How precise is navigation for minimally invasive surgery?

Infra-red measurement systems are an established facet of operative procedures using surgical navigation, yet questions remain regarding their accuracy and everyday suitability. The importance of these systems has grown with the increasing popularity of minimally invasive procedures, which are associated with a reduction in operative field visibility. Even though these measurement systems are reliable and accurate, residual errors are still present and impact the overall success rate of surgical navigation. We performed empirical experiments to evaluate the effect of the error of digitization using a navigated probe on the accuracy of the predicted position and orientation of an acetabular cup. An accuracy of approximately 0.3 mm resulted in a potential error of 1.5 mm in predicted cup position and 0.2 degrees in inclination. It is possible to estimate expected accuracy through the use of statistical methods and, as a result, to optimise procedures and test methods using this knowledge.