Temporal lobe epilepsy: analysis of failures and the role of reoperation.

PURPOSE: To analyze failures and reoperations in temporal lobe epilepsy (TLE), and compare these patients with those seizure-free, and to determine any significant differences between the groups. METHODS: A total of 262 patients with TLE, treated surgically between 1984 and 2002, were followed at 3, 6 and 12 months and yearly thereafter. Sixty-five percent became seizure-free (class I), 19% had rare seizures (class II), and 16% continued to have seizures (classes III and IV). Patients in classes III and IV underwent re-evaluation, and were compared with seizure-free patients. RESULTS: Analysis of failures (n = 41): 12% had febrile seizures (FS), 29% head trauma, 7% encephalitis, 52% abnormal imaging, 34% bitemporal spiking, and 20% posterior temporal localization. Post-surgical MRI (available in 30 of 41 patients) showed residual posterior mesial temporal structures (PMTS) in 86.6%, PMTS and posterior temporal lesions (PTLs) in 6.6%, and PTLs in another 6.6%. Twenty-one had reoperation, 14 had resection of the PMTS, five of the PMTS and basal posterior temporal cortex, and two of the PMTS, and PTLs. There was no surgical mortality or morbidity; 57% became seizure-free and 24% had rare seizures. Seizure-free patients (n = 170): 45% had FS, 12% head trauma and 70% abnormal imaging studies. CONCLUSION: When compared with seizure-free patients, patients who failed TLE surgery were less likely to have a history of FS and abnormal imaging, and more likely to have a history of head trauma, encephalitis and posterior temporal localization, suggesting larger epileptogenic zones. Following reoperation, 57% became seizure-free. Predictors of a good outcome after reoperation were anterior temporal localization and abnormal imaging studies.

Temporal lobe epilepsy: analysis of patients with dual pathology.

OBJECTIVES: To determine the frequency and types of dual pathology in patients with temporal lobe epilepsy (TLE) and to analyze the clinical manifestations and surgical outcome. MATERIAL AND METHODS: A total of 240 patients with TLE underwent temporal resections following a comprehensive pre-surgical evaluation. Thirty-seven (15.4%) of these had hippocampal sclerosis (HS) or temporal lobe gliosis in association with another lesion (dual pathology). RESULTS: Eighteen of 37 patients with dual pathology had heterotopia of the temporal lobe, nine had cortical dysplasia, four had cavernous angiomas or arteriovenous malformations, one had a dysembryoplastic neuroepithelial tumor, one had a contusion and four patients had cerebral infarctions in childhood. 68.5% had abnormal head magnetic resonance imagings, 91.3% had abnormal positron emission tomography scans, and 96% had abnormal ictal SPECT. The intracarotid amobarbital procedure (IAP) showed impaired memory of the epileptogenic side in 72% of the patients. Twenty patients had left and 17 had right-sided en bloc temporal resections, including the lesion and mesial temporal structures. Twenty-six (70.2%) became seizure-free, eight (21.6%) had rare seizures, two (5.4%) had worthwhile seizure reduction and one (2.7%) had no improvement (range of follow-up 1-16 years, mean = 7.4 years). CONCLUSIONS: 15.4% had dual pathology. The dual pathology was almost exclusively seen in patients whose lesions were congenital, or occurred early in life, suggesting that the hippocampus is more vulnerable and more readily develops HS in early childhood. Resections, including the lateral and mesial temporal structures led to a favorable outcome with no mortality and little morbidity.

Temporal lobe epilepsy surgery: outcome, complications, and late mortality rate in 215 patients.

PURPOSE: We studied the surgical outcome, complications, and the late mortality rate in a large group of patients with medically refractory temporal lobe epilepsy (TLE). METHODS: Two-hundred fifteen patients with TLE were treated surgically between 1984 and 1999 after a comprehensive presurgical evaluation. Patients were followed up at 6 weeks, 3-6 months, and yearly thereafter. In addition, questionnaires were sent on the anniversary of their surgery. Surgical outcome (Engel's classification), complication rate, and factors contributing to late mortality were analyzed. Standardized mortality ratios (SMRs) were calculated. RESULTS: There was no surgical mortality. Two (0.9%) had mild hemiparesis, one (0.4%) had a hemianopia, seven (3.2%) had transient cranial nerve palsies, and eight (3.7%) had transient postoperative language difficulties. One hundred forty-eight (69%) became seizure free, 43 (20%) had rare seizures, 14 (6.5%) had worthwhile seizure reduction, and 10 (4.6%) had no improvement (follow-up, 1-15 years). Three (2%) of 148 seizure-free patients died during follow-up, compared with eight (11.9%) of 67 not seizure-free patients. The mean duration of epilepsy before surgery for the surviving patients was 17.8 years, and for those patients who died, 25.9 years (p < 0.05). Six (5.7%) of 104 patients with right-sided resections died during follow-up, compared with five (4.5%) of 111 with left-sided resections. CONCLUSIONS: Eighty-nine percent of patients became seizure free or had rare seizures, with low morbidity, and no surgical mortality. The late mortality occurred predominantly in patients with persistent seizures (SMR, 7.4). Those patients who died had a longer duration of epilepsy before surgery. In contrast, among those patients who became seizure free, the mortality rate was much lower, and similar to the general population of Indiana (SMR, 1.7).

Tumor-related epilepsy in children.

A 10-year retrospective review of 15 children with cerebral tumors and seizures was conducted to study the factors responsible for delay in the diagnosis of tumors and to assess outcome following surgery. Mean duration of seizures prior to surgery was 37 months. Ninety-three percent had no focal neurologic deficits. Head computed tomography was abnormal in 64%, whereas magnetic resonance imaging was abnormal in all patients. Electroencephalography showed focal abnormalities ipsilateral to the tumor in 73%. There was no surgical mortality. Eighty percent were seizure free or had rare seizures following surgery. Factors contributing to a delayed diagnosis of the brain tumor included a nonfocal neurologic examination and delay in obtaining an appropriate neuroimaging study. We believe that head magnetic resonance imaging should be the investigation of choice in partial epilepsies.

Focal functional deficits in temporal lobe epilepsy on PET scans and the intracarotid amobarbital procedure: comparison of patients with unitemporal epilepsy with those requiring intracranial recordings.

PURPOSE: To analyze the relationship between the intracarotid amobarbital procedure (IAP) and positron emission tomography (PET) and study the lateralizing value of these tests in patients with unitemporal epilepsy and those requiring intracranial recordings. METHODS: We compared 51 patients with unitemporal epilepsy (group1) with 26 patients in whom surface recordings failed to reveal a distinct unitemporal focus, necessitating invasive recordings (group 2). RESULTS: The brain magnetic resonance imaging (MRI) scans for group 1 showed mesial temporal sclerosis in 70.5% of the patients. PET showed unilateral temporal hypometabolism in 88%. In addition, 74.5% of the patients in group 1 had impaired memory on the epileptogenic side on the IAP, and 89.4% of those patients also had ipsilateral temporal hypometabolism on PET scans. All the group 1 patients underwent temporal resections. The pathologic examination showed hippocampal sclerosis in 72% of the patients. Eighty percent of group 1 patients became seizure free, and 16% had rare seizures (follow-up, 2-7 years). MRIs for group 2 showed mesial temporal sclerosis in 31% of the patients; PET scans showed temporal hypometabolism in 39%. The IAP was lateralized in 47.8%. Sixty-nine percent had temporal lobe resections. The pathologic examination showed hippocampal sclerosis in 44% of the patients. Forty-four percent of group 2 patients became seizure free, and 27.7% had rare seizures (follow-up, 2-8 years). CONCLUSIONS: Ninety-six percent of the patients with unitemporal foci had focal functional deficits on the epileptogenic side on 18-fluorodeoxyglucose-(FDG) PET scans, the IAP, or both. The results of the FDG-PET were predictive of impaired memory on the IAP. Memory impairment contralateral to the temporal hypometabolism found on the PET scans was never seen. These patients had an excellent outcome. In contrast, <50% of the patients requiring intracranial recordings had focal functional deficits, suggesting that more a diffuse pathology may account for their less favorable outcome.

Health-related quality of life outcome in medically refractory epilepsy treated with anterior temporal lobectomy.

PURPOSE: A prospective study to investigate health-related quality of life (HRQOL) outcome in patients with temporal lobe epilepsy treated with anterior temporal lobectomy (ATL). METHODS: The majority of the patients with medically refractory focal epilepsy had Quality of Life in Epilepsy-89 (QOLIE-89) assessment at the time of prolonged video/EEG monitoring as part of their presurgical evaluation. Thirty-seven patients who were not treated surgically constituted the control group, and 53 patients who underwent ATL made up the surgery group. Both control and surgery groups had HRQOL assessment repeated at approximately 1-and 2-year intervals. Repeated measures analysis of variance (ANOVA) was used to test for differences between the two groups. RESULTS: For the overall score and almost every scale, the surgery group had a higher baseline mean than the control group. Because of this baseline difference, change scores were used in further analysis. The overall score and 10 of 17 scales in QOLIE-89 showed significant HRQOL improvement after ATL, and the improvement was significant relative to score changes of the nonsurgical comparison group. Scores improved in overall QOL, emotional well-being, attention/concentration, language, social isolation, health perception, role limitations-physical, work/drive/social, health discouragement, and seizure worry. For the first five scales, there was group-time interaction; the improvement was significantly more on the 2-year than on the 1-year follow-up. When the surgery patients were divided into four categories (class IA-, completely seizure free; class IA+, seizure free with aura; class II, rare seizures; class III, worthwhile improvement in seizure control; and class IV, no improvement), the improved HRQOL in the surgery group was almost entirely contributed by the class IA- outcome patients who were totally seizure free. The class IA+ patients with continuing aurae and class II/III/IV patients had no significant improvement in their overall HRQOL scores at 1-or 2-year follow-up. CONCLUSIONS: Overall score and 10 of the 17 scales of QOLIE-89 significantly improved in patients with medically refractory temporal lobe epilepsy after ATL. For some scales, there was delay in the improvement to manifest. The HRQOL improvement was related to achieving an entirely seizure-free status (i.e., no seizures or aurae postoperatively).

Longitudinal follow-up in 145 patients with medically refractory temporal lobe epilepsy treated surgically between 1984 and 1995.

PURPOSE: There are few studies of prolonged longitudinal follow-up after temporal resections. METHODS: We analyzed 145 consecutive patients with temporal lobe epilepsy treated surgically. Patients had a comprehensive presurgical evaluation, including video-EEG, psychometric testing, magnetic resonance imaging (MRI), single-photon emission computed tomography (SPECT), intracarotid amobarbital procedure (IAP), and recently, volumetric head MRIs and F-fluorodeoxyglucose-positron emission tomography (FDG-PET) scans. Most had en bloc temporal resections, and a few had lesionectomies and resection of the epileptogenic zone. There was no surgical mortality. Longitudinal follow-up data of the seizure outcome were analyzed by actuarial analysis. Patients were followed up at 6 weeks, 3 months, 6 months, and then on a yearly basis. The mean follow-up was 5.6 years. RESULTS: Sixty-six percent were seizure free at 1 year, 63% at 2 years, 60% at 5 years, and 55% at 10 years follow-up. Moreover, 85%, became seizure free for > or =2 at the time of last follow-up or had rare seizures. Patients who were seizure free for 1 and 2 years after surgery, had an 83% and 92% probability, respectively, of remaining seizure free at the time of last follow-up. Ninety-one percent of patients with small tumors and cavernous angiomas became seizure free compared with 69% of patients with hippocampal sclerosis. CONCLUSIONS: Actuarial analysis showed that the long-term surgical outcome of temporal lobe epilepsy remains favorable. Follow-up at 1 and 2 years is highly predictive of the long-term outcome. Patients with discrete lesions had the best outcome. Most of the patients with late recurrences had hippocampal sclerosis or temporal lobe gliosis. Some patients with postoperative seizures eventually became seizure free, reflecting the running-down phenomenon.

Presurgical evaluation and surgical outcome of temporal lobe epilepsy.

The authors analyzed 22 patients younger than 18 years of age with temporal lobe epilepsy (TLE) treated surgically. Patients underwent a comprehensive presurgical evaluation, including video-electroencephalogram. Fifty-five percent had a history of febrile seizures. Eighty-two percent had auraes and most exhibited oroalimentary and gestural automatisms. Contralateral dystonic posturing was present in 36% and postictal dysphasia in 54% of patients with left-sided resections. Cranial magnetic resonance imaging (MRI) was abnormal in 59% of patients. MRI revealed changes consistent with mesial temporal sclerosis in 8 (47%) of 17 patients without lesions. Fluorodeoxyglucose-positron emission tomography (PET) scans revealed ipsilateral temporal hypometabolism (PET-TH) in 12 (85.7%) of 14 patients. The intracarotid amobarbital procedure revealed impaired memory of the epileptogenic side in 59% of patients. Seventeen patients underwent en-bloc resections and five lesionectomies and resection of the epileptogenic area. There was no surgical morbidity or mortality. Forty-three percent had hippocampal sclerosis, 28.5% gliosis, 14% low-grade tumors, 9.5% cavernous angiomas, and 5% had no pathologic findings. Follow-up (6 months to 12 years) was available for 21 patients; 76% became seizure free, 19% had rare seizures, and 5% had a worthwhile improvement. TLE can be safely treated surgically in younger patients with excellent results. The clinical manifestations were similar to adult patients. PET-TH was present even at a younger age, suggesting that the focal functional deficits appear early in patients with medically refractory TLE, which may help in the early identification of these patients.

FDG-PET and MRI in temporal lobe epilepsy: relationship to febrile seizures, hippocampal sclerosis and outcome.

OBJECTIVE: To correlate the volumetric head magnetic resonance imaging (MRI) and fluorodeoxyglucose-positron emission tomography (FDG-PET) scan findings with the history, intracarotid amobarbital procedure, pathology, and outcome in patients with medically refractory temporal lobe epilepsy. MATERIAL AND METHODS: Thirty-eight patients with temporal lobe epilepsy treated surgically following a comprehensive presurgical evaluation. Follow-up ranged from 12 to 44 months. RESULTS: Volumetric MRI showed ipsilateral hippocampal atrophy in 29 (76%), and PET scan showed ipsilateral temporal hypometabolism (PET-TH) in 31 (81.5%) of patients. Eighty-three percent of those patients with hippocampal sclerosis on MRI (MRI-HS) had ipsilateral PET-TH. Sixty-six percent of patients with MRI-HS had a history of prolonged febrile convulsions or a childhood febrile illness accompanied by convulsions, and 77% of patients with MRI-HS had pathologically proven hippocampal sclerosis (HS). Ninety percent became seizure free or had rare seizures. CONCLUSION: FDG-PET scans and head MRIs were complementary; 95% of patients had either MRI-HS or temporal hypometabolism. MRI-HS correlated with a history of febrile seizures and pathologically demonstrated hippocampal sclerosis. Ninety-three percent of patients had focal functional deficits on the epileptogenic side. Concordance between PET temporal hypometabolism and MRI-HS correlated with better outcome.

Comparative study of interictal PET and ictal SPECT in complex partial seizures.

OBJECTIVE: To compare the sensitivity of ictal 99mTc-HMPAO single photon emission computed tomography (SPECT) with interictal 18F-fluoro-deoxyglucose positron emission tomography (PET) in localization of the epileptogenic focus in patients with medically intractable complex partial seizures (MI-CPS). MATERIAL AND METHODS: Retrospective analysis was performed on patients with MI-CPS who underwent anterior temporal lobectomy from January 1993 onwards when PET became available to us for clinical studies at the Indiana University Medical Center. There were 38 female and 29 male patients (total = 67) with MI-CPS, 10 to 55.5 years of age (mean 31) and duration of their epilepsy from 1-46 years (mean 21). Interictal PET was evaluated for evidence of focal hypometabolism and ictal SPECT for focal perfusion abnormality (hyperperfusion or hypoperfusion) by visual analysis. RESULTS: Both ictal SPECT and interictal FDG-PET studies were obtained in 36 patients with MI-CPS. PET showed definite hypometabolism in 30 and questionable hypometabolism in an additional two patients. Ictal SPECT correctly localized the seizure focus in 27 patients by demonstrating ictal hyperperfusion whereas in one the hyperperfusion was falsely localized. In an additional seven patients the ictal SPECT provided probable localization by demonstrating ictal hypoperfusion in the appropriate temporal lobe. The sensitivity of ictal SPECT and interictal PET was 34/36 and 32/36, respectively, the difference was not statistically significant (chi 2y = 0.18, DF = 1, P = 0.67). In six of the 36 patients the two tests were complementary to each other in providing localizing information. CONCLUSION: Ictal SPECT and interictal PET are equally sensitive and reliable techniques in localizing the epileptogenic focus in patients with MI-CPS. They play a critical role in providing localization in MRI negative patients allowing surgical resection to be undertaken in many without additional invasive electrographic monitoring.

Diagnostic utility of video EEG monitoring in paroxysmal events.

OBJECTIVES: A retrospective study was conducted to evaluate clinical usefulness of video EEG monitoring in patients with suspected epileptic seizures. MATERIAL AND METHODS: A total of 444 patients who had diagnostic video EEG from January 1989 to December 1992 were studied after excluding those with known medically refractory focal epilepsy undergoing presurgical evaluation. Most were outpatients and had video EEG monitoring during normal working hours over 1-5 days. RESULTS: The procedure had a success rate of 73%; characteristic events were captured and categorized in 53% of the patients. Patients with an event frequency of at least one per week or those who had events characterized by motor manifestations showed a higher yield. Thirty-two percent of the patients had psychogenic seizures. Thirty-four percent of the patients had either epileptic seizures recorded during the study or showed clear-cut interictal epileptiform abnormalities providing strong evidence of underlying epileptic process. CONCLUSION: In patients with frequent paroxysmal events, a video EEG study provides diagnostically critical information. It can be performed usually as an outpatient investigation.

The running down phenomenon in temporal lobe epilepsy.

We compared 100 patients with temporal lobe epilepsy, who exhibited the running down phenomenon following temporal resections, with two groups of patients: 100 patients who became seizure-free, and 100 patients who continued to have frequent seizures following temporal resection. We found a significant correlation between prognosis and the size of the epileptogenic area as defined; patients with smaller epileptogenic areas had the best prognosis (seizure-free group). Patients exhibiting the running down phenomenon had intermediate size epileptogenic areas, while those patients who continued to have seizures had the largest epileptogenic areas often involving the lateral temporal and posterior temporal cortex. Other factors predictive of good outcome were: a history of febrile seizures, predominantly unilateral interictal spiking, anterior temporal localization, extent of resection of the mesial temporal structures, surgery under the age of 30 years, and the absence of habitual seizures in the immediate postoperative period. Patients with history of head trauma, encephalitis, posterior temporal localization and bitemporal spiking had a worse outcome. The frequency and types of aurae, and laterality of resection did not correlate with outcome.

Tumoural parietal lobe epilepsy. Clinical manifestations and outcome in 34 patients treated between 1934 and 1988.

Between 1934 and 1988, 34 patients with tumoural parietal lobe epilepsy were treated surgically at the Montreal Neurological Institute (MNI). Fifteen had right-sided and 16 left-sided resections. The remaining three patients had biopsies only. Follow-up ranging from 1 to 40 years (mean 12.3 years) was available for 28 patients. Seventy-five percent (21 out of 28) became seizure free or had rare seizures. Permanent post-operative sensory deficits were described in 12% of patients. An aura was described by 79%. 62% had somatosensory symptoms, contralateral to the epileptogenic region in all but one. Visual illusions (12%), aphasia (9%) and disturbances of body image (6%), were much less common at the beginning of the attacks. Intra-operative cortical stimulation reproduced the habitual aurae in 10 out of 25 (40%) of the patients. The clinical manifestations suggested different spread patterns: 21% had tonic posturing of the extremities, 82% focal clonic activity, 15% head deviation, 9% automatisms and 6% difficulty speaking. Eleven (32%) had Todd's paralysis and 18% postictal dysphasia. Almost half the patients had impaired two-point discrimination in contralateral fingers; two of these also had impaired stereognosis, but only one had astereognosis without coexisting primary cortical sensory deficit. Review of this, now historical, series shows that parietal lobe tumours can be resected with good control of previously intractable seizures. Such an approach is preferable to postponing resection until the lesion is shown to increase in volume.

Parietal lobe epilepsy. Clinical manifestations and outcome in 82 patients treated surgically between 1929 and 1988.

We report the clinical manifestations and outcome of 82 patients with nontumoural parietal lobe epilepsy treated surgically at the Montreal Neurological Institute between 1929 and 1988. Patients with extensive resections extending outside the parietal lobe were excluded. Ninety-four percent exhibited aurae: the most common were somatosensory, described by 52 patients; 13 of these also described pain. Other aurae included disturbances of body image, visual illusions, vertiginous sensations and aphasia or dysphasia. A few patients exhibited complex visual or auditory hallucinations and elementary visual hallucinations. Intraoperative cortical stimulation reproduced the habitual aurae in 44 patients. Often the clinical manifestations indicated ictal spread to the frontal, supplementary motor area, or temporo-limbic areas: 28% of patients exhibited tonic posturing of the extremities, 57% unilateral clonic activity, 17% oral or gestural automatisms and 4% complex automatisms. Sixty-one percent of patients with tonic posturing had epileptogenic zones which included the superior parietal lobe, and in 79% of patients with automatisms the epileptogenic zones extended to the inferior parietal lobe, suggesting different spread patterns. Forty-three patients underwent right, and 39 left parietal corticectomies. Postoperative sensory deficits were seen only when the corticectomy extended into the post-central gyrus. Early in the series extensive nondominant inferior parietal resections led to disturbances of body image in a few patients. Follow-up ranging from 2 to 50 years was available for 79 patients. Sixty-five percent had a complete or nearly complete cessation of seizures. Those patients with no post-resection electrocorticographic epileptiform discharges had a more favourable outcome.

Frontal lobe seizures: electroclinical syndromes.

To define further the electroclinical manifestations of frontal lobe epilepsy (FLE), we studied 150 seizures manifested by 24 patients; 18 patients had subdural electrode arrays (SEA). The findings in these patients clearly overlapped presumably reflecting the interconnections between functionally related frontal zones; yet the manner in which the symptoms clustered and the sequence in which they occurred generally indicated the anatomic site of the epileptogenic zone. We divided the patients into three major groups: (a) those with supplementary motor seizures, (b) those with focal motor seizures, and (c) those with complex partial seizures (CPS, psychomotor seizures). Supplementary motor seizures began with tonic posturing of the extremities. Focal motor seizures generally began with conscious contralateral version or unilateral clonic focal motor activity; tonic posturing was noted only late in the seizure. CPS (psychomotor) began with unresponsiveness at onset, followed by staring or unconscious contraversion. We compared frontal lobe seizures with temporal lobe seizures reported previously; oral-alimentary automatisms, repetitive hand movements, or looking around, were more common in temporal lobe seizures, whereas tonic posturing and bicycling movements were more common in frontal lobe psychomotor seizures.

Clinical characteristics and predictive factors in 98 patients with complex partial seizures treated with temporal resection.

OBJECTIVE: To analyze the preoperative and operative factors predictive of outcome in patients undergoing surgery for temporal lobe epilepsy. DESIGN: From 1984 to 1992, 98 patients with medically refractory temporal lobe epilepsy underwent surgery. Evaluation included the following: video electroencephalography (13 patients had intracranial recordings), head magnetic resonance imaging, interictal and ictal single photon emission computed tomography, psychometric testing, and Wada testing. Seizure-free groups and non-seizure-free groups were analyzed. Follow-up of 1 year to 8 years was available for 89 patients (mean, 3.2 years). SETTING: Indiana University Epilepsy Surgery Program, Indianapolis. OUTCOME: Sixty percent (53/89) were seizure free, 16% (14/89) had rare seizures, 13% (12/89) had worthwhile improvement, and 11% (10/89) showed no improvement. Forty-two percent of seizure-free patients had a history of febrile seizures compared with 5% of non-seizure-free patients. Ictal single photon emission computed tomography showed increased flow on the side of seizure onset in 86% of seizure-free patients compared with 62% of non-seizure-free patients. Ninety-seven percent of seizure-free patients had a pathologic diagnosis; mesial temporal structures were identified in 61%. Only 64% of non-seizure-free patients had a pathologic diagnosis, and mesial temporal structures were identified in only 36% of non-seizure-free patients. CONCLUSIONS: Eighty-nine percent (79/89) of our patients benefited from surgery. The following factors were predictive of good outcome: a history of febrile seizures; ictal single photon emission computed tomography showing increased blood flow ipsilateral to the epileptogenic zone; a pathologic diagnosis; and the presence of mesial temporal structures in the resected tissue.

Reevaluation of surgical failures and the role of reoperation in 39 patients with frontal lobe epilepsy.

Between 1929 and 1980, 284 patients with refractory nontumoral frontal lobe epilepsy (FLE) underwent operation at the Montreal Neurological Institute (MNI). We studied 39 patients (14%) who required reoperation. Mean age at the time of first operation was 18 years and at reoperation was 22 years. Clinical manifestations were similar to those of patients with "a pure culture of frontal lobe epilepsy" as reported by Rasmussen in 1983. At the time of first operation, large epileptogenic zones were noted in most patients. Resection was confined to the frontal lobe. Continuing seizure activity was due to residual areas of epileptogenesis, and reoperation with more extensive resection of cortex increased the number of seizure-free patients. Twenty-six patients underwent further frontal resection, and in 13 surgical removal was extended to the temporal lobe. Residual electrocorticographic (ECoG) spiking was documented in 15 of 23 (65%) of the reoperated patients. Thirty-five patients were followed for periods ranging from 4 to 46 years. One fifth became seizure-free, and 31% had significant seizure reduction. Thus, half of these patients had a good result. Patients with residual postexcision ECoG spiking had poor outcomes and evidence of large epileptogenic zones. None of the patients who underwent frontotemporal resections became seizure-free. Reoperation should be considered if initial resection does not lead to a satisfactory result and may convert an initial failure into a good surgical result.

Ictal brain imaging in presurgical evaluation of patients with medically intractable complex partial seizures.

At the Indiana University Medical Center, 99 patients with medically intractable complex partial seizures (MI-CPS) had presurgical evaluation with subsequent anterior temporal lobectomy. The majority of the patients had single photon emission tomography (SPECT) performed interictally as well as during an actual epileptic seizure (ictal scan). Decreased regional cerebral perfusion (rCP) was seen in 54/94 (57%) of the interictal scans corresponding to the eventual site of the surgery. However, ictal scans provided a higher yield; increased rCP in the temporal lobe during an actual seizure was observed in 60/82 (73%) concordant to the side of surgery. SPECT is a useful, noninvasive method of localizing the epileptiform focus in patients with MI-CPS considered for resective surgery. Both interictal and ictal SPECT need to be performed; combined interictal hypoperfusion and ictal hyperperfusion in the same focal area are unique to epileptogenic lesions. Ictal SPECT studies can be performed in the majority of patients during the period of continuous video/EEG monitoring with only a little additional effort. Combining the results of functional brain imaging (interictal and ictal SPECT, PET) with clinical semiology of seizures, surface and sphenoidal EEG, magnetic resonance imaging and other non-invasive tests, anterior temporal lobectomy can be recommended in approximately two-thirds of the patients without resorting to potentially dangerous intracranial EEG monitoring.