This is also called eardrum repair, refers to surgery performed to reconstruct a perforated tympanic membrane (eardrum) or the small bones of the middle ear. Eardrum perforation may result from chronic infection or, less commonly, from trauma to the eardrum.
The tympanic membrane of the ear is a three-layer structure. The outer and inner layers consist of epithelium cells. Perforations occur as a result of defects in the middle layer, which contains elastic collagen fibers. Small perforations usually heal spontaneously. However, if the defect is relatively large, or if there is a poor blood supply or an infection during the healing process, spontaneous repair may be hindered. Eardrums may also be perforated as a result of trauma, such as an object in the ear, a slap on the ear, or an explosion. The purpose of tympanoplasty is to repair the perforated eardrum, and sometimes the middle ear bones (ossicles) that consist of the incus, malleus, and stapes. Tympanic membrane grafting may be required. If needed, grafts are usually taken from a vein or fascia (muscle sheath) tissue on the lobe of the ear. Synthetic materials may be used if patients have had previous surgeries and have limited graft availability.
There are five basic types of tympanoplasty procedures:
- Type I tympanoplasty is called myringoplasty, and only involves the restoration of the perforated eardrum by grafting
- Type II tympanoplasty is used for tympanic membrane perforations with erosion of the malleus. It involves grafting onto the incus or the remains of the malleus
- Type III tympanoplasty is indicated for destruction of two ossicles, with the stapes still intact and mobile. It involves placing a graft onto the stapes, and providing protection for the assembly
- Type IV tympanoplasty is used for ossicular destruction, which includes all or part of the stapes arch. It involves placing a graft onto or around a mobile stapes footplate
- Type V tympanoplasty is used when the footplate of the stapes is fixed
The examining physician performs a complete physical with diagnostic testing of the ear, which includes an audiogram and history of the hearing loss, as well as any vertigo or facial weakness. A microscopic exam is also performed. Otoscopy is used to assess the mobility of the tympanic membrane and the malleus. A fistula test can be performed if there is a history of dizziness or a marginal perforation of the eardrum. Preparation for surgery depends upon the type of tympanoplasty. For all procedures, however; blood and urine studies, and hearing tests are conducted prior to surgery.
Generally, the patient can return home within two to three hours. Antibiotics are given, along with a mild pain reliever. After 10 days, the packing is removed and the ear is evaluated to see if the graft was successful. Water is kept away from the ear, and nose blowing is discouraged. If there are allegies or a cold, antibiotics and a decongestant are usually prescribed. Most patients can return to work after five or six days, or two to three weeks if they perform heavy physical labor. After three weeks, all packing is completely removed under the operating microscope. It is then determined whether or not the graft has fully taken.
Post-operative care is also designed to keep the patient comfortable. Infection is generally prevented by soaking the ear canal with antibiotics. To heal, the graft must be kept free from infection, and must not experience shearing forces or excessive tension. Activities that change the tympanic pressure are forbidden, such as sneezing with the mouth shut, using a straw to drink, or heavy nose blowing. A complete hearing test is performed four to six weeks after the operation.
Possible complications include failure of the graft to heal, causing recurrent eardrum perforation; narrowing (stenosis) of the ear canal; scarring or adhesions in the middle ear; perilymph fistula and hearing loss; erosion or extrusion of the prosthesis; dislocation of the prosthesis; and facial nerve injury. Other problems such as recurrence of cholesteatoma, may or may not result from the surgery. Tinnitus (noises in the ear), particularly echo-type noises, may be present as a result of the perforation itself. Usually, with improvement in hearing and closure of the eardrum, the tinnitus resolves. In some cases, however, it may worsen after the operation. It is rare for the tinnitus to be permanent after surgery.