I want you guys to know this: Due to privacy rights for patients, doctors do not really disclose the failures of any procedure. This is why we do not hear about it as often as they do actually happen.
I've heard failure rates for CI was in a high % neighborhood. I will not state what the % is primarily because first: I am not a doctor, second: I do not have a good source, third: I do not want to influence anyones decision.
I know of a model who got a paralysis of the face after having the operation.
I also know of a lady who was an interpreter getting a CI (I dont know why, she could have used HA's but..) because she loved her occupation. She said it was the worst thing she has ever done in her life. The sounds is not really what you hear as a hearing person.
Just saying that the doctors will glamorize the implantation (for obvious reasons) and not tell you the actual failure rates, just because the information is not handy.
When I had my daughter first tested for her hearing loss, I went to the Denver University medical center to have it done. Guess what was plastered all over the walls - CI posters. No hearing aids, no other means of accommodations, etc. Personally, being a Deaf individual, I found that audist.
That is all I have to say. Just wanted to have that small piece of input.