Candidates For Anterior Temporal Lobectomy Research Articles

Anterior temporal lobectomy: A cross-sectional observational study of potential surgical candidates at a single institute.

Background: Epilepsy is a common neurological disorder, associated with serious cognitive, physical, and psychosocial burdens. Mesial temporal lobe epilepsy (mTLE) is the commonest form of focal epilepsy. The aim of this study was to establish the incidence of patients with electroencephalographic epileptiform discharges consistent with mTLE attending a tertiary hospital in South Africa, and determine whether these patients may be candidates for anterior temporal lobectomy.Methods: This was a cross-sectional observational study of all patients receiving scalp electroencephalograms (EEG) performed at the Groote Schuur Hospital Neurophysiology laboratory during the period January 1, 2017–December 31, 2019. Where magnetic resonance imaging (MRI) brain scans had been performed, these were assessed for corroborative evidence of mTLE.Results: Over the 3-year period, 4 342 EEGs were assessed. A total of 411 (11%) showed epileptiform discharges consistent with all epilepsy types. Of these, 327 (69%) were of focal onset and 108 (33% of all focal onset epilepsies) were consistent with mTLE. Of the patients with electroencephalographic features of mTLE, only 27 (25%) had had MRI brain scans performed according to an epilepsy surgery protocol. None of these patients had been considered for surgery.Conclusion: Surgery, especially anterior temporal lobectomy, is widely acknowledged to be an efficacious and cost-effective intervention in patients with drug-resistant mTLE. The findings of our study suggest that patients with mTLE in our setting are under-investigated for potential surgery; and that it is under-utilized. These findings are in line with similar studies in both well-resourced and resource-constrained countries. Our study also highlights the utility of EEG as a practical screening tool to identify potential surgical candidates, as well as the establishment of an EEG and MRI database to assist in recognizing these patients.

Auras as a prognostic factor in anterior temporal lobe resections for mesial temporal sclerosis.

Anterior temporal lobectomy for mesial temporal sclerosis (MTS) is a very effective measure for the control of seizures, and the probability of becoming seizure-free is approximately 70-90%. However, 30% of patients still experience seizures after surgery. An aura is a subjective ictal phenomenon that may precede an observable seizure. However, there are few studies on the prognostic factor aura although, being the initial symptoms of epileptic seizures, many types of auras have significant localizing or lateralizing value. This study hypothesized that the type of pre-operative aura may predict the post-surgical outcome in patients with medically refractory temporal lobe epilepsy due to MTS. Of 1214 patients evaluated for surgery in the Epilepsy Center of Faculdade de Medicina de São Jose do Rio Preto (FAMERP), a tertiary Brazilian epilepsy center, 400 underwent anterior temporal lobectomy (ATL) for MTS. The number and type of auras were analyzed and compared with the Engel classification for outcome. Analyzing the patients by the type of aura, those who had extratemporal auras had the worst post-surgical result according to the Engel classification. Although mesial auras are apparently a good prognostic factor, patients without aura also had a worse prognosis. There were no differences between simple and multiple auras. To identify the most appropriate candidates for ATL, it is very important to consider the favorable prognostic factors for counseling patients in daily practice. Patients with symptoms and clinical signs that suggest extratemporal involvement may have unfavorable outcomes.

Outcome after temporal lobectomy in patients with medically-refractory mesial temporal epilepsy in Iran.

Epilepsy surgery has been proved to be feasible and cost-effective in developing countries. In the current paper, we discussed the outcome of patients with mesial temporal lobe epilepsy (MTLE) and medically-refractory seizures who had surgery at our center in Shiraz, Iran. Patients aged 18 years and older with refractory MTLE and mesial temporal sclerosis operated at Namazee Hospital, Shiraz University of Medical Sciences, Shiraz, Iran from May 2009 through December 2011 were enrolled. Presurgical evaluation included clinical history, neurological examination, 2-hour video-EEG recording, and 1.5-T MRI. All patients were submitted to standard temporal lobectomy at the side determined by MRI and video-EEG. Twenty-two patients (12 women and 10 men) underwent surgery between May 2009 and December 2011. All patients were followed postoperatively for at least 12 months (mean=24.8±7.7 months; minimum=12 months; maximum=36 months). At the last follow-up visit, 18 patients (81.8%) had a good outcome (15 patients [68.2%] had Engel class 1 and three others had Engel class 2). The total cost of presurgical evaluation and epilepsy surgery at our center was less than $500. Resources are limited for the vast majority of medically-refractory patients with epilepsy who live in the developing countries. However, it is feasible to select good surgical candidates for anterior temporal lobectomy relying on the clinical history and examination, MRI and interictal EEG. Broader application of epilepsy surgery should be encouraged in countries with limited financial resources.

Preoperative IQ predicts seizure outcomes after anterior temporal lobectomy

Purpose IQ tests are frequently used in the preoperative neuropsychological assessment of candidates for anterior temporal lobectomy (ATL). We reviewed IQ test results and surgery outcomes to evaluate the roles of IQ tests in the preoperative work-up. Methods A total of 205 adult patients who had undergone ATL and whose seizure outcomes were followed for 2 years after surgery were included. The short form WAIS-R was used to estimate intelligence. Multiple linear regression and logistic regression analyses were used to examine the variables for IQ and seizure outcomes. Results Education, duration of epilepsy and gender were factors that accounted for 24.6% of the variance in the full-scale IQ (FSIQ) scores. The verbal IQ and performance IQ discrepancies at various magnitudes could not lateralize the seizure foci. Freedom of seizure was noted in 128 (62.4%) of the patients. Seizure outcomes, however, correlated with the preoperative FSIQ. After adjustment for variables that affect seizure outcomes, the FSIQ was an independent predictor of postoperative seizure outcomes (OR 1.04, 95% CI 1.01–1.06, p = 0.003). Of patients who had FSIQ lower than 70, 50% became free from seizures by 2 years after surgery. Conclusions In our study, IQ tests were unable to lateralize seizure foci but may serve as an independent predictor of postoperative seizure outcomes. Since a longer duration of epilepsy had deleterious effects on intelligence, earlier surgical intervention might better preserve neuropsychological function and, consequently, allow better seizure control after ATL. Nonetheless, patients with lower IQ scores could still benefit from ATL.

PET imaging of brain 5-HT1A receptors in the preoperative evaluation of temporal lobe epilepsy

[(18)F]MPPF PET has previously been used to identify the epileptic lobe in temporal lobe epilepsy (TLE) patients at the group level. This study aims to validate the visual analysis of [(18)F]MPPF PET in the assessment of individual TLE patients for their suitability to undergo temporal lobe resection. Forty-two patients suffering from TLE and 18 control subjects matched for age and gender were prospectively enrolled for [(18)F]MPPF PET. Four subtypes were defined according to the presurgical evaluation: mesio-TLE (MTLE, 32 patients), temporal neocortical epilepsy (NC, five patients), temporo-perisylvian epilepsy (T+, three patients) and temporal epilepsy without further information (t, two patients). Parametric binding potential (BP(ND)) images were obtained using a simplified reference tissue model. Three examiners, who were blinded to other data, visually interpreted each scan and delineated areas of decreased [(18)F]MPPF BP(ND). Statistical parametric mapping (SPM) analysis of MPPF BP(ND) images was also performed. Visual analysis showed a low rate of disagreement between the three examiners (7%). PET scans were considered normal in four patients (9.5%). In the remaining 38 patients (90.5%), areas of focal BP(ND) decrease were identified. A specific pattern was encountered in the MTLE subgroup, consisting of a BP(ND) decrease involving hippocampus, amygdala and temporal pole altogether. Combining the results from the presurgical investigations and the surgical outcome, we estimated that the area of BP(ND) decrease coincided with the epileptogenic zone in 40% of patients in the MTLE subgroup and 33% in the other TLE subtypes. This relatively low precision was due to 47% of patients who showed BP(ND) decreases in the insula ipsilateral to the epileptogenic lobe. The SPM analysis had much lower sensitivity (67%) to detect BP(ND) decreases in the epileptogenic temporal lobe, but revealed areas of increased BP(ND) outside the epileptogenic zone and bitemporal BP(ND) decreases of undetermined clinical significance, which were undetectable by visual analysis, in 29% of patients. In conclusion, visual analysis of [(18)F]MPPF BP(ND) images helps in the correct identification of the epileptogenic temporal lobe in all patients showing BP(ND) decreases, with a false negative rate inferior to 10% and no false positives in control subjects. All TLE patients with [(18)F]MPPF BP(ND) decreases involving hippocampus, amygdala and temporal pole together, with or without extension to the ipsilateral insula, were good candidates for anterior temporal lobectomy. All these patients became seizure free after surgery, even when the clinical presentation was not that of a typical MTLE, or when MRI failed to detect hippocampal atrophy.

Predictive value of Wada memory scores on postoperative learning and memory abilities in patients with intractable epilepsy

Surgery for refractory epilepsy often bestows significant relief but may cause memory impairment. The risk of postoperative memory loss can be determined by the intracarotid amobarbital procedure, or the Wada test. Chemical inactivation of the hemisphere on the side of the lesion is usually performed first, followed by inactivation of the contralateral hemisphere. Patients who demonstrate adequate memory capacity of the contralateral hemisphere following deactivation of the ipsilateral hemisphere are considered good candidates for anterior temporal lobectomy. Evidence for the contribution of deactivating the contralateral healthy hemisphere remains inconclusive. The authors analyzed results in 32 patients with intractable epilepsy who had undergone a bilateral Wada test followed by an anterior temporal lobectomy and in whom the findings of both pre- and postsurgical neuropsychological evaluations were available. The Wada memory scores were correlated with the difference in scores between pre- and postsurgical standardized memory test scores. Analyses revealed no significant relationship between the Wada memory scores in the contralateral hemisphere and postsurgical changes in memory abilities. There was, however, a significant negative correlation between the Wada memory score in the ipsilateral hemisphere and postsurgical memory changes, particularly in patients with right hemisphere epileptogenic lesions (p = 0.0007). The results of this study are discussed vis-à-vis two theories of hippocampal function, and the authors stress the importance of the functional status of the surgical hemisphere in the prediction of postsurgical memory changes.

Indication for anterior temporal lobectomy in patients with temporal lobe epilepsy and psychopathology.

The chronicity and severity of epilepsy, as well as the presence of temporal lobe toci, appear to correlate with psychopathology. A high prevalence of psychopathology has been reported among patients who are candidates for anterior temporal lobectomy (ATL). A review of the literature indicates that episodic psychosis may diminish when patients become free of seizures after surgery and that chronic psychosis neither improves notr worsens after ATL. If this is the case, patients with episodic psychosis may benefit from ATL. Patients with chronic psychosis may benefit if they become free from seizures after the operation, even if the psychosis persists. Case reports of maladjustment to seizure-free life after surgery, and de novo psychopathology, underline the importance of preoperative psychiatric evaluation and postoperative psychiatric intervention in patients undergoing epilepsy surgery. Although there is a need for each epilepsy center to state its policy with regard to patients with psychopathology who undergo epilepsy surgery, it would be unwise to make a decision on whether to reject a patient simply on the grounds of psychosis. A detailed psychiatric evaluation of each individual patient is required.

A cost-effectiveness analysis of anterior temporal lobectomy for intractable temporal lobe epilepsy.

Patients with medically intractable temporal lobe epilepsy are potential candidates for anterior temporal lobectomy (ATL), in which epileptogenic temporal lobe tissue is localized and surgically removed. This surgical approach can eliminate or drastically reduce seizures in the majority of patients. The authors used a decision-analysis model to examine the cost-effectiveness of a surgical evaluation and treatment protocol for medically intractable temporal lobe epilepsy. This model compared a cohort treated with the new protocol with a continuation of their immediate preoperative medical management and projected these differences over the patient's lifetime. The Markov model incorporated postoperative seizure status, patient quality of life, death from surgical and natural causes, discounting, and the direct medical costs associated with outpatient evaluation, hospitalization, surgery, antiepileptic drugs, and lifetime outpatient treatment. The intent-to-treat analysis included patients who underwent evaluation but were not eligible for ATL. Sensitivity analyses were also performed on the variables in the model. Data from the baseline model indicated that evaluation for ATL provided an average of 1.1 additional quality-adjusted life years (QALYs) compared with continued medical management, at an additional cost of $29,800. Combining the clinical and economic outcomes yielded a cost-effectiveness ratio of $27,200 per QALY. This value is comparable to other accepted medical or surgical interventions, such as total knee arthroplasty ($16,700/QALY) or coronary artery balloon angioplasty ($40,800/QALY). Sensitivity analyses demonstrate that the results are critically dependent on postoperative seizure status and improvement in quality of life. Although further work is necessary to quantify the improvement in quality of life after epilepsy surgery better, the present data indicate that ATL for treatment of intractable temporal lobe epilepsy is a cost-effective use of medical resources.

Effect of Wada memory stimulus type in discriminating lateralized temporal lobe impairment.

To examine the effects of memory stimulus type on Wada memory performance. Ninety-six patients (left, 47; right, 49) from four epilepsy centers who were candidates for anterior temporal lobectomy (ATL) and who have subsequently undergone surgery were studied. Patients with atypical cerebral language lateralization or with evidence on magnetic resonance imaging (MRI) to suggest a lesion other than hippocampal sclerosis were excluded. Wada memory performance was obtained by using both real objects and line drawings as memory stimuli. Wada memory laterality scores with either real objects or line drawings as memory stimuli discriminated left from right-ATL groups. However, objects were superior to line drawings in making this differentiation. Further, objects were superior to line drawings in individual patient classification of candidates for left ATL, with no difference in the classification rates using either objects or line drawings in candidates for right ATL. Type of memory stimuli is an important factor affecting memory results during the Wada test.

Epileptogenic paroxysms: modern approaches and clinical correlations.

Epileptogenic paroxysms were studied in patients whose attacks were verified during prolonged recordings on the closed-circuit television-electroencephalogram (CCTV-EEG). Three types of complex partial seizures and four subvarieties of absence seizures were observed. All patients with complex partial seizures showed interictal spikes. Focal, low-voltage 8- to 30 Hz rhythms were most common during the onset of partial seizures in 64 patients, whereas diffuse spike-wave complexes appeared most often during generalized seizures in 26 patients. Relating the exact onset of clinical attacks on the videotape to depth electrographic events defined the local or diffuse origin of seizures in candidates for anterior temporal lobectomy.