Cochlear Implant Surgery
A cochlear implant takes over the function of the cochlear which is no longer working effectively. The internal part of the implant has two main parts. The ‘receiver stimulator’ part and the ‘electrode array’ part.
The ‘receiver stimulator’ part is placed on the surface of the skull bone under the skin behind the ear. A bed is drilled into the skull bone to accommodate the receiver-stimulator and it is fixed to the skull with stitches.
The other part of the implant is the ‘electrode array’, which is like a wire, that runs from the receiver-stimulator package down through the mastoid bone, into the middle ear space under the ear drum and into the cochlea. In order for the electrode array to reach the cochlea a passageway needs to be created by drilling through the bone of the mastoid into the middle ear space where the outer surface of the cochlea can be seen. Getting into the middle ear space means drilling a slot in the bone between the facial nerve and the ear drum. The facial nerve supplies the muscles on one side of the face and is responsible for facial movement. Once the cochlea is exposed a hole needs to be drilled through the bony wall of the cochlea. The cochlea (the organ of hearing) is intimately related to the balance system.
The operation takes 3-4 hours for each implanted ear.
Cochlear implantation is a safe operation.
Complications are very uncommon. However, there are risks associated with any operation and whilst these will be explained to patients prior to the operation, they include:
- Facial nerve damage
- Wound infection
- Device failure
- An unpredictable outcome
- Implant damage
- Implant replacement
- Electrical nerve stimulation