ARUP; ISBN: 978-0-9562121-5-3 - CMBBE 2012 - Cardiff University

The geometry of bioimplant is saved in STL file and its detail internal scaffold
geometry is designed to provide optimal conditions for cells growing.
3.3 Aiding surgery
To follow the surgical scenario, the developed system supports surgeon by the tracking
of surgical tools using optical and electromagnetic navigation simultaneously (see fig.
5). The system applies optical system - Polaris Spectra and electromagnetic system-
Aurora from NDI, Canada.
The systems are working in parallel, which enables tracking when the line of sight is
disturbed or the level of electromagnetic disturbances prevents work of electromagnetic
navigation system.
The surgeon needs to mount a reference frame with optical and electromagnetic markers
to identify the real time position of patient head on the operation table. The surgical
tools need to be equipped with markers and calibrated to track them intraoperatively in
the real time.
Fig. 5. Computer aided resection
To track the tools and relate their position and orientation in the coordinate system of
DICOM CT/MRI dataset a crucial procedure is matching. The accuracy of
intraoperative system depends on the precise registration procedure. The Target
Registration Error describes the accuracy of the intraoperative system, since it is the
distance between corresponding points other than fiducial points after registration [2].
The system presents location of instruments and the value of the Target Registration
Error for control points selected by the user. The user decides how many landmarks are
used for the registration procedure. For the registration procedure the surgeon applies
the landmarks of face surface, bone and teeth.
The surgeon observes the visualization of saw cutting plane on the screen and the
designed cutting planes to fulfill the virtual surgical scenario.