Penn Otorhinolaryngology – Head and Neck Surgery’s division of Otology & Neurotology is one of only a few programs in the United States, and the only in the Philadelphia region currently offering patients intact skin, bone conduction implant systems classified as an active transcutaneous bone conduction implants. Indicated for individuals with conductive or mixed hearing loss originating in the middle or inner ear, these two implants are new alternatives with advantages over traditional percutaneous bone-anchored hearing aid devices.
“These new devices are high-performance hearing implants that work by conducting vibrations directly to the inner ear through the bones of the skull, by-passing the middle ear,” says Jason Brant, MD. Dr. Brant leads the Fellowship program in Otology & Neurotology and Lateral Skull Base Surgery at Penn ENT, and is a member of the implantable hearing devices treatment team.
Because there are no components that stick through the skin, these devices provide improved aesthetics and reduced risk of infection compared to traditional bone anchored devices because – unlike traditional percutaneous devices – the implanted portion of the device is entirely covered by skin. Further, the magnets needed to hold the external components on can be less powerful which reduces the risk of skin problems from prolonged pressure.
Both are offered at Penn Otorhinolaryngology as FDA cleared clinical devices as well as part of a currently accruing trials. “The reason PENN Otorhinolaryngology has access to new technologies like these has much to do with the high regard in both the industry and the otology community for our clinical research programs,” Dr. Brant adds.
Forms of Hearing Loss
The cause of hearing loss is either conductive or sensorineural, or a combination of the two-a condition described as mixed hearing loss. Hearing loss can also be one-sided or bilateral.
In conductive hearing loss, there is a reduction of sound wave conduction from the outer ear and/or middle ear to the inner ear. Conductive hearing loss can be the result of damage to the bones, or ossicles, of the inner ear, but there are many other reasons, including fluid in the inner ear, perforated ear drum, tumors and otitis media. All can affect the level of severity or the temporal profile of the patient’s hearing impairment.
Sensorineural hearing loss occurs at the ear’s sensory receptor, the organ of Corti, or the auditory nerve (cranial nerve VIII). Coiled inside the cochlea of the inner ear, the organ of Corti contains thousands of minuscule vibrating hairs connected to auditory nerve fibers that pass signals to the brain. Any imposition or damage to these delicate hair fibers brought about by congenital defect, ototoxic drugs, or sudden or prolonged exposure to very loud noise, can cause hearing loss. Similarly, damage to the cochlear nerve may blunt the nerve impulse or its transmission from the inner ear to the brainstem.
When elements of conductive and sensorineural hearing loss occur concurrently, the result is mixed hearing loss.
The Benefits of Active Transcutaneous Bone Conduction Implants: Restoring Hearing, Reducing Risks, and Improving Aesthetics
These devices were designed to treat individuals with conductive or mixed hearing loss originating in the middle or inner ear. They are generally not indicated for hearing loss that is the result of damage to the auditory nerve (hearing loss beyond the cochlea). But can be used for cases like this if there is near-normal hearing in the other ear – so called single sided deafness.
The conduction unit’s processor is implanted under the skin behind the ear. A low-profile audio processor is positioned directly over the implanted portion and held in place through light magnetic attraction. The microphones of the audio processor collect sound waves and coverts them into electrical signals. These signals are transmitted to the implant, where a signal converter transforms them into mechanical vibrations. These vibrations are then transmitted to the bone, which conducts the vibrations to the inner ear. The hairs of the inner ear vibrate and transmit this information to the auditory nerve. But Transcutaneous BAHA devices are not typical of the bone anchored devices that have been on the market for more than 40 years.
“BAHAs usually produce good hearing outcomes, but there are concerns with infection and wound management because the stem connecting the vibrator to the bone penetrates the skin,” says Dr. Brant. “While the new devices are anchored in bone, there is no penetrating stem, so much less risk of infection.”
Additionally, in patients with single-sided deafness where one ear has significant hearing loss but the other ear is normal or near-normal, these devices can be used to transmit sound vibrations from the non-hearing ear to the hearing ear.
“Beyond their efficacy, the new active transcutaneous systems’ greatest appeal for patients will be their appearance and the capacity to remove the transmitter when needed,” Dr. Brant says. “It really is a substantial advance in hearing implant technology.”
Interested in participating in the BONEBRIDGE clinical trial? Contact Michael Ruckenstein, MD, at 215.662.2777. Dr. Ruckenstein is the Vice Chairman of the Department of Otolaryngology and the Director of the Implantable Hearing Devices Program at Penn Medicine. You may also refer patients directly to Penn ENT using our referral form.
About the Penn ENT Implantable Hearing Device Program
Begun more than 30 years ago, the Implantable Hearing Device Program at Penn Otorhinolayrngology – Head and Neck Surgery provides more cochlear implants and bone conduction systems than any other center in the Philadelphia region. Staffed by world-renowned neurotologic surgeons and experienced implant audiologists, the Program offers surgical implantation for a diverse selection of devices, and device programming. The team averages more than 120 cochlear implants per year.
Penn Otorhinolaryngology has been a participant in research and clinical trials for many years. Through clinical research, the Department is involved in investigating ways to increase candidacy criteria and improve outcomes for those in need of implantable hearing devices.
References
1. Meriwether GB, Reid TH. An otological investigation of putative hearing loss. NEJM 2019; 14:204-215.