Clinical and electroencephalographic features of infantile spasms associated with malformations of cortical development

Epilepsy surgery for children with epileptic spasms: A systematic review and meta-analysis with focus on predictors and outcomes

To conduct a systematic review of the literature regarding rates and predictors of favorable seizure outcome after resective surgery for epileptic spasms (ES) in pediatric patients. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses standards were followed. We searched PubMed, EMBASE, and Cochrane CENTRAL for articles published on the prevalence or incidence of epileptic spasm since 1985. Abstract, full-text review, and data extraction were conducted by two independent reviewers. Meta-analysis was performed to assess overall seizure freedom rate. Subject-level analysis was performed on a subset of studies to identify prognostic indicators. A total of 21 retrospective studies (n = 531) were included. Meta-analysis of all studies demonstrated a pooled seizure freedom rate of 68.8%. Subject-level analysis on 18 studies (n = 360) demonstrated a significant association between duration of spasms and recurrence of spasms after surgery, with an estimated increased risk of 7% per additional year of spasms prior to operation. Patients who underwent resective surgery that was not a hemispherectomy (i.e., lobectomy, lesionectomy, etc.) had an increased recurrence risk of 57% compared to patients who had undergone hemispherectomy. Resective surgery results in seizure freedom for the majority of pediatric patients with epileptic spasms. Patients who undergo hemispherectomy have lower risk of recurrence than patients who undergo other types of surgical resection. Increased duration of spasms prior to surgery is associated with increased recurrence risk after surgery. PLAIN LANGUAGE SUMMARY: Children with epileptic spasms (ES) that do not respond to medications may benefit from surgical treatment. Our study reviewed existing research to understand how effective surgery is in treating ES in children and what factors predict better outcomes. Researchers followed strict guidelines to search for and analyze studies published since 1985, finding 21 studies with a total of 531 patients. They found that, on average, nearly 70% of children became seizure-free after surgery. Further individual analysis of 360 patients showed that longer duration of spasms before surgery increased the risk of spasms returning by 7% per year. Additionally, children who had less extensive surgeries, such as removal of only a specific part of the brain, had a 57% higher risk of seizure recurrence compared to those who had a hemispherectomy, which removed or disconnected half of the brain. Overall, the study concludes that surgery can often stop seizures, especially when more extensive surgery is performed and when the surgery is done sooner rather than later.

Impact of Etiology on Seizure and Quantitative Functional Outcomes in Children with Cerebral Palsy and Medically Intractable Epilepsy Undergoing Hemispherotomy/Hemispherectomy

OBJECTIVE

To compare functional and seizure outcomes in children with vascular and dysplastic etiologies of cerebral palsy and medically intractable epilepsy following functional hemispherotomy or anatomic hemispherectomy.

METHODS

Consecutive patients satisfying inclusion criteria from 07/01/2015 to 12/01/2019 were reviewed for demographic data and seizure (Engel classification) and functional (Functional Independence Measure for Children) outcomes.

RESULTS

After a mean follow-up of 2 years 8 months (1 year 2 months), 11 of 18 patients achieved post-operative seizure freedom without significant difference between vascular (5/7) and dysplastic (6/11) etiologies (P = 0.64). Functional assessments were completed for 15 of 18 of subjects, split comparably between groups. Mean change in the Functional Independence Measure for Children from pre-operative baseline to inpatient rehabilitation admission (vascular, -35.3 [13.2]; malformation of cortical development{MCD}, -34.5 [25.0]; P = 0.69), inpatient rehabilitation admission to discharge (vascular, 18.7 [9.0]; MCD, 20.8 [11.4]; P = 0.60), and pre-operative evaluation to clinic follow-up (vascular, -7.6 [9.7]; MCD, -3.6 [19.3]; P = 0.61) did not differ between groups.

CONCLUSION

Quantitative functional and seizure outcomes following functional hemispherotomy or anatomic hemispherectomy did not differ significantly between vascular and dysplastic etiologies of cerebral palsy and medically intractable epilepsy in this study. Hemispheric surgery resulted in minor functional declines from baseline following comprehensive multidisciplinary therapy.

Seizure Semiology in Focal and Generalized Epilepsies: Distinctive and Overlapping Features

Studying seizure semiology is the first step in evaluating any patient with epilepsy which leads the way to further investigations and management, particularly in differentiating focal and generalized epilepsies. While the usefulness of semiological analysis has been confirmed through decades' worth of research and clinical practice, there remains some instances when the line between focal and generalized semiological features is blurred leading to difficulties identifying the type of epilepsy at hand. This in turn can lead to delayed or wrong diagnoses with significant implications.In this review article, we explain the role of semiology in epilepsy, specifically in differentiating focal versus generalized epilepsies and cover the semiological features for both groups. We also discuss the occasional overlapping semiology between the two groups and provide case examples.

Preoperative evaluation and surgical management of infants and toddlers with drug-resistant epilepsy

OBJECTIVE Despite perioperative risks, epilepsy surgery represents a legitimate curative or palliative treatment approach for children with drug-resistant epilepsy (DRE). Several factors characterizing infants and toddlers with DRE create unique challenges regarding optimal evaluation and management. Epilepsy surgery within children < 3 years of age has received moderate attention in the literature, including mainly case series and retrospective studies. This article presents a systematic literature review and explores multidisciplinary considerations for the preoperative evaluation and surgical management of infants and toddlers with DRE. METHODS The study team conducted a systematic literature review based on Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, targeting studies that investigated children < 3 years of age undergoing surgical treatment of DRE. Using the PubMed database, investigators selected peer-reviewed articles that reported seizure outcomes with or without developmental outcomes and/or perioperative complications. Studies were eliminated based on the following exclusion criteria: sample size < 5 patients; and inclusion of patients > 3 years of age, when demographic and outcomes data could not be separated from the cohort of patients < 3 years of age. RESULTS The study team identified 20 studies published between January 1990 and May 2017 that satisfied eligibility criteria. All selected studies represented retrospective reviews, observational studies, and uncontrolled case series. The compiled group of studies incorporated 465 patients who underwent resective or disconnective surgery (18 studies, 444 patients) or vagus nerve stimulator insertion (2 studies, 21 patients). Patient age at surgery ranged between 28 days and 36 months, with a mean of 16.8 months (1.4 years). DISCUSSION The study team provided a detailed summary of the literature review, focusing on the etiologies, preoperative evaluation, surgical treatments, seizure and developmental outcomes, and potential for functional recovery of infants and toddlers with DRE. Additionally, the authors discussed special considerations in this vulnerable age group from the perspective of multiple disciplines. CONCLUSIONS While presenting notable challenges, pediatric epilepsy surgery within infants and toddlers (children < 3 years of age) offers significant opportunities for improved seizure frequency, neuro-cognitive development, and quality of life. Successful evaluation and treatment of young children with DRE requires special consideration of multiple aspects related to neurological and physiological immaturity and surgical morbidity.

A long-term, clinical study on symptomatic infantile spasms with focal features

BACKGROUND

We studied the clinical, neuroradiological and EEG characteristics of patients with infantile spasms (IS) who showed focal features to reveal their long-term prognoses and treatment responses.

SUBJECTS AND METHODS

Subjects included 69 patients with IS who consecutively visited our hospital. We tentatively classified the subjects into focal IS (fIS) and diffuse WS (dIS) groups based on the presence and absence of more than two of the following findings, respectively: (1) epileptic spasms (ES) that were asymmetric, (2) a focal epileptic EEG abnormality, (3) a lateralized neurological abnormality, (4) a focal brain MRI and (5) a focal SPECT abnormality.

RESULTS

We found 23 cases with fIS and 46 cases with dIS. ES responded more frequently in fIS than dIS group (100% vs. 80%; P=0.02) to the initial ACTH trial although the subsequent seizure relapse occurred more frequently in fIS than dIS group (74% vs. 38%; P=0.0006). The second course of ACTH trial brought a short as well as long-term remission in both groups (6/8 cases vs. 5/6 cases). Later in the clinical course, the fIS patients tended to display a focal epileptic EEG abnormality and to develop focal seizures. In our series, approximately one-third of patients with fIS later showed either only a focal epileptic EEG abnormality, a focal epileptic EEG abnormality with focal seizures, or bilateral asymmetric EEG foci with disabling seizures, respectively.

CONCLUSION

It is useful to classify patients with IS into fIS and dIS groups based on various lateralizing signs because the classification provides practical information regarding the long-term outcome and treatment strategy.

Stereoelectroencephalography in the presurgical evaluation of focal epilepsy in infancy and early childhood

OBJECT

The authors report on the use of stereoelectroencephalography (stereo-EEG) in the presurgical electroclinical evaluation of infants and very young children with focal drug-resistant epilepsy.

METHODS

Fifteen patients (9 girls and 6 boys, mean age 34.1 ± 7.3 months, range 21-45 months), potentially candidates to receive surgical treatment for their focal drug-resistant epilepsy, were evaluated using stereo-EEG recording for a detailed definition of the epileptogenic zone. Stereoelectroencephalography was indicated because neuroradiological (brain MRI) and video-EEG data failed to adequately localize the epileptogenic zone. Stereotactic placement of multicontact intracerebral electrodes was preceded by the acquisition of all pertinent anatomical information from structural and functional MRI and from brain angiography, enabling the accurate targeting of desired structures through avascular trajectories. Stereoelectroencephalography monitoring attempted to record habitual seizures; electrical stimulations were performed to induce seizures and for the functional mapping of eloquent areas. Stereoelectroencephalography-guided microsurgery, when indicated, pointed to removal of the epileptogenic zone and seizure control.

RESULTS

Brain MRI revealed an anatomical lesion in 13 patients (lobar in 2 cases, multilobar or hemispheric in 11 cases) and was unremarkable in 2 patients. One patient underwent 2 stereo-EEG studies. The arrangement of the intracerebral electrodes was unilateral in all but 1 case. One patient died the day following electrode placement due to massive brain edema and profound hyponatremia of undetermined cause. In 8 cases intracerebral electrical stimulations allowed mapping of functionally critical areas; in 3 other cases that received purposeful placement of electrodes in presumably eloquent areas, no functional response was obtained. Of the 14 patients who completed stereo-EEG monitoring, 1 was excluded from surgery for multifocality of seizures and 13 underwent operations. Postoperatively, 2 patients exhibited an anticipated, permanent motor deficit, 3 experienced a transient motor deficit, and 2 experienced transient worsening of a preexisting motor deficit. Three patients developed a permanent homonymous hemianopia after posterior resections. Histological analysis revealed cortical malformations in 10 cases. Of the 10 patients with a postoperative follow-up of at least 12 months, 6 (60%) were seizure-free (Engel Class Ia), 2 (20%) experienced a significant reduction of seizures (Engel Class II), and 2 (20%) were unchanged (Engel Class IV).

CONCLUSIONS

The present study indicates that stereo-EEG plays a prominent role in the presurgical evaluation of focal epilepsies also in the first years of life and that it may offer a surgical option in particularly complex cases that would have scarcely benefitted from further medical treatment. Results of stereo-EEG-guided resective surgery were excellent, with 80% of patients exhibiting a substantial improvement in seizures. In consideration of the potentially life-threatening risks of major intracranial surgery in this specific age group, the authors recommend reserving stereo-EEG evaluations for infants with realistic chances of benefiting from surgery.

Infantile spasms: review of the literature and personal experience

This epileptic disorder has become a classic topic for neuropediatricians and the interest is documented by the large number of publications on this subject.The relative frequency among the epileptic syndromes is an another reason why not only neuropediatricians but also general pediatricians must be fully informed about diagnostic, clinical, imaging and genetic aspects.Early diagnosis is of paramount importance in order to obtain even complete results in patients with so called idiopathic situations. A number of problems are still to be solved. There is no agreement on the type and the schedule of treatment. A common denominator about this problem is not jet available even if some advances in this regard have been accomplished. Of paramount importance is an accurate clinical and laboratory examination as a prerequisite regarding prognosis and results of therapy in every single case.However, even if more than 170 years have elapsed since the first communication of dr. West on the peculiar syndrome that his child was suffering of, the interest of scientists on this subject has now been enriched and rewarded.

Resective pediatric epilepsy surgery in Lennox-Gastaut syndrome

OBJECTIVE

The objective of this study was to evaluate the role of resective pediatric epilepsy surgery for Lennox-Gastaut syndrome (LGS).

METHODS

We analyzed clinical data of 27 children and adolescents who had LGS and underwent resective epilepsy surgery despite abundant (>30% of preoperative interictal and/or ictal epileptiform discharges) generalized or generalized contralateral maximal and multiregional electroencephalogram abnormalities.

RESULTS

On high-resolution MRI, cerebral lesions were noted in 23 (85.2%) patients but not in 4 (14.8%) patients. The age of patients at the time of surgery was between 1.7 and 17.3 years (mean: 7.8 years). Surgeries were lobar or multilobar resection in 21 (77.8%) patients and hemispherotomy in 6 (22.2%). At a mean of 33.1 months' postoperative follow-up, 16 (59.3%) patients had no seizures and 4 (14.8%) had infrequent seizures. Of 4 patients without brain abnormalities found on MRI, 2 patients became seizure-free after resective surgery was performed on the basis of electrophysiologic studies and concordant results in other multimodal neuroimages. Malformation of cortical development was the most common pathology and was seen in 20 (74.1%) patients, but 2 (7.4% patients) did not show any abnormal pathology. Sixteen (72.7%) patients, including 14 who had no seizures and 2 who had infrequent seizures after surgery, showed an increase in developmental quotient. No clinical profile was significantly associated with postoperative seizure-free rate.

CONCLUSIONS

Resective epilepsy surgery should be considered for children with LGS, despite abundant generalized and multiregional electroencephalogram abnormalities.

Approach to pediatric epilepsy surgery: State of the art, Part II: Approach to specific epilepsy syndromes and etiologies

The second of this 2-part review depicts the specific approach to the common causes of pediatric refractory epilepsy amenable to surgery. These include tumors, malformations due to abnormal cortical development, vascular abnormalities and certain epileptic syndromes. Seizure freedom rates are high (usually 60-80%) following tailored focal resection, lesionectomy, and hemispherectomy. However, in patients in whom the epileptogenic zone overlaps with unresectable eloquent cortex, and in certain epileptic syndromes, seizure freedom may not be achievable. In such cases, palliative procedures such as callosotomy, multiple subpial transections and vagus nerve stimulation can achieve reduction in seizure severity but rarely seizure freedom. Integration of the new imaging techniques and the concepts of neuronal plasticity, the epileptogenic lesion, the ictal onset, symptomatogenic, irritative, and epileptogenic zones is an expanding and dynamic process that will allow us, in the future, to better decide on the surgical approach of choice and its timing.

ICTAL EEG Fast Activity in West Syndrome: From Onset to Outcome

PURPOSE

To characterize the fast EEG activities associated with infantile spasms in West syndrome, and their value in predicting the recurrence and localization of late seizures.

METHODS

We selected 23 infants who were followed for at least 2 years. Selected EEG recordings underwent autospectra, coherence, and phase analyses in order to assess the changes during follow-up.

RESULTS

Short discharges of fast-rhythms (331 +/- 190 ms) with a lateralized onset were detected in 18 of the 23 infants (78.3%). There were no significant differences in the parameters characterizing ICTAL beta-activity (frequency, duration, inter-hemispheric coherence, or transfer time) between the infants with or without seizure recurrence. However, beta-discharges with a consistent location formed part of the ICTAL EEG in all 10 infants with seizure recurrence, but only in eight (61.5%) of those who remained seizure-free (SF) (p < 0.05). In all but one of the infants experiencing seizure recurrence, the ICTAL discharges associated with the late seizures apparently originated from the same hemisphere as that involved at the beginning of the spasm-associated beta-activity, although the precise location varied.

CONCLUSIONS

Spectral, coherence and phase analyses detected spasm-associated runs of lateralized beta-rhythms in many of our infants with West syndrome. This ICTAL pattern significantly correlated with seizure recurrence. The consistent lateralization of the ICTAL EEG events associated with both the early spasms and late seizures suggests that EEG beta-activities should be considered as indicating local cortical dysfunction in infants who fail to respond to early treatment and often progress toward severe epilepsy.