Effect of registration mode on neuronavigation precision: an exploration of the role of random error

Figures & data

Figure 1. The three different registration modes used in the study: (a) the auto-registration mask; (b) scalp fiducials; and (c) bone fiducials. In (d) the pointer is seen touching one of the external targets.

Figure 2. (a) Endoscopic view showing one of the internal targets being placed using endoscope guidance. (b) Endoscopic view showing the final location of the implanted internal targets (the planum and clivus).

Table I.  Comparison of fiducial (or surface) registration error as calculated by the neuronavigation system using different registration modalities. The associated coefficient of variation is also shown.

Mode of registration	Mean accuracy (±SD)	Coefficient of variation
Bone fiducials	1.96 mm (±1.28)	27.296
Adhesive fiducials	3.12 mm (±1.63)	22.46
Mask	3.20 mm (±1.40)	16.32

Table II.  Operational accuracy of the navigation system in reaching targets using different registration modalities, and the associated coefficient of variation.

	Targets
	External anterior		External posterior		Internal anterior		Internal posterior
Mode of registration	Mean accuracy (±SD) (mm)	Coefficient of variation (CV) (%)	Mean accuracy (±SD) (mm)	Coefficient of variation (CV) (%)	Mean accuracy (±SD) (mm)	Coefficient of variation (CV) (%)	Mean accuracy (±SD) (mm)	Coefficient of variation (CV) (%)
Bone fiducials	1.96 (1.28)	65.30	1.95 (1.31)	67.17	2.60 (1.24)	47.69	2.91 (1.24)	42.6
Adhesive fiducials	3.12 (1.63)	52.24	3.24 (1.83)	56.48	3.65 (2.03)	55.61	3.83 (2.08)	54.30
Mask	3.20 (1.40)	43.75	3.19 (1.64)	51.41	2.16 (1.36)	62.9	2.41 (1.42)	58.67