The preoperative incidence of raised intracranial pressure in nonsyndromic sagittal craniosynostosis is underestimated in the literature

Osseous Convexity at the Anterior Fontanelle: A Presentation of Metopic Fusion?

BACKGROUND

Craniosynostosis, or a premature fusion of 1 or more cranial vault sutures, results in characteristic head shape deformities. In previous reports, an osseous prominence at the anterior fontanelle has been suggestive of adjacent suture fusion and local elevation in intracranial pressure (ICP). This prominence has been termed the "volcano" sign, and has been described in the anterior fusion of the sagittal suture and serves as an indication for surgery.

METHODS

Two patients presented for head shape evaluation with mild metopic ridging and anterior fontanellar osseous convexities consistent with the volcano sign. Low-dose computed tomography imaging was performed in both patients due to concern for underlying craniosynostosis with elevated locoregional ICP.

RESULTS

In both patients, imaging was significant for a localized, superior forehead metopic fusion, as well as a bony, convex prominence at the site of the ossified anterior fontanelle. There were no other clinical or radiologic signs or symptoms to suggest elevated ICP. Surgery was not indicated in either patient.

CONCLUSIONS

Here the authors present 2 patients with osseous convexities at the site of the closed anterior fontanelle without signs or symptoms of elevated ICP, or classic signs of metopic synostosis. The authors hypothesize that this pattern may be due to a form of mechanically induced premature fusion of a normal metopic suture that is focused superiorly at the bregma, with minimal resultant restriction of overall skull growth. This is in contrast to metopic synostosis, which primarily has a sutural pathology and leads to characteristic findings of hypotelorism and trigonocephaly.

The value of three-dimensional photogrammetry in isolated sagittal synostosis: Impact of age and surgical technique on intracranial volume and cephalic index─a retrospective cohort study

PURPOSE

The aim of this study was to compare the outcome of intracranial volume (ICV) and cephalic index (CI) between two different techniques for surgical therapy of sagittal synostosis.

MATERIAL AND METHODS

Between 2011 and 2015, all patients scheduled for surgical therapy of sagittal synostosis were consecutively enrolled. All patients younger than 6 months underwent early extended strip craniectomy (ESC group), and patients older than 6 months underwent late modified pi-procedure (MPP group). To measure ICV and CI, data acquisition was performed via three-dimensional photogrammetry, 1 day before (T0) and between 10 and 12 weeks after surgery (T1). Results were compared with an age-matched reference group of healthy children. Perioperative parameters, as duration of surgery and the amount of blood loss of both surgical procedures were analyzed.

RESULTS

A total of 85 patients were enrolled. Of the patients, 48 underwent an extended strip craniotomy with parietal osteotomies and biparietal widening and 37 patients underwent a late modified pi-procedure. There was no significant difference between the ESC group and the MPP group regarding the efficacy of improving CI (p > 0.05). Both techniques were able to normalize CI and to improve head shape. ICV was normal compared to age-matched norm-groups with both techniques, pre- and postoperatively. However, duration of the surgical procedure and calculated blood loss were significantly lower in the ESC group (p < 0.05).

CONCLUSION

ESC and MPP were effective techniques to normalize cephalic index (CI) and improve head shape at their recommended time of surgery. Measurement of ICV and CI with 3D photogrammetry is a valid method to objectively evaluate patients before and after surgery without exposing pediatric patients to ionizing radiation.

Growth curves for intracranial volume in normal Asian children fortify management of craniosynostosis

BACKGROUND

Although the charting of normal intracranial volume (ICV) is fundamental for managing craniosynostosis, Asian norms in this regard are unknown. The purpose of this study was to establish a growth curve for ICVs in a large series of normal Asian children, providing reference values to guide corrective surgery.

METHODS

A total of 124 normal children (male, 63; female, 61) and 41 children diagnosed with craniosynostoses were analyzed. Patients aged 0-8 years presenting to the emergency room and subjected to computed tomography (CT) for head trauma served as the reference cohort. Axial CT head scan data were obtained from radiographic archives at Jichi Medical University. Imaging was done on a Siemens CT scanner (5-mm slice thickness), using a DICOM viewer to measure ICVs.

RESULTS

ICVs were plotted against age, and best-fit logarithmic curves for normal subjects were generated, without and with gender stratification. Male and female growth curves were similar in shape but diverged past the age of 1 year (male > female). ICVs of patients with craniosynostoses were plotted to male and female growth curves by disease subset, revealing the following: sagittal synostosis, near normal (or marginally larger); metopic synostosis, below normal; other non-syndromic synostoses (unilateral, bilateral, and lambdoidal) and Crouzon syndrome, near normal; Apert syndrome, above normal; and Pfeiffer syndrome, variable.

CONCLUSION

ICVs of early childhood were investigated in Asian subjects, creating growth curves that set criteria for timing, planning and goalsetting in surgical correction of craniosynostosis.

Changes in delta ADC reflect intracranial pressure changes in craniosynostosis

BACKGROUND

In patients with craniosynostosis, intracranial pressure (ICP) has been reported to increase even in the absence of overt symptoms. The early and non-invasive detection of intracranial hypertension is important for reducing the risk of abnormal brain development in pediatric patients.

PURPOSE

To assess whether the apparent diffusion coefficient (ADC) of white matter during the cardiac cycle (ΔADC) would change after surgery to relieve ICP in children with craniosynostosis.

MATERIAL AND METHODS

This prospective study included ten patients diagnosed with craniosynostosis and four normal controls. All ten patients underwent magnetic resonance (MR) examinations before and after surgical treatment. Single-shot diffusion MR imaging (MRI) triggered by an electrocardiogram was performed, with regions of interest (ROIs) placed on frontal white matter and basal ganglia.

RESULTS

In all ten patients, ΔADC values after surgery were higher than those before surgery. This difference was statistically significant (Wilcoxon signed-rank test, P = 0.005).

CONCLUSION

The change in ΔADC in the frontal white matter before and after surgery in patients with craniosynostosis indicates that it might reflect the change in ICP. Measurements of ΔADC could be a promising tool for non-invasive monitoring of ICP.

Telemetric Intracranial Pressure Monitoring in Syndromic Craniosynostosis

Syndromic and nonsyndromic craniosynostosis can be associated with raised intracranial pressure (ICP). After corrective surgery, raised ICP persists or reoccurs in a subgroup of patients. The standard procedure for monitoring ICP is insertion of a percutaneous intraparenchymal probe for a limited time, usually 24 to 48 hours. However, in selected patients repeated ICP measurements might be useful in the clinical setting, and a noninvasive method for achieving this would be desirable. The authors present the use of a telemetric ICP monitoring system implanted during cranial vault expansion in a child with syndromic craniosynostosis. This system, once implanted, allows for noninvasive transdermal ICP readings and might represent a promising alternative to conventional ICP monitoring devices in selected patients with craniofacial conditions.

Delayed Presentation of Isolated Sagittal Synostosis With Raised Intracranial Pressure and Secondary Chiari Malformation With Cervical Syringomyelia

Sagittal craniosynostosis (SC) is the most common type of premature suture fusion presenting in approximately 1 in every 5000 births with a 3:1 male:female ratio. The most common indication for surgery is the improvement of the cosmetic appearance of the skull, since a cranial deformation may have a significant psychosocial impact on affected patients. Relief from raised intracranial pressure is a further indication for surgery, although an increased intracranial pressure (ICP) can be demonstrated only in a minority of affected children at diagnosis. It is even more rare to have Chiari malformations (CMs) secondary to ICP in an isolated SC, as shown in a study by Strahle et al (Neurosurg Focus 2011;31:E2), demonstrating only 5 (3%) of the 183 with isolated sagittal synostosis having a CM. The authors present the rare case of a 4-year-old boy presenting late with raised intracranial pressure (40 mm Hg) and his management with 1 stage vault expansion and decompression of CM.

Acute pressure changes in the brain are correlated with MR elastography stiffness measurements: initial feasibility in an in vivo large animal model

PURPOSE

The homeostasis of intracranial pressure (ICP) is of paramount importance for maintaining normal brain function. A noninvasive technique capable of making direct measurements of ICP currently does not exist. MR elastography (MRE) is capable of noninvasively measuring brain tissue stiffness in vivo, and may act as a surrogate to measure ICP. The objective of this study was to investigate the impact of changing ICP on brain stiffness using MRE in a swine model.

METHODS

Baseline MRE measurements were obtained, and then catheters were surgically placed into the left and right lateral ventricles of three animals. ICP was systematically increased over the range of 0 to 55 millimeters mercury (mmHg), and stiffness measurements were made using brain MRE at vibration frequencies of 60 hertz (Hz), 90 Hz, 120 Hz, and 150 Hz.

RESULTS

A significant linear correlation between stiffness and ICP in the cross-subject comparison was observed for all tested vibrational frequencies (P ≤ 0.01). The 120 Hz (0.030 ± 0.004 kilopascal (kPa)/mmHg, P < 0.0001) and 150 Hz (0.031 ± 0.008 kPa/mmHg, P = 0.01) vibrational frequencies had nearly identical slopes, which were approximately two- to three-fold higher than the 90 Hz (0.017 ± 0.002 kPa/mmHg, P < 0.0001) and 60 Hz (0.009 ± 0.002 kPa/mmHg, P = 0.001) slopes, respectively.

CONCLUSION

In this study, MRE demonstrated the potential for noninvasive measurement of changes in ICP. Magn Reson Med 79:1043-1051, 2018. © 2017 The Authors Magnetic Resonance in Medicine published by Wiley Periodicals, Inc. on behalf of International Society for Magnetic Resonance in Medicine. This is an open access article under the terms of the Creative Commons Attribution-NonCommercial-NoDerivs License, which permits use and distribution in any medium, provided the original work is properly cited, the use is non-commercial and no modifications or adaptations are made.

Nonsyndromic Craniosynostosis and Deformational Head Shape Disorders

This article provides an overview of etiology, epidemiology, pathology, diagnosis, and treatment of nonsyndromic craniosynostosis, including sagittal, metopic, coronal, lambdoid, and complex synostosis. Detailed discussion is presented regarding indications for surgical intervention and management options, including frontoorbital advancement, cranial vault reconstruction, endoscopic strip craniectomy, spring-assisted strip craniectomy, and cranial vault distraction osteogenesis. Deformational plagiocephaly is also presented with treatment options including repositioning, physical therapy, and helmet therapy.

Evaluation of Optical Coherence Tomography to Detect Elevated Intracranial Pressure in Children

Importance

Detecting elevated intracranial pressure in children with subacute conditions, such as craniosynostosis or tumor, may enable timely intervention and prevent neurocognitive impairment, but conventional techniques are invasive and often equivocal. Elevated intracranial pressure leads to structural changes in the peripapillary retina. Spectral-domain (SD) optical coherence tomography (OCT) can noninvasively quantify retinal layers to a micron-level resolution.

Objective

To evaluate whether retinal measurements from OCT can serve as an effective surrogate for invasive intracranial pressure measurement.

Design, Setting, and Participants

This cross-sectional study included patients undergoing procedures at the Children's Hospital of Philadelphia from September 2014 to June 2015. Three groups of patients (n = 79) were prospectively enrolled from the Craniofacial Surgery clinic including patients with craniosynostosis (n = 40). The positive control cohort consisted of patients with hydrocephalus and suspected intracranial hypertension (n = 5), and the negative control cohort consisted of otherwise healthy patients undergoing a minor procedure (n = 34).

Main Outcomes and Measures

Spectral-domain OCT was performed preoperatively in all cohorts. Children with cranial pathology, but not negative control patients, underwent direct intraoperative intracranial pressure measurement. The primary outcome was the association between peripapillary retinal OCT parameters and directly measured elevated intracranial pressure.

Results

The mean (SD) age was 34.6 (45.2) months in the craniosynostosis cohort (33% female), 48.9 (83.8) months in the hydrocephalus and suspected intracranial hypertension cohort (60% female), and 59.7 (64.4) months in the healthy cohort (47% female). Intracranial pressure correlated with maximal retinal nerve fiber layer thickness (r = 0.60, P ≤ .001), maximal retinal thickness (r = 0.53, P ≤ .001), and maximal anterior retinal projection (r = 0.53, P = .003). Using cut points derived from the negative control patients, OCT parameters yielded 89% sensitivity (95% CI, 69%-97%) and 62% specificity (95% CI, 41%-79%) for detecting elevated intracranial pressure. The SD-OCT measures had high intereye agreement (intraclass correlation, 0.83-0.93) and high intragrader and intergrader agreement (intraclass correlation ≥0.94). Conventional clinical signs had low sensitivity (11%-42%) for detecting intracranial hypertension.

Conclusions and Relevance

Noninvasive quantitative measures of the peripapillary retinal structure by SD-OCT were correlated with invasively measured intracranial pressure. Optical coherence tomographic parameters showed promise as surrogate, noninvasive measures of intracranial pressure, outperforming other conventional clinical measures. Spectral-domain OCT of the peripapillary region has the potential to advance current treatment paradigms for elevated intracranial pressure in children.

Noninvasive epicutaneous transfontanelle intracranial pressure monitoring in children under the age of 1 year: a novel technique

Monitoring of intracranial pressure (ICP) may be indicated in children with traumatic brain injury, premature intraventricular hemorrhage, or hydrocephalus. The standard technique is either a direct measurement with invasive intracranial insertion of ICP probes or indirect noninvasive assessment using transfontanelle ultrasonography to measure blood flow. The authors have developed a new technique that allows noninvasive epicutaneous transfontanelle ICP measurement with standard ICP probes. They compared the ICP measurements obtained using the same type of standard probe used in 2 different ways in 5 infants (age < 1 year) undergoing surgery for craniosynostosis. The first ICP probe was implanted epidurally (providing control measurements) and the second probe was fixed epicutaneously on the skin over the reopened frontal fontanelle. ICP values were measured hourly for the first 24 hours after surgery and the values obtained with the 2 methods were compared using Bland-Altman 2-methods analysis. A total of 110 pairs of measurements were assessed. There was no significant difference between the ICPs measured using the epicutaneous transfontanelle method (mean 13.10 mm Hg, SEM 6.68 mm Hg) and the epidural measurements (mean 12.46 mm Hg, SEM 6.45 mm Hg; p = 0.4643). The results of this analysis indicate that epicutaneous transfontanelle measurement of ICP is a reliable method that allows noninvasive ICP monitoring in children under the age of 1 year. Such noninvasive ICP monitoring could be implemented in the therapy of children with traumatic brain injury or intraventricular hemorrhage or for screening children with elevated ICP without invasive intracranial implantation of ICP probes.

Effect of molding helmets on intracranial pressure and head shape in nonsurgically treated sagittal craniosynostosis patients

OBJECTIVE Cranial vault expansion is performed in pediatric patients with craniosynostosis to improve head shape. Another argument for performing total cranial vault reconstruction is the potential reduction in the harmful effects of elevated intracranial pressure (ICP) that are associated with craniosynostosis. Alternatively, molding helmets have been shown to improve the cranial index (CI) in patients with sagittal synostosis without surgery. However, it is unknown if the use of molding helmets without surgery contributes to adverse changes in ICP. The effect of molding helmets on ICP and CI in patients with sagittal synostosis was investigated. METHODS A prospective cohort study of 24 pediatric patients with sagittal synostosis who planned to undergo total cranial reconstruction was performed from 2011 to 2014 at the Children's Hospital of Michigan. A preoperative molding helmet was used in 13 patients, and no molding helmet was used in 11 patients. End-tidal carbon dioxide, patient positioning, level of sedation, type of anesthetic, and the monitoring site at the time of intraoperative recording were regulated and standardized to establish the accuracy of the ICP readings. CI and head circumference were monitored for each patient. RESULTS The mean duration of the preoperative use of the molding helmet was 17 weeks (range 7-37 weeks). Under controlled settings, the average intraoperative ICP was 7.2 mm Hg (range 2-18 mm Hg) for patients treated with a preoperative molding helmet and 9.5 mm Hg (range 2-22 mm Hg) for patients with no preoperative molding helmet. ICP was not significantly different between the 2 groups, suggesting that the use of a molding helmet in this population is safe. The average CI at the time of helmet placement was 0.70 (range 0.67-0.73), and this improved to an average of 0.74 (range 0.69-0.79) after using the molding helmet for a mean of 17 weeks. CONCLUSIONS ICPs were not significantly different with the use of a preoperative molding helmet, refuting the prevailing thought that molding helmets would be detrimental in children who have craniosynostosis. The use of molding helmet in this population of patients improves head shape and does not adversely affect ICP.

Telemetric intracranial pressure monitoring: a noninvasive method to follow up children with complex craniosynostoses. A case report

INTRODUCTION

There are no reliable noninvasive methods of monitoring ICP. Most assessments are made by indirect measures and are difficult to follow over time. Invasive studies can be used but up until now have required in-hospital transcutaneous measurements. Accurate ICP recordings over longer periods of time can be very valuable in timing different surgical procedures in syndromal cases. This case shows that telemetric ICP monitoring can be used for long-term follow-up in patients that may need repeated surgeries related to their craniosynostosis condition.

CASE REPORT

In this report, the telemetric ICP probe (Raumedic Neurovent-P-tel) was implanted before surgery and was used for repeated "noninvasive" ICP recordings pre- and postoperatively in a patient with craniosynostosis. The patient was an eight-year-old girl with pansynostosis with only the right lambdoid suture open. A telemetric ICP probe was implanted the day before cranial vault remodeling and the ICP was monitored pre- and postoperatively. The ICP was above 15 mmHg 72.2 % of the monitoring time before surgery, and the amplitude of the curve was greater than normal suggesting impaired compliance. Direct postoperative ICP was normal, and the amplitude was lower. The ICP was then monitored both in out-patient clinic and in four longer hospital stays. Both the values and the curves were analyzed, and the time with ICP above 15 mmHg decreased over time, and the waveform amplitude of the curves improved.

CONCLUSION

This "noninvasive" way of recording ICP is a feasible and helpful tool in decision-making and intervening in patients with craniosynostosis.

Lumbar Puncture Pressures During Childhood in 262 Children with Craniosynostosis

OBJECTIVE

The aim of this study was to analyze age-dependent lumbar puncture pressures (LPPs) measured in 262 children with craniosynostosis to provide information that assists in determining surgery.

METHODS

From 1 July 2005 to 30 June 2014, 262 children with craniosynostosis diagnosed at the Department of Neurosurgery, Ajou University Hospital, underwent LPP measurement. These children were compared with respect to age, gender, birth weight, head circumference at the time of birth, gestational age, LPP, and developmental assessments.

RESULTS

Changes in LPP in children with craniosynostosis according to age were y = -0.0007x(2) + 0.1327x + 21.678 in all patients overall, y = -0.0003x(2) + 0.1166x + 21.466 in children with single-suture craniosynostosis, and y = -0.002x(2) + 0.248x + 22.55 in patients with multiple and syndromic craniosynostosis, indicating a steady and slow increase from birth until the age of 4 years. Also, 59.9% of the 262 children had LPP greater than 20 cm H2O, but when the LPP cutoff level was adjusted for age, this proportion was 99.2%; the new criterion after the adjusted LPP cutoff level showed that for those with increased LPP, the proportion was 63.4%.

CONCLUSIONS

We suggest that LPP increases slowly with age in children with craniosynostosis, increased LPP rates in children with craniosynostosis were higher than previously expected, and the new cutoff level criterion that adjusts for age may be more helpful than a fixed cutoff level for all ages.

Language, learning, and memory in children with and without single-suture craniosynostosis

OBJECTIVE The language and memory functions of children with and without single-suture craniosynostosis (SSC) were compared at school age (mean 7.45 years, standard deviation [SD] 0.54 years). The children in this cohort were originally recruited in infancy and prior to cranial surgery for those with SSC. METHODS Individual evaluations of 179 school-aged children with SSC and 183 controls were conducted (70% of the original cohort) using standardized measures of language, learning, and memory. Parents participated in an interview about specialized education interventions and school progress. Parents and teachers completed questionnaires about language development. RESULTS Children with SSC (cases) obtained lower scores than controls on all measures. The adjusted differences in language, learning, and memory scores were modest, with SD ranging from 0.0 to -0.4 (p values ranged from 0.001 to 0.99). Censored normal regression was used to account for intervention services received prior to the school-age evaluation; this increased case-control differences (SD range 0.1 to -0.5, p value range 0.001 to 0.50). Mean scores for cases in each SSC diagnostic group were lower than those for controls, with the greatest differences observed among children with unilateral coronal craniosynostosis. CONCLUSIONS Children with SSC continue to show poorer performance than controls on language, learning, and memory tasks at early elementary school age, even when controlling for known confounders, although mean differences are small. Multidisciplinary care, including direct psychological assessment, for children with SSC should extend through school age with a specific focus on language and conceptual learning, as these are areas of potential risk. Future research is needed to investigate language, memory, and learning for this population during the middle to high school years.

Intracranial volume (ICV) in isolated sagittal craniosynostosis measured by 3D photocephalometry: A new perspective on a controversial issue

BACKGROUND

There are still controversies regarding the intracranial volumes in patients with isolated sagittal craniosynostosis compared to a healthy population. This study aimed to compare the intracranial volume of children with sagittal synostosis and scaphocephaly to an age- and gender-matched control cohort using three-dimensional (3D) photogrammetry.

METHODS

62 boys and nine girls with sagittal craniosynostosis were included in this study. The intracranial volume was measured at the first clinical presentation. However, 3D photogrammetry was performed at children not younger than 3 months. The 3D photogrammetric data of 547 healthy boys and 287 healthy girls between the ages of 3-10 month was analyzed to establish an age- and gender-matched control group.

RESULTS

Male patients with sagittal synostosis showed a significantly reduced intracranial volume compared to the reference group. For female patients, the intracranial volume was slightly lower compared to the norm group, but not significantly.

CONCLUSIONS

Male children with sagittal synostosis showed significantly decreased intracranial volume between the age of 3 and 10 months compared to an age- and gender-matched control group. Female patients in the same age group presented a lower intracranial volume compared to the norm group. Measuring intracranial volume using 3D photogrammetry is a comparable and valuable alternative to CT scans that leads to a significant reduction of radiation exposure to the growing brain.

Craniosynostosis

Craniosynostosis is the premature fusion of one or more of the cranial sutures. About 8% of the patients have familial or syndromic forms of synostosis, and in the remainder it occurs as a spontaneous isolated defect. Familial craniosynostosis syndromes are typically transmitted as an autosomal dominant trait resulting in disruption of the fibroblast growth factor receptor pathway. Familiarity with the characteristic head shapes resulting from craniosynostosis allows bedside diagnosis and differentiation from positional plagiocephaly. Because of the risks associated with untreated craniosynostosis, surgical treatment is usually undertaken soon after diagnosis. Current surgical methods include open calvarial reconstruction, minimally invasive strip craniectomy with use of postoperative molding helmet, minimally invasive strip craniectomy with spring implantation, and cranial distraction. Early referral to a pediatric craniofacial center allows all treatment options to be explored.

Mechanics of the brain: perspectives, challenges, and opportunities

The human brain is the continuous subject of extensive investigation aimed at understanding its behavior and function. Despite a clear evidence that mechanical factors play an important role in regulating brain activity, current research efforts focus mainly on the biochemical or electrophysiological activity of the brain. Here, we show that classical mechanical concepts including deformations, stretch, strain, strain rate, pressure, and stress play a crucial role in modulating both brain form and brain function. This opinion piece synthesizes expertise in applied mathematics, solid and fluid mechanics, biomechanics, experimentation, material sciences, neuropathology, and neurosurgery to address today’s open questions at the forefront of neuromechanics. We critically review the current literature and discuss challenges related to neurodevelopment, cerebral edema, lissencephaly, polymicrogyria, hydrocephaly, craniectomy, spinal cord injury, tumor growth, traumatic brain injury, and shaken baby syndrome. The multi-disciplinary analysis of these various phenomena and pathologies presents new opportunities and suggests that mechanical modeling is a central tool to bridge the scales by synthesizing information from the molecular via the cellular and tissue all the way to the organ level.