No abstract

In the first protocol, PA did not improve after the registration of the landmarks, and PA of the target was evaluated as 4.9+/-0.64 mm. In the second protocol, PA was reduced after screw registration for all landmarks with a mean PA ranging from 0 to 2.3 mm.

In the first group, the PA was 7.08 ± 0.59 mm and 0.77 ± 0.17 mm (mean ± SEM, p < 0.0001) before and after screw registration, respectively. In the second group, the PA was considered as accurate by the surgeon in all cases and no drift of the system was observed. Computer-assisted surgery was never abandoned due to increased stability of the bone-anchored emitter.