEs to investigate refractory TLE in children.
Methods:  Thirty-eight children with seizure semiology and video-EEG (electroencephalography) consistent with medically refractory TLE, and/or the presence of a lesion in the temporal lobe, had FOEs inserted. Complications occurring during the monitoring and up to 3 months after surgery and the long-term seizure outcome were registered.
Results:  Forty electrodes were placed in 38 patients. The mean age of the patients was 9.8 years (range 2.3–15.4 years). FOEs confirmed a unilateral mesial temporal lobe seizure onset in 14 patients, onset in both FOEs and lateral electrodes in two patients, and onset in the anterior temporal electrodes in only one patient. Six patients had seizures recorded but were not considered surgical candidates; four patients had no seizures recorded, and 11 patients were further investigated with depth electrodes. One patient (2.6%) developed a hematoma in the cheek, and in two patients the electrodes were extracranial but could still be used for recording. Twenty-eight children had a temporal resection; 25 were Engel class I at follow-up.
Discussion:  FOEs are safe to use in children and provide valuable information on the mesial temporal lobe structures in the preoperative investigation of pediatric TLE. Patient selection for FOE investigation is, however, essential for a conclusive result.     

Predictors of psychiatric and seizure outcome following temporal lobe epilepsy surgery

Purpose: Neurosurgery is an effective therapy for selected individuals with medically refractory temporal lobe epilepsy (TLE). De novo psychopathology may complicate the postsurgical outcome. Our aims were to identify predictors of de novo psychiatric and seizure outcome following TLE surgery. Methods: Medical records of 280 patients who underwent TLE surgery were reviewed. Preoperative and postoperative psychiatric diagnoses were identified, in addition to information on seizure recurrence and neuropsychological status. Logistic regression analysis was used to identify predictors of having a de novo psychiatric diagnosis and remaining seizure‐free within 4 years following surgery. Key Findings: One hundred five patients (38%) had significant psychiatric problems within 4 years following TLE surgery. Fifty‐one patients (18%) developed de novo psychopathology; half of cases presented within 6 months and 90% of psychopathologies persisted 6 months or longer. A preoperative history of secondary generalized tonic–clonic seizure(s) (SGTCS) was an independent predictor of de novo psychopathology (odds ratio [OR] 2.73, 95% confidence interval [CI] 1.14–6.59, p = 0.02). From patients with available seizure data, 49% (127 of 258) remained seizure‐free for 4 years after surgery. Patients with a history of SGTCS (OR 0.47, 95% CI 0.25–0.90, p = 0.02) and those with a preoperative psychiatric diagnosis (OR 0.53, 95% CI 0.28–0.98, p = 0.04) were significantly less likely to remain seizure‐free. Significance: De novo psychopathology is a significant complication of TLE surgery. Inclusion of neuropsychiatric assessments in the presurgical evaluation may lead to increase in the power of prognostic models used to predict the neurologic outcome of TLE surgery.     

Kaplan-Meier analysis on seizure outcome after epilepsy surgery: do gender and race influence it?

OBJECTIVE: To evaluate seizure outcome following epilepsy surgery for patients with temporal lobe epilepsy and evaluate is gender and race/ethnicity influence it. METHODS: Data were obtained from the discharge database of the University of Alabama at Birmingham, Epilepsy Center, between 1985 and 2001. The sample consisted of all patients with a primary diagnosis of medically intractable temporal lobe epilepsy (TLE) who underwent anterior temporal lobectomy. Seizure recurrence was tabulated at 7 days, 2 months, 6 months, 1, 2, 3, 4, 5, and 6 years following surgery. Logistic regression analysis was used to model the presence of seizure recurrence after anterior temporal lobectomy for all patients. Kaplan-Meier analysis was done to obtain estimates and 95% CIs of seizure freedom from baseline. Baseline variables--age at surgery, age at seizure onset, sex, side of resection, immediate postoperative seizures, and pathology results--were assessed as potential predictors of each outcome by comparing the survival curves within each variable with a log rank test. RESULTS: Three hundred sixty-eight patients underwent surgical treatment for TLE, mean age of 30.2 years. Thirty-five patients were African American, 43% were men. Immediate postoperative seizures were seen in 23 patients, while seizure recurrence occurred in 27.3% patients within a year after surgery, and in 33.6% within 6 years. Logistic regression results showed no differences between African Americans and whites, between males and females. The occurrence of immediate postoperative seizures was a strong predictor of late seizure recurrence only at 1 year after surgery. CONCLUSIONS: The occurrence of seizures in the immediate postoperative period is a strong predictor of later seizure recurrence. Sex and race/ethnicity do not appear to be predictors of long-term outcome following surgery for temporal lobe epilepsy.     

Prognostic factors for surgery of neocortical temporal lobe epilepsy.

OBJECTIVES: In the current classification of epilepsies two forms of temporal lobe epilepsy (TLE) were included: mesial and lateral (neocortical) TLE. We aimed at identifying prognostic factors for the surgical outcome of lesional neocortical TLE. METHODS: We included consecutive patients who had undergone presurgical evaluation including ictal video-EEG and high-resolution MRI, who had TLE due to neocortical lateral epileptogenic lesions, who had a lesionectomy and who had >2-year follow-up. RESULTS: There were 29 patients who met the inclusion criteria. Twenty of them became postoperatively seizure-free. Patients' mean age was 34.8+/-9 years (range 18-52). The age at epilepsy onset was 20.1+/-8 years. We found that left-sided surgery (p=0.048) and focal cortical dysplasia (FCD) on MRI (p=0.005) were associated with non-seizure-free outcome, while lateralized/localized EEG seizure pattern (p=0.032), tumors on the MRI (p=0.013), and a favorable seizure situation at the 6-month postoperative evaluation were associated with 2-year postoperative seizure-freedom (p<0.001). Multivariate analysis indicated that the side of surgery was not an independent predictor. CONCLUSION: More than two-thirds of the patients with neocortical TLE became seizure-free postoperatively. Lateralized/localized EEG seizure pattern and tumors on the MRI were associated with postoperative seizure-freedom, while FCD were associated with a poor outcome. The 6-month postoperative outcome is a reliable predictor for the long-term outcome.     

Failed surgery for temporal lobe epilepsy: predictors of long-term seizure-free course

OBJECTIVES: To identify prognostic factors which predict the outcome 2 years after TLE surgery in those patients who were not seizure-free at the 6-month postoperative examination. METHODS: We included 86 postoperative TLE patients who had undergone presurgical evaluation, including video-EEG and high-resolution MRI, and who had seizures between the second and sixth postoperative months. RESULTS: 32% of patients were seizure-free in the second postoperative year. We found that normal MRI findings and secondarily generalized seizures (SGTCS) preoperatively were associated with a non-seizure-free outcome, while rare postoperative seizures and ipsilateral temporal IED with seizure-free outcome. Newly administered levetiracetam showed a significant positive effect on the postoperative outcome independent of other prognostic factors. Five of seven patients who received levetiracetam became seizure-free (p = 0.006). CONCLUSION: One-third of patients who did not become seizure-free immediately after surgery, eventually achieved long-term seizure freedom. We suggest watching for long-term seizure freedom after failed epilepsy surgery especially in patients who had rare postoperative seizures, focal MRI abnormality, ipsilateral temporal spikes, or no SGTCS preoperatively. Levetiracetam may have a positive effect on postsurgical seizures.     

Response to first drug trial predicts outcome in childhood temporal lobe epilepsy.

OBJECTIVE: To construct a clinical prediction model for the early identification of children destined to develop refractory temporal lobe epilepsy (TLE) 2 years after epilepsy onset. METHODS: Patients with TLE between 1 and 18 years old seen in the Division of Neurology at Children's Hospital of Philadelphia during 1999 were identified through billing records and chart review. Data were abstracted independently on 5 candidate predictor variables for refractory TLE and on seizure frequency outcome at 2 years after epilepsy onset. RESULTS: One hundred twenty patients met inclusion criteria and had at least 2 years of follow-up. Forty-five of 120 patients (37.5%) had refractory TLE at 2 years after onset, and 75 of 120 (62.5%) were seizure free. Three significant predictors of refractory TLE were found on bivariate analysis: an early risk factor for epilepsy (risk ratio = 3.5 [95% CI 2.2, 5.6]), temporal lobe abnormality on MRI scan (2.9 [95% CI 1.9, 4.6]), and failure of the first antiepileptic drug (AED) trial (16.5 [95% CI 6.3, 43.9]). Logistic regression indicated that the best model to predict refractory TLE contained only the variable "failure of first AED trial," with a positive predictive value of 0.89 (95% CI 0.76, 0.96) and negative predictive value of 0.95 (95% CI 0.87, 0.99) to predict "refractory TLE" at 2 years. CONCLUSIONS: Failure of first AED trial accurately predicts refractory TLE at 2 years after onset, based on retrospective cohort data in children. If verified prospectively and with longer follow-up, this finding should support earlier consideration of surgical options.     

Outcome predictors for surgical treatment of temporal lobe epilepsy with hippocampal sclerosis

Purpose: To study long-term postoperative course and identify predictors for postoperative seizure control in patients with medically intractable temporal lobe epilepsy (TLE) associated with hippocampal sclerosis (HS), diagnosed by magnetic resonance imaging (MRI), and ascertained histopathologically. To compare patients becoming seizure-free (i.e., cured from epilepsy) and patients experiencing prolonged seizure-free periods interposed with recurring seizures.
Methods: One hundred thirty-five patients (74 women) underwent complete evaluation for epilepsy surgery. The predictive value of duration of epilepsy, age at onset, age at surgery, gender, febrile convulsion history, ictal dystonic posturing, unilateral interictal electroencephalography (EEG) discharges (IED), preoperative secondarily generalized tonic–clonic seizures (SGTCS), and preoperative seizure frequency for short- and long-term postoperative seizure control were evaluated with two classification systems: Classification 1 (seizure-freedom with or without auras during 12-months before observation points) and the stringent classification 2 [International League Against Epilepsy (ILAE) Ia; absolute absence of seizures and auras after operation].
Results: Unilateral IED at year 1 and 2 (p = 0.037 and p = 0.034), male gender and low seizure frequency at year 2 (p = 0.013 and p = 0.046) were significant predictors for seizure freedom using classification 1. All variables (except male gender at year 2; p = 0.035) lost their predictive power, applying classification 2. The proportion of seizure-free patients remained stable between 70% to 79% with classification 1, but decreased from 64.4% at year 1 to 45.8% at year 5 with classification 2.
Discussion: Positive predictors of short-term outcome do not predict long-term outcome in patients with TLE associated with HS. Absolute freedom of seizures and auras cannot be predicted by conventional preoperative variables.     

Type of preoperative aura may predict postsurgical outcome in patients with temporal lobe epilepsy and mesial temporal sclerosis

PurposeAs the initial symptoms of epileptic seizures, many types of auras have significant localizing or lateralizing value. In this study, we hypothesized that the type of aura may predict postsurgical outcome in patients with medically refractory temporal lobe epilepsy (TLE) and mesial temporal sclerosis (MTS).MethodsIn this retrospective study, all patients with a clinical diagnosis of medically refractory TLE due to unilateral mesial temporal sclerosis who underwent epilepsy surgery at the Jefferson Comprehensive Epilepsy Center were recruited. Patients were prospectively registered in a database from 1986 through 2014. Postsurgical outcome was classified into two groups: seizure freedom or relapse. Outcome was compared between seven groups of patients according to their preoperative auras.ResultsTwo hundred thirty-seven patients were studied. The chance of becoming free of seizures after surgery in patients with abdominal aura was 65.1%, while in other patients, this was 43.3% (P = 0.01). In two-by-two comparisons, no other significant differences were observed.ConclusionPatients with medically refractory TLE–MTS who reported abdominal auras preceding their seizures fared better postoperatively with regard to seizure control compared with those who did not report auras, which may indicate bitemporal dysfunction, and to patients with other auras, which may indicate a widespread epileptogenic zone in the latter group of patients.     

Temporal lobe epilepsy with bilateral seizure origin studied by [18F]FDG-positron emission tomography

Nine patients who underwent presurgical evaluation because of medically refractory temporal lobe epilepsy (TLE) showed either unilateral, although alternating in side, or bilateral simultaneous seizure onsets in both temporal lobes (TL). EEG recordings with semi-invasive foramen ovale electrodes revealed in seven patients a predominance of seizure onset in one TL of between 50% and 88%. In two patients the majority of seizures originated simultaneously in both TL. In four patients a unilateral selective amygdalohippocampectomy resulted in a good to excellent seizure outcome without noteworthy memory deficits and confirmed the preoperative lateralization of the primary epileptogenic focus by interictal ¹⁸F-fluorodeoxyglucose positron emission tomography (PET). Five patients were rejected from surgery due to strong bilaterality of their epilepsy and/or divergent presurgical findings. PET contributed to the decision of whether surgery should be performed: all patients who underwent surgery had a unilateral TL hypometabolism which was concordant with the findings of other tests. Patients in whom surgery was denied had either bilateral temporal hypometabolism or the PET findings were discordant with other results obtained during the presurgical evaluation.     

Long-term follow-up outcome after surgical treatment for lesional temporal lobe epilepsy

OBJECTIVES: Lateral or neocortical temporal lobe epilepsy (TLE) is regarded as a distinct clinical entity from medial TLE. Surgery for neocortical TLE can be considered as a viable treatment option; however, there is very limited information available on aspects such as long-term seizure outcome. Thus, we retrospectively reviewed our ten surgical cases of lateral TLE with a minimum 2 year follow-up outcome. METHODS: The series comprised four male and six female patients, ranging in age from 3 to 46 years (mean: 28.8 years). Seven cases were found to be drug-resistant. Invasive pre-surgical evaluation for intractable epilepsy was performed in six patients. RESULTS: The pathologic lesions were removed completely in nine cases. Lesionectomy alone was performed in four cases and total epileptogenic focus resection was confirmed in four cases. The epileptogenic regions within eloquent areas were preserved in two cases. The medial temporal structure was intact and preserved in all cases. Neuropathologic diagnoses were cavernoma in three cases, astrocytoma (grade 2) in two cases, arteriovenous malformation in two cases, gliosis in two cases and ganglioglioma in one case. The mean duration of follow-up was 6.5 years (range: 2.2-9.3 years). Outcomes categorized according to Engel classes were class I (E1) in six cases and class II (E2) in four cases. Patients who had post-operative seizures may also achieve long-term seizure decrease or freedom in three cases: case 5 (E4-E2), case 6 (E4-E2) and case 7 (E3-E1). Thus, worthwhile improvement was achieved in 100% of the cases in this series, with 60% of patients being seizure-free during the followed-up period. CONCLUSIONS: The controlled long-term follow-up results suggested that surgery for lesional TLE can be considered as a viable treatment option to control seizure with a low morbidity rate and good outcomes.     

Surgical treatment for refractory temporal lobe epilepsy in the elderly: seizure outcome and neuropsychological sequels compared with a younger cohort

PURPOSE: Surgical treatment of refractory temporal lobe epilepsy (TLE) is promising for selected patients, but only little experience has been acquired in operating on older patients, especially with limited resections. We intend to delineate clinical and surgical factors influencing outcome in patients older than 50 years at operation and to compare the results with those of a younger patient cohort. METHODS: Fifty-two patients older than 50 years were operated on for intractable mesial or combined mesiolateral TLE between 1991 and 2002. The mean age at operation was 55 years, and the mean duration of epilepsy was 33 years. Forty selective amygdalohippocampectomies (33 for hippocampal sclerosis, seven for removal of a mesiotemporal lesion), five lateral temporal lesionectomies plus amygdalohippocampectomy, and seven anterior temporal lobectomies were performed. Eleven (21%) patients had undergone invasive presurgical video-EEG monitoring. The mean follow-up period was 33 months. We compared the results with those of a younger cohort operated on in the same time period. RESULTS: Thirty-seven older patients attained complete seizure control (71% class I), and 10 patients had only rare postoperative seizures (19% class II). Four patients improved >75% (8% class III), and one patient did not improve (2% class IV). The same rate of seizure control was attained by 11 patients older than 60 years at surgery. These results were not significantly different from those in a younger patient group. A trend toward better seizure control was noted in 16 patients with an epilepsy duration of <30 years (all class I or II), and in 20 patients with a seizure frequency of fewer than five seizures per month (all class I or II). No mortality resulted from a total of 65 diagnostic and therapeutic procedures. A 3.8% permanent neurologic morbidity (dysphasia and hemiparesis) was noted. Hemianopia occurred in three (5.9%) patients. Neuropsychological testing revealed low preoperative performances and some gradual further deterioration after surgery. CONCLUSIONS: Results of surgery for TLE with mainly limited resections are promising in patients older than 50 years and older 60 years, despite the long seizure history. As expected, the risk of complications is somewhat higher compared with that in a younger control group. The impact of low neuropsychological performance is a concern.     

Long-term seizure outcome and antiepileptic drug treatment in surgically treated temporal lobe epilepsy patients: a controlled study

PURPOSE: To evaluate the long-term impact of surgical treatment on seizure outcome and antiepileptic drug (AED) use in patients with pharmacoresistant temporal lobe epilepsy (TLE). METHODS: Comparison of seizure outcome and AED us in operated-on TLE patients (n=148) and nonsurgically treated TLE patients (n=94) at a baseline visit and a follow-up visit after a mean period of 4.8 years. RESULTS: At follow-up, 44.6% of the surgical patients and 4.3% of the nonsurgical patients had been continuously seizure- free since the baseline visit (including the immediate postoperative period). A further 17.6% of the operated-on and 3.2% of the not operated-on patients had been seizure-free for at least the previous year; 37.8% of the surgical and 92.5% of the nonsurgical patients had had seizures during the previous 12 months (p < 0.001). Of the surgical patients, 8.8% versus none of the nonsurgical patients were AED free at follow-up; 55.4% versus 20.2% were receiving monotherapy, and 35.8% versus 79.8% were receiving polytherapy (p < 0.001). Mean number of AEDs and mean change in number of AEDs were significantly more favorable in operated-on than in non-operated-on patients. Further subgroup analysis revealed that not only the continuously seizure-free surgical patients, but also the operated-on patients with ongoing seizures took fewer AEDs than their respective non-operated-on counterparts. CONCLUSIONS: This controlled study for the first time provides comprehensive information on long-term seizure outcome and AED use in surgical TLE patients. It shows a more favorable seizure outcome and AED use in the surgically treated patients. The latter holds true even for the not seizure-free patient subgroup.     

Postoperative EEG and seizure outcome in temporal lobe epilepsy surgery.

OBJECTIVE: To assess the prognostic value of scalp electroencephalogram (EEG) after epilepsy surgery, we investigated whether postoperative EEG abnormalities (interictal epileptiform discharges, IED; interictal slow activity, ISA) were associated with seizure outcome and other patient characteristics after resective surgery in patients with temporal lobe epilepsy (TLE). METHODS: Sixty-two patients with medically refractory TLE who underwent surgery were studied. Patients were categorized according to etiology (mesiotemporal sclerosis vs. tumors/cortical dysplasias); extent of surgical resection (extensive vs. limited); and amount of preoperative IED on wake EEG (oligospikers, <1 IED/h, vs. spikers). Patients were also classified as seizure-free (SF) or having persistent seizures/auras (not-SF) during follow up visits 1 month and 1 year after surgery. Preoperative 60-min interictal EEGs were evaluated for IED and ISA, and compared to postoperative wake EEGs. RESULTS: Seizures/auras persisted in 16/62 (25.8%) patients at 1 month and in 8/62 (12.9%) at 1 year follow up. ISA was not significantly related to outcome. Of 42 patients with EEG negative for IED at 1 month, 4 were not-SF; at 1 year, one of 44 such patients was not-SF. IED was significantly associated with seizure/aura persistence in patients categorized as mesiotemporal sclerosis and with extensive surgery. Oligospikers and spikers on preoperative EEG showed no differences in the postoperative seizure outcome, excellent in both cases; moreover, the presence of postoperative IEDs indicated auras/seizures persistence apart from the preoperative EEG spike frequency. CONCLUSIONS: Our study showed that the presence of IED of postoperatve EEG strongly indicates seizure/aura persistence. Therefore, serial EEGs should be included in postoperative follow up schedules as a crucial tool in evaluating seizure outcome.     

Tailored anteromedial lobectomy in the treatment of refractory epilepsy of the temporal lobe: long term surgical outcome and predictive factors

OBJECTIVE: To analyze long-term results and to determine prognostic factors on seizure outcome in a series of patients with temporal lobe epilepsy (TLE) who underwent anteromedial temporal lobectomy (AMTL). MATERIALS AND METHODS: From 1995 to 1998 forty-two patients suffering from non-lesional TLE underwent tailored AMTL at our Institution. We retrospectively reviewed surgical results and calculated predictive factors of good outcome in the long term. RESULTS: Sixty-four percent of patients were rendered seizure free (median follow up 60 months). Eleven cases (26.2%) had a significant reduction of disabling epileptic episodes. Poor seizure control was observed in four patients (9.5%). Overall surgical morbidity was 4.7%. Medial temporal sclerosis (MTS) was the most common histopathological finding (69% of cases). The presence of unilateral hippocampal abnormalities on qualitative MRI was significantly associated with excellent postoperative outcome (p<0.011). Qualitative preoperative MRI had a positive predictive value of 83% in detecting both MTS at pathological examination and excellent outcome. CONCLUSIONS: Tailored AMTL is a safe and effective procedure in the treatment of selected patients with medically refractory TLE. Data from preoperative qualitative MRI well correlated with histopathological findings. The presence of unilateral hippocampal atrophy on qualitative MRI was predictive of excellent outcome in the long-term follow up.     

Hyperkinetic seizures in patients with temporal lobe epilepsy: clinical features and outcome after temporal lobe resection

Purpose: Temporal lobe epilepsy (TLE) is usually associated with automatisms. Hyperkinetic seizures are supposed to be unusual. Because we witnessed several patients with TLE and ictal hyperkinetic symptoms, we retrospectively assessed the number, clinical findings, and seizure outcome in such patients who had undergone temporal lobe resection. Methods: We reviewed medical history, video–electroencephalography (EEG) recording and neuroimaging of adult patients who underwent epilepsy surgery for TLE at the Kork Epilepsy Center over the last 20 years with a minimum postoperative follow‐up of 12 months. Key Findings: Among 294 patients who were resected exclusively in the temporal region, we identified 17 (6%) who presented with hyperkinetic semiology such as violent vocalization, complex movements of the proximal segments of the limbs, rotation of the trunk, pelvic thrusting, or early tonic or dystonic posturing. Most of the patients had a preceding aura. Ictal EEG activity was located in the corresponding temporal region, usually with a wide distribution over temporal electrodes with fast spread to unilateral frontal electrodes and to the contralateral side. Neuroimaging revealed extended lesions in the temporal lobe involving mesial and neocortical structures. Most of the patients underwent classical anterior temporal lobe resection including amygdalo‐hippocampectomy. Fourteen patients (82%) became completely seizure‐free (Engel class Ia). Histopathology showed mainly focal cortical dysplasia plus hippocampal sclerosis. Significance: Hyperkinetic seizure semiology may occasionally occur in patients with TLE and is, therefore, no contradiction to the hypothesis of TLE if scalp EEG patterns and neuroimaging findings correspond. The postoperative seizure outcome is favorable in such patients and not different from outcome data in classical TLE.     

"MRI-negative PET-positive" temporal lobe epilepsy: invasive EEG findings, histopathology, and postoperative outcomes

The aim of this retrospective study was to analyze invasive EEG findings, histopathology, and postoperative outcomes in patients with MRI-negative, PET-positive temporal lobe epilepsy (TLE) (MRI–/PET + TLE) who had undergone epilepsy surgery. We identified 20 patients with MRI-/PET + TLE (8.4% of all patients with TLE who had undergone surgery; 11 men, 9 women). Of the 20 patients, 16 underwent invasive EEG. The temporal pole and hippocampus were involved in the seizure onset zone in 62.5% of the patients. We did not identify a lateral temporal or extratemporal seizure onset in any patient. Of the 20 patients, 17 had follow-up periods > 1 year (mean follow-up = 3.3 years). At the final follow-up, 70.6% patients were classified as Engel I, 5.8% of patients as Engel II, and 11.8% of patients as Engel III and IV (11.8%). Histopathological evaluation showed no structural pathology in any resected hippocampus in 58% of all evaluated temporal poles. The most common pathology of the temporal pole was focal cortical dysplasia type IA or IB. MRI–/PET + TLE should be delineated from other “nonlesional TLE.” The ictal onset in these patients was in each case in the temporal pole or hippocampus, rather than in the lateral temporal neocortex. Standard surgery produced a good postoperative outcome, comparable to that for patients with lesional TLE. Histopathological findings were limited: the most common pathology was focal cortical dysplasia type I.     

Epilepsy surgery outcomes in temporal lobe epilepsy with a normal MRI

Purpose:   To determine the long-term efficacy of anterior temporal lobectomy for medically refractory temporal lobe epilepsy in patients with nonlesional magnetic resonance imaging (MRI).
Methods:   We identified a retrospective cohort of 44 patients with a nonlesional modern "seizure protocol" MRI who underwent anterior temporal lobectomy for treatment of medically refractory partial epilepsy. Postoperative seizure freedom was determined by Kaplan-Meyer survival analysis. Noninvasive preoperative diagnostic factors potentially associated with excellent surgical outcome were examined by univariate analysis in the 40 patients with follow-up of >1 year.
Results:   Engel class I outcomes (free of disabling seizures) were observed in 60% (24 of 40) patients. Preoperative factors associated with Engel class I outcome were: (1) absence of contralateral or extratemporal interictal epileptiform discharges, (2) subtraction ictal single photon emission computed tomography (SPECT) Coregistered to MRI (SISCOM) abnormality localized to the resection site, and (3) subtle nonspecific MRI findings in the mesial temporal lobe concordant to the resection.
Discussion:   In carefully selected patients with temporal lobe epilepsy and a nonlesional MRI, anterior temporal lobectomy can often render patients free of disabling seizures. This favorable rate of surgical success is likely due to the detection of concordant abnormalities that indicate unilateral temporal lobe epilepsy in patients with nonlesional MRI.