The Envoy Esteem is a new totally implantable middle ear device.

Instead of a microphone, a transducer is placed on the incus.and the vibrations of the tympanic membrane and ossicular chain are detected by this transducer. The signal is amplified by the processor and transmitted via a transducer placed on the stapes to the cochlea.

The device is indicated for adults with moderate to severe sensorineural hearing loss. The hearing loss should be non-progressive, the middle ear anatomy should be normal, and speech perception scores should be better than 40% at 80dB SPL.

Advantages include:
Aesthetic appearance- no exteranl parts.
Unaffected by dust or water etc.
Patient able to swim with it.
Effective- in one study 56% of recipients preferred it to their previous hearing aid.

Disadvantages:
 It is not licensed for use in children.
It is not MRI compatible.
The risks of surgery seem rather high, although this may be due to a “learning curve”.
The battery needs to be surgically replaced after 5-9 years.
Residual hearing is NOT preserved- during surgery the incus has to be divided to prevent feedback. If the device is turned off, the natural hearing will be impaired. If the device is removed, ossiculoplasty surgery will be required to repair the divided incus.
Cost: The total cost for the device, surgery, programming etc. is approximately $33,000.