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COLUMBIA-PRESBYTERIAN MEDICAL CENTER
For immediate release
CONTACT: Ruth Flaherty, 212/305-5587
TITANIUM BONE IMPLANTS USED TO SECURE PROSTHETIC EARS AND HEARING AIDS
NEW YORK, N.Y., MAY 6, 1997 -- Borrowing from the field of dentistry,otolaryngologists are using titanium bone implants to create permanent anchors for prosthetic ears.
This is a major advance for people who are missing an ear because of cancer, trauma, or birth defects, reports Jack Wazen, MD, Associate Professor of Clinical Otolaryngology (Head and Neck Surgery) and Director of Otology at Columbia-Presbyterian Medical Center, one of a handful of physicians in the New York City area currently performing this procedure. The only other solution for these patients is to attach the prosthetic ear to the head with glue, which creates a tenuous bond.
The implants are inserted during a two-to-three-hour outpatient surgical procedure using local anesthesia. First, Dr. Wazen cuts open the scalp to expose a silver-dollar-sized portion of the mastoid bone, which is located just behind the ear canal. Then a hole, 6 mm wide and 3 to 4 mm deep, is drilled into the bone. (If the hole is drilled any deeper, the surgeon risks breaking through the skull to the soft tissue underneath.) The hole is then countersunk, maximizing the amount of surface contact between the bone and the implant, and the implant is screwed into place.
At least two implants, spaced a minimum of 15 mm apart, are affixed to the skull. "We prefer to use three implants, if the anatomy of the bone makes it possible," says Dr. Wazen. "With three, we can create a more stable, tripod-like support for the prosthesis." (An implant for a bone-anchored hearing aid, if needed, can also be inserted during the operation.)
Before the incision is closed, holes are punched in the overlying tissue so that the implants will protrude a few millimeters above the skin, providing attachment points for the prosthesis. Patients can go home a few hours after the procedure and resume normal activities within a day or two.
However, the prosthesis cannot be attached for three to four months, the time it takes for the bone to integrate into the titanium and stabilize the implants, a process called osseointegration. During this period, molds are made to create a custom-fitted base for the prosthesis. The visible portion of the prosthesis is sculpted out of silicone, using the patient's other ear as a model. Tints are used to match the patient's skin tone, creating a remarkably realistic replacement.
Judging from the experience with dental implants, Dr. Wazen expects the skull implants to last for many years. However, patients must be careful to prevent infection by cleaning the skin around the implants daily.
Dr. Wazen uses the Branemark implant system, made by Nobel Biocare, a Swedish company. The system has been approved by the Food and Drug Administration. The same techniques can also be used to create prostheses for people with nasal or orbital defects.
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