Three-dimensional virtual-reality surgical planning and soft-tissue prediction for orthognathic surgery.

Complex maxillofacial malformations continue to present challenges in analysis and correction beyond modern technology. The purpose of this paper is to present a virtual-reality workbench for surgeons to perform virtual orthognathic surgical planning and soft-tissue prediction in three dimensions. A resulting surgical planning system, i.e., three-dimensional virtual-reality surgical-planning and soft-tissue prediction for orthognathic surgery, consists of four major stages: computed tomography (CT) data post-processing and reconstruction, three-dimensional (3-D) color facial soft-tissue model generation, virtual surgical planning and simulation, soft-tissue-change preoperative prediction. The surgical planning and simulation are based on a 3-D CT reconstructed bone model, whereas the soft-tissue prediction is based on color texture-mapped and individualized facial soft-tissue model. Our approach is able to provide a quantitative osteotomy-simulated bone model and prediction of postoperative appearance with photorealistic quality. The prediction appearance can be visualized from any arbitrary viewing point using a low-cost personal-computer-based system. This cost-effective solution can be easily adopted in any hospital for daily use.

Computer-assisted three-dimensional surgical planning and simulation: 3D virtual osteotomy.

A computer-assisted three-dimensional virtual osteotomy system for orthognathic surgery (CAVOS) is presented. The virtual reality workbench is used for surgical planning. The surgeon immerses in a virtual reality environment with stereo eyewear, holds a virtual "scalpel" (3D Mouse) and operates on a "real" patient (3D visualization) to obtain pre-surgical prediction (3D bony segment movements). Virtual surgery on a computer-generated 3D head model is simulated and can be visualized from any arbitrary viewing point in a personal computer system.

A new endoillumination infusion cannula for pars plana vitrectomy.

A new endoillumination infusion cannula has been developed that allows for wide field illumination of the retina during pars plana vitrectomy surgery. This frees the surgeon from having to use one of the intravitreal probes for endoillumination when using the bimanual technique in pars plana vitrectomy. This innovative endoillumination source also can be used with indirect ophthalmoscopy, at surgery, avoiding the glare generated by the indirect ophthalmoscope's light beam interacting with the corneal surface and the condensing lens surfaces.

An improved endoillumination probe for pars plana vitrectomy.

A newly modified endoillumination probe using the Ocutome handle has been developed that has 2.5 times more total light output and over four times more light intensity than the conventional endoillumination probe. The new probe is particularly useful in situations where there is extremely dense vitreous hemorrhage and when one requires additional light for 16-mm cinematography.

Coupling of rigid to flexible imaging multifibers.

By magnifying the high-quality image produced by a rigid miniature endoscope onto a large flexible multifiber, an instrument has been developed which provides both high resolution and flexibility. It is shown theoretically, and verified experimentally, that the MTF of a system of coupled multifibers is the product of the individual MTFs. Measurements show that the coupled instruments outperform state-of-the-art all-flexible systems. The technique should greatly facilitate observation, display, and photography in percutaneous endoscopy and in a variety of industrial applications.