Revision cochlear implantation following internal auditory canal insertion

Management of Cochlear Implant Electrode Arrays Misplaced in the Internal Auditory Canal: A Systematic Review

OBJECTIVE

Misplacement of electrode arrays in the internal auditory canal (IAC) presents a unique clinical challenge. Speech recognition is limited for cochlear implant (CI) users with misplaced arrays, and there are risks with revision surgery including facial and/or cochlear nerve injury.

DATABASES REVIEWED

PubMed, Embase, and Scopus.

METHODS

A literature search was performed from inception to September 2023. The search terms were designed to capture articles on misplaced arrays and the management options. Articles written in English that described cases of array misplacement into the IAC for children and adults were included. The level of evidence was assessed using Oxford Center for Evidence Based Medicine guidelines. Descriptive statistical analyses were performed.

RESULTS

Twenty-eight cases of arrays misplaced in the IAC were identified. Thirteen (46%) were patients with incomplete partition type 3 (IP3), and 7 (25%) were patients with common cavity (CC) malformations. Most misplaced arrays were identified postoperatively (19 cases; 68%). Of these cases, 11 (58%) were managed with array removal. No facial nerve injuries were reported with revision surgery. Eight cases (42%) were left in place. Several underwent mapping procedures in an attempt improve the sound quality with the CI.

CONCLUSION

Electrode array misplacement in the IAC is a rare complication that reportedly occurs predominately in cases with IP3 and CC malformations. Removal of misplaced arrays from the IAC reportedly has not been associated with facial nerve injuries. Cases identified with IAC misplacement postoperatively can potentially be managed with modified mapping techniques before proceeding with revision surgery.

Posterior semi-circular canal electrode misplacement in Goldenhar's syndrome

Literature documents the incidence of electrode misplacement within the range of 0.2% to 5.8% with the superior SCC as the most common site, followed by the vestibule. In this report, we present the finding of electrode misplacement in the posterior SCC in a child with Goldenhar syndrome which was subsequently corrected. This child with bilateral congenital profound SNHL presented for unilateral cochlear implant surgery. Intraoperatively, the lateral SCC bulge, stapes, oval window, round window niche and pyramid were noted absent, leading to a surgical decision in favour of a subtotal petrosectomy. Using the aberrant facial nerve and jugular bulb as critical landmarks, a cochleostomy was performed in the posteroinferior aspect of the promontory bulge. Although electrode insertion was smooth and complete, NRT was absent in the presence of normal electrode impedance. A post-operative HRCT scan showed the electrodes in the posterior SCC. Repositioning of the electrodes was carried out by creating a new cochleostomy anteroinferior to the previous one. Complete correct electrode insertion was accomplished via this cochleostomy complimented by robust NRT tracings. Cochlear implant electrode insertion should be supported by correct identification of surgical landmarks. Intraoperative impedance testing and NRT help confirm device integrity and correct placement, the absence of which may raise the suspicion of malposition. In the presence of such a suspicion, the post-operative HRCT scan is a useful retrospective guide to corrective action, in a low-cost setting lacking intra-operative imaging facilities like X-ray, Fluoroscopy, Flat Panel CT & CBCT. Abbreviations, BERA: Brainstem Evoked Response Audiometry; CBCT: Cone Beam Computed Tomography; EAC: External Auditory Canal; ITD: Insertion Test Device; LSCS: Lower Segment Caesarean Section; MDT: Multi-Disciplinary Team; NICU: Neonatal Intensive Care Unit; NRT: Neural Response Telemetry; OAE: Oto-Acoustic Emissions; PIH: Pregnancy Induced Hypertension; SCC: Semi-Circular Canal; SNHL: Sensori-Neural Hearing Loss.

Systematic Review of Outcomes After Cochlear Implantation in Children With X-Linked Deafness-2

OBJECTIVE

Outcomes following cochlear implantation in children with X-linked deafness-2 are variable, resulting in challenges in appropriate preoperative counseling. To address this uncertainty, we performed a systematic review and synthesis of the literature on audiologic and speech outcomes after cochlear implantation in these patients to inform prognostic counseling.

DATA SOURCES

PubMed, Embase, and Cochrane Library were queried for articles published between January 2000 and July 2019.

REVIEW METHODS

We performed a systematic review of all studies published between 2000 and 2019 that reported on (1) children with confirmed X-linked deafness-2 undergoing cochlear implantation and (2) formal assessment of hearing and/or speech capabilities postimplantation.

RESULTS

Our initial database search yielded 313 articles. Fourteen articles met inclusion criteria. These studies reported on 61 children with X-linked deafness-2 who underwent implantation at a wide age range (1-29 years) for severe-profound sensorineural hearing loss of prelingual onset. The mean follow-up duration after implant activation was 32 months (range, 12-61). Outcome domains assessed at follow-up were heterogeneous, though each study employed at least 1 assessment of hearing (eg, pure tone audiometry), speech perception (eg, Early Speech Perception Test), or auditory perception (eg, Categories of Auditory Perception scores). In 10 of 14 studies, cochlear implantation afforded significant improvement in hearing and speech capabilities relative to preoperative performance or as compared with age-matched, normal-hearing controls.

CONCLUSION

The majority of studies demonstrate that cochlear implantation provides improvements in hearing and speech performance in patients with X-linked deafness-2. This information is valuable for decision making regarding cochlear implantation in these patients.

Outcomes of cochlear implantation in patients with incomplete partition type III

OBJECTIVE

To evaluate the outcomes of the surgery of cochlear implantation (CI) in patients with incomplete partition type III.

METHODS

Five patients (6 ears) with incomplete partition type III were performed CI from January 2010 and July 2018. Five ears were performed CI with extended round window approach. One ear was performed with round window approach.

RESULTS

The results of computed tomography (CT) showed proper placement of the electrode in 5 ears with extended round window approach. The electrode went into the internal auditory canal in one ear with round window approach. The scores of patients in the CAP and SIR assessment significantly improved after cochlear implantation in all patients during an follow-up period of 12 months.

CONCLUSIONS

CI with extended round window approach in patients with incomplete partition type III is a safe and effective method, but also a challenging task. This method maybe avoid the problem of electrode insertion into the IAC.

X-linked Malformation and Cochlear Implantation

OBJECTIVE

To evaluate if cochlear implantation is safe and constitutes an option for hearing rehabilitation of children with x-linked inner ear malformation.

STUDY DESIGN

Retrospective patient review in combination with a multidisciplinary follow-up.

SETTING

Tertiary referral hospital and cochlear implant program.

PATIENTS

Ten children with severe-profound mixed hearing loss and radiological findings consistent with Incomplete Partition type 3 cochlear malformation received cochlear implants during the years 2007 to 2015. Nine of the children had a mutation affecting the gene POU3F4 on Xq21.

INTERVENTION

Cochlear implantation.

MAIN OUTCOME MEASURES

Surgical events, intraoperative measures and electrical stimulation levels, hearing and spoken language abilities.

RESULTS

In all, 15 cochlear implantations were performed. In three cases the electrode was found to be in the internal auditory canal on intraoperative x-ray and repositioned successfully. One child had a postoperative rhinorrhea confirmed to be cerebrospinal fluid but this resolved on conservative treatment. No severe complications occurred. Postoperative electrical stimulation levels were higher in 9 of 10 children, as compared with typically reported average levels in patients with a normal cochlea. Eight patients developed spoken language to various degrees while two were still at precommunication level. However, speech recognition scores were lower than average pediatric cases.

CONCLUSION

Cochlear implantation is a safe procedure for children with severe-profound mixed hearing loss related to POU3F4 mutation inner ear malformation. The children develop hearing and spoken language but outcome is below average for pediatric CI recipients.

Cochlear Implantation in Inner Ear Malformations: Systematic Review of Speech Perception Outcomes and Intraoperative Findings

Objective

(1) To analyze reported speech perception outcomes in patients with inner ear malformations who undergo cochlear implantation, (2) to review the surgical complications and findings, and (3) to compare the 2 classification systems of Jackler and Sennaroglu.

Data Sources

PubMed, Scopus (including Embase), Medline, and CINAHL Plus.

Review Methods

Fifty-nine articles were included that contained speech perception and/or intraoperative data. Cases were differentiated depending on whether the Jackler or Sennaroglu malformation classification was used. A meta-analysis of proportions examined incidences of complete insertion, gusher, and facial nerve aberrancy. For speech perception data, weighted means and standard deviations were calculated for all malformations for short-, medium-, and long-term follow-up. Speech tests were grouped into 3 categories—closed-set words, open-set words, and open-set sentences—and then compared through a comparison-of-means t test.

Results

Complete insertion was seen in 81.8% of all inner ear malformations (95% CI: 72.6-89.5); gusher was reported in 39.1% of cases (95% CI: 30.3-48.2); and facial nerve anomalies were encountered in 34.4% (95% CI: 20.1-50.3). Significant improvements in average performance were seen for closed- and open-set tests across all malformation types at 12 months postoperatively.

Conclusions

Cochlear implantation outcomes are favorable for those with inner ear malformations from a surgical and speech outcome standpoint. Accurate classification of anatomic malformations, as well as standardization of postimplantation speech outcomes, is necessary to improve understanding of the impact of implantation in this difficult patient population.

Cochlear implantation in X-linked deafness - How to manage the surgical challenges

OBJECTIVE AND IMPORTANCE

In children with X-linked deafness, cochlear malformations challenge the implant surgeon to avoid electrode insertion into the internal auditory meatus and prevent a continuous cerebrospinal fluid (CSF) leak. We describe our experience of cochlear implantation (CI) in two children with profound hearing loss secondary to X-linked deafness, highlighting safer operative techniques to avoid potential complications.

CLINICAL PRESENTATION

Descriptive cases of two children with X-linked deafness (patient 1 and patient 2) undergoing CI. Peri-operative imaging and work-up to surgery are discussed. Specific operative considerations, post-operative complications and subsequent audiological performance are highlighted.

TECHNIQUE

In each case, intra-operative fluoroscopic imaging ensured intra-cochlear insertion of electrodes. Expected CSF gusher was seen in each case which was initially controlled by packing around the cochleostomy and array with temporalis muscle and fascia. Patient 1 developed post-operative meningitis secondary to continuous CSF leak. We avoided further significant CSF leak by planning staged procedures for patient 2, with obliteration of the middle ear cleft and external ear canal (EAC) at the time of implantation. In both patients, bilateral implantation successfully provided hearing thresholds of less than 35 dB in both ears at routine follow up.

CONCLUSIONS

When planning for CI in children with radiological features of X-linked deafness, intra-operative imaging should be utilized to ensure correct electrode positioning. Traditional methods of stopping a CSF gusher may not suffice. We therefore encourage additional surgical obliteration of the middle ear space and EAC to avoid persistent CSF leak and its associated complications.

X-linked deafness: A review of clinical and radiological findings and current management strategies

X-linked deafness is a rare genetic disorder causing a severe mixed hearing loss. This is due to an abnormal connection between the internal auditory meatus (IAM) and the basal turn of the cochlear leading to a “3^rd window effect” and cochlear conductive hearing loss. Patients are traditionally treated with conventional hearing aids however these are often unsatisfactory. Cochlear implantation is a high-risk procedure in such cases due to the risk of inadvertent electrode placement in the IAM. We present three paediatric cases where the hearing loss was managed with a combination of a bone anchored hearing aid in combination with a conventional behind the ear hearing aid. We also present a review of the current literature regarding the management of X-linked deafness.

Surgical techniques and outcomes of cochlear implantation in patients with radiographic findings consistent with X-linked deafness

OBJECTIVES

X-linked deafness is a potential etiology of sensorineural hearing loss characterized by bulbous dilatation of the fundus of the internal auditory canal (IAC) and the absence of the bony plates separating the basal turn of the cochlea and IAC. These malformations predispose patients to IAC insertion during cochlear implantation (CI). Our objective is to describe the surgical technique, audiometric and speech performance outcomes in a group of patients with this unique cochlear malformation.

METHODS

A retrospective chart review was performed of all patients at a tertiary care facility who underwent CI between January 2006 and July 2011.

RESULTS

A total of five patients were identified with radiographic findings characteristic of X-linked deafness, specifically a deficient modiolous, absent lamina cribrosa and bulbous IAC. A modified cochleostomy was utilized to ensure electrode insertion within the scala tympani avoiding the IAC. In each case, fluoroscopy was utilized to visual electrode progression during insertion and complete insertion was accomplished. All patients demonstrated improved speech performance following implantation.

CONCLUSIONS

Utilizing the techniques described, patients with these unique radiographic findings consistent with X-linked deafness may successfully undergo CI with excellent potential for auditory rehabilitation.

Positive Outcomes and Surgical Strategies for Bilateral Cochlear Implantation in a Child With X-Linked Deafness

OBJECTIVES

To recognize that bilateral cochlear implantation (CI) in X-linked deafness is safe, describe techniques to maximize successful electrode placement and minimize surgical risks, and recognize that normalization of hearing as well as language acquisition is achievable.

METHODS

A 6-month-old male patient presented with bilateral profound sensorineural hearing loss and was confirmed to have X-linked deafness secondary to POU3F4 gene mutation. Due to lack of benefit from amplification, he underwent bilateral CI in a staged fashion at 12 (right) and 15 months (left) of age. A transmastoid-facial recess approach was used bilaterally utilizing perimodiolar electrodes. High-flow gushers were controlled with muscle plugs. C-arm fluoroscopy was used during insertion of electrodes.

RESULTS

Follow-up data are available for 12 months. No complications were encountered, including no postoperative cerebrospinal fluid (CSF) leakage or facial stimulation. Postoperative audiograms in aided conditions showed hearing thresholds <40 dB. At 11 months following activation of his second CI, he scored in the normal range for his chronological age on standardized language measures.

CONCLUSION

With careful preparation and the assistance of intraoperative fluoroscopy, CI in patients with congenital X-linked deafness can be done safely. Performing bilateral CI followed by dedicated auditory-verbal rehabilitation may allow patients to achieve normal language development.