Relevance of correction for rotational targeting error in functional neurosurgery

Figures & data

Figure 1. Rotations of the head (AP-PC line) relative to the stereotactic frame may be described by the nautical terms pitch, yaw and roll. (a) Yaw angle; (b) Roll angle; (c) Pitch angle.

Table I.  Differences between results obtained with 2- and 3-point correction algorithms.

Target	Mean difference ± standard deviation	Maximum difference
xSTN	0.10 ± 0.07	0.29
ySTN	0.03 ± 0.04	0.13
zSTN	0.52 ± 0.49	2.80
xGPI	0.13 ± 0.08	0.41
yGPI	0.07 ± 0.09	0.41
zGPI	0.74 ± 0.35	1.43
xVim	0.04 ± 0.03	0.12
yVim	0.05 ± 0.05	0.16
zVim	0.48 ± 0.24	0.94

Mean difference = mean of the absolute values of differences between the calculations for rotational correction according to the 2-point- and 3-point-based algorithms. “x” represents the deviation in the lateral direction, “y” the deviation in antero-posterior, and “z” the deviation in the cranio-caudal direction.

Figure 2. Differences between 3-point-based and 2-point-based corrections depending on (a) the yaw angle, (b) the roll angle, and (c) the pitch angle.