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Cochlear Implant Complications Are Rare-But Can Be Lethal
From: ENT Today, August 2007
by Alice Goodman
Cochlear implantation has become a safe procedure-and, as result of refinements in devices and surgical techniques, complications are atypical. The major complication to be feared is meningitis, which is rare but potentially fatal. Other complications include device breakdown, flap breakdown, and local reactions at the site of implant, and these are manageable, agreed experts interviewed for this article. Although not all otolaryngologists perform cochlear implant surgery, it is important that all otolaryngologists be aware of the possible complications from this type of surgery.
Most surgeons think it is advisable to refer a patient who presents with a complication in the implanted ear to the original treating surgeon. Otolaryngologists are the gatekeepers of ear care. When faced with a problem from a cochlear implant, an otolaryngologist should not hesitate for one minute to call upon the surgeon who did the implant. Cochlear implant surgeons have a lifelong commitment to their patients, and the surgeon who did the procedure will be aware of unique issues related to that patient, stated Cliff Megerian, MD, Professor of Otolaryngology and Medical Director of the Cochlear Implant Program at University Hospitals of Cleveland and Case Western Reserve University School of Medicine in Cleveland, OH.
For any surgical complication, the patient should be referred back to the surgeon. Each surgeon differs a bit in technique, and the surgeon is the only person who is aware of unique patient factors, agreed Gerard J. Gianoli, MD, a neurotologist in private practice in Baton Rouge, LA, and Clinical Associate Professor of Otolaryngology and Pediatrics at Tulane University in New Orleans, LA.
Although it would be preferable, it is not always geographically feasible to refer patients back to the original surgeon, however, noted Samuel Levine, MD, Professor of Otolaryngology at the University of Minnesota in Minneapolis. He said that there are instances when patients have moved far away from the institution where they received a cochlear implant, and it is possible for the next surgeon to manage complications.
Complications Rare-But Meningitis Can Be Lethal
Dr. Megerian said that the lion's share of cochlear implants are performed by a handful of about 100 otolaryngologists in the United States. In his experience, complications are extremely rare. Dr. Gianoli said that although he performs only a few of these procedures each year, he has not seen any serious complications.
Meningitis, although rare, is an important exception. Although meningitis has been shown to occur in fewer than one of every 1000 patients who receive the implant, it can be life-threatening. Meningitis related to the implant can occur anywhere from one day to many years after surgery, Dr. Megerian said.
When a cochlear implant patient presents with ear pain and otitis media in the same ear as the implant, the clinician should be diligent in examining for signs of meningitis, such as fever, stiff neck, and lethargy. Any patient suspected of having meningitis should go to the ER for a lumbar puncture and be started on intravenous antibiotics, Dr. Megerian said. Immunization against S. pneumoniae and H. influenzae is used to prevent meningitis.
Dr. Megerian cautioned that even in the absence of signs of meningitis, any infection in the same ear as the implant should be treated aggressively. Once a person has had an implant, you need to be aggressive. The risk of meningitis is small, but it is a serious complication, he stated.
Less Worrisome Complications
Dr. Megerian was co-author of a recent review of complications of cochlear implants (Tambyraja RR et al. Arch Otolaryngol Head Neck Surg 2005;131:245-50), which was based on the FDA's Manufacturer and User Facility Device Experience (MAUDE) database. He and his colleagues studied two time periods: pre-1998 and the year 2002. The most common complication to occur during both time periods was device failure: 74/129 (57%) pre-1998 and 267/654 (41%) in 2002. Device failure should be suspected if a patient reports that the implant has stopped working, or that he or she felt a shock. The otolaryngologist needs to make sure the device is turned on; then the patient should be referred to the cochlear implant team. If the implant stops working over time, it can be replaced, Dr. Gianoli noted.
Other complications include wound/scalp/flap problems at the site of implant. These can take two forms: implant extrusion or the flap pulling apart and becoming vulnerable to infection. Again, Dr. Megerian emphasized the need for aggressive treatment with intravenous antibiotics at any sign of infection.
The good news is that from 1998 to 2002, the rate of wound flap problems was reduced. This is likely due to the movement toward a smaller incision, Dr. Megerian commented.
Other complications may include pain in the area over the magnet. The skin may be pulled too tight and cause redness in the magnet area. This would signal the need for a weaker magnet, Dr. Megerian said, which would prevent a scalp infection down the line.
Facial nerve injury is a very rare occurrence, but facial nerve stimulation by the device is fairly common in patients with a cochlear implant, said Dr. Gianoli. The electrode goes through the facial recess, and the current can stimulate the facial nerve. This is easily handled and does not impair the success of the procedure, he observed. If there is evidence of facial nerve stimulation, the audiologist who programs the implant can turn off one or two of the electrodes, which usually solves the problem. Explantation and implantation are rarely necessary, Dr. Gianoli said.
Leaks of cerebrospinal fluid are occasionally seen at the site of device placement and through the cochlea, Dr. Gianoli continued. This generally occurs in patients with a congenital malformation of the cochlea and can be fixed by plugging up the leaks with tissue, he said.
In general, Dr. Megerian expressed confidence in the procedure and said that there is no evidence that the inner or middle ear is more vulnerable to infection in a child or adult with a cochlear implant. In the overwhelming majority of cases, there are no problems and complications, he said.
In 2006, 71 cochlear implant procedures were performed at university hospitals in Cleveland. Of these, there was one complication in a child who sustained a severe head injury near the ear with the implant, and the implant had to be replaced. Dr. Megerian said that a few of the 71 patients had implants that stopped working and had to be replaced.
Refinements in quality control have reduced the incidence of device failure dramatically, Dr. Megerian said. He said that he has not seen any failures with the Nucleus Freedom device. (Dr. Megerian has no financial interest or affiliation with the Cochlear Corporation, manufacturer of the device.) Other companies are doing a good job producing high-quality devices, he said.
Series of Pediatric Patients
A study reported at the recent Triological Society meeting described complications in a series of 247 cochlear implants in pediatric patients treated at the University of Minnesota from 1986 to 2006. Seventeen major complications were identified, for an incidence of 6.9%, which is similar to other reports in the literature, said Dr. Levine, who was a coauthor of that abstract. Sixteen of the 17 cases required explantation and reimplantation, and 11 of these were successful. This series identified a new risk factor, which is congenital syndromes involving deafness; children with these syndromes were more likely to suffer complications and to have a worse outcome than children who did not have these syndromes, Dr. Levine explained.
We were lucky because our patients tend to stay in the same geographical area and enabled 20-year follow-up. Our findings provide a good picture of complications in pediatric cases. The basic pathology has remained the same over 20 years and so has the basic surgical technique, he commented.
Acceptance by the Deaf Community
Before 1995, there were justifiable concerns about the wisdom of performing cochlear implant surgery in a child who was born deaf, because of the possibility that the implant would interfere with the development of normal language skills. An article published in 1996 laid that fear to rest with a study showing that 90% to 95% of children with an implant will develop an open set of language skills, Dr. Megerian said.
Most opposition [to cochlear implants] from the deaf community has died down. Most children who are born deaf have normal hearing parents, and the parents make decisions about whether to have an implant, he commented.
Dr. Gianoli said that in the past, some activists in the deaf community considered deafness a culture, not a disability, and believed that having a cochlear implant separated the child from the deaf community. But this type of opposition is dying down. In the beginning, cochlear implants weren't popular, but the results are so fantastic with new advances that there is little opposition, he said.
Dr. Levine believes that members of the younger generation are more likely to accept the idea of cochlear implants than older people. He said that the accumulation of experience with implants in deaf children has alleviated much of the concern.
©2007 The Triological Society