Tympanostomy tube : its medical uses and mechanism of action
Tympanostomy tube, also known as a grommet or myringotomy tube, is a small tube inserted into the eardrum in order to keep the middle ear aerated for a prolonged period of time, and to prevent the accumulation of fluid in the middle ear. The operation to insert the tube involves a myringotomy and is performed under local or general anesthesia. The tube itself is made in a variety of designs. The most commonly used type is shaped like a grommet. When it is necessary to keep the middle ear ventilated for a very long period, a "T"-shaped tube may be used, as these "T-tubes" can stay in place for 2–4 years. Materials used to construct the tube are most often plastics such as silicone or Teflon. Stainless steel tubes exist, but are no longer in frequent use.
MECHANISM OF ACTION
Grommets work by improving drainage in the ear and allow air to circulate in the ear. Grommet placement has been shown to improve hearing in children with glue ear and may lead to fewer middle ear infections in children who have regular episodes of acute otitis media. Grommets can be used to apply antibiotics drops in children with persistent middle ear infections.
Inserting grommets is a common surgical procedure for treating children around the world.Grommets are most commonly used to help improve hearing for children who have a condition commonly called "glue ear" (persistent otitis media with effusion) in both ears, and for preventing ear infections in children who have frequent middle ear infections. Grommets are temporary and often fall out after 12–14 months as the ear heals.Guidelines state that tubes are an option in:
- Recurrent acute otitis media: three ear infections in six months or four infections in a year.The evidence for this recommendation; however, is weak.
- Chronic otitis media with persistent effusion for six months (one ear) or three months (both ears).
- Persistent eustachian tube dysfunction
- Barotrauma: Especially for prevention of recurrent episodes (e.g., after air travel, hyperbaric chamber treatment).
- Grommets should not be inserted in children who have only one episode of otitis media with effusion (OME) that lasts less than 3 months.