Editor in Chief
Craniosynostosis is the premature fusion of one or more sutures of a child’s skull. It can be considered primary or secondary on the basis of the time of suture closure and its etiology. Virchow’s law states that the skull normally grows perpendicular to the open suture, thereby giving the child a characteristic skull that is narrow bitemporally and wider in the parietal region bilaterally (29). When a suture is closed, the brain forces the skull into compensatory growth patterns. The resulting skull shape is determined by which suture is closed (14, 29). Primary craniosynostosis is an in-utero fusion of suture. Current theory suggests an interaction between underlying dura and abnormal osteoblasts at the suture front. These osteoblasts appear to proliferate more rapidly and have an increased response to growth factors compared to normal osteoblasts (13, 37). Transcription factors such as TWIST1 have been implicated in normal and abnormal sutural closure, and growth factor receptor mutations are observed (13, 26). However, genetic and chromosomal anomalies are more common in syndromic synostosis ( 26, 30, 50). Secondary craniosynostosis is a suture closure due to an exogenous factor such as rickets, vitamin D-resistant rickets, hypophosphatemia, hyperthyroidism, polycythemia vera, sickle cell anemia, medications (chlorpheniramine, nitrofurantoin, methotrexate, valproic acid), Hurler’s and Morquio’s syndromes, and overly shunted hydrocephalus (12, 20, 48).
- Four types of nonsyndromic craniosynostosis: There are four patterns of craniosynostosis, depending on which sutures (sagittal, coronal, metopic, or lambdoid) are prematurely fused, with each having specific appearances and treatment plans.
- Elevated ICP or cosmetic deformities may be indications for surgery: Surgical intervention may be required in the face of elevated ICP or cosmetic deformities (46). A recent neurocognitive paper suggests the occurrence of some developmental delays in children with isolated single suture fusions. Close follow-up in the craniofacial clinic or with neurodevelopmental testing may be in order (43).
- Age-specific repair: Minimally invasive procedures can be considered for infants younger than 3 months of age, while cranial remodeling is required for children at older ages.