Ventilation tubes (Grommets) are prosthetic tubes inserted into the middle ear cavity via a perforation in the ear drum. These tubes serve to ventilate and drain the middle ear cavity.
Ventilation tubes can be of different materials like teflon, silicone, titanium, gold etc. These materials may be coated with silver oxide.
Features of ventilation tube:
1. It should not be irritating to the middle ear
2. It should not elicit foreign body reaction
3. It should be sterilizable
4. It should not cause allergic reaction in the individual
Ventilation tubes are of two types:
1. Grommet (dumbbell shaped): Used for short term purposes. Gets extruded within 6 months.
2. T tube (T shaped): Used for long term purposes. Stays for at least 1 - 2 years.
The general rule of thumb is that the larger and stiffer the flange that goes into the middle ear, the longer it stays in situ. The longer it stays, the longer gets its potential benefits. T tube is one such tube that stays for a longer period of time without extrusion. The longer the tube stays in position, greater are the chances of complications. These complications include infection,granulation tissue formation, permanent perforation of ear drum, thinning of ear drum with possibility of retraction pockets.
Indications for ventilation tube insertion:
1. Secretory otitis media
2. Adhesive otitis media
Site of insertion: It is ideally inserted in the antero - inferior quadrant of the ear drum through a radial incision. This site is chosen due to the proximity of the eustachean tube, and to maximize the duration of tube function.