Retraction pocket of the ear drum
What is a retraction pocket of the ear drum?
A retraction pocket is a part of the ear drum that has collapsed or become sucked inwards due to a negative pressure within the middle ear.
What causes it?
The cause is complex, but it is thought to be mainly caused by a dysfunctional Eustachian tube. In health, the Eustachian tube (the tube that connects your nose to your ear; you use it to pop your ears) acts to ventilate the middle ear space and equalise pressure within it with the outside world. When the tube is dysfunctional, equalisation cannot occur and a vacuum builds up within the middle ear. This vacuum causes part or all of the ear drum to become sucked inwards, forming a retracted pocket. Retraction pockets start of small but can continue to get larger as more of the ear drum collapses. Others form and then remain stable without an increase in size for many years. Read more about Eustachian tube dysfunction here.
What problems can a retraction pocket cause?
This depends on the severity of the retraction. In mild retractions (shallow pockets), there is usually no problem and they are often only picked up on routine examination of the ears. Severe retractions (large, deep pockets) are at risk of accumulating dead skin from the ear canal. This dead skin should naturally shed and move outwards where it mixes with oils and sweat to form wax. In the presence of a retraction pocket, this dead skin can become trapped within a retraction pocket. The collected dead skin forms a cyst which is known as a cholesteatoma. A cholesteatoma can become infected and cause recurrent or chronic ear infections, and as it continues to collect more dead skin, it grows and starts to erode the middle ear structures causing drainage, hearing loss and other potentially serious complications. Read more about cholesteatoma here.
Even without the development of a cholesteatoma, large retraction pockets can themselves cause recurrent infections and erosion of the hearing bones (ossicles). ENT surgeons generally see retraction pockets as the early stages of a possible cholesteatoma formation.
How is a retraction pocket diagnosed?
Most people with a retraction pocket of the ear drum go to their doctor because of problems with infections, drainage from the ear or hearing loss. An ENT specialist usually makes the formal diagnosis on examination of the ear drum using an otoscope or under the microscope. A hearing test will usually be performed at the ENT clinic assess hearing. A CT scan of the ear may also be organised based on the size of the retraction pocket and the symptoms it is causing.
How is a retraction pocket managed?
Management depends on the following factors:
The severity and size of the retraction pocket
The stability of the retraction pocket
The symptoms the retraction pocket is causing
The presence of a cholesteatoma (collection of dead skin) within the retraction pocket
In retraction pockets that are relatively small and causing no problems, a watch and wait policy can be undertaken with yearly follow up in the ENT clinic. In general, retraction pockets that are stable for at least 5 years with no changes in size or collection of dead skin are unlikely to go on to cause problems and these ears can be left alone and the patient discharged.
If a retraction pocket is very large, unstable (continually getting bigger), is starting to collect dead skin and/or is causing infections and hearing loss, then an operation to repair the retraction pocket is recommended.
With respect to the dysfunctional Eustachian tube, there are currently no effective ways to treat this, but active research is underway. Regular popping of the ears by pinching the nose and blowing out (called a Valsalva manoeuvre) can help force air into the middle ear and help to ventilate it naturally.
What operation is performed for retraction pockets of the ear drum?
Some surgeons will opt to try to ventilate the middle ear with the insertion of a ventilation tube (grommet or T-tube). This may help in some cases of mild or small retractions, but has not been shown to be useful in larger or problematic retractions.
The definitive surgery used to repair retraction pockets of the ear drum is called a cartilage tympanoplasty, in which a piece of cartilage is taken from around the ear and used to reinforce the ear drum to prevent it from retracting in the future. At the same time, the ossicles are usually assessed to make sure that they are working normally. If they are not, then they can often be repaired with a procedure called an ossiculoplasty that can be done at the same time.
Mr Trinidade can discuss in further detail with you the best management options for your retraction pocket.
For more information on cartilage tympanoplasty, click here.
For more information on ossiculoplasty, click here.
This ear drum has small, relatively shallow retraction pockets, one in the front half and one in the back half.
A picture of a normal ear drum with no retraction pockets
The top part of the ear drum is severely retracted and has started collecting dead skin. This collection is known as a cholesteatoma and can cause ear drainage, infections and hearing loss as well as other poentially serious conditions.