CORONAL SUTURE PATHOLOGY AND SYNOSTOTIC PROGRESSION IN RABBITS WITH CONGENITAL CRANIOSYNOSTOSIS

The purpose of the present study was to describe coronal suture pathol ogy and cross sectional synostotic progression in an inbred strain of rabbits with congenital craniosynostosis, Calvaria from 102 perinatal rabbits (39 unaffected; 63 bilateral or unilateral synostosis) were co llected at fetal days 21 (n = 12), 25 (n = 20), 27 (n = 22), 30 (term) (n = 32), and 3 days post-term (n = 16) for gross morphologic and his tologic examination, Synostotic foci, the extent of relative bony brid ging, and suture morphology were evaluated qualitatively and quantitat ively. Of the 204 coronal sutures examined, 91 sutures were synostosed , and 113 were patent, All synostosed sutures showed similar foci by d ay 25, which originated as bony bridges in the middle of each suture o n the ectocortic surface, Bony bridging width increased significantly (p < .001) from day 25 through 3 days post-term, and was best describe d by a linear regression equation, Osteogenic front areas of synostose d sutures were up to 2.5 times greater than patent sutures in term fet uses, Findings demonstrate that coronal suture synostosis in the conge nital rabbit model (1) begins early during suture morphogenesis (befor e 25 days of gestation); (2) consistently radiates from a single focus corresponding to a normal interdigitating region (i,e., a high-tensio n environment); (3) varies in onset and rate as evidenced by low R(2) value between age and extent of bony bridging; and (4) is the result o f early hyperostosis of the osteogenic fronts and sutural agenesis. A number of possible pathogenetic mechanisms are discussed.