Speech Recognition Outcomes After Cochlear Reimplantation Surgery

Implantation and reimplantation: epidemiology, etiology and pathogenesis over the last 30 years

INTRODUCTION

Due to the increasing number of cochlear implant (CI) recipients, growing indications, and the aging population, the reimplantation of CI recipients has become a focus of attention. The aim of this study is to examine the causes, timing, and postoperative speech understanding in a large cohort over the past 30 years.

METHODS

A retrospective data analysis was conducted on over 4000 CI recipients and 214 reimplanted children and adults from 1993 to 2020. This involved collecting and comparing data on causes, manufacturer information, and demographic data. In addition, a comparison of speech understanding in Freiburg monosyllables and numbers before and after reimplantation was carried out.

RESULTS

Children did not exhibit elevated rates of reimplantation. The overall reimplantation rate in the entire cohort was 5%. The CI overall survival rate after 10 years in the entire cohort was 95.2%. Device failure was the most common reason for reimplantation, with 48% occurring within the first 5 years after implantation. The second most common reason was medical complications, with the risk of reimplantation decreasing as more time passed since the initial implantation. There were no significant differences in Freiburg numbers and monosyllable comprehension before and after reimplantation, both in the overall cohort and in the subcohorts based on indications. Even a technical upgrade did not result in a significant improvement in speech understanding.

DISCUSSION

There was no significant difference in the frequency of reimplantation based on patient age, especially when comparing children and adults. Device failure is by far the most common indication for reimplantation, with no significant difference in implant survival between manufacturers. Patients most often choose the same manufacturer for reimplantation. The likelihood of reimplantation decreases with increasing time since the initial implantation. The indication for reimplantation should be carefully considered, as on average, no improved speech understanding is achieved, regardless of the cause, even with a technical upgrade.

Monopolar Electrosurgery With Cochlear Implants

OBJECTIVE

To evaluate safety of monopolar electrosurgery (MES) in patients with cochlear implants (CIs) by reporting outcomes of a series of patients who underwent MES after CI.

STUDY DESIGN

Retrospective case series.

SETTING

Tertiary referral center.

PATIENTS

Patients with indwelling CI subsequently undergoing surgery with operative note specifically detailing MES use.

MAIN OUTCOME MEASURES

Adverse outcomes in post-operative audiology/otolaryngology documentation; speech recognition scores.

RESULTS

Thirty-five patients (10 with bilateral CI) experienced 63 unique MES exposure events, 85.7% below and 14.3% above the clavicle. No adverse events or decreased performance due to MES use were reported for any patient. Pre- and immediate postoperative speech recognition scores were not significantly different for patients using either consonant-nucleus-consonant (CNC; n = 23, 68%-66%, p = 0.80) or AzBio (n = 15, 82%-88%, p = 0.60). For individual CNC performance, 21 (91%) patients demonstrated stability, 1 improved >15%, and 1 declined >15%, although this patient had become a non-user due to magnet issues and, after resolution of these issues, exceeded baseline pre-operative score. For individual AzBio performance, 12 (80%) patients demonstrated stability, 3 improved >15%, and none declined >15%.

CONCLUSIONS

No adverse events resulted from MES use in CI patients. Given the increased prevalence and expansion of indications for CIs, and widespread utility of MES, we suggest clarification and improved guidance from device manufacturers regarding safety and use of MES for patients with these devices. We hope that data regarding electrosurgery exposure events will better inform clinician decision-making with regards to relative benefits and risks for MES use for CI patients.

LEVEL OF EVIDENCE

4 Laryngoscope, 133:933-937, 2023.

HiRes Ultra Series Recall: Failure Rates and Revision Speech Recognition Outcomes

OBJECTIVE

To report Advanced Bionics (AB) Ultra (V1) and Ultra 3D (V1) cochlear implant (CI) electrode failures and revision speech recognition outcomes for patients at a large CI program.

STUDY DESIGN

Retrospective case series.

SETTING

Tertiary referral center.

PATIENTS

Patients receiving Ultra (V1) or Ultra 3D (V1) devices as of September 21, 2021.

MAIN OUTCOME MEASURES

Failure rate, revision surgery, speech recognition scores.

RESULTS

To data, 65 (21.1%) of the 308 implanted devices are known failures, with 63 (20.5%) associated with the recent voluntary field corrective action (FCA). Average time to failure was 2.2 ± 1.1 years. Fifty-two patients (82.5%) elected for revision surgery. Among adults, immediate prerevision scores demonstrated a significant decrease from best-achieved scores with the faulty implant, with mean difference of -15.2% (p = 0.0115) for consonant-nucleus-consonant (CNC) and -27.3% (p < 0.0001) for AzBio in quiet. By 3 months postactivation of the revised device, CNC (p = 0.9766) and AzBio in quiet (p = 0.9501) scores were not significantly different than best prerevision scores. Overall, 15 of 19 patients regained or improved their best prerevision CNC score. The current trajectory for FCA device failures is approximately 6% per year.

CONCLUSION

Compared to manufacturer reporting, a high number of patients experienced hard failures of the Ultra (V1) and Ultra 3D (V1) devices. Early identification of failures is possibly because of the diligent use of electrical field imaging testing. Most patients affected by the FCA regain or exceed their prefailure speech recognition score as soon as 3 months after revision surgery.

Scalar position, dislocation analysis and outcome in CI reimplantation due to device failure

Objective

Due to increasing indication for cochlear implantation (CI), reimplantation and technical upgrades their consequences are a special focus in CI surgery research. The aim of this study is to examine the indication and influences on both morphological position of the electrode array and audiological outcome following reimplantation.

Design

This is a retrospective analysis of adult CI patients reimplanted between 2004 and 2019. We evaluated the scalar position in pre- and postoperative cone beam computed tomography (CBCT) after CI and reimplantation and examined the indication for and the audiological outcome following reimplantation.

Results

The reimplanted patients showed stable and comparable audiological results for monosyllables and numbers for best fitted situation before and following reimplantation. Technical upgrades did not result in a significant improvement of speech perception. CBCT scans of reimplanted ears did not show significant increased rates of scalar dislocation or partial insertion.

Conclusion

Even with a technical upgrade, reimplantation does not improve speech perception outcome in CI patients. Therefore, the indication to reimplant should be approved critically. Reimplantation does not lead to a significantly increased risk for partial insertion, scalar dislocation or diminished electrode array insertion angle.

Cochlear Implant Failure in the Pediatric Population

BACKGROUND AND OBJECTIVES

In cochlear implant (CI) surgery, the results and causes of revision and reimplantation may guide surgeons in establishing surgical protocols for revision surgery with safe audiological outcomes. The aim of this study was to review our experience in terms of etiology, surgical strategy, and hearing outcomes in pediatric patients who underwent CI removal and reimplantation.

SUBJECTS AND PURPOSE

All patients received implants of the same brand. Pre and postoperative Categories of Auditory Performance score and aided free-field pure tone audiometry thresholds were noted. In vivo integrity tests were performed for each patient and the results of ex vivo tests of each implant were obtained from manufacturer.

RESULTS

A total of 149 CIs were placed in 121 patients aged <18 years. The revision rate in children was 6.7% (10/121 children). Six patients had a history of head injury leading to a hard failure. The causes of reimplantation in others were soft failure (n=1), electrode migration (n=1), infection (n=1), and other (n=1). All patients showed better or similar postreimplantation audiological performance compared with pre-reimplantation results.

CONCLUSIONS

It is very important to provide a safe school and home environment and educate the family for reducing reimplantation due to trauma. Especially for active children, psychiatric consultation should be continued postoperatively.

Rates, Indications, and Speech Perception Outcomes of Revision Cochlear Implantations

Revision cochlear implant (RCI) is a growing burden on cochlear implant programs. While reports on RCI rate are frequent, outcome measures are limited. The objectives of the current study were to: (1) evaluate RCI rate, (2) classify indications, (3) delineate the pre-RCI clinical course, and (4) measure surgical and speech perception outcomes, in a large cohort of patients implanted in a tertiary referral center between 1989–2018. Retrospective data review was performed and included patient demographics, medical records, and audiologic outcomes. Results indicated that RCI rate was 11.7% (172/1465), with a trend of increased RCI load over the years. The main indications for RCI were device-related failures (soft-45.4%, hard-23.8%), medical failure (14%), trauma (8.1%), and surgical failure (6.4%). Success rate was 98.8%. Children comprised 78% (134) of the cohort and were more likely than adults to undergo RCI. Most (70%) of the RCIs were performed within 10 years from primary implantation. Speech perception outcome analysis revealed unchanged or improved performance in 85% of the cases and declined performance in 15%. Current findings confirm that RCI is a safe with high clinical efficacy; however, the non-negligible percentage of patients that exhibited declined performance post-RCI should be considered in decision-making processes regarding RCI. Routine follow-up during their first years post-implantation is warranted.

Relationships between Intrascalar Tissue, Neuron Survival, and Cochlear Implant Function

Fibrous tissue and/or new bone are often found surrounding a cochlear implant in the cochlear scalae. This new intrascalar tissue could potentially limit cochlear implant function by increasing impedance and altering signaling pathways between the implant and the auditory nerve. In this study, we investigated the relationship between intrascalar tissue and 5 measures of implant function in guinea pigs. Variation in both spiral ganglion neuron (SGN) survival and intrascalar tissue was produced by implanting hearing ears, ears deafened with neomycin, and neomycin-deafened ears treated with a neurotrophin. We found significant effects of SGN density on 4 functional measures but adding intrascalar tissue level to the analysis did not explain more variation in any measure than was explained by SGN density alone. These results suggest that effects of intrascalar tissue on electrical hearing are relatively unimportant in comparison to degeneration of the auditory nerve, although additional studies in human implant recipients are still needed to assess the effects of this tissue on complex hearing tasks like speech perception. The results also suggest that efforts to minimize the trauma that aggravates both tissue development and SGN loss could be beneficial.

Revision pediatric cochlear implantation in a large tertiary center since 1986

Objective: To identify the rate of cochlear implantation (CI) re-implantation and assess audiologic outcomes. Methods: Demographic, audiometric, radiographic, and clinical data were collected from the medical records of the first 834 pediatric patients (age < 18) who underwent CI at a tertiary-care center. Results: Reviewing the first 834 pediatric patients who underwent CI between 1986 and 2013, 33 (4%) children have required re-implantation. Seven (0.8%) of these required a second re-implantation, for a total of 40 total revision surgeries (4.8%) and 21.1% of patients who underwent revision required multiple re-implantations. The mean age at initial CI was 3.5 years old, with identification of the failure an average of 2.7 years later (range, 0.1-10.1 years). The most common indications for re-implantation CI were unknown etiology (58%), vendor recall (18%), and trauma (9%). Twenty-three (88.5%) of the 26 patients who underwent only one re-implantation surgery achieved a complete insertion with both procedures. Eleven (91.7%) of 12 patients who had open set speech after their initial procedure maintained this after re-implantation surgery. Eight (38.1%) of 21 patients who did not have open-set speech after their initial implantation achieved open set speech with CI re-implantation. Conclusion: CI re-implantation is not common in the pediatric population. However, given the time-sensitive nature of speech/language development in children, with the right indications, CI re-implantation can be performed safely without compromising audiologic outcomes. However, re-implanted patients have an increased risk they will require re-implantation again in the future.

Evaluation of Subtotal Petrosectomy Technique in Difficult Cases of Cochlear Implantation

OBJECTIVES

To assess the validity of the subtotal petrosectomy (STP) technique in problematic cases of cochlear implant (CI) surgery, and review indications, outcomes, and related controversies.

STUDY DESIGN

This is a retrospective review of data from a private quaternary referral center of otology and skull base surgery.

PATIENTS AND METHODS

A review of patients who underwent CI with STP (STP-CI) as the leading approach was performed. Demographics, indications, surgical details, and main outcomes were evaluated. The surgeries performed were usually single-stage procedures encompassing a comprehensive mastoidectomy, blind sac closure of the external auditory canal (EAC), and mastoid obliteration with autologous fat.

RESULTS

A total of 107 cases were included. Mean follow-up was 7.1 years (range 1-13 years). The most frequent indication for STP-CI was chronic otitis media with/without cholesteatoma (32.7%), followed by open mastoid cavity (26.1%), and cochlear ossification (17.7%). Other difficult conditions where STP facilitates successful implantation include inner-ear malformations, temporal-bone trauma, unfavorable anatomic conditions, and revision surgery. A planned staged procedure was performed in 3 cases. The rate of major complications was 5.6% (n = 6). Three patients developed postauricular wound dehiscence which eventually resulted in device extrusion. No cases of recurrent/entrapped cholesteatoma, EAC breakdown, or meningitis were encountered. This is the largest single-center series of STP-CI reported in the literature.

CONCLUSIONS

When CI is intended in technically challenging cases or associated with a high risk of complications, STP is effective and reliable. Safe implantation and excellent long-term outcomes can be achieved provided surgical steps are properly followed. Single-stage procedures can be performed in most cases, even when there is active middle-ear disease.

Introducing the Australian Hearing Hub

This special issue contains a collection of papers highlighting the collaborative research taking place at Macquarie University's Australian Hearing Hub. Included in this introduction is a brief outline of the challenges in the hearing health and communication space and a brief description of the Australian Hearing Hub and its members, alongside an overview of the studies included in this special issue.