Cochlear implant assessment service and electric-acoustic simulation

Hello, my name is Harry Powell. I'm one of the cochlear implant surgeons here at Guy's and Thomas' NHS Foundation Trust. I am one of a team of 5 surgeons who may be looking after you or your child.

In these short videos I'm going to explain the cochlear implantation procedure and the risks. This is part of the consent process so that you will understand what the procedure involves prior to agreeing to it.

By now you may have been through the full assessment. This will have involved a number of appointments and also we will have discussed you in our multidisciplinary team meeting. If, as a team, we think that cochlear implantation will be better for you than your conventional hearing aids, then we may be able to offer cochlear implantation as the next stage in your care.

Before surgery

Before surgery it is important that you or your child have a vaccination against meningitis. Because the cochlea is close to the brain, there's a very slightly increased risk of meningitis after the operation. To minimise this risk we therefore ask that you have the vaccination prior to the surgery.

We're going to give you 2 envelopes, one for the GP and one for yourselves so that you have all the information. We ask that you make an appointment with your GP as soon as possible so that you can have the vaccination at least a week before the surgery.

Before the operation a pre-assessment will take place. This is an appointment for us to check your general health prior to the surgery. We may ask you to go for an appointment in the pre-assessment clinic here at St Thomas' after your consultation, or you'll have a separate appointment before the surgery.

All our adult surgery takes place at Guy's and almost all of our children's surgery takes place at the Evelina London Children's Hospital on the St Thomas' site.

You will have a general anaesthetic for your operation. The anaesthetic doctors will look after you and put you off to sleep so that you're completely unaware and you don't feel any pain.

It is important that you fast before the surgery and we give you a letter with instructions as to when to stop eating and drinking.

The operation can take anything from 1 and a half to 3 hours for each side every patient is slightly different and the anatomy varies from case to case. This means that sometimes it is more complex than others. The crucial thing to remember is that we will take the time it needs and carry out the operation in the safest possible way. 

You are looked after during the surgery by the anaesthetic team. This involves having a small tube placed through your mouth and into your windpipe so we can breathe for you while you're asleep.

After surgery

Sometimes after the operation people get a sore throat for a few days. That's because of the breathing tube and it will settle and there's nothing to worry about.

There's a nerve that runs through your ear called the facial nerve. It supplies all of the muscles of the face on that side, the ones that enable you to close your eye, to smile and to raise your eyebrow. 

We monitor this nerve during the operation. To do this we have to put some tiny needles into the face one at the corner of the mouth and one just above the eye. Afterwards when we take these out, this can lead to some bruising and that usually settles over a week or so.

We then prepare the area behind your ear by shaving some of the hair. This is so that we can keep the area as sterile as possible.

If you or your child are having 2 implants, then we try to make sure that they're as symmetrical as possible under the skin. We can't however guarantee rhat they'll be exactly the same on either side.

In small children and babies the skin and soft tissues are very thin so the implant can look quite prominent behind the ear after the surgery. This is nothing to worry about and it will just entirely settle as your child grows.

That is the end of the first video. Now you can watch the next video which explains more about the operation itself and what the procedure involves.

Consent form

This is a consent form. We write on the inside about the risks and the benefits of the surgery and we ask that you sign on the opposite page, so that we can then have a formal agreement to proceed with the operation.

We will go through this in your consultation and you'll have an opportunity to ask any questions that you've thought of, and we'll go through everything again on the day of your surgery.

When everything is ready in theatre, we sterilise the area behind the ear. We make a cut through the skin and the soft tissues. You will have a scar behind the ear but this heals very well and usually after about a year it is barely visible.

Once the bone behind the ear is exposed we go through that bone to access the middle ear in the cochlea, without disturbing the ear canal. To get to the middle ear space we have to go between the facial and the taste nerves.

Risk

There is a small risk of damage to both of these nerves during the operation. The facial nerve supplies all the muscles of the face on that side and hence if ther was damage this would cause weakness of those muscles. This risk is very small but it's important that we warn you about it and this is also why we monitor the nerve during the operation.

If the narrow gap between the facial nerves and the taste nerves is so small that we can't get through, then sometimes the taste nerve is damaged. That damage would result in an abnormal taste sensation on the tongue on the side of the operation towards the front of the tongue. It causes a sort of metallic taste. That will resolve and settle down but it can take 3 to 6 months to do so. Sometimes the nerve is actually bruised and you still get those symptoms but they would settle more quickly.

Access

Accessing the cochlea can be difficult, particularly if there has been recent infection or there's inflammation in the middle ear or scarring. We always try to insert the implant through one of the cochlear's natural openings called the round window, and we will aim to try and preserve any hearing that you still get benefit from. Despite our best efforts we can't guarantee to preserve the hearing, but we will always try.

Cochlear implants are currently guaranteed by their manufacturers for ten years. However just like any electrical device, your television, or your washing machine, there could be a fault or a problem with it before then. That said, we've got plenty of patients who had their first implant more than 20 years ago and they're still getting benefit from it.

As you recover from the surgery, you may find that you feel your balance is affected for a short while. Immediately after the operation you might feel very dizzy and sometimes you can feel a little bit sick. This can either be because of disturbance of the inner ear from inserting the implant, which can affect the balance function, or sometimes it's also related to some of the anesthetic drugs that we give you while you're asleep.

Either way we can give you medicines that help reduce the nausea and the sickness feeling, and they'll generally make you feel a lot better. We can also give you medicines that you can take home if you need them, and usually over a few days this will all settle down and you'll feel back to normal.

Tinnitus

Tinnitus is a noise in the ears that some people experience. It's a noise inside the head rather than a sound that comes from an external source. Some patients already have tinnitus and it may get worse after the surgery.

If you've never had tinnitus before, you may experience it after the operation. Usually it settles over a few days. Sometimes when the implant is switched on, it goes away completely.

We can't predict or guarantee what will happen with the tinnitus, but generally it will subside, and we will be here to help you or advise you if it's bothersome.

Every operation carries a small risk of bleeding. When you wake up from the surgery you will have a head bandage on and this is there to protect that ear and to reduce the chance of bleeding. You may get some bruising that runs down the neck from behind the ear. This is more common in older patients and it usually settles over about two weeks.

Antibiotics

There is a small risk of infection. Due to this we give you antibiotics during the operation whilst you're asleep, through your drip. Sometimes we also give you a couple more doses after the surgery whilst you're still in hospital.

Occasionally we'll give you oral antibiotics to go home with but we'll explain this after the operation and the nurses would also go through it with you before you go home.

That is the end of the second video. Now you can watch the third video which is about what to expect after your operation.

When you wake up from the operation you'll be in a room called the recovery.

If your child is having the surgery, then you'll be invited down, once they're awake enough so that you can see them and look after them yourself. They may be a little bit drowsy or a little bit woozy from the anaesthetic drugs.

You may not remember much about being in the recovery area. Once you're awake enough, we'll transfer you back up to the ward where the nursing team will be ready to look after you. You'll have the bandage on protecting your ear. It usually comes off the following morning, either at home or in hospital, before you're discharged home.

After your operation you might go home the same day or stay one night in hospital. Depending on what time of day your operation finishes will usually determine whether you need to stay overnight afterwards.

The operation site will usually be sore for 7 to 10 days afterwards and we encourage you to take simple painkillers for that time.

Before you're discharged home all of this will be explained to you by the nurses looking after you.

To reduce the chance of infection, one important thing we ask, is that you keep your ear and the wound dry afterwards for a little while. You cannot wash your hair but you can use dry shampoo. Your surgeon will explain how many days they want you to keep the ear dry for.

Depending on your surgeon, you may have some white sticky dressings over the wound to protect it while it heals up. These can stay on until you come back to clinic to see us.

Once you're well enough you'll be allowed to go home. We will make a follow-up appointment for you 7 to 14 days after your surgery.

While you are recovering, if you get any concerns or you have any unexpected symptoms such as worsening pain, fever, or severe dizziness, then please contact the implant administration team and we'll be able to advise you.

Thank you for your attention. We hope that watching these films has helped improve your understanding of the cochlear implant operation.