Does intraoperative electrocorticography alter seizure outcomes after temporal lobe epilepsy surgery?

<h3>Objective:</h3> To determine the long-term seizure freedom and resolution of epilepsy in patients with drug resistant Temporal Lobe Epilepsy (TLE) and a clear-cut MRI lesion. <h3>Background:</h3> The long-term seizure free outcomes following surgery for TLE varied widely from 41% – 80% following surgery for TLE. <h3>Design/Methods:</h3> In a retrospective, longitudinal cohort study, we analysed the presurgical, surgical and post-surgical parameters to determine the seizure freedom and resolution of epilepsy in patients with 'drug resistant lesional TLE with at least 10 years or more of post-surgery follow-up. The Study period was from June 2001 to 2012 <h3>Results:</h3> Of the 259 patients who formed the study population, 46% were women. The duration of follow-up ranged from 10 to 21 years. The average age at surgery was 25.80 ± 11.32 yrs; 49% had an aura, 61% had only hypomotor seizures and 38% had psychiatric comorbidity. The commonest pathology was hippocampal sclerosis(70%) followed by tumoral lesions and focal cortical dysplasia; 9.8% had acute post-operative seizures. At latest follow-up 75.6% were seizure free of which 52% had resolution of epilepsy. Presence of an aura , hippocampal sclerosis and longer time to first post-operative seizure were strong predictors for resolution of epilepsy while acute post-operative seizures and an abnormal post-surgery EEG at 1 year were predictors of persistent seizures. On survival analysis, the time to first seizure was significantly early in patients with persistent seizures. Seizure freedom both at three and five years predicted seizure freedom at 10 years. <h3>Conclusions:</h3> Resective surgery for drug resistant lesional TLE was associated with higher rate of seizure-freedom in ~75% and resolution of epilepsy in 52.15% even at long term follow-up. Longer time to first seizure, presence of aura at presentation and hippocampal sclerosis are strong predictors for resolution of epilepsy. APOS and abnormal Post-Surgery inter-ictal EEG are predictors of unfavourable outcome. <b>Disclosure:</b> Dr. Sattaluri has nothing to disclose. Dr. Patil has nothing to disclose. Dr. Choudhary has nothing to disclose. Dr. Vooturi has nothing to disclose.

To explore the effect of duration of epilepsy and delay in surgery on seizure outcome in patients operated for drug-resistant temporal lobe epilepsy (TLE). A total of 664 consecutive patients who underwent anterior temporal lobectomy (ATL) for TLE from 1995 to 2008 formed the study cohort. We divided them into two, one as seizure-free with or without antiepileptic drugs after ATL as "good outcome" (Engel class I a) and seizures of any type, any time after surgery as "poor outcome." The probability of seizure freedom/seizure recurrence based on the duration of epilepsy was compared using Kaplan-Meier curves, univariate Cox regression survival analysis, and multivariate Cox proportional hazards regression model. A total of 136 children and 528 adults underwent ATL during this period. Mean duration of epilepsy pre-ATL was 17.1+9.4years. At mean follow-up of 8.5years, 331 patients (49.8%) had good outcome and 333 (50.2%) had poor outcome. The hazard of seizure recurrence linearly increased with duration of epilepsy pre-ATL, from 1.5 (duration of epilepsy, 5-10years) to 1.9 (duration of epilepsy, 10-15years) to 2 (duration of epilepsy over 15years). In addition, encephalitis as antecedent, bilateral mesial temporal sclerosis in MRI, normal histopathology, and spikes in postoperative EEG at 3months and 1year predicted poor seizure outcome. "Epilepsy duration" independently predicted both short- and long-term seizure outcome after surgery in TLE. "Lost years" translate into poor seizure outcome after ATL. Therefore, all cases of drug-resistant TLE should be referred to a surgical center at the earliest.

Anterior temporal lobectomy (ATL) within the language-dominant hemisphere can impair naming. This prospective study examined the pre-operative to post-operative course of different language components, clarifying which changes are relevant within the short-term and long-term outcome of language. Patients with drug-resistant temporal lobe epilepsy (TLE) were evaluated using the Token, Boston Naming and Word Fluency tests assessing sentence comprehension and word-finding on visual, semantic or phonemic cues. A total of 106 patients were evaluated before and 6 months, 1 and 2 years after ATL; 60 patients were also evaluated after 5 years and 38 controls were assessed at baseline. Seizure outcome was comparable between the left and right TLE patients. Before surgery, naming and word fluency were impaired in the left and right TLE patients, whereas sentence comprehension was normal. After left or right ATL, word fluency progressively improved, naming showed early worsening and late improvement after left ATL and progressive improvement after right ATL, and sentence comprehension did not change. At the 5-year follow-up, naming improvement was clinically significant in 31% and 71% of the left and right TLE patients, respectively. Pre-operative naming, ATL laterality, schooling, and post-operative seizure frequency and number of antiepileptic drugs predicted post-operative naming. Pre-operative word fluency and schooling predicted post-operative word fluency. Left or right TLE can impair word-finding but not sentence comprehension. After ATL, word-finding may improve for a long time, depending on TLE laterality, seizure control and mental reserve. These findings may clarify prognosis prior to treatment.

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

The authors of this study aimed to investigate surgical outcomes and prognostic factors in older patients with drug-resistant temporal lobe epilepsy (TLE) who had undergone resective surgery. Data on patients older than 45 years of age with drug-resistant TLE who had undergone resective surgery at Sanbo Brain Hospital, Capital Medical University, between January 2009 and August 2017 were retrospectively collected. Postoperative seizure outcomes were evaluated according to the International League Against Epilepsy (ILAE) classification. Patients belonging to ILAE classes 1 and 2 were classified as having a favorable outcome, whereas patients belonging to ILAE classes 3-6 were classified as having an unfavorable outcome. Univariate analysis and multivariate logistic regression analysis were used to identify the potential predictors of seizure outcomes. A total of 45 patients older than 45 years of age who had undergone resective epilepsy surgery for TLE were included in the present study. Eight (17.8%) of 45 patients had preoperative comorbidity in addition to seizures. The average age at the time of surgery was 51.76 years, and the average duration of epilepsy at the time surgery was 18.01 years. After an average follow-up period of 4.53 ± 2.82 years (range 2-10 years), 73.3% (33/45) of patients were seizure free. Surgical complications were observed in 13.3% of patients. Univariate and multivariate analyses revealed that an MRI-negative finding is the only independent predictor of unfavorable seizure outcomes (OR 0.06, 95% CI 0.01-0.67, p = 0.023). Resective surgery is a safe and effective treatment for older patients with drug-resistant TLE. An MRI-negative finding independently predicts unfavorable seizure outcomes.

Pathology-Based Approach to Seizure Outcome After Surgery for Pharmacoresistant Medial Temporal Lobe Epilepsy

Selective amygdalohippocampectomy versus standard temporal lobectomy in patients with mesial temporal lobe epilepsy and unilateral hippocampal sclerosis

Corpus callosotomy: A palliative therapeutic technique may help identify resectable epileptogenic foci

To assess the significance of symptomatic hemorrhagic complications occurring after different temporal resections for temporal lobe epilepsy (TLE) and to compare this data to findings with postoperative hematomas after temporal surgery for mostly glial or metastatic tumors. Patient charts were retrospectively reviewed for 442 patients who underwent surgery for refractory TLE between 1995 and 2000. Procedures were 247 transsylvian amygdalohippocampectomies (AH), 40 transcortical AH, 57 anterior temporal lobectomies (ATL), 23 lesionectomies plus AH, and 75 lesionectomies without AH. All patients with delayed awakening or new neurological deficits due to hemorrhages were included in the study. An identical procedure was performed to detect symptomatic hemorrhages after 208 procedures for temporal tumor resection during the same time period. Symptomatic postoperative hemorrhages were found in 17 patients (3.8 %) undergoing epilepsy surgery, while the incidence was 3.0 % in a group with space-occupying temporal tumors (six patients). Hemorrhages showed a characteristic distribution after epilepsy surgery: in eight patients they were located remote from the site of surgery in the upper cerebellar vermis and foliae. Five typical hemorrhages associated with dysphasia were found in the left frontal operculum, only three patients had hematomas in the resection cavity, and one was located epidurally. Two patients had more than one location of hemorrhage. Transsylvian AH and ATL had a similar risk for postoperative hemorrhage, whereas none was found after lateral lesionectomies or transcortical AH. Intraoperative manipulations were associated with opercular hemorrhages; the only predisposing factor for resection site hematomas was older age, whereas cerebellar hemorrhages were associated with cerebrospinal fluid (CSF) loss during AH and ATL. There was no mortality in the TLE group, and 0.75 % permanent mild deficits. Seizure outcome did not differ from the rest of the group (82.5 % satisfactory seizure control). In contrast, all intraaxial hematomas after tumor surgery (N = 4, incidence 1.9 %) were located in or adjacent to the resection cavity. Prognosis was much worse with parenchymal hemorrhages after tumor surgery: three of four patients died, one survived with a severe hemiparesis, only two patients with extraaxial hematomas (incidence 1 %) had a complete recovery. The 3 % incidence of symptomatic hemorrhages was only insignificantly lower compared to the TLE group, patients with tumor surgery were older than TLE patients (49 versus 33 years), and in five of six patients only incomplete tumor resection was achieved. Although associated with a low permanent morbidity, features of postoperative hemorrhages after TLE surgery are characteristically different to complications after surgery for other indications, which has to be kept in mind for patient counseling and obtaining informed consent.

Insular involvement in temporal lobe epilepsy (TLE) has gradually been recognized since the widespread use of stereoelectroencephalography (SEEG). However, the correlation between insular involvement and failed temporal lobe surgery remains unclear. In this study, we analyzed the surgical outcomes of TLE patients who underwent temporal and insular SEEG recordings and explored the predictors of failed anterior temporal lobectomy (ATL) in these patients with temporal seizures.Forty-one patients who underwent ATL for drug-resistant TLE were examined using temporal and insular SEEG recordings. The clinical characteristics, SEEG data, and postoperative seizure outcomes of these patients were analyzed, and multivariate analysis was used to identify the predictors of surgical outcome.In this series, the ictal temporal discharges invaded the insula in 39 (95.1%) patients. Twenty-three (56.1%) patients were seizure-free (Engel class I) after ATL with at least 1 year follow-up. Only temporal-insular spreading time (TIST) was an independent predictor of postoperative seizure-free outcomes (P = .035). By creating receiver operating characteristic curves for TIST, 400 milliseconds was identified as the cutoff for classification. All patients were classified into 2 groups (TIST ≤ 400 milliseconds and TIST > 400 milliseconds) based on the cutoff value; the difference in seizure-free rates between the 2 groups was significant (P = .001).The very early insular involvement in TLE may be associated with poorer seizure outcomes after ATL. Our findings may be helpful for estimating the appropriate operative procedures and will be valuable for evaluating the prognosis of TLE patients with temporal-insular SEEG recordings and temporal lobectomy.

A lifetime psychiatric history has been reported to be associated with poorer seizure outcome following temporal lobectomy for drug-resistant focal epilepsy, but it remains unclear whether this is confounded by the nature of the epileptogenic pathology. Here we examined this association in a pathologically homogeneous group of patients with mesial temporal sclerosis (MTS). The study population included 72 consecutive patients who underwent a temporal lobectomy for drug resistant temporal lobe epilepsy (TLE) and had histopathologically proven MTS. All patients were assessed preoperatively by a neuropsychiatrist. Chi-square analysis was undertaken to look for demographic, clinical, psychiatric, or neurologic factors associated with seizure outcome at 1 year. The relationship between having a psychiatric disorder and seizure outcome was examined by generating Kaplan-Meier curves and comparing between groups the log rank test as well as generating Cox regression models to estimate hazard ratios. There were no significant associations between postsurgery seizure outcome and a current or lifetime history of any psychiatric disorder. A history of psychiatric disorder, in particular depression and psychosis, is not associated with a poorer surgical outcome in patients with MTS. These findings have implications for the clinical management of patients under consideration for temporal lobectomy.

Patient Historical Risk Factors Associated with Seizure Outcome After Surgery for Drug-Resistant Nonlesional Temporal Lobe Epilepsy

Preoperative sensory aura predicts risk for seizure in temporal lobe epilepsy surgery

Temporal lobe epilepsy (TLE) is the most common form of focal epilepsy, and about two-thirds of patients with drug-resistant TLE are surgical candidates. While many studies suggest better postoperative outcomes in children subjected to various types of surgery, there is limited data comparing adults and children who have undergone the same procedure over the same time period. This study aimed to compare long-term seizure outcomes and identify prognostic factors in pediatric (defined as children less than or equal to 12 years) and adult patients undergoing TLE surgery at a high-volume epilepsy center in South India. The study cohort comprised 684 consecutive patients (127 children, 557 adults) who underwent standard anterior temporal lobectomy. All underwent presurgical evaluation including video EEG, neuroimaging, and surgical decision was made in a multidisciplinary meet. Seizure freedom was defined as "absence of seizures or auras regardless of antiepileptic drug use," which was the primary outcome. The predictors determining outcome in both age groups were also analyzed. Logistic regression identified the predictors, and Kaplan-Meier curves assessed long-term seizure-free survival. Children had significantly shorter epilepsy duration pre-surgery (8.38 versus 19.2 years, p < .0001) and significantly better seizure outcome (57.4% vs. 45.6%, p = .0165). Kaplan-Meier analysis revealed longer median seizure-free survival in children (120 months) than adults (72 months, p = .027). In adults, predictors of poor outcome included auditory aura, behavioral arrest, spike-wave discharges during ictal onset, and bitemporal IEDs. Febrile seizures predicted a favorable outcome in children and adults. In children, neoplasia as a substrate was protective, while psychiatric co-morbidity and multiple auras predicted seizure recurrence. Children benefit more from TLE surgery than adults, due to earlier intervention and shorter duration of seizures. The principle of "time is brain" holds true in epilepsy; prolonged duration of uncontrolled seizures fosters network expansion, highlighting the need for "early surgical referral" and "catching them young."

Because temporal lobe epilepsy (TLE) can impair theory of mind (ToM), we examined the effects of anterior temporal lobectomy (ATL) by comparing the preoperative to postoperative ToM course with that of other cognitive functions characteristically impaired in TLE. Eighty-five patients with left (n = 39) or right (n = 46) drug-resistant TLE and an age at epilepsy onset of >12 (n = 54) or ≤12 years (n = 31) were evaluated before and 1 year after surgery; 40 healthy controls were assessed at baseline. The participants' recognition and comprehension of faux pas (FPs) or correct rejection of nonexistent FPs was assessed using the Faux Pas task; and their language, memory, and planning were, respectively, assessed using the Boston Naming, Short Story, and Tower of London tests. Baseline ToM was impaired in the patients with left or right TLE in comparison with the controls, and significantly influenced by education and age at seizure onset, with more severe deficits being observed in those with less education and an age at onset of ≤12 years. After ATL, their recognition and comprehension of FPs was unchanged, whereas the rejection of nonexistent FPs improved in the patients with early seizure onset. Education, preoperative ToM, postoperative executive function, and fluid intelligence and the number of antiepileptic drugs predicted postoperative ToM. Postoperative naming and episodic memory were associated with ATL laterality and education, and planning was associated with age at seizure onset and chronological age. After ATL, the components of ToM may be unchanged or slightly improved depending on cognitive reserve and age at seizure onset, thus suggesting that ATL does not further aggravate the deficits caused by TLE. Moreover, the course of ToM is distinct from that of other cognitive functions. These findings expand the spectrum of the cognitive phenotypes associated with TLE and ATL, and offer potential elements for individual prognoses.