Incomplete partition type III (IP III) represents a rare malformation of the inner ear, posing challenges during cochlear implantation due to inevitable cerebrospinal fluid (CSF) leaks and the potential misplacement of electrodes within the internal auditory canal (IAC). Despite the absence of a consensus on electrode selection, literature suggests both straight and perimodiolar electrodes as viable options for proper insertion. Limited implantation series contribute to the ambiguity in electrode choice. In this study, we evaluated the insertion performance of three electrode types in a 3D model simulating an IP III patient's inner ear.

A 3D model replicating the inner ear of a patient with IP III undergoing surgery was created, incorporating a canal wall up mastoidectomy and an enlarged round window approach. Insertions were carried out using a straight electrode, a perimodiolar electrode, and a slim perimodiolar electrode, inserted through a sheath in the basal turn of the cochlea. Electrode positions were assessed after each insertion, with each type being tested 20 times.

Successful insertion rates were 95 % for the slim perimodiolar electrode, 85 % for the perimodiolar electrode, and 75 % for the slim straight electrode. Notably, the slim perimodiolar electrode required an adapted insertion technique due to the altered cochlear position in IP III cases. Statistical analysis revealed the slim perimodiolar electrode's superiority over the slim straight electrode in achieving successful insertions.

The 3D model of the IP III inner ear proved to be an effective tool for electrode testing and insertion training prior to surgery. Following multiple insertions in the 3D model, the slim perimodiolar electrode demonstrated the highest success rate, emphasizing its potential as the preferred choice for cochlear implantation in IP III cases.

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.

PubMed, Embase, and Scopus.

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.

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.

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.

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.

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.

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

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.

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.

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.

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

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.

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.

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.

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

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

Tertiary referral hospital and cochlear implant program.

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.

Cochlear implantation.

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

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.

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.

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.

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.

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.

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 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.

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

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.

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.

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.

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.

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.

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.