UW Implants Hybrid CI

By CHERIE BLACK

Editor: The Virginia Merrill Bloedel Hearing Research Center at the University of Washington is one of the centers implanting the experimental hybrid CI. This article first appeared in their online newsletter at http://depts.washington.edu/hearing/pdf/bloedelsound.pdf

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Experimental surgery at UW offers a new remedy for hearing loss

Howard Davis was draped with white blankets and strapped to a table in Operating Room 2 at the University of Washington Medical Center. The only exposed parts of his body were his right ear and the right side of his face.

Of the nearly 30 million Americans who are hearing-impaired, about 50 percent to 60 percent fall into this category of hearing loss in which the two most common remedies aren't viable options, said Dr. Bruce Gantz, head of the Department of Otolaryngology -- Head and Neck Surgery at the University of Iowa.

Asleep under anesthesia, Davis, 61, had hoped to awaken to a chance at better hearing. He has suffered decades of gradual hearing loss attributed by doctors to the loud drills he has been using for years in his dental practice.

He has low-frequency hearing, meaning he can hear vowels, but has lost his high-frequency hearing, meaning he can't hear consonants. Understanding people when they talk to him is nearly impossible.

Hearing aids are inadequate because they just make the muddling sound patients hear louder, not clearer. The traditional cochlear implant -- which less than 5 percent of the hearing-impaired qualify for -- would damage whatever hearing the patients have left.

So Davis underwent an experimental surgery last week to implant a hybrid auditory device in his right ear as part of a newly approved Food and Drug Administration study.

The UW Medical Center is one of 20 sites in the United States and Europe involved in a clinical trial performing a total of 100 surgeries. So far 90 people have undergone the surgery worldwide. The UW performed three in January, Davis being the third.

First established at the University of Iowa, the hybrid auditory implant uses a shorter version of the traditional cochlear implant electrode. Surgeons and researchers hope to restore hearing without damaging the low-frequency hearing, which would happen with a traditional, longer cochlear implant.

For Davis, who said he avoids conversations and never does business for his dental practice over the phone, the chance at better hearing was worth any possible side effects.

"My children have learned to look at me when they talk so I can read their lips and I've just faked conversations before," he said. "I've gotten by and I don't want to do that anymore." Dr. Jay Rubenstein, director of the Virginia Merrill Bloedel Hearing Research Center at the UW, who performed the three surgeries there, called the hybrid idea "revolutionary" because, customarily, opening up the inner ear, as with this surgery, means destroying it. But in this case, because of the shorter implant and extreme caution, surgeons are able to "get away with it," he said.

The surgery's success could open doors for other potential surgical remedies for inner ear problems such as balance difficulties or ringing in the ear, he said.

During Davis' three-hour surgery, Rubenstein drilled into an area behind his right ear and implanted the device into a part of the cochlea that responds to high frequencies. The deliberate care in how far and where to drill consumed most of the surgery time.

Once the surgery is finished, patients are tested to see if their existing hearing is intact. All three patients who underwent the surgery at the UW still have their hearing, Rubenstein said, and the implant will be turned on in about three weeks, once healed from surgery.

All 100 patients will be tracked for one year to determine long-term success or failure.

Of the 90 patients implanted with the new device, three have been removed after patients lost hearing between three months to two years after surgery and weren't happy with the results, Gantz said. Six patients lost hearing, but are using hearing aids with the implant and still hear better than they did before surgery, he said.

In most patients, the surgery has been successful, with a patient's average word understanding increasing from 20 percent to more than 70 percent after having the implant for a year, he said.

"It's pretty impressive to take these patients and add the implant and all of a sudden they're in a hearing world," Gantz said.

Six-month data on 100 patients and one year data on 40 or 50 patients will be ready to present to the FDA in six to eight months, Gantz said.