Postnatal changes in the cranial base in rabbits with congenital coronal suture synostosis

Cranial base abnormalities are a common correlate of human craniosynostosis, although controversy exists as to whether they are primary malformations or secondary deformities. The current study assesses longitudinal cranial base growth and shape changes in rabbits with congenital coronal suture (CS) synostosis. Data were collected from 96 New Zealand White rabbits: 21 with complete bilateral or unilateral CS synostosis; 33 with partial CS synostosis; and 42 unaffected, "control" litter mates. Serial radiographs were taken at 1.5, 6, 12, and 18 weeks of age. Linear, angular, and shape measurements of the cranial base were compared among the three groups. Results revealed that at 1.5 weeks of age, rabbits with complete synostosis had significantly (P < 0.05) shortened anterior cranial bases, orthocephalic cranial base angeles, and acute, dysmorphic cribriform plate triangular shapes compared to the two other groups. Some significant differences persisted through 18 weeks of age. No significant differences were noted between partially synostosed and normal rabbits at any time period. If partial synostosis represents a continuum of the craniosynostotic phenotype, then the craniosynostosis may be seen as the primary deformity in this model and the cranial base abnormalaties as secondary, deformational changes. However, fetal data are still needed to more clearly delineate the role of the cranial base in this congenital rabbit model. Results reiterate the appropriateness and continued development of these rabbits for modeling cases of familial, human non-syndromic coronal suture synostoses.