A cochlear implant is a device that bypasses the typical pathway of acoustic hearing and replaces it with electric hearing — or direct electrical stimulation of the hearing nerve. For many patients who are deaf or hard of hearing, cochlear implants are the best option to improve quality of life.
Part of the device is surgically implanted underneath the patient’s skin and is inserted in the inner ear behind the ear drum. The other part of the device visibly sits behind the ear and is not surgically implanted. While there are many benefits of receiving cochlear implants, these devices also have risks that potential users should be aware of before they decide to undergo surgery.
Vertigo or balance issues
As a result of cochlear implant surgery’s close proximity to several essential parts of the inner ear, some patients report a sense of imbalance or vertigo post-operation. There are a number of reasons that patients could suffer from vertigo following the surgery, including the vibrations caused by drilling during the surgery. Duration and severity of the balance issue can vary, and vestibular rehabilitation may be recommended, however, each patient’s case is unique. To determine the source of vertigo after surgery, patients should consult with their doctors.
After surgery, there is a risk of infection in the wound and/or the skin covering the implantation site. As with any wound post-surgery, it is important to take proper care of the incision. It is essential that you follow your doctor’s and implant audiologist’s orders to limit your risk of infection.
Facial nerve damage
The facial nerve lies close to the implantation site and the cochlea. Although rare, it is possible that the surgeon could accidentally damage the facial nerve implant surgery. Damage to the main branch of the facial nerve affects facial expressions and sensation, and damage to one of the branches of the nerve affects the way the patient experiences taste. Depending on the type and severity of the injury, it is possible that the damage done to the facial nerve may be rectified. However, in rare cases, the nerve injury can result in facial paralysis.
Bacterial meningitis — infection of the tissue and fluid the surround the brain and spinal cord — is one of the rarer but most serious complications of cochlear implant surgery. If untreated, it can be fatal. The patient’s risk for developing meningitis is correlated with the structure of the inner ear, but in general, all cochlear implant recipients have an increased risk of this infection compared to the general population. There are several ways to manage the risk of meningitis following CI surgery.
For instance, the patient should be up to date on all vaccinations recommended by the Centers for Disease Control and the U.S. Food and Drug Administration, and should follow his or her doctor’s post-surgery antibiotic plan very closely. The implant recipient should be seen by his or her surgeon if an ear infection is suspected. It is also important for the cochlear implant user to be fully aware of the symptoms of meningitis (stiff neck, fever, vomiting, grogginess, ear pain, etc.), and that person should see a doctor as soon as possible if the symptoms are present.
Loss of residual hearing
There was a point in the past when it was generally assumed that cochlear implant surgery would almost certainly result in the loss of any residual hearing in the implanted ear. This is now becoming less the case with advances in surgical techniques and new electrode designs that are intended to reduce damage to inner ear structures. However, preservation of existing hearing is not guaranteed, and there is still a distinct possibility that insertion of the electrode into the inner may result in the loss of all or some of the hearing function that was there prior to the surgery. Potential recipients should be comfortable with the notion of losing residual hearing prior to making a decision to proceed with surgery.
Tinnitus is the perception of a ringing or roaring sound in the ear when no sound is actually present. It is often associated with the existence of hearing loss. The development of new tinnitus or the worsening of existing tinnitus is a possible complication of cochlear implant surgery.
It is important for those considering surgery to understand how to care for the device after surgery as well as how to care for the incision. Having a comprehensive knowledge of the risks associated with cochlear implant surgery allows patients to monitor themselves for risk factors and for symptoms.
Jeff Simmons is the clinical coordinator of the Cochlear Implant Program at Boys Town National Research Hospital. Read more about him here.