Grommet

Illustration of a Grommet showing 1.5mm in height

A grommet (Tympanostomy tube)
Image by Mccbala (CC-BY-SA-3.0)

A grommets is a very small plastic ventilation tube about 2mm wide. The grommet is inserted in the eardrum with one flange on the outside and one on the inside of the drum.

Grommets may be known as a tympanostomy tube, ventilation tube, drainage tube, Shepard’s tube, Collar button tube… etc. The names are more often descriptive of the tubes.

The ear is one of the most complex organs, and is made from a diversity of materials found nowhere else in the body. Tiny finely balanced bones interact with super sensory nerve hairs and amazingly tough sheets of cartilage, but all on a microscopic scale.

The ear is composed of three main parts. Interference with any of these three areas can cause deafness.

The outer ear is the ear canal that leads into the eardrum. Beyond the solid sheet of tissue, which forms the eardrum, is the middle ear. This contains three tiny bones which magnify and transmit the vibrations of the eardrum that are caused by a noise, across the cavity of the middle ear to a similar but much smaller membrane. This smaller membrane separates the middle ear from the inner ear. The inner ear is the third part of the ear structure, and contains a fine spiral shaped canal that gives us our ability to hear.

Except for the three tiny bones it contains, the middle ear is normally empty. To keep this space ventilated, a fine tube runs through the skull from the middle ear to the back of the nose. This is the Eustachian tube. When you drive up a steep hill, you swallow and your ears “pop”. This is caused by air rushing through the Eustachian tubes to equalise the pressure inside and outside the ear. When a person has a cold, hay fever or other causes of excess phlegm and mucus production in the nose, the Eustachian tube may become blocked, and unable to function.

In some people, particularly children who have narrower Eustachian tubes, the middle ear may become full of a mixture of phlegm and mucus known as “glue”. The glue material is too thick to pass easily back down the Eustachian tube to the nose, and if it remains in the middle ear, it may cause serious long-term problems.

Grommet in earA glue ear can be effectively treated by inserting a grommet. Under a general anaesthetic, the surgeon puts a small hole in the eardrum (a myringotomy), sucks out most of the glue and inserts a grommet into the hole in the eardrum. This grommet does not drain any further secretions from the middle ear but allows air to enter the ear so that there is no air pressure difference to push further rubbish up from the nose and into the ear.

After three to six months, the grommet falls out and the eardrum usually heals up perfectly afterwards. It is then hoped that no further attacks of glue ear occur. These can be prevented by careful treatment of all colds and nasal infections.

The use of the simple grommet, which is only 3 mm or so long, has prevented a great deal of deafness in children and may prevent more serious complications such as an abscess in the ear or brain.

(Last modified: 13th Oct 2014)

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