Of the three hearing bones, the one most likely to become “stuck” or “non-mobile” is the third one, the stapes bone. All three hearing bones oscillate in response to incoming sound. The stapes bone transmits that sound vibration to inner ear fluids where the vibrations stimulate inner ear sensory hair cells. On a fairly rare basis in some children, the third hearing bone, the stapes bone, is non-mobile from birth as a result of a genetic defect or developmental error sometime, probably, in the 2nd trimesterof gestation in the womb. Also fairly rare is that some older children and teens suffer from a disease called otosclerosis. In otosclerosis, the stapes bone becomes stuck, non-mobile, first starting as a minimal problem, and then getting progressively worse. The pattern of hearing loss is quite similar in both groups.
On CAT scan imaging, the birth defect problem may have minor abnormalities of the inner ear and somewhat misshapen first (malleus) and second (incus) hearing bones. Some CAT scans looking at the birth defect problem find no abnormalities. The otosclerosis problem is almost always visible on the CAT scan, differentiating from the congenital problem. This article set out to compare how these two groups of children and teens improved with surgery on the stapes bone.
The measurements were hearing tests and chart reviews to see what complications might have occurred. Forty-four pediatric ears were studied, 27 with a congenital stapes problem and 17 with otosclerosis. Those with the congenital defect came to surgery at an earlier age, as expected, than did the otosclerosis group. Thirty seven percent of the congenital group had minor other hearing bone malformations whereas none of the otosclerosis ears had hearing bone problems other than the non-mobile stapes. Those who had otosclerosis generally gained a little more hearing from surgery than did the congenital ears, probably because some of the congenital ears had more wrong than just the non-mobile stapes bone but both groups uniformly gained hearing in a “statistically significant” manner following surgery. There were no cases of deaf ear and inner ear function remained stable in all but one ear which was a bit worse. There were no cases of serious complications, in either group. Compared to other published medical literature, this article had quite similar outcomes. Another disease entity which can cause a non-mobile stapes is called “tympanosclerosis.” Published literature reviewing stapes surgery in ears with tympanosclerosis found hearing gains from surgery to be less than with the congenital problem and the otosclerosis reviewed in this article.
The authors’ conclusion: When performed by an experienced surgeon, stapes surgery is safe and effecive in children who have either problem, although hearing results are generally better with otosclerosis than with the congenital problem.