Cliff A. Megerian, MD, FACS, and Gail Murray, PhD, perform a bilateral sequential cochlear implant procedure on a three-year-old male. This procedure is done on individuals with severe to profound sensory neural hearing loss or defenses who do not benefit from traditional hearing aids.
Video recorded at University Hopsitals, Cleveland, Ohio, 2008. GAIL MURRAY: Today we're going to show you a bilateral sequential cochlear implant procedure on a 3-year-old boy. This procedure is done on individuals with severe to profound sensorineural hearing loss, or deafness, and only in those who do not benefit from appropriate or suitable hearing aids. We're going to show you the preparation for the procedure, a metastoidectomy, a cochleotomy, and the insertion of the cochlear implant. And introduce him now, Dr. Cliff Megerian is our surgeon. CLIFF MEGERIAN: We're very excited to be here today. This is an adorable young man who we're excited to take care of. He, as you know, had an implant on the right side. And what we're going to be trying to do is really per the family's request, go ahead and allow him to hear from both ears. Because you know, it's pretty natural to hear from both ears. And as implants have become more and more commonplace and more and more safe and reliable, it's become clear that hearing with an implant is similar to hearing with normal, natural ears. It is some advantages to hear from both ears. So we're gonna take care of him today. And one of the things that we're going to do today is try to concentrate very hard on some unique things we try to do when we're doing an implant surgery when we already have an implant on the other side. So I'll talk through some of the steps that we do. The first thing we always do is we don't use unipolar cautery so as not to injure the implant on the other side. For the most part, the surgery will be as if we were doing a single implant. In other words, we are making our incision-- I'll take the 15 blade again-- in such a manner as to leave the periosteum down onto the bone. OK. And I'll take a pick ups please. And we are going to be raising these flaps that will help us at the end close in the most inconspicuous way. So what we're looking at right now on this field is the periosteum over the mastoid cortex. And we have a little random bleeding here we'll take care of with the bipolar. And we're going to go ahead and put it in what we call self-retaining retractors. The next step is to go ahead and take-- again, normally we use a cautery, but in this case, since we have an implant on the other side-- we're going to use a sharp dissection using this blade to create a incision through the periosteum, up into the temporalis region. And this will allow us to dissect very nicely right down onto the bone, and create flaps that we can use. So this is what we call sub periosteal flap that we're developing. And the landmark that we want to take this flap to anteriorly-- and I'll show it to you here in a second-- is the external auditory canal. As we put in one of the tines of our retractor, you can see the extra auditory canal running away from us right here. Pick ups. And then we're going to go ahead and raise flaps going posteriorly so-called, sub periostial flaps posteriorly. So the first step of a cochlear implant is to go ahead and perform a mastoidectomy. And I'm going to go ahead and get started here. We use a high-speed drill. And in these little kids, the mastoid is fairly small. And as soon as you begin drilling, you will be able to see the air cells of the mastoid. You want to take your time, and make sure you have plenty of irrigation. And immediately as you open, you'll be able to fall right into the mastoid cavity. Unlike a standard mastoidectomy that you're performing, you don't have to really remove every air cell within the mastoid. It's really important to find really one critical structure, which we're starting to see right now and I'm going to point out, which is called the horizontal semicircular canal. Let's roll the patient away from us, please. Let's roll the patient away, please. Good. Keep going. Keep going. Perfect. All righty. So what we're going to do now is I'm going to point out-- you can see how quickly really in pediatric patients the mastoid opens. And as you see, we're going to be pointing out our horizontal semicircular canal, which is right here. Why don't we take a rosen so I could point that out. That's our first landmark. While we're doing that, why don't we switch to a number three drill. And right here, you can see the horizontal semicircular canal. People sometimes wonder why you have to open the mastoid to do a cochlear implant, if in reality, you're really working in the cochlea, which is visualized in the middle ear. Well, the reason it is that the mastoid allows us a pathway directly to the middle ear and the cochlea that bypasses and preserves the eardrum. And so when it's all said and done, you'll have a hermetically sealed implant. Now if we move our microscope back just a little bit, we're going to be able to see another important landmark, which is right here, called the incus. Let's take a rosen. Once you find this incus bone right here, you can follow the end of it right into the facial recess. Let's take the 3-cutter, please. One of the things that we like to do is we like to really thin out the bony posterior canal. Cause that's gonna allow us to fall right into this facial recess area. GAIL MURRAY: Dr. Megerian, one of the patient's concerns are often whether the surgery will interfere at all with the function of the facial nerve. Can you comment on where that is in relation to where you're drilling right now? CLIFF MEGERIAN: Right. So what Dr. Murray is getting at-- and what I was alluding to earlier-- is the facial nerve is a very important structure which runs right through the middle ear in the mastoid. And part of the job of the surgeon is to avoid injury to it. One of the best ways is to identify the facial nerve to avoid injuring it. The other way is to open the facial recess directly. And as you're opening the facial recess, know where the nerve is going to be in that relationship. So one of the tricks that we do here is we find the incus, which is right here. Let's turn the water down just for a second. Here's the incus. And then what we're going to do is we're going to follow the end of the incus, which is right here. This is called the short process. And that points directly into the facial recess, which is an area where we have a pathway going directly above. We'll take a 2-diamond. Directly above the facial nerve and under the ear drum. So as we start drilling, we're going to show you the region where the nerve was going to be, and where we could safely go above it to get into the middle ear. OK. So this is a number 2. This is a diamond drill. And a diamond drill is unique in that it doesn't have fluted edges. So it is much easier on soft tissue in the event that we get close to the nerve. What I want to show everybody is-- go ahead and get me a little bit more irrigation. Chris. The facial nerve is right here, running right in this area right here. You can kind of see through the bone, there is a redness. Once we see that, we can come right above it into our facial recess. And this is a very important step. Because once we get into the facial recess, we should be able to directly visualize the important structures of the middle ear. And more importantly, the round window, which is really the area that we're trying to target. OK. So one of the ways that you know you're going in the right direction is you all see through here, you see a little-- what looks like a little tendon. And that's the tendon of the stapes. OK. Let's take a 5-section. So you kind of know you're heading in the right direction is when you've gone through the facial recess, and you see that really nice-looking tendon there. And that's the tendon of the stapes, so-called stapedial tendon. And now what we want to do is we want to carefully go above the facial nerve, which I pointed out is right under here, but s hit it. Open the facial recess until we can see what's called the round window. And we're going to see that together here in just a minute. That's the window that opens us into the cochlea. What you have to be very careful about is not putting your burr or your drill on the facial nerve. Because our facial nerve, as I mentioned, right here is protected by bone. But if you didn't really have bone over it, you can injure that nerve with that turning of your burr. And now you can see the round window. If you look very closely. Let's take a 20 suction. You're actually going to see your round window. So we've done some of the most important part of this operation already is expose this round window, right over here. You can see this window. And there's a little bit of irrigation. You notice we irrigate during the surgery. The irrigation makes sure that we don't burn the bone. It helps the drill move faster. There's the window right there. You kind of see a half moon right there. And there's your stapes tendon. So we have prepared the opening. And in essence, when we open the cochlea, we're going to go right through this area to put in our electrode. But we've got a little bit more work to do. What do we have to do-- OK. Now the fun part is to take this-- this is a dummy implant. It's really silicone or silastic. And we want to fit this-- this is silastic. This is about the shape and the size of the implant. And we'll show it to you in just one more second. Let's make sure that we have enough room to put this in. And this is why we call it a dummy, because we're really going to be making some measurements, and making sure that it's where I want it to be. So we're going to pull back the temporalis muscle and fascia here now. Gonna pull this back here. And here. It's amazing how much room that you can have through this small incision. And it's really amazing how much progress we've made, I think, collectively as surgeons around the world, really, in making this a small incision, compared to before. And we'll take a sponge. What we're doing right now is we're exposing the area. And what we like to do is we like to work underneath the skin flap so that in the end, it's all covered back up again. And we like to expose-- relax a little bit. There we go. Expose this bone. This is kind of thin bone in children. And we have to make a little well here. Now one of the challenges that we have is that in children, this is very thin. In adults it's a little thicker. OK. You really need to let go just for a second. Let go just a second. And you need to pull, OK. There you go. Pull. Sorry. The challenge that we have in children is that sometimes this bone is very thin. And what you don't want to have is in an implant, is you don't want to see or feel the implant sticking through the skin too much. And so what we try to do is we try to make sure that we have a nice little pocket in the bone for this to sit. And this sometimes can be one of the more challenging parts, because what you're going to see very quickly is the dura. If I go up in power a little bit, you see one of the challenges of seating this implant in this young man will be that the implant will want to be protruding in this one part, because the dura, as you can see, is a little bit lateral. So what we can do is we can take a diamond burr and just gently remove the thin bone. Be careful not to injure it. And this dura's just going to sit down nice like that. You see that? This is kind of the winding down part. We're going to make a little trough between the mastoid cortex here and the implant receiver well here. We take a little cutting drill. You can see we have a very nice pathway right here. Sometimes you've got to be careful, the sigmoid sinus is running high. But in this case it's very nice. The next step for us is we kind of like to really secure our implant so it's not going to move. So to do so, I like to put sutures. And what we've kind of decided upon here is putting in sutures through the bone. So I take a number 1 drill and I make a little opening, and pop through. Same on the other side. And then we take a suture. I usually take a 2-0 nurolon suture that's already loaded here by Chris. And what I like to do is I like to bite in the back. Have you pull up a little bit like this, Chris. Sometimes you have to put your finger here just to feel, make sure you're in the right plane. OK. Let it get a little bit-- there we go. GAIL MURRAY: One of the questions that patients often ask when they present for a cochlear implant is what the success rate is for this type of surgery. And you can think of success in a number of ways. The first being what the reliability of the implant is in terms of the long-term longevity of the device inside the body continuing to function. And my response to these patients is that the implant's designed to last a lifetime. Once it's in, we do not ever expect to need to remove it and take it out. On the other hand, the part of the device that's worn outside of the body is something that we expect to change over time. CLIFF MEGERIAN: OK. You can come out. GAIL MURRAY: The external speech processor is something that is replaced as technology advances and improves, and provides better function and actually better outcome in performance over time. So while we never anticipate that the internal implant will ever need to be replaced, the external equipment will be replaced as advances occur. CLIFF MEGERIAN: Let's roll the patient away, please. GAIL MURRAY: The other thing to think about in terms of success rate is the actual performance of the patient with the implant once it's applied. And it's important for us to set realistic expectations for the patient prior to the surgery based on their individual medical history, because there's a broad range of post-operative outcomes and post-operative performance. This is often associated with the etiology for the hearing loss, the duration of deafness, the amount of language or time. Say, in an adult with an acquired hearing loss, the amount of time they heard prior to losing their hearing. In the case of a child like this, our goal is to implant the child as young as we possibly can so that they have as much exposure to sound during the most important years for speech and language development, which is generally thought to be between birth and the third or fourth year of life. So. CLIFF MEGERIAN: I'm sorry to interrupt you, Gail. I just want everyone to see as you're talking, now we've gone back to our facial recess. And again, I'm going to point out the structures, because we're getting ready to go ahead and make our opening into the cochlea. And this is really a beautiful anatomical view. You have your facial recesses right here, this opening. You have your horizontal semicircular canal here. You have your incus right here. Your incus is moving right here. And you can see your stapes moving in and out. And as you look downward, you have right here, is your round window area. OK. OK. We'll try it again. Let's take a pick, please. I just want to show some of this really nice anatomical structures that we have. This is what you want to see as you're getting ready to do your cochleostomy. You want to see a nice trough right here. You want to see your horizontal canal. You can see your facial nerve in its horizontal segment right here. You can see your incus. And you can move your incus. And you can see your stapes moving. And then inside you can see your round window right here. Now our goal is to go ahead and make what's called a cochleostomy, which is an opening. And I'd like to make it right over the lip here, and make sure I open to the scala timpani. We're going to go ahead and take a 20-suction, which I have in my left hand. And a number one diamond drill. And Chris will irrigate for me as we're drilling. And we'll move the pedal over a little bit. One of the things that's very important as you're doing this is to make sure that your shaft of your burr is not on your facial nerve area right here. There's a quick way to injure the nerve. And if you make your opening large enough in your facial recess, you have plenty of room to avoid injury and avoid that happening. Make a little divot there. Make sure we're centered here, so everybody can see. GAIL MURRAY: Again, what's the size of the drill you're using? CLIFF MEGERIAN: This is a 1-millimeter diamond drill. And you can now see the endostium, which is the inner lining of the cochlea. And there we have it. You don't want to suck too hard. But you want to be able to see-- there we go-- that we're in the cochlea. And you can see that very nicely. OK. And we can actually see the basilar membrane, so that we're for sure in the scala timpani. And here is the basilar membrane right here. We're gonna go up in power a little bit. Take a little suction here. But not suck too hard. This is a very nice important view. Let's take a pic, please. So we can all see. Let's take a pic, please. You can see right up here, is the basilar membrane up top. Here is the round window. And then there you're going to see going away from us. There's a of lymphatic fluid. And the first turn of the cochlea, the so-called basilar turn. You go back a little bit, maybe it's a little better view this way. What I like to make my cochleostomy between the stabes and the promontory. And I've always able to preserve that basilar membrane right here. Now don't suck too hard. But you know you're within the cochlea, because as you get a little bit of fluid, you can see the basilar turn going away from you. That's really a perfect picture. And he's going to have a perfect insertion, I think. We hope. OK. The implant device is gonna come under my sutures that I've put in. Deep underneath the temporalis muscle. Slide back into the slot I've created. And it's going to sit right in perfectly like we see it. Now we're gonna pull my sutures. And my sutures hold it in just perfectly. OK Now we're going to tie these down. And that's going to give us a very, very nice seating for this young man. OK. So we'll tie these down. And we're going to have Chris just go ahead and-- perfect. And we'll take our scissors. And one more tie down here. Just holding our leads. So they don't move and migrate. You can see that's holding the leads over the trough. OK. So we're moving right ahead. The next step is we're going to go ahead and put our extra temporal lead. And maybe Dr. Murray can explain this. But the implant actually comes with two different electrode leads. And you can kind of see them here. One lead is designed to be a ground. And we like to place that underneath the temporalis muscle. So I'm going to make a little pocket here for that. We'll take a pick ups and a periostial. Periostial, please. GAIL MURRAY: While he's doing this, maybe we can flip to the bone fluoro animation, and actually give the audience a view of what-- give the audience a view of what it's like to see the implant inserted in live action. So you're looking outside the wall of the otis capsule. Dr. Megerian has referred to the basilar membrane, which has the modulus, or Houses the modiolus. And you can see as the implant is being inserted, the electrode is actually advanced off of a stylette that remains stationary, that initially keeps the implant straight and rigid. But as the implant is moved off the stylette, the electrode smoothly curls through the cochlea, and takes the shape that we want it to have. CLIFF MEGERIAN: OK. So what we're doing right now is as you can see, we've put it in our extra temporal lead. We've been able to slide it nicely deep to the temporalis muscle, which is here. And we have a very nice view here of or mastoid. But more importantly, we're gonna be looking straight in here at our round window, and out opening of the round window. There's always a little bit of blood after. That you want to get out of the way. But you can see very nicely-- and I don't like to suck too hard over the round window opening, or so-called cochleostomy. But you want to get the blood out of the way. And you can see our opening there, OK. And our job next is to go ahead and fit our implant, and kind of guide it through that opening. So what I like about this particular implant device is that it has a very simple implant system where in essence you grab gently the electrode lead, like this. And you guide it. So let's take a 20 suction. We could use that. Now some surgeons like to go ahead and put the implant in first, like I do, in terms of the housing and the receiver. But other surgeons like to go ahead and put the leads in first. I like to do it this way. I think it's fairly straight forward. GAIL MURRAY: That side view was perfect. It really showed the stylette well. CLIFF MEGERIAN: May have to re-grab this just a little bit. GAIL MURRAY: Here we go. You see the little end is the stylette that we were referring to before. CLIFF MEGERIAN: Now you want to advance. If you see that white line, there's a white line that goes right up to the cochleostomy site. That white line right there. And we're going to be doing what's called the off-stylette technique. We're gonna go up in power so you can see exactly what we're doing. The nice thing about this off-stylette technique is you can see that there is a stylette right here, this metal stylette. That's keeping it straight and stiff. As I advanced it into the cochleostomy, up to that white line, it is essentially just about to turn at the basilar turn. But if you continue in that direction with that stiff stylette in, you're going to start tearing membranes and tissue in the cochlea. We want to do this in as atraumatically as possible. We want to preserve residual tissue. So what we want to do is we want to pull the stylette out as we're advancing in. And the key is to have this white line right at the cochleostomy site. So you grab the stylette. And you engage, and you push as you're pulling. And I like to get the three ribs in. And there you have it. And you have a nice insertion with the off-stylette technique. And what Doctor Murray is going to be able to show you is some fluoroscopic images of exactly what it's like for that electrode to be traveling within the cochlea. I'm going to give you a closer view. Let's take a suction and a pick. The other thing I really like about this particular device and the way that we do the implant surgery here, is that as you can see, when you have the outer three ribs at the cochleostomy site, it essentially is self-sealing. Now we will put a little tissue around that to seal it again. But it is self sealing. That silastic comes right to the edges of your cochleostomy. It really is a nice system. Why is that important? It's important because you don't want to have a lot of flow-- take a scissors, please-- you don't have a lot of flow of perilymph, or fluid, in and out of the opening that you created, because you could theoretically injure or cause some sort of toxicity to the cochlea. You know, there is these discussions about meningitis and infections. There is evidence at least that the large cochleostomy can potentially be a. Problem So we like to make as smalll a cochleostomy as possible. It also helps preserve residual cochlear function. We'll take a 20 suction. I've taken a little bit of fat here. And we're going to go ahead and seal around that cochleostomy. GAIL MURRAY: So you use the patient's own tissue to seal off the opening of the cochleostomy. OK. CLIFF MEGERIAN: OK. What we're doing now is we're curling the electrode leads within the mastoid. And you can see there's a lot of extra room of that lead to, if necessary, expand as there is growth. We're going to go back to lower power. And we're going to begin closing. We're essentially done with the meat and potatoes part of this cochlear implant. Because just under an hour, we're gonna go ahead and take some gel foam. And this is another thing I like to do. I like to put a little bit of gel foam, which is an absorbable gelatin, and I like to kind of seat it over the mastoid defect. Just like that. And we will go ahead and start closing. OK. So what I like to do-- and this is another important thing I feel is necessary-- is to make sure that we have a layer of periosteum that is covering the device, so that when we close the skin, it's not such that the device is directly under the skin layer. That there is another layer of periosteum. So we pull this back, and we get our edges of our periostomy. This is going to be a very nice closure. And I like to do this as a running stitch. I'm able to kind of collect all of my issue within this stitch. This is a 4-0 Maxon. It is absorbable. So the implant is in now. And one of the things that I like to see at the end of the case is that when you close the periosteum, you really can't see the implant. You can't see the mastoidectomy. There is a nice layer of periosteum closing. At the end of the case-- and I'm sure that this is something that most surgeons try to do-- is that the periosteum is completely covering, number 1-- the implant, which is up here. And you can see the implant is deep to the skin. So we're able to recess our implant and put the device in through this fairly small incision. But number 2-- we have the periosteum completely closed. So this is an extra layer of protection. And we can go ahead and put in our stitches now in the skin. And we use what's called a running subcutaneous, subcuticular stitch. But the other thing that we're able to do now is we try to go ahead during these cases and do intraoperative measurement of the device itself, and make sure that the impedances of the electrodes are working well. And in addition, especially in children, it's nice to know at what stimulation level we're going to go ahead and start the stimulation. So we like to do what's called neural response telemetry. So we go ahead and attach and do a measurement as I'm closing. And it usually doesn't cause us to waste too much time, or take too much time, is a better way of saying it. So whenever we're ready, we can go ahead and do that. And I can go ahead and get the suture going. We have the sutures removed post-operatively. This is an absorbable Maxon suture. And you can see, and we'll bring the edges together very nicely. And we're able to do this, as Dr. Murray is doing her neural response telemetry. We finish up with a little Steri-Strips behind the ear. And these come off usually at seven to 10 days, We put a mastoid dressing on. The patient goes home this morning. It is a really good feeling right now to be finished with your surgery, and to have stimulated the cochlea, and know that the device that you put in not only is in the right position, but also that actually the child or the adult is going to hear, because we've been able to actually directly measure the cochlear nerve potentials, which I think is really important.