gms | German Medical Science

Objective: Our present understanding of cranial suture biology is based on morphological studies, mainly recruited from rats and birds. Normal and pathological growth patterns in humans have been derived from these observations containing non-proven assumptions. More detailed morphological analyzes of human sutures are still missing.

Methods: Histological investigations and microtomographic scans were performed in order to analyze five normal sutures at different time stages of the fusion process and five pathological synostotic sutures of different sites. Contrary to the customary micro-CT technique, a unique synchrotron radiation source with a monochromator could have been used generating an exceptionally high image resolution with 3D-reconstructions of the affected bones.

Results: Joint-like bony edges of the normal sutures are seen in the first month of life interlocking with increasing age. At the age of 12 months, thickness of the bone and suture width do not allow a further movement of the adjacent bony plates. Marked thickening of the diploe with ridging of the bone was found only in sagittal synostosis but not in coronal and lamdoid suture synostosis. On micro-CT all synostotic sutures were found to show only partial fusions. Furthermore the ultrastructural features of the non-fused sections showed no differences compared to the normal sutures.

Conclusions: In contrast previous assumptions, partial fusions in suture synostosis may be the rule and seem to express a dynamic fusion procedure progressing over time. Microtomographic analyzes of the non-fused sections in a synostosis were unremarkable when compared to normal sutures. Therefore an early surgical correction in the very first months of life may be advisable to achieve a complete normalization of the abnormal head shape with a minimal effort and less invasiveness.