Technical accuracy of a neuronavigation system measured with a high-precision mechanical micromanipulator.
OBJECTIVE
This study was designed to determine and evaluate the different system-inherent sources of erroneous target localization of a light-emitting diode (LED)-based neuronavigation system (StealthStation, Stealth Technologies, Boulder, CO).


METHODS
The localization accuracy was estimated by applying a high-precision mechanical micromanipulator to move and exactly locate (+/- 0.1 micron) the pointer at multiple positions in the physical three-dimensional space. The localization error was evaluated by calculating the spatial distance between the (known) LED positions and the LED coordinates measured by the neuronavigator. The results are based on a study of approximately 280,000 independent coordinate measurements.


RESULTS
The maximum localization error detected was 0.55 +/- 0.29 mm, with the z direction (distance to the camera array) being the most erroneous coordinate. Minimum localization error was found at a distance of 1400 mm from the central camera (optimal measurement position). Additional error due to 1) mechanical vibrations of the camera tripod (+/- 0.15 mm) and the reference frame (+/- 0.08 mm) and 2) extrapolation of the pointer tip position from the LED coordinates of at least +/- 0.12 mm were detected, leading to a total technical error of 0.55 +/- 0.64 mm.


CONCLUSIONS
Based on this technical accuracy analysis, a set of handling recommendations is proposed, leading to an improved localization accuracy. The localization error could be reduced by 0.3 +/- 0.15 mm by correct camera positioning (1400 mm distance) plus 0.15 mm by vibration-eliminating fixation of the camera. Correct handling of the probe during the operation may improve the accuracy by up to 0.1 mm.
Kaus
M
M
Neurochirurgische Klinik, University of Erlangen-Nümberg, Germany.
Steinmeier
R
R
Sporer
T
T
Ganslandt
O
O
Fahlbusch
R
R
D005069:Evaluation Studies as Topic; D007091:Image Processing, Computer-Assisted / Q000295:instrumentation / Q000592:standards*; D008846:Micromanipulation / Q000295:instrumentation*; D009493:Neurosurgery / Q000379:methods*; D013813:Therapy, Computer-Assisted / Q000295:instrumentation; D014732:Vibration