In virtually all cases of AM, the inner ear, hearing nerve and balance system are present. Malformations of the middle ear bones, the ear canal and facial nerve system occur and can be evaluated with a CT Scan which allows us to see into and evaluate the deeper structures of the ear.
Based on the relationship of these structures and how close to normal they are, experienced surgeons can predict the chance of success for different treatment strategies such as creation of an ear canal or implantable device, etc. For those patients with hearing nerve abnormalities, malformations of the inner ear are visible on CT scans. CT scans are read and graded using a 10-point scale that assigns points to several different anatomic structures as follows:
By examining CT scans, which most simple terms are many sections of x-rays stacked on top of one another like slices in a loaf of bread, surgeons are able to visually reconstruct anatomic structures when considering how to provide hearing to a working inner ear. A CT scan showing a normal side canal (air is black, bone is white and tissue or fluid is grey) and atresia in the other ear would look like this:
Using advanced software techniques, reconstruction of important structures can be performed. Dr. Roberson always uses the original scan to grade CTs, utilizing the 10-point J-scale. This allows for the gathering of maximum information and evaluation in our advanced software platforms. For information as to how CT scores predict our chance of surgical success see Outcomes and Complications. Some examples are as follows: