|Institution:||University of Pittsburgh|
|Full text PDF:||http://d-scholarship.pitt.edu/32042/1/deolhs_etd2017.pdf;http://d-scholarship.pitt.edu/32042/|
Delayed-onset craniosynostosis has been reported in the human clinical literature and may represent part of the expanded phenotype of craniosynostosis. Delayed-onset synostosis (DOS) is also an integral part of the phenotypic spectrum in an inbred rabbit strain of craniosynostosis. The purpose of the present study was to qualitatively and quantitatively describe the perisynostotic events in the coronal sutures of rabbits with delay-onset coronal suture synostosis compared to age matched, wild-type control rabbits. Coronal sutures from 80 rabbits (39 normal wild-type controls and 41 DOS) were collected for gross morphological and histological examination. Ages ranged from term (day 0) through 88 days of age. The sutures were harvested, formalin fixed, paraffin embedded, and stained with alizarin red for gross light microscopic analysis. Qualitative results showed that by 25 days of age a dramatic thickening of the sutural ligament, an increase in the amount of bone in the osteogenic fronts, and an increase in the frequency of bony bridges between the frontal and parietal bones in rabbits with DOS compared to age matched, wild-type controls. No statistical significant differences in mean suture width or total suture area between the groups at the interdigitating zone were recorded at any age and cortical level (p> 0.05). At a region of the coronal suture closer to the midline, deemed the medial zone, a significant difference was found in mean suture width between groups at 88 day in age group at the ectocortical suture surface (p <.05); additionally, significant differences in mean suture area between the groups were recorded at age 25 and 88 (p <.05). A significant difference bony bridging frequency between the interdigitating zone and medial zone of DOS sutures was observed at the 45 day age group. The results of the 6X2 (age by group) two-way ANOVA indicate significant interaction at various cortical levels as well as total suture area at the interdigitating and medial zone (p < 0.05). Results suggest that bony bridging and sutural ligament thickening occurs much earlier than coronal suture growth cessation in DOS rabbits and that these factors may limit subsequent sutural growth in an additive effect.