Lesionectomy in the pediatric age

A systematic review and meta-analysis of surgeries performed for cerebral cavernous malformation-related epilepsy in pediatric patients

BACKGROUND

The clinical benefit of surgery for the treatment of cerebral cavernous malformation (CCM)-related epilepsy in pediatric patients is still controversial. Although surgical treatment of CCM-related epilepsy in children is widely recognized, the clinical benefits of controlling the seizure rate must be balanced against the risk of leading to perioperative morbidity.

METHODS

We conducted a comprehensive search to identify relevant studies via Ovid Medline, Web of Science and PubMed (January 1995-June 2020). The following search terms were used: "hemangioma, cavernous, central nervous system," "brain cavernous hemangioma," "cerebral cavernous hemangioma," "CCM," "epilepsy," and "seizures." The seizure control rate and the risk of postoperative adverse outcomes along with their 95% confidence intervals (CIs) were calculated.

RESULTS

A total of 216 patients across 10 studies were included in meta-analysis. The results showed that the control rate of epilepsy was 88% (95% CI: 76-95%). Four percent (95% CI: 2-10%) of the patients experienced temporary symptomatic adverse effects following surgical resection, and 3% (95% CI: 0-26%) of the patients developed permanent symptomatic adverse effects in the long-term follow-up after surgical excision of the CCMs. None of the patients died as a result of the CCMs or surgical treatment.

CONCLUSION

Surgery is an effective and safe treatment for CCM -related epilepsy in pediatric patients with a low risk of postoperative complications and death.

Are low-grade gliomas of mesial temporal area alone?

Background:

Temporal neocortex which appears normal on magnetic resonance imaging (MRI) may have pathological tissues in low-grade gliomas (LGG) of pure mesial temporal area. Resection of the cortex may be required together with mesial temporal glioma for satisfactory seizure and oncological outcome. The aim of this study was to explore the presence of any pathological tissue on the temporal cortex that appeared normal on preoperative MRI in patients with pure mesial temporal LGGs.

Methods:

This prospective study included 10 patients who underwent surgical resection of temporal lobe for LGG of mesial temporal area. The temporal neocortex with normal appearance on MRI and mesial temporal area were resected separately, and histopathological diagnosis was performed.

Results:

LGGs of the mesial temporal area were diagnosed with glioneuronal tumors in 7 (70%) and low-grade astrocytoma in 2 (20%) patients. Regarding the temporal cortex, gliosis and focal cortical dysplasia were found in 7 (70%) and 2 (20%) patients. In one patient temporal cortex did not contain any pathological tissue. All were seizure-free and no tumor recurrence was noted at the last follow-up.

Conclusion:

Mesial temporal LGGs are not alone and a high proportion of temporal neocortex appeared normal on preoperative MRI, may contain dual pathology. Thus, anterior temporal resection should be performed to have satisfactory seizure and oncological outcomes.

Surgical Management and Long-Term Seizure Outcome After Surgery for Temporal Lobe Epilepsy Associated with Cerebral Cavernous Malformations

OBJECTIVE

Operative strategies for cerebral cavernous malformation (CCM)-associated temporal lobe epilepsy and timing of surgical intervention continue to be debated. This study aimed to establish an algorithm to evaluate the efficacy of surgical intervention strategies, to maximize positive surgical outcomes and minimize postsurgical neurologic deficits.

METHODS

47 patients having undergone operation for CCM-associated temporal lobe epilepsy were retrospectively reviewed. They had received a diagnostic series for seizure localization, including long-term video electroencephalography (vEEG), high-resolution magnetic resonance imaging (MRI), and positron emission tomography-computed tomography (PET-CT). In patients with mesial temporal lobe CCMs, the involved structures (amygdala, hippocampus, or parahippocampal gyrus) were resected in addition to the lesions. Patients with neocortical epileptogenic CCM underwent extended lesionectomy guided by intraoperative electrocorticography; further performance of amygdalohippocampectomy depended on the extent of hippocampal epileptogenicity.

RESULTS

The study cohort contained 28 patients with drug-resistant epilepsy (DRE), 12 with chronic epilepsy (CE), and 7 with sporadic seizure (SS). Normal temporal lobe metabolism was seen in 7/7 patients of the SS group. Hypometabolism was found in all patients with chronic disease except for those with posterior inferior and middle temporal gyrus cavernous malformations (CMs). Of the 31 patients with superficial neocortical CCM, 7 had normal PET without hippocampal sclerosis, 14 had ipsilateral temporal lobe hypometabolism without hippocampal sclerosis, and 10 had obvious hippocampal sclerosis and hypometabolism. Seizure freedom in DRE, CE, and SS was 82.1%, 75%, and 100%, respectively. A significant difference was found between lesion laterality and postoperative seizure control; the rate was lower in left-sided cases because of less aggressive resection.

CONCLUSIONS

Our study demonstrates that the data from the presurgical evaluation, particularly regarding CM location, responsiveness to antiepileptic drugs, and temporal lobe metabolism, are crucial parameters for choosing surgical approaches to CCM-associated temporal lobe epilepsy. By this operative strategy, patients may receive maximized seizure control and minimized postsurgical neurologic sequelae.

Early and late epilepsy surgery in focal epilepsies associated with long-term epilepsy-associated tumors

OBJECTIVE

Epilepsy surgery is an effective means of treating focal epilepsy associated with long-term epilepsy-associated tumors. This study evaluated a large population of surgically treated patients with childhood onset of epilepsy and a histologically confirmed diagnosis of long-term epilepsy-associated tumors. The authors analyzed long-term seizure outcomes to establish whether the time of surgery and patients' ages were determinant factors.

METHODS

The authors separately investigated several presurgical, surgical, and postsurgical variables in patients operated on before (pediatric group) and at or after (adult group) the age of 18 years. Patients with < 24 months of postsurgical follow-up were excluded from the analysis.

RESULTS

The patients who underwent surgery before 18 years of age showed better seizure outcomes than those after 18 years of age (80% vs 53.3% Engel Class Ia outcome, respectively; p < 0.001). Multivariate analysis showed that the only variables significantly associated with seizure freedom were complete resection of the lesion, a shorter duration of epilepsy, and temporal lobe resection.

CONCLUSIONS

The findings of this study indicate that pediatric patients are more responsive to epilepsy surgery and that a shorter duration of epilepsy, complete resection, and a temporal lobe localization are determinant factors for a positive seizure outcome.

High-frequency oscillations detected in ECoG recordings correlate with cavernous malformation and seizure-free outcome in a child with focal epilepsy: A case report

Epilepsy associated with cavernous malformation (CM) often requires surgical resection of seizure focus to achieve seizure‐free outcome. High‐frequency oscillations (HFOs) in intracranial electroencephalogram (EEG) are reported as potential biomarkers of epileptogenic regions, but to our knowledge there are no data on the existence of HFOs in CM‐caused epilepsy. Here we report our experience of the identification of the seizure focus in a 3‐year‐old pediatric patient with intractable epilepsy associated with CM. The electrocorticographic recordings were obtained from a 64‐contact grid over 2 days in the epilepsy monitoring unit (EMU). The spatial distribution of HFOs and epileptic spikes were estimated from recording segments right after the electrode placement, during sleep and awake states separately. The HFO distribution showed consistency with the perilesional region; the location of spikes varied over days and did not correlate with the lesion. The HFO spatial distribution was more compact in sleep state and pinpointed the contacts sitting on the CM border. Following the resection of the CM and the hemosiderin ring, the patient became seizure‐free. This is the first report describing HFOs in a pediatric patient with intractable epilepsy associated with CM and shows their potential in identifying the seizure focus.

Occurrence predictors of the temporal interictal epileptic discharges in epilepsy patients with extratemporal lesions: A prospective cohort study

OBJECTIVE

Electrical kindling models of epilepsy suggest that medial temporal structures are more prone to be irritated. The aim of this study is to investigate the occurrence rate of temporal interictal epileptic discharges (TIEDs) in the epilepsy patients with extratemporal lesions (ETLs), and to determine the predictive factors for TIEDs in this cohort.

METHODS

Totally 221 patients were admitted for presurgical evaluation, and focal ETL were found in all of them by MRI examination. The occurrence rates of TIEDs in several groups with different brain lobe locations, durations; of epilepsy, seizure frequencies, and onset ages stages were assessed. We also evaluated the surgical outcome of; resection in this cohort.

RESULTS

The total occurrence rate of TIEDs in this cohort was 29.9%. The occurrence rate of TIEDs in the patients with longer durations (>5 or 10 years) was significantly higher than those with shorter duration (<1 year). These; patients with lower seizure frequency (<1 seizure/month) had a significantly decreased incidence of TIEDs; compared with those with higher frequency (>1 seizure/month or week). In the terms of the brain lobe locations; and age at onset, there were no differences between the groups. Furthermore, there were no differences in terms of the surgical outcomes between the patients with TIEDs and other patients in this series.

CONCLUSIONS

TIEDs were frequently recorded in these patients with ETLs, and the predictive factors for TIEDs included the epilepsy duration and seizure frequency.

SIGNIFICANCE

This study is instrumental for the presurgical EEG interpretationand the counseling of these ETLs patients considered for epilepsy surgery.

Microsurgical treatment of patients with refractory epilepsy and mesial temporal cavernous malformations: Clinical experience of a tertiary epilepsy center

BACKGROUND

Mesiotemporal cavernous malformation can occur in 10-20% of patients with cerebral cavernomas and are frequently associated with refractory.

METHODS

A retrospective investigation was performed in the epilepsy clinic of a Brazilian tertiary referral epilepsy center, from January 2000 to March 2012.

RESULTS

A total of 21 patients were included in the study. Thirteen patients (62%) evolved to Engel I; 5 (24%) to Engel II, 2 (10%) to Engel III, and 1 (5%) to Engel IV. We observed that 10 (48%) patients with 12 years or less of epilepsy duration evolved to Engel I and 1 (5%) to Engel II; whereas from a total of 10 patients with epilepsy duration of more than 12 years, 3 (30%) evolved to Engel I and 7 (70%) to Engel II, III, or IV (P < 0.001 [bilateral]; P1 ≠ P2).

CONCLUSION

Postsurgical seizure outcome for temporal lobe epilepsy associated with mesiotemporal cavernomas is very satisfactory.

Seizures in children with dysembryoplastic neuroepithelial tumors of the brain--A review of surgical outcomes across several studies

PURPOSE

In children and adolescents, dysembryoplastic neuroepithelial tumors (DNETs) of the brain present with seizures almost 100% of the time, potentially creating significant long-term morbidity and disability despite the generally indolent course of the lesion. These tumors also tend to be quite resistant to anti-epileptic drugs which, themselves, can be associated with long-term side effects and resultant disability. Many clinicians advocate early surgical resection of these lesions, but how effective this approach is, and how aggressive tumor removal should be, continues to be debated.

METHODS

We performed a systematic review of the relevant literature to identify all reports of DNET resections in pediatric patients published over the past 20 years. In all, over 3000 MEDLINE abstracts were reviewed, ultimately resulting in 13 studies with 185 pediatric DNET patients to review.

RESULTS

Surgical resection of the lesion was effective at improving seizures in over 98% of patients and at achieving long-term seizure freedom in 86%. Surgical resection of DNETs also appeared to be quite safe, with no reported perioperative deaths and an overall rate of postoperative complications of 12%; the vast majority of these complications were transient.

CONCLUSIONS

Total gross resection of the lesion was the only factor statistically correlated with long-term seizure freedom (r = 0.63, p = 0.03). However, data remain lacking regarding whether this translates into more extensive procedures-like brain mapping and partial lobectomies-being any more effective than simple lesionectomies alone. Further research is clearly needed to address this and other crucial questions.

Seizure outcomes of lesionectomy in pediatric lesional epilepsy with brain tumor -- single institute experience

PURPOSE

To determine the clinical characteristics, surgical strategy, and outcome in pediatric lesional epilepsy patients younger than 5years of age undergoing surgery in a single institute.

METHOD

Retrospective data were collected and analyzed on patients younger than 5years of age who underwent lesionectomy for lesional epilepsy at single institute from January 2001 to August 2010. Fourteen pediatric lesional epilepsy patients were enrolled in this study. Engel classification was used to classify seizure outcome.

RESULTS

Median preoperative seizure period was 1month (range, 1-21). Median post-operative follow up period was 35months (range 13-84). Ten patients who underwent gross total resection of tumor showed Engel class Ia seizure outcome without any antiepileptic drug (AED). Subtotal resection was performed in four patients to avoid eloquent area injury. Two of these four patients with subtotal removal became seizure-free (Engel class Ia) without AED, while two were in Engel class Ib with AED medication. There was no significant surgical morbidity or mortality.

CONCLUSION

Lesionectomy in children younger than 5years of age is relatively safe and effective in controlling seizures. Short preoperative seizure periods and total removal of tumor might be associated with good outcome. Therefore, early and complete lesionectomy alone may help allow for seizure freedom and optimal brain development in pediatric patients.

Seizure outcome of surgical treatment of focal epilepsy associated with low-grade tumors in children

OBJECT

Low-grade tumor (LGT) is an increasingly recognized cause of focal epilepsies, particularly in children and young adults, and is frequently associated with cortical dysplasia. The optimal surgical treatment of epileptogenic LGTs in pediatric patients has not been fully established.

METHODS

In the present study, the authors retrospectively reviewed 30 patients (age range 3-18 years) who underwent surgery for histopathologically confirmed LGTs, in which seizures were the only clinical manifestation. The patients were divided into 2 groups according to the type of surgical treatment: patients in Group A (20 cases) underwent only tumor removal (lesionectomy), whereas patients in Group B (11 cases) underwent removal of the tumor and the adjacent epileptogenic zone (tailored surgery). One of the patients, who underwent 2 operations, is included in both groups. Follow-up ranged from 1 to 17 years.

RESULTS

Sixteen (80%) of 20 patients in Group A had an Engel Class I outcome. In this group, 3 of 4 patients who were in Engel Classes II and III had temporomesial lesions. All patients in Group B had temporomesial tumors and were seizure free (Engel Class I). In this series, in temporolateral and extratemporal tumor locations, lesionectomy yielded a good seizure outcome. In addition, a young age at seizure onset (in particular < 4 years) was associated with a poor seizure outcome.

CONCLUSIONS

Tailored resection in temporomesial LGTs was associated with excellent seizure outcome, indicating that an adequate presurgical evaluation including extensive neurophysiological evaluation (long-term videoelectroencephalography monitoring) to plan appropriate surgical strategy is advised.

Adverse events occurring during invasive electroencephalogram recordings in children

BACKGROUND

In cryptogenic epilepsy or when multifocal seizure onset is suspected, intracranial monitoring of the EEG is required.

OBJECTIVE

To report on the adverse events related to electroencephalogram (EEG) intracranial recording in one of the largest pediatric series published and to discuss the avoidance of adverse events in our experience and with respect to a review of the literature.

METHODS

A retrospective analysis of our department database and hospital charts of 95 children operated on between 1994 and 2009 was performed.

RESULTS

Invasive recording was uneventful in 51.1% of cases. Observed frequency of infection was 14.9%, cerebrospinal fluid leak was 10.6%, brain swelling was 6.4%, and hemorrhage was 17%. Brain swelling was more frequent in older patients, whereas the length of recording, number of electrode contacts used, and presence of depth electrodes were not relevant. Cerebrospinal fluid leakage was completely prevented by the routine introduction of dural graft substitutes in 2003.

CONCLUSION

Invasive recordings carry a noticeable rate of adverse events but provide invaluable information in delineating the epileptogenic zone. The low incidence of such events among younger children suggests that invasive recordings can be successfully performed with low morbidity in this age group.

Diffusion tensor imaging assessment of the epileptogenic zone in children with localization-related epilepsy

BACKGROUND AND PURPOSE

Patients with MR imaging-negative epilepsy could have subtle FCD. Our aim was to determine if structural changes could be identified by using DTI in children with intractable epilepsy, from MR imaging-visible FCD and MR imaging-negative localization-related epilepsy, that were concordant with the epileptogenic zone as defined by using the MEG dipole cluster.

MATERIALS AND METHODS

Eight children with MR imaging-visible FCD and 16 with MR imaging-negative epilepsy underwent DTI and MEG. Twenty-six age-matched healthy children underwent DTI. Analysis was performed on controls across individual patients. Agreement between the location of DTI abnormalities and FCD and MEG dipole clusters was assessed.

RESULTS

In patients with MR imaging-visible FCD, abnormal FA, MD, λ(1), λ(2), and λ(3) were lobar concordant with the MEG dipole cluster in 4/8 (50.0%), 5/8 (62.5%), 3/8 (37.5%), 6/8 (75.0%), and 5/8 (62.5%), respectively. In patients with MR imaging-visible FCD, abnormal FA, MD, λ(1), λ(2), and λ(3) overlapped the x-, y-, and z-axes of the MEG dipole cluster in 1/8 (12.5%), 4/8 (50%), 4/8 (50%), 6/8 (75%), and 4/8 (50%), respectively, and with FCD in 1/8 (12.5%), 3/8 (37.5%), 0/8 (0%), 3/8 (37.5%), and 1/8 (12.5%), respectively. In patients with MR imaging-negative epilepsy, abnormal FA, MD, λ(1), λ(2), and λ(3) were lobar-concordant with the MEG dipole cluster in 11/16 (68.8%), 11/16 (68.8%), 8/16 (50.0%), 10/16 (62.5%), and 10/16 (62.5%), respectively, and overlapped the x-, y-, and z-axes of the MEG dipole cluster in 9/16 (56.3%), 10/16 (62.5%), 8/16 (50%), 8/16 (50%), and 8/16 (50%), respectively. There was no significant difference between abnormal DTI lobar concordance with the MEG dipole cluster in patients with MR imaging-visible FCD and MR imaging-negative epilepsy.

CONCLUSIONS

White matter changes can be detected with DTI in children with MR imaging-visible FCD and MR imaging-negative epilepsy, which were concordant with the epileptogenic zone in more than half of the patients.

Do we still need invasive recordings? If so for how much longer?

INTRODUCTION

This paper was presented at the International Society for Pediatric Neurosurgery Meeting in Cape Town in October 2008 during the post-meeting Focus Session on Intraoperative Neurophysiology.

DISCUSSION

It reflects the personal views of the author and is intended as a pragmatic approach to cases where a non-invasive pre-surgical evaluation has not been successful in localising the epileptogenic zone. It is based on the experience of the multi-disciplinary team at Great Ormond Street Hospital without whose support none of the surgical work would be possible.

Seizure outcome of epilepsy surgery in focal epilepsies associated with temporomesial glioneuronal tumors: lesionectomy compared with tailored resection

OBJECT

The authors retrospectively analyzed and compared seizure outcome in a series of 28 patients with temporomesial glioneuronal tumors associated with epilepsy who underwent 1 of 2 different epilepsy surgery procedures: lesionectomy or tailored resection.

METHODS

The 28 patients were divided into 2 groups, with 14 cases in each group. In Group A, surgery was limited to the tumor (lesionectomy), whereas Group B patients underwent tailored resection involving removal of the tumor and the epileptogenic zone as identified by a neurophysiological noninvasive presurgical study.

RESULTS

In Group A (10 male and 4 female patients) the interval between onset of seizures and surgery ranged from 1 to 33 years (mean 10.6 years). Patients' ages ranged from 3 to 61 years (mean 23.1 years). The epileptogenic lesion was on the left side in 6 patients and the right in 8 patients. Mean follow-up was 9.8 years (range 6.5-15 years). The Engel classification system, used to determine postoperative seizure outcome, showed 6 patients (42.8%) were Engel Class I and 8 (57.1%) were Engel Class II. In Group B (6 male and 8 female patients) the interval between onset of seizures and surgery ranged from 0.5 to 25 years (mean 8.6 years). Patients' ages ranged from 3 to 48 years (mean 22.3 years). The tumor and associated epileptogenic area was on the right side in 8 patients and the left in 6 patients. Mean follow-up duration was 3.5 years (range 1-6.5 years). Postoperative seizure outcome was Engel Class I in 13 patients (93%) and Engel Class II in 1 (7.1%).

CONCLUSIONS

The authors' results demonstrate a better seizure outcome for temporomesial glioneuronal tumors associated with epilepsy in patients who underwent tailored resection rather than simple lesionectomy (p = 0.005). For temporomesial glioneuronal tumors associated with epilepsy, performing a presurgical noninvasive neurophysiological study intended to identify the epileptogenic zone is necessary for planning a tailored surgery. Using this surgical strategy, the presence of temporomesial glioneuronal tumors constitutes a predictive factor of excellent seizure outcome, and therefore surgical treatment can be offered early to avoid both the consequences of uncontrolled seizures as well as the side effects of pharmacological therapy.

Benign lesions accompanied by intractable epilepsy in children

Epilepsy surgery has been proposed as a safe alternative treatment for intractable epilepsy in children, especially for patients with structural brain abnormalities. We studied 24 consecutive children who underwent surgery for intractable epilepsy. There were 12 males and 12 females. The mean age was 6.5 years. The seizures' duration ranged from 6 months to 2 years. The histopathological examination of the resected lesions revealed in 12 cases the presence of a ganglioglioma, in 7 cases dysembryoplastic neuroepithelial tumor, in 1 case a low grade glioma, in 2 cases cortical dysplasia, and in 2 cases cavernous malformations. In 18 cases, the lesions were located in the temporal lobe and in 6 cases the lesions were extratemporal. After a mean follow-up period of 4.4 years, 79% (19/24) of patients were seizure free. There were no permanent neurological deficits or deaths. Surgery for focal epilepsy in children is a safe procedure with favorable results.