gms | German Medical Science

Introduction: The reliability of image-guided surgery is determined by the localization accuracy of the navigation system. Navigational accuracy highly depends on the registration method. We assessed the accuracy after surface laser registration using the navigation system VectorVisionCompact (Brainlab, Heimstetten).

Materials and Methods: Measurements were performed on cadaver heads. Fiducials were placed in the paranasal sinuses and the lateral skull base fixed by titanium screws, thereby serving as measurement points more reliable than methods applied in previous studies [Ref. 1], [Ref. 2]. This procedure proved particularly advantageous as it allowed us to obtain exact accuracy values directly in areas of ENT-surgery. Furthermore, the respective influence on measurement accuracy depending on the choice of the registration area was evaluated.

Results: The accuracy of the navigation system after surface laser registration was acceptable: The resulting overall accuracy for a symmetrically bilateral surface registration was 1.13 ± 0.53 mm. Increasing distance between target point and registration area went along with a decline in accuracy. Measurement accuracy was significantly influenced by the choice of the registration area. Best accuracy was detected after symmetrically bilateral registration.

Conclusion: When choosing the registration area, care should be taken to use points for scanning that are symmetrically distributed and cover as much of the patient’s face as possible. It is decisive to consider the registration points when preparing the operation side. To gain the best results it may often be necessary to do the scanning before patient’s positioning and sterile covering.