Two New Articles On Atraumatic CI Electrode Insertion And Residual Hearing Preservation

In a previous article we stated you want to assure your surgeon will be using residual hearing preservation techniques to get the best performance, even if there is no residual hearing remaining, in order to keep the electrode in the scala tympani (bottom of the three chambers) to get the best outcome, 1, 2 and to minimize the chance of triggering or exacerbating tinnitus. 4 Two new journal articles on residual hearing preservation have just been published; and anyone considering a CI should discuss these items with the surgeon.

A cochlea with a MED-EL electrode array partially inserted. Photo courtesy of Adrien Eshraghi MD, University of Miami Miller School of Medicine, Miami FL

A cochlea with a MED-EL electrode array partially inserted. Photo courtesy of Adrien Eshraghi MD, University of Miami Miller School of Medicine, Miami FL

In addition to the items in Selecting a Cochlear Implant Surgeon, you and the surgeon should review the Impact of Perioperative Oral Steroid Use on Low-frequency Hearing Preservation After Cochlear Implantation 3 by David Haynes MD & his crew at Vanderbilt; and Effects of CI Electrode Insertion on Tinnitus 4 by Thomas J Balkany MD in The Institute for Cochlear Implant Training blog. Although Balkany talks about how tinnitus can be generated when the basilar membrane is pierced, in fact “when CI electrodes ruptured intrascalar partitions and traversed between the scala, tinnitus had a 16% chance of being generated or becoming worse; while when electrodes did not traverse scala, tinnitus was not made worse.

Hybrid, or Electroacoustic Stimulation (EAS):

Back on May 28th 2015, Advanced Bionics received the CE marque by TÜV for their Naída CI Q90 EAS combination hearing aid/CI speech processor, joining their rivals at Med-El and Cochlear, which unlike the Austrian and Aussie systems uses a full length electrode insertion: We like this because if indeed residual hearing is lost, the full array is already in place and all 16 electrodes are enabled, and you have a conventional CI. With the shorter Med-El and Cochlear arrays, if you lose your residual hearing, you’re stuck with half a stim; and what’s more, due to fibrous tissue growth, the surgeon cannot place a full length electrode in. We pointed out this inconvenient fact almost two years ago in The Curious Hybrid (EAS) Cochlear Implant Recipient, where the surgeon implanted a then-14 year old girl who has a progressive hearing loss with a short array.

    References:
  1. Cochlear Implant Programming: A Global Survey on the State of the Art (31 authors). The Scientific World Journal Volume 2014 (2014), Article ID 501738, 12 pages
  2. Role of electrode placement as a contributor to variability in cochlear implant outcomes (Charles C. Finley and Margaret W. Skinner). Otol Neurotol. 2008 Oct; 29(7): 920–928.
  3. Impact of Perioperative Oral Steroid Use on Low-frequency Hearing Preservation After Cochlear Implantation. Sweeney, Alex D.; Carlson, Matthew L.; Zuniga, M. Geraldine; Bennett, Marc L.; Wanna, George B.; Haynes, David S.; Rivas, Alejandro. Otology & Neurotology: October 2015 – Volume 36 – Issue 9 – p 1480–1485
  4. Effects of CI Electrode Insertion on Tinnitus, by Thomas J Balkany MD. Institute for Cochlear Implant Training, October 1, 2015
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About the author

Dan Schwartz

Electrical Engineer, via Georgia Tech

2 Comments

  1. Leah OConnor
    April 6, 2016 at 3:28 pm

    My CI was implanted Dec 2915 in my right ear. If my tinnitus is due to the electrode placement, is there anything that can be done? But more importantly can incorrect placement lead to CI failure and/or imbalance? If so how would it fail? Due to changes in balance and hearing the doctors think I might have an acoustic neuroma in right ear. They found a growing AN in the left ear 6 months after CI and treated it with Gamma Knife, so it is also possible that the radiation damaged CI. Or maybe (hopefully) it is only the processor programming that is the problem. How do I get reliable information? I get the feeling that no one wants to give me information.


    • Dan Schwartz
      April 6, 2016 at 7:02 pm

      Leah, incorrect electrode placement will not cause an electrical failure; however I’m surprised they used a gamma knife with the implant sitting right there, as Yes, the internal circuit could easily be destroyed as it’s ionizing radiation — Sheesh!, this is semiconductor physics 101!

      I noticed you’re in Chicago: Which CI center did you use? Also, which implant did you receive?

      The Good News: If you need treatment again, there’s a proton accelerator for therapy in Naperville (next door to Phonak USA’s offices of all places). It’s on the south side of the Ronald Reagan Freeway just before the Winfield Road exit, in the same office park as the former Office Depot HQ (map). Since proton beam radiation is much more tightly focused, you may — and I underline may — be able to have it excised without damaging the implant. However, this would need to be coordinated with the engineers at your CI company.


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