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.     

Smoldering encephalitis in children

Five children presented with focal seizures and neurological deficits that progressed over a span of months to years. Three had temporal lobectomy to control seizures, one underwent temporal lobe biopsy, and the fifth, who suffered from immunodeficiency, had an occipital lobectomy to remove a mass. Two of the children expired. Neuropathological findings in all five children were consistent with a persistent active "viral" encephalitis. No infectious agent was identified. None of the children had the usual systemic signs of encephalitis and all lacked an inflammatory response in their cerebrospinal fluid. We conjecture that this condition may be more frequent than realized. Besides causing intractable focal seizures and hemiparesis, it may account for other poorly understood syndromes of childhood with deteriorating behavior.     

Posterior temporal epilepsy: Electroclinical features

In the course of evaluating children with posterior temporal lobe epilepsy with subdural electrodes, we observed that their seizures commonly arose from basal rather than convexity foci and that they followed a stereotyped clinical sequence. Seizures characteristically began with behavioral arrest that coincided with basal temporal seizure discharges and progressed to motor signs as the seizure activity spread to the ipsilateral cortical convexity. Behavioral automatisms were observed in approximately half the patients, but were never the first or most prominent ictal manifestation. Focal lesions were identified preoperatively in 7 patients. We performed tailored temporal lobe resections in 14 patients, 10 (71%) of whom were seizure free (N = 9) or had occasional auras (N = 1) at a mean follow-up of 2 years. These findings suggest that in childhood, posterior temporal seizures frequently arise from basal cortex and have a consistent and recognizable ictal and electrographic semiology. In medically refractory patients, tailored temporal resection is an effective therapy.     

MRI阴性的颞叶癫痫的外科治疗

目的 总结MRI阴性的颞叶癫痫的手术疗效.方法 对2004年4月至2009年12月间行前颞叶切除的并且MRI为阴性的32例颞叶癫痫患者的资料进行回顾性分析.包括术前检查、手术方式、术后病理及手术疗效.结果 Engel Ⅰ级为21例,占66％;EngelⅡ级为4例,占12％,EngelⅢ～Ⅳ级为7例,占22％,其中头皮视频脑电图痫波位于一侧颞叶的手术效果较好,86％可达到Engel Ⅰ级.结论 对MRI阴性的颞叶癫痫术前评估要更加全面,如检查结果趋于一致,手术效果良好,特别是癫痫样放电起源于一侧颞叶的手术效果更佳.     

Epilepsy surgery in children with gliomatosis cerebri

PURPOSE: Gliomatosis cerebri (GC) is a rare neoplastic disorder that may present as intractable epilepsy during early life. We report our experience regarding the evaluation and the surgical treatment of epilepsy in this population. METHODS: All children evaluated between 1990 and 2006 for surgery of epilepsy (n = 741) with pathologically proven GC were selected. RESULTS: We identified four male children with age at seizure onset ranging from 4 months to 11 years. Two had hemiparesis and one child with infantile spasms was developmentally delayed. Seizures occurred daily (n = 3) or monthly (n = 1). Ictal semiology was consistent with psychomotor seizures (n = 1), partial motor seizures (n = 2), and asymmetric epileptic spasms (n = 1). Surgery was symptomatic and aimed at debulking and controlling the epilepsy. Procedure was individually tailored based on the presurgical evaluation. Brain MRI revealed widespread hemispheric involvement (n = 3) or infiltration of the temporal lobe and basal ganglia (n = 1). Two patients were initially misdiagnosed as hemispheric cortical dysplasia and hemimegalencephaly. Scalp EEG was nonlocalizing in two cases, showed a right temporal focus in one case, and was not performed in one case. Interictal SPECT in one patient revealed widespread hemispheric hypoperfusion. Three cases were resected under ECoG guidance after a mean delay of 11 months after seizure onset. Following functional hemispherectomy (n = 1) or focal cortical resection (n = 2), all children were alive and seizure free with a mean follow-up of 48 months (2-5 years). No unexpected complication was reported. One nonoperated case was alive but still seizing after 15 months follow-up. Chemotherapy was associated in three cases. CONCLUSIONS: GC is a rare cause of medically resistant epilepsy that may present in early life. The lack of a discrete lesion may lead to diagnostic uncertainty, especially in infancy. Epilepsy surgery is an effective therapy that can improve quality of life.     

Temporal lobectomy in patients with bitemporal epilepsy defined by depth electroencephalography

Patient selection for temporal lobectomy was reviewed for 23 patients with seizures that arose independently from each temporal lobe as detected by depth electroencephalography (EEG). Although neuropsychological testing, interictal EEG findings, imaging studies, and subclinical seizures were also considered, all patients offered temporal lobectomy had (1) at least 50% of the clinical seizures originating from the lobe to be resected, (2) adequate contralateral memory on testing with amobarbital, and (3) no clear evidence of an extratemporal focus. Eleven patients underwent temporal lobectomy. Pathological findings were considered positive in all nine specimens reviewed. Nine patients had no seizures, one had greater than 75% reduction in seizure frequency, and 1 had 50 to 75% reduction. Pathological features and clinical outcome were similar in the 6 patients with fewer than 80% and the 5 patients with at least 80% of seizures originating from the resected lobe. Thus, having fewer than 80% of seizures originate from one temporal lobe should not be an absolute contraindication for temporal lobectomy.     

Effective Temporal Lobectomy in Childhood Without Invasive EEG

Summary: Temporal lobectomy abolished complex partial seizures (CPSs) in 14 consecutive children (12 years or younger) whose presurgical evaluation included clinical analysis, scalp EEG, and neuroimaging. Seizures of 13 of 14 patients began with a simple partial component whose symptoms were suggestive of limbic system involvement. EEG recorded clinically typical seizures arising from the ultimately operated on temporal lobe in seven (50%) and never falsely lateralized seizure origin. Most active interictal spikes arose from the epileptogenic temporal lobe in 13 (93%) and never falsely lateralized epileptogenesis. Neuroimaging disclosed epileptogenic lesions in all: magnetic resonance imaging (MRI; 11 patients) and computed tomography (CT; three patients). Children may obtain relief from CPSs by temporal lobectomy without invasive electroencephalography.     

Low-dose stereotactic radiosurgery is inadequate for medically intractable mesial temporal lobe epilepsy: a case report.

The successful surgical treatment of medically refractory epilepsy is based on one of three different principles: (1) elimination of the epileptic focus, (2) interruption of the pathways of neural propagation, and (3) increasing the seizure threshold through cerebral lesions or electrical stimulation. Temporal lobe epilepsy, being the most common focal epilepsy, may ultimately require temporal lobectomy. This is a case report of a 36-year-old male with drug-resistant right mesial temporal lobe epilepsy who failed to obtain seizure control after stereotactic radiosurgery to the seizure focus. Complex-partial seizures occurred 6-7 times monthly, and consisted of a loss of awareness followed by involuntary movements of the right arm. EEG/CC TV monitoring indicated a right mesial temporal lobe focus, which was corroborated by decreased uptake in the right temporal lobe by FDG-PET and by MRI findings of right hippocampal sclerosis. Stereotactic radiosurgery was performed with a 4MV linac, utilizing three isocenters with collimator sizes of 10, 10, and 7 mm respectively. A dose of 1500 cGy (max dose 2535 cGy) was delivered in a single fraction to the patient's right amygdala and hippocampus. There were no acute complications. Following radiosurgery the patient's seizures were improved in both frequency and intensity for approximately 3 months. Antiepileptic medications were continued. Thereafter, seizures increased in both frequency and intensity, occurring 10-20 times monthly. At 1 year post radiosurgery, standard right temporal lobectomy including amygdalohippocampectomy was performed with subsequent resolution of complex-partial seizures. Histopathology of the resected temporal lobe revealed hippocampal cell loss and fibrillary astrocytosis, consistent with hippocampal sclerosis. No radiation-induced histopathologic changes were seen. We conclude that low-dose radiosurgery doses temporarily changed the intensity and character of seizure activity, but actually increased seizure activity long-term. If radiosurgery is to be an effective alternative to temporal lobectomy for medically intractable temporal lobe epilepsy, higher radiosurgery doses will be required. The toxicity and efficacy of higher-dose radiosurgery is currently under investigation.     

Somatosensory auras in refractory temporal lobe epilepsy

PURPOSE: To determine the prevalence, manifestations, lateralizing value, and surgical prognostic value of somatosensory auras (SSAs) in patients with refractory temporal lobe epilepsy (TLE). METHODS: Eighty-one consecutive patients undergoing temporal lobectomy for refractory complex-partial seizures were screened for SSAs. The characteristics of the somatosensory phenomena, occurrence of other aura types, seizure semiology, findings of EEG and imaging studies, temporal lobe neuropathology, and postoperative seizure outcome were determined in each patient with SSAs. RESULTS: Nine (11%) of 81 patients with refractory temporal lobe seizures reported distinct SSAs as part of their habitual seizures. The most common manifestation of SSAs was tingling (eight of nine, 89%), but sensory loss (one of nine, 11%) and pain (one of nine, 11%) also were reported. Five patients had unilateral somatosensory symptoms, and four patients had bilateral somatosensory symptoms. Seizure origin was in the contralateral temporal lobe in four (80%) of five patients with unilateral SSAs, including all patients with unilateral SSAs affecting a limb. Partial temporal lobe resection produced complete seizure remission in all nine (100%) patients 1 year after surgery and in seven (78%) of nine patients 2 years after surgery. CONCLUSIONS: SSAs occur more frequently than previously appreciated in patients with refractory temporal lobe seizures and usually manifest as either unilateral or bilateral tingling. In patients with temporal lobe seizures, unilateral SSAs involving a limb suggest a seizure origin in the contralateral temporal lobe. The surgical outcome of TLE patients with SSAs is favorable. Thus the presence of SSAs should not serve as a deterrent to temporal lobe resection in patients with clearly defined TLE.     

Outcome after surgery in patients with refractory temporal lobe epilepsy and normal MRI.

Our purpose is to determine predictors of outcome in patients with refractory temporal lobe epilepsy and normal high resolution magnetic resonance imaging (MRI) who undergo surgical therapy. We identified 23 patients who underwent temporal lobectomy and had normal pre-operative MRI, including surface coil phased array temporal lobe imaging. All were followed at least 2 years after surgery. We graded outcome as seizure-free, > 75% reduction in seizures, or < 75% reduction in seizures. We examined pre-operative interictal and ictal electroencephalographic (EEG) findings, age of onset, gender, duration of epilepsy, risk factors, family history, physical findings, age at operation, side of operation, and pathology of resected tissue in order to determine if any of these factors were associated with outcome. Overall, 48% (11/23) of patients were seizure-free, 39% (9/23) had > 75% reduction in seizures, while 13% (3/23) had < 75% reduction in seizures. Only the EEG findings were useful in predicting outcome. When ictal onsets arose from basal-temporal regions, 61% (11/18) of patients were seizure-free, while none (0/5) were seizure-free when seizures arose from mid-posterior temporal regions (P = 0.04). Interictally, if all epileptiform patterns were localized exclusively to one basal-temporal region, a finding that invariably correlated with ictal onsets, 78% (7/9) of patients were seizure-free, while only 29% (4/14) were seizure-free if discharges were bilateral or multifocal (P = 0.04). We conclude that surgery may be a reasonable treatment for some patients with intractable temporal lobe seizures and normal MRI. The best outcomes occur when seizure onsets and interictal epileptiform patterns are exclusive to one basal-temporal region. Unfavorable outcomes are most likely to occur when ictal origins are from mid-posterior temporal regions and when interictal discharges are bitemporal or multifocal in distribution.