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  • Updated 05.25.2019
  • Released 10.01.1998
  • Expires For CME 05.25.2022

Craniosynostosis

Introduction

Overview

Craniosynostosis, the premature closure of cranial sutures, has been known to exist for centuries, but modern surgical management has only emerged and evolved over the past 100 years. Genetic findings have shed light in the pathophysiology of this disorder. In this article, the authors discuss the early descriptions of craniosynostosis, its molecular basis, and the evolution of its surgical treatment.

Key points

• Craniosynostosis is a condition characterized by the premature fusion of 1 or more of the cranial sutures.

• Its prevalence is 3 to 6 cases per 10,000 live births.

• It can be seen in normal individuals or as part of a multisystem syndrome.

• Genetic factors associated with it include mutations in EFNB1, EFNA4, MSX2, FGFR1-3, SHOC2, and TWIST1 genes.

• Surgical release of the affected suture is an effective way of correcting skull deformity and preventing mental retardation. Endoscopic techniques have been employed.

Historical note and terminology

Craniosynostosis is the premature fusion or abnormal development of 1 or more cranial sutures. Although the disorder was known in antiquity (there is speculation that the Athenian leader, Pericles, had sagittal synostosis) (26), Sommering observed in 1791 that skull growth occurs along cranial sutures and that growth failure at a suture results in skull deformity (107). In 1851 Virchow described various types of craniosynostosis and observed that normal growth occurs perpendicular to cranial sutures and that compensatory growth in craniosynostosis occurs parallel to the closed suture (119). Craniosynostosis occurring as part of dysgenetic syndromes was first reported by Apert, who described oxycephaly with syndactyly in 1906, and Crouzon who described craniofacial dysostosis in 1912. A large number of named syndromes followed; attribution of primacy for reporting remains a subject of dispute (20). Surgical treatment for craniosynostosis was pioneered in the 1890s by Lannelongue and Lane, both of whom performed strip craniectomy to remove a synostosed suture. Initially, little distinction was made between congenital, primary craniosynostosis and microcephaly (31). Surgery for affected infants and children resulted in high mortality and poor results. The popularity of surgical repair plummeted after a scathing critique by Jacobi in 1894 (54), but revived in the 1930s with more careful case selection and the more extensive procedures of Bauer (04) and King (62).

Nomenclature in craniosynostosis is complicated by a number of classifications. Causation divides the group into primary and secondary craniosynostosis. Primary synostosis is intrinsic to a disease process that closes a suture before or soon after birth, forcing the skull to grow in abnormal directions. Secondary craniosynostosis occurs when arrest of brain growth or metabolic diseases fail to keep an otherwise normal suture(s) patent. Causes of secondary craniosynostosis include microcephaly, shunted hydrocephalus, amniotic band syndrome, positional flattening or modeling of the calvarium and rickets. There are forms of craniosynostosis that are part of an inherited syndrome and associated with a host of congenital anomalies. A few of the more than 100 recognized syndromic synostoses (18) are listed in Table 1. These syndromes usually involve multiple sutures, especially the coronal. Nonsyndromic craniosynostosis, an isolated birth defect, is usually sporadic. Anatomical classification systems are based on the sites of affected sutures and resultant head shapes.

Table 1. Syndromic Craniosynostosis: Examples

Name

Associated findings

Inheritance

Crouzon disease

Midface hypoplasia, exorbitism, hypertelorism

Autosomal dominant

Apert syndrome

Same as Crouzon disease, plus syndactyly of all 4 limbs

Autosomal dominant

Pfeiffer syndrome

Same as Crouzon disease, plus beaked nose, broad thumbs and great toes, may be syndactyly

Autosomal dominant

Saethre-Chotzen syndrome

Facial asymmetry, strabismus, low hairline, variable syndactyly, normal thumbs and great toes

Autosomal dominant

Carpenter syndrome

Mental deficiency, short stature, obesity, variable syndactyly, heart and limb defects

Autosomal recessive

Cloverleaf skull

Can be associated with above syndromes, thanatophoric dysplasia

Autosomal dominant

Baller-Gerold syndrome

Radial, carpal, and digital aplasia

Autosomal recessive

Antley-Bixler syndrome

Same as Crouzon disease, plus choanal atresia and stenosis, multiple limb anomalies

Autosomal recessive

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