Surface laser registration in ENT-surgery: accuracy in the paranasal sinuses--a cadaveric study.

Over the past decade, surgical navigation systems have found widespread use in ENT-surgery. Navigational accuracy highly depends on the registration process. The objective of this study was to assess the accuracy in the paranasal sinuses and lateral skull base after surface laser registration using the navigation system VectorVisionCompact (BrainLab, Heimstetten, Germany). Repeated measurements were performed on two cadaver heads. Sixteen titanium screw fiducials per head were placed in facial bones, the paranasal sinuses and the lateral skull base, thereby serving as exactly identifiable measurement points. The respective influence on measurement accuracy depending on the localization and conformation of the registration area was evaluated by performing symmetrically bilateral as well as strictly unilateral registrations. The resulting overall accuracy for a symmetrically bilateral surface laser registration was 1.13 +/- 0.53 mm, ranging from 0.77 (sinus frontalis) to 1.76 (petrous bone) mm, and thus proved to be clinically sufficient. Increasing distance between target point and registration area went along with a decline in accuracy. Navigational accuracy was significantly influenced by the choice of the registration area. Best accuracy was detected after symmetrically bilateral registration.