POSTNATAL CHANGES IN THE CRANIAL BASE IN RABBITS WITH CONGENITAL CORONAL SUTURE SYNOSTOSIS

Cranial base abnormalities are a common correlate of human craniosynos tosis, although controversy exists as to whether they are primary malf ormations or secondary deformities. The current study assesses longitu dinal cranial base growth and shape changes in rabbits with congenital coronal suture (CS) synostosis. Data were collected from 96 New Zeala nd White rabbits: 21 with complete bilateral or unilateral CS synostos is; 33 with partial CS synostosis; and 42 unaffected, ''control'' litt er 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 o f age, rabbits with complete synostosis had significantly (P < 0.05) s hortened anterior cranial bases, orthocephalic cranial base angles, an d acute, dysmorphic cribriform plate triangular shapes compared to the two other groups. Some significant differences persisted through 18 w eeks of age. No significant differences were noted between partially s ynostosed and normal rabbits at any time period. If partial synostosis represents a continuum of the craniosynostotic phenotype, then the cr aniosynostosis may be seen as the primary deformity in this model and the cranial base abnormalaties as secondary, deformational changes. Ho wever, 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 mo deling cases of familial, human non-syndromic coronal suture synostose s.