Target Registration Errors in Navigation-assisted Mandibular Surgery According to the Tracking Methods and the Type of Markers

Abstract

Background: This study was conducted to evaluate the accuracy of navigation process according to the type of tracking methods and registration markers. The target registration errors (TREs) were measured at seven anatomical landmarks of the mandible for evaluation. Methods: Four different experiments were performed to obtain the TREs using two different tracking methods, the optical tracker (Polaris) and the electromagnetic (EM) tracker (Aurora), and two different types of registration markers, invasive and noninvasive markers. All comparisons of TREs were statistically analyzed using SPSS and Python-based statistical package (Pingouin). Results: The average TRE values obtained from the four different experiments were as follows: 1) 0.85 mm using invasive marker and Aurora, 2) 1.06 mm using invasive marker and Polaris, 3) 1.43 mm using noninvasive marker and Aurora, and 4) 1.57 mm using noninvasive marker and Polaris. All comparisons among the type of markers and the seven anatomical landmarks revealed statistically significant differences, except for the type of tracking system. Although the comparison between the modality of the tracking system showed no significant differences, the EM-based approach consistently demonstrated better performances than the optical type in all comparisons. Conclusions: This study demonstrates that, irrespective of the tracking modality, the invasive marker is a better choice in terms of accuracy. When using the noninvasive marker, it is important to consider the increased TREs. In the present study, the noninvasive marker caused a maximum increment of TREs of approximately 0.81 mm compared with the invasive marker. Furthermore, EM-based tracking using an invasive marker may result in the best accuracy for the mandible.

An improved method for assessing the technical accuracy of optical tracking systems for orthopaedic surgical navigation

“…To perform these measurements, often the tip of a tracked pointer is used. Many studies use the terminology TRE while evaluating the TTRE as defined by Min et al., 14,15,17,24 which may potentially lead to confusion. In the remainder of this manuscript, TRE will be reserved for the error of the pointer registration itself and TTRE will be used to describe errors resulting from the measurements of points in the surgical space with a calibrated pointer 23 .…”