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Timothy C. Hain,
MD
Last edited:
February 6, 2010
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| Figure 1. Tympanostomy tube (T-tube) -- the small blue piece -- being placed in a retracted ear drum (anterior superior is best location -- see below). | Figure 2. Typical otomicroscope used to place tubes into ear drum. |
Tympanostomy tubes, or "tubes, are a method of creating a perforation in the tympanic membrane (ear drum).
Although the technique of myringotomy (putting a hole in the ear drum to improve hearing) dates back to the 1700's, placing a tube in the ear drum (figure 1) to ventilate the middle ear space began in 1954. This may be due to the general availability of otomiscrosopes (figure 2) which allow physicians to see the ear drum under high magnification while working. Tympanostomy tube insertion is now one of the most frequently performed procedures in otolaryngology.
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| From http://3skimo.com/network_medical/ent_ventilation_tubes.html |
There are presently a large number of variant tubes (see above). Most are commercial products but some doctors manufacture their own out of plastic tubing. The tubes mainly vary in size and tenacity with which they remain in the ear drum. Myringotomies usually close in a few weeks but tubes may remain in place for months to as long as one-two years..
The main purpose of ventilation tubes is to ventilate the middle ear, usually in an attempt to control an infection or drain fluid. Tubes may also be inserted to deliver pressure (the Menniett device for Meniere's disease), medication, relieve pain, administer medications, or simply to substitute for a faulty eustachian tube.
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| Ideal location of tube (from Paparella, 2009) |
When a myringotomy is performed, the ear is washed, anesthesia is applied, a small incision made in the eardrum, the fluid sucked out, a tube inserted, and the ear packed with cotton to control bleeding. If local anesthesia is used, a cream containing lidocaine and prilocaine is applied to the ear canal about 30 minutes before the myringotomy (e.g. EMLA cream). Other methods can be used for anesthesia too.
According to Paparella (2009), tubes should ideally be inserted into the anterior superior quadrant, adjacent to the malleus, and halfway between the umbo and short process of the malleus.
A tube should not be inserted into the posterior superior quadrant because of important middle ear structures located in that region (i.e. ossicles). Likewise, placement into the posterior inferior quadrant could potentially damage the round window or potentially be complicated by a dehiscent jugular bulb.
There are many variants of tubes -- the choice of which depends on clinical judgement.
Tubes often fall out (extrude), with this happening more quickly for smaller tubes than larger ones. Tubes with lumens (openings) of about 1.1 mm will last about a year before spontaneously extruding. Tubes of 1.5 mm size typically stay in place for years. Tubes intended to remain for long periods of time often have flanges or are arranged in a "T" so that they are less likely to come out (extrude). Another design is called a "grommet".
Complications, such as otorrhea, tympanosclerosis, and cholesteatoma, have been reported in the literature after its application. In a study by Kalcioglu and others (2003), otorrhea developed in 3 (0.8%) cases. Tympanosclerosis was seen in 74 (20.2%) cases. Tympanic membrane perforation, retraction pocket, granulation tissue, and atelectasis were seen in 4.6%, 5.2%, 1.1%, and 6%, respectively. Hearing results were improved postoperatively in 93.4% of patients (median, 14.2 dB) and worse in 6.6% of patients (median, 8.3 dB). The average extrusion time was 7.3 months for grommet and 16.3 months for T-tubes.
Tubes may become blocked. This can usually be determined by the patient in that when they blow their nose, no air escapes through the tube and this alerts them that the tube may be blocked. In the author's practice, these situations are handled by cleaning the ear using a microscope, and sometimes by providing the patient with a thin antibiotic ear drop.
There is some physician and patient concern about allowing water such as might be introduced during bathing or swimming into an ear with a tube. Several large meta-analysis type studies have shown no increase in ear drainage in patients who are exposed to water (Lee et al, 1999; Carbonell et al, 2002).
The ear tube may move inward and get trapped in the middle ear, rather than move out into the external ear, where it either falls out on its own or can be retrieved by a doctor. The exact incidence of tubes moving inward is not known. It probably is rare in as much as tube insertion is very common. In theory, it could increase the risk of further middle-ear inflammation, formation of a mass in the middle ear, or infection due to the presence of a foreign body. It would also seem likely that the tube would naturally migrate out of the middle ear into the eustachian tube and into the throat.
Tubes are not at all a contraindication to flying. In fact, flying with a tube is safer in some ways as it provides a pressure relief for the ear drum.
Tubes as well as any procedure that involves making a hole (perforation) in the ear drum such as injections of drugs, make it impossible to perform certain diagnostic ear tests. These include:
Because of these considerations, one should schedule ones tubes or other procedures AFTER diagnostic testing is complete.
Tympanostomy tubes in children are generally felt indicated in recurrent otitis media, failed multiple courses of antibodies, and persistent otitis media with effusion. Other indications are persistent retraction with discomfort, erosion of the ossicles, manifest or impending complications such as facial paralysis, labyrinthitis, or mastoiditis. Delay in initiation of speech, allergy, seasonality are all variables to consider.
Allergy treatments and decongestants generally are not helpful in treating persistent otitis media with effusion. Antimicrobials and steroids may work but lack long-term efficacy.
In the posterior-superior quadrant of the ear drum, look to see if the eardrum touches the incus. If it does, this is a risk of erosion and development of a conductive hearing loss in childhood.
| © Copyright April 14, 2010 , Timothy C. Hain, M.D. All rights reserved. Last saved on April 14, 2010 |