The system is designed as an image-processing pipeline, in which the data is refined as it proceeds from the CT scanner to the operating room. The pipeline begins with a CT scan of the patient. The data are reformatted for use in UNIX-based workstations, and transferred from the Radiology Department. This processing is currently done in a laboratory, but in the future could be a separate service available to physicians. With the aid of interactive animated computer graphics, the surgeon can optimize the planned location of the bone cuts.
Cut placement is critical in both joint replacement and various corrective surgeries.
The biomechanical algorithms were developed at Queen's, and are based on a quasi-static analysis that minimizes total strain energy in the ligaments. In surgery, the operating-room coordinates must be registered with the CT coordinates in which the plan was computed. This is done by physically contacting the landmark regions with a high-precision coordinate measuring device. In the current system we use our patented locator implants, and a passive robotic arm, to increase the registration accuracy. We are actively developing new methods for performing and evaluating this crucial stage in computer-enhanced surgery.