Recent advances in trigonocephaly.

INTRODUCTION: The aim of this review was to report on recent advances in trigonocephaly since the last report on craniosynostosis published in 2006. MATERIAL AND METHODS: The review was conducted in accordance with the PRISMA guidelines. Research focused on four main topics: epidemiology, neurodevelopmental disorders, genetics and surgical techniques. RESULTS: Forty reports were included. The prevalence of trigonocephaly increased during the last two decades both in Europe and in the United States, but no clear contributing factors have yet been identified. Neurodevelopmental disorders are frequent in syndromic trigonocephaly and not particularly rare in non-syndromic cases (up to 34%). Developmental retardation (speech, motor or global) was almost always present in children exposed to valproic acid. Chromosomal abnormalities described in metopic synostosis comprised deletion of chromosome 11q24, deletion or trisomy of 9p and deletion of 7p, deletions of 3q, 13q, 12pter, 22q11, and duplication of 15q25. SMAD6 mutations should be systematically screened for in familial cases. Recent advances in surgical techniques have mainly concerned endoscopic-assisted procedures, as they significantly reduce perioperative morbidity. CONCLUSIONS: Neurosurgeons, maxillofacial and plastic surgeons will be increasingly concerned with trigonocephaly because of the increase in prevalence observed over the last two decades. Cytogenetic alterations are probably underestimated in this craniosynostosis, considering the high rate of neurodevelopmental retardation compared to other single-suture synostoses. Genetic counselling is therefore more and more effective in this pathology. An objective method to evaluate the cosmetic results of both endoscopic and open surgeries is necessary, as some under-corrections have been reported with minimally invasive surgery.