Practical Computed Tomography Scan Findings for Distinguishing Metopic Craniosynostosis from Metopic Ridging

Validating the Supraorbital Notch-Nasion-Supraorbital Notch Angle as a Marker for Metopic Craniosynostosis Severity

OBJECTIVE

Metopic craniosynostosis (MCS) can be difficult to differentiate from metopic ridge (MR) or normal frontal morphology. This study assess whether the supraorbital notch-nasion-supraorbital notch (SNS) angle can help identify MCS.

METHODS

Records of 212 patients with preoperative three-dimensional computed tomography scans were examined. The SNS angles, surgeon craniofacial dysmorphology rankings, and CranioRate metopic severity scores (MSSs) were compared with the Spearman rank correlation coefficient. Receiver operating characteristic (ROC) curves with Youden J-statistic and cross-validation of regression models assessed the ability of these measures to predict surgery.

RESULTS

A total of 212 patients were included, consisting of 78 MCS, 37 MR, and 97 controls. Both the mean SNS angle (MCS: 111.7 ± 10.7 degrees, MR: 126.0 ± 8.2 degrees, controls: 130.7 ± 8.8 degrees P < 0.001) and MSS (MCS: 5.9 ± 2.0, MR: 1.4 ± 1.9, controls: 0.2 ± 1.9, P < 0.001) were different among the cohorts. The mean SNS angle (111.5 ± 10.7 versus 129.1 ± 8.8, P < 0.001) was lower in those who had surgery and CranioRate score (5.9 ± 2.1 versus 0.8 ± 2.2, P < 0.001) was higher in those who underwent surgery. SNS angles were positively correlated with surgeon craniofacial dysmorphology rankings ( r = 0.41, P < 0.05) and CranioRate MSS ( r = 0.54, P < 0.05). The ROC curve requiring high sensitivity revealed an SNS angle of 124.8 degrees predicted surgery with a sensitivity of 88.7% and a specificity of 71.3%. A ROC curve using the CranioRate MCC values ≥3.19 predicted surgery with 88.7% sensitivity and 94.7% specificity.

CONCLUSION

Orbital dysmorphology in patients with MCS is well captured by the supraorbital-nasion angle. Both the SNS angle and CranioRate MSS scores accurately predict surgical intervention.

New diagnostic criteria for metopic ridges and trigonocephaly: a 3D geometric approach

BACKGROUND

Trigonocephaly occurs due to the premature fusion of the metopic suture, leading to a triangular forehead and hypotelorism. This condition often requires surgical correction for morphological and functional indications. Metopic ridges also originate from premature metopic closure but are only associated with mid-frontal bulging; their surgical correction is rarely required. Differential diagnosis between these two conditions can be challenging, especially in minor trigonocephaly.

METHODS

Two hundred seven scans of patients with trigonocephaly (90), metopic rigdes (27), and controls (90) were collected. Geometric morphometrics were used to quantify skull and orbital morphology as well as the interfrontal angle and the cephalic index. An innovative method was developed to automatically compute the frontal curvature along the metopic suture. Different machine-learning algorithms were tested to assess the predictive power of morphological data in terms of classification.

RESULTS

We showed that control patients, trigonocephaly and metopic rigdes have distinctive skull and orbital shapes. The 3D frontal curvature enabled a clear discrimination between groups (sensitivity and specificity > 92%). Furthermore, we reached an accuracy of 100% in group discrimination when combining 6 univariate measures.

CONCLUSION

Two diagnostic tools were proposed and demonstrated to be successful in assisting differential diagnosis for patients with trigonocephaly or metopic ridges. Further clinical assessments are required to validate the practical clinical relevance of these tools.

Exploring Different Management Modalities of Nonsyndromic Craniosynostosis

Craniosynostosis is an atypical skull shape characterized by the premature fusion of cranial sutures. It is one of the most common congenital anomalies encountered by craniofacial surgeons, with a prevalence of one in every 2000-2500 births. It is classified into two main types: syndromic and nonsyndromic. In syndromic, the patient presents with other abnormalities involving the trunk, face, or extremities. While in nonsyndromic the only anomy is the premature fusion, which usually involves one suture; the most common subtypes are unicoronal, sagittal, bicoronal, metopic, and lambdoid. As a consequence, premature fusion before its natural time restricts the space for the brain to grow, increases intracranial pressure, causes damage to the brain tissue, and affects the development of the child. This review comprehensively provides a detailed overview of nonsyndromic craniosynostosis and aims to highlight the importance of early and accurate diagnosis, and determining the most suitable intervention, whether surgical or conservative modalities. The optimal treatment approach produces the most favorable aesthetic and functional outcomes.

Assessing craniofacial growth and form without landmarks: A new automatic approach based on spectral methods

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.

Anthropometric cranial measurements in metopic craniosynostosis/trigonocephaly: diagnostic criteria, classification of severity and indications for surgery

ABSTRACT

Metopic craniosynostosis is the second most frequent type of craniosynostosis. When the phenotypic presentation has been deemed severe the treatment is surgical in nature and is performed in infancy with fronto-orbital advancement and cranial vault remodeling. At the time of this writing, there is no consensus regarding an objective evaluation system for severity, diagnostic criteria, or indications for surgery. This study aims to review the anthropometric cranial measurements and the relative diagnostic criteria/classification of severity/surgical indications proposed so far for this skull malformation, and to investigate if there is any scientific support for their utility.

Appropriateness of Computed Tomography Scanning in the Diagnosis of Craniosynostosis

INTRODUCTION

Although physicians from a variety of specialties encounter infants with possible craniosynostosis, judicious use of computed tomography (CT) imaging is important to avoid unnecessary radiation exposure and healthcare expense. The present study seeks to determine whether differences in specialty of ordering physician affects frequency of resulting diagnostic confirmations requiring operative intervention.

METHODS

Radiology databases from 2 institutions were queried for CT reports or indications that included "craniosynostosis" or "plagiocephaly." Patient demographics, specialty of ordering physician, confirmed diagnosis, and operative interventions were recorded. Cost analysis was performed using the fixed unit cost for a head CT to calculate the expense before 1 study led to operative intervention.

RESULTS

Three hundred eighty-two patients were included. 184 (48.2%) CT scans were ordered by craniofacial surgeons, 71 (18.6%) were ordered by neurosurgeons, and 127 (33.3%) were ordered by pediatricians. One hundred four (27.2%) patients received a diagnosis of craniosynostosis requiring operative intervention. Craniofacial surgeons and neurosurgeons were more likely than pediatricians to order CT scans that resulted in a diagnosis of craniosynostosis requiring operative intervention (P < 0.001), with no difference between craniofacial surgeons and neurosurgeons (P = 1.0). The estimated cost of obtaining an impact CT scan when ordered by neurosurgeons or craniofacial surgeons as compared to pediatricians was $2369.69 versus $13,493.75.

CONCLUSIONS

Clinicians who more frequently encounter craniosynostosis (craniofacial and neurosurgeons) had a higher likelihood of ordering CT images that resulted in a diagnosis of craniosynostosis requiring operative intervention. This study should prompt multi-disciplinary interventions aimed at improving evaluation of pretest probability before CT imaging.

Distinguishing Between Lambdoid Craniosynostosis and Deformational Plagiocephaly: A Review of This Paradigm Shift in Clinical Decision-Making and Lesson for the Future

The cause of occipital asymmtery can be either extrinsic or intrinsic. Intrinsic causes include lambdoid craniosynsotosis. This condition is generally treated with cranial vault expansion surgery. Extrinsic causes include deformational plagiocephaly, which became commonplace after the "Back to Sleep Campaign" instituted in the 1980s by the American Academy of Pediatrics. The treatment of this condition is non surgical. Dr. Joseph Gruss was instumental in differentiating between these conditions and reducing the number of unnecessary surgeries that were previously being performed.

A Comparison of Intracranial Volumes and Metopic Index in Patients With Isolated Metopic Ridge, Metopic Craniosynostosis, and Normal Healthy Children

BACKGROUND

Previous research has shown that patients with metopic craniosynostosis have significantly reduced intracranial volumes (ICVs) compared to normal healthy children. Furthermore, the metopic index (ratio of midfrontozygomatic diameter to maximal cranial width) has been described as an anthropometric cranial index for patients with metopic craniosynostosis. We aimed to determine whether patients with isolated metopic ridge have significantly different ICVs or metopic indices than normal children and patients with metopic craniosynostosis.

METHODS

A retrospective chart review of all patients with a diagnosis of a metopic ridge or metopic craniosynostosis was performed from 2000 to 2015 at Rady Children's Hospital. Patients were grouped based on computed tomographic scans consistent with metopic craniosynostosis versus metopic ridge.

RESULTS

Data were available for 15 metopic ridge patients, 74 metopic craniosynostosis patients, and 213 normal patients. Mean metopic ridge ICV was greater than mean metopic craniosynostosis ICV at 4 to 6 months and 7 to 12 months. Controlling for age and sex, the difference in ICV associated with metopic ridging was 197.484 cm3 and 137.770 cm3 at 4 to 6 and 7 to 12 months, respectively. Similarly, mean metopic index was significantly greater in metopic ridge patients compared to mean metopic craniosynostosis at 4 to 6 months and at 7 to 12 months.

CONCLUSIONS

Our study provides volumetric and anthropometric data to support the hypothesis that isolated metopic ridge is an intermediate phenotype between metopic craniosynostosis and normal cranial anatomy. We hope that characterizing the spectrum of disease involving premature closure of the metopic suture with regard to ICV and metopic index will aid physicians in their management of patients with isolated metopic ridge.