The surgical management of pediatric brain tumors causing epilepsy: consideration of the epileptogenic zone

Objective

Children suffering from epilepsy with suspected low-grade tumors may benefit from a surgical approach that considers the epileptogenic zone, which can be more extensive than the tumor region. This study aimed to determine the prevalence of epilepsy in children undergoing supratentorial tumor resection and the factors predictive of postoperative seizure freedom in children with low-grade tumors.

Methods

Subjects 3 months to 21 years undergoing supratentorial brain tumor resection between 2007 and 2011 were included in this retrospective study. Children with supratentorial, cortically based tumors and a preoperative diagnosis of epilepsy were considered epilepsy surgery candidates. Pre- and postoperative MRI were reviewed and scored for extent of resection, adjacent dysplasia, and remaining abnormal cortex postoperatively.

Results

The prevalence of seizures in all cases of supratentorial tumors was 46/87 (53 %). Eighteen were epilepsy surgery candidates. Eight of 18 (44 %) were seizure-free postoperatively with a mean follow-up of 39 months. Children who were seizure free postoperatively had tried fewer anticonvulsants than those with continued seizures (1.7 v. 2.9, p?=?0.01). Presurgical evaluation was nonstandardized, and a more extensive workup and resection were performed in children who continued to have seizures postoperatively.

Conclusions

All epilepsy surgery candidates had low-grade tumors on histological evaluation, indicating that a surgical approach that takes into consideration the epileptogenic zone is reasonable in this population. Gross total resection should be the goal, with additional attention to resection of the epileptogenic zone when located in the noneloquent cortex.     

Discontinuation of medications after successful epilepsy surgery in children

To evaluate the need for antiepileptic drugs after successful epilepsy surgery in pediatric patients, we retrospectively reviewed patients who had epilepsy surgery and were seizure free or had rare nondisabling auras during the first 6 postoperative months. Association between drug discontinuation and seizure recurrence was evaluated using Cox proportional hazards multivariable survival analysis. Medications were withdrawn in 68 of 97 patients, seizure free (or with rare nondisabling auras) for >6 months after surgery; 57 of the 68 (84%) remained seizure free; the other 11 (16%) had seizure recurrence after 68 months (median). Seizure recurrence was controlled with medication in 7 of the 11 patients (3 have rare seizures, 1 frequent auras). Discontinuing medications at <6 mo, compared with later or no withdrawal, had significant risk for seizure recurrence (hazard ratio 5.8; 95% confidence interval 1.8, 17.5; P = 0.003). Of 29 patients who continued drugs, 28 (97%) remained seizure free after 37 months (median). Freedom from seizures 6 months after surgery predicted good outcome (95% seizure free, with or without medication). If discontinuation is offered after 6 months, the majority of patients (84%) can be expected to remain seizure free with no further need for medication. Although seizure breakthrough is possible in a smaller percentage, restarting drugs is likely to restore seizure control.     

Predicting seizure frequency after epilepsy surgery

OBJECTIVE: To identify clinical features related to seizure frequency after epilepsy surgery in patients with recurrent seizures. BACKGROUND: No studies have examined the differences between patients who have rare seizures and patients who experience frequent seizures after epilepsy surgery. Since seizure frequency correlates with morbidity and quality of life, it is desirable to know which preoperative clinical features predict postoperative seizure frequency. METHODS: Patients with recurrent seizures were placed in two categories: rare postoperative seizures (< or =2 per year) and frequent postoperative seizures (> or =12 per year) using seizure frequency in the second postoperative year. Variables included preoperative seizure frequency, age of first risk, age at first seizure, epilepsy duration, age at surgery, history of febrile convulsions, tonic-clonic seizures, status epilepticus, or family history, IQ, magnetic resonance imaging (MRI), and positron emission tomography (PET). Variables were analyzed using non-parametric tests to assess relationship to postoperative seizure frequency. RESULTS: Of 475 patients who had epilepsy surgery, 111 had rare or frequent seizures in the second postoperative year. After anterior temporal lobectomy (ATL), age of first risk< or =5 years and presence of mesial temporal sclerosis on MRI were associated with rare seizures (66% of patients), whereas lack of these risk factors was associated with frequent seizures (75% of patients) (p<0.03). For non-ATL operations, preoperative seizure frequency of > or =20 seizures per month was associated with frequent postoperative seizures (p=0.03). No other variables influenced outcome. CONCLUSIONS: Some preoperative clinical features correlate with postoperative seizure frequency in patients with recurrent seizures after epilepsy surgery. This has implications for the surgical decision making process and early postoperative management.     

Long-term seizure outcomes following resection of supratentorial cavernous malformations

Objective

Symptomatic supratentorial cavernous malformations may present with seizure, headache, neurological deficit, or a combination thereof. Factors that contribute to treatment algorithms commonly include patient age, lesion size and location, lesion multiplicity, hemorrhage history, and the ability to control seizure activity with medication. A better appreciation of the impact of patient and lesion characteristics on post-operative seizure control may provide insight into management strategies. To determine long-term seizure outcomes following surgical resection of supratentorial cavernous malformations, the predictive value of characteristics including seizure duration and number, presence of generalized seizures, and lesion multiplicity and size on seizure control rate was evaluated.

Methods

We performed a single institution retrospective review of consecutive patients with supratentorial cavernous malformations presenting with at least one seizure between 1995 and 2008. Univariate and multivariate analyses were used to determine the influence of patient and lesion characteristics on postoperative seizure control.

Results

Fifty-six patients met inclusion criteria. Mean follow-up duration was 87.9 months. At last follow-up there were 46 patients (82.1%) that were free from impairing seizures (Engel Class 1). Ten patients (17.9%) were classified as Engel Class 2–4. Univariate analysis demonstrated that only the presence of multiple cavernomas was associated with worse post-operative seizure outcome (p = 0.006). Multivariate analysis demonstrated that multiple cavernomas remained a significant predictor for development of worse seizure outcome controlling for number and duration of seizures prior to operation, presence of generalized tonic-clonic seizures, and size (odds ratio, 0.17; 95% confidence interval, 0.03, 0.99).

Conclusion

Resection of supratentorial cavernomas is associated with a high rate of postoperative seizure freedom. The presence of multiple cavernomas is predictive of seizure persistence following surgery.     

Long-Term Management of Seizures after Surgical Treatment of Supratentorial Cavernous Malformations : A Retrospective Single Centre Study

ObjectiveSeizure recurrence after the first-ever seizure in patients with a supratentorial cerebral cavernous malformation (CCM) is almost certain, so the diagnosis and treatment of epilepsy is justified. The optimal method of management of these patients is still a matter of debate. The aim of our study was to identify factors associated with postoperative seizure control and assess the surgical morbidity rate. MethodsWe retrospectively analysed 45 consecutive patients with a supratentorial CCM and symptomatic epilepsy in a single centre. Pre- and postoperative epidemiological data, seizure-related patient histories, neuroimaging results, surgery details and outcomes were obtained from hospital medical records. Seizure outcomes were assessed at least 12 months after surgery. ResultsThirty-five patients (77.8%) were seizure free at the long-term follow-up (Engel class I); six (13,3%) had rare, nocturnal seizures (Engel class II); and four (8.9%) showed meaningful improvement (Engel class III). In 15 patients (33%) in the Engel I group; it was possible to discontinue antiepileptic medication. Although there was not statistical significance, our results suggest that patients can benefit from early surgery. No deaths occurred in our study, and mild postoperative neurologic deficits were observed in two patients (4%) at the long-term follow-up. ConclusionSurgical resection of CCMs should be considered in all patients with a supratentorial malformation and epilepsy due to the favourable surgical results in terms of the epileptic seizure control rate and low postoperative morbidity risk, despite the use of different predictors for the seizure outcome.     

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.     

Long-term seizure outcome and risk factors for recurrence after extratemporal epilepsy surgery

Purpose: We aimed to assess long‐term seizure outcome and risk factors for seizure recurrence in a cohort of patients who have undergone extratemporal resection for management of refractory seizures. Methods: Eighty‐one patients underwent extratemporal resection at Austin Health, Melbourne, Australia (1991–2004). Seizure recurrence was any postoperative disabling seizure (complex partial seizure [CPS] ± secondary generalization). Multivariate Cox proportional hazards regression models examined potential preoperative and perioperative risk factors and the risk associated with early postoperative seizures (≤28 days postsurgery). The change between preoperative and postoperative seizure frequency was also measured. Key Findings: Median follow‐up was 10.3 years (range 1–17.7). The probabilities of freedom from disabling seizures (on or off antiepileptic medication) were 40.7% (95% confidence interval [CI] 30–51) at 1 month, 23.5% (95% CI 15–33) at 1 year, and 14.7% (95% CI 8–23) at 5 years postoperative. Reduction of disabling seizures to at least 20% of preoperative frequency was attained by 57% of patients at 5 postoperative years. Of the preoperative/perioperative factors, focal cortical dysplasia (FCD) type 1 (hazard ratio [HR] 1.90, 95% CI 1.08–3.34, p = 0.025) and incomplete resection (HR 1.71, 95% CI 1.06–2.76, p = 0.028) were independent recurrence risks. After surgery, an early postoperative seizure was the only factor associated with higher risk (HR 4.28 [2.42–7.57], p = 0.00). Significance: Distinction between subtypes of focal cortical dysplasia, which can be made using magnetic resonance imaging (MRI) criteria, may be useful for preoperative prognostication. Early seizures after surgery are not benign and may be markers of factors that contribute to seizure recurrence. Most patients achieve substantial reduction in seizure frequency. Further study of the significance of this reduction in terms of surgical “success” or otherwise is required.     

Short-term outcomes and predictors of post-surgical seizures in patients with supratentorial low-grade gliomas

To explore the predictive factors and short-term outcomes of post-surgical seizures in patients with supratentorial low-grade gliomas (LGGs). A consecutive series of 70 supratentorial LGG patients with seizures were reviewed to determine the predictors and short-term outcomes of seizures. Univariate analyses and multivariate logistic regression analyses were performed to determine the predictive factors associated with postoperative seizure outcomes. We identified the preoperative seizure frequency threshold by plotting a receiver operating characteristic curve. A Kaplan-Meier curve was constructed to illustrate the seizure-free survival rate of our cohort over time. 54 patients who remained seizure -free post-surgery were classified into the Engel class I, and the other 16 patients whose seizures relapsed were classified into Engel classes II–IV. Univariate and multivariate logistic regression analyses showed that the preoperative seizure frequency (X² = 16.069, P = 0.001), extent of resection (x² = 5.031, P = 0.025), IDH1 mutation (x² = 4.435, P = 0.035) and adjuvant chemotherapy of temozolomide (X² = 4.081, P = 0.043) were related to the postoperative short-term seizure outcome. The ROC curve indicated that the area under the curve for the preoperative seizure frequency test was 0.805 (95% confidence interval 0.690–0.920, p < 0.05), which corresponded to an optimal threshold of 2 preoperative seizures. The IDH1^WT status and adjuvant chemotherapy with temozolomide were related to a better post-operative seizure outcome. Within the first year after the surgical resection, seizures reoccurred among 16 patients (22.9%) with a mean time of 10.8 months. The preoperative seizure frequency, extent of resection, IDH1 status, and adjuvant chemotherapy with temozolomide were predictive factors of short-term postoperative seizure outcomes for supratentorial LGGs. To obtain a favorable seizure outcome, early intervention and removal are warranted. IDH1 mutation is the predictive biomarker of postoperative seizure outcomes. The adjuvant chemotherapy with temozolomide appears to be associated with better seizure outcomes, and it may be useful in helping to control the postoperative seizures.     

Does early postoperative drug regimen impact seizure control in patients undergoing temporal lobe resections?

Objective

To evaluate the impact of postoperative antiepileptic drug (AED) load on seizure control in patients who underwent surgical treatment for pharmacoresistant mesiotemporal lobe epilepsy during the first two postoperative years.

Patients and methods

532 consecutive patients (48.7% males and 51.7% females) who underwent surgical treatment for mesiotemporal lobe epilepsy were retrospectively evaluated regarding effects of AED load on seizures control during the first 2 years following epilepsy surgery. We analyzed whether postoperative increases in postoperative AED load are associated with better seizure control in patients initially not seizure free, and if postoperative decreases in postoperative AED load would increase the risk for seizure persistence or recurrence. For statistical analyses, Fisher’s exact and Wilcoxon test were applied.

Results

68.9, 64.0 and 59.1% of patients were completely seizure free (Engel Ia) at 3, 12 and 24 months after surgery, respectively. Patients in whom daily drug doses were increased did not have a higher rate of seizure freedom at any of the three follow-up periods. Of 16 patients achieving secondary seizure control at 12 months after surgery, only one did so with an increase in drug load in contrast to 15 patients who experienced a running down of seizures independent of drug load increases. Decreases in drug load did not significantly increase the risk for seizure recurrence. Of postoperatively seizure free patients at 3 months after surgery in whom AED were consequently reduced, 85% remained completely seizure free at 1 year and 76% at 1 year after surgery, respectively, as opposed to 86% each when AED was not reduced (differences n.s.). Mean daily drug load was significantly lower in seizure free patients at 12 and 24 months compared to patients with ongoing seizures.

Conclusion

In this large patient cohort stratified to the epilepsy syndrome neither did a postoperative reduction in drug load significantly increase the risk for seizure relapse nor did increases in drug dosages lead to improved seizure control. Mean drug load was on average lower in seizure free- than non-seizure free patients at 12 and 24 months of follow-up. Secondary seizure control after initial postoperative seizures in > 90% of cases occurred as a running down, independent of an AED increase. Thus, the effect of the surgical intervention rather than the postoperative drug regimen was the key determinant for seizure control. This finding supports a curative role of temporal lobe surgery rather than an effect rendering the majority of patients’ pharmacoresponsive with a critical role of the antiepileptic drug regime for seizure control.

     

Seizure outcome after resection of supratentorial cavernous malformations: a study of 168 patients

PURPOSE: The optimal management of cerebral cavernous malformations (CCMs) with epileptic seizures is still a matter of debate. The aim of our study was to examine seizure outcome in the largest published series of surgically treated patients with epilepsy due to a supratentorial CCM, and to define predictors for good surgical outcome. METHODS: We retrospectively studied 168 consecutive patients with a single supratentorial CCM and symptomatic epilepsy in a multicenter study. Pre- and postoperative clinical examinations, age at epilepsy onset, age at operation, type of symptoms due to the CCM (seizures, headache, hemorrhage, focal deficits), type and frequency of epileptic seizures, and the localization and size of the CCM were assessed. Seizure outcome was determined in the first, second, and third postoperative years. RESULTS: The CCM was completely resected in all patients. More than two thirds of the patients were classified as seizure free in the first 3 postoperative years. Predictors for good seizure outcome were age older than 30 years at the time of surgery, mesiotemporal CCM localization, CCM size <1.5 cm, and the absence of secondarily generalized seizures. No mortality occurred in our series, but only mild postoperative neurologic deficits in 12 (7%) patients. CONCLUSIONS: Considering the natural history of CCMs, the favorable neurologic and seizure outcome, surgical resection of CCMs should be considered in all patients with supratentorial CCMs and concomitant epilepsy, irrespective of the presence or absence of predictors for a favorable seizure outcome.     

合并癫痫的幕上低级别胶质瘤病人癫痫预后的影响因素分析

目的探讨合并癫痫的幕上低级别胶质瘤病人癫痫预后的影响因素。方法回顾性分析2015年6月至2019年1月手术治疗的80例合并癫痫的幕上低级别胶质瘤的临床资料。术后1年,采用Engel分级评估癫痫预后,Ⅰ级为预后良好,Ⅱ~Ⅳ级为预后不良。用多因素logistic回归分析检验影响癫痫预后的影响因素;受试者工作特征(ROC)曲线分析术前癫痫发作频率预测癫痫预后的价值。结果80例中,术后癫痫预后良好59例,预后不良21例。多因素logistic回归分析结果显示,异柠檬酸脱氢酶(IDH)1突变和术前癫痫发作频率高是胶质瘤病人术后癫痫的独立危险因素(P<0.05),全切肿瘤和术后化疗是保护性因素(P<0.05)。术前癫痫发作频率预测癫痫预后的ROC曲线下面积为0.805(95%置信区间0.685~0.914;P<0.05);当术前癫痫发作频率≥2次/月时,预测术后癫痫预后不良的灵敏度和特异度分别为92.86%和46.85%。结论IDH1突变和术前癫痫发作频率高是合并癫痫的幕上低级别胶质瘤病人癫痫预后不良的危险因素,而肿瘤全切除和术后化疗明显改善癫痫预后。     

When is a postoperative seizure equivalent to “epilepsy recurrence” after epilepsy surgery?

Purpose: Up to one‐half of epilepsy surgery patients will have at least one seizure after surgery. We aim to characterize the prognosis following a first postoperative seizure, and provide criteria allowing early identification of recurrent refractory epilepsy. Methods: Analyzing 915 epilepsy surgery patients operated on between 1990 and 2007, we studied 276 who had ≥1 seizure beyond the immediate postoperative period. The probability of subsequent seizures was calculated using survival analysis. Patients were divided into seizure‐free (no seizures for ≥1 year) and refractory (persistent seizures) and analyzed using multivariate regression analysis. Results: After a first seizure, 50% had a recurrence within 1 month and 77% within a year before the risk slowed down to additional 2–3% increments every two subsequent years. After a second seizure, 50% had a recurrence within 2 weeks, 78% within 2 months, and 83% within 6 months. Having both the first and second seizures within six postoperative months [odds ratio (OR) 4.04; 95% confidence interval (CI) 2.05–8.40; p = 0.0001], an unprovoked initial recurrence (OR 3.92; 95% CI 2.13–7.30; p < 0.0001), and ipsilateral spikes on a 6‐months postoperative electroencephalography (EEG) (OR 2.05; 95% CI 1.10–3.88; p = 0.025) predicted a poorer outcome, with 95% of patients who had all three risk factors becoming refractory. All patients with cryptogenic epilepsy and recurrent seizures developed refractoriness. Discussion: Seizures will recur in most patients who present with their first postoperative event, with one‐third eventually regaining seizure‐freedom. Etiology and early and unprovoked postoperative seizures with epileptiform activity on EEG at six postoperative months may predict recurrent medical refractoriness.     

Mental retardation in pediatric candidates for epilepsy surgery: the role of early seizure onset

PURPOSE: We sought to determine whether early age at seizure onset is a risk factor for mental retardation, independent of etiology. Assessment of risk for mental retardation with continued uncontrolled seizures plays a role in considerations of timing for epilepsy surgery. Previous studies have indicated that onset of seizures in the first years of life may be a risk factor for mental retardation, but the etiologies of the epilepsies were not included in the analyses. METHODS: Intellectual function was assessed at ages 2-20 years during presurgical evaluation in 100 patients with intractable epilepsy due to focal lesions limited to part of one lobe of the brain. Mental retardation (MR) was defined as Full-Scale Intelligence Quotient (FSIQ) < or =70. The age at seizure onset and the seizure frequency were obtained retrospectively. RESULTS: Younger ages at seizure onset were associated with lower FSIQ scores, and mean FSIQ was also significantly lower for patients with onset of epilepsy at < or =24 months of age (74.0 +/- 21.5) versus that in patients with onset of epilepsy later in life (87.8 +/- 18.8; p = 0.005). The frequency of patients with MR was significantly higher for patients with seizure onset at < or =24 months of age (15 of 33, 46%) than for patients with seizure onset later in life (eight of 67, 12%; p < 0.001). This difference persisted within etiologic subgroups. For patients with focal malformation of cortical development, MR was seen in eight (50%) of 16 patients with seizure onset at < or =24 months versus two (10%) of 20 patients with seizure onset at >24 months (p < 0.001); for patients with tumor, MR was seen in four (50%) of eight patients with seizure onset at < or =24 months versus four (13%) of 30 patients with seizure onset at >24 months (p = 0.003); and for patients with hippocampal sclerosis, MR was seen in two (28%) of seven patients with seizure onset at < or =24 months versus none of 30 patients with seizure onset at >24 months (NS). Within the subgroup with daily seizures, MR was present in 13 (65%) of 20 patients with seizure onset at < or =24 months versus five (17%) of 29 patients with seizure onset later in life (p = 0.001). CONCLUSIONS: These results indicate that onset of intractable epilepsy within the first 24 months of life is a significant risk factor for MR, especially if seizures occur daily. The risk based on early age at seizure onset appeared independent of etiology and persisted within subgroups of patients with focal malformation of cortical development, tumor, or hippocampal sclerosis. Prospective studies will be important to clarify whether early surgical intervention may reduce the risk for subsequent MR in carefully selected infants.     

Natural history of recurrent seizures after resective surgery for epilepsy.

Seizures persist or recur in 20-60% of patients after resective surgery for intractable partial epilepsy. Further information about the natural course of these seizures is lacking in the literature. During one decade of epilepsy surgery at a single institution, we identified 72 patients with recurrent postoperative seizures after resective procedures for epilepsy. Prospectively compiled seizure diaries, hospital records, and outpatient office records were reviewed and supplemented by telephone communications to assess subsequent seizure frequency. Follow-up data was available ranging from 6 months to 7 years 5 months (mean 3 years 5 months). The likelihood of persistent seizures and recurrent intractability was examined with life-tables. Seizures recurred within the first postoperative year in 86% of patients and were similar to preoperative events in 74% of patients. After the first seizure recurrence, there was 80% likelihood of persistent seizures in the next 6 years and 40% likelihood of intractability (more than one seizure a month despite optimal medical therapy). The interval until recurrence within the first postoperative year did not affect the likelihood of subsequent seizures or intractability. Late seizure recurrence (after the first year) was not associated with any instances of subsequent intractability. Recurrent seizures after extratemporal resections were more likely to become persistent and intractable than seizures recurring after temporal resections. This information provides rational prognostication and assists in counseling patients with recurrent seizures after resective surgery for intractable epilepsy.     

Is there an ideal way to discontinue the ketogenic diet?

It is unclear what the ideal weaning speed of the ketogenic diet should be and the resultant risk of seizure worsening. A retrospective chart review was performed of children who discontinued the ketogenic diet at Johns Hopkins Hospital from January 2000 to June 2010. Speed of discontinuation was categorized into immediate (<1 week), quick (1-6 weeks), or slow (>6 weeks) rates. One hundred and eighty-three children were identified. Children with both a longer diet duration (p=0.004) and lower seizure frequency (p<0.001) were weaned more slowly by our group. There was no significant difference in the incidence of seizures worsening between discontinuation rates. However, there was an increased risk of seizures worsening in those specifically with a 50-99% seizure reduction (30% vs. 8%, p<0.0001) and for that level of seizure improvement, in those who were receiving more anticonvulsants (1.4 vs. 0.8, p=0.01). In summary, there does not appear to be an increased risk of seizure exacerbation with rapid ketogenic diet discontinuations. Those who improved 50-99% and were receiving more anticonvulsants were at the highest risk overall. Discontinuing the ketogenic diet over weeks rather than months appears safe.     

Seizure outcomes following multilobar epilepsy surgery

Purpose: Outcomes following unilobar surgeries for refractory epilepsy have been well described. However, little is known about long‐term seizure outcomes following multilobar resections. The aim of the current study was to identify long‐term seizure control and predictors of seizure recurrence in this patient population. Methods: Records of patients who underwent multilobar epilepsy surgery at the Cleveland Clinic between 1994 and 2010 were retrospectively reviewed. A postoperative follow‐up of at least 6 months was required. Patients were classified as seizure free if they achieved an Engel class I at last follow‐up. Long‐term chances of seizure freedom were illustrated using a survival analysis, and predictors of recurrence were identified using Cox proportional hazard modeling. Key Findings: Sixty‐three patients with medically intractable epilepsy underwent multilobar surgical resections during the study period (mean follow‐up of 4.6 years). Predominant resection types included extended occipital (temporoparietooccipital, parietooccipital, temporooccipital: 57%), frontotemporal (21%), and temporoparietal (17%). Mean age at surgery was 21.4 years and mean age at seizure onset was 10.1 years. Fifty‐six percent of the patients underwent extraoperative invasive electroencephalography (EEG) evaluations. At 6 postoperative months, 71% (95% confidence interval (CI) 65–77) were seizure‐free (SF), 64% (CI 58–70) were SF at 1 year, 52% (CI 46–59) were SF at 5 years, and 41% (CI 32–50) remained SF at 10 years. Forty‐one patients had at least one breakthrough seizure after surgery (median timing of recurrence 6.1 months), with an Engel class 1 achieved again by last follow‐up in 12 of these 41 cases. Nine patients required a reoperation. Patients who underwent extended occipital/posterior quadrant resections had more favorable outcomes as compared to the other groups. With multivariate analysis, the type of resection (p = 0.03), preoperative auras (p = 0.03), an incomplete resection (0.03), and the presence of postoperative spikes (p = 0.0003) correlated with seizure recurrence. The risk of seizure recurrence for an incomplete resection was 2.3 (CI 1.53–3.36), preoperative aura 2.3 (CI 1.34–3.87), and postoperative spikes on surface EEG 2.5 (CI 1.29–4.71). Significance: A favorable outcome can be achieved in 41% of patients undergoing multilobar resections for epilepsy surgery at 10 years of follow‐up. Close to one‐third of patients who have breakthrough seizures after surgery are able to regain seizure freedom by last follow‐up. Predictors of recurrence include resection type (frontotemporal and parietotemporal resections did worse), presence of preoperative aura, an incomplete surgical resection, and the presence of postoperative interictal discharges on EEG.     

Epileptic seizures in supratentorial gliomas

Two hundred patients with supratentorial glioma; astrocytoma (pilocytic, fibrillary, gemistocytic) 82, mixed glioma (oligoastrocytoma) 46, oligodendroglioma 8, malignant (anaplastic) astrocytoma 33 and glioblastoma multiforme 31, surgically treated for the tumours and followed up for one to sixteen years, were retrospectively analysed for the incidence of pre and postoperative epileptic seizures. 122 patients (61%) had seizures preoperatively. 62 (50.8%) of them had at least one or more seizures during follow up. Seizures were persistent in 22 patients. Doubtful, or one or two minor seizures occurred in 19 cases. Six patients in this group had seizure only at the time of CT confirmed recurrence, after a seizure free interval of one to nine years. Amongst 78 patients who did not have seizures preoperatively, 24 (30.6%) developed seizures during the postoperative follow up period. Recurrent attacks were reported only by 5 patients while 15 patients had seizure(s) only at the time of recurrence of tumour. Two patients had a few seizures in the early postoperative period and none thereafter, while doubtful seizures were reported by two patients.     

Surgery for epilepsy due to cortical malformations: ten-year follow-up

Children with malformations of cortical development represent a significant proportion of pediatric epilepsy surgery candidates. From a cohort of 40 children operated on between 1980 and 1992 with malformation of cortical development, 38 were alive and had data 10 years after surgery. Age at surgery ranged from 6 months to 18 years (mean, 9.6 years). Thirty-six had partial seizures, and two had infantile spasms; 20 were nonlesional. Pathologic diagnoses were cortical dysplasia (n = 31) and developmental tumor (n = 7). At 10-year follow-up, 15 (40%) were seizure free, 10 (26%) had >90% seizure reduction, and 13 (34%) were improved or unchanged. Children seizure free at two-year follow-up were likely to remain seizure free. Ten-year seizure freedom was 72% in children with developmental tumors and 32% in the cortical dysplasia group. Complete resection was statistically significant for favorable outcome, and no patient with an incomplete resection was seizure free.     

Spikes on the postoperative EEG are related to preoperative spike frequency and postoperative seizures

PURPOSE: To investigate the factors which influence the persistence of interictal epileptiform discharges (IED) after epilepsy surgery. METHODS: In this retrospective study we included patients with intractable medial temporal lobe epilepsy (MTLE) who underwent presurgical evaluation including high-resolution MRI and video-EEG monitoring with seizure registration prior to an anterior temporal lobe resection. The postsurgical outcome was assessed by our team 6 months and 2 years after the surgery. RESULTS: One hundred and forty-seven patients fulfilled the inclusion criteria. The mean age of the patients was 31.8 (range 16-59 years). In 22 patients (15%) interictal epileptiform discharges were present on the postoperative routine EEG. We found that both the preoperative spike frequency ( P < 0.001 ) and postoperative seizures ( P = 0.04 ) were independently associated with the presence of IED on the postoperative routine EEG. The preoperative spike frequency was not associated with the postoperative outcome. The extent of resection showed no influence on the presence of postoperative IED. CONCLUSION: We hypothesize that two factors independently influence the presence of postoperative spikes: chronic interictal disturbance (represented as preoperative spike frequency) and the acute (postoperative) seizures. Our study confirmed that persistent postoperative IED had a prognostic value regarding the outcome of the epilepsy surgery.     

Risk factors for developing epilepsy after craniotomy in children

Introduction We performed a retrospective analysis of children undergoing supratentorial craniotomy, attempting to identify possible risk factors for postoperative epilepsy and the need for prophylactic anticonvulsant therapy.Materials and methods We analysed 107 consecutive patients (55% males) who had supratentorial craniotomy for a variety of diagnoses (tumours, trauma, infection, vascular malformations and others) during 1995–1999. Mean age at operation was 89 months (range: 1–180 months). Patients who presented with epilepsy were excluded. Postoperative epilepsy was considered present if patients required systematic pharmacological treatment, at a minimum follow-up of 6 months. Linear regression was used to analyse the effect of sex, anticonvulsant prophylaxis, duration of operation, closure of dura, postoperative infection, the diagnosis, anatomical region of brain affected, operation type (craniotomy/craniectomy) and the need for brain resection.Results Prophylactic anticonvulsants were given to 52% of the patients; 97% had craniotomy; in five patients, the dura was left open; in 33%, some kind of brain tissue resection had been performed; two patients (1.8%) developed postoperative infection; one patient died. Only 13 patients (12%) developed postoperative epilepsy. The only two factors with statistical significance were female sex (p=0.045) and the absence of dural closure (p=0.001). All other factors were not significant (p>0.258).Conclusions Postoperative epilepsy after supratentorial craniotomy is uncommon in children, incidence being 12%. The administration of prophylactic anticonvulsants does not appear to influence the risk of epilepsy. Surprisingly, females have statistically higher risk. Lack of dural closure has higher risk of epilepsy, but this may reflect the type of pathology.The material of this paper was presented at the 18th Biannual Congress of the European Society for Pediatric Neurosurgery, Kiruna, 15 June 2002.