Introduction:
To improve cochlear surgery, a high precision micro-stereotactic framework for drilling a minimally invasive approach from the mastoid surface via the facial recess to the round window niche will be developed. The System consists of two parts. A reusable base platform is used to incorporate fixation elements for rigid attachment of the system to the patient's head and includes the registration markers, therefore, must be mounted prior to imaging in the retromastoid region. After 3D-scan (CT or DVT) of the patient, a second platform called “Jig” can be fabricated, consisting of the patient-specific dill trajectory. Thereby, guidance of the surgical instruments might be feasible according to the individual patient anatomy.
Methods:
In order to investigate the precision of the system, 20 individually calculated holes with different drill angles were drilled into the Jig by a Stewart-Gough-Plattform (Hexapod) and the extended trajectories (60 mm in depth) were measured with a coordinate measuring machine.
Results:
The accuracy of the finished device was 0.11 mm ± 0.04 mm. Inaccuracies caused by preceding and subsequent errors, e.g. segmentation or drilling system, are not included in this study.
Conclusion:
Good accuracy results were achieved in all tests. Since the system offers further benefits like real-time Jig fabrication without delay, can be easily handled by the surgeon, no additional staff and no further sterilization is required, we aim, that the presented RoboJig system might be successfully usable in future studies for minimal invasive cochlear surgery.
