Neurocapsular growth is highly heritable and determines neurocranial form. Although craniosynostosis alters brain growth direction, resulting in compensatory changes in the neurocranium, it is believed that such compensations occur without reduction in intracranial volume. This hypothesis was tested in a rabbit model with nonsyndromic, familial coronal suture synostosis. Skulls of 56 rabbits (20 normals, 20 with delayed onset synostosis, and 16 with complete synostosis) were scanned using three-dimensional computed tomography at 6 and 18 weeks of age. Intracranial contents were reconstructed, and indirect intracranial volume was calculated. Qualitatively, re-formations of intracranial contents from completely synostosed rabbit skulls exhibited the typical “copper beaten” morphology. Quantitatively, intracranial volume was significantly (p < 0.05) reduced in rabbit skulls with complete synostosis compared with both control rabbit skulls and rabbit skulls with delayed onset synostosis at 6 weeks by 11 percent and 14 percent, respectively). By 18 weeks, intracranial volume in rabbit skulls with synostosis was significantly (p < 0.05) reduced (by 12 percent in complete synostosis and 8 percent in delayed onset synostosis) compared with normal rabbits. Results suggest that in rabbits with uncorrected craniosynostosis, compensatory changes in the neurocranium were not adequate to allow normal expansion of the neurocapsular matrix. Further research is needed to determine whether reduction in intracranial volume was a result of neural tissue deficiency or cerebrospinal fluid (i.e., ventricular or subarachnoid) space compression in this model. (Plast. Reconstr. Surg. 100: 1121, 1997.)
Pittsburgh, Pa., and Slippery Rock, Pa.
From the Cleft Palate-Craniofacial Center, the Division of Plastic Surgery, and the Departments of Anatomy, Histology, Anthropology, and Orthodontics at the University of Pittsburgh; the School of Physical Therapy at Slippery Rock University; the Department of Radiology at the University of Pittsburgh Medical Center; and the Division of Pediatric Plastic Surgery, Department of Radiology at Children's Hospital of Pittsburgh. Received for publication July 2, 1996; revised April 4, 1997.
Presented, in part, at the Annual Meetings of the American Association for Dental Research (IADR). in San Francisco, Calif., in March of 1996, at the American Cleft Palate-Graniofacial Association meeting. in San Diego, Calif., in April of 1996, and at the American Association of Physical Anthropologists meeting, in Durham, N.C., in April of 1996.
Mark P. Mooney, Ph.D.
Department of Anatomy and Histology, 631 Salk Hall
University of Pittsburgh
Pittsburgh, Pa. 15261