Computer system for craniofacial surgical planning based on CT images.

A system for craniofacial surgical planning utilizing stacks of 2-D tomographic images is described. The four parts of the system are image generation, 2-D surgical planning, 3-D plan confirmation, and rough prediction of face shape after an operation. The four parts are combined to provide a useful surgical planning system. Because a gradient shading technique is used for generating 3-D images, the bumpy shape of the voxel (volume element for 3-D objects) sometimes obscures the essential shape of the displayed objects. To smooth undesirable bumps without losing the essential object shape, 2-D filtering is applied. Arbitrary bone blocks can be specified and moved interactively with a graphic terminal to any derived location to aid surgical planning. The chosen plan can be confirmed by observing computer-generated 3-D images from arbitrary directions since the process necessary to generate a 3-D image for any one direction should be adequate for all directions. Postoperative face-shape prediction is available for evaluating the operation plan at the last stage of the planning sequence.