Frontal Bone Advancement and Compensatory Craniofacial Growth Changes in Rabbits with Experimental Coronal Suture Immobilization

Recent clinical advances in the surgical correction of coronal suture synostosis involve the overcorrection of a frontal bone segment to allow for unrestricted expansion of the developing neurocapsular matrix. However, the effects of such large-scale calvarial repositioning on subsequent brain mass growth trajectories and compensatory cranio-facial growth changes is unclear. This study was designed to investigate this relationship in an experimental rabbit model of bilateral coronal suture synostosis. Amalgam markers were placed across the frontonasal, coronal, and anterior lambdoid sutures in thirty-one 1.5-week-old rabbits. Twenty-one animals underwent bilateral coronal suture immobilization using methyl-methacrylate. Ten animals were left untreated and served as sham controls. At 6 weeks of age, the coronal suture was released by frontal bone craniotomy or frontal bone craniotomy with a 6-mm frontal bone advancement. Lateral head radiographs were taken at 1.5, 6, 7, 9, 12, and 18 weeks of age. Results revealed that by 6 weeks of age, animals with coronal suture immobilization exhibited growth disturbances across the various sutures resulting in altered craniofacial and cranial vault shape compared to control animals. Following coronal suture release, animals that underwent craniotomy showed rapid restenosis, which resulted in significantly altered cranial vault shape and cranial orthocephalization by 18 weeks of age. Animals that underwent frontal bone advancement exhibited normal overall craniofacial growth by 18 weeks of age compared with control animals but did exhibit regional compensatory growth disturbances at the frontonasal and anterior lambdoid sutures, possibly related to neural tissue distension.(ABSTRACT TRUNCATED AT 250 WORDS)