Page 439 - Biomedical Engineering and Design Handbook Volume 2, Applications

COMPUTER-INTEGRATED SURGERY AND MEDICAL ROBOTICS 417

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FIGURE 14.18 Virtual endoscopy: (a) three-dimensional reconstruction of structure to be viewed and (b) view from the inside fly-through.
(Reproduced from Ref. 98.)

These applications fit naturally within the context of surgical CAD/CAM systems. For example,
Fig. 14.19 shows the information flow for the current ROBODOC implementation. The information
flow in the CASPAR system is very similar. CT images of the patient’s bones are read into a plan-
ning workstation and a simple segmentation method is used to produce an accurate surface model of
key anatomical areas. After some key anatomical measurements are made from the images, the sur-
geon selects an implant design from a library and determines its desired placement in the patient by
manipulating a CAD model of the implant with respect to selected mutually orthogonal cross sections
through the CT data volume. The planning workstation computes a cutter trajectory relative to CT
coordinates and all of the planning information is written to a magnetic tape along with the patient
images and model.
In the operating room, robotic hip replacement surgery proceeds much as manual surgery until
after the head of the femur (for the case of primary hip surgery) or failing implant (for revision

FIGURE 14.19 Information flow in a typical orthopedic robotic
system (in this case, the ISS ROBODOC system).