Pre-surgical CT/FEA for craniofacial distraction: I. Methodology, development, and validation of the cranial finite element model

Recently, surgeons have begun to treat serious congenital craniofacial defo rmities including craniosynostoses with mechanical devices that gradually d istract the skull. As a prospective means of treatment planning for such co mplex deformities, FE models derived from routine preoperative CT scans (CT /FEA) would provide ideal patient specific engineering analyses. The purpos e of this study was to assess the dimensional and predictive accuracy of th e CT/FEA process through the development of a 3D model of a dry human calva rium subjected to two-point distraction ex vivo. Comparative skull measurem ents revealed that CT/FEA construction error did not exceed 1% for transcra nial dimensions, and the thickness error did not exceed 8.66% or 0.31 mm. C T/FEA strain predictions for the central region of the skull, between the d istraction posts, were not statistically different from homologous gage val ues at P < 0.05. Peripherally, however, the strain fields were less well be haved and the FE predictions showed only general qualitative agreement with gage recordings. (C) 1998 IPEM. Published by Elsevier Science Ltd. ALI rig hts reserved.