Tympanoplasty, 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.
In the United States, ear disorders leading to hearing loss affect all ages. Over 60% of the population with hearing loss is under the age of 65, although nearly 25% of those above age 65 have a hearing loss that is considered significant. Causes include: birth defect (4.4%), ear infection (12.2%), ear injury (4.9%), damage due to excessive noise levels (33.7%), advanced age (28%), and other problems (16.8%).
There are five basic types of tympanoplasty procedures:
Depending on its type, tympanoplasty can be performed under local or general anesthesia. In small perforations of the eardrum, Type I tympanoplasty can be easily performed under local anesthesia with intravenous sedation. An incision is made into the ear canal and the remaining eardrum is elevated away from the bony ear canal, and lifted forward. The surgeon uses an operating microscope to enlarge the view of the ear structures. If the perforation is very large or the hole is far forward and away from the view of the surgeon, it may be necessary to perform an incision behind the ear. This elevates the entire outer ear forward, providing access to the perforation. Once the hole is fully exposed, the perforated remnant is rotated forward, and the bones of hearing are inspected. If scar tissue is present, it is removed either with micro hooks or laser.
Tissue is then taken either from the back of the ear, the tragus (small cartilaginous lobe of skin in front the ear), or from a vein. The tissues are thinned and dried. An absorbable gelatin sponge is placed under the eardrum to support the graft. The graft is then inserted underneath the remaining eardrum remnant, which is folded back onto the perforation to provide closure. Very thin sheeting is usually placed against the top of the graft to prevent it from sliding out of the ear when the patient sneezes.
If it was opened from behind, the ear is then stitched together. Usually, the stitches are buried in the skin and do not have to be removed later. A sterile patch is placed on the outside of the ear canal and the patient returns to the recovery room .
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.
Tympanoplasty is successful in over 90% of cases. In most cases, the operation relieves pain and infection symptoms completely. Hearing loss is minor.
There can be imbalance and dizziness immediately after this procedure. Dizziness, however, is uncommon in tympanoplasties that only involve the eardrum. Besides failure of the graft, there may be further hearing loss due to unexplained factors during the healing process. This occurs in less than 5% of patients. A total hearing loss from tympanoplasty surgery is rare, occurring in less than 1% of operations. Mild postoperative dizziness and imbalance can persist for about a week after surgery. If the ear becomes infected after surgery, the risk of dizziness increases. Generally, imbalance and dizziness completely disappears after a week or two.
Myringoplasty is another operative procedure used in the reconstruction of a perforation of the tympanic membrane. It is performed when the middle ear space, its mucosa, and the ossicular chain are free of active infection. Unlike tympanoplasty, there is no direct inspection of the middle ear during this procedure.
See also Mastoidectomy .
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Uzun, C., M. Velepic, D. Manestar, D. Bonifacic, and T. Braut. "Cartilage Palisade Tympanoplasty, Diving and Eustachian Tube Function." Otology & Neurotology 24 (March 2003): 350-1.
American Academy of Otolaryngology - Head and Neck Surgery. One Prince Street, Alexandria, VA 22314. (703) 806-4444. http://www.entnet.org .
American Hearing Research Foundation. 55 E. Washington St., Suite 2022, Chicago, IL 60602. (312) 726-9670. http://www.american-hearing.org/
"Perforated Ear Drums." Audiology Net. http://www.voice-center.com/tmperf.html .
Tympanoplasty animation. Otolaryngology Houston: http://www.ghorayeb.com/TympanoplastyPictures.html .
"What is Tympanolasty?" PennHealth. http://www.pennhealth.com/health/hi_files/balance/hi13.html .
Monique Laberge, Ph.D.
Tympanoplasty is usually performed on an outpatient basis by an otolaryngologist, a physician specialized in the diagnosis and treatment of disorders and diseases of the ears, nose, and throat. For most adults, Type I tympanoplasty is performed in the office of the otolaryngologist with topical anesthesia at the tympanic membrane site, and subcutaneous local anesthesia injection at the graft donor site. An overnight stay is recommended if the the tympanoplasty involves ossicular replacement.