TrEndo, a device for tracking minimally invasive surgical instruments in training setups

A novel, four degrees of freedom, low-cost device for tracking minimally invasive surgical instruments (MIS) in training setups was developed. This device consists of a gimbal mechanism with three optical computer mouse sensors. The gimbal guides the MIS instrument, while optical sensors measure the movements of the instrument. To test the feasibility of using optical mouse sensors to track MIS instruments, the accuracy of these sensors was tested depending on three conditions: distance between lens and object, velocity of movements, and surface characteristics. The results of this study were used for developing a prototype-TrEndo. Tests performed on TrEndo show that the smallest movement that can be recognized by sensors is 0.06 mm for translation and 1.27 degrees for rotation of the MIS instrument around its axis. The smallest recognized angle for rotation around incision point is 0.23 degrees. The accuracy of TrEndo is higher than 95%, and therefore allows tracking the movements of the MIS instrument. (C) 2005 Elsevier B.V. All rights reserved.