Abstract
The usefulness of CT in preoperative examinations for middle ear surgery was evaluated on the basis of whether or not it can provide a surgeon with useful information not available from the other preoperative examinations, such as microscopic examination, pure tone audiometry, impedance audiometry, equilibrium tests, conventional X-ray films, etc.
The findings of CT were compared with those obatained during operations and the following conclusions were reached:
CT is especially useful for the three purposes indicated below.
(1) to determine the patency of the attic air route to the mastoid antrum.
(2) to make differential diagnoses of middle ear diseases in the presence of obstructive pathology of the external auditory meatus.
(3) to make a rough estimate of the extent of cholesteatoma growth in the middle ear cleft, and to diagnose labyrinthine fistulae.
CT proved less effective or useless for the following three purposes.
(1) to secure detailed information on the status of the ossicular chain.
2) to determine the precise exetent of the growth of cholesteatoma.
3) to evaluate the postoperative status of the ear.
