A cochlear implant (CI) is a sophisticated medical device that provides a sense of sound to individuals with severe to profound hearing loss by bypassing damaged parts of the inner ear and directly stimulating the auditory nerve. The device is separated into two major components: an external sound processor that is worn outside the body, and an internal implant that is surgically placed under the skin. The question of whether a cochlear implant needs to be replaced depends entirely on which of these two distinct parts is being discussed. The external technology is routinely upgraded and replaced, but the internal implant is designed for long-term use and requires surgical replacement only in rare circumstances.
The External Processor: Maintenance and Upgrades
The external component of the cochlear implant, which includes the sound processor, microphone, and transmitting coil, is an advanced piece of digital technology. Unlike the internal component, the external processor is not surgically implanted and is fully exposed to daily wear and tear, necessitating routine replacement over time. The lifespan of the external processor is typically limited to between five and ten years, often closer to five.
Physical damage, such as from accidental drops, exposure to moisture, or cable degradation, can necessitate replacement before the end of the expected service life. More commonly, the driving factor for replacement is the pace of technological advancement. Newer processors offer improvements in sound processing algorithms, battery life, and connectivity options like Bluetooth. Manufacturers regularly release new generations of processors, and most insurance plans, including Medicare, may authorize an upgrade after five years to ensure the recipient benefits from the improved technology.
The Internal Implant: Intended Longevity
The internal component, consisting of the receiver/stimulator package and the electrode array inserted into the cochlea, is a surgically secured device designed for permanence. This component is hermetically sealed within a durable casing to protect the electronics from the body’s fluids. The long-term reliability is high, with reported cumulative survival rates often exceeding 96% at ten years and 91% at twenty years post-implantation.
Manufacturers provide long-term warranties for the internal component, often guaranteeing the device for ten years, reflecting its durability. The need for surgical replacement, known as revision surgery, is the exception rather than the rule. This high success rate results from advanced materials science and manufacturing techniques that ensure the internal electronics and electrode array remain stable within the inner ear environment for decades.
When Revision Surgery is Required
Surgical replacement of the internal implant, or revision surgery, is only undertaken when a problem arises that cannot be fixed by replacing the external processor. The most frequent reason is device malfunction, which accounts for a majority of revisions. This failure can be a “hard failure,” where the internal electronics completely stop working, or a “soft failure,” where the device’s performance gradually declines or produces painful stimulation.
Other causes for revision are related to medical or surgical complications, such as trauma from a severe head injury that damages the internal coil or receiver. Issues at the surgical site, including chronic infection, wound breakdown, or migration of the internal device, can also necessitate removal and replacement. Less commonly, the electrode array may be incorrectly positioned during the initial surgery, requiring a subsequent procedure for proper placement.
What Happens During an Internal Implant Replacement
An internal implant replacement procedure is similar to the initial implantation, though it can be more challenging due to scar tissue. The surgery is performed under general anesthesia and begins with an incision behind the ear to access the existing implant site. The surgeon carefully removes the old receiver/stimulator package and the electrode array from the cochlea.
A new, modern internal device is then secured under the skin, and its electrode array is threaded into the cochlea, which may require clearing away fibrous tissue. A primary consideration is ensuring the new implant is compatible with current and future generations of external sound processors. Recovery time is comparable to the original surgery, involving a short hospital stay and a healing period of several weeks before the new processor can be activated.