Tympanostomy tubes are most beneficial for children in whom middle ear fluid is not cleared up between recurrent AOMs.
Insertion of tympanostomy tube cures the hearing loss caused by middle ear fluid.
Tympanostomy tubes may reduce the incidence of AOMs, relieve symptoms of inflammation and make it easier to diagnose infections.
The most common problems associated with tympanostomy tubes are otorrhoea, a blocked tube and persistent tympanic membrane perforation.
During and AOM, an ear with a tympanostomy tube will leak fluid (otorrhoea). In such a case, the primary treatment is ear drops.
If an open tube does not leak fluid, there is no middle ear infection, even if the tympanic membrane would look abnormal.
In general
A tympanostomy tube is usually constructed from silicone or titanium. The tube is typically inserted in the anterior inferior quadrant of the tympanic membrane, at the site of the light reflex.
The mean time tympanostomy tubes remain functioning is from 6 to 18 months and they are removed spontaneously.
Of children with a tympanostomy tube in situ, even more than half will have one or more episodes of AOM (tympanostomy tube otorrhoea) at some stage.
Indications
The insertion of tympanostomy tubes should be considered if
AOM has reliably been diagnosed 3 or more times in 6 months or 4 or more times in a year
The decision to proceed with surgery is always made individually.
Insertion of tympanostomy tubes is more sensible during the fall and winter, when infections are more common, than in the spring when the exposure to infections is low during the subsequent months.
The need for the insertion of the tubes is also affected by the child's predicted exposure to infections within daycare in the near future (the susceptibility becomes considerably lower from 2 years of age onwards) as well as by uni- vs. bilaterality of the effusion (unilateral effusion can be monitored for longer).
In AOM, tympanostomy tubes enable sampling for bacterial culture because the discharge runs out into the outer ear canal.
Risks
The most common problems associated with tympanostomy tubes are otorrhoea, a blocked tube and permanent tympanic membrane perforation.
Water and bacteria may enter the middle ear via the tube. However, protecting ears against water whilst swimming does not reduce the incidence of infections Swimming with Tympanostomy Tubes.
In some patients, atrophy or scarring may develop on the tympanic membrane (tympanosclerosis, a white plaque present on the tympanic membrane); rarely causes functional impairment.
The tube may leave a persistent hole that requires surgical closing.
The tube may cause granulation tissue or polyp formation on the tympanic membrane (see below tympanostomy tube otorrhoea).
Follow-up
The doctor carrying out the procedure is responsible for the follow-up instructions.
The patency of the tube should be checked at the first follow-up appointment.
The typical interval between subsequent appointments is 4-6 months, until the tube no longer remains in place.
Tympanometry is a good tool for examining an ear with a tympanostomy tube in place Tympanometry.
The removal of a tube by a specialist should be considered if it is still in place 2 years after insertion (an increased risk of persistent tympanic membrane perforation).
Tympanostomy tube otorrhoea
The most common cause of purulent discharge is AOM which develops during an upper respiratory tract infection.
The risk factors for an acute middle ear infection associated with tympanostomy tubes are the same as those for any other AOM Otitis Media in Children: Risk Factors and Pathogenesis; the causative bacteria are likewise the same (Streptococcus pneumoniae, Haemophilus influenzae and Moraxella catarrhalis as well as Streptococcus pyogenes). Particularly in older children, the proportion of infections caused by Pseudomonas aeruginosa and Staphylococcus aureus increases.
Instillation of ear drops: with the child placed in the lateral position the earlobe should be gently pulled backward in order to straighten the ear canal. Pushing on the tragus (i.e. applying tragal pressure) after the drops have been administered will aid deeper penetration. An adequate amount of drops should be administered so that some reach all the way to the middle ear.
After the otorrhoea has resolved the ear should be checked after about one week (is the tube blocked?)
When is specialist intervention indicated?
Otorrhoea persists for more than one week despite antibiotic treatment based on susceptibility testing
In every case of prolonged otorrhoea (over 3 weeks)
The tube irritates the tympanic membrane and leads to the formation of granulation tissue (in addition to discharge, inflammatory tissue is seen on the tympanic membrane). Ciprofloxacin + fluocinolone acetonide ear drops should already be prescribed in primary care.
A suspicion of a complication (e.g. mastoiditis, facial paralysis, brain abscess)
Repeated episodes of AOM (recurrent tympanostomy tube otorrhoea)
Whenever considered appropriate in children with pre-existing hearing impairment or other similar underlying condition
Tympanostomy tube obstruction
Eardrops may be used (e.g. chloramphenicoleye drops: the ear canal is filled by drops, i.e. by approximately one single-use dropper twice daily for one week) to try to dissolve the obstruction, or the obstruction can be mechanically removed by an ear specialist.
Early obstruction, within 1 month of the insertion
An attempt to dissolve the obstruction with ear drops followed by a referral to specialist care
Late obstruction, more than 1 month after the insertion
An attempt to dissolve the obstruction with ear drops followed by a watchful wait. If no effusion develops within the middle ear and episodes of AOM do not recur, the obstruction needs no further intervention.
References
Carbonell R, Ruíz-García V. Ventilation tubes after surgery for otitis media with effusion or acute otitis media and swimming. Systematic review and meta-analysis. Int J Pediatr Otorhinolaryngol 2002;66(3):281-9. [PubMed]
Ruohola A, Meurman O, Nikkari S et al. Microbiology of acute otitis media in children with tympanostomy tubes: prevalences of bacteria and viruses. Clin Infect Dis 2006;43(11):1417-22. [PubMed]
van Dongen TM, van der Heijden GJ, Venekamp RP et al. A trial of treatment for acute otorrhea in children with tympanostomy tubes. N Engl J Med 2014;370(8):723-33. [PubMed]