Poor correlation between head circumference and cranial ultrasound findings in premature infants with intraventricular hemorrhage

Prediction of short- and long-term outcomes using pre-operative ventricular size in infants with post-hemorrhagic ventricular dilation

PURPOSE

Post-hemorrhagic ventricular dilation (PHVD) leads to developmental delays in premature infants, yet the optimal timing of neurosurgical interventions is unknown. Neuroimaging modalities have emerged to delineate injury and follow the progression of PHVD. Fronto-temporal horn ratio (FTHR) is used as a marker of ventricular dilation and can be a standardized tool to direct the timing of neurosurgical intervention. Our study determined a pre-operative FTHR measurement threshold to predict short- and long-term outcomes.

METHODS

This is a retrospective cohort study of premature infants with severe intraventricular hemorrhage (IVH) who developed PHVD requiring neurosurgical intervention and were treated in a level IV NICU between 2012 and 2019. Receiver operating characteristic (ROC) curve and area under the curve (AUC) analyses were performed to evaluate the accuracy of pre-operative FTHR for predicting developmental delay. In-hospital outcomes and developmental assessments were analyzed.

RESULTS

We reviewed 121 charts of infants with IVH and identified 43 infants with PHVD who required neurosurgical intervention. We found FTHR measurements were an excellent predictor of cognitive and motor delay with an AUC of 0.89 and 0.88, respectively. An average pre-operative FTHR of ≥ 0.67 was also associated with worse lung and feeding outcomes. There was excellent inter-observer reliability of individual components of FTHR measurements.

CONCLUSIONS

Early intervention for PHVD is ideal but not always practical. Identification of ventricular size thresholds associated with better outcomes is needed to direct timing of neurosurgical intervention.

Ratios of head circumference to ventricular size vary over time and predict eventual need for CSF diversion in intraventricular hemorrhage of prematurity

PURPOSE

Intraventricular hemorrhage (IVH) of prematurity can lead to hydrocephalus, sometimes necessitating permanent cerebrospinal fluid (CSF) diversion. We sought to characterize the relationship between head circumference (HC) and ventricular size in IVH over time to evaluate the clinical utility of serial HC measurements as a metric in determining the need for CSF diversion.

METHODS

We included preterm infants with IVH born between January 2000 and May 2020. Three measures of ventricular size were obtained: ventricular index (VI), Evan's ratio (ER), and frontal occipital head ratio (FOHR). The Pearson correlations (r) between the initial (at birth) paired measurements of HC and ventricular size were reported. Multivariable longitudinal regression models were fit to examine the HC:ventricle size ratio, adjusting for the age of the infant, IVH grade (I/II vs. III/IV), need for CSF diversion, and sex.

RESULTS

A total of 639 patients with an average gestational age of 27.5 weeks were included. IVH grade I/II and grade III/IV patients had a positive correlation between initial HC and VI (r = 0.47, p < 0.001 and r = 0.48, p < 0.001, respectively). In our longitudinal models, patients with a low-grade IVH (I/II) had an HC:VI ratio 0.52 higher than those with a high-grade IVH (p-value < 0.001). Patients with low-grade IVH had an HC:ER ratio 12.94 higher than those with high-grade IVH (p-value < 0.001). Patients with low-grade IVH had a HC:FOHR ratio 12.91 higher than those with high-grade IVH (p-value < 0.001). Infants who did not require CSF diversion had an HC:VI ratio 0.47 higher than those who eventually did (p < 0.001). Infants without CSF diversion had an HC:ER ratio 16.53 higher than those who received CSF diversion (p < 0.001). Infants without CSF diversion had an HC:FOHR ratio 15.45 higher than those who received CSF diversion (95% CI (11.34, 19.56), p < 0.001).

CONCLUSIONS

There is a significant difference in the ratio of HC:VI, HC:ER, and HC:FOHR size between patients with high-grade IVH and low-grade IVH. Likewise, there is a significant difference in HC:VI, HC:ER, and HC:FOHR between those who did and did not have CSF diversion. The routine assessments of both head circumference and ventricle size by ultrasound are important clinical tools in infants with IVH of prematurity.

Three-dimensional cranial ultrasound and functional near-infrared spectroscopy for bedside monitoring of intraventricular hemorrhage in preterm neonates

Germinal Matrix-Intraventricular Hemorrhage (GMH-IVH) remains a significant cause of adverse neurodevelopment in preterm infants. Current management relies on 2-dimensional cranial ultrasound (2D cUS) ventricular measurements. Reliable biomarkers are needed to aid in the early detection of posthemorrhagic ventricular dilatation (PHVD) and subsequent neurodevelopment. In a prospective cohort study, we incorporated 3-dimensional (3D) cUS and functional near-infrared spectroscopy (fNIRS) to monitor neonates with GMH-IVH. Preterm neonates (≤ 32 weeks' gestation) were enrolled following a GMH-IVH diagnosis. Neonates underwent sequential measurements: 3D cUS images were manually segmented using in-house software, and the ventricle volumes (VV) were extracted. Multichannel fNIRS data were acquired using a high-density system, and spontaneous functional connectivity (sFC) was calculated. Of the 30 neonates enrolled in the study, 19 (63.3%) had grade I-II and 11 (36.7%) grade III-IV GMH-IVH; of these, 7 neonates (23%) underwent surgical interventions to divert cerebrospinal fluid (CSF). In infants with severe GMH-IVH, larger VV were significantly associated with decreased |sFC|. Our findings of increased VV and reduced sFC suggest that regional disruptions of ventricular size may impact the development of the underlying white matter. Hence, 3D cUS and fNIRS are promising bedside tools for monitoring the progression of GMH-IVH in preterm neonates.

Variability in the diagnostic and management practices of post-hemorrhagic ventricular dilatation in very preterm infants across Canadian centers and comparison with European practices

OBJECTIVES

To investigate the variability in diagnostic and therapeutic approaches to posthemorrhagic ventricular dilatation (PHVD) among Canadian neonatal centers, and secondary exploration of differences in approaches between Canadian and European practices.

METHODS

We conducted a survey among Canadian tertiary neonatal centers on their local practices for managing very preterm infants with PHVD. The survey covered questions on the diagnostic criteria, timing and type of interventions and resources utilization (transfer to neurosurgical sites and neurodevelopmental follow-up). In a secondary exploration, Canadian responses were compared with responses to the same survey from European centers.

RESULTS

23/30 Canadian centers (77%) completed the survey. There was no consensus among Canadian centers on the criteria used for diagnosing PHVD or to initiate intervention. The therapeutic interventions also vary, both for temporizing procedures or permanent shunting. Compared to European practices, the Canadian approach relied less on the sole use of ultrasound criteria for diagnosing PHVD (43 vs 94%, p < 0.0001) or timing intervention (26 vs 63%, p = 0.007). Majority of European centers intervened early in the development of PHVD based on ultrasound parameters, whereas Canadian centers intervened based on clinical hydrocephalus, with fewer centers performing serial lumbar punctures prior to neurosurgical procedures (40 vs 81%, p = 0.003).

CONCLUSION

Considerable variability exists in diagnosis and management of PHVD in preterm infants among Canadian tertiary centers and between Canadian and European practices. Given the potential implications of the inter-center practice variability on the short- and long-term outcomes of preterm infants with PHVD, efforts towards evidence-based Canada-wide practice standardization are underway.

Epidemiology of post-hemorrhagic ventricular dilatation in very preterm infants

OBJECTIVE

To describe the incidence, trends, management's variability and short-term outcomes of preterm infants with severe post-hemorrhagic ventricular dilatation (sPHVD).

METHODS

We reviewed infants &lt;33 weeks' gestation who had PHVD and were admitted to the Canadian Neonatal Network between 2010 and 2018. We compared perinatal characteristics and short-term outcomes between those with sPHVD and those with mild/moderate PHVD and those with and without ventriculo-peritoneal (VP) shunt.

RESULTS

Of 29,417 infants, 2439 (8%) had PHVD; rate increased from 7.3% in 2010 to 9.6% in 2018 (P = 0.005). Among infants with PHVD, sPHVD (19%) and VP shunt (29%) rates varied significantly across Canadian centers and between geographic regions (P &lt; 0.01 and P = 0.0002). On multivariable analysis, sPHVD was associated with greater mortality, seizures and meningitis compared to mild/moderate PHVD.

CONCLUSIONS

Significant variability in sPHVD and VP shunt rates exists between centers and regions in Canada. sPHVD was associated with increased mortality and morbidities.

New insights into the management of post-hemorrhagic hydrocephalus

During the last decade, an increasing number of studies have been conducted to improve the outcome of post-hemorrhagic hydrocephalus (PHH), a complication of severe intraventricular hemorrhage (IVH) in preterm infants. Two randomized controlled trials have shown that treatment should be initiated prior to the onset of clinical symptoms. Ventricular access devices and subgaleal shunts are used as temporary neurosurgical interventions whereas ventriculoperitoneal shunts are performed for infants with progressive hydrocephalus. Recently, techniques such as neuro-endoscopic lavage have also been introduced to eliminate toxic blood products and debris from the cerebral ventricles and have shown promise in early clinical studies. The objective of this review is to provide an update on management of PHVD and PHH in the preterm infant.

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.

Post-hemorrhagic ventricular dilatation: inter-observer reliability of ventricular size measurements in extremely preterm infants

BACKGROUND

Post-hemorrhagic ventricular dilatation (PHVD) in preterm infants can be assessed with ventricular size indices from cranial ultrasound. We explored inter-observer reliability of these indices for prediction of severe PHVD.

METHODS

For all 139 infants with IVH, serial neonatal ultrasound at 3 time points (days 4-7, day 14, 36 weeks PMA) were assessed independently by 3 observers with differing levels of training/experience. Ventricular index (VI), anterior horn width (AHW), and fronto-temporal horn ratio (FTHR) were measured and used to diagnose PHVD. For all, inter-observer reliability and predictive values for receipt of surgical intervention were calculated.

RESULTS

Inter-observer reliability for all observers varied from poor to excellent, with higher reliability for VI/AHW (ICC 0.49-0.84/0.51-0.81) than FTHR (0.41-0.82), particularly from the second week. Good-excellent inter-expertise reliability was found between observers with ample experience/training (0.65-0.99), particularly for VI and AHW, while poor-moderate when comparing with an inexperienced observer (0.28-0.88). Slightly higher predictive value for PHVD intervention (n = 12) was found for AHW (AUC 0.86-0.96) than for VI and FTHR (0.80-0.96/0.80-0.95).

CONCLUSIONS

AHW and VI are highly reproducible in experienced hands compared to FTHR, with AHW from the second week onwards being the strongest predictor for receiving surgical intervention for severe PHVD. AHW may aid in early PHVD diagnosis and decision-making on intervention.

IMPACT

While ventricular size indices from serial cUS are superior to clinical signs of increased intracranial pressure to assess PHVD, questions remained on their inter-observer reproducibility and reliability to predict severity of PHVD. AHW and VI are highly reproducible when performed by experienced clinicians. AHW from the second week of birth is the strongest predictor of PHVD onset and severity. AHW, combined with VI, may aid in early PHVD diagnosis and decision-making on need for surgical intervention. Consistent use of these indices has the potential to improve PHVD management and therewith the long-term outcomes in preterm infants.

Acute brain inflammation, white matter oxidative stress, and myelin deficiency in a model of neonatal intraventricular hemorrhage

OBJECTIVE

Neonatal intraventricular hemorrhage (IVH) leads to posthemorrhagic hydrocephalus (PHH), brain injury, and long-term disability. Current therapy for IVH is based on treating PHH but does not address the underlying brain injury. In order to develop pharmacological treatment for IVH, there must be a better understanding of the underlying pathology of this disease. This study was designed to determine the time course of the acute inflammation and oxidative stress that may underlie the progressive pathology of IVH. The authors sought to understand the temporal relationships among inflammation, oxidative stress, and white matter pathology in a rat model of IVH.

METHODS

A rat model of IVH consisting of hemoglobin injection into the lateral ventricle was used. Tissue was analyzed via biochemical and histological methods to map the spatiotemporal distribution of innate immune activation and oxidative stress. White matter was quantified using both immunohistochemistry and Western blot for myelin basic protein (MBP) in the corpus callosum.

RESULTS

IVH led to acute induction of inflammatory cytokines, followed by oxidative stress. Oxidative stress was concentrated in white matter, adjacent to the lateral ventricles. Animals with IVH initially gained weight at a lower rate than control animals and had larger ventricles and less MBP than control animals.

CONCLUSIONS

Experimental IVH induces global inflammation throughout the brain and oxidative stress concentrated in the white matter. Both of these phenomena occur early after IVH. This has implications for human neonates with immature white matter that is exquisitely sensitive to inflammation and oxidative stress. Antiinflammatory or antioxidant therapy for IVH may need to be initiated early in order to protect developing white matter.

Treatment thresholds for intervention in posthaemorrhagic ventricular dilation: a randomised controlled trial

OBJECTIVE

To compare a low versus a higher threshold for intervention in preterm infants with posthaemorrhagic ventricular dilatation.

DESIGN

Multicentre randomised controlled trial (ISRCTN43171322).

SETTING

14 neonatal intensive care units in six countries.

PATIENTS

126 preterm infants ≤34 weeks gestation with ventricular dilatation after grade III-IV haemorrhage were randomised to low threshold (LT) (ventricular index (VI) >p97 and anterior horn width (AHW) >6 mm) or higher threshold (HT) (VI>p97+4 mm and AHW >10 mm).

INTERVENTION

Cerebrospinal fluid tapping by lumbar punctures (LPs) (max 3), followed by taps from a ventricular reservoir, to reduce VI, and eventually a ventriculoperitoneal (VP) shunt if stabilisation of the VI below the p97+4 mm did not occur.

COMPOSITE MAIN OUTCOME MEASURE

VP shunt or death.

RESULTS

19 of 64 (30%) LT infants and 23 of 62 (37%) HT infants were shunted or died (P=0.45). A VP shunt was inserted in 12/64 (19%) in the LT and 14/62 (23%) infants in the HT group. 7/12 (58%) LT infants and 1/14 (7%) HT infants required shunt revision (P<0.01). 62 of 64 (97%) LT infants and 36 of 62 (58%) HT infants had LPs (P<0.001). Reservoirs were inserted in 40 of 64 (62%) LT infants and 27 of 62 (43%) HT infants (P<0.05).

CONCLUSIONS

There was no significant difference in the primary composite outcome of VP shunt placement or death in infants with posthaemorrhagic ventricular dilatation who were treated at a lower versus a higher threshold for intervention. Infants treated at the lower threshold received more invasive procedures. Assessment of neurodevelopmental outcomes will provide further important information in assessing the risks and benefits of the two treatment approaches.

Preterm brain injury: Germinal matrix-intraventricular hemorrhage and post-hemorrhagic ventricular dilatation

Germinal matrix hemorrhage and intraventricular hemorrhages (GMH-IVH) remain a common and clinically significant problem in preterm infants, particularly extremely preterm infants. A large GMH-IVH is often complicated by posthemorrhagic ventricular dilation (PHVD) or parenchymal hemorrhagic infarction and is associated with an increased risk of adverse neurologic sequelae. The widespread use of cranial ultrasonography since the early 1980s has shown a gradual decrease in the incidence of GMH-IVH and has helped with the identification of antenatal and perinatal risk factors and timing of the lesion. The increased use of magnetic resonance imaging (MRI) has contributed to more detailed visualization of the site and extent of the GMH-IVH. In addition, MRI has contributed to the awareness of associated white matter changes as well as associated cerebellar hemorrhages. Although GMH-IVH and PHVD still cannot be prevented, cerebrospinal fluid drainage initiated in the early stage of PHVD development seems to be associated with a better neurodevelopmental outcome. Further studies are underway to improve treatment strategies for PHVD and to potentially prevent and repair GMH-IVH and PHVD and associated brain injury. This chapter discusses the pathogenesis, incidence, risk factors, and management, including preventive measures, of GHM-IVH and PHVD.

Relationships between Head Circumference Percentile, Lumbar Puncture Pressure, and Cerebrospinal Fluid Space in Young Children: Increased Cerebrospinal Space and Pressure May Result in Compensatory Enlargement of Head Circumference Only in the Infant Period

BACKGROUND

The aim of this study was to retrospectively evaluate and analyze the relationships between head circumference percentile (HCP), lumbar puncture pressure (LPP), and cerebrospinal fluid (CSF) space.

METHODS

The 88 patients were divided into 3 age groups (group 1, up to 12 months; group 2, 12-36 months; group 3, 36-72 months).

RESULTS

In group 1 (n = 40), there was a significant positive correlation of the HCP with the LPP (r =0.414, p =0.008), Evans ratio (r =0.365, p =0.021), and thickness of subdural hygroma (SDHG; r =0.403, p =0.010). Group 2 (n = 29) revealed a significant positive correlation between the LPP and the thickness of SDHG (r =0.459, p =0.012). Group 3 (n = 19) showed no significant correlation among these factors. Overall, age was related with SDHG thickness both in infants and toddlers, while HCP was related with LPP, Evans ratio, and SDHG thickness only in infants, and LPP was related with SDHG thickness only in toddlers.

CONCLUSION

We suggest that increased cerebrospinal space and pressure may result in compensatory enlargement of head circumference only in the infant period, and the SDHG thickness decreases with age during the infant and toddler phases.

Preterm neuroimaging and neurodevelopmental outcome: a focus on intraventricular hemorrhage, post-hemorrhagic hydrocephalus, and associated brain injury

Intraventricular hemorrhage in the setting of prematurity remains the most common cause of acquired hydrocephalus. Neonates with progressive post-hemorrhagic hydrocephalus are at risk for adverse neurodevelopmental outcomes. The goal of this review is to describe the distinct and often overlapping types of brain injury in the preterm neonate, with a focus on neonatal hydrocephalus, and to connect injury on imaging to neurodevelopmental outcome risk. Head ultrasound and magnetic resonance imaging findings are described separately. The current state of the literature is imprecise and we end the review with recommendations for future radiologic and neurodevelopmental research.

Quantitative 3-D head ultrasound measurements of ventricle volume to determine thresholds for preterm neonates requiring interventional therapies following posthemorrhagic ventricle dilatation

Dilatation of the cerebral ventricles is a common condition in preterm neonates with intraventricular hemorrhage. This posthemorrhagic ventricle dilatation (PHVD) can lead to lifelong neurological impairment through ischemic injury due to increased intracranial pressure, and without treatment can lead to death. Two-dimensional ultrasound (US) through the fontanelles of the patients is serially acquired to monitor the progression of PHVD. These images are used in conjunction with clinical experience and physical exams to determine when interventional therapies such as needle aspiration of the built up cerebrospinal fluid (ventricle tap, VT) might be indicated for a patient; however, quantitative measurements of the ventricles size are often not performed. We describe the potential utility of the quantitative three-dimensional (3-D) US measurements of ventricle volumes (VVs) in 38 preterm neonates to monitor and manage PHVD. Specifically, we determined 3-D US VV thresholds for patients who received VT in comparison to patients with PHVD who resolve without intervention. In addition, since many patients who have an initial VT will receive subsequent interventions, we determined which PHVD patients will receive additional VT after the initial one has been performed.

The use of clinical examination and cranial ultrasound in the diagnosis and management of post-hemorrhagic ventricular dilation in extremely premature infants

OBJECTIVES

The objective of this study is to describe clinical and ultrasound changes in a cohort of premature newborns with post-hemorrhagic ventricular dilation (PHVD), and to correlate these changes with outcome.

STUDY DESIGN

Premature newborns <29 weeks gestational age (GA) and ≤ 1,500 g birth weight with intraventricular hemorrhage were retrospectively reviewed. Clinical signs and cranial ultrasound (CUS) findings between time after birth and time before first cerebrospinal fluid temporizing intervention were compared with GA-equivalent newborns without interventions. White matter injury was assessed on brain magnetic resonance imaging.

RESULTS

Between 2011 and 2014, 64 newborns met inclusion criteria; 23% had PHVD. The growth rates of the ventricles on CUS and the head circumference (HC) were higher in newborns with PHVD (p < 0.01 and p = 0.04, respectively) and correlated inversely with white matter injury (p = 0.006 and p < 0.001, respectively).

CONCLUSION

Progression of PHVD in premature newborns as demonstrated by CUS and the HC correlated with outcome. Consistent measurement of these simple parameters will allow for much needed treatment comparisons, to define optimal protocols that decrease the risk of cerebral palsy in extremely preterm populations.

Early amplitude-integrated electroencephalography predicts brain injury and neurological outcome in very preterm infants

Early amplitude-integrated electroencephalography (aEEG) has been widely used in term infants with brain injury to predict neurodevelopmental outcomes; however, the prognostic value of early aEEG in preterm infants is unclear. We evaluated how well early aEEG could predict brain damage and long-term neurodevelopmental outcomes in very preterm infants compared with brain imaging assessments. We found that severe aEEG abnormalities (p=0.000) and aEEG total score<5 (p=0.006) within 72 h after birth were positively correlated with white-matter damage, but aEEG abnormalities were not associated with intracranial hemorrhage (p=0.186). Severe abnormalities in aEEG recordings, head ultrasound, and cranial magnetic resonance imaging (MRI) were all positively correlated with poor outcome at 18 months corrected age. The predictive power of poor outcomes of the aEEG and MRI combination was the same as the aEEG, MRI, and head ultrasound combination with a sensitivity of 52.4%, specificity of 96.2%, positive predictive value of 78.6%, and negative predictive value of 88.4%. These results indicate that severely abnormal aEEG recordings within 72 h after birth can predict white-matter damage and long-term poor outcomes in very preterm infants. Thus aEEG can be used as an early marker to monitor very preterm infants.