Skull Expansion in Experimental Craniosynostosis

Bilateral coronal suture immobilization was performed in 9-day-old rabbits to simulate the brachycephaly deformity characteristic of coronal synostosis. Growth abnormalities were documented by serial radiographic cephalometry. A "corrective" linear craniectomy procedure was performed on the rabbits with an immobilized coronal suture at 60 days of age. The degree of amelioration of the induced abnormalities by the surgery in these animals was compared with a similar group of animals that had the same surgery plus supplemental implantation of a spring expansion device at the coronal suture craniectomy site. The mean marker separation at the coronal suture was significantly greater (5.61 mm +/- 0.52 SE versus 2.53 mm +/- 0.38 SE; p less than 0.05) following spring expander implantation than with linear craniectomy alone. Similarly, induced anterior cranial base shortening and distortion of craniofacial cephalometrics were more significantly improved by the additional use of the spring expansion device.