[Navigation-aided surgery for congenital cholesteatoma at the petrous apex]

Computer-aided navigation in otolaryngology has been used mainly for nasal operation and rarely for ear surgery. The reason for its limited use in ear surgery appears to be that microscopic observation may be sufficient in most cases of ear surgery. We report a case of congenital cholesteatoma at the petrous apex operated on using navigation. A 65-year-old man with facial palsy, deafness, and canal paresis in caloric test on the left ear was found in preoperative computed tomograph (CT) showed a large mass at the apex with an expansively eroded skull base and inner ear. Navigation used for the operation was magnetic (Insta Trak). A probe 3.2 mm in diameter was moved in the operative field and 3 axial CTs were simultaneously monitored on a workstation to show the tip location. With this image-guided system, cholesteatoma was thoroughly and safely removed. We concluded that navigation should be used for safe surgery, especially in ear surgery at the petrous apex, because anatomical identification is very easy and damage to vital areas around the inner ear, nerve, brain, and internal carotid artery could be avoided.