Cochlear implants in children: what constitutes a complication?

Cochlear Implant Reliability: On the Reporting of Rates of Revision Surgery

The aim of this study was to determine the magnitude of the risks associated with cochlear implantation. Results from a pool of thirty clinical studies involving cochlear implantation in over 6300 children were obtained from an internet search. The relevant data were transformed to a common time base (patient time) to allow an evaluation of events following implantation. The main outcome measure was cumulative survival probability for all-cause revision surgery. Over 10 years this was estimated to be 0.71. Thus, at 10 years post-implantation close to 30% of children with unilateral implants will have undergone revision surgery. This figure is considerably greater than that commonly reported for overall revision rates and illustrates the importance of interpreting results with respect to the relevant time frame. When non and low-use is incorporated into the analysis the above figure rises to about 37% of children affected. The findings raise concerns about the information provided to both individuals and regulatory bodies regarding the risks associated with cochlear implantation. The consequences for bilateral implantation are apparent. Our recommendations are i) a full disclosure to parents and children of the true magnitude of the risks and ii) for a body with significant expertise in reliability and systems engineering, and no conflicts of interest, to play a major role in the regulatory management of this service.

Endocochlear inflammation in cochlear implant users: case report and literature review

OBJECTIVES

Cochlear implantation is a relatively safe procedure with a low complication rate. The overall rate of complications among cochlear implant patients ranges from 6% to 20%. Major complications are those that are life-threatening or require surgery, whereas minor complications are those that can be medically treated. Nonetheless, certain complications, even if highly rare, may require specific investigations and treatments. Among these rare complications are those with endocochlear involvement, such as cochleitis or labyrinthitis, with fibrosis or ossification that could lead to explantation. The aims of the present study were to report a particular case of post-operative cochleitis and to review the rate of complications after cochlear implantation, emphasising those conditions with proven endocochlear involvement.

METHODS

We refer to the case of an eight-year-old Italian boy affected by the sudden onset of headache, ipsilateral otalgia and facial paresis, who presented to our clinic for inexplicable worsening of the performance of his implant and his residual hearing, six years after surgery. A complete investigation including (clinical history, routine, autoimmune and serological blood tests, electrophysiological measurements from the cochlear implant and neuroimaging) was performed and is herein described. Additionally, a comprehensive review of the literature was conducted using internet search engines; 274 papers were selected, 88 of which were best suited to our purposes.

RESULTS

In our case, the progression of the symptoms and the performance decrement required explantation, followed by a complete recovery. Reviewing the literature revealed only three reports concerning cases of proven endocochlear phlogosis that required revision surgery. Wound swelling/infection and vertigo remain the two most common complications of cochlear implantation. Failure of the device is the third most frequent complication (10.06% of all complications and 1.53% of cochlear implantations). Other rare conditions (such as granulating labyrinthitis with cochlear fibrosis, ossification and erosion, silicone allergy and the formation of a biofilm around the internal device) are possible and unpredictable. Although rare (approximately 1%), such cases may require explantation.

CONCLUSIONS

Despite efforts by both surgeons and manufacturers, device-related and surgical complications still occur. These and other rare conditions demand specific management, and their frequency may be underestimated. Further studies are needed to assess more realistic rates of complications and devise more efficient strategies for early diagnosis and treatment.

A Study of Complications and Morbidity Profile in Cochlear Implantation: The MERF Experience

Cochlear implantation (CI) has been established worldwide as the surgical treatment for individuals with bilateral severe to profound hearing loss. This is a safe and standard procedure in the hands of experienced implant surgeons. Complications due to surgery are minimal and are often encountered in cases with congenital anomalies of the temporal bone and inner ear. Complications in CI are related to malfunctioning of the device or the process of wound healing. In most cochlear implant centers, as the surgeon's skill and clinical expertise in managing various cochlear implant cases improves with years of experience, the complication rates in his series ideally come down over time. Over the years, these well experienced clinics become tertiary referral centers for CI, receiving many difficult cases for implantation and hence such centers report data on complications, which become an important reference for many aspiring implant surgeons. Our study, performed in a premier CI centre in Chennai, looks at the various complications which were encountered in a case series of 300 implantees. Retrospective descriptive study with data collected from operative notes, patient questionnaires, auditory habilitation registers and medical records of cochlear implantees operated between, November 2006 to November 2010. A spectrum of major and minor complications, were categorized. Their incidence rates in relation to the demography of the patient profile and various events during surgical procedure were documented and analyzed. Appropriate management protocols were defined. Our management protocols have been highlighted and the relevant literature reviewed. This report of our experience with 300 cochlear implantees, reveals that complication rates at our center are in comparison with reputed centers worldwide. CI is very safe in the long term and provides optimal auditory awareness with speech perception and intelligibility for profoundly deaf individuals giving them an avid opportunity to integrate within the normal society.

Paediatric cochlear implant durability: the Nottingham experience

OBJECTIVE

To determine durability of cochlear implant devices in a large paediatric cohort.

DESIGN

Retrospective review of database records of children consecutively implanted between 1989 and March 2002.

METHODS

The records of 363 children were studied. The review examined cases requiring explantation of the implant device for device failure with or without reimplantation.

RESULTS

15 failures were identified. The failure rates based on failures per number of implanted devices as well as cumulative user experience were 4.0% and 0.8% respectively.

CONCLUSIONS

As implant programmes grow, so will the number of children requiring device explantation and reimplantation. This will have implications on implant programme development and resource allocation.

Clinical outcomes of cochlear reimplantation due to device failure

Objectives

The aim of this study was to evaluate the clinical features of cochlear reimplantation due to device failure.

Methods

The medical records of 30 patients who had undergone a revision cochlear implantation were retrospectively reviewed. Causes of revision operations, number of electrode channels inserted, and postoperative speech performances were analyzed.

Results

Device failure (N=12, 38.7%) and hematoma (N=3, 9.6%) were the two most common reasons for revision surgery. In patients with device failure, the number of electrode channels reinserted was equal to, or more than the number of channels inserted during initial implantation. Speech performance scores remained the same, or improved after reimplantation in patients with device failure.

Conclusion

Device failure was the most common cause of revision operation in patients with cochlear implanttion. Contrary to expectation, new electrodes were fully inserted without difficulty in all reimplantation cases. Intracochlear damage due to reimplantation appeared to be clinically insignificant.

Migration of Cochlear Implant Magnets after Head trauma in an Adult and a Child

Cochlear implantation is considered to be a safe and effective treatment for severe to profound sensorineural hearing loss. Device failures are rare. We report the cases of 2 patients—a 44-year-old woman and a 3-year-old boy—with cochlear implants who were referred to our tertiary cochlear implant center for treatment of magnet migration secondary to mild head trauma. The migration had led to device failure in both cases. Surgical re-exploration was performed with nonmagnetic instruments, and both magnets were easily returned to their proper place. Postoperatively, implant function was restored to previous levels, and wound healing was uncomplicated. The incidence of magnet migration in cochlear implant patients is unknown. A few cases have been reported in children, but to the best of our knowledge, ours is the first report of magnet migration in an adult.

Revision surgeries in cochlear implant patients: a review of 45 cases

The aim of this study was to analyze the causes for revision procedures, surgical findings and audiological outcome in reoperated cochlear implant patients. The medical records of 45 patients were reviewed retrospectively for age at the time of implantation, the implant was used for initial and revision surgeries, the duration of implant use before revision, surgical findings, and postoperative audiological results. Generally, children were reoperated more often than adults (12.5 vs. 6.9%) and, with one exception of improper electrode insertion, there were no major post-revision complications. Device failure (DF) was the main cause for revision surgery (23/45) followed by wound/flap problems, magnet/receiver-stimulator displacement, foreign body/allergic reaction, subperiosteal abscess, misplaced electrode, intractable vertigo, cholesteatoma and extrusion of the positioner. No significant difference was found in the rate of DF between children and adults for each implant separately (P = 0.289 for Nucleus 22, P = 0.355 for Nucleus 24, P = 0.683 for Clarion and P = 1.0 for Med-El). The failure rates of different implants did not differed significantly among adults. DF in the Clarion group was significantly higher compared to the Nucleus and Med-El combined for pediatric patients (P = 0.0218) and all CI recipients (adults + children; P = 0.0055). The post-revision audiological benefit was unchanged or improved compared to the initial implantation values in all reimplanted patients and was not influenced by minor surgical procedures (wound revision, drainage of any collection, magnet replacement, or relocation of receiver-stimulator). Since DF was found to be the most common cause for reoperation, improving device technology could prevent the vast majority of revision procedures.

[Cochlear implants using the Ultracision harmonic scalpel]

We have evaluated the utility, indications and disadvantages of the Ultracision harmonic scalpel, in the cochlear implants, and his advantages compare to other electrocoagulation's systems. These aspects were evaluated in 50 cases of cochlear implants, made along the last years. We concluded that the Ultracision harmonic scalpel is indicated, mainly, in the otology field, in these situations in wich the cochlear implant is in the cochlea, and is mandatory the use of an electrocoagulation system. In this situation, the Ultracision harmonic scalpel was quick, safe and sure, and with many advantages, over the traditional scalpel and the bipolar diathermy.

[Cochlear implants in Aragón]

Cochlear implants are, actually, one of the major advances in the treatment for profound deafness. His use is, already, a routine in the daily practice of our specialty. Due to its special aspects, cochlear implants have to be done following a protocol that organizes and coordinates the different aspects of the diagnoses and treatment of profound deafness, in the different administrative and geographical fields. The health system in our country and the smale dimension of our area, has taken us to create and follow a special program in which all the available resources are used. Following this protocol, we have performed 63 cochlear implants, in the last 10 years. We show here the results and complications.

[Complications of cochlear implant surgery]

During the last several decades, cochlear implant has been fully recognized in treatment of severe hearing loss. Development of modern technology enabled inconceivable possibilities of technical qualities of the device as well as development of usable coding strategies, which led to extraordinary results in patient rehabilitation. Although cochlear implantation has become one of the routine operative procedures throughout the world nowadays, it gives rise to certain complications. These complications, though rare, can sometimes be very serious, even with fatal outcome. If cochlear implantation is performed by experienced and well-educated team of experts, the possibility of complications is minimal and is certainly not the argument against cochlear implantation as a method of treatment of severe hearing impairments.

Chronic Pseudomonas Infections of Cochlear Implants

OBJECTIVE

To discuss chronic, refractory Pseudomonas infections of cochlear implants and their management.

DESIGN

Retrospective case series.

SETTING

Two university-based cochlear implant programs.

PATIENTS

Twenty-eight-year-old (Case 1) and 4-year-old (Case 2), different devices.

INTERVENTIONS

Medical and surgical management.

MAIN OUTCOME MEASURES

Clinical course.

RESULTS

Both patients had delayed presentations, 4 months and 3 years postimplantation, respectively, with fluctuating scalp edema and pain resistant to multiple courses of oral antibiotics. Infections began as localized granulation and progressed to complete encasement of both devices with rubbery, poorly vascularized tissue. In each case, two different strains of multiresistant Pseudomonas aeruginosa were cultured. Infections progressed despite local debridement and targeted antipseudomonal antibiotic coverage, and sensitive organisms continued to appear in cultures of refractory granulation tissue. Both patients underwent partial explantation, with the electrode array left in the cochlea, then received 2 to 3 more months of further medical therapy and observation and then were reimplanted successfully with new devices. Both have shown excellent performance and no sign of recurrent infection.

CONCLUSIONS

Infections of cochlear implants are uncommon, and cases of successful conservative management without device explantation have been reported. However, our experience and the implanted device literature suggest that chronic Pseudomonas infections may represent a distinct clinical entity, likely to fail protracted therapy and ultimately require device removal. Fortunately, successful reimplantation is possible.

Epidural Hematoma After Cochlear Implantation In A 2.5-Year-Old Boy

OBJECTIVE

Report a case of an epidural hematoma after cochlear implantation in a 2.5-year-old boy, the diagnostic and therapeutical emergency management, as well as the postinterventional course and rehabilitation of the child.

STUDY DESIGN

Retrospective case review.

PATIENT

Two and a half-year-old boy, suffering from early onset, profound sensorineural hearing loss had been diagnosed at an age of 1.5 years, which had been more severe on the right side initially, but had progressed to bilateral deafness. INTERVENTION AND COMPLICATION: Cochlear implantation on the left side, followed up by an extensive epidural hematoma, causing intracranial compression with a midline shift of 15 mm to the right side. This initial complication was followed up by arterial infarction not only of the middle but also the posterior as well as the anterior cerebral artery, most likely caused by incarceration through the tentorium.

RESULTS

After immediate neurosurgical intervention and intensive care treatment including low-dose anticoagulation and high doses of corticosteroids, the child recuperated completely within 3 weeks without any remaining neurologic deficits.

CONCLUSION

In cochlear implantation, especially if placement of the implant housing is associated with considerable bone work, epidural hematoma has to be considered as an extremely rare, but life-threatening, complication.

Cochlear Implant Fixation Using Polypropylene Mesh and Titanium Screws

HYPOTHESIS

Fixation of cochlear implants using prosthetic mesh is an improvement of the traditional fixation methods.

STUDY DESIGN

A retrospective chart review was performed examining all adult and pediatric patients between 1998 and 2003 who underwent cochlear implantation using polypropylene mesh and titanium screws to fix the cochlear implant internal receiver. Patient age at implantation, postoperative infections, device failures, device migrations or extrusions, cerebrospinal fluid (CSF) leaks, flap complications, epidural hematoma data, and follow-up data were evaluated.

RESULTS

Two hundred and eighty-five patients were identified who received cochlear implantation using the polypropylene mesh securing technique. There were five postoperative infections, two device failures, zero flap complications, zero device migrations or extrusions, zero cerebral spinal fluid leaks, and zero epidural hematomas. The two delayed device failures in this series were not related to fixation technique.

CONCLUSIONS

We conclude that this technique is widely applicable, technically superior, and not associated with increased complications.

Semilongitudinal and axial CT planes in assessing cochlear patency in cochlear implant candidates

OBJECTIVE

To investigate how cochlear patency as seen on computed tomography (CT), using axial plus semilongitudinal planes, is correlated with findings at surgery in cochlear implant patients.

METHODS

Pre-operative CT scans of 45 patients were reviewed by three, independent observers. They classified the cochlear patency and recorded the location of any suspected decreased patency. The results were compared with the findings noted during surgery.

RESULTS

In nine patients a decreased cochlear patency was found at surgery. The sensitivity and specificity of CT assessment were, respectively, 56-33-11% and 100-86-94%. The interobserver reproducibility is reflected in a mean kappa of 0.46. The sensitivity increased when only patients suffering from post-meningitic deafness were considered.

CONCLUSION

Our study suggests that CT scans can be useful in assessing cochlear patency, especially in patients with post-meningitic deafness. This good performance might be explained by the combined use of scans in semilongitudinal and axial planes.

Cochlear implant failure: imaging evaluation of the electrode course

Cochlear implant (CI) is an electronic device used to rehabilitate patients with sensorineural hearing loss. The intent of this review is to demonstrate the normal position of the electrode on computed tomography (CT) and contrast this with various examples of the electrode malpositioning. Post-implantation CT is performed to localize the cause of implant failure in patients in which radiographs suggest an anomalous course of the electrode. A common cause of device failure is extrusion or malpositioning of the electrode. It is important for the radiologists to recognize this important aspect of device failure. Post-implant CT can help identify patients with malpositioned electrode in whom another attempt can be made by correctly re-implanting the electrode.

The potential risk of carotid injury in cochlear implant surgery

BACKGROUND

The advent of cochlear implantation has revolutionized the options afforded to the deaf population. With the increase in the prevalence of this procedure have come larger experiences in the associated technical challenges and complications.

RESULTS

We present the evaluation and management of a patient with an unusual complication of improper placement of the implant electrode into the carotid canal and its management. We discuss the anatomy of the carotid artery and its proximity to the cochlea to emphasize the potential risk to this large vessel.

CONCLUSIONS

Damage to the carotid canal and the carotid artery is a potential risk of cochlear implant surgery. When available, we recommend intraoperative electrical testing of the cochlear implant be performed. If there is doubt as to the placement of the electrode, a radiograph should be obtained before the patient is taken out of the operating room to avoid this complication.

Cochlear implants in children

Cochlear implants are electronic prostheses that provide a high quality sense of hearing to severely and profoundly deaf children and adults. As improvements in surgical technique and device performance have occurred, indications for implantation have expanded.