The antenatal diagnosis of isolated sagittal craniosynostosis

Abstract

Introduction Isolated sagittal craniosynostosis is the most common premature sutural fusion, but is rarely diagnosed antenatally. There are now a number of reports in the literature describing delivery issues in infants later diagnosed with sagittal synostosis(1-6). The aim of this study was to investigate whether delivery issues are more common in children diagnosed with sagittal synostosis, and identify markers at antenatal ultrasound that could help diagnose the condition before birth. Methods The antenatal ultrasound images of children born in South Australia and the Northern Territory after 1/1/2000 who have diagnosed with isolated sagittal synostosis were compared with antenatal imaging from normal infants without any craniofacial defects. The delivery details from the affected children were also compared to the population delivery data over an extended time period. Results There was a statistically significantly higher rate of malpresentation and surgical delivery in the sagittal synostosis population. There no significant difference in the cephalic index between the 2 groups at mid trimester morphology scanning. The ultrasound scans showed progressive scaphocephaly during the second half of pregnancy in the affected children while the control population showed minimal change in head shape with a slight tendency towards brachycephaly. Conclusions 1. Isolated sagittal synostosis typically begins in the second half of pregnancy, and is not detectable antenatally at the mid trimester morphology scan. 2. It is possible to diagnose sagittal synostosis in the third trimester by noting a progressive decrease in the fetal cephalic index, which should provoke 3D ultrasound scanning of the fetal skull to examine the sagittal suture. 3. There is a clear relationship between the presence of sagittal craniosynostosis and breech presentation at delivery in affected fetuses, with a marked increase in the rate surgical deliveries in this group of infants.