Computer modeling approach for microsphere-packed bone scaffold

A computer modeling approach for constructing a three-dimensional microsphere-packed bone graft structure is presented. The modeling approach consists of both geometric and CAD-based computer modeling. The geometric model uses two extreme microsphere packing models (minimum-density packing and maximum-density packing) and a statistical packing model to determine the number of microspheres packed in a synthesized bone graft. The pore size of the packed internal porous structure is predicted, and a parametric study of the effect of microsphere diameter on the number of microspheres and pore size is conducted. Based on the results obtained from the geometric model, a CAD modeling approach for designing randomly microsphere-packed three-dimensional bone grafts was developed. The hierarchy of the CAD model and the steps for constructing a bone graft model are described, and application of the CAD-based bone graft model in internal structural examination, visualization, prediction and comparison with in vitro bone ingrowth is presented. q 2003 Elsevier Ltd. All rights reserved.