June 9, 1998
Johns Hopkins physicians have designed a series of implants that restore bulk to weakened vocal cords, returning the power of speech to those who have lost their voices from paralysis associated with throat cancers, strokes or other conditions. The patented implants were approved by the U.S. Food and Drug Administration in early spring.
The implants, shaped like the heads of tiny hammers, are made of hydroxylapatite, a chalk-like substance that melds into the body's tissue over time. Available in five sizes, the devices add volume to a weakened vocal cord, pushing it to the center of the voice box so it can meet its counterpart and produce sound.
Patients can lose the ability to speak when the nerve supply that normally pushes the cords together is lost. This condition affects about 5,000 to 10,000 people each year and can follow stroke or traumatic injury. It also can arise without an identifiable cause, says Charles W. Cummings, M.D., professor and chairman of otolaryngology-head and neck surgery. There are more serious complications, too.
"People who can't close their vocal folds cannot project their voices or trap air effectively, which makes it difficult to exercise or even walk upstairs," he says. "There is also a danger of choking on food, as the folds that normally protect the voice box can't close."
During a half-hour surgical procedure using local anesthesia, physicians drill a small hole in the side of the neck, creating about an inch-size opening in the thyroid cartilage to reach the vocal cord. Using specially designed instruments, they insert "sizers," or dummy devices of varying sizes and ask the patients to speak. When the patient recognizes his or her "correct" voice, the physicians remove the sizer and replace it with a same-size implant, locking it in place with a small shim of the same material.
"There's no greater thrill for both the patient and the doctor than to hear the patient speak again in his or her natural voice," Cummings says. "Patients can talk immediately following the surgery, but it may take up to six weeks for them to gain optimal pitch range."
Cummings and his colleague, Paul W. Flint, M.D., have used similar implants for about 10 years. Before the FDA's approval of their design, Cummings and Flint had to hand-carve an implant for each patient using sialastic, a less sturdy material. Having the pre-cut hydroxylapatite implants has cut their operating room time in half and helped reduce post-operative swelling.
Cummings and Flint perform about 80 of the procedures each year.