Multimodal noncontact tracking of surgical instruments

This paper describes the development and validation of the Inertial and Range-Enhanced Surgical (IRES) tracker-a novel, noncontact laparoscopic tracking system that may be used as an inexpensive alternative to optical and electromagnetic (EM) tracking systems for tracking surgical instruments. The system is based on the fusion of inertial, magnetic and distance sensing to generate real-time, 6-DOF pose data. Orientation is estimated using a Kalman-filtered attitude-heading reference system (AHRS) and restricted motion at the trocar provides a datum from which position information can be recovered. The IRES tracker was validated within a surgical training box. The results show that the IRES tracker achieves similar performance to an EM tracker with position error as low as 1.25 mm RMS and orientation error <;0.58° RMS along each axis. It also displayed greater precision and superior magnetic interference rejection capabilities. At a fraction of the cost of current laparoscopic tracking methods, the IRES tracking system is a suitable alternative for use in surgical training and skills assessment.