Myringotomy and ear tubes

Definition

Myringotomy is a surgical procedure in which a small incision is made in the eardrum (the tympanic membrane), usually in both ears. The word comes from myringa, modern Latin for drum membrane, and tome, Greek for cutting. It is also called myringocentesis, tympanotomy, tympanostomy, or paracentesis of the tympanic membrane. Fluid in the middle ear can be sucked out through the incision.

Ear tubes, or tympanostomy tubes, are small tubes, open at both ends, that are inserted into the incisions in the eardrums during myringotomy. They come in various shapes and sizes and are made of plastic, metal, or both. They are left in place until they fall out by themselves or until they are removed by a doctor.

Purpose

Myringotomy with the insertion of ear tubes is an optional treatment for inflammation of the middle ear with fluid collection (effusion), also called glue ear, that lasts more than three months (chronic otitis media with effusion) and does not respond to drug treatment. It is the recommended treatment if the condition lasts four to six months. Effusion is the collection of fluid that escapes from blood vessels or the lymphatic system. In this case, the fluid collects in the middle ear.

Initially, acute inflammation of the middle ear with effusion is treated with one or two courses of antibiotics. Antihistamines and decongestants have been used, but they have not been proven effective unless there is also hay fever or some other allergic inflammation that contributes to the problem. Myringotomy with or without the insertion of ear tubes is NOT recommended for initial treatment of otherwise healthy children with middle ear inflammation with effusion.

In about 10% of children, the effusion lasts for three months or longer, when the disease is considered chronic. In children with chronic disease, systemic steroids may help, but the evidence is not clear, and there are risks.

When medical treatment doesn't stop the effusion after three months in a child who is one to three years old, is otherwise healthy, and has hearing loss in both ears, myringotomy with insertion of ear tubes becomes an option. If the effusion lasts for four to six months, myringotomy with insertion of ear tubes is recommended.

The purpose of myringotomy is to relieve symptoms, to restore hearing, to take a sample of the fluid to examine in the laboratory in order to identify any microorganisms present, or to insert ear tubes.

Ear tubes can be inserted into the incision during myringotomy and left there. The eardrum heals around them, securing them in place. They usually fall out on their own in 6-12 months or are removed by a doctor.

While they are in place, they keep the incision from closing, keeping a channel open between the middle ear and the outer ear. This allows fresh air to reach the middle ear, allowing fluid to drain out, and preventing pressure from building up in the middle ear. The patient's hearing returns to normal immediately and the risk of recurrence diminishes.

Parents often report that children talk better, hear better, are less irritable, sleep better, and behave better after myringotomy with the insertion of ear tubes.

Description

The procedure is usually done in an ambulatory surgical unit under general anesthesia, although some physicians do it in the office with sedation and local anesthesia, especially in older children. The ear is washed, a small incision made in the eardrum, the fluid sucked out, a tube inserted, and the ear packed with cotton to control bleeding.

There has been an effort to design ear tubes that are easier to insert or to remove, and to design tubes that stay in place longer. Therefore, ear tubes come in various shapes and sizes.

Preparation

The child may not have food or water for four to six hours before anesthesia. Antibiotics are usually not needed.

Aftercare

Use of antimicrobial drops is controversial. Water should be kept out of the ear canal until the eardrum is intact. A doctor should be notified if the tubes fall out.

Risks

The risks include:

• Cutting the outer ear

• Formation at the myringotomy site of granular nodes due to inflammation
• Formation of a mass of skin cells and cholesterol in the middle ear that can grow and damage surrounding bone (cholesteatoma)

• Permanent perforation of the eardrum.

The risk of persistent discharge from the ear (otorrhea) is 13%.

If the procedure is repeated, structural changes in the eardrum can occur, such as loss of tone (flaccidity), shrinkage or retraction, or hardening of a spot on the eardrum (typmanosclerosis). The risk of hardening is 51%; its effects on hearing aren't known, but they are probably insignificant.

It is possible that the incision won't heal properly, leaving a permanent hole in the eardrum, which can cause some hearing loss and increases the risk of infection.

It is also possible that the ear tube will 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, but it could increase the risk of further episodes of middle-ear inflammation, inflammation of the eardrum or the part of the skull directly behind the ear, formation of a mass in the middle ear, or infection due to the presence of a foreign body.

The surgery may not be a permanent cure. As many as 30% of children undergoing myringotomy with insertion of ear tubes need to undergo another procedure within five years.

The other risks include those associated with sedatives or general anesthesia.

An additional element of post-operative care is the recommendation by many doctors that the child use ear plugs to keep water out of the ear during bathing or swimming, to reduce the risk of infection and discharge.

Acute otitis media

Inflammation of the middle ear with signs of infection lasting less than three months.

Chronic otitis media

Inflammation of the middle ear with signs of infection lasting three months or longer.

Effusion

The escape of fluid from blood vessels or the lymphatic system and its collection in a cavity, in this case, the middle ear.

Middle ear

The cavity or space between the eardrum and the inner ear. It includes the eardrum, the three little bones (hammer, anvil, and stirrup) that transmit sound to the inner ear, and the eustachian tube, which connects the inner ear to the nasopharynx (the back of the nose).

Tympanic membrane

The eardrum. A thin disc of tissue that separates the outer ear from the middle ear.

Tympanostomy tube

Ear tube. A small tube made of metal or plastic that is inserted during myringotomy to ventilate the middle ear.

For Your Information

Books

• Lim, David J., ed., et al. Recent Advances in Otitis Media: Proceedings of the Sixth International Symposium, June 4-8, 1995, Marriott Harbot Beach, Ft. Lauderdale, Florida. Hamilton, Ontario: B. C. Decker Inc., 1996.

• Wiet, Richard J., Steven A. Harvey, and George P. Bauer. "Management of Complications of Chronic Otitis Media." In Otologic Surgery, ed. Derald E. Brackmann, Clough Shelton, and Moises A. Arriaga. Philadelphia: W. B. Saunders Co., 1994.

• Terris, Mark H., Anthony E. Magit, and Terence M. Davidson. "Otitis media with effusion in infants and children: Primary care concerns addressed from an otolaryngologist's perspective." Postgraduate Medicine 97, no. 1 (Jan. 1995): 137-151.

Source: Gale Encyclopedia of Medicine, Published December, 2002 by the Gale Group

The Essay Author is Mary Zoll PhD.

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