OBJECTIVE: This study aims to evaluate the effectiveness of the Piezosurgery® device in endoscopic-assisted correction of trigonocephaly. Trigonocephaly is a type of craniosynostosis characterized by a triangular-shaped forehead due to the premature fusion of the metopic suture. Traditional open cranial vault reconstruction, although common, is invasive and poses risks. The study explores a less invasive alternative using ultrasonic microvibrations for bone cutting, potentially reducing soft tissue damage and improving surgical outcomes.
METHODS: The Piezosurgery® device was employed in endoscopic trigonocephaly correction surgeries performed on patients under 4 months old at the French Referral Center for Craniosynostosis in Lyon. The technique involves making a small skin incision and performing osteotomies from the anterior fontanel to the glabella. A rigid 0° endoscope provides visibility, and the Piezosurgery® device enables precise bone cutting while preserving the dura mater. Post-surgery, patients were discharged within 3 days and required to wear a remodeling helmet for 6-8 months.
RESULTS: The use of Piezosurgery® device allowed precise osteotomies with minimal soft tissue damage. No dura mater injuries occurred in the patient series. The procedure was efficient, with an average duration of 80 min, and blood loss was minimal, reducing the need for blood transfusions. The endoscopic approach facilitated shorter surgical times and reduced postoperative infection risks. Enhanced visibility during surgery, due to cavitation effects, improved the accuracy of bone cuts. The technique demonstrated promising safety and esthetic outcomes, although it incurred higher costs compared to traditional methods.
CONCLUSIONS: Piezosurgery® device provides a safe and effective method for minimally invasive endoscopic correction of trigonocephaly. The device\'s ability to selectively cut bone while preserving soft tissues offers significant advantages, despite longer surgical times and higher costs. This technique represents a viable alternative to traditional open surgery, promoting better clinical outcomes and reduced recovery times.

OBJECTIVE: Trigonocephaly is the most common craniosynostosis involving orbits. Although some degree of agreement has been reached regarding surgical timing and indications for treatment, there is no consensus regarding the ideal operative technique to guarantee an optimal morphological outcome. The purpose of this study is to describe both strategies and to compare morphological outcomes by means of morphological surface analysis obtained from three-dimensional (3D) stereophotogrammetry, with two different techniques.
METHODS: We retrospectively investigated 43 patients with metopic synostosis surgically treated between 2004 and 2020. Two different techniques were applied, addressed as technique A and B. Ten patients undergone postoperative 3d stereophotogrammetry were enrolled, and cephalometric measurements were taken and compared to a cohort of unaffected patients matched by age and gender.
RESULTS: Comparison of the groups demonstrated a hypercorrection of the metopic angle of the second technique, associated with a slightly lower correction of the interfrontoparietal diameter. The metopic angle showed to be significantly undercorrected with the first method.
CONCLUSIONS: Alternated barrel staving technique appears to be a quick and satisfactory method in cranial remodelling for metopic synostosis. It guarantees an optimal aesthetic result in the first years after surgery.

The aim of this study was to compare a traditional fronto-orbital remodeling and advancement (FORA) with the dynamic cranioplasty for trigonocephaly (DCT). The authors analyzed patients who underwent surgery for trigonocephaly. Perioperative data were compared. Parents were asked to use a visual analog scale to evaluate the pre- and postoperative distance between the eyes, the forehead shape, and the global appearance of the face. A panel of observers was asked to grade pre- and postoperative photographs using a similar visual analog scale. Pre- and postoperative anthropometric data were collected and analyzed in a subset of the study population aged 9 years or older. The total sample size was 51 patients (DCT n = 39; FORA n = 12). Durations of surgery and anesthesia were shorter in the DCT group (115 vs 194 min, p = 0.001; 226 vs 289 min, p = 0.001). Patients in the DCT group received similar preoperative ratings to those in the FORA group, but significantly higher postoperative ratings by parents for all three questions. There were no significant differences in postoperative ratings by the panel or postoperative anthropometric data. DCT is safe and effective. It is preferred over FORA because it is associated with shorter durations of surgery and anesthesia, while providing higher degrees of parental satisfaction and similar aesthetic and anthropometric outcomes.

BACKGROUND: The association between trigonocephaly and Sylvian fissure arachnoid cysts (ACs) has been occasionally reported in the literature. However, the real incidence of this association and its clinical relevance remain unknown.
METHODS: The authors collected and retrospectively reviewed all clinical charts and CT scans of patients surgically treated for trigonocephaly at the Pediatric Neurosurgical Department of Fondazione Policlinico Universitario \"Agostino Gemelli\" IRCCS from January 2014 to June 2023.
RESULTS: During the study period, 136 patients with trigonocephaly underwent surgery. Analysis of the clinical charts revealed that in 39.7% of the cases (54/136), preoperative CT scan depicted the presence of a Sylvian fissure AC. Of these, AC was bilateral in 23 cases and unilateral in the remaining 31. All unilateral ACs were on the left side. The ACs were classified as Galassi grade I in 52 cases (96.3%) and Galassi grade II in 2 cases (3.7%). Interestingly, in 1 case we reported a Galassi grade I AC enlargement during follow-up, thereby necessitating surgical fenestration.
CONCLUSIONS: ACs and trigonocephaly are well-known conditions for pediatric neurosurgeons; however, their association is poorly defined. Despite the lack of reports on the incidence and clinical significance of this association, it is worth knowing that radiological follow-up is essential in monitoring AC evolution.

Metopic synostosis patients are at risk for neurodevelopmental disorders despite a negligible risk of intracranial hypertension. To gain insight into the underlying pathophysiology of metopic synostosis and associated neurodevelopmental disorders, we aimed to investigate brain volumes of non-syndromic metopic synostosis patients using preoperative MRI brain scans. MRI brain scans were processed with HyperDenseNet to calculate total intracranial volume (TIV), total brain volume (TBV), total grey matter volume (TGMV), total white matter volume (TWMV) and total cerebrospinal fluid volume (TCBFV). We compared global brain volumes of patients with controls corrected for age and sex using linear regression. Lobe-specific grey matter volumes were assessed in secondary analyses. We included 45 metopic synostosis patients and 14 controls (median age at MRI 0.56 years [IQR 0.36] and 1.1 years [IQR 0.47], respectively). We found no significant differences in TIV, TBV, TGMV or TCBFV in patients compared to controls. TWMV was significantly smaller in patients (-62,233 mm3 [95% CI = -96,968; -27,498], Holm-corrected p = 0.004), and raw data show an accelerated growth pattern of white matter in metopic synostosis patients. Grey matter volume analyses per lobe indicated increased cingulate (1378 mm3 [95% CI = 402; 2355]) and temporal grey matter (4747 [95% CI = 178; 9317]) volumes in patients compared to controls. To conclude, we found smaller TWMV with an accelerated white matter growth pattern in metopic synostosis patients, similar to white matter growth patterns seen in autism. TIV, TBV, TGMV and TCBFV were comparable in patients and controls. Secondary analyses suggest larger cingulate and temporal lobe volumes. These findings suggest a generalized intrinsic brain anomaly in the pathophysiology of neurodevelopmental disorders associated with metopic synostosis.

Positional cranial deformities are a common finding in toddlers, yet differentiation from craniosynostosis can be challenging. The aim of this study was to train convolutional neural networks (CNNs) to classify craniofacial deformities based on 2D images generated using photogrammetry as a radiation-free imaging technique. A total of 487 patients with photogrammetry scans were included in this retrospective cohort study: children with craniosynostosis (n = 227), positional deformities (n = 206), and healthy children (n = 54). Three two-dimensional images were extracted from each photogrammetry scan. The datasets were divided into training, validation, and test sets. During the training, fine-tuned ResNet-152s were utilized. The performance was quantified using tenfold cross-validation. For the detection of craniosynostosis, sensitivity was at 0.94 with a specificity of 0.85. Regarding the differentiation of the five existing classes (trigonocephaly, scaphocephaly, positional plagiocephaly left, positional plagiocephaly right, and healthy), sensitivity ranged from 0.45 (positional plagiocephaly left) to 0.95 (scaphocephaly) and specificity ranged from 0.87 (positional plagiocephaly right) to 0.97 (scaphocephaly). We present a CNN-based approach to classify craniofacial deformities on two-dimensional images with promising results. A larger dataset would be required to identify rarer forms of craniosynostosis as well. The chosen 2D approach enables future applications for digital cameras or smartphones.

Background: The last several decades have witnessed an increase in metopic craniosynostosis incidence. Population-based studies suggest that pharmacological exposure in utero may be responsible. This study examined effects of the fertility drug clomiphene citrate (CC) on calvarial development in an established model for craniofacial development, the zebrafish Danio rerio. Results: Zebrafish larvae were exposed to clomiphene citrate or its isomer enclomiphene for five days at key points during calvarial development. Larvae were then raised to adulthood in normal rearing water. Zebrafish were analyzed using whole-mount skeletal staining. We observed differential effects on survivability, growth and suture formation depending on the treatment. Treatments with CC or enclomiphene at 5.5 mm SL led to increased fusion of the interfrontal suture (p < .01) compared to controls. Conclusions: Exposure to fertility drugs appears to affect development of the cranial vault, specifically the interfrontal suture, in zebrafish. Further research is required to identify the signaling mechanisms at play. This work suggests that fertility drug treatment may contribute to the increased incidence of metopic craniosynostosis observed globally.
Historique : L’incidence de craniosynostoses métopiques a augmenté ces dernières décennies. D’après les études en population, l’exposition aux médicaments in utero pourrait en être responsable. La présente étude traite des effets d’un agent ovulatoire, le citrate de clomifène (CC), sur le développement de la voûte crânienne d’un modèle établi de développement crâniofacial, le poisson-zèbre Danio rerio. Résultats : Les chercheurs ont exposé des larves de poisson-zèbre au citrate de clomifène ou à son isomère, l’enclomiphène, sur une période de cinq jours à des moments clés du développement de la voûte crânienne. Ils les ont ensuite élevés jusqu’à l’âge adulte dans de l’eau normale. Ils ont analysé les poissons-zèbres par coloration du squelette entier et observé des effets différentiels sur la capacité de survie, la croissance et la formation des sutures en fonction du traitement. Les traitements au CC ou à l’enclomiphène d’une longueur standard de 5,5 mm ont entraîné une fusion accrue de la suture métopique (p < 0,01) par rapport aux sujets témoins. Conclusions : L’exposition aux agents ovulatoires semble influer sur le développement de la voûte crânienne, notamment la suture métopique, chez le poisson-zèbre. D’autres recherches devront être réalisées pour déterminer les mécanismes de signalisation en jeu. Selon la présente étude, les agents ovulatoires peuvent contribuer à l’incidence accrue de craniosynostose métopique sur la scène mondiale.

Ridging along the metopic suture line can be a common cause of concern for parents and has been theorized to represent a mild form of trigonocephaly, a cranial deformity associated with risks of negative cosmetic outcomes, if not surgically corrected. Yet the literature contains sparse reports of long-term cosmetic results or expectations for infants with isolated metopic ridging compared with those with severe trigonocephaly, or even what objective metrics discriminate isolated metopic ridging from severe trigonocephaly. Therefore, the authors\' goals for this study were to 1) quantify the degree of frontal deformity among patients with metopic ridge, metopic craniosynostosis, and normocephalic head shapes; and 2) document the natural history of frontal deformities in isolated metopic ridge patients in the 1st year of life.
This was a retrospective cohort study of patients with normocephalic head shapes, metopic ridges, and metopic craniosynostoses who presented at < 1 year of age to the Connecticut Children\'s neurosurgery clinic from January 2019 to December 2021. Data were collected regarding demographics and photograph-based craniometrics.
A total of 212 normocephalic, 34 metopic ridge, and 29 metopic craniosynostosis patients were included. Both the normocephalic and metopic ridge groups had a significantly higher anterior arc angle (AAA) value compared with the metopic craniosynostosis group (p < 0.0001). The AAA did not differ significantly among normocephalic patients and those with ridging. Over the course of 1 year of follow-up, patients with metopic ridging demonstrated a slight decrease in AAA values, but overall remained within the same range as normocephalic patients.
Photograph-based craniometrics suggest that metopic ridge patients with frontal bone angulations > 2.2 radians have a mild degree of frontal constriction that does not significantly worsen over the 1st year of life.

We present a novel method for the morphometric analysis of series of 3D shapes, and demonstrate its relevance for the detection and quantification of two craniofacial anomalies: trigonocephaly and metopic ridges, using CT-scans of young children. Our approach is fully automatic, and does not rely on manual landmark placement and annotations. Our approach furthermore allows to differentiate shape classes, enabling successful differential diagnosis between trigonocephaly and metopic ridges, two related conditions characterized by triangular foreheads. These results were obtained using recent developments in automatic nonrigid 3D shape correspondence methods and specifically spectral approaches based on the functional map framework. Our method can capture local changes in geometric structure, in contrast to methods based, for instance, on global shape descriptors. As such, our approach allows to perform automatic shape classification and provides visual feedback on shape regions associated with different classes of deformations. The flexibility and generality of our approach paves the way for the application of spectral methods in quantitative medicine.

Metopic ridge (MeR) is a midline osseous forehead prominence resulting from physiologic closure of the underlying metopic suture. This mass-like ridge can be mistaken for serious conditions such as a craniosynostosis or vascular anomaly, prompting concern and workup. We reviewed patients presenting for a forehead mass to Vascular Anomalies and Dermatology clinics and diagnosed with MeR to increase familiarity with this finding and to encourage MeR in the differential diagnosis of pediatric midline forehead masses.