[Registration strategies for the application of the navigation system Fiagon at the lateral scull base]

Abstract

Objective: The aim of this study was to evaluate a new navigation system (Fiagon GmbH) at the lateral skull base.

Material and methods: We performed repeated measurements and registrations on titanium screws, which were attached to specific anatomical locations on 5 temporal bone specimens. The focus of the investigation is to determinate the Target Registration Error and a comparison of different registration methods.

Results: Use of the navigation system seems to be practicable at the lateral scull base. For a registration strategy with 3 onesided attached Fiducials the Target Registration Error is 0.8 mm on the surface of the mastoid and in the mastoid cavity. The measurements at the inner ear canal showed a mean deviation of greater than 1.6 mm. In the comparison of different registration methods the best results were found for registration on titanium screws attached on both sides of the head, followed by surface registration at the face including laterobasis followed by registration in the mastoid cavity only.

Conclusion: The measured values correspond to our clinical expectations and can be used if the existing Target Registration Error is known and respected. An intra-operative imaging may allow the application of titanium screws for navigation (gold standard) within the same general anesthesia during surgery.