In both of these situations, it is possible to improve hearing by removing the stapes bone and replacing it with a micro prosthesis - a stapedectomy, or creating a small hole in the fixed stapes footplate and inserting a tiny, piston-like prosthesis - a stapedotomy. The results of this surgery are generally most reliable in patients whose stapes has lost mobility because of otosclerosis. Nine out of ten patients who undergo the procedure will come out with significantly improved hearing while less than 1% will experience worsened hearing acuity or deafness. Successful surgery usually provides an increase in hearing acuity of about 20 dB. That is as much difference as having your hands over both ears, or not. However, most of the published results of success fall within the speech frequency of 500 Hz, 1000 Hz and 2000 Hz; poorer results are typically obtained in the high frequencies, but these are normally less hampered by otosclerosis in the first place.