Epilepsy surgery in infancy

Long-term outcomes after surgery for catastrophic epilepsy in infants: institutional experience and review of the literature

OBJECTIVE

Uncontrolled epilepsy is associated with serious deleterious effects on the neurological development of infants and has been described as "catastrophic epilepsy." Recently, there has been increased emphasis on early surgical interventions to preserve or rescue neurodevelopmental outcomes in infants with early intractable epilepsy. The enthusiasm for early treatments is often tempered by concerns regarding the morbidity of neurosurgical procedures in very young patients. Here, the authors report outcomes following the surgical management of infants (younger than 1 year).

METHODS

The authors performed a retrospective review of patients younger than 1 year of age who underwent surgery for epilepsy at Miami (Nicklaus) Children's Hospital and Jackson Memorial Hospital between 1994 and 2018. Patient demographics, including the type of interventions, were recorded. Seizure outcomes (at last follow-up and at 1 year postoperatively) as well as complications are reported.

RESULTS

Thirty-eight infants (median age 5.9 months) underwent a spectrum of surgical interventions, including hemispherectomy (n = 17), focal resection (n = 13), and multilobe resections (n = 8), with a mean follow-up duration of 9.1 years. Hemimegalencephaly and cortical dysplasia were the most commonly encountered pathologies. Surgery for catastrophic epilepsy resulted in complete resolution of seizures in 68% (n = 26) of patients, and 76% (n = 29) had a greater than 90% reduction in seizure frequency. Overall mortality and morbidity were 0% and 10%, respectively. The latter included infections (n = 2), infarct (n = 1), and immediate reoperation for seizures (n = 1).

CONCLUSIONS

Surgical intervention for catastrophic epilepsy in infants remains safe, efficacious, and durable. The authors' work provides the longest follow-up of such a series on infants to date and compares favorably with previously published series.

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.

Ketogenic Diet Therapy in Infants: Efficacy and Tolerability

PURPOSE

This study evaluated tolerability and efficacy of the ketogenic diet in infants less than 12 months of age.

METHODS

Infants less than 12 months of age, commencing the ketogenic diet between September 2007 and July 2016 were identified. Records were reviewed for epilepsy details, diet initiation details, efficacy and tolerability.

RESULTS

Twenty-seven infants commenced the ketogenic diet (56% male, median age seven months). Median age at seizure onset was 1.9 months and 92% had daily seizures. An epilepsy syndrome was noted in 19 (West-11, epilepsy in infancy with migrating focal seizures-5, early myoclonic encephalopathy-1, Ohtahara-1, Dravet-1). Infants were on a median of two and had failed a median of one medications for lack of efficacy. All initiated a traditional ketogenic diet at full calories without fasting, and all but one started the diet in hospital. Significant hypoglycemia during initiation was seen in two - both had emesis +/- decreased oral intake. Eighty-eight percent developed urinary ketosis by 48 hours and all were successfully discharged on the diet (median ratio 3:1). Of those continuing dietary therapy, responder rates at one, six and 12 months were 68%, 82% and 91%, with 20%, 29% and 27% achieving seizure freedom. By 12 months, two stopped the diet for serious adverse effects, five discontinued for lack of efficacy, six were lost to follow-up and two died of unrelated causes.

CONCLUSIONS

The ketogenic diet is an effective and well-tolerated treatment for infants with intractable epilepsy. In-hospital initiation is strongly recommended due to risk of hypoglycemia with emesis or reduced intake.

State of the Art Approach to the Classification of Epileptic Seizures and Epilepsies

In the light of the latest knowledge acquired from clinical and laboratory research dealing with genetic, molecular biology and neuroimaging, existing classifications were successively revised by the International League Against Epilepsy (ILAE) in 2001, 2006, and 2010. In the latest classification established in 2010, proposals articulated radical changes in terms of concepts and definitions of the previously published classifications and put forward new classifications for epileptic seizures, epilepsies and electroclinical syndromes. This review refers to the changes of the new classification with their reasons and criticisms.

[Sturge-Weber syndrome]

Sturge-Weber syndrome (SWS) is a rare congenital disease which affects the brain, the skin and the eyes. It is a sporadically occurring neurocutaneous syndrome affecting the intracerebral veins (venous angiomatosis). The frequency is estimated to be 1 in 50,000 births [1]. The main symptom is intracranial leptomeningeal angiomatosis which mostly affects the occipital and posterior parietal lobes and can occur unilaterally and also bilaterally. Facial cutaneous vascular alterations occur ipsilaterally in the form of port wine stains (nevus flammeus) which are normally found in the catchment area of the trigeminal branch VI. Other clinical symptoms associated with SWS are seizures, glaucoma, headaches, transient neurological stroke-like episodes and cognitive impairment. Neurological cortical symptoms often include hemiparesis, hemiatrophy and hemianopsia.

Predictors of seizure-free outcome after epilepsy surgery for pediatric tuberous sclerosis complex

PURPOSE

Variable predictors of postsurgical seizure outcome have been reported in children with tuberous sclerosis complex (TSC). We analyzed a large surgical series of pediatric TSC patients in order to identify prognostic factors crucial for selection of subjects for epilepsy surgery.

METHODS

Thirty-three children with TSC who underwent excisional epilepsy surgery at Miami Children's Hospital were retrospectively reviewed. A total of 29 clinical, neuropsychological, electroencephalography (EEG), magnetic resonance imaging (MRI), and surgical variables were analyzed and related to seizure outcomes. Univariate Barnard's exact test, Wilcoxon's rank-sum test, and multivariate statistical Cox's model were used to examine the significance of associations between the variables and seizure outcome.

KEY FINDINGS

Eighteen patients (55%) have been seizure-free 2 years after (final) surgery; postoperative complications occurred in five subjects (15%). Complete removal of epileptogenic tissue detected by both MRI and intracranial EEG, regional scalp interictal EEG patterns, and agreement of interictal and ictal EEG localization were the most powerful predictors of seizure-free outcome. Other significant predictors included occurrence of regional scalp ictal EEG patterns, fewer brain regions affected by tubers, presence of preoperative hemiparesis, and one-stage surgery. Remaining factors such as age at seizure onset, incidence of infantile spasms or other seizure types, duration of epilepsy, seizure frequency, mental retardation, as well as types and extent of resections did not influence outcome.

SIGNIFICANCE

Perioperative features rather than preoperative variables are the most important determinants of postsurgical seizure outcome in patients with TSC. Our findings may assist in the surgical management of these patients.

Pediatric epilepsy surgery

Whereas there is no specific neurosurgical technique in pediatric epilepsy, the frequency of each type of surgery is very different from epilepsy surgery applied in adults, and reflects the underlying etiologies, which are much more diverse in children, with malformations of cortical development and tumors as the prevailing etiologies. Extensive resective or disconnective procedures for extratemporal epilepsy are more frequently performed in infants and younger children, whereas temporo-mesial resection is by far the most common surgical treatment for adults with epilepsy. More recently, less invasive techniques in children with an extensive epileptogenic zone, such as multilobar disconnection, hemispherotomy and other functional hemispherectomy variants, have been introduced in order to reduce duration of surgery, perioperative morbidity and length of hospital stay. Likewise, minimally invasive techniques are utilized, such as the endoscopic disconnection of hypothalamic hamartomas for gelastic epilepsy. This development has been encouraged with the introduction of image-guided navigation systems for the preoperative planning and during surgery. Historically, epilepsy surgery for children has been established much later than for adults. Apart from the particular aspects in perioperative management of younger infants, surgery-related morbidity as well as seizure outcome is in general similar to those in adults, depending rather on each type of surgery.

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.

Craniosynostosis following hemispherectomy in a 2.5-month-old boy with intractable epilepsy

The authors report on the case of a 6-week-old boy who presented with infantile spasms. At 2.5 months of age, the patient underwent a right hemispherectomy. Approximately 3 months postoperatively, the patient presented with left coronal craniosynostosis. Subsequent cranial vault remodeling resulted in satisfactory cosmesis. Four years after surgery, the patient remains seizure free without the need for anticonvulsant medications. The authors believe this to be the first reported case of iatrogenic craniosynostosis due to hemispherectomy, and they describe 2 potential mechanisms for its development. This case suggests that, in the surgical treatment of infants with intractable epilepsy, minimization of brain volume loss through disconnection techniques should be considered, among other factors, when determining the best course of action.

Surgical treatment for localization-related infantile spasms: excellent long-term outcomes

OBJECTIVE

Focal epileptogenic lesions can manifest as infantile spasms, a catastrophic type of epilepsy. Although early surgery for catastrophic epilepsies has shown positive effects, little is known regarding long-term outcomes. The present study examined long-term outcomes in patients with localization-related infantile spasms treated surgically.

METHODS

Data from localization-related infantile spasm cases treated surgically between 1998 and 2002 at the Asan Medical Center were retrospectively reviewed. Presurgical evaluation, surgery, postoperative seizure frequency and developmental outcome data were analyzed.

RESULTS

Five patients met the inclusion criteria, and had etiologies of tuberous sclerosis, fetal infection, encephalomalacia, malformation of cortical development and low-grade astrocytoma, respectively. The mean seizure onset age was 5.4 months (range, 3 days to 11 months), and the mean age at surgery was 19 months (range, 9-29 months). Two patients underwent a functional hemispherectomy, and the remaining three underwent lesionectomy or temporal lobectomy. The follow-up duration was 6-9 years. We found that following surgery, 4 of the 5 patients were seizure-free at the final follow-up. The 2 patients with low grade astrocytoma and cortical dysplasia, respectively showed relatively good developmental outcomes.

CONCLUSION

Surgery may be an excellent option for treating selected patients with infantile spasms due to unilateral or focal congenital or early-acquired cortical lesions. However, developmental outcomes appear to be strongly linked to etiology and the pre-operative developmental level.

Epilepsy surgery for the neurocutaneous disorders

Patients with neurophakomatoses were not always considered to be candidates for surgical resection of epileptogenic foci, given the multifocal nature of their disease. Advances in imaging, monitoring, and surgical technique have allowed the identification of particularly active areas of cortex that may provide these patients with better seizure control than medications alone. Options for surgical resection range from focal resections (in those with localized disease) to hemispherectomies (in those with hemispheric involvement).

Early epilepsy surgery

Uncontrolled epilepsy is associated with progressive cortical and hippocampal atrophy, substantial cognitive and psychosocial morbidity, and increased mortality. Seizure freedom is required to reverse such morbidity and mortality. Surgery is vastly superior to medical therapy for patients with chronic, refractory temporal lobe seizures, and is now the standard of care for these patients. On the other hand, the concept of early surgery requires further exploration and definition. Although there is no robust, direct evidence to support early epilepsy surgery, case series and cohort studies report an association between earlier surgery and better outcomes. The evidence for earlier epilepsy surgery is reviewed.

Sturge-Weber syndrome: a review

Sturge-Weber syndrome is a rare disorder that occurs with a frequency of approximately 1 per 50,000. The disease is characterized by an intracranial vascular anomaly, leptomeningeal angiomatosis, most often involving the occipital and posterior parietal lobes. Facial cutaneous vascular malformations, seizures, and glaucoma are among the most common symptoms and signs. Stasis results in ischemia underlying the leptomeningeal angiomatosis, leading to calcification and laminar cortical necrosis. The clinical course is highly variable and some children experience intractable seizures, mental retardation, and recurrent strokelike episodes. In this review, we describe the syndrome's characteristic features, clinical course, and optimal management.

Therapeutics in pediatric epilepsy, Part 2: Epilepsy surgery and vagus nerve stimulation

When antiepileptic drugs fail to relieve seizures adequately in children and adolescents, more invasive therapies such as epilepsy surgery and an implanted device to stimulate the vagus nerve should be considered. Temporal lobectomy is an effective treatment of complex partial and secondarily generalized tonic-clonic seizures arising in the mesial structures or lateral temporal neocortex. Excellent outcomes (seizure free or rare, nondisabling seizures) are achieved in at least 70% of children. The most common adverse effect is a superior quadrant field cut that is usually asymptomatic. Transient and more long-lasting language difficulties have been reported when the surgery involves the dominant temporal lobe. The excellent outcome rate for extratemporal surgery ranges from approximately 20% to 80%, with better results seen in patients with an identifiable lesion. Potential morbidity is related to the region of resected neocortex. Corpus callosotomy is an excellent procedure for palliation but is not a cure for seizures that cause falls, with substantial improvement seen in more than 80% of patients. Potential adverse effects include more intense focal seizures and dysphasia, depending on the developmental level of the individual. Hemispherectomy provides seizure relief in 60% to 80% of patients with hemispherical pathologies such as Sturge-Weber or Rasmussen syndromes. Operative mortality has been reported in the range of 0% to 6%; other morbidities include infection and hydrocephalus. Stimulation of the vagus nerve has reduced partial seizures by 50% or more in approximately one third of patients. No adverse cognitive or systemic effects are associated with use of the implanted vagus nerve stimulator.