Comparison of 4 Registration Strategies for Computer-aided Maxillofacial Surgery

Purpose: Surgeons have recently started to use computer-aided surgery (CAS) to assist with maxillofacial reconstructive surgery. This study evaluates four different CAS registration strategies in the maxillofacial skeleton.

Materials And Methods: Fifteen fiducial markers were placed on each of four cadaveric heads. Four registration protocols were used: 1) group 1-invasive markers, 2) group 2-skin surface, 3) group 3-bony landmark, 4) group 4-intraoral splint. Two observers registered each head twice with each of the four protocols and measured the target registration error (TRE). The process was repeated on two different navigation systems for confirmation.

Results: The mean TRE values were: invasive, 1.13 +/- 0.05 mm (P < 0.05); skin, 2.03 +/- 0.07 mm (P < 0.05); bone, 3.17 +/- 0.10 mm (P < 0.05); and splint, 3.79 +/- 0.13 mm (P < 0.05). The TRE values were consistent across CAS systems.

Conclusion: Of the techniques tested for CAS registration, invasive fiducial markers are the most accurate. Skin surface landmarks, bony landmarks, and an intraoral splint are incrementally less accurate.