The Interictal Suppression Hypothesis in focal epilepsy: network-level supporting evidence

Why are people with focal epilepsy not continuously having seizures? Previous neuronal signalling work has implicated gamma-aminobutyric acid balance as integral to seizure generation and termination, but is a high-level distributed brain network involved in suppressing seizures? Recent intracranial electrographic evidence has suggested that seizure-onset zones have increased inward connectivity that could be associated with interictal suppression of seizure activity. Accordingly, we hypothesize that seizure-onset zones are actively suppressed by the rest of the brain network during interictal states. Full testing of this hypothesis would require collaboration across multiple domains of neuroscience. We focused on partially testing this hypothesis at the electrographic network level within 81 individuals with drug-resistant focal epilepsy undergoing presurgical evaluation. We used intracranial electrographic resting-state and neurostimulation recordings to evaluate the network connectivity of seizure onset, early propagation and non-involved zones. We then used diffusion imaging to acquire estimates of white-matter connectivity to evaluate structure-function coupling effects on connectivity findings. Finally, we generated a resting-state classification model to assist clinicians in detecting seizure-onset and propagation zones without the need for multiple ictal recordings. Our findings indicate that seizure onset and early propagation zones demonstrate markedly increased inwards connectivity and decreased outwards connectivity using both resting-state (one-way ANOVA, P-value = 3.13 × 10-13) and neurostimulation analyses to evaluate evoked responses (one-way ANOVA, P-value = 2.5 × 10-3). When controlling for the distance between regions, the difference between inwards and outwards connectivity remained stable up to 80 mm between brain connections (two-way repeated measures ANOVA, group effect P-value of 2.6 × 10-12). Structure-function coupling analyses revealed that seizure-onset zones exhibit abnormally enhanced coupling (hypercoupling) of surrounding regions compared to presumably healthy tissue (two-way repeated measures ANOVA, interaction effect P-value of 9.76 × 10-21). Using these observations, our support vector classification models achieved a maximum held-out testing set accuracy of 92.0 ± 2.2% to classify early propagation and seizure-onset zones. These results suggest that seizure-onset zones are actively segregated and suppressed by a widespread brain network. Furthermore, this electrographically observed functional suppression is disproportionate to any observed structural connectivity alterations of the seizure-onset zones. These findings have implications for the identification of seizure-onset zones using only brief electrographic recordings to reduce patient morbidity and augment the presurgical evaluation of drug-resistant epilepsy. Further testing of the interictal suppression hypothesis can provide insight into potential new resective, ablative and neuromodulation approaches to improve surgical success rates in those suffering from drug-resistant focal epilepsy.

Treatment of hydrocephalus following posterior fossa tumor resection: a multicenter collaboration from the Hydrocephalus Clinical Research Network

OBJECTIVE

Persistent hydrocephalus following posterior fossa brain tumor (PFBT) resection is a common cause of morbidity in pediatric brain tumor patients, for which the optimal treatment is debated. The purpose of this study was to compare treatment outcomes between VPS and ETV in patients with persistent hydrocephalus following surgical resection of a PFBT.

METHODS

A post-hoc analysis was performed of the Hydrocephalus Clinical Research Network (HCRN) prospective observational study evaluating VPS and ETV for pediatric patients. Children who experienced hydrocephalus secondary to PFBT from 2008 to 2021 were included. Primary outcomes were VPS/ETV treatment failure and time-to-failure (TTF).

RESULTS

Among 241 patients, the VPS (183) and ETV (58) groups were similar in age, extent of tumor resection, and preoperative ETV Success Score. There was no difference in overall treatment failure between VPS and ETV (33.9% vs 31.0%, p = 0.751). However, mean TTF was shorter for ETV than VPS (0.45 years vs 1.30 years, p = 0.001). While major complication profiles were similar, compared to VPS, ETV patients had relatively higher incidence of minor CSF leak (10.3% vs. 1.1%, p = 0.003) and pseudomeningocele (12.1% vs 3.3%, p = 0.02). No ETV failures were identified beyond 3 years, while shunt failures occurred beyond 5 years. Shunt infections occurred in 5.5% of the VPS cohort.

CONCLUSIONS

ETV and VPS offer similar overall success rates for PFBT-related postoperative hydrocephalus. ETV failure occurs earlier, while susceptibility to VPS failure persists beyond 5 years. Tumor histology and grade may be considered when selecting the optimal means of CSF diversion.

Multi-Center Validation of the McGovern Pediatric Blunt Cerebrovascular Injury Screening Score

Blunt cerebrovascular injury (BCVI) is defined as blunt trauma to the head and neck leading to damage to the vertebral and/or carotid arteries; debate exists regarding which children are considered at high risk for BCVI and in need of angiographic/vessel imaging. We previously proposed a screening tool, the McGovern score, to identify pediatric trauma patients at high risk for BCVI, and we aim to validate the McGovern score by pooling data from multiple pediatric trauma centers. This is a multi-center, hospital-based, cohort study from all prospectively registered pediatric (<16 years of age) trauma patients who presented to the emergency department (ED) between 2003 and 2017 at six Level 1 pediatric trauma centers. The registry was retrospectively queried for patients who received a computed tomography angiogram (CTA) as a screening method for BCVI. Age, length of follow-up, mechanism of injury (MOI), arrival Glasgow Coma Scale (GCS) score, and focal neurological deficit were recorded. Radiological variables queried were the presence of a carotid canal fracture, petrous temporal bone fracture, and CT presence of infarction. Patients with BCVI were queried for mode of treatment, type of intracranial injury, artery damaged, and BCVI injury grade. The McGovern score was calculated for all patients who underwent CTA across all data groups. A total of 1012 patients underwent CTA; 72 of these patients were found to have BCVI, 51 of which were in the validation cohort. Across all data groups, the McGovern score has a >80% sensitivity (SN) and >98% negative predictive value (NPV). The McGovern score for pediatric BCVI is an effective, generalizable screening tool.

Endoscopic third ventriculostomy in previously shunt-treated patients

OBJECTIVE

Endoscopic third ventriculostomy (ETV) is an option for treatment of hydrocephalus, including for patients who have a history of previous treatment with CSF shunt insertion. The purpose of this study was to report the success of postshunt ETV by using data from a multicenter prospective registry.

METHODS

Prospectively collected data in the Hydrocephalus Clinical Research Network (HCRN) Core Data Project (i.e., HCRN Registry) were reviewed. Children who underwent ETV between 2008 and 2019 and had a history of previous treatment with a CSF shunt were included. A Kaplan-Meier survival curve was created for the primary outcome: time from postshunt ETV to subsequent CSF shunt placement or revision. Univariable Cox proportional hazards models were created to evaluate for an association between clinical and demographic variables and subsequent shunt surgery. Postshunt ETV complications were also identified and categorized.

RESULTS

A total of 203 children were included: 57% male and 43% female; 74% White, 23% Black, and 4% other race. The most common hydrocephalus etiologies were postintraventricular hemorrhage secondary to prematurity (56, 28%) and aqueductal stenosis (42, 21%). The ETV Success Score ranged from 10 to 80. The median patient age was 4.1 years. The overall success of postshunt ETV at 6 months was 41%. Only the surgeon's report of a clear view of the basilar artery was associated with a lower likelihood of postshunt ETV failure (HR 0.43, 95% CI 0.23-0.82, p = 0.009). None of the following variables were associated with postshunt ETV success: age at the time of postshunt ETV, etiology of hydrocephalus, sex, race, ventricle size, number of previous shunt operations, ETV performed at time of shunt infection, and use of external ventricular drainage. Overall, complications were reported in 22% of patients, with CSF leak (8.6%) being the most common complication.

CONCLUSIONS

Postshunt ETV was successful in treating hydrocephalus, without subsequent need for a CSF shunt, in 41% of patients, with a clear view of the basilar artery being the only variable significantly associated with success. Complications occurred in 22% of patients. ETV is an option for treatment of hydrocephalus in children who have previously undergone shunt placement, but with a lower than expected likelihood of success.

Endoscopic third ventriculostomy revision after failure of initial endoscopic third ventriculostomy and choroid plexus cauterization

OBJECTIVE

Primary treatment of hydrocephalus with endoscopic third ventriculostomy (ETV) and choroid plexus cauterization (CPC) is well described in the neurosurgical literature, with wide reported ranges of success and complication rates. The purpose of this study was to describe the safety and efficacy of ETV revision after initial ETV+CPC failure.

METHODS

Prospectively collected data in the Hydrocephalus Clinical Research Network Core Data Project registry were reviewed. Children who underwent ETV+CPC as the initial treatment for hydrocephalus between 2013 and 2019 and in whom the initial ETV+CPC was completed (i.e., not abandoned) were included. Log-rank survival analysis (the primary analysis) was used to compare time to failure (defined as any other surgical treatment for hydrocephalus or death related to hydrocephalus) of initial ETV+CPC versus that of ETV revision by using random-effects modeling to account for the inclusion of patients in both the initial and revision groups. Secondary analysis compared ETV revision to shunt placement after failure of initial ETV+CPC by using the log-rank test, as well as shunt failure after ETV+CPC to that after ETV revision. Cox regression analysis was used to identify predictors of failure among children treated with ETV revision.

RESULTS

The authors identified 521 ETV+CPC procedures that met their inclusion criteria. Ninety-one children underwent ETV revision after ETV+CPC failure. ETV revision had a lower 1-year success rate than initial ETV+CPC (29.5% vs 45%, p < 0.001). ETV revision after initial ETV+CPC failure had a lower success rate than shunting (29.5% vs 77.8%, p < 0.001). Shunt survival after initial ETV+CPC failure was not significantly different from shunt survival after ETV revision failure (p = 0.963). Complication rates were similar for all examined surgical procedures (initial ETV+CPC, ETV revision, ventriculoperitoneal shunt [VPS] placement after ETV+CPC, and VPS placement after ETV revision). Only young age was predictive of ETV revision failure (p = 0.02).

CONCLUSIONS

ETV revision had a significantly lower 1-year success rate than initial ETV+CPC and VPS placement after ETV+CPC. Complication rates were similar for all studied procedures. Younger age, but not time since initial ETV+CPC, was a risk factor for ETV revision failure.

SEEG Functional Connectivity Measures to Identify Epileptogenic Zones: Stability, Medication Influence, and Recording Condition

BACKGROUND AND OBJECTIVES

Functional connectivity (FC) measures can be used to differentiate epileptogenic zones (EZs) from non-EZs in patients with medically refractory epilepsy. Little work has been done to evaluate the stability of stereo-EEG (SEEG) FC measures over time and their relationship with antiseizure medication (ASM) use, a critical confounder in epilepsy FC studies. We aimed to answer the following questions: Are SEEG FC measures stable over time? Are they influenced by ASMs? Are they affected by patient data collection state?

METHODS

In 32 patients with medically refractory focal epilepsy, we collected a single 2-minute prospective SEEG resting-state (awake, eyes closed) data set and consecutive 2-minute retrospective pseudo-rest (awake, eyes open) data sets for days 1-7 postimplantation. ASM dosages were recorded for days 1-7 postimplantation and drug load score (DLS) per day was calculated to standardize and compare across patients. FC was evaluated using directed and nondirected measures. Standard clinical interpretation of ictal SEEG was used to classify brain regions as EZs and non-EZs.

RESULTS

Over 7 days, presumed EZs consistently had higher FC than non-EZs when using between imaginary coherence (ImCoh) and partial directed coherence (PDC) inward strength, without accounting for DLS. These measures were demonstrated to be stable over a short-term period of 3 consecutive days with the same DLS. Between ImCoh FC differences between EZs and non-EZs were reduced with DLS decreases, whereas other measures were not affected by DLS. FC differences between EZs and non-EZs were seen during both resting-state and pseudo-rest conditions; ImCoh values were strongly correlated between the 2 conditions, whereas PDC values were not.

DISCUSSION

Inward and nondirected SEEG FC is higher in presumed EZs vs non-EZs and measures are stable over time. However, certain measures may be affected by ASM dose, as between ImCoh differences between EZs and non-EZs are less pronounced with lower doses, and other measures such as PDC are poorly correlated across recording conditions. These findings allow novel insight into how SEEG FC measures may aid surgical localization and how they are influenced by ASMs and other factors.

The Hydrocephalus Clinical Research Network quality improvement initiative: the role of antibiotic-impregnated catheters and vancomycin wound irrigation

OBJECTIVE

Two previous Hydrocephalus Clinical Research Network (HCRN) studies have demonstrated that compliance with a standardized CSF shunt infection protocol reduces shunt infections. In this third iteration, a simplified protocol consisting of 5 steps was implemented. This analysis provides an updated evaluation of protocol compliance and evaluates modifiable shunt infection risk factors.

METHODS

The new simplified protocol was implemented at HCRN centers on November 1, 2016, for all shunt procedures, excluding external ventricular drains, ventricular reservoirs, and subgaleal shunts. Procedures performed through December 31, 2019, were included (38 months). Compliance with the protocol, use of antibiotic-impregnated catheters (AICs), and other variables of interest were collected at the index operation. Outcome events for a minimum of 6 months postoperatively were recorded. The definition of infection was unchanged from the authors' previous report.

RESULTS

A total of 4913 procedures were performed at 13 HCRN centers. The overall infection rate was 5.1%. Surgeons were compliant with all 5 steps of the protocol in 79.4% of procedures. The infection rate for the protocol alone was 8.1% and dropped to 4.9% when AICs were added. Multivariate analysis identified having ≥ 2 complex chronic conditions (odds ratio [OR] 1.76, 95% confidence interval [CI] 1.26-2.44, p = 0.01) and a history of prior shunt surgery within 12 weeks (OR 1.84, 95% CI 1.37-2.47, p < 0.01) as independent risk factors for shunt infection. The use of AICs (OR 0.70, 95% CI 0.50-0.97, p = 0.05) and vancomycin irrigation (OR 0.36, 95% CI 0.21-0.62, p < 0.01) were identified as independent factors protective against shunt infection.

CONCLUSIONS

The authors report the third iteration of their quality improvement protocol to reduce the risk of shunt infection. Compliance with the protocol was high. These updated data suggest that the incorporation of AICs is an important, modifiable infection prevention measure. Vancomycin irrigation was also identified as a protective factor but requires further study to better understand its role in preventing shunt infection.

Targeting Epilepsy Through the Foremen Ovale: How Many Helical Needles are Needed?

Laser ablation of the hippocampus offers medically refractory epilepsy patients an alternative to invasive surgeries. Emerging commercial solutions deliver the ablator through a burr hole in the back of the head. We recently introduced a new access path through the foremen ovale, using a helical needle, which minimizes the amount of healthy brain tissue the needle must pass through on its way to the hippocampus, and also enables the needle to follow the medial axis of the hippocampus more closely. In this paper, we investigate whether helical needles should be designed and fabricated on a patient-specific basis as we had previously proposed, or whether a small collection of pre-defined needle shapes can apply across many patients. We propose a new optimization strategy to determine this needle set using patient data, and investigate the accuracy with which these needles can reach the the medial axis of the hippocampus. We find that three basic tube shapes (mirrored as necessary for left vs. right hippocampi) are all that is required, across 20 patient datasets (obtained from 10 patient CT scans), to reduce worst-case maximum error below 2 mm.

Anterior versus posterior entry site for ventriculoperitoneal shunt insertion: a randomized controlled trial by the Hydrocephalus Clinical Research Network

OBJECTIVE

The primary objective of this trial was to determine if shunt entry site affects the risk of shunt failure.

METHODS

The authors performed a parallel-design randomized controlled trial with an equal allocation of patients who received shunt placement via the anterior entry site and patients who received shunt placement via the posterior entry site. All patients were children with symptoms or signs of hydrocephalus and ventriculomegaly. Patients were ineligible if they had a prior history of shunt insertion. Patients received a ventriculoperitoneal shunt after randomization; randomization was stratified by surgeon. The primary outcome was shunt failure. The planned minimum follow-up was 18 months. The trial was designed to achieve high power to detect a 10% or greater absolute difference in the shunt failure rate at 1 year. An independent, blinded adjudication committee determined eligibility and the primary outcome. The study was conducted by the Hydrocephalus Clinical Research Network.

RESULTS

The study randomized 467 pediatric patients at 14 tertiary care pediatric hospitals in North America from April 2015 to January 2019. The adjudication committee, blinded to intervention, excluded 7 patients in each group for not meeting the study inclusion criteria. For the primary analysis, there were 229 patients in the posterior group and 224 patients in the anterior group. The median patient age was 1.3 months, and the most common etiologies of hydrocephalus were postintraventricular hemorrhage secondary to prematurity (32.7%), myelomeningocele (16.8%), and aqueductal stenosis (10.8%). There was no significant difference in the time to shunt failure between the entry sites (log-rank test, stratified by age < 6 months and ≥ 6 months; p = 0.061). The hazard ratio (HR) of a posterior shunt relative to an anterior shunt was calculated using a univariable Cox regression model and was nonsignificant (HR 1.35, 95% CI, 0.98-1.85; p = 0.062). No significant difference was found between entry sites for the surgery duration, number of ventricular catheter passes, ventricular catheter location, and hospital length of stay. There were no significant differences between entry sites for intraoperative complications, postoperative CSF leaks, pseudomeningoceles, shunt infections, skull fractures, postoperative seizures, new-onset epilepsy, or intracranial hemorrhages.

CONCLUSIONS

This randomized controlled trial comparing the anterior and posterior shunt entry sites has demonstrated no significant difference in the time to shunt failure. Anterior and posterior entry site surgeries were found to have similar outcomes and similar complication rates.

Measuring the effects of institutional pediatric traumatic brain injury volume on outcomes for rural-dwelling children

OBJECTIVE

Rural-dwelling children may suffer worse pediatric traumatic brain injury (TBI) outcomes due to distance from and accessibility to high-volume trauma centers. This study aimed to compare the impacts of institutional TBI volume and sociodemographics on outcomes between rural- and urban-dwelling children.

METHODS

This retrospective study identified patients 0-19 years of age with ICD-9 codes for TBI in the 2012-2015 National Inpatient Sample database. Patients were characterized as rural- or urban-dwelling using United States Census classification. Logistic and linear (in log scale) regressions were performed to measure the effects of institutional characteristics, patient sociodemographics, and mechanism/severity of injury on occurrence of medical complications, mortality, length of stay (LOS), and costs. Separate models were built for rural- and urban-dwelling patients.

RESULTS

A total of 19,736 patients were identified (median age 11 years, interquartile range [IQR] 2-16 years, 66% male, 55% Caucasian). Overall, rural-dwelling patients had higher All Patient Refined Diagnosis Related Groups injury severity (median 2 [IQR 1-3] vs 1 [IQR 1-2], p < 0.001) and more intracranial monitoring (6% vs 4%, p < 0.001). Univariate analysis showed that overall, rural-dwelling patients suffered increased medical complications (6% vs 4%, p < 0.001), mortality (6% vs 4%, p < 0.001), and LOS (median 2 days [IQR 1-4 days ] vs 2 days [IQR 1-3 days], p < 0.001), but multivariate analysis showed rural-dwelling status was not associated with these outcomes after adjusting for injury severity, mechanism, and hospital characteristics. Institutional TBI volume was not associated with medical complications, disposition, or mortality for either population but was associated with LOS for urban-dwelling patients (nonlinear beta, p = 0.008) and cost for both rural-dwelling (nonlinear beta, p < 0.001) and urban-dwelling (nonlinear beta, p < 0.001) patients.

CONCLUSIONS

Overall, rural-dwelling pediatric patients with TBI have worsened injury severity, mortality, and in-hospital complications, but these disparities disappear after adjusting for injury severity and mechanism. Institutional TBI volume does not impact clinical outcomes for rural- or urban-dwelling children after adjusting for these covariates. Addressing the root causes of the increased injury severity at hospital arrival may be a useful path to improve TBI outcomes for rural-dwelling children.

Choice and Trade-offs: Parent Decision Making for Neurotechnologies for Pediatric Drug-Resistant Epilepsy

This qualitative study investigated factors that guide caregiver decision making and ethical trade-offs for advanced neurotechnologies used to treat children with drug-resistant epilepsy. Caregivers with affected children were recruited to semi-structured focus groups or interviews at one of 4 major epilepsy centers in Eastern and Western Canada and the USA (n = 22). Discussions were transcribed and qualitative analytic methods applied to examine values and priorities (eg, risks, benefits, adherence, invasiveness, reversibility) of caregivers pertaining to novel technologies to treat drug-resistant epilepsy. Discussions revealed 3 major thematic branches for decision making: (1) features of the intervention-risks and benefits, with an emphasis on an aversion to perceived invasiveness; (2) decision drivers-trust in the clinical team, treatment costs; and (3) quality of available information about neurotechnological options. Overall, caregivers' definition of treatment success is more expansive than seizure freedom. The full involvement of their values and priorities must be considered in the decision-making process.

Genome-Wide Association Study Identifies Genetic Risk Factors for Spastic Cerebral Palsy

BACKGROUND

Although many clinical risk factors of spastic cerebral palsy (CP) have been identified, the genetic basis of spastic CP is largely unknown. Here, using whole-genome genetic information linked to a deidentified electronic health record (BioVU) with replication in the UK Biobank and FinnGen, we perform the first genome-wide association study (GWAS) for spastic CP.

OBJECTIVE

To define the genetic basis of spastic CP.

METHODS

Whole-genome data were obtained using the multi-ethnic genotyping array (MEGA) genotyping array capturing single-nucleotide polymorphisms (SNPs), minor allele frequency (MAF) > 0.01, and imputation quality score (r2) > 0.3, imputed based on the 1000 genomes phase 3 reference panel. Threshold for genome-wide significance was defined after Bonferroni correction for the total number of SNPs tested (P < 5.0 × 10-8). Replication analysis (defined as P < .05) was performed in the UK Biobank and FinnGen.

RESULTS

We identify 1 SNP (rs78686911) reaching genome-wide significance with spastic CP. Expression quantitative trait loci (eQTL) analysis suggests that rs78686911 decreases expression of GRIK4, a gene that encodes a high-affinity kainate glutamatergic receptor of largely unknown function. Replication analysis in the UK Biobank and FinnGen reveals additional SNPs in the GRIK4 loci associated with CP.

CONCLUSION

To our knowledge, we perform the first GWAS of spastic CP. Our study indicates that genetic variation contributes to CP risk.

Longitudinal CSF Iron Pathway Proteins in Posthemorrhagic Hydrocephalus: Associations with Ventricle Size and Neurodevelopmental Outcomes

OBJECTIVE

Iron has been implicated in the pathogenesis of brain injury and hydrocephalus after preterm germinal matrix hemorrhage-intraventricular hemorrhage, however, it is unknown how external or endogenous intraventricular clearance of iron pathway proteins affect the outcome in this group.

METHODS

This prospective multicenter cohort included patients with posthemorrhagic hydrocephalus (PHH) who underwent (1) temporary and permanent cerebrospinal fluid (CSF) diversion and (2) Bayley Scales of Infant Development-III testing around 2 years of age. CSF proteins in the iron handling pathway were analyzed longitudinally and compared to ventricle size and neurodevelopmental outcomes.

RESULTS

Thirty-seven patients met inclusion criteria with a median estimated gestational age at birth of 25 weeks; 65% were boys. Ventricular CSF levels of hemoglobin, iron, total bilirubin, and ferritin decreased between temporary and permanent CSF diversion with no change in CSF levels of ceruloplasmin, transferrin, haptoglobin, and hepcidin. There was an increase in CSF hemopexin during this interval. Larger ventricle size at permanent CSF diversion was associated with elevated CSF ferritin (p = 0.015) and decreased CSF hemopexin (p = 0.007). CSF levels of proteins at temporary CSF diversion were not associated with outcome, however, higher CSF transferrin at permanent CSF diversion was associated with improved cognitive outcome (p = 0.015). Importantly, longitudinal change in CSF iron pathway proteins, ferritin (decrease), and transferrin (increase) were associated with improved cognitive (p = 0.04) and motor (p = 0.03) scores and improved cognitive (p = 0.04), language (p = 0.035), and motor (p = 0.008) scores, respectively.

INTERPRETATION

Longitudinal changes in CSF transferrin (increase) and ferritin (decrease) are associated with improved neurodevelopmental outcomes in neonatal PHH, with implications for understanding the pathogenesis of poor outcomes in PHH. ANN NEUROL 2021;90:217-226.

Machine learning predicts risk of cerebrospinal fluid shunt failure in children: a study from the hydrocephalus clinical research network

PURPOSE

While conventional statistical approaches have been used to identify risk factors for cerebrospinal fluid (CSF) shunt failure, these methods may not fully capture the complex contribution of clinical, radiologic, surgical, and shunt-specific variables influencing this outcome. Using prospectively collected data from the Hydrocephalus Clinical Research Network (HCRN) patient registry, we applied machine learning (ML) approaches to create a predictive model of CSF shunt failure.

METHODS

Pediatric patients (age < 19 years) undergoing first-time CSF shunt placement at six HCRN centers were included. CSF shunt failure was defined as a composite outcome including requirement for shunt revision, endoscopic third ventriculostomy, or shunt infection within 5 years of initial surgery. Performance of conventional statistical and 4 ML models were compared.

RESULTS

Our cohort consisted of 1036 children undergoing CSF shunt placement, of whom 344 (33.2%) experienced shunt failure. Thirty-eight clinical, radiologic, surgical, and shunt-design variables were included in the ML analyses. Of all ML algorithms tested, the artificial neural network (ANN) had the strongest performance with an area under the receiver operator curve (AUC) of 0.71. The ANN had a specificity of 90% and a sensitivity of 68%, meaning that the ANN can effectively rule-in patients most likely to experience CSF shunt failure (i.e., high specificity) and moderately effective as a tool to rule-out patients at high risk of CSF shunt failure (i.e., moderately sensitive). The ANN was independently validated in 155 patients (prospectively collected, retrospectively analyzed).

CONCLUSION

These data suggest that the ANN, or future iterations thereof, can provide an evidence-based tool to assist in prognostication and patient-counseling immediately after CSF shunt placement.

Treatment strategies for hydrocephalus related to Dandy-Walker syndrome: evaluating procedure selection and success within the Hydrocephalus Clinical Research Network

OBJECTIVE

Treating Dandy-Walker syndrome-related hydrocephalus (DWSH) involves either a CSF shunt-based or endoscopic third ventriculostomy (ETV)-based procedure. However, comparative investigations are lacking. This study aimed to compare shunt-based and ETV-based treatment strategies utilizing archival data from the Hydrocephalus Clinical Research Network (HCRN) registry.

METHODS

A retrospective review of prospectively collected and maintained data on children with DWSH, available from the HCRN registry (14 sites, 2008-2018), was performed. The primary outcome was revision-free survival of the initial surgical intervention. The primary exposure was either shunt-based (i.e., cystoperitoneal shunt [CPS], ventriculoperitoneal shunt [VPS], and/or dual-compartment) or ETV-based (i.e., ETV alone or with choroid plexus cauterization [CPC]) initial surgical treatment. Primary analysis included multivariable Cox proportional hazards models.

RESULTS

Of 8400 HCRN patients, 151 (1.8%) had DWSH. Among these, the 102 patients who underwent shunt placement (79 VPSs, 16 CPSs, 3 other, and 4 multiple proximal catheter) were younger (6.6 vs 18.8 months, p < 0.001) and more frequently had 1 or more comorbidities (37.3% vs 14.3%, p = 0.005) than the 49 ETV-treated children (28 ETV-CPC). Fifty percent of the shunt-based and 51% of the ETV-based treatments failed. Notably, 100% (4/4) of the dual-compartment shunts failed. Adjusting for age, baseline ventricular size, and comorbidities, ETV-based treatment was not significantly associated with earlier failure compared with shunt-based treatment (HR for failure 1.32, 95% CI 0.77-2.26; p = 0.321). Complication rates were low: 4.9% and 6.1% (p = 0.715) for shunt- and ETV-based procedures, respectively. There was no difference in survival between ETV-CPC- and ETV-based treatment when adjusting for age (HR for failure 0.86, 95% CI 0.29-2.55, p = 0.783).

CONCLUSIONS

In this North American, multicenter, prospective database review, shunt-based and ETV-based primary treatment strategies of DWSH appear similarly durable. Pediatric neurosurgeons can reasonably consider ETV-based initial treatment given the similar durability and the low complication rate. However, given the observational nature of this study, the treating surgeon might need to consider subgroups that were too small for a separate analysis. Very young children with comorbidities were more commonly treated with shunts, and older children with fewer comorbidities were offered ETV-based treatment. Future studies may determine preoperative characteristics associated with ETV treatment success in this population.

Novel Neurotechnological Interventions for Pediatric Drug-Resistant Epilepsy: Physician Perspectives

This qualitative study investigated factors that guide physicians' choices for minimally invasive and neuromodulatory interventions as alternatives to conventional surgery or medical management for pediatric drug-resistant epilepsy. North American physicians were recruited to one of 4 focus groups at national conferences. Discussions were analyzed using qualitative content analysis. A pragmatic neuroethics framework was applied to interpret results. Discussions revealed 2 major thematic branches: (1) clinical decision making and (2) ethical considerations. Under clinical decision making, physicians emphasized scientific evidence and patient candidacy when assessing neurotechnologies for patients. Ongoing seizures without intervention was important for safety and neurodevelopment. Under ethical considerations, resource allocation, among other financial considerations for technology adoption, were considerable sources of pressure on decision making. Access to neurotechnology was a salient theme differentiating Canadian and American contexts. When assessing novel neurotechnological interventions for pediatric drug-resistant epilepsy, physicians balance clinical and ethical factors to guide decision making and best practice.

The survival of reimplanted shunts following externalization: a single-institution cohort study

OBJECTIVE

The failure-free survival of ventriculoperitoneal shunts (VPSs) following externalization for distal catheter infection or malfunction has not been adequately explored. Conversion to a ventriculoatrial shunt (VAS) may allow earlier reinternalization in lieu of waiting for the peritoneum to be suitable for reimplantation. This option is tempered by historical concerns regarding high rates of VAS failure, and the risks of rare complications are rampant.

METHODS

In this retrospective cohort study, all patients undergoing externalization of a VPS at a single institution between 2005 and 2020 were grouped according to the new distal catheter terminus location at the time of reinternalization (VPS vs VAS). The primary outcomes were failure-free shunt survival and duration of shunt externalization. Secondary outcomes included early (< 6 months) shunt failure.

RESULTS

Among 36 patients, 43 shunt externalization procedures were performed. Shunts were reinternalized as VPSs in 25 cases and VASs in 18 cases. The median failure-free survival was 1002 (interquartile range [IQR] 161-3449) days for VPSs and 1163 (IQR 360-2927) days for VASs. There was no significant difference in shunt survival according to the new distal catheter terminus (log-rank, p = 0.73). Conversion to a VAS was not associated with shorter duration of shunt externalization (Wilcoxon rank-sum, p = 0.64); the median duration was 7 (IQR 5-11) days for VPSs and 8 (IQR 6-15) days for VASs. No rare complications occurred in the VAS group.

CONCLUSIONS

Shunt failure-free survival rates following externalization are similar to published survival rates for nonexternalized shunts. There was no significant difference in survival between reinternalized VPSs and VASs. Although the VAS was not associated with a shortened duration of externalization, this finding is confounded by strong institutional preference for the VPS over the VAS. Early conversion to the VAS may be a viable treatment option in light of reassuring modern VAS survival data.

Comparison of anticoagulation and antiplatelet therapy for treatment of blunt cerebrovascular injury in children <10 years of age: a multicenter retrospective cohort study

PURPOSE

Blunt cerebrovascular injury (BCVI) is uncommon in the pediatric population. Among the management options is medical management consisting of antithrombotic therapy with either antiplatelets or anticoagulation. There is no consensus on whether administration of antiplatelets or anticoagulation is more appropriate for BCVI in children < 10 years of age. Our goal was to compare radiographic and clinical outcomes based on medical treatment modality for BCVI in children < 10 years.

METHODS

Clinical and radiographic data were collected retrospectively for children screened for BCVI with computed tomography angiography at 5 academic pediatric trauma centers.

RESULTS

Among 651 patients evaluated with computed tomography angiography to screen for BCVI, 17 patients aged less than 10 years were diagnosed with BCVI (7 grade I, 5 grade II, 1 grade III, 4 grade IV) and received anticoagulation or antiplatelet therapy for 18 total injuries: 11 intracranial carotid artery, 4 extracranial carotid artery, and 3 extracranial vertebral artery injuries. Eleven patients were treated with antiplatelets (10 aspirin, 1 clopidogrel) and 6 with anticoagulation (4 unfractionated heparin, 2 low-molecular-weight heparin, 1 transitioned from the former to the latter). There were no complications secondary to treatment. One patient who received anticoagulation died as a result of the traumatic injuries. In aggregate, children treated with antiplatelet therapy demonstrated healing on 52% of follow-up imaging studies versus 25% in the anticoagulation cohort.

CONCLUSION

There were no observed differences in the rate of hemorrhagic complications between anticoagulation and antiplatelet therapy for BCVI in children < 10 years, with a nonsignificantly better rate of healing on follow-up imaging in children who underwent antiplatelet therapy; however, the study cohort was small despite including patients from 5 hospitals.

Pediatric Intrathecal Baclofen Pumps: A Descriptive Analysis of Hospital Course and Associated Costs

INTRODUCTION

The purpose of this study was to identify predictors of increased cost and postoperative length-of-stay (LOS) following intrathecal baclofen pump (ITBP) placement.

METHODS

Patients were derived from the 2009/2012 kids' inpatient database. Inclusion criteria were selected for patients with ICD-9 codes 343.X (infantile cerebral palsy), 86.06 (infusion pump insertion), 03.90 (spinal catheter insertion), and elective hospitalizations. Nonparametric univariate analysis and subsequent gamma log-link general linear modeling were used to identify significant predictors of cost/LOS (p < 0.05).

RESULTS

529 unweighted patients (787 with survey weights applied) met criteria. Median LOS was 3.00 days, and median cost was USD 23,284. Following multivariate modeling, predictors of increased LOS (in days) included increased hospital ITBP volume (p = 0.027), small hospital size (+0.55, p = 0.004), device complications (+0.95, p < 0.001), procedural complications (+1.40, p < 0.001), additional procedures (+0.86, p < 0.001), electrolyte abnormalities (+3.74, p < 0.001), and neurological comorbidities (+1.60, p < 0.001). Factors associated with decreased LOS were paralysis (-0.53, p < 0.001), Northeastern hospital region (-0.55, p = 0.018), and investor-owned hospital status (-0.75, p = 0.001). Similarly, predictors of increased cost included race of Hispanic (+USD 1,156, p = 0.033) or "other" (+USD 2,158, p = 0.001), Northeast hospital region (+USD 4,120, p < 0.001), small (+USD 4,139, p < 0.001) or medium (+USD 3,368, p < 0.001) hospital sizes, additional procedures (+USD 1,649, p < 0.001), neurological comorbidities (+USD 3,222, p = 0.003), and increased LOS (p < 0.001). Factors associated with decreased cost included Western hospital region (-USD 1,594, p = 0.001), government hospitals (-USD 1,391, p = 0.019), and investor-owned hospitals (-USD 2,057, p = 0.021).

CONCLUSION

This study found multiple variables associated with increased cost/LOS following ITBP placement. Broadly, this analysis demonstrates national trends associated with increased cost following ITBP placement.

Predictors of fast and ultrafast shunt failure in pediatric hydrocephalus: a Hydrocephalus Clinical Research Network study

OBJECTIVE

The primary objective of this study was to use the prospective Hydrocephalus Clinical Research Network (HCRN) registry to determine clinical predictors of fast time to shunt failure (≤ 30 days from last revision) and ultrafast time to failure (≤ 7 days from last revision).

METHODS

Revisions (including those due to infection) to permanent shunt placements that occurred between April 2008 and November 2017 for patients whose entire shunt experience was recorded in the registry were analyzed. All registry data provided at the time of initial shunt placement and subsequent revision were reviewed. Key variables analyzed included etiology of hydrocephalus, age at time of initial shunt placement, presence of slit ventricles on imaging at revision, whether the ventricles were enlarged at the time of revision, and presence of prior fast failure events. Univariable and multivariable analyses were performed to find key predictors of fast and ultrafast failure events.

RESULTS

A cohort of 1030 patients with initial shunt insertions experienced a total of 1995 revisions. Of the 1978 revision events with complete records, 1216 (61.5%) shunts remained functional for more than 1 year, and 762 (38.5%) failed within 1 year of the procedure date. Of those that failed within 1 year, 423 (55.5%) failed slowly (31-365 days) and 339 (44.5%) failed fast (≤ 30 days). Of the fast failures, 131 (38.6%) were ultrafast (≤ 7 days). In the multivariable analysis specified a priori, etiology of hydrocephalus (p = 0.005) and previous failure history (p = 0.011) were independently associated with fast failure. Age at time of procedure (p = 0.042) and etiology of hydrocephalus (p = 0.004) were independently associated with ultrafast failure. These relationships in both a priori models were supported by the data-driven multivariable models as well.

CONCLUSIONS

Neither the presence of slit ventricle syndrome nor ventricular enlargement at the time of shunt failure appears to be a significant predictor of repeated, rapid shunt revisions. Age at the time of procedure, etiology of hydrocephalus, and the history of previous failure events seem to be important predictors of fast and ultrafast shunt failure. Further work is required to understand the mechanisms of these risk factors as well as mitigation strategies.

QOL-22. MACHINE-LEARNING INFERENCE MAY PREDICT QUALITY OF LIFE SUBGROUPS OF ADAMANTINOMATOUS CRANIOPHARYNGIOMA

BACKGROUND

Due to disease and/or treatment-related injury, such as hypothalamic, visual, and endocrine damage, quality of life (QoL) scores after childhood-onset Adamantinomatous Craniopharyngioma (ACP) are among the lowest of all pediatric brain tumors. Decision-making regarding management would be aided by more complete understanding of a patients likely QoL trajectory following intervention.

METHODS

We retrospectively analyzed caregiver and patient-reported QoL-instruments from the first 50 patients (ages 1–17 years at diagnosis) enrolled in the international Advancing Treatment for Pediatric Craniopharyngioma (ATPC) consortium. Surveys included 205 pediatric-relevant questions and were completed at diagnosis, and 1- and 12-months following diagnosis. Using Multiple Correspondence Analysis (MCA), these categorical QoL surveys were interrogated to identify time-dependent patient subgroups. Additionally, custom deep learning classifiers were developed using Google’s TensorFlow framework.

RESULTS

By representing QoL data in the reduced dimensionality of MCA-space, we identified QoL subgroups that either improved or declined over time. We assessed differential trends in QoL responses to identify variables that were subgroup specific (Kolmogorov-Smirnov p-value < 0.1; n=20). Additionally, our optimized deep learning classifier achieved a mean 5-fold cross-validation area under precision-recall curve score > 0.99 when classifying QoL subgroups at 12 month follow-up, using only baseline data.

CONCLUSIONs

This work demonstrates the existence of time-dependent QoL-based ACP subgroups that can be inferred at time-of-diagnosis via machine learning analyses of baseline survey responses. The ability to predict an ACP patient’s QoL trajectory affords caregivers valuable information that can be leveraged to maximize that patient’s psychosocial state and therefore improve overall therapy.

The interaction between parental concern and socioeconomic status in pediatric hydrocephalus management

OBJECTIVE

Parent or guardian involvement is implicit in the care of pediatric patients with hydrocephalus. Some parents and guardians are more engaged than others. The relationship between socioeconomic status (SES), the level of parental concern about their child's hydrocephalus management and future, and overall health status has not been clearly delineated. In this study, the authors sought to clarify this connection using hydrocephalus patient-reported health outcomes.

METHODS

This cross-sectional study included children with surgically managed hydrocephalus whose parent or guardian completed the validated Hydrocephalus Outcome Questionnaire (HOQ) and Hydrocephalus Concern Questionnaire for parents (HCQ-P) on a return visit to the pediatric neurosurgery clinic at Vanderbilt University Medical Center between 2016 and 2018. Patients were excluded if the questionnaires were not completed in full. The calculated Overall Health Score (OHS) was used to represent the child's global physical, emotional, cognitive, and social health. The HCQ-P was used to assess parental concern about their child. Type of insurance was a proxy for SES.

RESULTS

The HOQ and HCQ-P were administered and completed in full by 170 patient families. In the cohort, 91% of patients (n = 155) had shunt-treated hydrocephalus, and the remaining patients had undergone endoscopic third ventriculostomy. The mean (± SD) patient age was 12 ± 4 years. Half of the patients were male (n = 90, 53%), and most were Caucasian (n = 134, 79%). One in four patients lived in single-parent homes or with a designated guardian (n = 45, 26%). Public insurance and self-pay accounted for 38% of patients (n = 64), while the remaining 62% had private or military insurance. In general, parents with higher concern about their child's medical condition indicated that their son or daughter had a higher OHS (χ2 = 17.07, p < 0.001). Patients in families with a lower SES did not have different OHSs from those with a higher SES (χ2 = 3.53, p = 0.06). However, parents with a lower SES were more worried about management of their child's hydrocephalus and their child's future success (χ2 = 11.49, p < 0.001). In general, parents were not preoccupied with one particular aspect of their child's hydrocephalus management.

CONCLUSIONS

More engaged parents, regardless of their family's SES, reported a better OHS for their child. Parents with public or self-paid insurance were more likely to report higher concern about their child's hydrocephalus and future, but this was not associated with a difference in their child's current health status.

Conus-level combined dorsal and ventral lumbar rhizotomy for treatment of mixed hypertonia: technical note and complications

Combined dorsal and ventral rhizotomy is an effective treatment for patients with concurrent spasticity and dystonia, with the preponderance of complaints relating to their lower extremities. This operative approach provides definitive relief of hypertonia and should be considered after less-invasive techniques have been exhausted. Previously, the surgery has been described through an L1-S1 laminoplasty. In this series, 7 patients underwent a conus-level laminectomy for performing a lumbar dorsal and ventral rhizotomy. Technical challenges included identifying the appropriate-level ventral roots and performing the procedure in children with significant scoliosis. Techniques are described to overcome these obstacles. The technique was found to be safe, with no infections, CSF leaks, or neurogenic bladders.

Tracking the Volume of Neurosurgical Care During the Coronavirus Disease 2019 Pandemic

OBJECTIVE

In the present study, we quantified the effect of the coronavirus disease 2019 (COVID-19) on the volume of adult and pediatric neurosurgical procedures, inpatient consultations, and clinic visits at an academic medical center.

METHODS

Neurosurgical procedures, inpatient consultations, and outpatient appointments at Vanderbilt University Medical Center were identified from March 23, 2020 through May 8, 2020 (during COVID-19) and March 25, 2019 through May 10, 2019 (before COVID-19). The neurosurgical volume was compared between the 2 periods.

RESULTS

A 40% reduction in weekly procedural volume was demonstrated during COVID-19 (median before, 75; interquartile range [IQR], 72-80; median during, 45; IQR, 43-47; P < 0.001). A 42% reduction occurred in weekly adult procedures (median before, 62; IQR, 54-70; median during, 36; IQR, 34-39; P < 0.001), and a 31% reduction occurred in weekly pediatric procedures (median before, 13; IQR, 12-14; median during, 9; IQR, 8-10; P = 0.004). Among adult procedures, the most significant decreases were seen for spine (P < 0.001) and endovascular (P < 0.001) procedures and cranioplasty (P < 0.001). A significant change was not found in the adult open vascular (P = 0.291), functional (P = 0.263), cranial tumor (P = 0.143), or hydrocephalus (P = 0.173) procedural volume. Weekly inpatient consultations to neurosurgery decreased by 24% (median before, 99; IQR, 94-114; median during, 75; IQR, 68-84; P = 0.008) for adults. Weekly in-person adult and pediatric outpatient clinic visits witnessed a 91% decrease (median before, 329; IQR, 326-374; median during, 29; IQR, 26-39; P < 0.001). In contrast, weekly telehealth encounters increased from a median of 0 (IQR, 0-0) before to a median of 151 (IQR, 126-156) during COVID-19 (P < 0.001).

CONCLUSIONS

Significant reductions occurred in neurosurgical operations, clinic visits, and inpatient consultations during COVID-19. Telehealth was increasingly used for assessments. The long-term effects of the reduced neurosurgical volume and increased telehealth usage on patient outcomes should be explored.

Seizure-onset regions demonstrate high inward directed connectivity during resting-state: An SEEG study in focal epilepsy

OBJECTIVE

In patients with medically refractory focal epilepsy, stereotactic-electroencephalography (SEEG) can aid in localizing epileptogenic regions for surgical treatment. SEEG, however, requires long hospitalizations to record seizures, and ictal interpretation can be incomplete or inaccurate. Our recent work showed that non-directed resting-state analyses may identify brain regions as epileptogenic or uninvolved. Our present objective is to map epileptogenic networks in greater detail and more accurately identify seizure-onset regions using directed resting-state SEEG connectivity.

METHODS

In 25 patients with focal epilepsy who underwent SEEG, 2 minutes of resting-state, artifact-free, SEEG data were selected and functional connectivity was estimated. Using standard clinical interpretation, brain regions were classified into four categories: ictogenic, early propagation, irritative, or uninvolved. Three non-directed connectivity measures (mutual information [MI] strength, and imaginary coherence between and within regions) and four directed measures (partial directed coherence [PDC] and directed transfer function [DTF], inward and outward strength) were calculated. Logistic regression was used to generate a predictive model of ictogenicity.

RESULTS

Ictogenic regions had the highest and uninvolved regions had the lowest MI strength. Although both PDC and DTF inward strengths were highest in ictogenic regions, outward strengths did not differ among categories. A model incorporating directed and nondirected connectivity measures demonstrated an area under the receiver-operating characteristic (ROC) curve (AUC) of 0.88 in predicting ictogenicity of individual regions. The AUC of this model was 0.93 when restricted to patients with favorable postsurgical seizure outcomes.

SIGNIFICANCE

Directed connectivity measures may help identify epileptogenic networks without requiring ictal recordings. Greater inward but not outward connectivity in ictogenic regions at rest may represent broad inhibitory input to prevent seizure generation.

Patient and parental assessment of factors influencing the choice of treatment in pediatric hydrocephalus

OBJECTIVE

Choosing between competing options (shunt or endoscopic third ventriculostomy) for the management of hydrocephalus requires patients and caregivers to make a subjective judgment about the relative importance of risks and benefits associated with each treatment. In the context of this particular decision, little is known about what treatment-related factors are important and how they are prioritized in order to arrive at a treatment preference.

METHODS

The Hydrocephalus Association electronically distributed a survey to surgically treated hydrocephalus patients or their families. Respondents rated the importance of various surgical attributes in their decision-making about treatment choice, and also indicated their preference in hypothetical scenarios involving a trade-off between potential risks and benefits of treatment. Rank-order correlations were used to determine whether certain predictor variables affected the rating of factors or hypothetical treatment choice.

RESULTS

Eighty percent of 414 respondents rated procedural risks, minimizing repeat surgery, and improving long-term brain function as being very or extremely important factors when deciding on a treatment; 69% rated the need to implant a permanent device similarly. Parent-respondents rated procedural risks higher than patient-respondents. A majority of respondents (n = 209, 54%) chose a procedure with higher surgical risk if it meant that implantation of a permanent device was not required, and respondents were more likely to choose this option if they discussed both treatment options with their surgeon prior to their initial intervention (Spearman rho 0.198, p = 0.001).Although only 144 of 384 total respondents (38%) chose a less established operation if it meant less repeat surgery, patient-respondents were more likely to choose this option compared to parent-respondents (Spearman rho 0.145, p = 0.005). Likewise, patient-respondents were more likely than parent-respondents to choose an operation that involved less repeat surgery and led to worse long-term brain function (Spearman rho 0.160, p = 0.002), an option that was chosen by only 23 (6%) of respondents overall.

CONCLUSIONS

This study is the first exploration of patient/parental factors that influence treatment preference in pediatric hydrocephalus. Procedural risks, minimizing repeat operations, and the desire to maximize long-term cognitive function appeared to be the most important attributes that influenced treatment decisions that the survey respondents had made in the past. Patients and/or their caregivers appear to see some inherent benefit in being shunt free. It appears that fear of multiple revision operations may drive treatment choice in some circumstances.

Surgical resource utilization after initial treatment of infant hydrocephalus: comparing ETV, early experience of ETV with choroid plexus cauterization, and shunt insertion in the Hydrocephalus Clinical Research Network

OBJECTIVE

Few studies have addressed surgical resource utilization-surgical revisions and associated hospital admission days-following shunt insertion or endoscopic third ventriculostomy (ETV) with or without choroid plexus cauterization (CPC) for CSF diversion in hydrocephalus. Study members of the Hydrocephalus Clinical Research Network (HCRN) investigated differences in surgical resource utilization between CSF diversion strategies in hydrocephalus in infants.

METHODS

Patients up to corrected age 24 months undergoing initial definitive treatment of hydrocephalus were reviewed from the prospectively maintained HCRN Core Data Project (Hydrocephalus Registry). Postoperative courses (at 1, 3, and 5 years) were studied for hydrocephalus-related surgeries (primary outcome) and hospital admission days related to surgical revision (secondary outcome). Data were summarized using descriptive statistics and compared using negative binomial regression, controlling for age, hydrocephalus etiology, and HCRN center. The study population was organized into 3 groups (ETV alone, ETV with CPC, and CSF shunt insertion) during the 1st postoperative year and 2 groups (ETV alone and CSF shunt insertion) during subsequent years due to limited long-term follow-up data.

RESULTS

Among 1090 patients, the majority underwent CSF shunt insertion (CSF shunt, 83.5%; ETV with CPC, 10.0%; and ETV alone, 6.5%). Patients undergoing ETV with CPC had a higher mean number of revision surgeries (1.2 ± 1.6) than those undergoing ETV alone (0.6 ± 0.8) or CSF shunt insertion (0.7 ± 1.3) over the 1st year after surgery (p = 0.005). At long-term follow-up, patients undergoing ETV alone experienced a nonsignificant lower mean number of revision surgeries (0.7 ± 0.9 at 3 years and 0.8 ± 1.3 at 5 years) than those undergoing CSF shunt insertion (1.1 ± 1.9 at 3 years and 1.4 ± 2.6 at 5 years) and exhibited a lower mean number of hospital admission days related to revision surgery (3.8 ± 10.3 vs 9.9 ± 27.0, p = 0.042).

CONCLUSIONS

Among initial treatment strategies for hydrocephalus, ETV with CPC yielded a higher surgical revision rate within 1 year after surgery. Patients undergoing ETV alone exhibited a nonsignificant lower mean number of surgical revisions than CSF shunt insertion at 3 and 5 years postoperatively. Additionally, the ETV-alone cohort demonstrated significantly fewer hospital admission days related to surgical management of hydrocephalus within 3 years after surgery. These findings suggest a time-dependent benefit of ETV over CSF shunt insertion regarding surgical resource utilization.

Mechatronic Design of a Two-Arm Concentric Tube Robot System for Rigid Neuroendoscopy

Open surgical approaches are still often employed in neurosurgery, despite the availability of neuroendoscopic approaches that reduce invasiveness. The challenge of maneuvering instruments at the tip of the endoscope makes neuroendoscopy demanding for the physician. The only way to aim tools passed through endoscope ports is to tilt the entire endoscope; but, tilting compresses brain tissue through which the endoscope passes and can damage it. Concentric tube robots can provide necessary dexterity without endoscope tilting, while passing through existing ports in the endoscope and carrying surgical tools in their inner lumen. In this paper we describe the mechatronic design of a new concentric tube robot that can deploy two concentric tube manipulators through a standard neuroendoscope. The robot uses a compact differential drive and features embedded motor control electronics and redundant position sensors for safety. In addition to the mechatronic design of this system, this paper contributes experimental validation in the context of colloid cyst removal, comparing our new robotic system to standard manual endoscopy in a brain phantom. The robotic approach essentially eliminated endoscope tilt during the procedure (17.09° for the manual approach vs. 1.16° for the robotic system). The robotic system also enables a single surgeon to perform the procedure - typically in a manual approach one surgeon aims the endoscope and another operates the tools delivered through its ports.

Association between supratentorial pediatric high-grade gliomas involved with the subventricular zone and decreased survival: a multi-institutional retrospective study

OBJECTIVE

The subventricular zone (SVZ), housed in the lateral walls of the lateral ventricles, is the largest neurogenic niche in the brain. In adults, high-grade gliomas in contact or involved with the SVZ are associated with decreased survival. Whether this association holds true in the pediatric population remains unexplored. To address this gap in knowledge, the authors conducted this retrospective study in a pediatric population with high-grade gliomas treated at three comprehensive centers in the United States.

METHODS

The authors retrospectively identified 63 patients, age ≤ 21 years, with supratentorial WHO grade III-IV gliomas treated at three academic centers. Basic demographic and clinical data regarding presenting signs and symptoms and common treatment variables were obtained. Preoperative MRI studies were evaluated to assess SVZ contact by tumor and to quantify tumor volume.

RESULTS

Sixty-three patients, including 34 males (54%), had a median age of 12.3 years (IQR 6.50-16.2) and a median tumor volume of 39.4 ml (IQR 19.4-65.8). Tumors contacting the SVZ (SVZ+) were noted in 34 patients (54%) and overall were larger than those not in contact with the SVZ (SVZ-; 51.1 vs 27.3, p = 0.002). The SVZ+ tumors were also associated with decreased survival. However, age, tumor volume, tumor grade, and treatment with chemotherapy and/or radiation were not associated with survival in the 63 patients. In the univariable analysis, near-total resection, gross-total resection, and seizure presentation were associated with increased survival (HR = 0.23, 95% CI 0.06-0.88, p = 0.03; HR = 0.26, 95% CI 0.09-0.74, p = 0.01; and HR = 0.46, 95% CI 0.22-0.97, p = 0.04, respectively). In a multivariable stepwise Cox regression analysis, only SVZ+ tumors remained significantly associated with decreased survival (HR = 1.94, 95% CI 1.03-3.64, p = 0.04).

CONCLUSIONS

High-grade glioma contact with the SVZ neural stem cell niche was associated with a significant decrease in survival in the pediatric population, as it is in the adult population. This result suggests that tumor contact with the SVZ is a general negative prognosticator in high-grade glioma independent of age group and invites biological investigations to understand the SVZ's role in glioma pathobiology.

Transcriptional analyses of adult and pediatric adamantinomatous craniopharyngioma reveals similar expression signatures regarding potential therapeutic targets

Adamantinomatous craniopharyngioma (ACP) is a biologically benign but clinically aggressive lesion that has a significant impact on quality of life. The incidence of the disease has a bimodal distribution, with peaks occurring in children and older adults. Our group previously published the results of a transcriptome analysis of pediatric ACPs that identified several genes that were consistently overexpressed relative to other pediatric brain tumors and normal tissue. We now present the results of a transcriptome analysis comparing pediatric to adult ACP to identify biological differences between these groups that may provide novel therapeutic insights or support the assertion that potential therapies identified through the study of pediatric ACP may also have a role in adult ACP. Using our compiled transcriptome dataset of 27 pediatric and 9 adult ACPs, obtained through the Advancing Treatment for Pediatric Craniopharyngioma Consortium, we interrogated potential age-related transcriptional differences using several rigorous mathematical analyses. These included: canonical differential expression analysis; divisive, agglomerative, and probabilistic based hierarchical clustering; information theory based characterizations; and the deep learning approach, HD Spot. Our work indicates that there is no therapeutically relevant difference in ACP gene expression based on age. As such, potential therapeutic targets identified in pediatric ACP are also likely to have relvance for adult patients.

Cerebrospinal fluid alterations following endoscopic third ventriculostomy with choroid plexus cauterization: a retrospective laboratory analysis of two tertiary care centers

PURPOSE

This study sought to determine the previously undescribed cytologic and metabolic alterations that accompany endoscopic third ventriculostomy with choroid plexus cauterization (ETV/CPC).

METHODS

Cerebrospinal fluid (CSF) samples were collected from infant patients with hydrocephalus at the time of index ETV/CPC and again at each reintervention for persistent hydrocephalus. Basic CSF parameters, including glucose, protein, and cell counts, were documented. A multivariable regression model, incorporating known predictors of ETV/CPC outcome, was constructed for each parameter to inform time-dependent normative values.

RESULTS

A total of 187 infants were treated via ETV/CPC for hydrocephalus; initial laboratory values were available for 164 patients. Etiology of hydrocephalus included myelomeningocele (53, 32%), intraventricular hemorrhage of prematurity (43, 26%), aqueductal stenosis (24, 15%), and others (44, 27%). CSF parameters did not differ significantly with age or etiology. Glucose levels initially drop below population average (36 to 32 mg/dL) post-operatively before slowly rising to normal levels (42 mg/dL) by 3 months. Dramatically elevated protein levels post-ETV/CPC (baseline of 59 mg/dL up to roughly 200 mg/dL at 1 month) also normalized over 3 months. No significant changes were appreciated in WBC. RBC counts were very elevated following ETV/CPC and quickly declined over the subsequent month.

CONCLUSION

CSF glucose and protein deviate significantly from normal ranges following ETV/CPC before normalizing over 3 months. High RBC values immediately post-ETV/CPC decline rapidly. Age at time of procedure and etiology have little influence on common clinical CSF laboratory parameters. Of note, the retrospective study design necessitates ETV/CPC failure, which could introduce bias in the results.

Timing of syrinx reduction and stabilization after posterior fossa decompression for pediatric Chiari malformation type I

OBJECTIVE

The aim of this study was to determine the timeline of syrinx regression and to identify factors mitigating syrinx resolution in pediatric patients with Chiari malformation type I (CM-I) undergoing posterior fossa decompression (PFD).

METHODS

The authors conducted a retrospective review of records from pediatric patients (< 18 years old) undergoing PFD for the treatment of CM-I/syringomyelia (SM) between 1998 and 2015. Patient demographic, clinical, radiological, and surgical variables were collected and analyzed. Radiological information was reviewed at 4 time points: 1) pre-PFD, 2) within 6 months post-PFD, 3) within 12 months post-PFD, and 4) at maximum available follow-up. Syrinx regression was defined as ≥ 50% decrease in the maximal anteroposterior syrinx diameter (MSD). The time to syrinx regression was determined using Kaplan-Meier analysis. Multivariate analysis was conducted using a Cox proportional hazards model to determine the association between preoperative, clinical, and surgery-related factors and syrinx regression.

RESULTS

The authors identified 85 patients with CM-I/SM who underwent PFD. Within 3 months post-PFD, the mean MSD regressed from 8.1 ± 3.4 mm (preoperatively) to 5.6 ± 2.9 mm within 3 months post-PFD. Seventy patients (82.4%) achieved ≥ 50% regression in MSD. The median time to ≥ 50% regression in MSD was 8 months (95% CI 4.2-11.8 months). Using a risk-adjusted multivariable Cox proportional hazards model, the patients who underwent tonsil coagulation (n = 20) had a higher likelihood of achieving ≥ 50% syrinx regression in a shorter time (HR 2.86, 95% CI 1.2-6.9; p = 0.02). Thirty-six (75%) of 45 patients had improvement in headache at 2.9 months (IQR 1.5-4.4 months).

CONCLUSIONS

The maximum reduction in syrinx size can be expected within 3 months after PFD for patients with CM-I and a syrinx; however, the syringes continue to regress over time. Tonsil coagulation was associated with early syrinx regression in this cohort. However, the role of surgical maneuvers such as tonsil coagulation and arachnoid veil identification and sectioning in the overall role of CM-I surgery remains unclear.

The Preventable Shunt Revision Rate: A Multicenter Evaluation

BACKGROUND

The Preventable Shunt Revision Rate (PSRR) was recently introduced as a novel quality metric.

OBJECTIVE

To evaluate the PSRR across multiple centers and determine associated variables.

METHODS

Nine participating centers in North America provided at least 2 years of consecutive shunt operations. Index surgery was defined as new shunt implantation, or revision of an existing shunt. For any index surgery that resulted in a reoperation within 90-days, index surgery information (demographic, clinical, and procedural) was collected and a decision made whether the failure was potentially preventable. The 90-day shunt failure rate and PSRR were calculated per institution and combined. Bivariate analyses were performed to evaluate individual effects of each independent variable on preventable shunt failure followed by a final multivariable model using a backward model selection approach.

RESULTS

A total of 5092 shunt operations were performed; 861 failed within 90 days of index operation, resulting in a 16.9% combined 90-day shunt failure rate and 17.6% median failure rate (range, 8.7%-26.9%). Of the failures, 307 were potentially preventable (overall and median 90-day PSRR, 35.7% and 33.9%, respectively; range, 16.1%-55.4%). The most common etiologies of avoidable failure were infection (n = 134, 44%) and proximal catheter malposition (n = 83, 27%). Independent predictors of preventable failure (P < .05) were lack of endoscopy (odds ratio [OR] = 2.26), recent shunt infection (OR = 3.65), shunt type (OR = 2.06) and center.

CONCLUSION

PSRR is variable across institutions, but can be 50% or higher. While the PSRR may never reach zero, this study demonstrates that overall about a third of early failures are potentially preventable.

Graft dural closure is associated with a reduction in CSF leak and hydrocephalus in pediatric patients undergoing posterior fossa brain tumor resection

OBJECTIVE

The authors aimed to evaluate clinical, radiological, and surgical factors associated with posterior fossa tumor resection (PFTR)-related outcomes, including postoperative complications related to dural augmentation (CSF leak and wound infection), persistent hydrocephalus ultimately requiring permanent CSF diversion after PFTR, and 90-day readmission rate.

METHODS

Pediatric patients (0-17 years old) undergoing PFTR between 2000 and 2016 at Monroe Carell Jr. Children's Hospital of Vanderbilt University were retrospectively reviewed. Descriptive statistics included the Wilcoxon signed-rank test to compare means that were nonnormally distributed and the chi-square test for categorical variables. Variables that were nominally associated (p < 0.05) with each outcome by univariate analysis were included as covariates in multivariate linear regression models. Statistical significance was set a priori at p < 0.05.

RESULTS

The cohort consisted of 186 patients with a median age at surgery of 6.62 years (range 3.37-11.78 years), 55% male, 83% Caucasian, and average length of follow-up of 3.87 ± 0.25 years. By multivariate logistic regression, the variables primary dural closure (PDC; odds ratio [OR] 8.33, 95% confidence interval [CI] 1.07-100, p = 0.04), pseudomeningocele (OR 7.43, 95% CI 2.23-23.76, p = 0.0007), and hydrocephalus ultimately requiring permanent CSF diversion within 90 days of PFTR (OR 9.25, 95% CI 2.74-31.2, p = 0.0003) were independently associated with CSF leak. PDC versus graft dural closure (GDC; 35% vs 7%, OR 5.88, 95% CI 2.94-50.0, p = 0.03) and hydrocephalus ultimately requiring permanent CSF diversion (OR 3.30, 95% CI 1.07-10.19, p = 0.0007) were associated with wound infection requiring surgical debridement. By multivariate logistic regression, GDC versus PDC (23% vs 37%, OR 0.13, 95% CI 0.02-0.87, p = 0.04) was associated with persistent hydrocephalus ultimately requiring permanent CSF diversion, whereas pre- or post-PFTR ventricular size, placement of peri- or intraoperative extraventricular drain (EVD), and radiation therapy were not. Furthermore, the addition of perioperative EVD placement and dural closure method to a previously validated predictive model of post-PFTR hydrocephalus improved its performance from area under the receiver operating characteristic curve of 0.69 to 0.74. Lastly, the authors found that autologous (vs synthetic) grafts may be protective against persistent hydrocephalus (p = 0.02), but not CSF leak, pseudomeningocele, or wound infection.

CONCLUSIONS

These results suggest that GDC, independent of potential confounding factors, may be protective against CSF leak, wound infection, and hydrocephalus in patients undergoing PFTR. Additional studies are warranted to further evaluate clinical and surgical factors impacting PFTR-associated complications.

Stereotactic EEG via multiple single-path omnidirectional trajectories within a single platform: institutional experience with a novel technique

OBJECTIVEStereotactic electroencephalography (SEEG) is being used with increasing frequency to interrogate subcortical, cortical, and multifocal epileptic foci. The authors describe a novel technique for SEEG in patients with suspected epileptic foci refractory to medical management.METHODSIn the authors' technique, standard epilepsy evaluation and neuroimaging are used to create a hypothesis-driven SEEG plan, which informs the 3D printing of a novel single-path, multiple-trajectory, omnidirectional platform. Following skull-anchor platform fixation, electrodes are sequentially inserted according to the preoperative plan. The authors describe their surgical experience and technique based on a review of all cases, adult and pediatric, in which patients underwent invasive epilepsy monitoring via SEEG during an 18-month period at Vanderbilt University Medical Center. Platform and anatomical variables influencing localization error were evaluated using multivariate linear regression.RESULTSUsing this novel technology, 137 electrodes were inserted in 15 patients with focal epilepsy with favorable recording results and no clinical complications. The mean entry point localization error was 1.42 mm (SD 0.98 mm), and the mean target point localization error was 3.36 mm (SD 2.68 mm). Platform distance, electrode trajectory angle, and intracranial distance, but not skull thickness, were independently associated with localization error.CONCLUSIONSThe multiple-trajectory, single-path, omnidirectional platform offers satisfactory accuracy and favorable clinical results, while avoiding cumbersome frames and prohibitive up-front costs associated with other SEEG technologies.

Predictors of success for combined endoscopic third ventriculostomy and choroid plexus cauterization in a North American setting: a Hydrocephalus Clinical Research Network study

OBJECTIVE

Endoscopic third ventriculostomy combined with choroid plexus cauterization (ETV+CPC) has been adopted by many pediatric neurosurgeons as an alternative to placing shunts in infants with hydrocephalus. However, reported success rates have been highly variable, which may be secondary to patient selection, operative technique, and/or surgeon training. The objective of this prospective multicenter cohort study was to identify independent patient selection, operative technique, or surgical training predictors of ETV+CPC success in infants.

METHODS

This was a prospective cohort study nested within the Hydrocephalus Clinical Research Network's (HCRN) Core Data Project (registry). All infants under the age of 2 years who underwent a first ETV+CPC between June 2006 and March 2015 from 8 HCRN centers were included. Each patient had a minimum of 6 months of follow-up unless censored by an ETV+CPC failure. Patient and operative risk factors of failure were examined, as well as formal ETV+CPC training, which was defined as traveling to and working with the experienced surgeons at CURE Children's Hospital of Uganda. ETV+CPC failure was defined as the need for repeat ETV, shunting, or death.

RESULTS

The study contained 191 patients with a primary ETV+CPC conducted by 17 pediatric neurosurgeons within the HCRN. Infants under 6 months corrected age at the time of ETV+CPC represented 79% of the cohort. Myelomeningocele (26%), intraventricular hemorrhage associated with prematurity (24%), and aqueductal stenosis (17%) were the most common etiologies. A total of 115 (60%) of the ETV+CPCs were conducted by surgeons after formal training. Overall, ETV+CPC was successful in 48%, 46%, and 45% of infants at 6 months, 1 year, and 18 months, respectively. Young age (< 1 month) (adjusted hazard ratio [aHR] 1.9, 95% CI 1.0-3.6) and an etiology of post-intraventricular hemorrhage secondary to prematurity (aHR 2.0, 95% CI 1.1-3.6) were the only two independent predictors of ETV+CPC failure. Specific subgroups of ages within etiology categories were identified as having higher ETV+CPC success rates. Although training led to more frequent use of the flexible scope (p < 0.001) and higher rates of complete (> 90%) CPC (p < 0.001), training itself was not independently associated (aHR 1.1, 95% CI 0.7-1.8; p = 0.63) with ETV+CPC success.

CONCLUSIONS

This is the largest prospective multicenter North American study to date examining ETV+CPC. Formal ETV+CPC training was not found to be associated with improved procedure outcomes. Specific subgroups of ages within specific hydrocephalus etiologies were identified that may preferentially benefit from ETV+CPC.

Predictors of endoscopic third ventriculostomy ostomy status in patients who experience failure of endoscopic third ventriculostomy with choroid plexus cauterization

OBJECTIVE

At failure of endoscopic third ventriculostomy (ETV) with choroid plexus cauterization (CPC), the ETV ostomy may be found to be closed or open. Failure with a closed ostomy may indicate a population that could benefit from evolving techniques to keep the ostomy open and may be candidates for repeat ETV, whereas failure with an open ostomy may be due to persistently abnormal CSF dynamics. This study seeks to identify clinical and radiographic predictors of ostomy status at the time of ETV/CPC failure.

METHODS

The authors conducted a multicenter, retrospective cohort study on all pediatric patients with hydrocephalus who failed initial ETV/CPC treatment between January 2013 and October 2016. Failure was defined as the need for repeat ETV or ventriculoperitoneal (VP) shunt placement. Clinical and radiographic data were collected, and ETV ostomy status was determined endoscopically at the subsequent hydrocephalus procedure. Statistical analysis included the Mann-Whitney U-test, Wilcoxon rank-sum test, t-test, and Pearson chi-square test where appropriate, as well as multivariate logistic regression.

RESULTS

Of 72 ETV/CPC failures, 28 patients (39%) had open-ostomy failure and 44 (61%) had closed-ostomy failure. Patients with open-ostomy failure were older (median 5.1 weeks corrected age for gestation [interquartile range (IQR) 0.9-15.9 weeks]) than patients with closed-ostomy failure (median 0.2 weeks [IQR -1.3 to 4.5 weeks]), a significant difference by univariate and multivariate regression. Etiologies of hydrocephalus included intraventricular hemorrhage of prematurity (32%), myelomeningocele (29%), congenital communicating (11%), aqueductal stenosis (11%), cyst/tumor (4%), and other causes (12%). A wider baseline third ventricle was associated with open-ostomy failure (median 15.0 mm [IQR 10.3-18.5 mm]) compared to closed-ostomy failure (median 11.7 mm [IQR 8.9-16.5 mm], p = 0.048). Finally, at the time of failure, patients with closed-ostomy failure had enlargement of their ventricles (frontal and occipital horn ratio [FOHR], failure vs baseline, median 0.06 [IQR 0.00-0.11]), while patients with open-ostomy failure had no change in ventricle size (median 0.01 [IQR -0.04 to 0.05], p = 0.018). Previous CSF temporizing procedures, intraoperative bleeding, and time to failure were not associated with ostomy status at ETV/CPC failure.

CONCLUSIONS

Older corrected age for gestation, larger baseline third ventricle width, and no change in FOHR were associated with open-ostomy ETV/CPC failure. Future studies are warranted to further define and confirm features that may be predictive of ostomy status at the time of ETV/CPC failure.

Incidence of Epilepsy and Associated Risk Factors in Perinatal Ischemic Stroke Survivors

INTRODUCTION

Epilepsy is a serious and often lifelong consequence of perinatal arterial ischemic stroke (PAIS). Variable incidences and risk factors for long-term epilepsy in PAIS have been reported. To determine the incidence of epilepsy in PAIS survivors and report factors associated with the risk of developing epilepsy, a meta-analysis and systematic review of prior publications was performed.

METHODS

We examined studies on perinatal or neonatal patients (≤28 days of life) with arterial ischemic strokes in which the development of epilepsy was reported. EMBASE and MEDLINE/PubMed databases were systematically searched in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses.

RESULTS

A meta-analysis of 10 studies revealed a summary incidence of epilepsy in PAIS patients of 27.2% (95% confidence interval 16.6% to 41.4%) over a mean study duration of 10.4 years (range 1.5 to 17). More recent studies generally reported a lower epilepsy incidence. A systematic review identified seven possible risk factors for epilepsy in PAIS patients: hippocampal volume reduction, infarct on prenatal ultrasound, a modified Alberta Stroke Program Early Computed Tomography score ≥9, family history of seizures, cerebral palsy, and initial presentation with cognitive impairment or seizures.

CONCLUSIONS

About a third of children with PAIS will develop epilepsy. While seven possible risk factors have been reported, further research is warranted to confirm the strength of their association with the development of epilepsy.

North American survey on the post-neuroimaging management of children with mild head injuries

OBJECTIVEThere remains uncertainty regarding the appropriate level of care and need for repeating neuroimaging among children with mild traumatic brain injury (mTBI) complicated by intracranial injury (ICI). This study's objective was to investigate physician practice patterns and decision-making processes for these patients in order to identify knowledge gaps and highlight avenues for future investigation.METHODSThe authors surveyed residents, fellows, and attending physicians from the following pediatric specialties: emergency medicine; general surgery; neurosurgery; and critical care. Participants came from 10 institutions in the United States and an email list maintained by the Canadian Neurosurgical Society. The survey asked respondents to indicate management preferences for and experiences with children with mTBI complicated by ICI, focusing on an exemplar clinical vignette of a 7-year-old girl with a Glasgow Coma Scale score of 15 and a 5-mm subdural hematoma without midline shift after a fall down stairs.RESULTSThe response rate was 52% (n = 536). Overall, 326 (61%) respondents indicated they would recommend ICU admission for the child in the vignette. However, only 62 (12%) agreed/strongly agreed that this child was at high risk of neurological decline. Half of respondents (45%; n = 243) indicated they would order a planned follow-up CT (29%; n = 155) or MRI scan (19%; n = 102), though only 64 (12%) agreed/strongly agreed that repeat neuroimaging would influence their management. Common factors that increased the likelihood of ICU admission included presence of a focal neurological deficit (95%; n = 508 endorsed), midline shift (90%; n = 480) or an epidural hematoma (88%; n = 471). However, 42% (n = 225) indicated they would admit all children with mTBI and ICI to the ICU. Notably, 27% (n = 143) of respondents indicated they had seen one or more children with mTBI and intracranial hemorrhage demonstrate a rapid neurological decline when admitted to a general ward in the last year, and 13% (n = 71) had witnessed this outcome at least twice in the past year.CONCLUSIONSMany physicians endorse ICU admission and repeat neuroimaging for pediatric mTBI with ICI, despite uncertainty regarding the clinical utility of those decisions. These results, combined with evidence that existing practice may provide insufficient monitoring to some high-risk children, emphasize the need for validated decision tools to aid the management of these patients.

The cost of hydrocephalus: a cost-effectiveness model for evaluating surgical techniques

In BriefThe authors analyzed the costs associated with the three different procedures used to treat hydrocephalus in the pediatric population. They believe this study highlights the importance of patient-specific treatment decisions that are based on etiology and previous intervention. The patient-specific medical characteristics are a driving force in the cost of care.

Oral presentation to publication: publication rates of abstract presentations across two pediatric neurosurgical meetings

OBJECTIVE Both the American Association of Neurological Surgeons/Congress of Neurological Surgeons Joint Section on Pediatric Neurological Surgery (AANS/CNS Pediatric Section) and the International Society for Pediatric Neurosurgery (ISPN) annual meetings provide a platform for pediatric neurosurgeons to present, discuss, and disseminate current academic research. An ultimate goal of these meetings is to publish presented results in peer-reviewed journals. The purpose of the present study was to investigate the publication rates of oral presentations from the 2009, 2010, and 2011 AANS/CNS Pediatric Section and ISPN annual meetings in peer-reviewed journals. METHODS All oral presentations from the 2009, 2010, and 2011 AANS/CNS Pediatric Section and ISPN annual meetings were reviewed. Abstracts were obtained from the AANS/CNS Pediatric Section and ISPN conference proceedings, which are available online. Author and title information were used to search PubMed to identify those abstracts that had progressed to publication in peer-reviewed journals. The title of the journal, year of the publication, and authors' country of origin were also recorded. RESULTS Overall, 60.6% of the presented oral abstracts from the AANS/CNS Pediatric Section meetings progressed to publication in peer-reviewed journals, as compared with 40.6% of the ISPN presented abstracts (p = 0.0001). The journals in which the AANS/CNS Pediatric Section abstract-based publications most commonly appeared were Journal of Neurosurgery: Pediatrics (52%), Child's Nervous System (11%), and Journal of Neurosurgery (8%). The ISPN abstracts most often appeared in the journals Child's Nervous System (29%), Journal of Neurosurgery: Pediatrics (14%), and Neurosurgery (9%). Overall, more than 90% of the abstract-based articles were published within 4 years after presentation of the abstracts on which they were based. CONCLUSIONS Oral abstract presentations at two annual pediatric neurosurgery meetings have publication rates in peer-reviewed journal comparable to those for oral abstracts at other national and international neurosurgery meetings. The vast majority of abstract-based papers are published within 4 years of the meeting at which the abstract was presented; however, the AANS/CNS Pediatric Section abstracts are published at a significantly higher rate than ISPN abstracts, which could indicate the different meeting sizes, research goals, and resources of US authors compared with those of authors from other countries.

Comparison of hydrocephalus metrics between infants successfully treated with endoscopic third ventriculostomy with choroid plexus cauterization and those treated with a ventriculoperitoneal shunt: a multicenter matched-cohort analysis

OBJECTIVE It has been suggested that the treatment of infant hydrocephalus results in different craniometric changes depending upon whether ventriculoperitoneal shunt (VPS) placement or endoscopic third ventriculostomy with choroid plexus cauterization (ETV/CPC) is performed. Without an objective and quantitative description of expected changes to the infant cranium and ventricles following ETV/CPC, asserting successful treatment of hydrocephalus is difficult. By comparing infants successfully treated via ETV/CPC or VPS surgery, the authors of this study aimed to define the expected postoperative cranial and ventricular alterations at the time of clinical follow-up. METHODS Patients who underwent successful treatment of hydrocephalus at 4 institutions with either VPS placement or ETV/CPC were matched in a 3:1 ratio on the basis of age and etiology. Commonly used cranial parameters (including head circumference [HC], HC z-score, fontanelle status, and frontooccipital horn ratio [FOHR]) were compared pre- and postoperatively between treatment cohorts. First, baseline preoperative values were compared to ensure cohort equivalence. Next, postoperative metrics, including the relative change in metrics, were compared between treatment groups using multivariate linear regression. RESULTS Across 4 institutions, 18 ETV/CPC-treated and 54 VPS-treated infants with hydrocephalus were matched and compared at 6 months postoperatively. The most common etiologies of hydrocephalus were myelomeningocele (61%), followed by congenital communicating hydrocephalus (17%), aqueductal stenosis (11%), and intraventricular hemorrhage (6%). The mean age at the time of CSF diversion was similar between ETV/CPC- and VPS-treated patients (3.4 vs 2.9 months; p = 0.69), as were all preoperative cranial hydrocephalus metrics (p > 0.05). Postoperatively, the ventricle size FOHR decreased significantly more following VPS surgery (-0.15) than following ETV/CPC (-0.02) (p < 0.001), yielding a lower postoperative FOHR in the VPS arm (0.42 vs 0.51; p = 0.01). The HC percentile was greater in the ETV/CPC cohort than in the VPS-treated patients (76th vs 54th percentile; p = 0.046). A significant difference in the postoperative z-score was not observed. With both treatment modalities, a bulging fontanelle reliably normalized at last follow-up. CONCLUSIONS Clinical and radiographic parameters following successful treatment of hydrocephalus in infants differed between ETV/CPC and VPS treatment. At 6 months post-ETV/CPC, ventricle size remained unchanged, whereas VPS-treated ventricles decreased to a near-normal FOHR. The HC growth control between the procedures was similar, although the final HC percentile may be lower after VPS. The fontanelle remained a reliable indicator of success for both treatments. This study establishes expected cranial and ventricular parameters following ETV/CPC, which may be used to guide preoperative counseling and postoperative decision making.

Management of Penetrating Cerebrovascular Injuries in Pediatric Trauma: A Retrospective Multicenter Study

BACKGROUND

Blunt cerebrovascular injury is uncommon in the pediatric population; penetrating cerebrovascular injuries are even rarer and are thus poorly understood.

OBJECTIVE

To describe the diagnosis and management of penetrating cerebrovascular injuries and describe outcomes of available treatment modalities.

METHODS

Clinical and radiographic data were collected retrospectively from a multicenter trauma registry for children screened for cerebrovascular injury during 2003 to 2013 at 4 academic pediatric trauma centers.

RESULTS

Among 645 pediatric patients evaluated with computed tomography angiography with blunt cerebrovascular injury, 130 also had a penetrating trauma indication. Seven penetrating cerebrovascular injuries were diagnosed in 7 male patients (mean age 12.4 years, range 12-18 years). Focal neurological deficit and concomitant intracranial injury were each seen in 2 patients. There were 2 intracranial carotid artery injuries, 4 extracranial carotid artery injuries, and 1 vertebral artery injury. The majority of injuries were higher than grade I (5/7; 71%): 2 were grade I, 1 grade II, 2 grade III, and 2 grade IV. The 2 patients with grade III injuries required open surgery, and 1 patient with a grade IV injury underwent endovascular treatment. Two patients suffered immediate stroke secondary to the penetrating cerebrovascular injury. There were no delayed neurological deficits from the penetrating injuries, and no patients died as a result of the injuries.

CONCLUSION

This is the largest series of penetrating cerebrovascular trauma in the pediatric literature. Although rare, penetrating cerebrovascular injuries can be high-grade injuries that require urgent recognition and may require aggressive endovascular and/or open surgery for treatment.

Endoscopic third ventriculostomy and choroid plexus cauterization in infant hydrocephalus: a prospective study by the Hydrocephalus Clinical Research Network

OBJECTIVE High-quality data comparing endoscopic third ventriculostomy (ETV) with choroid plexus cauterization (CPC) to shunt and ETV alone in North America are greatly lacking. To address this, the Hydrocephalus Clinical Research Network (HCRN) conducted a prospective study of ETV+CPC in infants. Here, these prospective data are presented and compared to prospectively collected data from a historical cohort of infants treated with shunt or ETV alone. METHODS From June 2014 to September 2015, infants (corrected age ≤ 24 months) requiring treatment for hydrocephalus with anatomy suitable for ETV+CPC were entered into a prospective study at 9 HCRN centers. The rate of procedural failure (i.e., the need for repeat hydrocephalus surgery, hydrocephalus-related death, or major postoperative neurological deficit) was determined. These data were compared with a cohort of similar infants who were treated with either a shunt (n = 969) or ETV alone (n = 74) by creating matched pairs on the basis of age and etiology. These data were obtained from the existing prospective HCRN Core Data Project. All patients were observed for at least 6 months. RESULTS A total of 118 infants underwent ETV+CPC (median corrected age 1.3 months; common etiologies including myelomeningocele [30.5%], intraventricular hemorrhage of prematurity [22.9%], and aqueductal stenosis [21.2%]). The 6-month success rate was 36%. The most common complications included seizures (5.1%) and CSF leak (3.4%). Important predictors of treatment success in the survival regression model included older age (p = 0.002), smaller preoperative ventricle size (p = 0.009), and greater degree of CPC (p = 0.02). The matching algorithm resulted in 112 matched pairs for ETV+CPC versus shunt alone and 34 matched pairs for ETV+CPC versus ETV alone. ETV+CPC was found to have significantly higher failure rate than shunt placement (p < 0.001). Although ETV+CPC had a similar failure rate compared with ETV alone (p = 0.73), the matched pairs included mostly infants with aqueductal stenosis and miscellaneous other etiologies but very few patients with intraventricular hemorrhage of prematurity. CONCLUSIONS Within a large and broad cohort of North American infants, our data show that overall ETV+CPC appears to have a higher failure rate than shunt alone. Although the ETV+CPC results were similar to ETV alone, this comparison was limited by the small sample size and skewed etiological distribution. Within the ETV+CPC group, greater extent of CPC was associated with treatment success, thereby suggesting that there are subgroups who might benefit from the addition of CPC. Further work will focus on identifying these subgroups.

Unplanned readmission within 90 days after pediatric neurosurgery

OBJECTIVE Readmission and return to operating room after surgery are increasingly being used as a proxy for quality of care. Nearly 60% of these readmissions are unplanned, which translates into billions of dollars in health care costs. The authors set out to analyze the incidence of readmission at their center, to define causes of unplanned readmission, and to determine the preoperative and surgical variables associated with readmissions following pediatric neurosurgery. METHODS A total of 536 children who underwent operations for neurosurgical diagnoses between 2012 and 2015 and who were later readmitted were included in the final analysis. Unplanned readmissions were defined to have occurred as a result of complications within 90 days after index surgery. Patient records were retrospectively reviewed to determine the primary diagnosis, surgery indication, and cause of readmission and return to operating room. The cost for index hospitalization, readmission episode, and total cost were derived based on the charges obtained from administrative data. Bivariate and multivariable analyses were conducted. RESULTS Of 536 patients readmitted in total, 17.9% (n = 96) were readmitted within 90 days. Of the overall readmissions, 11.9% (n = 64) were readmitted within 30 days, and 5.97% (n = 32) were readmitted between 31 and 90 days. The median duration between discharge and readmission was 20 days (first quartile [Q1]: 9 days, third quartile [Q3]: 36 days). The most common reason for readmission was shunt related (8.2%, n = 44), followed by wound infection (4.7%, n = 25). In the risk-adjusted multivariable logistic regression model for total 90-day readmission, patients with the following characteristics: younger age (p = 0.001, OR 0.886, 95% CI 0.824-0.952); "other" (nonwhite, nonblack) race (p = 0.024, OR 5.49, 95% CI 1.246-24.2); and those born preterm (p = 0.032, OR 2.1, 95% CI 1.1-4.12) had higher odds of being readmitted within 90 days after discharge. The total median cost for patients undergoing surgery in this study cohort was $11,520 (Q1: $7103, Q3: $19,264). For the patients who were readmitted, the median cost for a readmission episode was $8981 (Q1: $5051, Q3: $18,713). CONCLUSIONS Unplanned 90-day readmissions in pediatric neurosurgery are primarily due to CSF-related complications. Patients with the following characteristics: young age at presentation; "other" race; and children born preterm have a higher likelihood of being readmitted within 90 days after surgery. The median cost was > $8000, which suggests that the readmission episode can be as expensive as the index hospitalization. Clearly, readmission reduction has the potential for significant cost savings in pediatric neurosurgery. Future efforts, such as targeted education related to complication signs, should be considered in the attempt to reduce unplanned events. Given the single-center, retrospective study design, the results of this study are primarily applicable to this population and cannot necessarily be generalized to other institutions without further study.

Treatment Practices and Outcomes After Blunt Cerebrovascular Injury in Children

BACKGROUND

Pediatric blunt cerebrovascular injury (BCVI) lacks accepted treatment algorithms, and postinjury outcomes are ill defined.

OBJECTIVE

To compare treatment practices among pediatric trauma centers and to describe outcomes for available treatment modalities.

METHODS

Clinical and radiographic data were collected from a patient cohort with BCVI between 2003 and 2013 at 4 academic pediatric trauma centers.

RESULTS

Among 645 pediatric patients evaluated with computed tomography angiography for BCVI, 57 vascular injuries (82% carotid artery, 18% vertebral artery) were diagnosed in 52 patients. Grade I (58%) and II (23%) injuries accounted for most lesions. Severe intracranial or intra-abdominal hemorrhage precluded antithrombotic therapy in 10 patients. Among the remaining patients, primary therapy was an antiplatelet agent in 14 (33%), anticoagulation in 8 (19%), endovascular intervention in 3 (7%), open surgery in 1 (2%), and no treatment in 16 (38%). Among 27 eligible grade I injuries, 16 (59%) were not treated, and the choice to not treat varied significantly among centers (P < .001). There were no complications from medical management. Glasgow Coma Scale (GCS) score <8 and increasing injury grade were predictors of injury progression (P = .001 and .004, respectively). Poor GCS score (P = .02), increasing injury grade (P = .03), and concomitant intracranial injury (P = .02) correlated with increased risk of mortality. Treatment modality did not correlate with progression of vascular injury or mortality.

CONCLUSION

Treatment of BCVI with antiplatelet or anticoagulant therapy is safe and may confer modest benefit. Nonmodifiable factors, including presenting GCS score, vascular injury grade, and additional intracranial injury, remain the most important predictors of poor outcome.

ABBREVIATIONS

ATT, antithrombotic therapyBCVI, blunt cerebrovascular injuryCTA, computed tomography angiographyGCS, Glasgow Coma Scale.

X-ray vs. CT in identifying significant C-spine injuries in the pediatric population

PURPOSE

Evaluation of cervical spine injury (CSI) in children requires rapid, yet accurate assessment of damage. Given concerns of radiation exposure, expert consensus advises that computed tomography (CT) should be used sparingly. However, CT can provide superior image resolution and detection of pathology. Herein, we evaluate if X-ray offers equal diagnostic accuracy compared to CT imaging in identifying CSI in children.

METHODS

We conducted a retrospective study between October 2000 and March 2012 of pediatric patients evaluated for cervical spine injury at a level 1 trauma center. All patients included in this study were imaged with cervical spine X-rays and CT at the time of injury. Demographic information, mechanism of injury, significant versus non-significant injury (as defined by the NEXUS criteria), radiographic findings, level of the injury, presence of spinal cord injury, treatment, clinical outcome, and length of follow-up were collected. Chi-squared (χ ²) and Fisher's exact tests were used as appropriate and means and standard deviations were reported.

RESULTS

We identified 1296 patients who were screened for CSI. Of those, 164 patients were diagnosed with spinal cord/column injuries (CSI). Eighty-nine patients were excluded for only having a CT or X-ray imaging without the other modality. Thus, a total of 75 patients with CSI were included in the final cohort. Using the NEXUS definitions, 78% of patients had clinically significant injuries while 22% had non-significant injuries. There were no injuries detected on X-ray that were not also detected on CT. For all injuries, X-ray sensitivity was 50.7%. X-rays were more sensitive to significant injuries (62.3%) compared in non-significant injuries, which were missed on all X-rays (0%). Therefore, X-rays did not identify 24 significant cervical spine injuries (32%) as defined by NEXUS.

CONCLUSIONS

CT is superior to X-rays in detecting both clinically significant and insignificant cervical spine injuries. These results were not dependent on patient age or location of the injury. We recommend CT imaging in the evaluation of suspected cervical spine injuries in children.

LEVEL OF EVIDENCE

III.