Sunday, 21 May 2006 - 1:06 PM

Thank you so much for your information on cochlear implant. When we consider MAHITHA's case, we know that she is unable to catch the sounds inroder to respond. But we does not know exactly what happens inside. Because of your disussion, we could exactly know the mechanism of the hearing system.

I want to know the causes that lead to deafness in MAHITHA's case? I heard its hereditory. Is that true?

Monday, 22 May 2006 - 8:04 AM

Alright, I like how you divided the parts of the hearing system, it makes things easier to understand.

Well, I found most of the things to be pretty clear but I was wondering what kind of mistakes or errors can/do surgeons create during these implants? Can something seriously go wrong? Are there any side-effects?

I also know that the patients should check with many specialists before getting the implant done, so what is it that the specialists look for, in the patient? What is the criteria?

And finally, does this treatment work for the lifetime?

Alright, thanks in advance, will wait for your reply.

Monday, 22 May 2006 - 5:05 PM

Its interesting that u raised the issue of errors/mistakes during the implantation procedure (I presume that is what you mean).
I have seen the video of one procedure, and I have spoken to several surgeons who regularly perform the procedures. In order to give a scientific answer to your question, I did a medline search. The following is an extract from an article in an Italian medical journal, I will try to explain the jargon:
"In cochlear implant surgery, major complications, requiring revision procedures, do not exceed 5% of cases reported. Less frequent are problems that call for specific technical solutions. In 44 multichannel implantations (out of 54 cases) adverse conditions occurred and were successfully resolved in 6 patients: 1) delayed wound breakdown (one case); 2) chronic otitis media (three cases); 3) cochlear obliteration (two cases). Problem 1 was managed with the excision of an ellipse of skin including the devitalized areas under local anesthesia. The electronic package was left untouched, and the freshly cutaneous edges were mobilized and layer-sutured. Problem 2 was solved through a two-stage procedure. The chronic ear was dealt with as usual (myringoplasty, tympanoplasty, revision of a radical mastoidectomy). In the second stage the cochleotomy and device implantation were carried out. Problem 3 is a major issue for the surgeon. Following the Lehnhardt technique we drilled along the basal cochlear turn using the sharp line between the yellowish otic bone and the white newly formed bone as a landmark, until a patent s.tympani was found at the ascending part of the 1st or at the beginning of the 2nd turn".
Let me explain that every surgical procedure has a complication rate, and 5% is universally considered as a very good rate.In this paper the authors mention 6 problems in 44 patients which is more than 12% but they have included minor complications also. The first 4 were actually infections, so they may not be related to the competence of the surgeon, rather they may indicate inadequate preparation of the patient, or inadequate precaution during the procedure (which should definitely not happen!)The last 2, called "cochlear obliteration" is a major problem (from the authors' account). They did some procedure which to me sounds like a tunneling procedure to get the patent portion of the cochlea, and managed to solve the problem. Now what we need to do is try and learn a bit more about this problem. As far as Mahita is concerned she is beyond the stage of the first two complications (she can still develop CSOM, I guess).
As for your second question, I think just going to a lot of specialists does not help, one should try and learn as much as possible so that one can, even as a layman, take an informed decision. As for criteria, the only criterion is a child with cochlear deafness, an intact cochlear nerve, and scope for language development (i.e., age below about 5 years). Done beyond this age, language development is not adequate and the procedure may be wasted.
As far as duration of the treatment, the device is a permanent one, and apart from replacement of batteries, no revisioning is usually required, unless the device gets displaced or there is a local infection requiring intervention.

Monday, 22 May 2006 - 5:08 PM

Cochlear deafness is a congenital for of deafness, which actually means that it is present from the time of birth. Usually, it is a genetic form of deafness, but what actually happens, what gene is responsible, what is the mechanism of the deafness, I still don't know, but I can try to find out from internet resources.In Mahitha's case, we know that it is an inherited form.

Tuesday, 23 May 2006 - 4:20 AM

Wow, that was a lot of information and thank you for taking your time and answering the question. Yes, I was referring to the errors during the implantation procedure.

Ok, coming to your answer, I figured out the COM part of the complication, but what is the "inadequate preparation" you mentioned? Can you explain that a little more?
I think I sort of understood the rest of the things concerning the complications, maybe it'll be more clear when we continue further.
I would definitely like to hear more about cochlear obliteration...I'm not too sure how it actually occurs. And in the case mentioned in the article, I couldn't figure out if it was the problem or the solution. (i'm sorry if that sounds silly)
And coming to Mahitha's case, do you think that her fever after the surgery has anything to do with COM? (Although it hasn't exactly been chronic).

Alright, I will wait for your reply, thanks!

Tuesday, 23 May 2006 - 2:32 PM

"Inadequate preparation" refers to pre-operative preparation; every surgical procdure requires that the patient be adequately prepared for it, be it physically, mentally, or psychologically. Surgical procedures performed in an infected areas are highly risky and suscetible to worsening of infection and failure of the procedure. So if there is a pre-existing infection, the procedure should be deferred till the infection is brought under control; this also is part of preparation, and in my reply, I meant indadequate infection control prior to procedure.
As far as cochlear obliteration is concerned, it seems to be a fibrotic process, and some diseases cause cochlear obliteration, and this may be an indication for cochlear implantation. It apparently can be a complication of the procedure, and is fairly serious, because the device may become non-functioning. It can lead to explantation of the device also.
i have another interesting thing for you, if you copy and paste the following URL in the address bar u will get the abstract of a recent paper, which will give u an idea of what sometimes happens when COM develops in an implanted patient.


[http://www.otology-neurotology.com/pt/re/otoneuroto/abstract.00129492-200604000-00007.htm;jsessionid=GyDJnVTf2vBW7CLmVgQXvKYJBwlpGGQnSm89sP85VhnbrL432vvJ!-1542589964!-949856144!8091!-1 ]

In my next post I will try to provide some more research information on which cochlear implant patients are at risk for COM.

Wednesday, 24 May 2006 - 9:37 AM

Alright, thanks again for answering my questions. Yeah now I seem to understand cochlear obliteration after the way you described it in your last post. Also, the link you attached was pretty interesting and boy, the patient had to go through ear obliteration...that sounds really serious!!
I forgot to ask in the previous post, I went through some pictures of people who underwent the implantation and the device is actually outside in the open. So i was wondering if the patients need to take extra care to protect it. I mean when they wash their hair and do different things near that area.

Well, I will wait for you next post and see whatelse I can learn, thanks.

Friday, 26 May 2006 - 10:40 AM

CIs actually have two components, the actual implant which is inside and for which surgery is required and which requires drilling of the bone; the other part is the processor and a coupler. The processor is just under the skin and is not really visible. In some countries like UK they have models in which a plug is attached from the outside and which can be replaced, when desired, with a superior model which has arrived in the market as a result of devleopment. In the usual implant, there is an element which can be removed at bed time and during bathing or when going swimming just like in the hearing aid; it is not recommended to wear it while swimming because of possible damage to the electronic components. Upon removal of this component the patient experiences absolute silence. There is a battery in the processor which can be recharged and changed quite easeily. The electrode array inside can neither be seen nor removed easily; if the patient wants to reverse the procedure due to lack of benefit, then removing the electrode part will require a surgery. The electrode array inside does not have any battery, and does not have any electrically charged component i.e. it is inert. On the other hand, the transmitter in the processor is charged and the electrical charge that travels down the electrode array is derived from the transmitter.