CT evaluation of congenital aural atresia: what the radiologist and surgeon need to know.

Abstract

The preoperative evaluation of aural atresia and stenosis is strongly dependent upon high resolution CT. We have devised a 10 point surgical rating scale based on high resolution CT of the temporal bone that will provide radiologists with a stepwise method of evaluating these scans and will allow them to communicate these findings to otologic surgeons in a consistent fashion. We prospectively evaluated 1,500 patients with aural atresia or stenosis for eight critical areas of temporal bone anatomy, each area receiving 1 rating scale point, with the exception of the presence of a stapes, which received 2 points. The appearance of the external ear received the final point on the rating scale since the external ear is formed earlier than the middle ear and helps to predict its deformities. The presurgical score was utilized in selecting surgical candidates and was correlated with the intraoperative findings as well as the postsurgical results by comparing pre- and postoperative speech reception threshold. Patients with a presurgical rating of < or = 5 were not considered surgical candidates. Otherwise, the percentage of successful surgeries corresponded roughly to the rating scale. Thus, a presurgical rating of 8 points translates into an 80% chance of restoring hearing to normal or near-normal levels.