M. Kaus et al., TECHNICAL ACCURACY OF A NEURONAVIGATION SYSTEM MEASURED WITH A HIGH-PRECISION MECHANICAL MICROMANIPULATOR, Neurosurgery, 41(6), 1997, pp. 1431-1436
OBJECTIVE: This study was designed to determine and evaluate the diffe
rent system-inherent sources of erroneous target localization of a lig
ht-emitting diode (LED)-based neuronavigation system (StealthStatisn,
Stealth Technologies, Boulder, CO). METHODS: The localization accuracy
was estimated by applying a high-precision mechanical micromanipulato
r to move and exactly locate (+/-0.1 mu m) the pointer at multiple pos
itions 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 dete
cted was 0.55 +/- 0.29 mm, with the z direction (distance to the camer
a array) being the most erroneous coordinate. Minimum localization err
or was found at a distance of 1400 mm from the central camera (optimal
measurement position). Additional error due to 1) mechanical vibratio
ns 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 coor
dinates of at least +/-0.12 mm were detected, leading to a total techn
ical error of 0.55 +/- 0.64 mm. CONCLUSIONS: Based on this technical a
ccuracy analysis, a set of handling recommendations is proposed, leadi
ng to an improved localization accuracy. The localization error could
be reduced by 0.3 +/- 0.15 mm by correct camera positioning (1400 mm d
istance) plus 0.15 mm by vibration-eliminating fixation of the camera.
Correct handling of the probe during the operation may improve the ac
curacy by up to 0.1 mm.