Stanford Prosthesis

Stanford Prosthesis This demo was done for Dr. Gail Lebovic at Stanford Hospital, in order to redesign a chest prothesis.

• left mouse button: rotates everything
• middle mouse button: zooms everything
• right mouse button: rotates only geometry or the rulers depending on which you select

This past summer work was done to combine real-time volume-rendering and geometry in order to help a surgeon, Dr. Gail Lebovic, at Stanford Hospital to redesign a chest prosthesis. The patient had been born with a sunken-in chest and usually what is done is they break and reset the ribs so that the rib cage will grow properly. The patient did not have this done but later in his adult life he wanted to have the defect corrected. A prosthesis was designed to fill in the gap and was manufactured by a company named Magan, one the largest manufacturers of silicone prosthesises. The methods of designing and manufacturing the prosthesis currently involves no computers and is basically done almost purely by human estimation and judgement. The prosthesis was placed into the patient and it was found to be too big even after the surgeon took it back out and shaved off some of the sides.

Dr. Lebovic came into contact with Carl Korobkin and told him about the case and then referred her to Chikai Ohazama, who wrote code to do volume rendering with imbedded geometry including tools such as geometry shaping and mensuration. The prosthesis mold was scanned by Cyberware, but due to the fact that the surgeon had shaved the original prosthesis and reduced the size so the scanned geometry no longer represented what was currently inside the patient. Therefore Chikai also wrote code to extract geometry from the CT data which was used to extract such things as the skin surface and the prosthesis existing within the patient.

The result of all this work allowed the surgeon to see the new prosthesis in context of the volumetric data and interactively design the prosthesis so that it would fit the patient better. The key element in this tool was real-time, the ability to make changes on the fly without any delay in response. If there were even a one second delay in response the tool would be too slow. This tool allows the surgeon to design a prosthesis in a relatively short period of time and test how it would fit in the patient before they do any surgery which in turn reduces the number of surgeries performed and therefore reduces medical costs.