Premature closure of the metopic suture results in a growth restriction of the frontal bones, which leads to a skull malformation known as trigonocephaly. Over the course of recent decades, its incidence has been rising, currently making it the second most common type of craniosynostosis. Treatment consists of a cranioplasty, usually preformed before the age of 1 year. Metopic synostosis is linked with an increased level of neurodevelopmental delays. Theories on the etiology of these delays range from a reduced volume of the anterior cranial fossa to intrinsic malformations of the brain. This paper aims to provide an overview of this entity by giving an update on the epidemiology, etiology, evolution of treatment, follow-up, and neurodevelopment of metopic synostosis.

Metopic synostosis is thought to have an incidence of about 1 in 15,000 births. Traditionally, this makes it the third most frequent single-suture craniosynostosis, after scaphocephaly (1 in 4200-8500) and plagiocephaly (1 in 11,000). Our units have, independently from each other, noted a marked increase in the number of metopic synostosis over the recent years. This is a pan-European, retrospective epidemiological study on the number of cases with metopic synostosis born between January 1, 1997, and January 1, 2006. This number was compared to the prevalence of scaphocephaly, the most frequently seen craniosynostosis. In the 7 units, a total of 3240 craniosynostosis were seen from 1997 until 2006. Forty-one percent (n = 1344) of those were sagittal synostosis, and 23% (n = 756) were metopic synostosis. There was a significant increase of the absolute number as well as of the percentage of metopic synostosis over these years (regression analysis, P = 0.017, R2 = 0.578) as opposed to a nonsignificant increase in the percentage of sagittal synostosis (P > 0.05, R2 = 0.368). The most remarkable increase occurred around 2000-2001, with the average of metopics being 20.1% from 1997 to 2000 and 25.5% from 2001 to 2005 (independent t-test, P = 0.002). The sagittal synostosis showed a smaller and nonsignificant increase in the same years: from 39.9% in 1997-2000 leading up to 42.5% in 2001-2005 (independent t-test, P > 0.05). The number of metopic synostosis has significantly increased over the reviewed period in all of our units, both in absolute numbers as in comparison to the total number of craniosynostosis.

This paper describes the role of the displacement of bone centers, i.e., the tubers, in the pathogenesis of craniosynostosis. This displacement was studied in 54 patients with isolated or syndromic craniosynostosis in the form of CT scans as well as in two dry neonate skulls with Apert syndrome. For comparison, 49 fetal and 8 normal infant dry skulls were studied. Our investigation was restricted to the coronal and metopic sutures. The results showed a significantly more occipital localization of the frontal bone center and a more frontal localization of the parietal bone center at the side of a synostotic coronal suture in the isolated form as well as in Apert syndrome. In contrast, this was not the case in Crouzon syndrome, thus showing that these two syndromes have a different pathogenesis. For trigonocephaly, a more anteromedial localization of the frontal bone centers was found.

Object The aim of this study was to analyze the presence of beaten-copper patterns (BCPs) in children with craniosynostosis before 18 months of age and its association with their IQ at a later age. Methods The authors conducted a retrospective analysis of 538 cephalograms (obtained at a mean patient age of 1.16 years) from 95 patients. The BCP location and percentage of brain surface area covered were related to patient IQ scores obtained by the same psychologist using the Snijders–Oomen Nonverbal Intelligence Test–Revised, 51/2–17, and the Wechsler Preschool and Primary Scale of Intelligence–Revised. Results As much as 71.6% of patients presented with a BCP before 18 months of age (mean surface area of BCP 20.3%, 93% of patients presented with bilateral BCPs). The mean IQ was 95 ± 21.3 (range 50–136) at a mean patient age of 8.4 ± 2.59 years. There was a significant increase in the surface area covered by BCPs in the first 3 years of life (p < 0.001) and a significant difference in IQs between syndromic (30 cases, mean IQ 88.9) and nonsyndromic craniosynostosis cases (54 cases, mean IQ 98.9, p = 0.03). No significant correlation was found between IQ and the appearance of BCPs on presurgery radiographs (Pearson correlation coefficient = 0.143, p = 0.19) or their location (Spearman rank correlation coefficient = 0.091, p = 0.45). The BCPs appeared predominantly in the occipital region (41.1%). Conclusions Although the radiographic appearance of a BCP before the age of 18 months is an uncommon finding in healthy children, a craniosynostosis study group showed a preoperative BCP incidence of 71.6% and an increased incidence during the period of rapid brain expansion in the first 3 years of life. Note, however, that the presence of such a pattern had no significant long-term effect on patient intelligence levels.