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BackTable / ENT / Podcast / Transcript #15
Podcast Transcript: Adult Cochlear Implantation
with Dr. Jacob Hunter
We speak with Dr. Jacob Hunter about Adult Cochlear Implantation, including patient workup and counseling, surgical tips and tricks, and post procedure followup. You can read the full transcript below and listen to this episode here on BackTable.com.
Table of Contents
(1) Cochlear Implant vs. Hearing Aid
(2) Indications for Cochlear Implantation
(3) Referral Pathways for Cochlear Implantation
(4) Patient Screening & Evaluation for Cochlear Implantation
(5) Counseling Patients About Cochlear Implants and Hearing Aids
(6) Imaging for Cochlear Implantation and Contraindications
(7) Comparison of Cochlear Implant Devices
(8) Surgical Technique for Cochlear Implantation
(9) Potential Complications of Cochlear Implantation
(10) Perioperative Management of Cochlear Implant Patients
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[Ashley Agan MD]
Well, we do have a treat for our listeners today. For those of you who are new to the show, welcome, and for those returning, we thank you for stopping by again, and we hope that you'll subscribe, rate, and share. Today, we have Dr. Jacob Hunter. He's an assistant professor and a Dedman Family Scholar in Clinical Care in the Department of Otolaryngology, Head and Neck Surgery at UT Southwestern Medical Center in Dallas, Texas. He obtained his medical degree from Albert Einstein College of Medicine in the Bronx, New York, and also completed his residency in otolaryngology there. He then completed his fellowship training in neurotology at Vanderbilt University Medical Center in Nashville, Tennessee. He's a member of the North American Skull Base Society, the American Neurotology Society, and the American Cochlear Implant Alliance. He's here today to talk to us about adult cochlear implantation. Hey, Jake. Welcome to the show.
[Jacob Hunter MD]
Morning.
[Gopi Shah MD]
Welcome.
[Jacob Hunter MD]
Thank you, guys. This is awesome. Thank you for the invitation.
[Ashley Agan MD]
So I know that we kind of did the formal intro there, but before we get started, tell our listeners a little bit just about who you are and about your practice.
[Jacob Hunter MD]
So, as you mentioned, I'm, I guess, a neurotologist at the university. I also cover the city and county hospital and get down to the VA about once a month. While we are talking about adult cochlear implantation today, about 20% of the practice is pediatric, so I do implant kids and do meet a lot of kids with hearing loss. Some of the practice is skull-based, but, as it turns out, a lot of patients are coming to me for hearing loss and talking about their hearing aids and talking about what might a cochlear implant help them or what's another option outside of a hearing aid.
(1) Cochlear Implant vs. Hearing Aid
[Gopi Shah MD]
So for the listeners who may not know, can you just go over maybe the basics of what is a cochlear implant, who's it for, how it works.
[Jacob Hunter MD]
A cochlear implant is essentially ... I think the most basic way of putting it is it's a little wire that we place in the cochlea that fires directly essentially on hearing nerve, and so the idea is that when patients can no longer receive any benefit from a hearing aid, and a hearing aid, again, is basically just a microphone that's boosting the sound into the ear, then we start talking about a cochlear implant. At least the way I felt I was trained was that maybe when people are struggling with their hearing aids, they might be a cochlear implant candidate, and that can be the case, but many times hearing aids aren't fitted appropriately, and who's to say where they ... I know the idea is trying to get a hearing aid off the store shelf, and there's some benefit to that but also some complications. But many people struggle with their hearing aids, so that's not the easiest rule of thumb. Generally, when they're at the limits, then they're a candidate for this surgical procedure to place the wire in the cochlea, so to speak.
[Ashley Agan MD]
I think, for some people, when they think cochlear implant, they think it's going to be something that's just completely implanted and that you don't really see it all. So can you talk about the components, or when we see these patients who have the external process, what all is going on underneath that?
[Jacob Hunter MD]
No, and that is a good point. I actually do have a conversation probably once a week to delineate that key feature. While the wire is in the cochlea and you have essentially a computer under the skin, you're also wearing an external device that allows people to still hear or allows that patient to hear, transmitting the information through the skin into the computer underneath, so you have that external device. Generally, I joke with patients that they can take it off and they won't be able to hear their spouse if they so choose, but their spouse will clearly know that they're not listening to them.
(2) Indications for Cochlear Implantation
[Gopi Shah MD]
So just to rewind for ... You said when patients get to the max of their hearing aids. Is that for both ears, one ear?
[Jacob Hunter MD]
Traditionally, it was both ears. Back in 2019, the FDA did approve cochlear implantation in single-sided deaf patients, and so what that means is essentially you have normal hearing in one ear and then no hearing in the other. That doesn't necessarily mean insurance would cover it, but we're definitely implanting more people today with single-sided deafness than we were 10 years ago, so to speak. While I go back to what were the indications when people were at the limit of the hearing aids, the criteria are expanding. I know we're not talking about pediatrics, but the pediatric criteria just recently expanded, and we're kind of reaching out more and more, finding more and more people can benefit from them.
[Ashley Agan MD]
And for your single-sided deafness patients, are most of those patients who have had a sudden sensorineural hearing loss or have had surgery or trauma? Is it just kind of a mixed bag?
[Jacob Hunter MD]
It's kind of a mixed bag. I mean, I can think of a patient yesterday who we don't really know the cause. She recalls, I believe, a sudden loss. The data that was approved by the FDA only included people that had to have had their hearing loss within the past 10 years. That's not a hard and fast rule. There's definitely people that succeed and do well with an implant that have been deaf longer, and so, obviously, the longer the patient goes, you're going to maybe not recall what exactly happened. But it is a mixed bag, some trauma or surgical related, some sudden hearing loss, some Ménière's, so Ménière's disease, meaning it's a slow degradation of their hearing loss over time.
[Gopi Shah MD]
So in terms of your patients, could you tell us a little bit? You have your maybe sudden sensorineural or maybe somebody in the last 10 years that slowly has lost. Then I kind of think of maybe the older ... I think of older, 80-year-old patients, like a older age, I feel like, we're starting to implant. Can you just characterize the buckets ... Is it after a history of meningitis? What kind of history do they usually have?
[Jacob Hunter MD]
I think that's an important distinction. A single-sided deafness is a small, small, small, small, small fraction of the actual cochlear implant practice that we have. I'm actually one of three adult cochlear implant plantation surgeons at UT Southwestern with Walt Kutz and Brandon Isaacson, and so I would venture to guess that it's somewhere between maybe 5%, maybe 10% are the single-sided deafness patients. But, traditionally, in the big portion and the percentage of these patients are older patients that just have what we call presbycusis, that it's just a natural hearing loss as we get older and that they start getting fitted with hearing aids.
[Jacob Hunter MD]
Sometimes, I think we all know friends and colleagues that are in their 20s, 30s, and 40s that wear hearing aids, but these patients wear hearing aids for many years. Generally, these patients are talking 10, 20, even 30 years, and so then they're at the point where you've turned the hearing up as loud as possible and now we're talking about a cochlear implant, and that is the predominant number. Meningitis in an older adult or any adult is a very rare occurrence, unlike what you might see in the pediatric population. But the biggest, biggest thing is just a natural loss of hearing.
(3) Referral Pathways for Cochlear Implantation
[Ashley Agan MD]
And do you find that most of your referrals for cochlear implants are coming from audiologists who feel like they're throwing their hands up, like they've optimized the hearing aids as much as possible and now the patient may need to be evaluated for something else?
[Jacob Hunter MD]
Definitely. A very large portion are coming from audiologists for the reasons you point out. A large portion is also coming from otolaryngologists. I mean, you might be splitting hairs here because they might be in their audiology practice that are at their wit's end about what they can do to help the patient, and so then the otolaryngologist might then refer to them to us to evaluate. But, definitely, there's a large audiology referral base because they're the ones dealing with this and the frustrations of the patients on a daily basis.
[Ashley Agan MD]
Yeah. I think as a general otolaryngologist, I was looking forward to talking to you about this today because I want to make sure that I am on the lookout for these patients. I know I read that we under-implant adults who would be candidates, right? So just for those general ENTs out there, what are some good questions, screening questions, where we could kind of be on the lookout for patients that might benefit from at least an evaluation?
[Jacob Hunter MD]
Well, I want to, I guess, take it a step back. It is estimated that only roughly about five to seven percent of patients who could benefit from a cochlear implant actually get a cochlear implant in the States, and that's mind-boggling. You can actually take it even a step further back. It's like only a quarter of patients that could benefit from a hearing aid actually get a hearing aid. We can go on and on and talk about the reasons why that is the case. I think you talk about one, understanding that maybe not only general otolaryngologists but audiologists might not understand when a cochlear implant patient might be a candidate, and that's a little difficult.
[Jacob Hunter MD]
I know some of the research that we've published, and it's recently come out at a couple other centers, about trying to help the audiologist or the general otolaryngologist look at maybe an audiogram to parse things out. But maybe back in the napkin, back in the envelope, just gestalt, it's those patients that are with well-fit hearing aids, they're kind of gone through a number of hearing aids that are still struggling. I wouldn't want to characterize a specific environment or a specific situation where they're saying, "Oh, now I struggle in a restaurant." Many patients struggle in restaurants. So I don't want to say that there's certain lifestyle issues that might mean you get an implant. I think a good rule of thumb is that they're at the limits of their hearing aid.
(4) Patient Screening & Evaluation for Cochlear Implantation
[Jacob Hunter MD]
Now, you can dive deeper into the audiogram, and so the audiogram consists of what, I think, at least the three of us are aware of. It's about those tones, so we have that pure tone audiogram, but a big component also is that word recognition score, and so if they do poor, significantly poor on that, so we're talking ... Technically, our data demonstrated under 60% word rec in the better hearing ear, and that has been reinforced by a couple other studies, that it's reasonable to talk to the patient about a cochlear implant. That's not a hard and fast rule. The audiogram is not what determines who or who does not qualify for an implant, but I do think it gives the general otolaryngologist, the audiologist, someone who has these audios in their office a good idea of maybe when should I talk to them about an implant, when should maybe I send them to get further testing. There's obviously people that qualify that have better word recs. There's obviously people that have terrible word recs that don't qualify. But 60 in the better ear is generally a good rule of thumb. I don't know if that answered your question.
[Gopi Shah MD]
Yeah, no, it's helpful. For word recognition, is that the same thing as speech discrimination, or is it more SRT-
[Jacob Hunter MD]
Yeah, there-
[Gopi Shah MD]
... or is there a special test, like the word and sentence? Can you kind of go over-
[Jacob Hunter MD]
Yeah, it's speech discrimination, word discrimination. These are words that are presented to the patient in a soundproof room without their hearing aids. So it doesn't mean they'll understand maybe the context of the sentence. It's just single words that sometimes ... There are 25-word lists, 50-word lists. I think most of the time most practices are administering 25-word lists. There's data to suggest that you could administer 10 and then depending on how they do the 10, then maybe you should expand to 25. But I think, at least, our audiologists predominantly do 25. I mean, it's per se correct, how many they get correct that were asked. That's not on all audiograms, but every audiogram that we see, at least that we conducted at our centers, that is tested.
[Ashley Agan MD]
And you said that's without the hearing aid?
[Jacob Hunter MD]
Without the hearing aid, yeah.
[Ashley Agan MD]
Without. And that's just a word, right? There's no context, there's no sentence.
[Jacob Hunter MD]
Correct.
[Ashley Agan MD]
It's just a word.
[Jacob Hunter MD]
Correct.
[Ashley Agan MD]
Repeat this word.
[Jacob Hunter MD]
I'm maybe jumping the gun here, but which is different than when we determine who's a cochlear implant candidate because when an adult goes for a cochlear implant evaluation, one of the tests that can be administered are actually sentences with their hearing aids. So they're tested in their hearing aids. Another test is actually giving them words with their hearing aids, and there's pros and cons to doing that versus sentences. But many times and most of the time, at least at our centers, we're administering sentences.
[Gopi Shah MD]
Yeah. So let's go into ... So you have a referral for a possible hearing aid, excuse me, for a cochlear implantation. What's your clinic visit like? Let's go into that a little bit. What are some key things that you ask for in your history? What do you look for?
[Jacob Hunter MD]
So I always ask, "We're here to talk about your hearing loss. Tell me about your hearing loss." I like asking how long they've had hearing loss, how long have they worn their hearing aids, how old are their current set. Sometimes, patients come in and they haven't worn hearing aids, and that's not to say that they can't still benefit from a cochlear implant, but we'd probably just fit them with properly fitted hearing aids and have them test them out before actually taking them to the next step on an implant. But I ask about-
[Ashley Agan MD]
How do you-
[Jacob Hunter MD]
Go ahead.
(5) Counseling Patients About Cochlear Implants and Hearing Aids
[Ashley Agan MD]
Sorry to interrupt you, but as you're talking, I'm thinking about so many patients who come in and have hearing loss, you talk about that, and they're like, "I tried hearing aids and they didn't work." Do you have any pearls on how to talk to patients about how that's just about giving hearing aids a good shot and when you know that they've truly given them a good shot?
[Gopi Shah MD]
Is this kind of like the sinus rinse question? Have you done the rinse? Have you done saline rinses, and it just doesn't-
[Ashley Agan MD]
Every day.
[Gopi Shah MD]
Sorry, joke. Anyways.
[Jacob Hunter MD]
That's a very good question. I personally don't have any pearls. It's amazing. I'm jumping ahead a little here, but when we do that cochlear implant evaluation, the audiologists do test the fit of their hearing aids. They see if they're fit appropriately to the hearing profile of the patient. I'm unaware of data, but I personally was surprised to see how often those hearing aids are not fitted appropriately for the patient. There can be many reasons for that. Maybe they hadn't seen an audiologist for a while. Maybe they just weren't fit appropriately. So we fine tune the hearing aids so that they are at the maximum benefit to the patient, and sometimes we don't even like them. We'll have the patient borrow our own hearing aids to really, really make sure we're testing. The key here is testing in the best aided condition.
[Jacob Hunter MD]
But I don't. I like to, I don't know how to put this, maybe share the experience with the patient to understand. I'm sure they're frustrated. That's why they're here talking with me. I validate their frustration and tell them that, obviously, there's many different types of hearing aids and perhaps there might be a better hearing aid that might work better for them. At the other end of the spectrum, it's also like, well, maybe a cochlear implant is right. It's an interesting question to ask. Many times, these patients are coming to me, and they're like, "I need a cochlear implant. Just put it in." It's like, "Whoa, whoa, whoa, whoa, we need to appropriately counsel, make sure that this is actually going to help your hearing."
[Jacob Hunter MD]
I feel I'm talking people back a little more than saying, "A cochlear implant's going to help you," which I do think speaks to the fact that these patients are coming in late. They're not coming in early, so to speak. Maybe they were fitted appropriately. I don't really know. Maybe they weren't. So, again, trying, I guess, just validating the patient's frustrations and taking it one step at a time. Let's get the hearing test. If they're here for an evaluation, let's see what your evaluation shows, and let's talk some more.
[Ashley Agan MD]
Yeah, I think that's helpful. I think that's great advice. Back to walking through the visit with you and what to expect.
[Jacob Hunter MD]
I ask their ear history. I ask about whether they've had any infections or any drainage, any pain. Have they ever had any ear surgery? I ask about, I think I mentioned, their hearing aid experience. I ask about a family history. I ask if they've ever had any head or neck imaging that would include the ears. I also, not always, but I also ask do they ever know anybody with a cochlear implant. Some of our research suggests that people who do know people with a cochlear implant generally do proceed with surgery. Not everybody who qualifies for an implant elects to proceed with surgery, but the people who generally know somebody do, which kind of makes sense. They know somebody that's been down that path, so to speak. That's generally the big picture of what I'm asking.
[Jacob Hunter MD]
Then it depends. So we generally always get an audio. If they're coming from within a practice, say, Ashley, you're sending somebody, they've already had that audio, so then they'll actually get their cochlear implant evaluation before they see me, whereas if it's coming from the community, most from the community, we're getting the audio. They see me then getting an audio then getting a cochlear implant evaluation, and then I generally talk with them more after that evaluation, but if a patient's poorly fitted or if we feel hearing aids are best for the patient, they might not be back in my office. The audiologist might send them out. I always am aware of that. I'm always more than happy to talk to a patient, but sometimes they're like, "Listen, if we're not talking about the surgery anymore, I don't need to talk with Dr. Hunter anymore."
[Gopi Shah MD]
So just in terms of ... Because I'm at Children's, I understand that for pediatric cochlear implantation it's a multidisciplinary team visit. We have social work, the implant surgeon. They have seen our family-focused hard of hearing, Dr. Rachel St. John. There's audiology involved. In an adult cochlear implant candidate, is there a need or is there a role for multidisciplinary team?
[Jacob Hunter MD]
Well, I definitely think there's a role for a multidisciplinary team. I would argue that every cochlear implant center in the world, whether it's adult or kids, it's a multidisciplinary team. It's definitely not as formalized as what we have with Children's. We have another partner, Ken Lee, who also implants children who's our pediatric program director, really thinks it's a strength of what we have at Children's. But it's definitely not as formalized as that. The audiologist and the three of us are in close communication every single patient and throughout the week regarding these patients, but we don't have that extensive social work discussion.
[Jacob Hunter MD]
I like to see a family member with a patient, whether that's for hearing loss or anything else, understanding that I might tell the patient one thing and they might not recall that. That goes for all medical issues. I think my parents really taught that, reinforced that with me, to understand that the patient might not remember everything you say. So I would mention or add that I think their family is also a part of that team. So, again, not as formalized as what we have at Children's, but working with audiology to figure out what would we recommend coming from a team front to say, "Listen, do we think a cochlear implant's in your best interest? Do we think maybe you should try hearing aids? When should you come back if you don't qualify?" Things of that sort. So, again, I would argue it's still multidisciplinary but just not as formal as what you're used to at Children's.
[Ashley Agan MD]
And do you do any formal cognitive testing, or is that only if you're concerned about that? Because you have a lot of patients, elderly patients, and I feel like there's a gray area before things are very obvious, like if a patient is very confused and there's obvious signs of memory loss or dementia or other things, you can pick that up, but then I feel like there's time leading up to that where unless you really test for it, you could miss that.
[Jacob Hunter MD]
I would love to test everybody for a cognitive screen. But my dad taught me when I was young, money doesn't grow on trees, and so we can't do that.
[Gopi Shah MD]
Did you have an Indian father? No? My dad said the same thing. Okay.
[Jacob Hunter MD]
Except I remember finding him a card one time where I found the money tree and gave it to him. He said, "Clearly, this is made up." I am running, I guess, a research study that is looking at the role of cognition in hearing loss, so if they're interested in participating, we do administer the MoCA, the Montreal Cognitive Assessment, which isn't perfect but it's definitely a, I guess, next generation outside of the Mini-Mental, if you recall learning that from med school. There's also a hearing impaired MoCA, but, again, these are only patients that qualify for this study. This has been done at a number of other centers, and I do think it might become more prevalent as we continue to move forward for the reasons I think you highlight, to understand the link between hearing loss and cognition. But it's a small fraction of our patients that are getting it. We are talking about maybe trying to change that a little and trying to figure out a solution without that proverbial money tree, but not everybody gets that cognitive screen.
(6) Imaging for Cochlear Implantation and Contraindications
[Ashley Agan MD]
Interesting. And when you have decided that a patient is a candidate for implantation, I assume everybody gets some sort of imaging, and is there any imaging that would be a contraindication to implantation?
[Jacob Hunter MD]
So I was trained to get a CAT scan and an MRI, and there's-
[Ashley Agan MD]
Oh, both.
[Jacob Hunter MD]
There's debate on that. I know my partners get an MRI. Now, I'm starting to just do an MRI preoperatively because I actually like getting a CAT scan postoperatively. But to speak to the MRI, you're looking for pathology, whether it's on the balance nerve or the hearing nerve, that would I don't want to say preclude implantation and it's not an absolute contraindication, but say it's something that we need to monitor or watch. It might dictate that we implant the other ear. Depending on a patient's insurance, if they do have what we call retrocochlear pathology, they are not a cochlear implant candidate in that ear, patients can still get an MRI now. Every single implant that's available in the US we can place and patients can get an MRI postoperatively, but like dental fillings, there's quite a bit of artifact on those MRIs because of the metal in the implant. So anything that needs close surveillance, it might mean we got to implant the other ear so you can evaluate it a little bit more. But there's-
[Ashley Agan MD]
Surveillance meaning if you had an acoustic neuroma or something, is that what you're saying?
[Jacob Hunter MD]
Or any other tumor perhaps, yeah.
[Gopi Shah MD]
In terms of imaging, the rule of thumb for me when I was residency, fellowship, whatnot was MRI was always good to check out the nerve, the cochlear nerve. Can you go a little bit into what you like about MRI and what you like about a CT or what you would find on each one, just for maybe our listeners who are in training, who might be a bit more curious about those questions.
[Jacob Hunter MD]
So in an adult, I'm looking at the MRI for, again, retrocochlear pathology, specifically looking to see if there's a vestibular schwannoma or a cochlear schwannoma or anything. You can have a meningioma that would dictate maybe one ear is better than the other. From a CT perspective, again, the focus of the CT is the bony anatomy, so I try to ... I'm not the best at this, and this is kind of ... I don't think many people do this. But I actually, depending on the brand I might place, I like to measure the actual size of the cochlea because then that would help dictate the type of electrode I might use. Some of my research has actually been able to demonstrate that you can still measure that with an MRI. It's a little bit rough around the edges, but I can still get that information from the MRI, and that's why I like to get the CAT scan postoperatively, because then I can essentially assess the implant in the cochlea. So I can calculate the insertion depth, I can understand perhaps the coverage of the cochlea, looking at where maybe certain frequencies might line up.
[Jacob Hunter MD]
But the CAT scan, definitely if somebody had surgery before, if somebody had chronic ear-related issues, I'm getting a CAT scan preoperatively generally to help understand that map, if you will, that bony anatomy and understand what I might be uncovering. But many time these patients come in, and I think that's why a lot of the residents like these cases, because these patients never had an ear-related issue. The mastoid's pristine, well-aerated. It's good teaching perspective as opposed to a hot mastoid or one with a cholesteatoma or a sclerotic one. Nevertheless, you do encounter those, but many times it's a normal T bone.
(7) Comparison of Cochlear Implant Devices
[Ashley Agan MD]
And you mentioned briefly different brands or different electrodes. I think that maybe this is a good segue to talk about that. What are the major brands and the differences between the different electrodes, and who decides what's best for which patient?
[Jacob Hunter MD]
So I guess I would start by saying I think the patient decides what's best for each patient. I think it's my job to provide them as much information as possible to help them make that decision, but I try, and I think the three of us try, I know the three of us and our entire group try to let the patient decide. In the United States as of today, there are three companies. We'll go in alphabetical order, Advanced Bionics, Cochlear, and MED-EL, that manufacture cochlear implants for patients to select. The differences are subtle, but the length of the electrode is slightly different between the manufacturers. The type of electrode, so sometimes the electrode might be pre-curled, so it might be ready to already go into the cochlear curved. Obviously, if it's curled, you can't place that through a small hole, so it's either with a wire in it or in a little sheath that keeps it straight, so then you can insert it and either remove the wire or have it come out of the sheath, and so then it curls around the cochlea as it goes in.
[Jacob Hunter MD]
Then, between the three manufacturers, how they have those electrode contacts. One, they might have a different number of electrode contacts, but then also how the electrode is designed, so some of the electrodes have a little more stiffness to them. Others are a little more ... I use the example when I'm teaching some of the residents, it might be like a cooked piece of spaghetti. Those are probably the nuances between the electrodes. Then you have processors, and so the processors, for the most part, are the same. There are sound coding strategies that are essentially ... I don't want to go in too much detail because I'm still trying to learn more about that, but they're kind of similar between manufacturers, but there are significant differences as well. Ultimately, it's just out of my league in terms of the engineering behind that. I wish I could understand it, but I'm, as I said, trying to learn more.
[Jacob Hunter MD]
But, again, it goes back to the patient. What does the patient feel comfortable with? Obviously, if you know somebody with a cochlear implant, they're going to probably know that brand and feel that brand's best for them. Some patients come in, obviously, with hearing aids already, and so some of the companies have a relationship with the hearing aid companies so that you can have a cochlear implant in one ear and then it will communicate with your hearing aid in the other. MED-EL, though, would argue that theirs is compatible with all hearing aids. In all three companies, it's essentially compatible with all hearing aids. It just might mean you've got to buy extra devices, a third device that links the two. So that can be a big issue for patients.
[Jacob Hunter MD]
Two of the companies allow something that you don't need to wear over the ear. It's just a slightly larger thing that stays back, and that is, I think, a big selling point for some patients because they're just sick and tired of the hearing aid behind the ear. Nowadays, especially with the fact that all three are MRI safe, the nuances are small. So, again, we leave it generally to the patient.
[Ashley Agan MD]
And do you have a preference about length, like conventional versus hybrid lengths of electrodes?
[Jacob Hunter MD]
I do-
[Gopi Shah MD]
And can you go into the differences, just for our listeners? Conventional versus hybrid, what is the difference?
[Jacob Hunter MD]
So the idea behind the hybrid was that your cochlea is organized in a tonotopic fashion, so while the cochlea is ... I think most of us are aware it's a spiral. It's a cinnamon roll. You can unravel this, and it's a straight line.
[Ashley Agan MD]
That's how I eat my cinnamon rolls.
[Jacob Hunter MD]
Really? You unravel them? Oh, I don't. I just bite through them.
[Ashley Agan MD]
Oh, yeah.
[Gopi Shah MD]
I like mine unraveled, too, but-
[Ashley Agan MD]
You, too, Gopi?
[Gopi Shah MD]
I do because I feel like it's crunchier on the outside, and then I like the change in ... Kind of like the frequency, a change in the-
[Ashley Agan MD]
And it lasts longer.
[Gopi Shah MD]
Yeah.
[Ashley Agan MD]
You know, you can savor it.
[Jacob Hunter MD]
Well, technically, it's not exactly like a cinnamon roll because it's not on a flat plane. It's much more tiered. But the idea is that you unravel it, it's a straight line. So I personally have a preference of a longer electrode. If I had to choose, I like the length, and the rationale for that is better coverage of the cochlea, and so that with the idea with the hybrid is that you have a shorter electrode, you might not be fitting that entire cochlea. Many patients can actually, and this is where the criteria is expanding, many patients can actually still have a hearing aid and wear a cochlear implant. This gets a little tricky. This is a concept called residual hearing, and I struggle over how to counsel patients about this weekly.
[Jacob Hunter MD]
But say patients come in and they have good low frequency hearing, great low frequency hearing. That's great, but that doesn't necessarily mean that they're benefiting from their hearing aids. They're struggling in communication. They're struggling with their hearing aids. So you can actually have someone that qualifies for a cochlear implant but has great, excellent low frequency hearing. You can place an electrode in the cochlea to stimulate the high frequencies to get them the benefit that they need in the high frequencies, and then you can turn it off for the low frequencies. I have one patient that doesn't even need a hearing aid. He actually hears naturally in the low frequencies.
[Jacob Hunter MD]
So the idea behind the hybrid is, with the understanding that the low frequencies are located at the top of the cochlea, what if you put the wire in partway? You put the wire in partway, stimulating the frequencies the patient needs to get the electric benefit, and then you leave the apex of the cochlea untouched. You try not to traumatize it so you can preserve that hearing and so that after surgery we can fit them with a hearing aid. More often than not, most people have to have something, that you can fit them with a hearing aid for those low frequencies. So the idea behind the hybrid is by limiting the insertion of the implant into the cochlea, you're minimizing the risk of trauma to the top end.
[Jacob Hunter MD]
We've kind of gone away from the super, super, super short electrodes. I do have a colleague in Germany that partially inserts a normal length electrode partway in cases of those, and then say the patient loses those low frequencies at a later date, will stick it further in at another time. But nowadays we know we can still place long electrodes and still preserve those low frequencies, not always, and you can still do it. I personally like long electrodes, but there's definitely a debate. I mean, Coke versus Pepsi, there's no right answer to that, I should say.
(8) Surgical Technique for Cochlear Implantation
[Gopi Shah MD]
So can you tell us a little bit about the surgery itself, the insertion approaches, and if you use ... Is there a different approach or surgically do you do anything different for the hybrid versus the conventional electrodes?
[Jacob Hunter MD]
So the surgery consists of a bread and butter procedure that I think every ENT goes through for training, is a mastoidectomy. Then we drill a small tunnel, a window into the middle ear, and that provides us kind of a sitting on the front step, the door into the cochlea. So there's a small window there, what's called the round window, that literally looks like an eardrum. You can see the little annulus. It's a little nuanced, but it's technically shaped like a Pringle chip, not quite as parabolic, but it's technically not like your eardrum. So I was trained and I strongly believe in placing the electrode into the round window because, technically, the cochlea is actually made up of ... As I said, it's one straight line, but it's technically like in that straight line, there's two compartments. The compartments talk to each other at the very top or the fluid exchange at the very top. But we like to place it in this one specific compartment called the scala tympani. So when we know we insert in the round window, it's 100% it's going in the scala tympani.
[Jacob Hunter MD]
Sometimes, that round window's difficult to see. Sometimes, it's angled. Sometimes, there's pathology. So sometimes surgeons will do what we call an extended round window, so they'll partially insert it through the round window but actually use the drill to open the bone right next to it so that they extend the round window, so to speak. Then there's some surgeons that prefer what we call a cochleostomy. They drill a hole on the outside of the cochlea to place the electrode. Again, there's no right answer. Some people believe strongly in their way, but those are the three approaches.
[Jacob Hunter MD]
To speak to those patients, though, with the residual hearing, those patients that maybe might be what we would be able to acoustically aid after surgery, I don't use any special products, I should say, but I like administering steroids during the case in the sense of they get an IV dose ... And most patients get this through anesthesia, but I will actually bathe the middle ear in middle steroids, allowing absorption of the steroid through the round window and/or the oval window, hoping the steroids get into the cochlea, minimizing post-operative inflammation. I know of a colleague in California that actually injects the middle ear with steroids at the beginning of the case, like 30 minutes before, so maybe it has a little more time to get in there.
[Jacob Hunter MD]
Then, when we're drilling on the cochlea, I turn the drill speed down to 10,000 with the understanding that I could still cause acoustic trauma if I drill at a high speed. So drill slow and then slowly insert the electrode into the cochlea. We're talking slow. I will literally have the resident count out every five or 10 seconds with the goal of inserting it somewhere between a minute and a minute 30. I don't know if that's the correct speed, but as slow in speed ... I don't want to just jam it in there. So we call this, that grouping there, that technique, a soft surgery approach. There is an argument that everybody should be given that approach. I'll admit, I don't necessarily do that for everybody, but it's kind of a soft surgery technique with the idea of trying to preserve the natural structures of the cochlea as best as possible.
[Gopi Shah MD]
Can you tell us about the Kenalog or, excuse me, the steroid, what kind of ... I assumed it was Kenalog, I apologize. What kind of steroids do you use when you bathe the middle ear?
[Jacob Hunter MD]
I always ask for a preservative free dexamethasone. I honestly don't know if that makes much of a difference. The hope is that it's with passive diffusion entering the cochlea and allowing minimization of fibrosis or scarring afterwards. I have a colleague in Miami that's working with electrodes that actually elute steroids after they're in, and then there's some data to suggest that putting steroids in and around the surgery, I should also add I also send the patient home with a steroid course, short steroid burst, really, that administering steroids at the time of surgery increases the chance of maintaining the residual hearing in the long-term. Because we can still preserve the residual hearing at the time of surgery, but then there's a risk that they could, one, naturally lose it or a slow scarring might occur in the cochlea and so they might lose that hearing naturally or they might lose the hearing in the cochlea at a much greater rate than they naturally would because there's this foreign object in there. The data suggests maybe by administering steroids, you might minimize or reduce that chance over the long-run.
[Ashley Agan MD]
And you and I were talking about this recently, and you mentioned that in the future it is likely that we'll use robotics to help insert electrodes, I assume to minimize the trauma and make it to where it's this perfect insertion. You could measure everything beforehand and just kind of say, "Go." Talk to us about that.
[Jacob Hunter MD]
Oh, yeah. I mean, when you think about when you're inserting that electrode and you're trying to do that slowly, it might look smooth and steady to your eye. But I remember doing a study where I was one of the trial participants in fellowship where they measured the forced insertion trauma, and some people jackhammer it in there, and you can just imagine that's not good for the cochlea. So there's a couple of people in the US, or, at least, I can think of one, that have created or are working with a robot to insert the electrode. As far as I'm aware, it's getting everything set up and then they use a computer, a robot to insert the electrode.
[Jacob Hunter MD]
Then I have colleagues in Europe, as well as one of my mentors, Rob Labadie at Vanderbilt, who are working on robotic cochlear implantation, and we're talking from outside of, okay, a skin incision, once the skin incision and the bone's exposed, having a robot do that. That's very, very preliminary, but it has been done. There are people in the world that are walking around with an implant that was placed or the surgery was completed by a robot. When that will become commonplace, I don't know, but that is ... I guess robots were always taking over the future, right?
(9) Potential Complications of Cochlear Implantation
[Gopi Shah MD]
So before the robots take over the surgery and start counseling our patients, can you tell us how you counsel patients in terms of about the surgery, postop management, short-term, long-term, potential complications, or things to consider?
[Jacob Hunter MD]
So I go through the risks and benefits, and so it's pain, bleeding, and infection. We talk about the risk of dizziness, short-term and long-term, the risk of some taste changes because of the chorda tympani nerve. That tunnel that we drill or that window that we drill to gain access to the middle ear is right between the chorda tympani nerve and the facial nerve, and so then we also discuss the possibility of facial nerve weakness. Then by drilling the ear by near the brain, we need to talk about spinal fluid leak risk. We also add that patients might not like the implant. I feel our patients or my patients that are frustrated by their implant, I think that's kind of on me and our audiologist to maybe we didn't do as good a job of counseling that patient and preparing that patient. I think that's part of my job, to allow them to have appropriate expectations to understand what's the post-implant hearing life going to be.
[Jacob Hunter MD]
And so I kind of joke with them, my job is to get the implant in there, and it's an hour, hour and a half surgery, and they're able to go home the same day, and pain is generally pretty minimal. The hard part is actually once you turn it on. It's not like putting on a hearing aid and, boom, the world opens up. It's almost like relearning how to hear. So we generally counsel that it takes about three to six months to maybe reach the benefit or to exceed the benefit that you're getting from the hearing aid, and that's also dependent upon what their hearing was before. If someone comes in that literally is not getting anything, anything, you turn it on, they should do pretty well pretty quickly, and how you define well, what was better than before. But I tell them the hard part is after surgery, using it, getting stimulation, whether that's talking with your family or an audiobook to the implant, listening to relearn how to hear, and that can take time.
[Jacob Hunter MD]
I also warn patients if they're tired, that's a good sign. It means that their brain was working hard that day, and I don't think that tiredness will persist. Not that there's pain postoperatively, yes, immediately, but long-term, but no pain, no gain. If you're not struggling with it, you're not going to reach the benefits with it. So it can take time, but to give it time and be patient, and the more they work with it, hopefully the better the outcome. I think that answers your question.
[Ashley Agan MD]
How long are they expected to last? Let's say you're implanting someone that's 50. Do we expect their implant to be good forever and-
[Jacob Hunter MD]
I mean, there's always a risk that the implant might malfunction. It's very, very, very, very low. So I remember correctly, I think in adults it was approved by the FDA in '84, in children around '90. There are people walking around with implants still from that time. Yes, I've had a malfunctioned implant. Most, I'd like to think all cochlear implant surgeons have had to take out an implant that wasn't working. Sometimes, that happens immediately. Sometimes, that happens over many years. But to go back to your example, a 50-year-old, I would tell them to expect to wear it the rest of their life, to have it the rest of their life.
(10) Perioperative Management of Cochlear Implant Patients
[Gopi Shah MD]
In terms of the older population, so started having more trouble hearing at 65, got hearing aids at 73, and now they're 80, what perioperative factors are unique to this population?
[Jacob Hunter MD]
That's a fair question. I know cognition is the key here. Obviously, as we get older, more of our patients have other medical problems. I did a project in fellowship where we looked at, and this was mainly through the experience of my mentor, David Haynes and a colleague up at Mayo, Colin Driscoll, where they had patients who'd stopped their blood thinners, and there were significant consequences for stopping their blood thinners. So both of them had realized why stop the blood thinners, just continue the surgery and you deal with a little extra bleeding during the surgery, maybe a little bruising. Sure enough, we showed that that's safe.
[Jacob Hunter MD]
You asked what I do ask about. I actually do ask about blood thinners if we're going to surgery, and I remind the patient and their family, "Continue them. Don't stop them. The risks are too great." So, from that perspective, bleeding, I tell them to continue blood thinners. I would love to be able to do it under local anesthesia. I've tried to talk with our anesthesiologists about that. They are not game, but I do know there's people in the US and I know of somebody in Finland. I think he does everybody over 80, it's under local anesthesia. But our anesthesiologists, the heads turned away from the anesthesiologists. They're obviously light, or I don't want to say light, but if they need to access to the airway, it's a little difficult, and so our anesthesiologists don't feel comfortable doing it for our patients.
[Jacob Hunter MD]
But those are the two big issues from a perioperative perspective, and I might be missing something, and I might be not paying attention to the anesthetic concerns as much, but I think another big factor, and this has to do with the postoperative issues, is dealing with this small little device that has small buttons and a lot of little pieces to it. As we get older, our dexterity might not be as good, and that is an issue for some patients. I know for our audiologists it can help them persuade perhaps a patient from electing to choose a different manufacturer, because the audiologists feel that it just requires less fiddling, I think, from an audiologist's perspective.
[Gopi Shah MD]
Are there more concerns about wound healing at the incision site in this age group or pressure ulcers from the external process or that they wear?
[Jacob Hunter MD]
I have not, and maybe I should be worried about the wound healing. Obviously, asking about any other medical problems or if they've had surgery before, and if they've mentioned something, that obviously plays a role. For some older patients, the skin can be kind of thin, so we do see occasionally that the skin generally would demonstrate redness and erythema and that sometimes there's erosion. We do pay attention to that, and you do see that in older patients. I saw a guy, this was right when we reopened after COVID, where the entire implant was exposed, and he was using it, but I think it was just he was living on his own. I think he was in his late 60s, and the son felt bad because they just weren't paying that close of attention. It's rare, but it is something that we do see occasionally. It is a magnet that allows the external device to connect to the internal device, so in those patients, it's maybe reducing that magnet strength, maybe putting a pad on there to protect the skin. It's rare, but it is something that we do pay attention to and look for.
[Ashley Agan MD]
Yeah. I feel like a lot of my older patients just are ... When you start talking about surgery, that just sounds very ... That's not an option maybe. I think they're just nervous about the implications of having surgery when you're 85.
[Jacob Hunter MD]
Yeah, we actually have a paper coming out, it should be coming out any day, that looks at the barriers to implantation on a number of levels. We actually administered a survey to patients about why they did and did not elect to go through surgery. To break the numbers down, and this is very crude, but for every four patients that come to see us for an evaluation, three qualify, and for the three that qualify, two end up proceeding with surgery. So we wanted to explore why that percentage of patients did not proceed with surgery. You're right, anesthesia and surgery are concerns. We had a small sample size, but that was surprisingly not the number one issue. A big motivation was communication that forced people to do the surgery and then concerns about their benefit with the implant. They were worried about being worse off, if I can recall, is the number one issue, not to ignore that that was an issue, but not the number one issue.
[Ashley Agan MD]
So you're saying that the number issue is that people were worried that it wouldn't work and they would be worse off than-
[Jacob Hunter MD]
Yeah, another big issue is their concern that what if better technology comes out down the road, say, the stem cell regeneration. But I remember I was given ... Talk about an insulated world, but I remember my mentor gave me a book in fellowship that was a biography of Bill House, who's considered the father of cochlear implants. It was actually known in France in 1957 that they stimulated the hearing nerve, and this newspaper in LA wrote about it, and one of his patients saw this and comes to him saying, "Hey, can you do something about this," and he was like, "Oh," and looked into it more. This is then in the '60s, and this is where we are today. So reading his book, I know in the '70s when it was becoming a little more ... This is when these first implants were designed. There was big backlash on, listen, you're killing the hearing nerve. They're never going to hear.
[Jacob Hunter MD]
People were actively ... Very smart people, much smarter than me, are looking into stem cell regeneration. Maybe that will meet the robots, but hopefully that will be a reality soon. It's always like do you wait for something better or do you go for something now. So that is another issue, is, well, concern that they're missing out on something down the road, which I know, I think, Gopi, you've encountered and discussed with me. You see it more, I think, in the pediatric population when you have a parent that's talking about this, especially hearing parents with a child that can't hear. I can't imagine what goes through their heads making these important life-changing decisions for their kid who you hope you're making the right move for them.
[Gopi Shah MD]
No, for sure. So just going back to surgery, are y'all doing bilateral in adults like you do in children at the same time?
[Jacob Hunter MD]
I very, very, very rarely do that. I actually have a bilateral guy coming up who unfortunately lost his hearing suddenly back in September. There's a medical issue going on that they don't have an understanding of what's going on, but he wants to do bilateral. But it is a very, very rare occurrence that we do it simultaneously. There are some people that do elect to get the second side done at a later date. Most people don't elect to do that.
[Ashley Agan MD]
Yeah. So most people, you're implanting the worst hearing ear and-
[Jacob Hunter MD]
We do the worst hearing ear, yeah. I know there's research. Rene Gifford published this a year or two ago, noting that the patient knows best. The patient, if they think they want the second side, then it makes sense to do the second side. The second side gives them better ... They're able to localize. Two ears are better than one. That's kind of the big one. I think it's 10% of our practice proceed with that second.
[Ashley Agan MD]
We've talked a lot about the patient that presents to you and the indications and the surgery. Before we wrap up, I wanted to just ask you to talk to us a little bit about your research in disparities to access. You and I talked a little bit about this recently, about how when you look at people who are getting cochlear implants, that it doesn't reflect the population in there.
[Jacob Hunter MD]
Yeah. So Anthony Tolisano, so our former fellow, helped me put together our adult cochlear implantation database a few years ago. It definitely provided us a perspective of the forest, taking a step back. We found that 87% of the patients that we implant are white, yet 47% of the people that live in our metroplex are white, so our practice does not represent our community. This isn't unique. Vanderbilt published that 88% of their population, their cochlear implantation is white. There's the cochlear implantation coordinator at Cincinnati who's written about the barriers to the Black community towards physician mistrust and that that is a big impediment. Carrie Nieman at Hopkins is actually looking into going out to the community to change those barriers, to change people's minds about hearing healthcare.
[Jacob Hunter MD]
So we've looked at our institutional practice. As I mentioned, it doesn't represent our community. We actually found that minorities are more likely to qualify for an implant than white patients, which tells us that those patients are coming in even later than white patients. They're not getting in to see a doctor, they're not getting a hearing aid or, sorry, a hearing test, so they're coming in and I think it's 92%. So here I told you, overall, 75% of people that come in for evaluation qualified. For minorities, it's actually 91 or 92, so that means for white people it's less than 75, hence the average. But then, once they do qualify, we find that they are much less likely to proceed with surgery than white patients, so there's, again, barriers to why is that.
[Jacob Hunter MD]
There's data that we have under review that's looking at the state-wide perspective in Texas. Texas has a nice, diverse patient population. Houston's tremendously diverse. So it's interesting to see how the per capita rate of implanting different ethnic groups ... Whites are significantly greater represented than the other ethnic groups. While I would love to have answers regarding why that is the case, I do think the first step is, one, identifying these discrepancies and what we're doing now, talking about these disparities, and then trying to figure out ... I think Carrie Nieman is doing ... It's interesting to hear what she's doing in Baltimore to try to correct these, and that's, I think, going out into the community and trying to take down those barriers. That clearly doesn't happen overnight. It's going to take time.
[Gopi Shah MD]
Yeah. I think I agree. Identification is the first step in bringing all of this information to light. It would be cool to collaborate and see what we have on the pediatric side as well, Jake.
[Jacob Hunter MD]
Yeah. Well, the pediatric practice, it's definitely different than the adult practice, and for a good reason. I think the more we talk about it and the more we implant, I think that does increase awareness. Hearing healthcare is a big issue, and it's maybe not reaching everybody, and I think what you guys are doing here is awesome, not only for today in hearing healthcare but for otolaryngology and medicine and women in medicine. The more we get the word out, the more things will change, so I think it's a good thing. So that's, I guess, about it.
[Ashley Agan MD]
Awesome. Well, thank you for being here. This was an amazing talk.
[Gopi Shah MD]
I learned a ton.
Podcast Contributors
Dr. Jacob Hunter
Dr. Jacob Hunter is Assistant Professor of Neurotology in the Department of Otolaryngology-Head and Neck Surgery at UT Southwestern Medical Center.
Dr. Gopi Shah
Dr. Gopi Shah is a practicing ENT at UT Southwestern Medical Center in Dallas, TX.
Dr. Ashley Agan
Dr. Ashley Agan is a practicing ENT and assistant professor at UT Southwestern Medical Center in Dallas, TX.
Cite This Podcast
BackTable, LLC (Producer). (2021, February 2). Ep. 15 – Adult Cochlear Implantation [Audio podcast]. Retrieved from https://www.backtable.com
Disclaimer: The Materials available on BackTable.com are for informational and educational purposes only and are not a substitute for the professional judgment of a healthcare professional in diagnosing and treating patients. The opinions expressed by participants of the BackTable Podcast belong solely to the participants, and do not necessarily reflect the views of BackTable.
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