Non-invasive assessment of ICP in children: advances in ultrasound-based techniques.

The assessment of intracranial pressure (ICP) in children with neurological disease remains a cornerstone in their routine management. The quest for a reliable, reproducible and radiation-free non-invasive technique for assessing ICP in children remains somewhat of a holy grail for neurosurgery. This work assesses some of the recent advances in ultrasound-based techniques, addressing both novel processes and modifications aimed at improving the accuracy of existing techniques.

Hydatid disease (Echinococcus) of the central nervous system.

Hydatid disease of the central nervous system is rare and comprises about 2-3% of all the hydatid cyst cases reported in the world. Spinal hydatid is still rare. It is endemic in sheep and cattle-raising regions, seen mainly in Mediterranean countries including Turkey and Syria. Pediatric neurosurgeons in nonendemic countries face a challenge when they are encountered with hydatid cyst of the central nervous system due to lack of awareness and diagnostic dilemmas. It is also a mammoth economic problem in developing countries due to improper hygiene and lack of dedicated veterinary practice. The clinical features are largely nonspecific. However, with the advent of MR imaging, the diagnostic accuracy has increased. Intact removal of the cyst without causing any spillage is the goal and key to cure. In this manuscript, the current literature on hydatid cyst of the brain and spine is reviewed to understand the epidemiological, diagnostic accuracy and advances in therapeutics. A heightened clinical suspicion about hydatid disease, role of MR imaging and improving surgical strategies is discussed. A nationwide prevention of the disease is the ultimate goal.

Infections in the immunocompromised child.

Prevention and management of opportunistic infections in children is particularly relevant in an era demonstrating an increased prevalence of immunocompromising conditions. The presence of an unusual organism which results in serious infection in a child should therefore always raise the consideration of immune compromise. The more common opportunistic infections have become easier to recognize in recent times due to improved awareness and more refined diagnostic testing. Targeted treatment is usually followed by long-term prophylactic medication. The impact of these conditions on patient outcome is of clear significance and certainly warrants further discussion.

The relationship between transorbital ultrasound measurement of the optic nerve sheath diameter (ONSD) and invasively measured ICP in children. : Part II: age-related ONSD cut-off values and patency of the anterior fontanelle.

PURPOSE: To analyse the diagnostic accuracy of age-related optic nerve sheath diameter (ONSD) cut-off values in children for detecting raised intracranial pressure (ICP) and to assess the benefit of using patency of the anterior fontanelle in describing a different set of cut-off values. METHODS: The ONSD measurement was performed prior to invasive ICP measurement in children under general anesthesia. The diagnostic accuracy of the ONSD measurement was compared to ICP at thresholds of 20, 15, 10, and 5 mmHg. This was further analysed in children above and below the age of 1 year, with a subgroup analysis of age at 4 years, and assessment of the anterior fontanelle (AF) as a reliable physiological marker in part II of this study. RESULTS: Data from 174 children were analysed. In children ≤1 year old, the ONSD measurement with the best diagnostic accuracy for detecting ICP ≥ 20 mmHg was 5.16 mm, compared to 5.75 mm in children >1 year old (p < 0.001). In addition, patency of the anterior fontanelle (AF) was found to be a useful clinical marker for defining different ONSD cut-off values at ICP thresholds of 20, 15, 10 and 5 mmHg. CONCLUSION: Transorbital ultrasound measurement of the ONSD is a reliable non-invasive marker of ICP particularly at higher thresholds of 20 and 15 mmHg. Patency of the AF is a useful clinical marker for defining different ONSD cut-off values in children.

The relationship between transorbital ultrasound measurement of the optic nerve sheath diameter (ONSD) and invasively measured ICP in children : Part I: repeatability, observer variability and general analysis.

PURPOSE: The aim of this study was to investigate the relationship between optic nerve sheath diameter (ONSD) measurement and invasively measured intracranial pressure (ICP) in children. METHODS: ONSD measurement was performed prior to invasive measurement of ICP. The mean binocular ONSD measurement was compared to the ICP reading. Physiological variables including systolic blood pressure (SBP), diastolic blood pressure (DBP), mean arterial pressure (MAP), pulse rate, temperature, respiratory rate and end tidal carbon dioxide (ETCO2) level were recorded at the time of ONSD measurement. Diagnostic accuracy analysis was performed at various ICP thresholds and  repeatability, intra- and inter-observer variability, correlation between measurements in different imaging planes as well the relationship over the entire patient cohort were examined in part I of this study. RESULTS: Data from 174 patients were analysed. Repeatability and intra-observer variability were excellent (α = 0.97-0.99). Testing for inter-observer variability revealed good correlation (r = 0.89, p < 0.001). Imaging in the sagittal plane demonstrated a slightly better correlation with ICP (r = 0.66, p < 0.001). The ONSD measurement with the best diagnostic accuracy for detecting an ICP ≥ 20 mmHg over the entire patient cohort was 5.5 mm, sensitivity 93.2 %, specificity 74 % and odds ratio (OR) of 39.3. CONCLUSION: Transorbital ultrasound measurement of the OSND is a reliable and reproducible technique, demonstrating a good relationship with ICP and high diagnostic accuracy for detecting raised ICP.

Non-invasive intracranial pressure assessment.

Assessing intracranial pressure (ICP) remains a cornerstone in neurosurgical care. Invasive techniques for monitoring ICP remain the gold standard. The need for a reliable, safe and reproducible technique to non-invasively assess ICP in the context of early screening and in the neurocritical care environment is obvious. Numerous techniques have been described with several novel advances. While none of the currently available techniques appear independently accurate enough to quantify raised ICP, there is some promising work being undertaken.

Change in optic nerve sheath diameter as a radiological marker of outcome from endoscopic third ventriculostomy in children.

PURPOSE: The purpose of this study was to investigate the value of the change in optic nerve sheath diameter (ONSD) as a radiological marker of endoscopic third ventriculostomy (ETV) outcome in children. METHODS: Magnetic resonance imaging (MRI) scans of patients on whom ETVs were performed between the periods of January 2009 and June 2013 were reviewed. ONSD measurements on pre- and post-operative images were performed by two blinded observers, and the relationship between the change in these measurements and outcome from ETV were investigated. These findings were then also compared to conventional imaging features associated with ETV outcome. RESULTS: MRI scans of 24 patients were adequate to measure the ONSD pre- and post-operatively. In patients with successful ETV (n = 19), the mean change in ONSD was 0.73 mm and in patients with a failed ETV (n = 5), the mean change in ONSD was 0.18 mm (p = 0.0007). A change in ONSD of 7.5 % of the initial measurement demonstrated a sensitivity of 92.9 % and a sensitivity of 85.7 % for ETV outcome (area under the receiver operating characteristic curve (AUROC) = 0.96). CONCLUSION: Change in ONSD is a useful radiological marker of ETV outcome and may be used in combination with conventional radiological parameters to aid decision-making in this difficult group of patients.

The frequency of cerebral ischemia/hypoxia in pediatric severe traumatic brain injury.

INTRODUCTION: The frequency of adverse events, such as cerebral ischemia, following traumatic brain injury (TBI) is often debated. Point-in-time monitoring modalities provide important information, but have limited temporal resolution. PURPOSE: This study examines the frequency of an adverse event as a point prevalence at 24 and 72 h post-injury, compared with the cumulative burden measured as a frequency of the event over the full duration of monitoring. METHODS: Reduced brain tissue oxygenation (PbtO(2) < 10 mmHg) was the adverse event chosen for examination. Data from 100 consecutive children with severe TBI who received PbtO(2) monitoring were retrospectively examined, with data from 87 children found suitable for analysis. Hourly recordings were used to identify episodes of PbtO(2) less than 10 mmHg, at 24 and 72 h post-injury, and for the full duration of monitoring. RESULTS: Reduced PbtO(2) was more common early than late after injury. The point prevalence of reduced PbtO(2) at the selected time points was relatively low (10 % of patients at 24 h and no patients at the 72-h mark post-injury). The cumulative burden of these events over the full duration of monitoring was relatively high: 50 % of patients had episodes of PbtO(2) less than 10 mmHg and 88 % had PbtO(2) less than 20 mmHg. CONCLUSION: Point-in-time monitoring in a dynamic condition like TBI may underestimate the overall frequency of adverse events, like reduced PbtO(2), particularly when compared with continuous monitoring, which also has limitations, but provides a dynamic assessment over a longer time period.

Intracranial pressure monitoring for traumatic brain injury in the modern era.

INTRODUCTION: Intracranial pressure (ICP) has become a cornerstone of care in adult and pediatric patients with traumatic brain injury (TBI). DISCUSSION: Despite the fact that continuous monitoring of ICP in TBI was described almost 60 years ago, there are no randomized trials confirming the benefit of ICP monitoring and treatment in TBI. There is, however, a large body of clinical evidence showing that ICP monitoring influences treatment and leads to better outcomes if part of protocol-driven therapy. However, treatment of ICP has adverse effects, and there are several questions about ICP management that have yet to be definitively answered, particularly in pediatric TBI. This review examines the history and evolution of ICP monitoring, pathophysiological concepts that influence ICP interpretation, ongoing controversies, and the place of ICP monitoring in modern neurocritical care.