The eardrum separates the middle ear from the ear canal. It is a thin structure that vibrates with sound waves. Behind the eardrum is the middle ear, which is an air filled cavity.
Perforation of te eardrum is commonly due to infections or injuries. Injury may be caused by:
- Trauma to the ear that increases pressure in the ear canal
- Seevere head trauma and bone fractures
- Intrusion of sharp objects, such as hairpins, cotton swabs, etc.
- Caustic or hot fluids within the ear canal
- Pressure during underwater diving
- Following insertion of ventilation tubes
Middle ear infections (otitis media) are the most common cause of a perforated eardrum. Acute or chronic infections may result in eardrum rupture. In acute otitis media, fullness, pain, fever, and hearing loss are common. Chronic otitis media causes discharge from the ear canal and hearing loss, but pain and fever are frequently absent.
The severity of hearing loss is usually proportional to the size of the hole in the eardrum; the greater the hole, the greater the hearing loss. The location of the hole may also affect the degree of hearing loss. If the hole in the eardrum is due to a severe trauma or explosion, the hearing loss is severe; if the inner ear is also damaged, the hearing loss is permanent and often accompanied by tinnitus .
Perforated eardrums usually heal spontaneously in a few weeks, sometimes in months. During this healing period, the ear must be protected from water contact and trauma. Permanent perforations of the eardrum must be repaired surgically. The purpose of surgical repair is to prevent water escaping into the middle during showering and swimming, infections of the middle ear, permanent hearing loss and to reduce tinnitus.
When the perforation is fresh and small, a thin medical silicone covering may promote spontaneous healing. The surgical repair of the ear drum is called “myringoplasty”. Many methods can be used for a myringoplasty. The basic principle of repair is to close the eardrum by transplanting a tissue patch. The transplanted tissue usually heals within two to three weeks and integrates with the ear tissues. During this healing period, the ear canal is filled with special meterials to keep the tissue patch steady. Recovery of hearing may take two to three months.
The success of ear canal repair depends on the size and location of the hole in the eardrum. Generally speaking, the chance of a successful repair is about 80%. If unsuccessful, the repair must be repeated.