[Modified procedure for patient registration for navigation control instruments in ENT surgery].

PROBLEM: Surgical navigation and navigation-controlled instruments demand a robust and precise patient registration process. For navigation in the skull, a bite-splint-based registration method has been widely applied, which had to be manufactured by dental technicians. The additional cost and time could be avoided by directly using the manufactured imprint, which is prepared by the ENT surgeon in one step.
MATERIAL AND METHODS: This study examined the re-positioning accuracy for three silicon materials in a laboratory study with a 3D measuring device (Faro-arm) after several re-positioning cycles (simulating erosion) in comparison to the gold standard.
RESULTS: The mean deviation after two cycles was lower for all three materials compared to the gold standard. Only C-Silikon Optosil was better then the gold standard after all cycles and with a deviation of 0.17 mm it well below that of the conventional bite-splint (0.28 mm). The additional cost benefits of 10 euro per imprint compared to the bite-splint with >100 euro favor this material for clinical application.
CONCLUSIONS: As a consequence of this investigation Optosil was successfully used in 6 patients during the period from 01.09.2007 to 30.11.2007. The bite-splint was manufactured completely in the ENT department and could be used during the planning CT and surgery. The resulting accuracy corresponded to the experiences gained in previous surgery with a maximum deviation of 0.87 mm. The favorable ergonomic characteristics for patient and surgeon could be confirmed. As a result of this study this clinic now exclusively uses the procedure described in this article for bite-splint-based registration.