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The Ear it's Construction, Function and a description of ENT medical procedures.

The construction:

Cerumen - Ear Wax

Cerumen – a clear sticky fluid is excreted from the ceruminous glands in the ear canal, when mixed with the dead skin cells, dust and dirt of the ear canal becomes ear wax. Keeping the ear drum lubricated, as well as cleaning the canal it is slightly acidic killing bacteria making a barrier to stop fungal growth and trapping foreign particles from nearing the ear drum by coating the ear canal hairs making them sticky. As well as this; wax is hygroscopic, it absorbs water, swelling when there are moist humid conditions. If too much wax is present however, this property can have the negative effect of blocking off the canal reducing the amount of sound heard, causing a conductive hearing loss which generally is relieved when the wax dries out and shrinks.

The gatherer of sound, the external visible ear is known as the Pinna.

How we hear sound:

Common ear operations:

The insertion of Tympanostomy tubes - Grommets:

Grommets (Ventilation Tubes) The middle ear is connected to the back of the nose by the Eustachian (pronounced you-stay-shun) tube. This tube helps to maintain an equal pressure inside and outside the middle ear, and so allows the eardrum to vibrate efficiently. 

The tube opens to allow the pressure equalize in the middle ear space. This may cause the “click” or “pop” which can experience when swallowing, or when flying. These “pops” are evidence of a working Eustachian tube. 

If the Eustachian tube does not work properly or is “blocked” by inflammation, the air in the middle ear is absorbed but cannot be replaced. This causes the air pressure in the middle ear to be less than the air pressure in the ear canal. The negative pressure (partial vacuum) in the middle ear causes the eardrum to become progressively more in-drawn and eventually the body responds by filling the space with fluid to protect the eardrum and middle ear contents. This is the common condition called “glue ear”. “Glue ear” is very common in children younger than 6 - 7 years of age, due to the shortness of their necks at that age causing constrictions on the tube at its opening, this condition normally dissipates spontaneously in the majority of cases, usually within three months. 

The longer the fluid remains trapped there though, the thicker “egg white like” and more tenacious the secretions become, and spontaneous resolution becomes less likely.Grommets (Ventilation tubes) Grommets are tiny little plastic tubes, which are inserted into the Tympanic Membrane “eardrum”. The grommet does the work that the poorly functioning Eustachian tube should be doing. Therefore ventilating “aerating” the middle ear, reducing secretions, allowing better eardrum vibration “function” and giving the middle ear a chance to recover from infections. In America grommets are simply known as “ventilation tubes”. 

Grommets are used for one of three main reasons: 

1)Persistent middle ear effusions, or fluid trapped behind the eardrum “glue ear”. This may cause considerable hearing loss “deafness”, and sometimes earache and slight imbalance. 2)Recurrent otitis media “middle ear infections”. These are painful recurrent ear infections, which may be accompanied by a high temperature, poor appetite and general lethargy. 

3)The (very unusual) case where the vacuum in the middle ear threatens to damage the eardrum or the contents of the middle ear.

What causes these ear problems? Something about the working of the Eustachian tube is very commonly amiss in children up to about the age of 6 or 7. Sometimes the cause is adenoiditis, with enlargement and infection of the adenoids causing obstruction of the Eustachian tube (a tube like structure that connects the middle ear to the back of the nose/upper throat). Rare causes include sinusitis, cleft palate, immune deficiencies and bottle-feeding. Parental smoking is also a potent cause of both acute and chronic ear problems in young children. 

Grommet insertion surgery.  

This is a quick (10-15 min) procedure usually performed under general anaesthesia. In adults, who are not considered suitable for general anaesthesia, grommet insertion may be performed under local anaesthesia (a special anaesthetic cream in the ear) with little discomfort. 

This is a day case procedure and patients usually go home on the same day. A microscope is used to visualise the tympanic membrane “eardrum”. A tiny slit “cut” is made in the eardrum (myringotomy). Fluid “glue” within ear is drained by suction. A grommet is then inserted through the “hole” made in the eardrum to keep middle ear ventilated and healthy. In a child, if adenoids are enlarged and the child is having the second or third sets of grommets inserted, the surgeon may also remove the adenoids. 

Complications of the grommet surgery 

This is a relatively safe operation, however no surgery is totally free of any risk. 

1) Infection- grommet may cause ear infection and even rarely be significant enough to require the removal of the grommet. However it is usually is to treat with antibiotics. 

2) Persistent eardrum perforation- most grommets fall out of ears spontaneously after an average of 9 months. When they do, most eardrums heal up, by scarring however in about 2% of patients, the eardrum fails to heal or leave a smaller residual perforation “hole”. 

Some of these patients may require a further operation in future to repair the remaining hole, of course only if it causes any problem. You should discuss with your surgeon about possible alternatives to surgery 

Expectations and advice following grommet insertion surgery ·This is usually a day case surgery, but if other procedures need to be carried out as well (e.g. tonsillectomy) an overnight stay may be required in some cases. ·

A follow up appointment will be arranged for about 6 weeks after surgery. 

Avoid getting water into the ears as this may easily cause infection in the ears. This applies to showers, bathing, washing hair as well as swimming. 

Swimming is only permitted after the follow-up appointment has given the all clear. Avoid diving with a grommet in the ear. Earplugs must be used for all these activities. Alternatively, cotton wool heavily smeared with Vaseline is an excellent and sometimes more comfortable alternative. ·

You may get a blood-stained discharge after the surgery for couple of days. ·If ear discharge persists, smells foul or there is increased pain seek help as this suggests infection and treatment with antibiotic ear-drops will be required. ·

Pain is normally fairly minimal and can be controlled with simple painkillers. ·Avoid poking of ear buds, matches, keys or a dirty finger. This can introduce infection. Clean ear with a damp cloth around the outside. ·

Grommets usually fall out of ear in about 9 months. They spontaneously grow out and are ejected by the eardrum and therefore very rarely have to be removed. Usually they fall out of the ear and may be found on the pillow upon awaking. The eardrum usually heals up where the grommet was sited. ·If your grommet falls out early do not panic. You do not need to contact your doctor immediately. You should continue keeping your ear waterproof and attend the outpatient clinic as planned. ·

Sometimes (20%- 25% chance) repeat sets of grommets are needed if the fluid re-accumulates. A hearing test will indicate if this is the case. The older a child gets, the less likely this will be. In a way, grommets “buy time” by maintaining hearing and preventing serious eardrum damage until the child is older when the Eustachian tube function often starts working properly, and fluid does not readily recur. ·Do not drive for 48 hours (because of the effect of the general anaesthetic). ·Flying is allowed.

Myringoplasty / Tympanoplasty 

Myringoplasty is an operation carried out to repair a chronic (non-healing) hole in the eardrum.

A hole in the eardrum may lead to repeated ear infections with pain, discharge and hearing loss. If this is the case, surgery is recommended to close the perforation and put an end to these infections. 

Aims of the surgery 

1) Prevent recurrent ear infections.

2) Improve hearing, if there is a conductive hearing loss due to eardrum perforation.

3) Enable patients to swim or get the ear wet without facing infection as a consequence. 

Myringoplasty surgery 

The operation is performed under general anaesthesia, and it usually takes about 1-2 hours. It involves taking a layer of scalp “fascia” usually behind ear in the hairline to use as a graft. This graft is then slipped behind the drum to cover the perforation.

There are two approaches to the eardrum. One is the approach to the eardrum through the ear canal “end-aural approach”. The second approach is to make an incision “cut” behind the ear and flipping it forward “post-auricular approach”.

This is decided depending on the site and the type of the eardrum perforation, the reason for the surgery and surgeon’s preference.

At the end of the surgery, the ear is packed with special ribbons.

Complications of Myringoplasty 

1) Infection- it could potentially cause graft failure and therefore failure to heal the eardrum.

2) Bleeding- very unlikely, however small blood-stained discharged can be expected within the first couple of days after the surgery.

3) Graft failure- graft success can be as high as 80%. However the success rate varies depending on many factors such as the indication for surgery, the size and the site of perforation, presence of chronic infection and general patient’s health e.g. diabetic.

4) Hearing loss- this is very rare, but potentially with any ear surgery there is small risk of deteriorating the hearing rather than improving it. 

Expectations and Advice following Myringoplasty/ Tympanoplasty surgery 

·You may wake up with a head bandage around your head. If so, this will be removed the following day.

·You can go home the day after the surgery or later the same day.

·There will be some packing inside your ear. Do not remove any pack from your ear. 

·The ear pack must be removed within 2-3 weeks. You should have an outpatient appointment before the end of this period. 

·Do expect sensations of ear blockage and pressure while having the pack in your ear. 

·Do expect mild dizziness/ instability of balance. 

·You may have a small blood-stained discharge “ooze” in the first 24-48 hrs. 

·Do not expect any improvement in hearing before the ear pack is removed or even the first few weeks after packs are removed. 

·There should be no increase in pain, discharge or bleeding. 

·Avoid getting water on the wound or in the ear. 

·Off work/ school for about 10 days. A “sick note” will be provided.

Less common operations:

Mastoidectomy:

Mastoid surgery is performed when an infection in the middle ear cleft spreads to the mastoid cavity. Commonly a pocket of pussy skin (cholesteatoma) develops from the inside surface of the ear drum invading the middle ear and subsequently the mastoid. This may cause recurrent ear discharge. The cholesteatoma may after a while also invade the ossicles (the 3 bones in the middle ear that cross the gap between the ear drum and the cochlea), causing an increased mixed hearing loss. Other important structures like the brain, the nerve that supplies the muscles of the face and blood vessels run close by and hence the cholesteatoma must be removed to prevent these structures from being eroded. The operation to do this is known as a mastoidectomy. Provided that the operation is identified quickly enough there is normally over an 80% chance of success in fully recovering the hearing. 

The operation: 

The operation is usually carried out under a general anaesthetic. Some cholesteatomas which are very small can be removed through the ear canal. Most cholesteatomas require that an incision be made behind or in front of the ear to expose the tumor adequately. The cholesteatoma is completely removed microscopically 

In more extensive cholesteatomas, the disease may have eroded through the bony wall which separates the middle ear from the mastoid. This may require a more radical operation, removing the wall separating the middle ear from the mastoid. The result is a so-called open cavity which requires life-long follow-up in the outpatient clinic, every few months.

In less extensive cholesteatomas, especially when infection is well controlled before surgery, an intact canal wall operation may be the favoured procedure. This operation preserves the wall between the middle ear and mastoid. The principal advantages of the intact canal wall operation are a more normal canal and ear drum, and a greater possibility of hearing restoration. In addition, most patients with the intact canal wall operation can allow water in the ear. The chief disadvantage of the intact canal wall operation is that a regrowth of cholesteatoma may not be evident. Thus, many ear surgeons will delay rebuilding the bones of hearing for a year after an intact canal wall operation for cholesteatoma. The ear drum is opened at the second operation and the bones of hearing are then reconstructed. If a regrowth of cholesteatoma is found, the disease is again removed and reconstruction may be delayed for another 6 months or a year. Repeat CT scans may also be performed in some cases to avoid further surgery.

Even with careful microscopic surgical removal of cholesteatoma, 10% to 20% of cholesteatomas can recur. In children, some ear surgeons report up to 50% recurrence rates with the intact canal wall procedure. Thus, careful follow-up visits must be planned, in order to identify regrowth early on.

After the disease has been removed, a graft will be used to seal up any hole in the eardrum, and packing placed in the ear canal.

There are multiple variations of the mastoid operation, so your surgeon will explain the details which apply to you.

What happens after the operation?

You will stay in hospital at least one night after the operation. If the stitches are not dis-solvable, they will be removed after one or two weeks, either by the hospital or your practice nurse. The packing will be removed from your ear after 1 to 3 weeks.

If you have a mastoid cavity after the operation, it will need regular care in the ear nose and throat outpatients department until it is entirely healed.

What are the risks of the operation?

· The risks of a general anaesthetic.

· The risks of the operation are similar to those of leaving the cholesteatoma in your ear, only more controlled and much rarer. There is a risk of reduced hearing after the operation but this is often able to be improved by an operation at a later date once the cholesteatoma has been controlled.

· There is a rare risk to the facial nerve resulting in a permanent weakness of the side of the face, (facial paralysis).

· Dizziness. Frequently a temporary occurrence. Rarely may be a permanent problem

Sometimes a second operation is planned about one year after the original operation to check for recurrence of the cholesteatoma. There is also a risk of taste disturbance on one side of your tongue.

When can I wash my hair/swim/fly?

If you are careful about keeping water away from your operated ear, you can wash your hair after a week.

You should be able to swim about four to six weeks after the operation, depending on how well the operation has healed, and so you should ask your surgeon at your postoperative outpatients appointment. 

When can I fly?

You should be able to fly at any time after the operation unless you have also had an operation to improve your hearing at the same time as the mastoid operation - again, check with your surgeon
Reference(s) www.ent-info.nhs.uk accreditation to the North West London Hospitals NHS