Use of scanning electron microscopy in the evaluation of craniosynostosis.

The cause of craniosynostosis continues to elude researchers. Although several studies have looked at the ultrastructure of normal suture closure, no previous studies have examined the microarchitecture of the synostotic suture. Our goal was to assess the scanning electron microscope (SEM) as a viable and useful tool in examining craniosynostosis. Our hypothesis is that the SEM is a powerful analytical tool that can evaluate nonsynostotic, partial synostotic, and complete synostotic cranial sutures. We analyzed the cranial suture of 3 human infants with nonsyndromic sagittal craniosynostosis. The specimens were separated into three groups, which included regions of partial and complete synostosis and a region of open suture. Histological examination provided cellular and tissue data about craniosynostosis, whereas the SEM provided detailed information regarding the trabecular microarchitecture of the synostosed suture. The SEM produced quality images of complete and partially synostotic sutures and open sutures. At low magnification, the SEM characterized the general bony microarchitecture of cranial sutures in a manner different from, but complementary to, standard histological sections. At higher magnification, the SEM allowed us a look at the cellular population of craniosynostotic sutures in a way that surpasses standard light microscopy. The SEM is an excellent tool for the study of craniosynostosis and has proved invaluable in our ability to evaluate the microarchitecture and cellular population of the fusing suture. We believe we have proven our hypothesis by demonstrating the SEM to be a powerful analytical tool that can evaluate nonsynostotic, partial synostotic, and complete synostotic cranial sutures.