Workspace definition for Navigated Control Functional Endoscopic Sinus Surgery

ABSTRACT For the pre-operative de“nition of a surgical workspace for Navigated Control R Functional Endoscopic SinusSurgery (FESS), we developed a semi-automatic image processing system. Based on observations of surgeonsusing a manual system, we implemented a work”ow-based engineering process that led us to the development ofa system reducing time and workload spent during the workspace de“nition. The system uses a feature based onlocal curvature to align vertices of a polygonal outline along the bone structures de“ning the cavities of the innernose. An anisotropic morphologic operator was developed solve problems arising from artifacts from noise andpartial volume eects. We used time measurements and NASAs TLX questionnaire to evaluate our system. 1. INTRODUCTIONFunctional Endoscopic Sinus Surgery Functional Endoscopic Sinus Surgery (FESS) is a minimally invasive surgical technique removing in”amed tissuefrom the nasal cavity and paranasal sinuses. It improves the air ”ow and leads to a regular drainage of thesinuses. In FESS, surgeons use conventional and power instruments, usually a shaver, for manual preparation.Orientation in sinus surgery is very dicult for a surgeon and the intervention site is usually observed with anendoscope. Atypical anatomy (low scull base, former operation, missing bone tissue) increases the complexityand elevates the risk of an iatrogenic injury.