The role of systemic hemodynamic disturbances in prematurity-related brain injury

Shaking Up Our Approach: The Need for Characterization and Optimization of Pre-clinical Models of Infant Abusive Head Trauma

Traumatic brain injuries (TBIs) are a large societal and individual burden. In the first year of life, the vast majority of these injuries are the result of inflicted abusive events by a trusted caregiver. Abusive head trauma (AHT) in infants, formerly known as shaken baby syndrome, is the leading cause of inflicted mortality and morbidity in this population. In this review we address clinical diagnosis, symptoms, prognosis, and neuropathology of AHT, emphasizing the burden of repetitive AHT. Next, we consider existing animal models of AHT, and we evaluate key features of an ideal model, highlighting important developmental milestones in children most vulnerable to AHT. We draw on insights from other injury models, such as repetitive, mild TBIs (RmTBIs), post-traumatic epilepsy (PTE), hypoxic-ischemic injuries, and maternal neglect, to speculate on key knowledge gaps and underline important new opportunities in pre-clinical AHT research. Finally, potential treatment options to facilitate healthy development in children following an AHT are considered. Together, this review aims to drive the field toward optimized, well-characterized animal models of AHT, which will allow for greater insight into the underlying neuropathological and neurobehavioral consequences of AHT.

Hydrocephalus in prematurity: does valve choice make a difference?

PURPOSE

Extremely premature neonates diagnosed with post-haemorrhagic hydrocephalus (PHH) are recognised to have particularly poor outcomes. This study assessed the impact of a number of variables on outcomes in this cohort, in particular the choice of shunt valve mechanism.

METHODS

Electronic case notes were retrospectively reviewed of all premature neonates admitted to our centre for management of hydrocephalus between 2012 and 2021. Data included (i) gestational age, (ii) birth weight, (iii) hydrocephalus aetiology, (iv) surgical intervention, (v) shunt system, (vi) 'surgical burden' and (vii) wound failure and infection rate. Data was handled in Microsoft Excel and statistical analysis performed in SPSS v27.0 RESULTS: N = 53 premature hydrocephalic patients were identified (n = 28 (52.8%) female). Median gestational age at birth was 27 weeks (range: 23-36 + 6 weeks), with n = 35 extremely preterm patients and median birth weight of 1.9 kg (range: 0.8-3.6 kg). Total n = 99 programmable valves were implanted (n = 28 (28.3%) de novo, n = 71 (71.2%) revisions); n = 28 (28.3%) underwent n ≥ 1 pressure alterations, after which n = 21 (75%) patients had symptoms improve. In n = 8 patients exchanged from fixed to programmable valves, a mean reduction of 1.9 revisions per patient after exchange was observed (95%CI: 0.36-3.39, p = 0.02). Mean overall shunt survival was 39.5 weeks (95%CI: 30.6-48.5); 33.2 weeks (95%CI: 25.2-41.1) in programmable valves and 35.1 weeks (95%CI: 19.5-50.6) in fixed pressure (p = 0.22) with 12-month survival rates of 25.7% and 24.7%, respectively (p = 0.22). Shorter de novo shunt survival was associated with higher operation count overall (Pearson's R: - 0.54, 95%CI: - 0.72 to - 0.29, p < 0.01). Wound failure, gestational age and birth weight were significantly associated with shorter de novo shunt survival in a Cox regression proportional hazards model; gestational age had the greatest impact on shunt survival (Exp(B): 0.71, 95%CI: 0.63-0.81, p < 0.01).

CONCLUSION

Hydrocephalus is especially challenging in extreme prematurity, with a shorter de novo shunt survival associated with higher number of future revisions. Programmable valves provide flexibility with regard to pressure setting, with the potential for fewer shunt revisions in this complex cohort.

Posttraumatic hydrocephalus: Recent advances and new therapeutic strategies

Background

Hydrocephalus or ventriculomegaly is a condition brought on by an overabundance of cerebrospinal fluid (CSF) in the ventricular system. The major contributor to posttraumatic hydrocephalus (PTH) is traumatic brain injuries (TBIs), especially in individuals with occupations set in industrial settings. A variety of criteria have been employed for the diagnosis of PTH, including the combination of neurological symptoms like nerve deficits and headache, as well as an initial improvement followed by a worsened relapse of altered consciousness and neurological deterioration, which is detected by computed tomography-brain imaging that reveals gradual ventriculomegaly.

Aim

In this article, we discuss and summarize briefly the current understandings and advancements in the management of PTH.

Methods

The available literature for this review was searched on various bibliographic databases using an individually verified, prespecified approach. The level of evidence of the included studies was considered as per the Centre for Evidence-Based Medicine recommendations.

Results

The commonly practiced current treatment modality involves shunting CSF but is often associated with complications and recurrence. The lack of a definitive management strategy for PTH warrants the utilization of novel and innovative modalities such as stem cell transplantations and antioxidative stress therapies.

Conclusion

One of the worst complications of a TBI is PTH, which has a high morbidity and mortality rate. Even though there hasn't been a successful method in stopping PTH from happening, hemorrhage-derived blood, and its metabolic by-products, like iron, hemoglobin, free radicals, thrombin, and red blood cells, may be potential targets for PTH hindrance and management. Also, using stem cell transplantations in animal models and antioxidative stress therapies in future studies can lower PTH occurrence and improve its outcome. Moreover, the integration of clinical trials and theoretical knowledge should be encouraged in future research projects to establish effective and updated management guidelines for PTH.

Therapeutic strategies to recover ependymal barrier after inflammatory damage: relevance for recovering neurogenesis during development

The epithelium covering the surfaces of the cerebral ventricular system is known as the ependyma, and is essential for maintaining the physical and functional integrity of the central nervous system. Additionally, the ependyma plays an essential role in neurogenesis, neuroinflammatory modulation and neurodegenerative diseases. Ependyma barrier is severely affected by perinatal hemorrhages and infections that cross the blood brain barrier. The recovery and regeneration of ependyma after damage are key to stabilizing neuroinflammatory and neurodegenerative processes that are critical during early postnatal ages. Unfortunately, there are no effective therapies to regenerate this tissue in human patients. Here, the roles of the ependymal barrier in the context of neurogenesis and homeostasis are reviewed, and future research lines for development of actual therapeutic strategies are discussed.

Outcomes of the 2019 hydrocephalus association workshop, "Driving common pathways: extending insights from posthemorrhagic hydrocephalus"

The Hydrocephalus Association (HA) workshop, Driving Common Pathways: Extending Insights from Posthemorrhagic Hydrocephalus, was held on November 4 and 5, 2019 at Washington University in St. Louis. The workshop brought together a diverse group of basic, translational, and clinical scientists conducting research on multiple hydrocephalus etiologies with select outside researchers. The main goals of the workshop were to explore areas of potential overlap between hydrocephalus etiologies and identify drug targets that could positively impact various forms of hydrocephalus. This report details the major themes of the workshop and the research presented on three cell types that are targets for new hydrocephalus interventions: choroid plexus epithelial cells, ventricular ependymal cells, and immune cells (macrophages and microglia).

Investigating Pathways of Ventilation Induced Brain Injury on Cerebral White Matter Inflammation and Injury After 24 h in Preterm Lambs

Initiation of respiratory support in the delivery room increases the risk and severity of brain injury in preterm neonates through two major pathways: an inflammatory pathway and a haemodynamic pathway. The relative contribution of each pathway on preterm brain injury is not known. We aimed to assess the role of the inflammatory and haemodynamic pathway on ventilation-induced brain injury (VIBI) in the preterm lamb. Fetal lambs (125 ± 1 day gestation) were exteriorised, instrumented and ventilated with a high tidal-volume (V_T) injurious strategy for 15 min either with placental circulation intact to induce the inflammatory pathway only (INJ_INF; n = 7) or umbilical cord occluded to induce both the inflammatory and haemodynamic pathways (INJ_INF+HAE; n = 7). Sham controls were exteriorised but not ventilated (SHAM; n = 5) while unoperated controls (UNOP; n = 7) did not undergo fetal instrumentation. Fetuses were returned in utero following intervention and the ewe allowed to recover. Arterial blood gases and plasma were sampled periodically. Twenty-four hours following intervention, lambs were delivered and maintained on non-injurious ventilation for ∼40 min then brains were collected post-mortem for immunohistochemistry and RT-qPCR to assess inflammation, vascular pathology and cell death within white matter regions. Compared to INJ_INF lambs, INJ_INF+HAE lambs achieved a consistently higher V_T during injurious ventilation and carotid blood flow was significantly lower than baseline by the end of ventilation. Throughout the 24 h recovery period, systemic arterial IL-6 levels of INJ_INF+HAE lambs were significantly higher than SHAM while there was no difference between INJ_INF and SHAM animals. At 24 h, mRNA expression levels of pro-inflammatory cytokines, tight junction proteins, markers of cell death, and histological injury indices of gliosis, blood vessel protein extravasation, oligodendrocyte injury and cell death were not different between groups. Injurious ventilation, irrespective of strategy, did not increase brain inflammation or injury 24 h later when compared to control animals. However, the haemodynamic pathway did influence carotid blood flow adaptations during injurious ventilation and increased systemic arterial IL-6 that may underlie long-term pathology. Future studies are required to further characterise the pathways and their long-term effects on VIBI.

Pharmacological neuroprotection and clinical trials of novel therapies for neonatal peri-intraventricular hemorrhage: a comprehensive review

Peri-intraventricular hemorrhage (PIVH) is a serious condition for preterm infants, caused by traumatic or spontaneous rupture of the germinal matrix (GM) capillary network in the cerebral ventricles. It is a common source of morbidity and mortality in neonates, and risk correlates with earlier delivery, low birth weight, maternal-fetal infection, and vital sign derangements, among others. PIVH typically occurs in the first 72 h of life, and symptoms, when present, manifest most commonly within the first week of life. Prevention remains the primary goal in management, predominantly via prolonging of gestation. Current therapy protocols are center-dependent without consistent consensus guidelines, but infant positioning, homeostatic stabilization, and neuroprotection offer potential options. In this update of pharmacologic neuroprotective therapies for PIVH, we highlight commonly utilized therapies and review the investigative literature. Further multi-institutional clinical trials and basic research studies are required.

A neonatal neuroNICU collaborative approach to neuromonitoring of posthemorrhagic ventricular dilation in preterm infants

Morbidity and mortality in prematurely born infants have significantly improved due to advancement in perinatal care, development of NeuroNICU collaborative multidisciplinary approaches, and evidence-based management protocols that have resulted from a better understanding of perinatal risk factors and neuroprotective treatments. In premature infants with intraventricular hemorrhage (IVH), the detrimental secondary effect of posthemorrhagic ventricular dilation (PHVD) on the neurodevelopmental outcome can be mitigated by surgical intervention, though management varies considerably across institutions. Any benefit derived from the use of neuromonitoring to optimize surgical timing and technique stands to improve neurodevelopmental outcome. In this review, we summarize (1) the approaches to surgical management of PHVD in preterm infants and outcome data; (2) neuromonitoring modalities and the effect of neurosurgical intervention on this data; (3) our resultant protocol for the monitoring and management of PHVD. In particular, our protocol incorporates cerebral near-infrared spectroscopy (NIRS) and transcranial doppler ultrasound (TCD) to better understand cerebral physiology and to enable the hypothesis-driven study of the management of PHVD. IMPACT: Review of the published literature concerning the use of near-infrared spectroscopy (NIRS) and a cerebral Doppler ultrasound to study the effect of cerebrospinal fluid drainage on infants with posthemorrhagic ventricular dilation. Presentation of our institution's evidence-based protocol for the use of NIRS and cerebral Doppler ultrasound to study the optimal neurosurgical treatment of posthemorrhagic ventricular dilation, an as yet inadequately studied area.

Every Country, Every Woman, Every Child; Group B Streptococcal Disease Worldwide Prematurity modifies the risk of long-term neurodevelopmental impairments after invasive Group B Streptococcus infections during infancy in Denmark and the Netherlands

Background

Preterm birth and neonatal infections are both associated with mortality and long-term neurodevelopmental impairments (NDIs). We examined whether the effect of invasive group B Streptococcus disease (iGBS) on mortality and long-term NDI differs for preterm and term infants, and whether co-occurrence of iGBS and prematurity leads to worse outcome.

Methods

Nationwide cohort studies of children with a history of iGBS were conducted using Danish and Dutch medical databases. Comparison cohorts of children without iGBS were matched on birth year/month, sex, and gestational age. Effects of iGBS on all-cause mortality and NDI were analyzed using Cox proportional hazards and logistic regression. Effect modification by prematurity was evaluated on additive and multiplicative scales.

Results

We identified 487 preterm and 1642 term children with a history of iGBS and 21 172 matched comparators. Dutch preterm children exposed to iGBS had the highest mortality rate by 3 months of age (671/1000 [95% CI, 412–929/1000] person-years). Approximately 30% of this mortality rate could be due to the common effect of iGBS and prematurity. Preterm children with iGBS had the highest NDI risk (8.8% in Denmark, 9.0% in the Netherlands). Of this NDI risk 36% (Denmark) and 60% (the Netherlands) might be due to the combined effect of iGBS and prematurity.

Conclusions

Prematurity is associated with iGBS development. Our study shows that it also negatively impacts outcomes of children who survive iGBS. Preterm infants would benefit from additional approaches to prevent maternal GBS colonization, as this decreases risk of both preterm birth and iGBS.

Cumulative Damage: Cell Death in Posthemorrhagic Hydrocephalus of Prematurity

Globally, approximately 11% of all infants are born preterm, prior to 37 weeks’ gestation. In these high-risk neonates, encephalopathy of prematurity (EoP) is a major cause of both morbidity and mortality, especially for neonates who are born very preterm (<32 weeks gestation). EoP encompasses numerous types of preterm birth-related brain abnormalities and injuries, and can culminate in a diverse array of neurodevelopmental impairments. Of note, posthemorrhagic hydrocephalus of prematurity (PHHP) can be conceptualized as a severe manifestation of EoP. PHHP impacts the immature neonatal brain at a crucial timepoint during neurodevelopment, and can result in permanent, detrimental consequences to not only cerebrospinal fluid (CSF) dynamics, but also to white and gray matter development. In this review, the relevant literature related to the diverse mechanisms of cell death in the setting of PHHP will be thoroughly discussed. Loss of the epithelial cells of the choroid plexus, ependymal cells and their motile cilia, and cellular structures within the glymphatic system are of particular interest. Greater insights into the injuries, initiating targets, and downstream signaling pathways involved in excess cell death shed light on promising areas for therapeutic intervention. This will bolster current efforts to prevent, mitigate, and reverse the consequential brain remodeling that occurs as a result of hydrocephalus and other components of EoP.

The duration of intrauterine development influences discrimination of speech prosody in infants

Auditory speech discrimination is essential for normal language development. Children born preterm are at greater risk of language developmental delays. Using functional near-infrared spectroscopy at term-equivalent age, the present study investigated early discrimination of speech prosody in 62 neonates born between week 23 and 41 of gestational age (GA). We found a significant positive correlation between GA at birth and neural discrimination of forward versus backward speech at term-equivalent age. Cluster analysis identified a critical threshold at around week 32 of GA, pointing out the existence of subgroups. Infants born before week 32 of GA exhibited a significantly different pattern of hemodynamic response to speech stimuli compared to infants born at or after week 32 of GA. Thus, children born before the GA of 32 weeks are especially vulnerable to early speech discrimination deficits. To support their early language development, we therefore suggest a close follow-up and additional speech and language therapy especially in the group of children born before week 32 of GA.

Efficacy and safety of intraventricular fibrinolytic therapy for post-intraventricular hemorrhagic hydrocephalus in extreme low birth weight infants: a preliminary clinical study

PURPOSE

To evaluate the efficacy and safety of our unique therapy for treating post-intraventricular hemorrhagic hydrocephalus (PIVHH) in low birth weight infants (LBWls) through an early stage fibrinolytic therapeutic strategy involving urokinase (UK) injection into the lateral ventricle, called the "Ventricular Lavage (VL) therapy."

METHODS

Overall, 43 consecutive infants with PIVHH were included. Most were extremely LBWIs (n = 39). Other cases included very LBWIs (n = 2) and full-term infants (n = 2). VL therapy involved continuous external ventricular drainage (EVD) management using a very fine catheter and intermittent slow injection of 6000 IU of UK every 3-6 h to actively dissolve hematomas.

RESULTS

Early EVD management (within 3 weeks of IVH onset) was performed in 25 infants, with combination VL therapy in 21 infants. Five initiated late EVD management (≥ 3 weeks after IVH onset); the remaining 13 were treated conservatively for several weeks, delaying surgical intervention. Eighteen of 21 (86%) infants who received VL therapy did not require permanent shunt surgery. There were no serious complications, including the absence of secondary hemorrhage and infection. Two-thirds of the infants treated in the late stages required permanent shunt, and various shunt-related complications frequently occurred. A good outcome occurred in 13/17 infants in the early treatment group, despite most subjects having an IVH grade IV, and in 6/15 in the late treatment group.

CONCLUSIONS

Permanent shunt surgery needs were dramatically reduced following early VL therapy, and functional outcomes were favorable. VL therapy might be a promising strategy that could lead to the development of new treatments for PIVHH.

Elevated Pro-Inflammatory Cell-Free MicroRNA Levels in Cerebrospinal Fluid of Premature Infants after Intraventricular Hemorrhage

Intraventricular hemorrhage (IVH) represents a high risk of neonatal mortality and later neurodevelopmental impairment in prematurity. IVH is accompanied with inflammation, hemolysis, and extracellular hemoglobin (Hb) oxidation. However, microRNA (miRNA) expression in cerebrospinal fluid (CSF) of preterm infants with IVH has been unknown. Therefore, in the present study, candidate pro-inflammatory cell-free miRNAs were analyzed in CSF samples from 47 preterm infants with grade III or IV IVH vs. clinical controls (n = 14). miRNAs were quantified by RT-qPCR, normalized to “spike-in” cel-miR-39. Oxidized Hb and total heme levels were determined by spectrophotometry as well as IL-8, VCAM-1, ICAM-1, and E-selectin concentrations by ELISA. To reveal the origin of the investigated miRNAs, controlled hemolysis experiments were performed in vitro; in addition, human choroid plexus epithelial cell (HCPEpiC) cultures were treated with metHb, ferrylHb, heme, or TNF-α to replicate IVH-triggered cellular conditions. Levels of miR-223, miR-155, miR-181b, and miR-126 as well as Hb metabolites along with IL-8 were elevated in CSF after the onset of IVH vs. controls. Significant correlations were observed among the miRNAs, oxidized Hb forms, and the soluble adhesion molecules. During the post-IVH follow-up, attenuated expression of miRNAs and protein biomarkers in CSF was observed upon elimination of Hb metabolites. These miRNAs remained unaffected by a series of artificially induced hemolysis, which excluded red blood cells as their origin, while stimulation of HCPEpiCs with oxidized Hb fractions and heme resulted in increased extracellular miRNA levels in the cell culture supernatant. Overall, the hemorrhage-induced CSF miRNAs reflected inflammatory conditions as potential biomarkers in preterm IVH.

Respiratory Support of the Preterm Neonate: Lessons About Ventilation-Induced Brain Injury From Large Animal Models

Many preterm neonates require mechanical ventilation which increases the risk of cerebral inflammation and white matter injury in the immature brain. In this review, we discuss the links between ventilation and brain injury with a focus on the immediate period after birth, incorporating respiratory support in the delivery room and subsequent mechanical ventilation in the neonatal intensive care unit. This review collates insight from large animal models in which acute injurious ventilation and prolonged periods of ventilation have been used to create clinically relevant brain injury patterns. These models are valuable resources in investigating the pathophysiology of ventilation-induced brain injury and have important translational implications. We discuss the challenges of reconciling lung and brain maturation in commonly used large animal models. A comprehensive understanding of ventilation-induced brain injury is necessary to guide the way we care for preterm neonates, with the goal to improve their neurodevelopmental outcomes.

Perinatal factors associated with amplitude-integrated electroencephalography abnormalities in preterm infants on the first day of life

OBJECTIVE

Evaluate the association between perinatal factors and amplitude-integrated electroencephalogram abnormalities in preterm infants on the first day of life.

METHODS

This was a cross-sectional study of 60 infants with gestational age between 23 and 32 weeks, without malformations. Infants were continuously monitored by amplitude-integrated electroencephalogram on the first day of life, for at least 3h. The tracings were recorded and analyzed in each column for the following: burst-suppression pattern, sleep-wake cycle, and amplitude of the lower margin (<3μV or <5μV). The association of maternal complications, mode of delivery, birth weight, gestational age, neonatal sex, resuscitation procedures, hypothermia on admission, and the Score for Neonatal Acute Physiology, Perinatal Extension, Version II [SNAPPE-II]) with amplitude-integrated electroencephalogram alterations was assessed by multiple logistic regression.

RESULTS

A discontinuous pattern occurred in 65% of infants, and a continuous pattern occurred in 23%. The burst-suppression pattern was associated with vaginal delivery (OR: 7.6; 95% CI: 1.1-53.1) and SNAPPE-II≥40 (OR: 13.1; 95% CI: 1.8-95.1). A lower margin of the amplitude-integrated electroencephalogram of <3μV was also associated with SNAPPE-II≥40 (OR: 10.6, 95% CI: 2.3-49.2), while a value <5μV was associated with lower GA (OR: 0.51, 95% CI: 0.34-0.76). There were no associations between the perinatal variables and the absence of a sleep-wake cycle in amplitude-integrated electroencephalogram recordings on the first day of life.

CONCLUSION

Biological variables and clinical severity are associated with electroencephalographic characteristics of preterm infants on the first day of life and should be considered in clinical practice when amplitude-integrated electroencephalogram is performed.

Surgical management of intraventricular hemorrhage and posthemorrhagic hydrocephalus in premature infants

Perinatal intraventricular hemorrhage (IVH) with or without development of posthemorrhagic hydrocephalus (PHH) in premature neonates may lead to severe neurological disability. Although the percentage of preterm infants developing IVH has been greatly reduced in the last three decades, increased survival of these very immature infants has meant that large IVH with subsequent PHH is still a serious unsolved problem. Early cerebrospinal fluid diversion as a temporizing measure or a permanent shunt is the treatment of choice. This review summarizes the surgical modalities, techniques, and their complications in the management of IVH and PHH in premature infants. Though there is no level-one evidence to support the superiority of any of the currently available managements in the initial treatment of PHH over others, this review aims to provide pediatric neurosurgeons a comprehensive understanding of the pros and cons of various surgical treatment modalities, focusing on the temporizing measures before the infants is heavy enough to undergo ventriculoperitoneal shunt insertion. Based on the patient's condition, the facility and man power of the institution with minimal complication rate, the pediatric neurosurgeons may choose the best initial approach for the management of IVH and PHH in premature infants.

Risk factors associated with conversion of an Ommaya reservoir to a permanent cerebrospinal fluid shunt in preterm posthemorrhagic hydrocephalus

OBJECTIVE

A considerable percentage of preterm infants with posthemorrhagic hydrocephalus initially managed with an Ommaya reservoir require a permanent CSF shunt. The objective of the study was to analyze possible risk factors associated with the need for converting an Ommaya reservoir to a permanent shunt.

METHODS

The authors retrospectively reviewed the clinical records of premature infants weighing 1500 g or less with posthemorrhagic hydrocephalus (Papile grades III and IV) managed with an Ommaya reservoir at their institution between 2002 and 2017.

RESULTS

Forty-six patients received an Ommaya reservoir. Five patients (10.9%) were excluded due to intraventricular infection during management with an Ommaya reservoir. Average gestational age and weight for the remaining 41 patients was 27 ± 1.8 weeks and 987 ± 209 grams, respectively. Thirty patients required a permanent shunt and 11 patients did not require a permanent shunt. The conversion rate from an Ommaya reservoir to a permanent shunt was 76.1%. Symptomatic persistent ductus arteriosus (PDA) was more frequent in the nonpermanent shunt group than in the shunt group (88.9% vs 50%, p = 0.04). The need for extraction of more than 10 ml/kg per day of CSF through the Ommaya reservoir was lower in the nonpermanent shunt group than in the shunt group (9.1% vs 51.7%, p = 0.015). CSF lactate was lower in the nonpermanent group than in the shunt group (mean 2.48 mg/dl vs 3.19 mg/dl; p = 0.004). A cutoff value of ≥ 2.8 mg/dl CSF lactate predicted the need for a permanent shunt with sensitivity and specificity of 82.4% and 80%, respectively. There were no significant differences in gestational age, sex, weight, Papile grade, ventricular index, or other biochemical markers. After the multivariate analysis, only CSF lactate ≥ 2.8 mg/dl was associated with a higher conversion rate to a permanent shunt.

CONCLUSIONS

This study showed that a high level of CSF lactate, absence of symptomatic PDA, and a higher CSF extraction requirement were associated with a higher likelihood of implanting a permanent CSF shunt. The authors believe these findings should be considered in future studies.

Cerebral venous volume changes and pressure autoregulation in critically ill infants

OBJECTIVE

To determine whether ventilator-related fluctuations in cerebral blood volume (CBV) are associated with cerebral pressure passivity.

STUDY DESIGN

In a prospective study of newborns undergoing positive-pressure ventilation, we calculated coherence between continuous mean arterial pressure (MAP) and cerebral near-infrared spectroscopy hemoglobin difference (HbD). Significant HbD-MAP coherence indicated cerebral pressure passivity. CBV changes were measured as the spectral power of total hemoglobin (S_HbT) at the ventilator frequency. A regression model tested whether S_HbT predicts cerebral pressure passivity and/or death/brain injury, controlling for birth gestational age and other factors.

RESULTS

We studied 68 subjects with prematurity (n = 19), congenital heart disease (n = 11), and hypoxic-ischemic encephalopathy (n = 38). S_HbT, sedative use, and pCO₂ were positively associated, and circulating hemoglobin negatively associated, with cerebral pressure passivity (p < 0.001), which was positively associated with brain injury (p < 0.001).

CONCLUSION

In sick newborns, ventilator-related CBV fluctuations may predispose to cerebral pressure passivity, which may predispose to an adverse neonatal outcome.

MR diffusion changes in the perimeter of the lateral ventricles demonstrate periventricular injury in post-hemorrhagic hydrocephalus of prematurity

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Diffusion MRI demonstrates PHH is associated with LVP microstructural injury.

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The greatest PHH-associated disruption occurs at the frontal and occipital horns.

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Greater ventricular size is associated with greater disruption.

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dMRI may provide useful biomarkers for PHH monitoring and intervention.

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The region of LVP injury encompasses neuroprogenitor regions.

Objectives

Injury to the preterm lateral ventricular perimeter (LVP), which contains the neural stem cells responsible for brain development, may contribute to the neurological sequelae of intraventricular hemorrhage (IVH) and post-hemorrhagic hydrocephalus of prematurity (PHH). This study utilizes diffusion MRI (dMRI) to characterize the microstructural effects of IVH/PHH on the LVP and segmented frontal-occipital horn perimeters (FOHP).

Study design

Prospective study of 56 full-term infants, 72 very preterm infants without brain injury (VPT), 17 VPT infants with high-grade IVH without hydrocephalus (HG-IVH), and 13 VPT infants with PHH who underwent dMRI at term equivalent. LVP and FOHP dMRI measures and ventricular size-dMRI correlations were assessed.

Results

In the LVP, PHH had consistently lower FA and higher MD and RD than FT and VPT (p<.050). However, while PHH FA was lower, and PHH RD was higher than their respective HG-IVH measures (p<.050), the MD and AD values did not differ. In the FOHP, PHH infants had lower FA and higher RD than FT and VPT (p<.010), and a lower FA than the HG-IVH group (p<.001). While the magnitude of AD in both the LVP and FOHP were consistently less in the PHH group on pairwise comparisons to the other groups, the differences were not significant (p>.050). Ventricular size correlated negatively with FA, and positively with MD and RD (p<.001) in both the LVP and FOHP. In the PHH group, FA was lower in the FOHP than in the LVP, which was contrary to the observed findings in the healthy infants (p<.001). Nevertheless, there were no regional differences in AD, MD, and RD in the PHH group.

Conclusion

HG-IVH and PHH results in aberrant LVP/FOHP microstructure, with prominent abnormalities among the PHH group, most notably in the FOHP. Larger ventricular size was associated with greater magnitude of abnormality. LVP/FOHP dMRI measures may provide valuable biomarkers for future studies directed at improving the management and neurological outcomes of IVH/PHH.

First clinical experience with the new noninvasive transfontanelle ICP monitoring device in management of children with premature IVH

We previously introduced a novel noninvasive technique of intracranial pressure (ICP) monitoring in children with open fontanelles. Within this study, we describe the first clinical implementation and results of this new technique in management of children with hydrocephalus caused by intraventricular hemorrhage (IVH). In neonates with posthemorrhagic hydrocephalus (PHH), an Ommaya reservoir was implanted for initial treatment of hydrocephalus. The ICP obtained noninvasively with our new device was measured before and after CSF removal and correlated to cranial ultra-sonographies. Six children with a mean age of 27.3 weeks and mean weight of 1082.3 g suffering from PHH were included in this study. We performed an overall of 30 aspirations due to ventricular enlargement. Before CSF removal, the mean ICP was 15.3 mmHg and after removal of CSF the mean ICP measured noninvasively decreased to 3.4 mmHg, p = 0.0001. The anterior horn width (AHW), which reflects early expansion of the ventricles, was before and after CSF removal 15.1 mm and 5.5 mm, respectively, p < 0.0006. There was a strong correlation between noninvasively measured ICP values and sonographically obtained AHW, r = 0.81. Ultimately, all children underwent ventriculoperitoneal shunt procedures. This is the first study providing proof for a noninvasively ICP-based approach for management of posthemorrhagic hydrocephalus in newborn children.

Evaluation of factors for poor outcome in preterm newborns with posthemorrhagic hydrocephalus associated with late-onset neonatal sepsis

Purpose

Preterm newborns, due to many factors, are at increased risk for poor neural development, intraventricular hemorrhages, infections, and higher rate of mortality. The aim of this study was to evaluate the risk factors associated with poor outcome in preterm neonates with late-onset neonatal sepsis (LONS) who had posthemorrhagic hydrocephalus and underwent neurosurgical procedures for treatment of the hydrocephalus.

Patients and methods

Preterm neonates who had undergone insertion of ventriculoperitoneal shunt or Ommaya reservoir, during the 10-year period at University Children's Hospital, were retrospectively analyzed. According to the presence or absence of LONS, patients were divided into LONS group and non-LONS group. In both groups, we analyzed demographic and clinical data as well as nondependent factors. Additionally, we evaluated the patients who had lethal outcome in respect to all the analyzed factors.

Results

A total of 74 patients were included in the study, 35 in LONS group and 39 in control group. Patients in LONS group were born significantly earlier with lower birth weight, needed significantly higher O₂ inspiratory concentration, and had longer duration of mechanical ventilation when compared to the nonseptic group. Five patients in LONS group had lethal outcome, and for these patients we identified a grade American Society of Anaesthesiologists score of 4 (P=0.000), ductus arteriosus persistens (P=0.000), bronchopulmonary dysplasia (P=0.003), and pneumothorax (P=0.003) as independent preoperative risk factors for lethal outcome.

Conclusion

Neurosurgical procedures are relatively safe in neonates with posthemorrhagic hydrocephalus without LONS after birth. However, if LONS is present, various conditions such as preoperative high grade American Society of Anaesthesiologists score, ductus arteriosus persistens, bronchopulmonary dysplasia, and pneumothorax markedly increase the risk for a lethal outcome after the operation.

Outcomes of preterm infants treated with hypothermia for hypoxic-ischemic encephalopathy

BACKGROUND

Therapeutic hypothermia reduces the risk of death, or moderate to severe neurodevelopmental impairment (NDI) in term infants with hypoxic-ischemic encephalopathy (HIE). Reports of its safety and efficacy in preterm infants are scarce.

OBJECTIVE

Report short and long-term outcomes of preterm infants with HIE who received therapeutic hypothermia.

METHODS

A retrospective cohort analysis of all preterm infants <36 weeks' gestation with HIE who received whole body hypothermia in a single center from January 2007 to April 2015. The primary outcome was death or moderate to severe NDI defined by moderate or severe cerebral palsy, severe hearing or visual impairment, or cognitive score < 85 on the Bayley Scales of Infant Development III (BSID III) at 18-24 months' adjusted age.

RESULTS

30 infants with a median gestational age and birthweight of 35 weeks' (range; 33-35) and 2575 g (1850-4840) and a median first postnatal blood pH of 6.81 (6.58-7.14). Complications included coagulopathy (50%), early clinical seizures (43.3%), arterial hypotension (40%), persistent metabolic acidosis (37%) and thrombocytopenia (20%). Four infants died before or soon after discharge (18.2%). Eighteen surviving infants (69.2%) had follow up data; 7 of them had moderate to severe NDI (38.9%). Cognitive, motor and language mean composite BSID III scores were 84 (54-110), 83 (46-118), and 78 (46-112). Death or moderate to severe NDI occurred in 11/22 (50%) infants with known outcomes.

CONCLUSION

Large randomized trials on efficacy and safety are needed in this highly vulnerable population as the incidence of complications and the combined outcome of death and NDI is concerning.

Glucocorticoids, antenatal corticosteroid therapy and fetal heart maturation

Glucocorticoids are essential in mammals to mature fetal organs and tissues in order to survive after birth. Hence, antenatal glucocorticoid treatment (termed antenatal corticosteroid therapy) can be life-saving in preterm babies and is commonly used in women at risk of preterm birth. While the effects of glucocorticoids on lung maturation have been well described, the effects on the fetal heart remain less clear. Experiments in mice have shown that endogenous glucocorticoid action is required to mature the fetal heart. However, whether the potent synthetic glucocorticoids used in antenatal corticosteroid therapy have similar maturational effects on the fetal heart is less clear. Moreover, antenatal corticosteroid therapy may increase the risk of cardiovascular disease in adulthood. Here, we present a narrative review of the evidence relating to the effects of antenatal glucocorticoid action on the fetal heart and discuss the implications for antenatal corticosteroid therapy.

Utility of prenatal Doppler ultrasound to predict neonatal impaired cerebral autoregulation

OBJECTIVE

Determine if abnormal prenatal Doppler ultrasound indices are predictive of postnatal impaired cerebral autoregulation.

STUDY DESIGN

Prospective cohort study of 46 subjects, 24⁰-29⁶ weeks' gestation. Utilizing near-infrared spectroscopy and receiver-operating characteristic analysis, impaired cerebral autoregulation was defined as >16.5% time spent in a dysregulated state within 96 h of life. Normal and abnormal Doppler indices were compared for perinatal outcomes.

RESULTS

Subjects with abnormal cerebroplacental ratio (n = 12) and abnormal umbilical artery pulsatility index (n = 13) were likely to develop postnatal impaired cerebral autoregulation (p ≤ 0.02). Abnormal cerebroplacental ratio was associated with impaired cerebral autoregulation between 24 and 48 h of life (p = 0.016). These subjects have increased risk for fetal growth restriction, lower birth weight, lower Apgar scores, acidosis, and severe intraventricular hemorrhage and/or death (p < 0.05).

CONCLUSION

Abnormal cerebroplacental ratio and umbilical artery pulsatility index are associated with postnatal impairment in cerebral autoregulation and adverse outcome.

Opportunities in posthemorrhagic hydrocephalus research: outcomes of the Hydrocephalus Association Posthemorrhagic Hydrocephalus Workshop

The Hydrocephalus Association Posthemorrhagic Hydrocephalus Workshop was held on July 25 and 26, 2016 at the National Institutes of Health. The workshop brought together a diverse group of researchers including pediatric neurosurgeons, neurologists, and neuropsychologists with scientists in the fields of brain injury and development, cerebrospinal and interstitial fluid dynamics, and the blood-brain and blood-CSF barriers. The goals of the workshop were to identify areas of opportunity in posthemorrhagic hydrocephalus research and encourage scientific collaboration across a diverse set of fields. This report details the major themes discussed during the workshop and research opportunities identified for posthemorrhagic hydrocephalus. The primary areas include (1) preventing intraventricular hemorrhage, (2) stopping primary and secondary brain damage, (3) preventing hydrocephalus, (4) repairing brain damage, and (5) improving neurodevelopment outcomes in posthemorrhagic hydrocephalus.

Time-to-event analysis of surgically treated posthemorrhagic hydrocephalus in preterm infants: a single-institution retrospective study

PURPOSE

The purpose of this study is to report time points relevant to the neurosurgical management of posthemorrhagic hydrocephalus (PHH).

METHODS

Data were collected retrospectively on 104 preterm infants with intraventricular hemorrhage (IVH) who received neurosurgical intervention for PHH at St. Louis Children's Hospital from 1994 to 2016. Kaplan-Meier curves were constructed for various endpoints.

RESULTS

IVH grade on head ultrasound obtained through routine clinical care was II, III, and IV in 5 (4.8%), 33 (31.7%), and 66 (63.5%) of the patients, respectively. Neither IVH size nor location appeared to affect development of PHH. Days from birth to IVH, ventriculomegaly, temporizing neurosurgical procedure (TNP), and permanent neurosurgical intervention were 2.0 (95% CI 1.7-2.3), 3.0 (2.5-3.5), 24.0 (22.2-25.8), and 101.0 (90.4-111.6), respectively. Grades III and IV IVH did not differ in age at IVH diagnosis (Χ ² (1 d.f.) = 1.32, p = 0.25), ventriculomegaly (Χ ² = 0.73, p = 0.40), TNP (Χ ² = 0.61, p = 0.43), or permanent intervention (Χ ² = 2.48, p = 0.17). Ventricular reservoirs and ventriculosubgaleal shunts were used in 71 (68.3%) and 30 (28.8%), respectively. Eighty (76.9%) of the patients ultimately received a VPS. Five (4.8%) underwent a primary endoscopic third ventriculostomy (ETV), and two (1.9%) had ETV for a revision procedure. Four of the seven ETVs had choroid plexus cauterization.

CONCLUSIONS

Although most infants who develop IVH and ventriculomegaly will do so within a few days of birth, at-risk infants should be observed for at least 4 weeks with serial head ultrasounds to monitor for PHH requiring surgery.

Prematurity and brain perfusion: Arterial spin labeling MRI

Purpose

Abnormal brain perfusion is a critical mechanism in neonatal brain injury. The aim of the present study was to compare Cerebral Blood Flow (CBF) evaluated with ASL MRI in three groups of neonates: preterms without brain lesions on MRI (PN), preterms with periventricular white matter lesions (PNp) and term neonates with normal MRI (TN). The correlation between CBF and clinical outcome was explored.

Materials and methods

The institutional review board approved this prospective study and waived informed consent. The perfusion ASL data from 49 consecutive preterm neonates (PN) studied at term-equivalent age and 15 TN were evaluated. Statistically significant differences in gray matter CBF were evaluated by using a linear mixed-model analysis and Mann-Whitney U test. Logistic regression analysis was used to assess the relation between CBF and neuromotor outcome at 12 months.

Results

Comparison of means indicated that the CBF of the whole brain were significantly higher in PN compared to TN (P = 0.011). This difference remained significant when considering the frontal (P = 0.038), parietal (P = 0.002), temporal (P = 0.030), occipital (P = 0.041) and cerebellar (P = 0.010) gray matter. In the PN group, lower CBF in basal ganglia was associated with a worse neuromotor outcome (P = 0.012).

Conclusions

ASL MRI demonstrated differences in brain perfusion of the basal ganglia between PN and TN. In PN, a positive correlation between CBF and neuromotor outcome was demonstrated in this area.

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Different ASL cerebral perfusion between preterm and term neonates

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Global reduction of CBF values in preterm neonates with white matter lesions

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ASL identifies preterm neonates at higher risk for sub-optimal neuromotor development.

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Worst 12-months neuromotor outcome in preterm neonates with lower CBF of basal ganglia

Early postnatal illness severity scores predict neurodevelopmental impairments at 10 years of age in children born extremely preterm

OBJECTIVE

A neonatal illness severity score, The Score for Neonatal Acute Physiology-II (SNAP-II), predicts neurodevelopmental impairments at two years of age among children born extremely preterm. We sought to evaluate to what extent SNAP-II is predictive of cognitive and other neurodevelopmental impairments at 10 years of age.

STUDY DESIGN

In a cohort of 874 children born before 28 weeks of gestation, we prospectively collected clinical, physiologic and laboratory data to calculate SNAP-II for each infant. When the children were 10 years old, examiners who were unaware of the child's medical history assessed neurodevelopmental outcomes, including neurocognitive, gross motor, social and communication functions, diagnosis and treatment of seizures or attention deficit hyperactivity disorder (ADHD), academic achievement, and quality of life. We used logistic regression to adjust for potential confounders.

RESULTS

An undesirably high SNAP-II (⩾30), present in 23% of participants, was associated with an increased risk of cognitive impairment (IQ, executive function, language ability), adverse neurological outcomes (epilepsy, impaired gross motor function), behavioral abnormalities (attention deficit disorder and hyperactivity), social dysfunction (autistic spectrum disorder) and education-related adversities (school achievement and need for educational supports. In analyses that adjusted for potential confounders, Z-scores ⩽-1 on 11 of 18 cognitive outcomes were associated with SNAP-II in the highest category, and 6 of 18 were associated with SNAP-II in the intermediate category. Odds ratios and 95% confidence intervals ranged from 1.4 (1.01, 2.1) to 2.1 (1.4, 3.1). Similarly, 2 of the 8 social dysfunctions were associated with SNAP-II in the highest category, and 3 of 8 were associated with SNAP-II in the intermediate category. Odds ratios and 95% confidence intervals were slightly higher for these assessments, ranging from 1.6 (1.1, 2.4) to 2.3 (1.2, 4.6).

CONCLUSION

Among very preterm newborns, physiologic derangements present in the first 12 postnatal hours are associated with dysfunctions in several neurodevelopmental domains at 10 years of age. We are unable to make inferences about causality.

Post-hemorrhagic hydrocephalus: Recent advances and new therapeutic insights

Post-hemorrhagic hydrocephalus (PHH), also referred to as progressive ventricular dilatation, is caused by disturbances in cerebrospinal fluid (CSF) flow or absorption following hemorrhage in the brain. As one of the most serious complications of neonatal/adult intraventricular hemorrhage (IVH), subarachnoid hemorrhage (SAH), and traumatic brain injury (TBI), PHH is associated with increased morbidity and disability of these events. Common sequelae of PHH include neurocognitive impairment, motor dysfunction, and growth impairment. Non-surgical measures to reduce increased intracranial pressure (ICP) in PHH have shown little success and most patients will ultimately require surgical management, such as external ventricular drainage and shunting which mostly by inserting a CSF drainage shunt. Unfortunately, shunt complications are common and the optimum time for intervention is unclear. To date, there remains no comprehensive strategy for PHH management and it becomes imperative that to explore new therapeutic targets and methods for PHH. Over past decades, increasing evidence have indicated that hemorrhage-derived blood and subsequent metabolic products may play a key role in the development of IVH-, SAH- and TBI-associated PHH. Several intervention strategies have recently been evaluated and cross-referenced. In this review, we summarized and discussed the common aspects of hydrocephalus following IVH, SAH and TBI, relevant experimental animal models, clinical translation of in vivo experiments, and potential preventive and therapeutic targets for PHH.

Outcomes of intraventricular hemorrhage and posthemorrhagic hydrocephalus in a population-based cohort of very preterm infants born to residents of Nova Scotia from 1993 to 2010

OBJECT Intraventicular hemorrhage (IVH) is a common complication of preterm birth, and the prognosis of IVH is incompletely characterized. The objective of this study was to describe the outcomes of IVH in a population-based cohort with minimal selection bias. METHODS All very preterm (≥ 30 completed weeks) patients born in the province of Nova Scotia were included in a comprehensive database. This database was screened for infants born to residents of Nova Scotia from January 1, 1993, to December 31, 2010. Among very preterm infants successfully resuscitated at birth, the numbers of infants who died, were disabled, developed cerebral palsy, developed hydrocephalus, were blind, were deaf, or had cognitive/language scores assessed were analyzed by IVH grade. The relative risk of each outcome was calculated (relative to the risk for infants without IVH). RESULTS Grades 2, 3, and 4 IVH were significantly associated with an increased overall mortality, primarily in the neonatal period, and the risk increased with increasing grade of IVH. Grade 4 IVH was significantly associated with an increased risk of disability (RR 2.00, p < 0.001), and the disability appeared to be primarily due to cerebral palsy (RR 6.07, p < 0.001) and cognitive impairment (difference in mean MDI scores between Grade 4 IVH and no IVH: -19.7, p < 0.001). No infants with Grade 1 or 2 IVH developed hydrocephalus, and hydrocephalus and CSF shunting were not associated with poorer outcomes when controlling for IVH grade. CONCLUSIONS Grades 1 and 2 IVH have much better outcomes than Grades 3 or 4, including a 0% risk of hydrocephalus in the Grade 1 and 2 IVH cohort. Given the low risk of selection bias, the results of this study may be helpful in discussing prognosis with families of very preterm infants diagnosed with IVH.

Temporal trends of intraventricular hemorrhage of prematurity in Nova Scotia from 1993 to 2012

OBJECT Intraventicular hemorrhage (IVH) and posthemorrhagic hydrocephalus (PHH) are common in premature newborns. The epidemiology of these conditions has been described, but selection bias remains a significant concern in many studies. The goal of this study was to review temporal trends in the incidence of IVH, PHH, and shunt surgery in a population-based cohort of very preterm infants with no selection bias. METHODS All very preterm infants (gestational age ≥ 20 and ≤ 30 weeks) born from 1993 onward to residents of Nova Scotia were evaluated by the IWK Health Centre's Perinatal Follow-Up Program, and were entered in a database. Infants born to residents of Nova Scotia from January 1, 1993, to December 31, 2012, were included in this study. The incidences of IVH, PHH, and shunt surgery were calculated, basic demographic information was described, and chi-square test for trends over time was determined. RESULTS Of 1334 successfully resuscitated very preterm infants who survived to their initial screening ultrasound, 407 (31%) had an IVH, and 149 (11%) had an IVH Grade 3 or 4. No patients with IVH Grade 1 or 2 developed PHH. The percentage of very preterm infants with IVH Grade 3 or 4 has significantly increased over time (p = 0.013), as have the incidence of PHH and shunt surgery (p = 0.001 and p = 0.011, respectively) in infants with Grade 3 or 4 IVH. The proportion of patients with PHH receiving a shunt has not changed over time (p = 0.813). CONCLUSIONS The increasing incidence of high-grade IVH-and PHH and shunt surgery in infants with high-grade IVH-over time is worrisome. This study identifies a number of associated factors, but further research to identify preventable and treatable causal factors is warranted.

Ventricular reservoir versus ventriculosubgaleal shunt for posthemorrhagic hydrocephalus in preterm infants: infection risks and ventriculoperitoneal shunt rate

OBJECT

The most common neurosurgical condition observed in preterm infants is intraventricular hemorrhage (IVH), which often results in posthemorrhagic hydrocephalus (PHH). These conditions portend an unfavorable prognosis; therefore, the potential for poor neurodevelopmental outcomes necessitates a better understanding of the comparative effectiveness of 2 temporary devices commonly used before the permanent insertion of a ventriculoperitoneal (VP) shunt: the ventricular reservoir and the ventriculosubgaleal shunt (VSGS).

METHODS

The authors analyzed retrospectively collected information for 90 patients with IVH and PHH who were treated with insertion of a ventricular reservoir (n = 44) or VSGS (n = 46) at their institution over a 14-year period.

RESULTS

The mean gestational age and weight at device insertion were lower for VSGS patients (30.1 ± 1.9 weeks, 1.12 ± 0.31 kg) than for reservoir patients (31.8 ± 2.9 weeks, 1.33 ± 0.37 kg; p = 0.002 and p = 0.004, respectively). Ventricular reservoir insertion was predictive of more CSF taps prior to VP shunt placement compared with VSGS placement (10 ± 8.7 taps vs 1.6 ± 1.7 taps, p < 0.001). VSGS patients experienced a longer time interval prior to VP shunt placement than reservoir patients (80.8 ± 67.5 days vs 48.8 ± 26.4 days, p = 0.012), which corresponded to VSGS patients gaining more weight by the time of shunt placement than reservoir patients (3.31 ± 2.0 kg vs 2.42 ± 0.63 kg, p = 0.016). Reservoir patients demonstrated a trend toward more positive CSF cultures compared with VSGS patients (n = 9 [20.5%] vs n = 5 [10.9%], p = 0.21). There were no significant differences in the rates of overt device infection requiring removal (reservoir, 6.8%; VSGS, 6.5%), VP shunt insertion (reservoir, 77.3%; VSGS, 76.1%), or early VP shunt infection (reservoir, 11.4%; VSGS, 13.0%) between the 2 cohorts.

CONCLUSIONS

Although the rates of VP shunt requirement and device infection were similar between patients treated with the reservoir versus the VSGS, VSGS patients were significantly older and had achieved greater weights at the time of VP shunt insertion. The authors' results suggest that the VSGS requires less labor-intensive management by ventricular tapping; the VSGS patients also attained higher weights and more optimal surgical candidacy at the time of VP shunt insertion. The potential differences in long-term developmental and neurological outcomes between VSGS and reservoir placement warrant further study.

Neonatal neurosonography

Neonatal neurosonography is used commonly to evaluate the central nervous system in the neonatal intensive care setting. The procedure can be performed at the bedside in these critically ill patients who may suffer from hemodynamic and thermoregulatory instability and often require mechanical ventilation. This article reviews current recommendations regarding neurosonography technique, pathophysiology, and imaging of intracranial insults including hemorrhage, white matter injury, infarction, and hypoxic-ischemic encephalopathy.

Endoscopic third ventriculostomy and choroid plexus cauterization in posthemorrhagic hydrocephalus of prematurity

OBJECT

The aim of this study was to determine the role of endoscopic third ventriculostomy and choroid plexus cauterization (ETV/CPC) in the management of posthemorrhagic hydrocephalus of prematurity (PHHP) and to analyze which factors affect patient outcomes.

METHODS

This study retrospectively reviewed medical records of 27 premature infants with intraventricular hemorrhage (IVH) and hydrocephalus treated with ETV and CPC from 2008 to 2011. All patients were evaluated using MRI before the procedure to verify the anatomical feasibility of ETV/CPC. Endoscopic treatment included third ventriculostomy, septostomy, and bilateral CPC. After ETV/CPC, all patients underwent follow-up for a period of 6-40 months (mean 16.2 months). The procedure was considered a failure if the patient subsequently required a shunt. The following factors were analyzed to determine a relationship to patient outcomes: gestational age at birth, corrected age and weight at surgery, timing of surgery after birth, grade of IVH, the status of the prepontine cistern and cerebral aqueduct on MRI, need for a ventricular access device prior to the endoscopic procedure, and scarring of the prepontine cistern noted at surgery.

RESULTS

Seventeen (63%) of 27 patients required a shunt after ETV/CPC, and 10 patients did not require further CSF diversion. Several factors studied were associated with a higher rate of ETV/CPC failure: Grade IV hemorrhage, weight 3 kg or less and age younger than 3 months at the time of surgery, need for reservoir placement, and presence of a normal cerebral aqueduct. Two factors were found to be statistically significant: the patient's corrected gestational age of less than 0 weeks at surgery and a narrow prepontine cistern on MRI. The majority (83%) of ETV/CPC failures occurred in the first 3 months after the procedure. None of the patients had a complication directly related to the procedure.

CONCLUSIONS

Endoscopic third ventriculostomy/CPC is a safe initial procedure for hydrocephalus in premature infants with IVH and hydrocephalus, obviating the need for a shunt in selected patients. Even though the success rate is low (37%), the lower rate of complications in comparison with shunt treatment may justify this procedure in the initial management of hydrocephalus. As several of the studied factors have shown influence on the outcome, patient selection based on these observations might increase the success rate.

Ultrasound-guided neuronavigation improves safety of ventricular catheter insertion in preterm infants

BACKGROUND

Intra-ventricular hemorrhage (IVH) is a frequent cause of shunt-dependent hydrocephalus. The management of IVH in preterm babies remains a challenge both for neonatologists and pediatric neurosurgeons, compounded by the lack of low-risk, validated therapy techniques.

OBJECTIVE

The aim of this study was to evaluate the feasibility and safety of a novel technique involving the ultrasound-guided placement of a central catheter connected with a Rickham-Capsule in a cohort of preterm, low-birth-weight babies with post-hemorrhagic hydrocephalus (PHH).

METHODS

Eight preterm infants with PHH in which a Rickham-Capsule was placed from 2008-2012 were included. Conventional surgical techniques were used in four preterm infants; whereas in the other four preterm babies ultrasound guided catheter placement was performed with an 8 MegaHertz (MHz) micro convex transducer from LOGIQ 9, GE Healthcare; whereby the anterior fontanel was used as an acoustic window.

RESULTS

Overall gestational age was 24-31 weeks, mean age at operation was 20.1 (7-36) days, mean birth weight 972.5±370 g, mean weight at first surgical intervention 1023.75±400.4 g. Six patients had bilateral IVH II-III°, two patients had parenchymal involvement. Using the conventional approach, incorrect catheter placement occurred in one of four patients below 1000 g, whereas none of the ultrasound guided cases needed correction.

CONCLUSIONS

Ultrasound-guided neuronavigation represents a relevant tool in the treatment of hydrocephalus in preterm infants through increased accuracy in placement of a central catheter connected to a Rickham-Capsule. The benefit of utilizing this form of neuronavigation needs to be assessed through corresponding standardized studies.

Neonatal posthemorrhagic hydrocephalus from prematurity: pathophysiology and current treatment concepts

OBJECT

Preterm infants are at risk for perinatal complications, including germinal matrix-intraventricular hemorrhage (IVH) and subsequent posthemorrhagic hydrocephalus (PHH). This review summarizes the current understanding of the epidemiology, pathophysiology, management, and outcomes of IVH and PHH in preterm infants.

METHODS

The MEDLINE database was systematically searched using terms related to IVH, PHH, and relevant neurosurgical procedures to identify publications in the English medical literature. To complement information from the systematic search, pertinent articles were selected from the references of articles identified in the initial search.

RESULTS

This review summarizes the current knowledge regarding the epidemiology and pathophysiology of IVH and PHH, primarily using evidence-based studies. Advances in obstetrics and neonatology over the past few decades have contributed to a marked improvement in the survival of preterm infants, and neurological morbidity is also starting to decrease. The incidence of IVH is declining, and the incidence of PHH will likely follow. Currently, approximately 15% of preterm infants who suffer severe IVH will require permanent CSF diversion. The clinical presentation and surgical management of symptomatic PHH with temporary ventricular reservoirs (ventricular access devices) and ventriculosubgaleal shunts and permanent ventriculoperitoneal shunts are discussed. Preterm infants who develop PHH that requires surgical treatment remain at high risk for other related neurological problems, including cerebral palsy, epilepsy, and cognitive and behavioral delay. This review highlights numerous opportunities for further study to improve the care of these children.

CONCLUSIONS

A better grasp of the pathophysiology of IVH is beginning to impact the incidence of IVH and PHH. Neonatologists conduct rigorous Class I and II studies to advance the outcomes of preterm infants. The need for well-designed multicenter trials is essential because of the declining incidence of IVH and PHH, variations in referral patterns, and neonatal ICU and neurosurgical management. Well-designed multicenter trials will eventually produce evidence to enable neurosurgeons to provide their smallest, most vulnerable patients with the best practices to minimize perioperative complications and permanent shunt dependence, and most importantly, optimize long-term neurodevelopmental outcomes.

Neonatal blood pressure support: the use of inotropes, lusitropes, and other vasopressor agents

A solid understanding of the mechanisms of action of cardiovascular medications used in clinical practice along with efforts to develop comprehensive hemodynamic monitoring systems to improve the ability to accurately identify the underlying pathophysiology of cardiovascular compromise are essential in the management of neonates with shock. This article reviews the mechanisms of action of the most frequently used cardiovascular medications in neonates. Because of paucity of data from controlled clinical trials, evidence-based recommendations for the clinical use of these medications could not be made. Careful titration of the given medication with close monitoring of the cardiovascular response might improve the effectiveness and decrease the risks associated with administration of these medications.

Early postnatal hypotension is not associated with indicators of white matter damage or cerebral palsy in extremely low gestational age newborns

OBJECTIVE

To evaluate, in extremely low gestational age newborns (ELGANs), relationships between indicators of early postnatal hypotension and cranial ultrasound indicators of cerebral white matter damage imaged in the nursery and cerebral palsy diagnoses at 24 months follow-up.

STUDY DESIGN

The 1041 infants in this prospective study were born at <28 weeks gestation, were assessed for three indicators of hypotension in the first 24 postnatal hours, had at least one set of protocol cranial ultrasound scans and were evaluated with a structured neurological exam at 24 months corrected age. Indicators of hypotension included: (1) lowest mean arterial pressure (MAP) in the lowest quartile for gestational age; (2) treatment with a vasopressor; and (3) blood pressure lability, defined as the upper quartile of the difference between each infant's lowest and highest MAP. Outcomes included indicators of cerebral white matter damage, that is, moderate/severe ventriculomegaly or an echolucent lesion on cranial ultrasound and cerebral palsy diagnoses at 24 months gestation. Logistic regression was used to evaluate relationships among hypotension indicators and outcomes, adjusting for potential confounders.

RESULT

Twenty-one percent of surviving infants had a lowest blood pressure in the lowest quartile for gestational age, 24% were treated with vasopressors and 24% had labile blood pressure. Among infants with these hypotension indicators, 10% percent developed ventriculomegaly and 7% developed an echolucent lesion. At 24 months follow-up, 6% had developed quadriparesis, 4% diparesis and 2% hemiparesis. After adjusting for confounders, we found no association between indicators of hypotension, and indicators of cerebral white matter damage or a cerebral palsy diagnosis.

CONCLUSION

The absence of an association between indicators of hypotension and cerebral white matter damage and or cerebral palsy suggests that early hypotension may not be important in the pathogenesis of brain injury in ELGANs.

Early blood gas abnormalities and the preterm brain

The authors explored associations between blood gas abnormalities in more than 1,000 preterm infants during the first postnatal days and indicators of neonatal brain damage. During 2002-2004, women delivering infants before 28 weeks' gestation at one of 14 participating institutions in 5 US states were asked to enroll in the study. The authors compared infants with blood gas values in the highest or lowest quintile for gestational age and postnatal day (extreme value) on at least 1 of the first 3 postnatal days with the remainder of the subjects, with separate analyses for blood gas abnormalities on multiple days and for partial pressure of oxygen in the alveolar gas of <35. Outcomes analyzed were ventriculomegaly and an echolucent lesion on an ultrasound scan in the neonatal intensive care unit, and cerebral palsy, microcephaly, and a low score on a Bayley Scale of Infant Development at 24 months. Every blood gas derangement (hypoxemia, hyperoxemia, hypocapnia, hypercapnia, and acidosis) was associated with multiple indicators of brain damage. However, for some, the associations were seen with only 1 day of exposure; others were evident with 2 or more days' exposure. Findings suggest that individual blood gas derangements do not increase brain damage risk. Rather, the multiple derangements associated with indicators of brain damage might be indicators of immaturity/vulnerability and illness severity.