The Increase of Metopic Synostosis

Abstract

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.

An Epidemiological Study of Nonsyndromal Craniosynostoses

“…When the data were separated into 2 temporally distinct subgroups, in contrast to recent reports, 13 there was no difference in the frequencies of the major forms of synostosis during a period of (Table 4). In particular, the Fisher exact test shows no significant increase in the incidence of metopic synostosis relative to sagittal synostosis during this period (P G 0.4845).…”

“…12,13 A number of theories for this increase have been advanced, including a wide range of genetic and environmental factors, mechanical constraints, pharmaceutical effects, and social factors. 13,14 Another avenue that needs to be explored is the changed clinical environment in which these patients are treated. When the first epidemiological studies were published more than 40 years ago, craniofacial surgery, as a discipline, did not exist.…”

“…6Y13 The reasons for this increase are unclear at this point, with suggestions ranging from ascertainment bias to increased paternal age to maternal metabolic disorders. 13 At this point, however, there are no studies that provide data for any of these suggestions.…”

Nonsyndromic Craniosynostoses

“…In contrast to syndromic craniosynostosis with trigonocephaly, the nonsyndromic form tends to have a good prognosis [4,30]. Intriguingly, an increasing incidence of trigonocephaly (as well as other types of nonsyndromic craniosynostosis to a lesser degree) has recently been reported, the cause of which is unknown [31,32]. As in scaphocephaly, there is a distinct male preponderance, and approximately 5-6% of cases are familial [6,27].…”

A new quantitative image-based method for evaluation of bony temporal hollowing in metopic synostosis

“…Metopic synostosis; temporal hollowing; computed tomography images; MATLAB Background Premature closure of the metopic synostosis is the second most common type of craniosynostosis [1,2]. The disorder is characterised by a triangular forehead caused by restricted growth of the frontal bones, a compensatory increased interparietal width, a midline bony ridge, and ocular hypotelorism involving a reduced distance between the eyes and deformation of the orbital shape [3].…”