[3D-navigation in nasal sinus surgery].
Mechanical, infra-red and electrofrequency 3D-navigation equipment enables the visualisation of a probe in a patient in the three dimensions ofa CT-scan. Such a system guarantees better orientation in difficult anatomical areas. 3D navigation is particularly suitable for nasal-sinus surgery as the bony structures are reproduced in precise detail on a CT-scan and bone parameters do not change during operation. These technical developments mean that not only the indications for operation but also the surgical approach have greatly altered. In functional nasal-sinus surgery the aim is to open up the sinus by removing all those structures which may hinder drainage. The mucous membrane with its mucociliary transport is spared and goes on to heal. - Prior to operation the patient's anatomical landmarks are tracked and spatially linked to the corresponding points on the CT-scan. The coordinates of these points are registered on a computer. A probe is moved around within the spaces, its coordinates are calculated and their position shown on a CT-scan. The patient's head is fixed in a frame that is able to move with the head. The advantage of the 3D-navigation system is its surgical and anatomical orientation. Disadvantages are its cost and, to a lesser extent, time requirements and the size of the equipment.