Word: eardrum
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Dates: during 1970-1979
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...some degree of hearing loss. Many are older people whose deafness is caused by progressive nerve damage, which can often be corrected by artificial hearing aids. But a significant number are younger people whose impairment is triggered by disease or injury to the tympanum and ossicles (see diagram), the eardrum and tiny vibrating bones that transmit sound waves to the inner...
Until recently, surgeons had only one method of correcting damage to the eardrum-repair of the tympanum with tissue usually taken from the fibrous lining of the ear muscle. This operation sometimes thickened the eardrum and thus produced only questionable improvements in hearing efficiency. Now surgeons are perfecting a technique for replacing damaged eardrums and ossicles with healthy donor tissue. The operation offers some new hope for an escape from hearing impairment...
...years, doctors who tried eardrum transplants were hampered by their inability to preserve a donor's tissue until it was needed. One solution to their problem was developed by Dr. Rodney Perkins, of Palo Alto, Calif., who tried the buffered formaldehyde solution that has proved successful in the preservation of heart valves. The formaldehyde not only preserves the eardrum and helps retain its shape, but may even improve its tensile strength as well. As a result, doctors can now obtain healthy eardrums and ossicles from deceased donors and store them in an eardrum bank for up to seven months...
Although harvesting and storing eardrum tissue is no longer difficult, the transplant procedure remains delicate. Surgeons make an incision behind the recipient's ear and cut away any diseased or damaged portions of the hearing organs before replacing them with the donor tissue.,If only the donor's eardrum is used, it is fastened to the patient's ossicles with a nylon sling. If the donor's ossicles are used as well, they are connected to the patient's remaining ear bones so that sound vibrations can be conducted unimpeded to the inner...
...take from one to five hours to implant, do not of themselves restore the patient's hearing. Instead, they serve as a scaffolding over which the patient's own ear-canal skin grows to form new ear tissue. The operation does, however, substantially reduce hearing loss. Most eardrum-damaged patients have moderately severe impediments. In most cases, the implants have improved their hearing to within the normal range...