Epilepsy surgery in patients with normal or nonfocal MRI scans: integrative strategies offer long-term seizure relief

PURPOSE: Excisional surgery achieves seizure freedom in a large proportion of children with intractable lesional epilepsy, but the outcome for children without a focal lesion on MRI is less clear. We report the outcome of a cohort predominantly of children with nonlesional intractable partial epilepsy undergoing resective surgery. METHODS: We studied 102 patients with nonlesional intractable partial epilepsy who underwent excisional surgery. The epileptogenic region was identified by integrating clinical exam and video-EEG data complemented by ictal SPECT (n = 40), PET (n = 10), extraoperative subdural monitoring (n = 80), and electrocorticography (n = 22). All patients had follow-up greater than 2 years, 76 patients had 5-year follow-up, and 43 patients had 10-year follow-up. RESULTS: A total of 66 resections were unilobar; 36 were multilobar. One patient died of causes unrelated to seizures or surgery. At 2-year follow-up, 44 of 101 patients were seizure-free, 15 experienced >90% reduction, 17 had >50% reduction, and 25 were unchanged. At 5-year follow-up, 35 of 76 patients were seizure-free, 12 experienced >90% reduction, 12 had >50% reduction, and 17 were unchanged. At 10-year follow-up, 16 of 43 patients were seizure-free, 13 experienced >90% reduction, 7 had >50% reduction, and 7 were unchanged. Outcomes correlated with the presence of convergent focal interictal spikes (p < 0.005) on the scalp EEG and completeness of resection (p < 0.0005). CONCLUSIONS: Our findings demonstrate that excisional surgery is successful in the majority of children with nonlesional partial epilepsy. A multimodal integrative approach can minimize the size of resection and alleviate the need for invasive EEG monitoring. Focal interictal spikes and completeness of resection predict good outcome. The benefits of surgery are long-lasting.     

Resection of Frontal Encephalomalacias for Intractable Epilepsy: Outcome and Prognostic Factors

Summary: Purpose: Because focal encephalomalacia is an important cause of medically intractable partial epilepsy and few studies have evaluated the efficacy and the safety of resecting focal encephalomalacias to improve seizure control, we studied a cohort of 17 consecutive patients who underwent resection of encephalomalacias in the frontal lobes as a treatment of their intractable epilepsy. Methods: We evaluated several factors for their value in predicting postsurgical seizure control. Pre- and postsurgical magnetic resonance imaging (MRI) scans were reviewed independently by 2 blinded investigators. Results: At a median of 3 years of follow-up (range 0.6–7.5 years), 12 patients (70%) were seizure-free or had only rare seizures. The presence of a focal fast frequency discharge (focal ictal β pattern) at the beginning of seizures on scalp EEG was predictive of seizure-free outcome (p = 0.017), even among patients who had complete resection of their encephalomalacias (p = 0.016). There was no significant differences in outcome with regard to age at the time of the injury that caused encephalomalacia, interval between injury and onset of seizures, duration of presurgical seizure history, presurgical seizure frequency, age at surgery, or the completeness of encephalomalacia resection. The analysis regarding completeness of encephalomalacia resection almost reached significance, suggesting that it may also be an important predictive factor (p = 0.051). Conclusions: We conclude that surgery is a very effective treatment for intractable frontal lobe epilepsy (FLE) secondary to encephalomalacias. Patients are more likely to become seizure-free if they have a focal ictal β discharge on their scalp EEG. Complete resection of the encephalomalacia should be attempted, since our results suggest that this may be a favorable predictive factor. Moreover, the operative strategy for our patients entailed, whenever possible, complete resection of the encephalomalacias and of the adjacent electrophysiologically abnormal tissues.     

难治性外伤性癫痫的外科治疗42例分析

目的 探讨难治性外伤件癫痫的外科治疗方法及治疗效果。方法 回顾性分析42例接受外科手术并得到有效随访2年以上的外伤性癫痫病人的手术方式、手术效果。所有病人均行术前MRI检查，存偶极子定位下行手术治疗。结果 术后癫痫发作完全消失或仅有先兆31例，极少发作（≤3次／年）3例，手术效果满意率81．0％；发作明显改善（减少≥75％）5例，无明显改善（减少＜75％）3例，手术效果不满意率19．5％术后平均随访25.5月。结论 对难治性外伤件癫痫行偶极子定位下外科于术治疗可获得满意效果。     

Hippocampal or neocortical lesions on magnetic resonance imaging do not necessarily indicate site of ictal onsets in partial epilepsy

Advances in neuroimaging techniques, particularly high-resolution magnetic resonance imaging (MRI), have proved invaluable in identifying structural brain lesions in patients with epilepsy. The assumption that such focal lesions invariably predict the site of seizure origin may not be correct, however. We report a series of 20 adults with medically intractable partial epilepsy, where high-resolution brain MRI disclosed a unilateral, focal, hippocampal, or neocortical lesion as the only abnormality in each case; nevertheless, based on electroencephalographic (EEG) recordings, ictal onsets arose from a completely different location than that of the MRI lesion. All patients underwent epilepsy surgery, with the operations based on ictal EEG findings, and all were followed at least 2 years after the resection. After the most recent follow-up examination, 50% (10/20) of the patients were completely seizure-free, 35% (7/20) had at least a 75% reduction in the number of seizures, and 15% (3/20) had less than a 75% reduction in the number of seizures. We conclude that the identification of a focal, structural, hippocampal, or neocortical lesion on brain MRI is not always indicative of the site of seizure origin in partial epilepsy. Furthermore, in cases of discordance between MRI and EEG data, a good outcome after epilepsy surgery is possible if EEG ictal onsets are definitive.     

Surgical outcome and predictive factors in adult patients with intractable epilepsy and focal cortical dysplasia

OBJECTIVES: To determine the surgical outcome and prognostic factors in adult patients with intractable epilepsy and focal cortical dysplasia (FCD). MATERIALS AND METHODS: We retrospectively studied the operative outcome in 21 consecutive adult patients with FCD who underwent surgical treatment for intractable partial epilepsy. RESULTS: The mean age at surgery was 32.7 years (range, 18-58 years). The median post-operative follow-up was 2.5 years. The FCD was extratemporal in 11 patients, involved the temporal lobe in 10 patients, and was multilobar in eight patients. Eleven patients (52%) were rendered seizure-free, four patients (19%) had >95% reduction in seizures, and two patients (10%) had an 80-94% reduction in seizures. A seizure-free outcome was associated with shorter duration of epilepsy (P = 0.02). CONCLUSION: Adult patients with FCD may be candidates for surgical treatment of intractable partial epilepsy. Most individuals have neocortical, extrahippocampal seizures and approximately 50% of patients are rendered seizure-free.     

Seizure outcome after surgery for epilepsy due to focal cortical dysplastic lesions.

Neocortical development is a highly complex process encompassing cellular proliferation, neuronal migration and cortical organization. At any time this process can be interrupted or modified by genetic or acquired factors causing malformations of cortical development (MCD). Epileptic seizures are the most common type of clinical manifestation, besides developmental delay and focal neurological deficits. Seizures due to MCD are frequently pharmacoresistant, especially those associated to focal cortical dysplasia (FCD). Surgical therapy results have been reported since 1971, however, currently available data from surgical series are still limited, mainly due to small number of patients, distinct selection of candidates and surgical strategies, variable pathological diagnosis and inadequate follow-up. This study addresses the possibilities of seizure relief following resection of focal cortical dysplasia, and the impact of presurgical evaluation, extent of resection and pathological findings on surgical outcome. We included 41 patients, 22 adults and 19 children and adolescents, with medically intractable seizures operated on from 1996 to 2002. All were submitted to standardized presurgical evaluation including high-resolution MRI, Video-EEG monitoring and ictal SPECT. Post-surgical seizure outcome was classified according to Engel's schema. Univariate and multivariate analysis were performed. Fifteen patients had temporal and 26 extratemporal epilepsies. Of the total 26 patients (63.4%) reached seizure-free status post-operatively. There was no correlation between outcome and age at surgery, duration of epilepsy, frequency of seizures, and pathological findings. There was, however, a clear correlation with topography of FCD (temporal versus extratemporal) and regional ictal EEG onset, on univariate as well as multivariate analysis.     

大脑半球切除术治疗半侧巨脑症合并顽固性癫痫

目的　总结半侧巨脑症合并顽固性癫痫病人行大脑半球切除术治疗的临床效果。方法　经MRI检查确诊 10例半侧巨脑症病人 ,伴有顽固性癫痫 ,头颅增大不对称 ,颅腔扩大 ,偏瘫 ,不同程度的精神运动发育迟缓 ,都是一侧大脑半球损害。行病侧大脑半球切除术。结果　 7例癫痫发作完全控制 (70 % ) ,3例基本控制 (30 % )。精神运动症状 ,语言 ,肢体运动及行为均有较明显改善。结论　大脑半球切除术治疗半侧巨脑症合并顽固性癫痫 ,可以解除患者的癫痫发作及长期药物依赖 ,改善脑的功能 ,是一种有效的治疗方法     

Subdural strip electrode monitoring and surgical decision making in refractory epilepsy: validity and prognostic value of noninvasive localizing data

We analyzed the rationale for invasive monitoring in refractory epilepsy. In 54 selected patients, video/scalp-EEG was insufficient for seizure focus localization. Therefore, bilateral subdural electrodes were implanted for ictal recording. In 40 (74.1%) of 54 patients, ictal electrocorticography (ECoG) localized a seizure focus amenable to resection. Fourteen (25.9%) of 54 patients, had multiple foci or primary generalized seizures. Among 36 patients who had focal resection with at least 1-year follow-up, 32 (88.9%) are either seizure-free or significantly improved. Magnetic resonance imaging (MRI) and interictal single photon emission computed tomography (SPECT) had the highest sensitivity and specificity (80.0 and 81.8%, respectively) and the greatest diagnostic value (64.0 and 77.8%, respectively) for seizure focus localization. Independent of electrophysiologic data, MRI determination of focal abnormality was prognostic for seizure-free outcome. Concordance of one or more noninvasive techniques with ictal ECoG seizure focus localization was statistically significant in predicting seizure-free outcome. Although interest in noninvasive selection of candidates for focal resection is increasing, there remains a role for invasive monitoring of epileptogenic foci that are difficult to localize. Our study should improve selection of patients with refractory epilepsy for focal resection when ictal ECoG is used in conjunction with noninvasive data for surgical decision making.     

Predicting outcome following reoperation for medically intractable epilepsy.

The purpose of this study was to determine predictors of probable outcome following reoperation for medically intractable partial epilepsy. We reviewed outcome at least 1 year after reoperation in 21 patients with intractable seizures, for whom an earlier operation had failed. We examined age of onset of epilepsy, duration of seizures, gender, details of the history and clinical examination, pre-operative magnetic resonance (MRI) findings, electroencephalographic (EEG) studies obtained before and after the failed surgery, presence or absence of lateralizing neuro-psychological deficits, sites of operation and pathology of resected tissue to identify the factors associated with outcome. We found two factors that were significantly related to outcome: (1) no individual with a history of central nervous system (CNS) infection which predated the onset of epilepsy had a seizure-free outcome after reoperation (P = 0.04). (2) Reoperations that extended previous resections, based on new ictal EEG recordings that were concordant with both EEG ictal onsets and MRI findings obtained before the first, failed surgery resulted in a seizure-free outcome or >95% reduction in seizures for 100% (7/7) of such patients. This compares to 29% (4/14) of the remaining individuals without such concordance who had a similar outcome (P = 0.009). Site of operation (temporal or extratemporal) did not, in and of itself, predict outcome. A portion of patients who fail surgery for intractable partial seizures will achieve significant improvement following reoperation. Furthermore, we may be able to identify those individuals most likely to have an excellent result from a second operation.     

Discontinuation of antiepileptic drugs after successful epilepsy surgery

OBJECTIVE: To evaluate the frequency and risk factors for seizure recurrence subsequent to antiepileptic drug (AED) withdrawal in patients who underwent surgical treatment for intractable partial epilepsy and were rendered seizure-free. METHODS: The outcome of discontinuation of AED medication was studied retrospectively in 210 consecutive patients who were rendered seizure-free after epilepsy surgery performed between 1989 and 1993. RESULTS: Medical therapy was reduced in 96 patients and discontinued in 84 patients. The seizure recurrence rate after complete AED withdrawal was 14% and 36% at 2 and 5 years. In contrast, only 3% and 7% of the 30 patients who did not alter AED treatment after surgery had recurrent seizures in the same time intervals. After AED discontinuation, seizures tended to recur more often in patients with normal preoperative MRI studies compared with those with focal pathology. However, this difference did not reach significance. Intraoperative electrocorticography, extent of surgical resection, postoperative EEG, and seizure-free duration after surgery were not predictive of seizure outcome after AED withdrawal. CONCLUSIONS: AED withdrawal was associated with seizure recurrence in a significant portion of patients rendered seizure-free by epilepsy surgery. Patients with a normal preoperative MRI study showed a tendency for higher seizure recurrence, whereas the duration of seizure-free postoperative AED treatment interval did not significantly influence the seizure recurrence rate. These results will prove useful in counseling patients about discontinuing AED treatment after successful epilepsy surgery.     

Surgical Treatment of Extratemporal Epilepsy: Clinical, Radiologic, and Histopathologic Findings in 60 Patients

Summary: Purpose and Methods: The aim of this study was to analyze clinical, radiologic, and histopathologic findings in 60 consecutive patients with medically intractable extratemporal epilepsy who were operated on between November 1987 and May 1993.
Results: Histologically, there were distinct structural abnormalities in 50 (83%) of the surgical specimens. Signal abnormalities on magnetic resonance imaging (MRI) were present in all patients with neoplastic lesions (n = 17) and in 94% of patients with nonneoplastic focal lesions (n = 32). Overall, structural abnormalities were detected by MRI in 47 (96%) of 49 patients with focal lesions. During a mean follow-up of 4 years, 30 (54%) patients remained completely seizure free, 11 (20%) had ≤2 seizures per year, seven (12%) showed a seizure reduction of ≥75%, and eight (14%) had <75% reduction in seizure frequency. The fraction of seizure-free patients was 12 (80%) of 15 in patients with neoplastic lesions, 16 (52%) of 31 in patients with nonneoplastic focal lesions, and two (20%) of 10 for those without histopathologic abnormalities. The differences in seizure outcome between patients with and without focal lesions were statistically significant (p < 0.05), if seizure-free outcome was compared with persistent seizures.
Conclusions: Focal lesions and particularly neoplasms are associated with improved postoperative seizure control compared with patients without histopathologic abnormalities. We advise caution in considering surgery to treat extratemporal epilepsy in patients who have normal MRI scans, because the outcome with the approach described in this study is poor in such cases.     

Acute postoperative seizures after frontal lobe cortical resection for intractable partial epilepsy

PURPOSE: To evaluate the incidence and prognostic importance of acute postoperative seizures (APOSs) occurring in the first week after a focal corticectomy in patients with partial epilepsy of frontal lobe origin. METHODS: We retrospectively evaluated 65 patients who underwent a frontal lobe cortical resection for intractable partial epilepsy between April 1987 and December 2000. All patients were followed up for a minimum of 1 year after surgery. RESULTS: APOSs occurred in 17 (26%) patients. None of the following factors was shown to be significantly associated with the occurrence of APOSs: gender, duration of epilepsy, etiology for seizure disorder, use of subdural or depth electrodes, surgical pathology, or postoperative risk factor for seizures. Patients with APOSs were older at seizure onset and at the time of surgery (p = 0.003 and p = 0.05, respectively). At last follow-up, patients who had APOSs had a seizure-free outcome similar to that of individuals without APOSs (47.1% vs. 50.0%; p = 0.77). Patients with APOSs appeared less likely to have a favorable outcome [i.e., fewer than three seizures per year and >95% decrease in seizure activity (58.8 vs. 70.8%; p = 0.35)]. This result may not have reached statistical significance because of the sample size. No evidence suggested that precipitating factors or the timing of APOSs was an important prognostic factor. CONCLUSIONS: The presence of APOSs after frontal lobe surgery for intractable epilepsy does not preclude a significant reduction in seizure tendency. These findings may be useful in counseling patients who undergo surgical treatment for frontal lobe epilepsy.     

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.     

Seizure outcome after epilepsy surgery in children and adolescents

Few epilepsy surgery outcome data are available from series of pediatric patients. We studied seizure outcome in 136 pediatric patients who had surgery for intractable epilepsy at The Cleveland Clinic between January 1990 and June 1996, with a postoperative follow-up of 1 to 7.5 years (mean, 3.6 years). Sixty-two children (3 months to 12 years old at time of surgery) were compared with 74 adolescents (13–20 years old). Extratemporal or multilobar resections and hemispherectomies were similarly frequent among children (50%) and adolescents (44%), but these procedures strongly predominated in infancy (90% of patients 0–2 years of age). The remaining patients had temporal resection. Cortical dysplasia and low-grade tumor were the most common causes and hippocampal sclerosis was rare. Seizure-free outcome was achieved for 69% of adolescents, 68% of children, and 60% of the infant subgroup, overall; for 23 (74%) of 31 children and 33 (80%) of 41 adolescents after temporal resection; for 11 (58%) of 19 children and 15 (52%) of 29 adolescents after extratemporal or multilobar resection; and for 8 (67%) of 12 children and 3 (75%) of 4 adolescents after functional hemispherectomy. Seizure-free outcome was more frequent after temporal resection (56 of 72, 78%) than after extratemporal or multilobar resection (26 of 48, 54%; 41 of 48 with a focal lesion on magnetic resonance imaging), and among patients with tumor (36 of 44, 82%) versus cortical dysplasia (16 of 31, 52%). The frequency of seizure-free outcome after epilepsy surgery was similar for infants, children, and adolescents, and comparable with results from adult series. Most patients in each age, surgery type, and causal group were free from seizures after surgery. These results suggest that children should be considered for surgical evaluation at whatever age they manifest with severe, intractable, disabling localization-related epilepsy.     

Extratemporal resection for childhood epilepsy

There have been relatively few studies reporting the safety, efficacy, and outcome in children undergoing extratemporal resection for epilepsy. We reviewed the pediatric cases of extratemporal resection for intractable epilepsy performed by the Comprehensive Epilepsy Program at the University of Alberta Hospitals between 1988-1998. Thirty-five patients were studied, 14 male and 21 female. The age at operation ranged from 6 months to 16 years. The operations included frontal excisions (12), parietal (8), occipital (4), hemispherectomies or multilobar resections (10), and one removal of a hypothalamic hamartoma. The pathology at surgery included patients with focal cortical dysplasia (8), brain tumors (6), neurocutaneous syndrome (7), Rasmussen's encephalitis (2), porencephalic cysts (4), hypothalamic hamartoma (1), and nonspecific gliosis (6). Twenty-four of 35 patients (68.5%) had an Engel Class I outcome after surgery and an additional six patients (11%) had a significant decrease in seizure frequency (Engel Class III). Complications were observed in two patients (5%) and there were no deaths. Extratemporal resection is a safe and effective treatment for children with intractable epilepsy. Overall, 68% of patients were seizure-free after surgery, although outcome may be dependent on site and pathology. A wide range of developmental pathology was observed including focal cortical dysplasia, brain tumors, and lesions with neurocutaneous syndromes. Many families reported improvement in behavior and psychosocial function after surgery.     

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.     

Resective surgery for intractable focal epilepsy in patients with low IQ: predictors for seizure control and outcome with respect to seizures and neuropsychological and psychosocial functioning

PURPOSE: To investigate possible predictive factors for seizure control in a group of children and adults with low IQs (IQ, < or =70) who underwent resective surgery for intractable focal epilepsy and to study outcome with respect to seizures and neuropsychological functioning. We also studied psychosocial outcome in the adult patients. METHODS: Thirty-one patients (eight children younger than 18 years) with a Wechsler Full Scale IQ of 70 or less underwent comprehensive neuropsychological assessments before and 2 years after surgery. Adults also completed the Washington Psychosocial Seizure Inventory (WPSI). Univariate analyses were used to identify variables differentiating between patients who became seizure free and those who did not. Pre- and postoperative test results were compared by t test for dependent samples. RESULTS: Forty-eight percent of the patients became seizure free, 52% of those with temporal lobe resection and 38% of those with extratemporal resection. Only one variable was predictive for seizure outcome: duration of epilepsy. In one third of the patients, who had the shortest duration of epilepsy (<12 years), 80% became seizure free. Significant improvement was seen regarding vocational adjustment in adults (WPSI). Seizure-free adults improved their Full Scale IQ scores. No cognitive changes were found in seizure-free children or in patients who did not become seizure free. CONCLUSIONS: A good seizure outcome was obtained after resective surgery in patients with intractable focal epilepsy and low IQ, provided that treatment was done relatively shortly after onset of epilepsy. No adverse effects were seen on cognitive and psychosocial functioning.     

Interictal, unifocal spikes in refractory extratemporal epilepsy predict ictal origin and postsurgical outcome.

OBJECTIVES: To evaluate the significance of exclusively unifocal, unilateral, interictal epileptiform patterns on scalp electroencephalography (EEG) in surgical candidates with medically intractable extratemporal epilepsy. METHODS: We reviewed 126 patients with refractory extratemporal partial seizures who underwent epilepsy surgery at our center. All were followed for at least 2 years after resections. Surgery was based on ictal EEG recordings. We examined ictal onsets and surgical outcome in subjects whose preoperative, interictal scalp EEGs during long-term monitoring (LTM) demonstrated only unilateral, well-defined focal discharges, and outcome in patients whose interictal EEGs during LTM showed bilateral, non-localized, or multifocal epileptiform patterns. RESULTS: We found that 26 subjects exhibited only unilateral, unifocal, interictal epileptiform patterns. In all 26 cases (100%) clinical seizures arose from the regions expected by the interictal findings (P<0.0001, Sign test). At last follow-up 77% (20/26) of these patients were seizure-free, while 23% (6/26) had >75% reduction in seizures. This compares to the remaining patients, of whom 34% (34/100) were seizure-free, 41% (41/100) had >75% reduction in seizures, and 25% (25/100) had <75% reduction in seizures (P=0.0001, Fisher's Exact test). CONCLUSIONS: Strictly unifocal, interictal epileptiform patterns on scalp EEG, though seen in a minority of subjects, may be an important, independent factor in evaluating subjects with intractable extratemporal, localization-related epilepsy for surgical therapy. This finding is highly predictive of both ictal onsets and successful postsurgical outcome.     

Low-Grade Glial Neoplasms and Intractable Partial Epilepsy: Efficacy of Surgical Treatment

Summary: We performed a retrospective study of 51 consecutive patients who underwent operation for intractable partial epilepsy related to low-grade intracerebral neoplasms between 1984 and 1990. All patients had medically refractory partial seizures and a mass lesion identified on neuroimaging studies. Lesionectomy was performed on 17 patients, and 34 had lesion resection and corticectomy. Mean postoperative follow-up was 4.4 years (range 2–8 years). Sixty-six percent of patients were seizure-free, and 88% experienced a significant reduction in seizure frequency. In 16 patients (31%), antiepileptic drugs (AEDs) were successfully discontinued. Twenty-five of 31 (81%) eligible patients obtained a driver's license after successful operation. Patients with complete tumor resection and no interictal epileptiform activity on postoperative EEG studies had the best operative outcome. Epilepsy surgery can result in long-term improvement in seizure control and quality of life (QOL) in selected patients with intractable tumor-related epilepsy. Our results should be useful to clinicians considering treatment options for patients with intractable seizures related to low-grade intracerebral neoplasms.     

Focal ictal beta discharge on scalp EEG predicts excellent outcome of frontal lobe epilepsy surgery

PURPOSE: To determine whether a focal beta-frequency discharge at seizure onset on scalp EEG predicts outcome of frontal lobe epilepsy (FLE) surgery. METHODS: We identified 54 consecutive patients with intractable FLE who underwent epilepsy surgery between December 1987 and December 1996. A blind review of EEGs and magnetic resonance images (MRIs) was performed. Lesional epilepsy is defined as presence of an underlying structural abnormality on MRI. RESULTS: Overall, 28 (52%) patients were seizure free, with a mean follow-up of 46.5 months. Presence of a focal beta-frequency discharge at seizure onset on scalp EEG predicted seizure-free outcome in lesional (p = 0.02) and non-lesional (p = 0.01) epilepsy patients. At least 90% of patients who had either lesional or non-lesional epilepsy were seizure free if scalp EEG revealed a focal beta discharge at ictal onset. Moreover, logistic regression analysis showed that focal ictal beta pattern and completeness of lesion resection were independently predictive of seizure-free outcome. Ictal onset with lateralized EEG activity of any kind and postresection electrocorticographic spikes did not predict surgical outcome (p > 0.05). CONCLUSIONS: Only about 25% of FLE surgical patients have a focal beta-frequency discharge at seizure onset on scalp EEG. However, its presence is highly predictive of excellent postsurgical seizure control in either lesional or non-lesional FLE surgical patients.