Purpose: Accurate estimation of the position and orientation (pose) of
surgical instruments is crucial for delicate minimally invasive temporal bone
surgery. Current techniques lack in accuracy and/or line-of-sight constraints
(conventional tracking systems) or expose the patient to prohibitive ionizing
radiation (intra-operative CT). A possible solution is to capture the
instrument with a c-arm at irregular intervals and recover the pose from the
image.
Methods: i3PosNet infers the position and orientation of instruments from
images using a pose estimation network. Said framework considers localized
patches and outputs pseudo-landmarks. The pose is reconstructed from
pseudo-landmarks by geometric considerations.
Results: We show i3PosNet reaches errors less than 0.05mm. It outperforms
conventional image registration-based approaches reducing average and maximum
errors by at least two thirds. i3PosNet trained on synthetic images generalizes
to real x-rays without any further adaptation.
Conclusion: The translation of Deep Learning based methods to surgical
applications is difficult, because large representative datasets for training
and testing are not available. This work empirically shows sub-millimeter pose
estimation trained solely based on synthetic training data.Comment: Accepted at International journal of computer assisted radiology and
surgery pending publicatio
