Summary Purpose Implantation of subdural grids and invasive electroencephalography (EEG) monitoring is important to define the ictal‐onset zone and eloquent cortex in selected patients with medically refractory epilepsy. The objective of this systematic review is to summarize data about adverse events related to this procedure. Methods English‐language studies published up to July 2012, reporting such adverse events were reviewed. Outcome measures included demographic variables; surgical protocol including number of subdural electrodes implanted per patient, duration of monitoring, antibiotic, and steroid prophylaxis; and adverse events. Key Findings Twenty‐one studies were identified including a total of 2,542 patients. The reported mean number of electrodes per patient and duration of monitoring varied from 52 to 95 and 5 to 17 days, respectively. There is a trend toward more uniform use of antibiotics and steroids in the perioperative period. Neurologic infections (pooled prevalence 2.3%, 95% confidence interval 1.5–3.1), superficial infections (3.0%, 1.9–4.1), intracranial hemorrhage (4.0%, 3.2–4.8), and elevated intracranial pressure (2.4%, 1.5–3.3) were found to be the most common adverse events. Up to 3.5% of patients required additional surgical procedure(s) for management of these adverse events. Increased number of electrodes (≥67) was found to be independently associated with increased incidence of adverse events. Significance Although providing critical information for patients with medically refractory epilepsy, subdural grids implantation and invasive EEG monitoring entails risks of infection, hemorrhage, and elevated intracranial pressure. The prevalence estimates, likely to be conservative due to selective reporting, are expected to be helpful in counseling patients.

Tethered cord syndrome (TCS) is a clinical condition of various origins that arises from tension on the spinal cord. Radiographic findings may include the conus medullaris in a lower than normal position, fatty infiltration of the filum terminale, lipomyelomeningocele, myelomeningocele, myelocystocele, meningocele, split cord malformations, dermal sinus, anorectal malformations, and intraspinal tumors. The clinical constellation of signs and symptoms associated with TCS may include dermatologic, urological, gastrointestinal, neurological, and orthopedic findings. The current review focuses on TCS by age group of the more common causes of the condition, including myelomeningocele, lipomyelomeningocele, as well as the adult presentation of occult TCS. Pertinent review of the neuroembryology and normal anatomical position of the conus medullaris is included.

Objectives:To evaluate the diagnostic value of individual noninvasive presurgical modalities and to study their role in surgical management of nonlesional pediatric epilepsy patients. Methods:We retrospectively studied 14 children (3-18 years) Concordance of localization between each test and iEEG was scored as follows: 2 ϭ lobar concordance; 1 ϭ hemispheric concordance; 0 ϭ discordance or nonlocalization. Total concordance score in each patient was measured by the summation of concordance scores for all 3 tests.Results: Seven (50%) of 14 patients were seizure-free for at least 12 months after surgery. One (7%) had only rare seizures and 6 (43%) had persistent seizures. MEG (79%, 11/14) and SISCOM (79%, 11/14) showed greater lobar concordance with iEEG than SPM-PET (13%, 3/14) (p Ͻ 0.05). SPM-PET provided hemispheric lateralization (71%, 10/14) more often than lobar localization. Total concordance score tended to be greater for seizure-free patients (4.7) than for non-seizure-free patients (3.9). Children with medically intractable epilepsy have been considered for epilepsy surgery if the epileptogenic zone is reasonably localized with noninvasive presurgical evaluation. Conclusions:1-3 Among available noninvasive tests, the most accurate and reliable tool for identification of seizure focus remains MRI. Presence of visible MRI lesion not only warrants surgical candidacy, but also predicts a favorable surgical outcome.4-7 Recent advances with high-resolution MRI may reveal the presence of brain lesions not previously detected. However, some patients continue to have no detectable lesions on MRI, despite the suggestion of a focal epileptogenic zone on seizure semiology and scalp EEG.When no lesion is seen on MRI, other noninvasive functional imaging modalities have been employed: peri-ictal SPECT and subsequent subtraction image coregistered to MRI (SISCOM) may visualize increased blood flow at the time of seizure 8,9 ; 2-deoxy-2-( 18 F)fluoro-D-glucose PET (FDG-PET) and subsequent voxel-based analysis using statistical parametric mapping (SPM) may visualize the areas of decreased metabolism 10 ; and magnetoencephalography (MEG)/magnetic source localization (MSI) may reveal the source of interictal/ictal epileptic discharges.

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Summary Purpose Intracranial electroencephalography (EEG) is performed as part of an epilepsy surgery evaluation when noninvasive tests are incongruent or the putative seizure-onset zone is near eloquent cortex. Determining the seizure-onset zone using intracranial EEG has been conventionally based on identification of specific ictal patterns with visual inspection. High-frequency oscillations (HFOs, >80 Hz) have been recognized recently as highly correlated with the epileptogenic zone. However, HFOs can be difficult to detect because of their low amplitude. Therefore, the prevalence of ictal HFOs and their role in localization of epileptogenic zone on intracranial EEG are unknown. Methods We identified 48 patients who underwent surgical treatment after the surgical evaluation with intracranial EEG, and 44 patients met criteria for this retrospective study. Results were not used in surgical decision making. Intracranial EEG recordings were collected with a sampling rate of 2,000 Hz. Recordings were first inspected visually to determine ictal onset and then analyzed further with time-frequency analysis. Forty-one (93%) of 44 patients had ictal HFOs determined with time-frequency analysis of intracranial EEG. Key Findings Twenty-two (54%) of the 41 patients with ictal HFOs had complete resection of HFO regions, regardless of frequency bands. Complete resection of HFOs (n = 22) resulted in a seizure-free outcome in 18 (82%) of 22 patients, significantly higher than the seizure-free outcome with incomplete HFO resection (4/19, 21%). Significance Our study shows that ictal HFOs are commonly found with intracranial EEG in our population largely of children with cortical dysplasia, and have localizing value. The use of ictal HFOs may add more promising information compared to interictal HFOs because of the evidence of ictal propagation and followed by clinical aspect of seizures. Complete resection of HFOs is a favorable prognostic indicator for surgical outcome.

Placement of subdural grid and strip electrodes for invasive video electroencephalographic monitoring is generally well tolerated in the pediatric population. The authors found that aggressive initial electrode coverage was not associated with higher rates of blood transfusion or perioperative complications, and reduced the frequency of repeated operations for placement of supplemental electrodes.

Objective: We describe the development and evaluation of a system that uses machine learning and natural language processing techniques to identify potential candidates for surgical intervention for drug-resistant pediatric epilepsy. The data are comprised of free-text clinical notes extracted from the electronic health record (EHR). Both known clinical outcomes from the EHR and manual chart annotations provide gold standards for the patient’s status. The following hypotheses are then tested: 1) machine learning methods can identify epilepsy surgery candidates as well as physicians do and 2) machine learning methods can identify candidates earlier than physicians do. These hypotheses are tested by systematically evaluating the effects of the data source, amount of training data, class balance, classification algorithm, and feature set on classifier performance. The results support both hypotheses, with F-measures ranging from 0.71 to 0.82. The feature set, classification algorithm, amount of training data, class balance, and gold standard all significantly affected classification performance. It was further observed that classification performance was better than the highest agreement between two annotators, even at one year before documented surgery referral. The results demonstrate that such machine learning methods can contribute to predicting pediatric epilepsy surgery candidates and reducing lag time to surgery referral.

Pediatric hydrocephalus is characterized by an abnormal accumulation of cerebrospinal fluid (CSF) and is one of the most common congenital brain abnormalities. However, little is known about the molecular and cellular mechanisms regulating CSF flow in the developing brain. Through whole-genome sequencing analysis, we report that a homozygous splice site mutation in coiled-coil domain containing 39 () is responsible for early postnatal hydrocephalus in the () mouse mutant. is selectively expressed in embryonic choroid plexus and ependymal cells on the medial wall of the forebrain ventricle, and the protein is localized to the axoneme of motile cilia. The ependymal cells develop shorter cilia with disorganized microtubules lacking the axonemal inner arm dynein. Using high-speed video microscopy, we show that an orchestrated ependymal ciliary beating pattern controls unidirectional CSF flow on the ventricular surface, which generates bulk CSF flow in the developing brain. Collectively, our data provide the first evidence for involvement of in hydrocephalus and suggest that the proper development of medial wall ependymal cilia is crucial for normal mouse brain development.