Complications in Children with Long-Term Cochlear Implants

Subjective and Objective Taste Change After Cochlear Implantation Systematic Review and Meta-Analysis

INTRODUCTION

There is a paucity of data reporting the rate of chorda tympani nerve injury during cochlear implantation (CI) surgery. To better provide clarity to patients and surgeons regarding the risk of taste change, we performed a systematic review and meta-analysis of prospective studies examining taste change after CI.

DATA SOURCES

PubMed, Embase, and Cochrane Library databases were queried.

METHODS

Databases were queried according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Search terms included "(chorda tympani OR gustatory OR taste OR chemosensory OR dysgeusia OR nervus intermedius) AND (cochlea OR cochlear implant OR cochlear implantation)." Prospective studies were included and further divided into "objective" and "subjective" assessments of taste dysfunction. A systematic review was performed for all studies. A random-effects model was used to compare studies with similar methods and patient demographics.

RESULTS

The initial database query yielded 2,437 articles, which were screened according to inclusion and exclusion criteria. Nine appropriate studies were identified, including 442 total patients-254 with subjective assessment and 271 with objective assessment of gustation. Seventeen of 144 patients (11.8%) reported short-term taste change (incidence = 0.09 [0.02-0.16], 95% confidence interval with pooled data). Twenty-six of 265 patients (9.8%) reported long-term taste change (incidence = 0.07 [0.01-0.13]). Objective results were heterogenous and therefore not amenable to pooled meta-analysis.

CONCLUSIONS

Taste change from chorda tympani nerve injury is a likely underrecognized complication of CI and may be the most common adverse consequence of CI surgery. Surgeons should counsel prospective patients on this potential complication and that the risk of taste change may persist longer than the immediate postoperative period.

The Risk of Meningitis After Cochlear Implantation: A Systematic Review and Meta-Analysis

OBJECTIVE

This study aims to estimate the rate of postoperative meningitis (both immediate and long-term) in patients following cochlear implants (CIs). It aims to do so through a systematic review and meta-analysis of published studies tracking complications after CIs.

DATA SOURCES

MEDLINE, Embase, and Cochrane Library.

REVIEW METHODS

This review was performed in line with Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Studies tracking complications following CIs in patients were included. Exclusion criteria included non-English language studies and case series reporting <10 patients. Bias risk was evaluated using the Newcastle-Ottawa Scale. Meta-analysis was performed through DerSimonian and Laird random-effects models.

RESULTS

A total of 116/1931 studies met the inclusion criteria and were included in the meta-analysis. Overall, there were 112 cases of meningitis in 58,940 patients after CIs. Meta-analysis estimated an overall rate of postoperative meningitis of 0.07% (95% confidence interval [CIs], 0.03%-0.1%; I2  = 55%). Subgroup meta-analysis showed this rate had 95% CIs crossing 0% in implanted patients who received the pneumococcal vaccine, antibiotic prophylaxis, those with postoperative acute otitis media (AOM), and those implanted less than 5 years.

CONCLUSION

Meningitis is a rare complication following CIs. Our estimated rates of meningitis after CIs appear lower than prior estimates based on epidemiological studies in the early 2000s. However, the rate still appears higher than the baseline rate in the general population. The risk was very low in implanted patients who received the pneumococcal vaccine, antibiotic prophylaxis, received unilateral or bilateral implantations, developed AOM, those implanted with a round window or cochleostomy techniques, and those under 5 years.

Comparison of Adult and Pediatric Cochlear Implant Wound Complications: A Meta-Analysis

OBJECTIVE

To compare age-related differences in wound complications following cochlear implantation (CI).

METHODS

We performed a systematic review of PubMed, Cochrane Database, and Web of Science databases to identify original research evaluating the patient-level factors (demographics and medical history) associated with wound complications following CI. Outcomes were expressed as relative risk (RR) with 95% confidence intervals using the inverse variance method. Studies without comparison groups were described qualitatively.

RESULTS

Thirty-eight studies representing 21,838 cochlear implantations were included. The rate of wound complications ranges from 0% to 22%. Patient age (adult versus pediatric) was the only factor with comparison groups appropriate for meta-analysis. The 10 studies (n = 9547 CI's) included in the meta-analysis demonstrated that adults had a higher incidence of overall wound complications (2.94%) than in children (2.44%) (RR 1.31, 95% CI 1.01-1.69). Adults had a higher incidence of general/unclassified wound complications (2.07%) than in children (1.34%) (RR 1.68, 95% CI 1.12-2.52). There was no difference between adults and children for specific complications such as hematoma, infection, or seroma. Elderly patients (over age 75) have wound complication rates that range from 1% to 4%. No studies contained comparison groups regarding other patient-level factors and CI wound complications.

CONCLUSION

CI wound complication rates reported in the literature are low; however, adults have a higher risk of these complications than pediatric patients. The reported complication rate in elderly adults is low. There is a gap in CI research in consistently reporting wound complications and rigorous research investigating the impact of patient-level factors and wound complications.

LEVEL OF EVIDENCE

NA Laryngoscope, 133:218-226, 2023.

Electrostatic Discharge (ESD) as a Cause of Facial Nerve Stimulation After Cochlear Implantation: A Case Report

OBJECTIVE

To discuss persistent facial nerve stimulation (FNS) related to repeated electrostatic discharge (ESD) shock following cochlear implantation.

METHODS

Single case report with literature review.

RESULTS

FNS is a feared complication after cochlear implantation, occurring in approximately 7% of cases, with most patients having anatomic abnormalities. The presented case has no anatomical abnormalities but reported frequent environmental static shock. FNS during the first 1 to 3 seconds of processor attachment caused a significant decrease in the patient's quality of life, requiring subsequent re-implantation with full resolution.

CONCLUSIONS

FNS is a complication of cochlear implantation that can cause a great deal of distress and discomfort. Frequent electrostatic discharge (ESD) contributed to device malfunctioning and FNS in a patient with otherwise normal anatomy and should be avoided if possible.

Meta-analysis of subjective complaints of vertigo and vestibular tests after cochlear implantation

OBJECTIVE

Postoperative vertigo is a common complaint after cochlear implantation, but published incidence rates differ vastly. The aim of the present study was to investigate both subjective complaints of vertigo before and after cochlear implantation and related vestibular diagnostic tests on cochlear implant candidates.

DATA SOURCES

We performed a systematic literature search according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses statement in PubMed, Cochrane Register, and EMBASE.

REVIEW METHODS

We presented 116 eligible studies investigating subjective complaints of vertigo after cochlear implantation and/or related vestibular diagnostic tests. We conducted three meta-analyses of 46 eligible studies with matched pre- and postoperative data to calculate the odds ratio of new vertigo onset, as well as the impairment of vestibular receptors measured by nystagmography and cervical vestibular evoked myogenic potentials (cVEMP). Postoperative vertigo was calculated from 95 studies and further subdivided by mean age with pooled data.

RESULTS

We observed a significant increase in postoperative vertigo and significant impairment of nystagmography and cVEMP detection. Vertigo after cochlear implantation was reported in 9.3% of the patients with a continuous increase in patient age at surgery. In a subgroup of studies, new onset of vertigo was found in 17.4% of the patients. In addition, 7.2% of the patients had persisting vertigo complaints, whereas 11.6% described an altered vertigo quality and 7.7% had their preoperative complaints resolved. A comparison of round window approach and cochleostomy revealed significantly increased vertigo after cochleostomy. Both insertion methods showed similar effects in nystagmography and cVEMP testing.

CONCLUSION

Cochlear implantation has a significant impact on subjective vertigo and vestibular receptor function. This is affected by the patient's age at the time of surgery. The surgical technique (round window or cochleostomy) may influence the outcome, but this requires further investigation. Younger patients may compensate better following vestibular dysfunction. Perioperative testing is required to correlate vestibular impairment and subjective complaints. Laryngoscope, 2018 Laryngoscope, 128:2110-2123, 2018.

Impact of Chronic Suppurative Otitis Media in Pediatric Cochlear Implant Recipients-Insight into the Challenges from a Tertiary Referral Center in UK

OBJECTIVE

Analyze the presentation and evolution of chronic suppurative otitis media (CSOM) in children with cochlear implants (CI) and explore the merit of early intervention.

STUDY DESIGN

Retrospective patient review.

SETTING

Tertiary referral hospital and cochlear implant programme.

PATIENTS

Children with a CI who developed CSOM.

INTERVENTION

Tympanoplasty.

MAIN OUTCOME MEASURES

Disease control, recurrence of cholesteatoma, cochlear implant preservation.

RESULTS

Eight children fit our inclusion criteria with a mean follow up of 8 years. Onset of CSOM symptoms was observed on an average of 5 years after implantation (range, 2-13 yr) and led to surgical intervention in an average of 15.6 months following symptom onset. Cholesteatoma was found in four of the eight patients. Of these, one patient underwent a subtotal petrosectomy and explantation with reimplantation at the same stage but the reimplant failed to function and was explanted subsequently. One patient was initially managed by a canal wall up mastoidectomy and explantation but went on to require subtotal petrosectomy and labyrinthectomy for recurrent disease. One patient underwent a subtotal petrosectomy with explantation and is awaiting a reimplantation. The fourth patient had limited disease around the electrodes that was excised without compromising the implant. In the group of patients with CSOM without cholesteatoma, one underwent an explantation due to recurrent ear infections and a subsequent cartilage tympanoplasty for a retracted eardrum. The remaining three patients underwent successful excision of retraction pockets and repair of eardrums using cartilage with the implant in situ. A mean follow up of 2 years after the implant preservation surgeries shows good functioning of the CI.

CONCLUSION

Early recognition of CSOM is paramount in patients with CI as delay in treatment can result in the infection spreading via the cochleostomy resulting in loss of the cochlea. Recurrent ear infections in an implanted ear should prompt early examination to exclude the presence of middle ear disease, which may require anesthesia in a young child.

Effects of Cochlear Implantation on Gustatory Function

Objectives:

Because of the anatomic position of the chorda tympani in the tympanic cavity, the nerve is at risk during cochlear implantation. The aim of this study was to assess changes in taste sensitivity and in self-ratings of gustatory function after surgery.

Methods:

Twenty-four patients (mean age, 54 years) who underwent cochlear implantation were investigated. Taste function was tested with a validated test for regional quantitative assessment of sweet, sour, salty, and bitter tastes on each side of the tongue before and 4 days after surgery.

Results:

The mean taste score was 10.0 (SD, 4.0) before and 8.0 (SD, 4.1) after surgery on the side of the tongue ipsilateral to the operated ear (p = .004). However, only 1 patient reported subjective taste loss due to surgery. Taste testing of the side of the tongue contralateral to the operated ear yielded a score of 10.0 (SD, 4.1) before and 10.9 (SD, 4.5) after surgery (p = .037). Self-ratings of gustatory function did not change significantly as a consequence of the procedure.

Conclusions:

Our results indicate that cochlear implantation is a relatively safe procedure regarding taste function. Preoperative testing of gustatory function is recommended, at least in those patients who already have undergone operation on the contralateral ear.

Comparisons of Auditory Performance and Speech Intelligibility after Cochlear Implant Reimplantation in Mandarin-Speaking Users

Objectives. We evaluated the causes, hearing, and speech performance before and after cochlear implant reimplantation in Mandarin-speaking users. Methods. In total, 589 patients who underwent cochlear implantation in our medical center between 1999 and 2014 were reviewed retrospectively. Data related to demographics, etiologies, implant-related information, complications, and hearing and speech performance were collected. Results. In total, 22 (3.74%) cases were found to have major complications. Infection (n = 12) and hard failure of the device (n = 8) were the most common major complications. Among them, 13 were reimplanted in our hospital. The mean scores of the Categorical Auditory Performance (CAP) and the Speech Intelligibility Rating (SIR) obtained before and after reimplantation were 5.5 versus 5.8 and 3.7 versus 4.3, respectively. The SIR score after reimplantation was significantly better than preoperation. Conclusions. Cochlear implantation is a safe procedure with low rates of postsurgical revisions and device failures. The Mandarin-speaking patients in this study who received reimplantation had restored auditory performance and speech intelligibility after surgery. Device soft failure was rare in our series, calling attention to Mandarin-speaking CI users requiring revision of their implants due to undesirable symptoms or decreasing performance of uncertain cause.

Acute Mastoiditis in Children with Cochlear Implants

Objective

Acute mastoiditis is an uncommon but challenging condition when it occurs in children with cochlear implant. The literature is scarce as to the management of this condition with regards to explantation. The objective of the study is to determine the need for explantation in patients with cochlear implants who suffer from acute mastoiditis.

Data Sources

Online medical databases—PubMed, Ovid Medline, Ovid Medline in process, Embase, Cochrane Library, CINAHL, Biosis, Google Scholar, and Scopus.

Review Methods

A systematic review of all publications addressing the treatment of mastoiditis in cochlear implant children prior to November 2013 was conducted. Data were collected from online medical databases—PubMed, Ovid Medline, Ovid Medline in process, Embase, Cochrane Library, CINAHL, Biosis, Google Scholar, and Scopus. The review was performed in 3 phases; an initial screening review of abstracts was performed, followed by a detailed review of full articles based on inclusion and exclusion criteria, and lastly a final review to extract data from selected articles.

Results

Twelve articles were found eligible for this systematic review including a total of 43 patients. Subperiosteal abscess was present in 14.3%. All patients received intravenous antibiotics as an initial treatment, and if needed, surgical intervention was performed. Only 1 patient required explantation (2.3%).

Conclusion

Prompt, aggressive medical and if needed surgical therapy can help in saving the implant and result in a favorable outcome.

Taste sensation following cochlear implantation surgery

OBJECTIVES

The chorda tympani nerve (CTN) is at risk of damage during cochlear implantation, especially during posterior tympanotomy. The aim of this study was, therefore, to elicit the risk of taste disorders following cochlear implantation surgery involving a mastoidectomy and a posterior tympanotomy approach.

METHOD

Twenty-six patients underwent a taste test before, 3 days after, and 6 weeks after cochlear implantation surgery. The taste sensations - sweet, sour, salt and bitter - were determined. Patients' self-ratings of taste function were also obtained. In addition, the surgeons provided information concerning the intraoperative status of the CTN.

RESULTS

In total, 19.2% (5 of 26) of the patients had postoperative taste dysfunction, as measured either subjectively or objectively or both. One of these five individuals had taste disturbance as assessed by both subjective and objective measures; in another, it was merely reported subjectively. Three patients were subjectively asymptomatic but the postoperative taste test revealed a dysfunction. Sixteen percent of the patients in whom the CTN was reported to be preserved intraoperatively had a postoperative taste dysfunction. Although the CTN was rerouted in five patients, only two of them (40%) had transient gustatory dysfunction. In two of those patients with postoperative taste dysfunction, the CTN was not intraoperatively exposed (being protected by bone) despite these individuals' experiencing postoperative taste problems. The recovery rate was 100% at 6 weeks after surgery.

CONCLUSION

Our study indicates that cochlear implantation entails only a minimal risk of taste dysfunction and that this is chiefly a transient problem.

Cochlear implants in children younger than 6 months

OBJECTIVES

(1) To determine the long-term outcomes of cochlear implantation in children implanted younger than 6 months and (2) to evaluate auditory-based performance in very young children compared with older children, all with profound sensorineural bilateral hearing loss.

STUDY DESIGN

Prospective cohort study.

SETTING

Tertiary referral center.

SUBJECTS AND METHODS

Twelve subjects aged 2 to 6 months, 9 aged 7 to 12 months, 11 aged 13 to 18 months, and 13 aged 19 to 24 months, all with profound bilateral hearing loss, were fitted with cochlear implants and followed longitudinally for 4 years. Subjects were developmentally normal with no additional disabilities (visual, motor, or cognitive). Auditory-based communication outcomes included tests for speech perception, receptive language development, receptive vocabulary, and speech production.

RESULTS

Age at cochlear implantation was a significant factor in most outcome measures, contributing significantly to speech perception, speech production, and language outcomes. There were no major complications and no significantly higher rates of minor complications in the younger children.

CONCLUSION

This article reports an uncontrolled observational study on a small group of infants fitted with cochlear implants following personal audiological criteria and, up to now, with limited literature support due to the innovative nature of the study. This study shows, for the first time, significantly improved auditory-based outcomes in children implanted younger than 6 months and without an increased rate of complications. The data from the present study must be considered as explorative, and a more extensive study is required.

Cochlear implantation in the very young child: issues unique to the under-1 population

Since the advent of cochlear implantation, candidacy criteria have slowly broadened to include increasingly younger patients. Spurred by evidence demonstrating both perioperative safety and significantly increased speech and language benefit with early auditory intervention, children younger than 12 months of age are now being successfully implanted at many centers. This review highlights the unique challenges involved in cochlear implantation in the very young child, specifically diagnosis and certainty of testing, anesthetic risk, surgical technique, intraoperative testing and postoperative programming, long-term safety, development of receptive and expressive language, and outcomes of speech perception. Overall, the current body of literature indicates that cochlear implantation prior to 1 year of age is both safe and efficacious.

Diagnostic challenges and safety considerations in cochlear implantation under the age of 12 months

AIM

To review the current knowledge on cochlear implantation in infancy, regarding diagnostic, surgical and anesthetic challenges.

STUDY-DESIGN

Meta-analysis. EBM level: II.

MATERIALS/METHODS

Literature-review from Medline and database sources. Related books were also included.

STUDY SELECTION

Meta-analyses, prospective controlled studies, prospective/retrospective cohort studies, guidelines, review articles.

DATA SYNTHESIS

The diagnosis of profound hearing loss in infancy, although challenging, can be confirmed with acceptable certainty when objective measures (ABR, ASSR, OAEs) and behavioural assessments are combined in experienced centres. Reliable assessment of the prelexical domains of infant development is also important and feasible using appropriate evaluation techniques. Overall, 125 implanted infants were identified in the present meta-analysis; no major anesthetic complication was reported. The rate of surgical complications was found to be 8.8% (3.2% major complications) quite similar to the respective percentages in older implanted children (major complications ranging from 2.3% to 4.1%).

CONCLUSION

Assessment of hearing in infancy is feasible with adequate reliability. If parental expectations are realistic and hearing aid trial unsuccessful, cochlear implantation can be performed in otherwise healthy infants, provided that the attending pediatric anesthesiologist is considerably experienced and appropriate facilities of pediatric perioperative care are readily available. A number of concerns, with regard to anatomic constraints, existing co-morbidities or additional disorders, tuning difficulties, and special phases of the developing child should be also taken into account. The present meta-analysis did not find an increased rate of anesthetic or surgical complications in infant implantees, although long-term follow-up and large numbers are lacking.

Cochlear implantation in the very young child: Long-term safety and efficacy

OBJECTIVES/HYPOTHESIS

Widespread universal newborn hearing screening has led to increased identification of infant hearing loss. Supported by improved diagnostic tools allowing more definitive diagnosis of profound sensorineural hearing loss in young children, cochlear implantation in children <12 months of age is now common. Literature supports short-term safety and improved auditory outcomes in these young children, however long-term data is lacking. The study examines issues of long-term safety and efficacy in cochlear implant patients implanted <1 year of age.

STUDY DESIGN

Retrospective chart review.

METHODS

Fifty children who received cochlear implants before 1 year of age were followed for up to 7 years. Age at implantation ranged from 5 to 11 months with a mean of 9.1 months. Three patients had simultaneous bilateral implantation at 8 to 9 months of age. Medical records were reviewed for complications incurred during length of device usage, including time of complication, management, and resolution. Auditory assessment included both the Infant-Toddler Meaningful Auditory Integration Scale and tests of speech perception.

RESULTS

All 50 patients had full insertions of the electrode array. There were a total of eight complications (16%) in seven patients, three major (6%) and five minor (10%), which occurred at or before 10 months postoperatively. There were no perioperative anesthetic complications.

CONCLUSIONS

Cochlear implantation in children <12 months of age is safe and efficacious over an extended period of time. Rates and nature of both major and minor complications are comparable to studies in adults and older children and support continued monitoring of these patients over the long-term.