A New Armless, Computerized Guidance System for Functional Endoscopic Sinus Surgery

A new device, InstaTrack, provides rapid, accurate intraoperative anatomic localization during functional endoscopic sinus surgery (FESS). It is an intraoperative guidance system that uses an armless and frameless electromagnetic position-sensing probe to correlate intranasal or sinus anatomy with the patient's computer-loaded preoperative computed tomography (CT) images. This system has significant advantages over other methods (articulated arm and optical system) currently being developed. Initially the patients are correlated with their CT images with an automated technique that compensates for head movement. Subsequently the tip of the position-sensing probe is placed on an intranasal or sinus anatomic site, and its corresponding location immediately appears on each of three orthogonal CT images displayed on a monitor. This unique system conveniently allows the surgeon to perform intraoperative anatomic localization using a standard surgical instrument. Using both fresh cadaver heads and patients, the InstaTrack has been tested and proved capable of localizing structures in surgically critical sites and simultaneously displaying the probe position in the coronal, sagittal, and axial planes. Reproducible accuracy has been readily achieved in these trials. Not only will rapid, accurate localization aid the surgeon in avoiding well-documented major complications of FESS but it will extend the usefulness of FESS and increase the surgeon's confidence when there is profound mucosal disease, neoplasia, or dangerously positioned pathology.