Related Experiment Video
Updated: Jun 15, 2026
10:25
Technical Approach for Infrared Tracking for Soft Tissue Navigation with a Holographic Head-Mounted Display and Preclinical Validation
Published on: September 2, 2025
Assessment of optical localizer accuracy for computer aided surgery systems
Robert Elfring1, Matías de la Fuente, Klaus Radermacher
1Chair of Medical Engineering, Helmholtz-Institute for Biomedical Engineering, RWTH Aachen University, Aachen, Germany. elfring@hia.rwth-aachen.de
Summary
This study evaluated the accuracy of three optical localizer systems for computer-aided surgery. Active systems, Stryker Navigation and Polaris Spectra, demonstrated superior precision compared to passive systems, with lower tracking errors in clinical simulations.
Area of Science:
- Medical technology
- Surgical navigation
- Computer-aided surgery
Background:
- Accurate localization of surgical tools is crucial for computer-aided surgery.
- Optical tracking is widely used but its accuracy requires ongoing evaluation.
- Existing systems vary in performance, necessitating comparative studies.
Purpose of the Study:
- To critically assess and compare the accuracy of three optical localizer systems: NDI Polaris P4, NDI Polaris Spectra (active and passive modes), and Stryker Navigation System II camera.
- To evaluate system performance under static conditions and within a defined measurement volume.
- To estimate expected tracking errors in typical clinical setups through simulation.
Main Methods:
- Static tests were conducted to observe system warm-up behavior and accuracy shifts.
- Volumetric measurement protocols using a coordinate measurement machine determined intrinsic localizer accuracy for markers and tools.
- Length Measurement Error (LME) was calculated at 35 test lengths to assess relative distance error.
- Simulations estimated tracking errors for different tool configurations in clinical scenarios.
Main Results:
- The NDI Polaris P4 exhibited significant warm-up behavior, affecting accuracy within 42 minutes.
- Active systems (Stryker Navigation: 0.058 +/- 0.033 mm; Polaris Spectra active: 0.089 +/- 0.061 mm) showed higher trueness than passive systems.
- Polaris Spectra passive mode achieved 0.170 +/- 0.090 mm trueness, while Polaris P4 had the lowest trueness (0.272 +/- 0.394 mm) with more outliers.
- Simulated clinical tracking errors were: Stryker Navigation (0.22 mm), Polaris Spectra active (0.33 mm), Polaris Spectra passive (0.64 mm), and Polaris P4 (1.02 mm).
Conclusions:
- Active optical localizer systems provide superior accuracy for surgical navigation compared to passive systems.
- The Stryker Navigation System II camera and Polaris Spectra (active mode) are recommended for applications requiring high precision.
- System warm-up and marker configuration significantly influence localization accuracy in clinical practice.
