Anomalous venous collaterals in Apert and Crouzon syndromes and their relationship to ventricle size and increased intracranial pressure.

OBJECTIVE: The exact association between the frequently present anomalous intracranial venous vasculature, emissary collaterals, ventriculomegaly, and increased intracranial pressure (ICP) in children with Apert and Crouzon syndromes remains an enigma. This study aimed to evaluate the association between the aberrant venous system and ventricle size and increased ICP, and to assess the development of the venous structures over time. METHODS: This retrospective cohort study included all patients with Apert or Crouzon syndrome with available CT venography (CTV) scans of the brain. Anomalous venous vasculature was assessed by the total collateral score (TCS), which scored 9 intra- and extracranial venous structures (TCS range 0-16). Ventricle size (fronto-occipital horn ratio [FOHR]) was measured on the same scan. The presence of increased ICP, a shunt, tonsillar herniation, and head circumference were extracted from electronic patient records and were used as secondary covariates. Subsequent CTV scans were scored when available. RESULTS: Ninety patients were included in this study. The mean TCS was 7.5 ± 2.5, and was comparable for patients with Apert and Crouzon syndromes (mean 8.0 and 7.3, respectively). The presence of an extra abnormal venous structure was associated with an increase of the FOHR of 3.2% (p < 0.01). After dividing the venous structures into intra- and extracranial, a similar association between both and the FOHR was found (4.1% and 2.3%, respectively; p < 0.01). The TCS was similar for patients with normal and increased ICP at the time of the scan. Sixteen patients had dual CTV scans. The median time between both scans was 3.2 years. The presence of collaterals remained stable over time (median ΔTCS = 0.3). Seven patients with functioning shunts also maintained high TCSs (median TCS = 9). CONCLUSIONS: In patients with Apert and Crouzon syndromes, a close relationship between venous collaterals and ventricle size was observed, in which a more extensive aberrant venous drainage pattern, both intra- and extracranial, was associated with larger ventricles. Preliminary longitudinal data suggested that the presence of venous collaterals remained constant over time despite effective treatment of increased ICP, indicating reliance on these collaterals even in cases of normal ICP. The authors hypothesize that this dependence on collateral drainage is the result of their aberrant internal venous anatomy and predisposes individuals to increased ICP.

Forehead shape analysis following surgical and conservative treatment in metopic synostosis: a 3D photogrammetry analysis.

BACKGROUND: The aim of this study is to describe and compare head shape in surgically and conservatively treated patients using 3D photogrammetry. METHODS: A retrospective review (2017-2020) of consecutive patients with isolated metopic synostosis based on 3D photogrammetry was conducted at the age of 4 years old. Images were aligned using a healthy age-matched template, and mean head shapes were reconstructed to evaluate shape development. A comparative sub-analysis based on phenotype was performed between patients that have been treated surgically and conservatively. RESULTS: 44 patients with isolated metopic synostosis were included: 22 received conservative treatment and 22 underwent fronto-orbital advancement. At 4 years of age the surgical group showed retrusion of the complete frontal area, while the conservative group showed a slight frontal prominence. Both groups showed temporal depression with respect to the control. In the sub-analysis, a similar degree of temporal depression was observed between surgical and conservative treatment. Head shape patterns showed considerable similarity across all severity phenotypes. CONCLUSION: This study shows a deviation in forehead shape from normal controls in patients with metopic synostosis following both surgical and conservative treatment by the age of 4 years. Comparison between surgical and conservative treatment shows a similar degree of temporal depression, a slight prominence in the center of the forehead in the conservative group, and retrusion of the entire frontal area in the surgical group. This observed difference is of considerable similarity across all severity types. LEVEL OF EVIDENCE THERAPEUTIC: III.

Quantifying dysmorphologies of the neurocranium using artificial neural networks.

BACKGROUND: Craniosynostosis, a congenital condition characterized by the premature fusion of cranial sutures, necessitates objective methods for evaluating cranial morphology to enhance patient treatment. Current subjective assessments often lead to inconsistent outcomes. This study introduces a novel, quantitative approach to classify craniosynostosis and measure its severity. METHODS: An artificial neural network was trained to classify normocephalic, trigonocephalic, and scaphocephalic head shapes based on a publicly available dataset of synthetic 3D head models. Each 3D model was converted into a low-dimensional shape representation based on the distribution of normal vectors, which served as the input for the neural network, ensuring complete patient anonymity and invariance to geometric size and orientation. Explainable AI methods were utilized to highlight significant features when making predictions. Additionally, the Feature Prominence (FP) score was introduced, a novel metric that captures the prominence of distinct shape characteristics associated with a given class. Its relationship with clinical severity scores was examined using the Spearman Rank Correlation Coefficient. RESULTS: The final model achieved excellent test accuracy in classifying the different cranial shapes from their low-dimensional representation. Attention maps indicated that the network's attention was predominantly directed toward the parietal and temporal regions, as well as toward the region signifying vertex depression in scaphocephaly. In trigonocephaly, features around the temples were most pronounced. The FP score showed a strong positive monotonic relationship with clinical severity scores in both scaphocephalic (ρ = 0.83, p < 0.001) and trigonocephalic (ρ = 0.64, p < 0.001) models. Visual assessments further confirmed that as FP values rose, phenotypic severity became increasingly evident. CONCLUSION: This study presents an innovative and accessible AI-based method for quantifying cranial shape that mitigates the need for adjustments due to age-specific size variations or differences in the spatial orientation of the 3D images, while ensuring complete patient privacy. The proposed FP score strongly correlates with clinical severity scores and has the potential to aid in clinical decision-making and facilitate multi-center collaborations. Future work will focus on validating the model with larger patient datasets and exploring the potential of the FP score for broader applications. The publicly available source code facilitates easy implementation, aiming to advance craniofacial care and research.

Child-Patient Perspective on Results After Correction of Sagittal Synostosis and the Difference Between Child-Patient and Parent's Perspectives.

OBJECTIVE: This study assesses the level of child-patient satisfaction with the surgical result after scaphocephaly correction and the difference between child-patient and parents' perspectives. METHODS: A questionnaire was sent out to children between 6 and 18 years old with isolated sagittal synostosis, who had undergone either a frontobiparietal remodeling or extended strip craniotomy, and separately to their parents. RESULTS: The questionnaire was completed by 96 patients, 81.2% of the patients considered their head to be similar or slightly different from others. Despite the majority being satisfied with the outcome, 33% would change the shape of their head if they could. Patients who underwent extended strip craniotomy wanted to change the back of their head more often ( P = 0.002), whereas patients who underwent frontobiparietal remodeling wanted to change their forehead ( P = 0.005). The patients' own perspective on head shape was independent of the cephalic index (CI). However, patients with a relatively narrow CI received more remarks from others about their heads ( P = 0.038). Parent and child agreement was 49.7% on average. Differences between child-patients and parents were found in reporting adaptive behavior. CONCLUSION: The majority of patients were satisfied with the outcome of their intervention. The child's perspective seems to be a valuable addition to evaluate sagittal synostosis surgery as it is independent of the CI and differentiates between different surgical techniques. In addition, the patient's perspective is comparable to the parent's perspective, but gives more details on adaptive behavior.

3D Analysis of the Cranial and Facial Shape in Craniosynostosis Patients: A Systematic Review.

With increasing interest in 3D photogrammetry, diverse methods have been developed for craniofacial shape analysis in craniosynostosis patients. This review provides an overview of these methods and offers recommendations for future studies. A systematic literature search was used to identify publications on 3D photogrammetry analyses in craniosynostosis patients until August 2023. Inclusion criteria were original research reporting on 3D photogrammetry analyses in patients with craniosynostosis and written in English. Sixty-three publications that had reproducible methods for measuring cranial, forehead, or facial shape were included in the systematic review. Cranial shape changes were commonly assessed using heat maps and curvature analyses. Publications assessing the forehead utilized volumetric measurements, angles, ratios, and mirroring techniques. Mirroring techniques were frequently used to determine facial asymmetry. Although 3D photogrammetry shows promise, methods vary widely between standardized and less conventional measurements. A standardized protocol for the selection and documentation of landmarks, planes, and measurements across the cranium, forehead, and face is essential for consistent clinical and research applications.

A European multicenter outcome study on the different perioperative airway management policies following midface surgery in syndromic craniosynostosis: a proposal for a Standard Operating Procedure.

BACKGROUND: Perioperative airway management following midface advancements in children with Apert and Crouzon/Pfeiffer syndrome can be challenging, and protocols often differ. This study examined airway management following midface advancements and postoperative respiratory complications. METHODS: A multicenter, retrospective cohort study was performed to obtain information about the timing of extubation, perioperative airway management, and respiratory complications after monobloc / le Fort III procedures. RESULTS: Ultimately, 275 patients (129 monobloc and 146 Le Fort III) were included; 62 received immediate extubation and 162 delayed extubation; 42 had long-term tracheostomies and nine perioperative short-term tracheostomies. Short-term tracheostomies were in most centers reserved for selected cases. Patients with delayed extubation remained intubated for three days (IQR 2 - 5). The rate of no or only oxygen support after extubation was comparable between patients with immediate and delayed extubation, 58/62 (94%) and 137/162 (85%) patients, respectively. However, patients with immediate extubation developed less postoperative pneumonia than those with delayed, 0/62 (0%) versus 24/161 (15%) (P = 0.001), respectively. Immediate extubation also appeared safe in moderate/severe OSA since 19/20 (95%) required either no or only oxygen support after extubation. The odds of developing intubation-related complications increased by 21% with every extra day of intubation. CONCLUSIONS: Immediate extubation following midface advancements was found to be a safe option, as it was not associated with respiratory insufficiency but did lead to fewer complications. Immediate extubation should be considered routine management in patients with no/mild OSA and should be the aim in moderate/severe OSA after careful assessment.

Health-related Quality of Life in Children and Adolescents With Sagittal Synostosis.

BACKGROUND: This study evaluated the health-related quality of life (HR-QoL) in patients with sagittal synostosis (SS), and the influence of frequent headaches and surgical techniques on the HR-QoL. METHOD: Patients with SS aged 8 to 18 years were invited to participate between June 2016 and February 2017. The Child Health Questionnaire was used to assess the HR-QoL. A detailed questionnaire was used to assess the severity of headache symptoms. The control group consisted of 353 school children aged 5 to 14 years. RESULTS: In all, 95 parents of patients with SS were invited to participate, of whom 68 (71.6%) parents completed the CHQ-PF50. The mean age of the participating patients was 12.4 years (10.8 to 14.2). The Psychosocial- and Physical summary of the patients with SS was similar to the general population. In the distinct CHQ scales, "Family cohesion" ( P =0.02) was higher, and "Mental health" ( P =0.05) was lower compared with the general population. The type and timing of surgery did not affect the HR-QoL. Thirty-two patients (47.1%) reported having headache complaints at least once a month. The CHQ scores of SS patients with frequent headaches had a significantly lower score of mild to large effect than those without headaches. CONCLUSION: Patients with SS have a slightly lower to similar HR-QoL compared with the general population. In all, 47.1% of SS patients have frequent headaches, resulting in lower average HR-QoL. The type and timing of surgery did not affect the results. Clinicians should be aware of lower HR-QoL in some subgroups of patients with SS.

What We Know About Intracranial Hypertension in Children With Syndromic Craniosynostosis.

OBJECTIVE: A scoping review of literature about mechanisms leading to intracranial hypertension (ICH) in syndromic craniosynostosis (sCS) patients, followed by a narrative synopsis of whether cognitive and behavioral outcome in sCS is more related to genetic origins, rather than the result of ICH. METHODS: The scoping review comprised of a search of keywords in EMBASE, MEDLINE, Web of science, Cochrane Central Register of Trials, and Google scholar databases. Abstracts were read and clinical articles were selected for full-text review and data were extracted using a structured template. A priori, the authors planned to analyze mechanistic questions about ICH in sCS by focusing on 2 key aspects, including (1) the criteria for determining ICH and (2) the role of component factors in the Monro-Kellie hypothesis/doctrine leading to ICH, that is, cerebral blood volume, cerebrospinal fluid (CSF), and the intracranial volume. RESULTS: Of 1893 search results, 90 full-text articles met criteria for further analysis. (1) Invasive intracranial pressure measurements are the gold standard for determining ICH. Of noninvasive alternatives to determine ICH, ophthalmologic ones like fundoscopy and retinal thickness scans are the most researched. (2) The narrative review shows how the findings relate to ICH using the Monro-Kellie doctrine. CONCLUSIONS: Development of ICH is influenced by different aspects of sCS: deflection of skull growth, obstructive sleep apnea, venous hypertension, obstruction of CSF flow, and possibly reduced CSF absorption. Problems in cognition and behavior are more likely because of genetic origin. Cortical thinning and problems in visual function are likely the result of ICH.

Potential higher risk of tethered spinal cord in children after prenatal surgery for myelomeningocele: A systematic review and meta-analysis.

INTRODUCTION: We performed a systematic review and meta-analysis on the incidence of secondary tethered spinal cord (TSC) between prenatal and postnatal closure in patients with MMC. The objectives was to understand the incidence of secondary TSC after prenatal surgery for MMC compared to postnatal surgery for MMC. MATERIAL AND METHODS: On May 4, 2023, a systematic search was conducted in Medline, Embase, and the Cochrane Library to gather relevant data. Primary studies focusing on repair type, lesion level, and TSC were included, while non-English or non-Dutch reports, case reports, conference abstracts, editorials, letters, comments, and animal studies were excluded. Two reviewers assessed the included studies for bias risk, following PRISMA guidelines. TSC frequency in MMC closure types was determined, and the relationship between TSC occurrence and closure technique was analyzed using relative risk and Fisher's exact test. Subgroup analysis revealed relative risk differences based on study designs and follow-up periods. A total of ten studies, involving 2,724 patients, were assessed. Among them, 2,293 patients underwent postnatal closure, while 431 received prenatal closure for the MMC defect. In the prenatal closure group, TSC occurred in 21.6% (n = 93), compared to 18.8% (n = 432) in the postnatal closure group. The relative risk (RR) of TSC in patients with prenatal MMC closure versus postnatal MMC closure was 1.145 (95%CI 0.939 to 1.398). Fisher's exact test indicated a statistically non-significant association (p = 0.106) between TSC and closure technique. When considering only RCT and controlled cohort studies, the overall RR for TSC was 1.308 (95%CI 1.007 to 1.698) with a non-significant association (p = .053). For studies focusing on children up until early puberty (maximum 12 years follow-up), the RR for tethering was 1.104 (95%CI 0.876 to 1.391), with a non-significant association (p = 0.409). CONCLUSION AND DISCUSSION: This review found no significant increase in relative risk of TSC between prenatal and postnatal closure in MMC patients, but a trend of increased TSC in the prenatal group. More long-term data on TSC after fetal closure is needed for better counseling and outcomes in MMC.

Meaningful outcomes for children and their caregivers attending a paediatric brain centre.

AIM: To identify meaningful outcomes of children and their caregivers attending a paediatric brain centre. METHOD: We compiled a long list of outcomes of health and functioning of children with brain-related disorders such as cerebral palsy, spina bifida, (genetic) neurodevelopmental disorders, and acquired brain injury. We incorporated three perspectives: patients, health care professionals, and published outcome sets. An aggregated list was categorized using the International Classification of Functioning, Disability, and Health: Children and Youth version in a patient validation survey for children and parent-caregivers to prioritize outcomes. Outcomes were considered meaningful when ranked 'very important' by 70% or more of the participants. RESULTS: We identified 104 outcomes from the three perspectives. After categorizing, 59 outcomes were included in the survey. Thirty-three surveys were completed by children (n = 4), caregivers (n = 24), and parent-caregivers together with their child (n = 5). Respondents prioritized 27 meaningful outcomes covering various aspects of health and functioning: emotional well-being, quality of life, mental and sensory functions, pain, physical health, and activities (communication, mobility, self-care, interpersonal relationships). Parent-caregiver concerns and environmental factors were newly identified outcomes. INTERPRETATION: Children and parent-caregivers identified meaningful outcomes covering various aspects of health and functioning, including caregiver concerns and environmental factors. We propose including those in future outcome sets for children with neurodisability. WHAT THIS PAPER ADDS: Outcomes that children with brain-related disorders and their parent-caregivers consider to be the most meaningful cover a wide range of aspects of functioning. Involving these children and their parent-caregivers resulted in the identification of important outcomes that were not covered by professionals and the literature. Parent-caregiver-related factors (coping, burden of care) and environmental factors (support, attitudes, and [health care] services) were identified as meaningful.

Evaluation of AR visualization approaches for catheter insertion into the ventricle cavity.

Augmented reality (AR) has shown potential in computer-aided surgery. It allows for the visualization of hidden anatomical structures as well as assists in navigating and locating surgical instruments at the surgical site. Various modalities (devices and/or visualizations) have been used in the literature, but few studies investigated the adequacy/superiority of one modality over the other. For instance, the use of optical see-through (OST) HMDs has not always been scientifically justified. Our goal is to compare various visualization modalities for catheter insertion in external ventricular drain and ventricular shunt procedures. We investigate two AR approaches: (1) 2D approaches consisting of a smartphone and a 2D window visualized through an OST (Microsoft HoloLens 2), and (2) 3D approaches consisting of a fully aligned patient model and a model that is adjacent to the patient and is rotationally aligned using an OST. 32 participants joined this study. For each visualization approach, participants were asked to perform five insertions after which they filled NASA-TLX and SUS forms. Moreover, the position and orientation of the needle with respect to the planning during the insertion task were collected. The results show that participants achieved a better insertion performance significantly under 3D visualizations, and the NASA-TLX and SUS forms reflected the preference of participants for these approaches compared to 2D approaches.

Trapped fourth ventricle: to stent, shunt, or fenestrate-a systematic review and individual patient data meta-analysis.

Trapped or isolated fourth ventricle (TFV) is a rare but critical neurosurgical condition, mostly occurring in pediatric patients, caused by a blockage of the in- and outlets of the fourth ventricle. The purpose of this study is to review all available data on the treatment options of TFV and to compare their safety, efficacy, and durability. MEDLINE, Embase, and Google Scholar were searched from inception to September 13, 2022, for prospective or retrospective cohorts, case-control studies, case series or case reports, reporting detailing outcomes of TFV patients, treated with an endoscopic-, microsurgical-, shunt placement,- or hybrid approaches to TFV. All authors were contacted to provide individual patient data. Eighty-seven articles (314 patients) were included in the individual patient data meta-analysis (IPD) and 9 (151 patients) in the cohort meta-analysis. The IPD revealed that primary endoscopic (aOR 0.21; [95% CI 0.08-0.57]) and microsurgical interventions (aOR 0.21; [95% CI 0.05-0.82]) were associated with a significantly lower revision rate, compared to shunt placement, when adjusted for confounders. Endoscopy was also associated with a significantly higher rate of clinical improvement (aOR 4.56; [95% CI 1.2-18]). The meta-analysis revealed no significant difference in revision rate between the endoscopic (0.33 [95% CI 0.0-0.52]) and shunt group (0.44 [95% CI 0.0-1.0]). Endoscopy should be considered as the first-line treatment of TFV due to its superior efficacy, durability, and similar safety, compared to shunt placement and its minimally invasive nature. Microsurgery should be considered as a second treatment option, due to its similar clinical outcomes and revision rate as endoscopy, but it is more invasive in nature.

Newborns with myelomeningocele: their health-related quality of life and daily functioning 10 years later.

OBJECTIVE: Ten years ago, the authors reported on the outcome of their study investigating the degree of discomfort and pain in newborns with myelomeningocele (MMC), using the parameters of unbearable and hopeless suffering. In the current study, they investigated the quality of life, daily functioning, pain and fatigue, ability to communicate, and number of surgeries in the same cohort of patients. They subdivided their study population into severe (Lorber) and less severe (non-Lorber) cases and compared these cases with a healthy population (non-MMC group) and with each other. METHODS: The parents of 22 of 28 patients gave informed consent for this study. The KIDSCREEN-27 and PEDI-CAT (Pediatric Evaluation of Disability Inventory) were used to assess quality of life and daily functioning. Pain and fatigue were self-reported on a 10-point numeric rating scale. Communication and ambulation levels were determined using the Communication Function Classification System (CFCS) and the Hoffer ambulation scale. Using reference data from the KIDSCREEN-27 and PEDI-CAT, the authors created a healthy population comparison group. RESULTS: There was no significant difference in health-related quality-of-life (HRQOL) scores between Lorber and non-Lorber patients, except that school environment domain scores were lower in the Lorber group. When comparing the HRQOL of MMC patients with that of the non-MMC group, the physical well-being and parent relations and autonomy domains scored significantly lower. The daily functioning of MMC patients was lower on all domains of the PEDI-CAT compared with the non-MMC group. Lorber MMC patients scored lower on all domains of the PEDI-CAT when compared with non-Lorber patients. All patients were capable of communicating effectively; most patients (n = 18) were considered CFCS level I, and 4 patients were considered CFCS level II. CONCLUSIONS: This study shows that MMC is a severe, lifelong condition that affects patients' lives in many domains. All the patients in this study are capable of effective communication, irrespective of severity of MMC. Overall, the data show that in newborn MMC patients, future unbearable suffering with respect to pain, mobility, cognition, and communication is hard to predict and may not always occur.

Early and long-term skull growth after surgical correction for sagittal synostosis in relation to the occurrence of papilledema.

OBJECTIVE: Stagnation of skull growth is correlated with papilledema in craniosynostosis. In this retrospective cohort study, we describe the postoperative skull growth after surgical correction for sagittal synostosis and its relation to the development of papilledema. METHODS: Patients with isolated sagittal synostosis at our center between 2005 and 2012 were included. Occipitofrontal circumference (OFC) was analyzed, at 3 time points (preoperative, 2 years postoperative, and last OFC measurement) and 3 phases (initial postoperative growth, long-term growth, and overall growth), and related to papilledema on fundoscopy. RESULTS: In total, 163 patients were included. The first time interval showed a decline in skull growth, with subsequent stabilization at long term. Papilledema occurred postoperatively in 10 patients. In these patients, the OFC at 2 years and at last follow-up (T3) were significantly smaller than in patients without papilledema. A larger OFC resulted in a decreased odds of developing papilledema at both postoperative time points (at T2 (OR = 0.40, p = 0.01) and at T3 (OR 0.29, p < 0.001)). Sensitivity and specificity analysis indicated that an OFC below 0.25 SD at T2 (sensitivity 90%, specificity 65%) and below 0.49 at T3 (sensitivity 100%, specificity 60%) are related to the occurrence of papilledema. CONCLUSION: A small OFC is correlated with the occurrence of papilledema. A decline in OFC within 2 years postoperatively is common in sagittal synostosis and is acceptable up to a value of 0.25SD. Patients with an OFC at last follow-up of less than 0.5SD are at risk for developing papilledema.

The use of OCT to detect signs of intracranial hypertension in patients with sagittal suture synostosis: Reference values and correlations.

PURPOSE: To obtain pediatric normative reference values and determine whether optical coherence tomography (OCT) corresponds better with clinical signs of intracranial hypertension (ICH) compared to the traditional screening method fundoscopy in a large cohort of one type of single suture craniosynostosis. METHODS: Control subjects without optic nerve diseases and isolated sagittal synostosis patients aged 3-10 years who underwent fundoscopy and OCT were included in this prospective cohort study. Normative reference values were obtained through bootstrap analysis. Main outcome was the association between peripapillary total retinal thickness (TRT) and total retinal volume (TRV) and appearance on fundoscopy. Signs and symptoms suggestive of ICH, including skull growth arrest, fingerprinting, and headache, were scored. RESULTS: Sixty-four healthy controls and 93 isolated sagittal synostosis patients were included. Normative cut-off values for mean TRT are < 256 µm and > 504 µm and for mean TRV < 0.21 mm3 and > 0.39 mm3. TRT was increased in 16 (17%) and TRV in 15 (16%) of 93 patients, compared to only 4 patients with papilledema on fundoscopy (4%). Both parameters were associated with papilledema on fundoscopy (OR = 16.7, p = 0.02, and OR = 18.2, p = 0.01). Skull growth arrest was significantly associated with abnormal OCT parameters (OR = 13.65, p < 0.01). CONCLUSIONS: The established cut-off points can be applied to screen for ICH in pediatrics. The present study detected abnormalities with OCT more frequent than with fundoscopy, which were associated with skull growth arrest. Therefore, a combination of OCT, fundoscopy, and skull growth arrest can improve clinical decision-making in craniosynostosis.

Augmented reality navigation for minimally invasive craniosynostosis surgery: a phantom study.

PURPOSE: In minimally invasive spring-assisted craniectomy, surgeons plan the surgery by manually locating the cranial sutures. However, this approach is prone to error. Augmented reality (AR) could be used to visualize the cranial sutures and assist in the surgery planning. The purpose of our work is to develop an AR-based system to visualize cranial sutures, and to assess the accuracy and usability of using AR-based navigation for surgical guidance in minimally invasive spring-assisted craniectomy. METHODS: An AR system was developed that consists of an electromagnetic tracking system linked with a Microsoft HoloLens. The system was used to conduct a study with two skull phantoms. For each phantom, five sutures were annotated and visualized on the skull surface. Twelve participants assessed the system. For each participant, model alignment using six anatomical landmarks was performed, followed by the participant delineation of the visualized sutures. At the end, the participants filled a system usability scale (SUS) questionnaire. For evaluation, an independent optical tracking system was used and the delineated sutures were digitized and compared to the CT-annotated sutures. RESULTS: For a total of 120 delineated sutures, the distance of the annotated sutures to the planning reference was [Formula: see text] mm. The average delineation time per suture was [Formula: see text] s. For the system usability questionnaire, an average SUS score of 73 was obtained. CONCLUSION: The developed AR-system has good accuracy (average 2.4 mm distance) and could be used in the OR. The system can assist in the pre-planning of minimally invasive craniosynostosis surgeries to locate cranial sutures accurately instead of the traditional approach of manual palpation. Although the conducted phantom study was designed to closely reflect the clinical setup in the OR, further clinical validation of the developed system is needed and will be addressed in a future work.

A Diffusion Tensor Imaging Analysis of Frontal Lobe White Matter Microstructure in Trigonocephaly Patients.

BACKGROUND: Children with trigonocephaly are at risk for neurodevelopmental disorders. The aim of this study is to investigate white matter properties of the frontal lobes in young, unoperated patients with metopic synostosis as compared to healthy controls using diffusion tension imaging (DTI). METHODS: Preoperative DTI data sets of 46 patients with trigonocephaly with a median age of 0.49 (interquartile range: 0.38) years were compared with 21 controls with a median age of 1.44 (0.98) years. White matter metrics of the tracts in the frontal lobe were calculated using FMRIB Software Library (FSL). The mean value of tract-specific fractional anisotropy (FA) and mean diffusivity (MD) were estimated for each subject and compared to healthy controls. By linear regression, FA and MD values per tract were assessed by trigonocephaly, sex, and age. RESULTS: The mean FA and MD values in the frontal lobe tracts of untreated trigonocephaly patients, younger than 3 years, were not significantly different in comparison to controls, where age showed to be a significant associated factor. CONCLUSIONS: Microstructural parameters of white matter tracts of the frontal lobe of patients with trigonocephaly are comparable to those of controls aged 0-3 years.

Cerebral Blood Flow of the Frontal Lobe in Untreated Children with Trigonocephaly versus Healthy Controls: An Arterial Spin Labeling Study.

BACKGROUND: Craniofacial surgery is the standard treatment for children with moderate to severe trigonocephaly. The added value of surgery to release restriction of the frontal lobes is unproven, however. In this study, the authors aim to address the hypothesis that the frontal lobe perfusion is not restricted in trigonocephaly patients by investigating cerebral blood flow. METHODS: Between 2018 and 2020, trigonocephaly patients for whom a surgical correction was considered underwent magnetic resonance imaging brain studies with arterial spin labeling to measure cerebral perfusion. The mean value of cerebral blood flow in the frontal lobe was calculated for each subject and compared to that of healthy controls. RESULTS: Magnetic resonance imaging scans of 36 trigonocephaly patients (median age, 0.5 years; interquartile range, 0.3; 11 female patients) were included and compared to those of 16 controls (median age, 0.83 years; interquartile range, 0.56; 10 female patients). The mean cerebral blood flow values in the frontal lobe of the trigonocephaly patients (73.0 ml/100 g/min; SE, 2.97 ml/100 g/min) were not significantly different in comparison to control values (70.5 ml/100 g/min; SE, 4.45 ml/100 g/min; p = 0.65). The superior, middle, and inferior gyri of the frontal lobe showed no significant differences either. CONCLUSIONS: The authors' findings suggest that the frontal lobes of trigonocephaly patients aged less than 18 months have a normal cerebral blood flow before surgery. In addition to the very low prevalence of papilledema or impaired skull growth previously reported, this finding further supports the authors' hypothesis that craniofacial surgery for trigonocephaly is rarely indicated for signs of raised intracranial pressure or restricted perfusion for patients younger than 18 months. CLINICAL QUESTION/LEVEL OF EVIDENCE: Risk, II.

The Course and Interaction of Ventriculomegaly and Cerebellar Tonsillar Herniation in Crouzon Syndrome over Time.

Children with Crouzon syndrome have a higher incidence of cerebellar tonsillar herniation (TH) and ventriculomegaly than the general population, or children with other craniosynostosis syndromes. OBJECTIVE: This retrospective cohort study aimed to determine how ventriculomegaly and TH develop and progress over time, and determine associations between ventriculomegaly and TH in Crouzon patients, treated according to our center's protocol. METHODS: Fronto-occipital horn ratio (FOHR) and TH were determined over time using brain-imaging. These data were used to fit a mixed-model to determine associations between them, and with clinical variables, head-circumference, and lambdoid suture synostosis. RESULTS: Sixty-three Crouzon patients were included in this study. Preoperatively, 28% had ventriculomegaly, and 11% had TH ≥ +5 mm. Postoperatively ventriculomegaly increased to 49%. Over time and with treatment, FOHR declined and stabilized around 5 years of age. TH ≥ +5 mm increased to 46% during follow-up. FOHR and TH were associated: expected FOHR with a TH of either 0 mm versus +8.6 mm at 0 years: 0.44 versus 0.49, and at 5 years: 0.34 versus 0.38; 10% increase of FOHR was associated with 1.6 mm increase in TH. Increased head-circumference was associated with increased FOHR. Lambdoid suture synostosis was associated with +6.9 mm TH increase. CONCLUSIONS: In Crouzon patients, FOHR was large at onset and decreased and stabilized with treatment and time. FOHR was associated with head-circumference and TH. TH was strongly associated with lambdoid suture synostosis and FOHR. Increased head-circumference was associated with an increased FOHR, and closed lambdoid sutures before 1 year of age were associated with a +6.92 mm increase in tonsil position.