Real-Time Intraoperative Computed Tomography to Assist Cochlear Implant Placement in the Malformed Inner Ear

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.

Utility of Intraoperative Radiographs in Pediatric Cochlear Implant Surgery

OBJECTIVE

To evaluate the role of intraoperative radiographs to confirm electrode position following pediatric cochlear implantation (CI).

STUDY DESIGN

Retrospective chart review.

SETTING

Single tertiary care pediatric center.

METHODS

A retrospective chart review was conducted, including all pediatric patients undergoing CI at UPMC Children's Hospital of Pittsburgh over a 13-year period.

RESULTS

We identified 326 patients undergoing 492 procedures. Across the cohort, there were 7 cases that required intraoperative electrode reinsertion due to malposition or presumed malposition. For 6 of the 7 cases, intraoperative X-ray identified electrode malposition. Neural response telemetry (NRT) testing was also abnormal for 4 of these cases prior to reinsertion. Implantation of Cochlear's Slim Modiolar electrode was associated with an abnormal perioperative X-ray (odds ratio [OR]: 9.2, p = 0.03) and increased change in management (OR: 9.2, p = 0.03) compared to Cochlear's Contour Advance (CA). Incidence of abnormal X-rays was 1.24% overall, 4% in the Slim Modiolar group, and 0.3% in the CA group. The Slim Modiolar electrode accounted for 4 of 7 cases requiring reinsertion, and in all 4 of these cases, electrode fold-over was identified on the X-ray. NRT was normal in 1 of these 4 cases.

CONCLUSION

The use of Cochlear's Slim Modiolar electrode was associated with a significantly increased risk of abnormal intraoperative X-ray compared to the CA electrode. Given the risk of fold-over with routine insertion and normal electrical testing using the Slim Modiolar electrode, we recommend routine use of intraoperative skull X-ray to confirm electrode position.

Application of UNETR for automatic cochlear segmentation in temporal bone CTs

OBJECTIVE

To investigate the feasibility of a deep learning method based on a UNETR model for fully automatic segmentation of the cochlea in temporal bone CT images.

METHODS

The normal temporal bone CTs of 77 patients were used in 3D U-Net and UNETR model automatic cochlear segmentation. Tests were performed on two types of CT datasets and cochlear deformity datasets.

RESULTS

Through training the UNETR model, when batch_size=1, the Dice coefficient of the normal cochlear test set was 0.92, which was higher than that of the 3D U-Net model; on the GE 256 CT, SE-DS CT and Cochlear Deformity CT dataset tests, the Dice coefficients were 0.91, 0.93, 0 93, respectively.

CONCLUSION

According to the anatomical characteristics of the temporal bone, the use of the UNETR model can achieve fully automatic segmentation of the cochlea and obtain an accuracy close to manual segmentation. This method is feasible and has high accuracy.

Predictive Value of Transimpedance Matrix Measurements to Detect Electrode Tip Foldover

OBJECTIVE

To evaluate the ability of the transimpedance matrix (TIM) measurement to detect cochlear implant electrode tip foldover by comparing results to a "gold standard," the intraoperative plain film radiograph.

STUDY DESIGN

Retrospective case series.

SETTING

Tertiary referral hospital.

PATIENTS

One hundred three patients who underwent cochlear implantation between June 2020 and August 2021.

INTERVENTIONS

Intraoperative electrophysiologic monitoring (electrode impedances, neural response telemetry, and TIM measurement) and modified Stenver's view plain film radiographs.

MAIN OUTCOME MEASURES

Identification of tip foldover on both TIM and plain films.

RESULTS

In total, 103 patients (117 ears) had both a TIM measurement and intraoperative X-ray available for review, including 68 adults and 35 children. One hundred patients (85%) received the Cochlear Slim Modiolar electrode. Tip foldovers were noted in three of 117 implants (2.5%). In all cases, TIM was able to detect the foldover, and the electrode arrays were reinserted with the patients still under anesthesia, with repeat X-ray demonstrating a normal configuration. Two other abnormal TIM patterns were identified. One was in a patient with an obstructed cochlea in whom only 10 electrodes could be inserted, the other was in a patient with a common cavity abnormality. One additional patient underwent electrode repositioning intraoperatively because of overinsertion. In this patient, the TIM appeared to be within normal limits, but the over-insertion was apparent on X-ray. Overall, the sensitivity and specificity of TIM measurements in detecting electrode tip foldover were both 100%.

CONCLUSION

TIM measurements were able to accurately identify tip foldovers. More research is needed to define the adjunctive role of TIM as an intraoperative measure.

Comparison Between Transimpedance Matrix (TIM) Measurement and X-ray Fluoroscopy for Intraoperative Electrode Array Tip Fold-Over Detection

OBJECTIVE

The aim of this study was to compare Transimpedance Matrix (TIM-) measurement and X-ray fluoroscopy for the intraoperative detection of electrode array tip fold-over in cochlear implant recipients.

STUDY DESIGN

Retrospective agreement study.

SETTING

Tertiary referral hospital.

PATIENTS

Forty-two patients (47 ears) consecutively implanted with the Slim Modiolar Electrode.

INTERVENTIONS

Five raters, with different levels of clinical experience, individually retrospectively evaluated the TIM-heatmaps and X-ray fluoroscopy images of all patients included in this study for electrode array tip fold-over.

MAIN OUTCOME MEASURES

Agreement between raters' individual evaluation and the diagnosis given during clinical intraoperative evaluation for both modalities, as well as the inter-method agreement between TIM-measurement and fluoroscopy, and the inter-rater agreement for both modalities.

RESULTS

A tip fold-over was found in three of the forty-seven implantations (6.4%) included in this study. The average agreement between raters' evaluation and the intraoperative evaluation was 88% (Cohens κ = 0.378) for fluoroscopy and 99% (Cohens κ = 0.915) for TIM-measurement. Two raters misdiagnosed at least one tip fold-over as being correctly positioned when evaluating the fluoroscopy images (1/3 and 3/3, respectively). Each of the raters correctly detected all three tip fold-overs using the TIM-heatmaps. The inter-rater agreement for fluoroscopy was classified as "fair" (Fleiss' κ = 0.286), while the inter-rater agreement for TIM-measurement was classified as "near-perfect" (Fleiss' κ = 0.850).

CONCLUSIONS

TIM-measurement has a high potential to replace X-ray fluoroscopy for intraoperatively detecting electrode array tip fold-over in cochlear implantation, especially in patients implanted with flexible, precurved arrays.

Cochlear Implant

Cochlear implant is the first approved cranial nerve stimulator that works by directly stimulating the cochlear nerve. The medical and societal impact of this revolutionary device cannot be understated. This article reviews the evolving indications for cochlear implant, patient assessment, surgical approach, and outcomes for pediatric and adult cochlear implant that demonstrate its impact. Future concepts in cochlear implant are introduced briefly. This article covers a breadth of information; however, it is not intended be entirely comprehensive. Rather, it should serve as a foundation for understanding cochlear implant.

Extra-Cochlear Insertion in Cochlear Implantation: A Potentially Disastrous Condition

OBJECTIVES

Cochlear implantation is an increasingly used technique for auditory rehabilitation of pediatric and adult population. Safe implantation is achieved in most cases; however, intraoperative complications and misplacement of the electrode are observed in some. The aim of this presentation was to review the characteristics of patients with extra-cochlear electrode insertion, postoperative diagnostic methods, and considerations in revision surgery.

MATERIALS AND METHODS

In total, 423 cases of cochlear implantation performed in our clinic between 2012 and 2018 were retrospectively analyzed and those of extra-cochlear implantation were evaluated.

RESULTS

Extra-cochlear insertion was found in 3 patients. The electrode was placed into the internal acoustic canal in the first case, superior semicircular canal in the second case, and internal carotid artery canal in the third case. Cochlear insertion was achieved in all cases with re-implantation, and no complication was observed.

CONCLUSION

This case series highlights that rare, but potentially serious, consequences of misplacement of the electrode in cochlear implantation can be successfully avoided and treated via a multidisciplinary approach.

Auditory Brainstem Implant Array Position Varies Widely Among Adult and Pediatric Patients and Is Associated With Perception

OBJECTIVES

The auditory brainstem implant (ABI) provides sound awareness to patients who are ineligible for cochlear implantation. Auditory performance varies widely among similar ABI cohorts. We hypothesize that differences in electrode array position contribute to this variance. Herein, we classify ABI array position based on postoperative imaging and investigate the relationship between position and perception.

DESIGN

Retrospective review of pediatric and adult ABI users with postoperative computed tomography. To standardize views across subjects, true axial reformatted series of scans were created using the McRae line. Using multiplanar reconstructions, basion and electrode array tip coordinates and array angles from vertical were measured. From a lateral view, array angles (V) were classified into types I to IV, and from posterior view, array angles (T) were classified into types A to D. Array position was further categorized by measuring distance vertical from basion (D1) and lateral from midline (D2). Differences between array classifications were compared with audiometric thresholds, number of active electrodes, and pitch ranking.

RESULTS

Pediatric (n = 4, 2 with revisions) and adult (n = 7) ABI subjects were included in this study. Subjects had a wide variety of ABI array angles, but most were aimed superiorly and posteriorly (type II, n = 7) from lateral view and upright or medially tilted from posterior view (type A, n = 6). Mean pediatric distances were 8 to 42% smaller than adults for D1 and D2. In subjects with perceptual data, electrical thresholds and the number of active electrodes differed among classification types.

CONCLUSIONS

In this first study to classify ABI electrode array orientation, array position varied widely. This variability may explain differences in auditory performance.

Intra-cochlear electrode tip fold-over

Cochlear implantation has been performed safely for over two decades but still has various minor and major complications. We report two cases of an unusual complication of electrode implantation: tip fold-over of the electrode array within the cochlea. Both cases required undergoing explantation and re-implantation. The frequent use of fine and pre-curved electrodes particularly with the use of an insertion tool necessitates routine postoperative radiological evaluation of the electrode array. Our cases demonstrate the benefit of systematic imaging including the possible use of the Cone Beam CT intraoperatively.

Utility of intraoperative computed tomography for cochlear implantation in patients with difficult anatomy

OBJECTIVE AND IMPORTANCE

To describe cases that illustrate the utility of intraoperative computed tomography (CT) in cochlear implantation of patients with difficult temporal bone anatomy.

CLINICAL PRESENTATION

A 2-year-old male with congenital X-linked stapes gusher syndrome and a 2-year-old female with enlarged vestibular aqueduct underwent successful cochlear implantation with the help of intraoperative CT. In the latter case, the initial intraoperative C-arm fluoroscopy suggested malposition of the electrode, however, was not able to provide details for adjustments. In both cases, intraoperative CT changed the insertion technique of the operating surgeon and allowed for improved electrode positioning. A 47-year-old female with polyostotic fibrous dysplasia and a 55-year-old male with post-meningitis near-total cochlear obliteration underwent successful cochlear implantation with confirmation of electrode position with intraoperative CT. In the former case, the image-guided navigation system was also implemented. Finally, a 72-year-old female underwent cochlear implantation during which intraoperative C-arm fluoroscopy suggested intra-cochlear insertion. However, postoperative CT showed the electrode extending into the internal auditory canal (IAC), illustrating the limitations of C-arm fluoroscopy.

INTERVENTION

Intraoperative CT imaging and image-guided navigation system.

CONCLUSION

When faced with challenging temporal bone anatomy, intraoperative CT can provide critical details of the patient's microanatomy that allows for improved localization of the electrode and adjustments in operative techniques for successful cochlear implantation.

Slotted labyrinthotomy approach with customized electrode for patients with common cavity deformity

OBJECTIVES/HYPOTHESIS

Cochlear implantation for patients with common cavity deformity (CCD) can be difficult, with a higher incidence of intra- and postoperative complications; outcomes with CCD patients are also highly variable. In this study, surgical time was compared between the traditional facial recess approach (TFRA) and the transmastoid slotted labyrinthotomy approach (TSLA). Audiological outcomes and the benefit of using customized electrode arrays for CCD patients are also discussed.

STUDY DESIGN

Retrospective review of 13 cochlear implant (CI) patients with CCD.

METHODS

Six patients were implanted with the TFRA using traditional electrodes, and seven patients were implanted with the TSLA using customized electrodes. Intra- and postoperative complications were reviewed. Audiological outcomes were measured 3 months to 2 years after CI activation.

RESULTS

The mean surgical time for TSLA group was nearly half as long as for the TRFA group (P < .05). Although mean audiological outcomes were better for the TSLA group, there was no significant difference between groups (P > .05).

CONCLUSIONS

For CCD patients, TSLA for cochlear implantation is recommended due to shortened surgical time; customized electrode arrays may be additionally advantageous in terms of audiological outcomes.

LEVEL OF EVIDENCE

4. Laryngoscope, 128:468-472, 2018.

Long term outcome of cochlear implantation in five children with common cavity deformity

INTRODUCTION

A common cavity (CC) deformity is a deformed inner ear in which the cochlea and vestibule are confluent forming a common rudimentary cystic cavity. The outcome of cochlear implantation (CI) in this deformity is not expected as good as in other cochlear deformity. Categories of Auditory Performance (CAP) score, Speech Intelligibility Rating (SIR) scale, Meaningful Auditory-Integration Scale (MAIS) and Meaningful Use of Speech Scale (MUSS) are scales designed to assess benefit of functional device (hearing aid, Cochlear implant, ABI) in young children. The aim of the study was to observe and report the long-term audiological progress and speech development of children with CC deformity after CI by means of CAP, SIR, MAIS, MUSS scores and CI aided threshold.

METHODS AND MATERIALS

The retrospective and prospective study was carried out in five Indian children with CC deformity who underwent CI from 2004 to 2010. Demographic data of onset and/or duration of deafness, age at implantation, time with hearing aids before implantation, duration with CI and co-morbidity were retrieved from a local data base. Their outcome score in audition and speech development on the basis of their CAP and SIR score at the end of 1 year of habilitation were collected. All the patients were called to follow up to obtain latest CI aided audiogram, CAP, SIR, MAIS and MUSS scores.

RESULTS

One male and four female children were detected with common cavity deformity among 258 deaf children of age below 6 years operated during study period. The CAP and SIR Scores increased from average of 0.4 and 1 to 3.4 and 2.4, respectively, over one year of habilitation. The CAP score improved in subsequent follow up to average of 5.0 after more than 3 years of follow up but the SIR score hardly improved. We assessed the MAIS and MUSS at last visit after 3 years. The mean of MAIS and MUSS was 32.4 and 26.4, respectively.

CONCLUSION

Though the habilitation outcome was not up to the mark in children with CC deformity, CI provides excellent awareness of environment sound and development of few words.

Revision cochlear implantation following internal auditory canal insertion

OBJECTIVES/HYPOTHESIS

In pediatric patients with congenital malformations of the inner ear, anomalies within the anatomy may facilitate unintentional insertion of the cochlear implant electrode into the internal auditory canal. Revision procedures for removal and replacement of cochlear implant electrodes following internal auditory canal insertion are fraught with potential danger, including the theoretical risk of injury to vasculature within the internal auditory canal, repeat insertion within the internal auditory canal, and cerebrospinal fluid leak. The objective of this presentation is to describe a technique for revision cochlear implantation following internal auditory canal insertion to minimize the potential associated risks.

STUDY DESIGN

Case series.

METHODS

A retrospective chart review was performed on all patients at a tertiary care facility who underwent revision cochlear implantation for internal auditory canal insertion between January 1999 and July 2011.

RESULTS

A total of four patients referred from outside institutions have undergone revision cochlear implantation for internal auditory canal insertion. The records from these patients were reviewed. Electrodes were safely removed in all cases without injury to the anterior inferior cerebellar artery or its branches (i.e., labyrinthine artery). Complete insertion was accomplished on reimplantation. Neural response telemetry was performed in all cases, and responses were noted. Fluoroscopy was utilized to visualize electrode progression during insertion. A detailed description of the operative technique is provided.

CONCLUSIONS

This case series describes a technique for revision cochlear implantation that appears to be safe and effective in preventing potential associated complications.

Comparison of Intraoperative Portable CT Scanners in Skull Base and Endoscopic Sinus Surgery: Single Center Case Series

Precise and safe management of complex skull base lesions can be enhanced by intraoperative computed tomography (CT) scanning. Surgery in these areas requires real-time feedback of anatomic landmarks. Several portable CT scanners are currently available. We present a comparison of our clinical experience with three portable scanners in skull base and craniofacial surgery. We present clinical case series and the participants were from the Northwestern Memorial Hospital. Three scanners are studied: one conventional multidetector CT (MDCT), two digital flat panel cone-beam CT (CBCT) devices. Technical considerations, ease of use, image characteristics, and integration with image guidance are presented for each device. All three scanners provide good quality images. Intraoperative scanning can be used to update the image guidance system in real time. The conventional MDCT is unique in its ability to resolve soft tissue. The flat panel CBCT scanners generally emit lower levels of radiation and have less metal artifact effect. In this series, intraoperative CT scanning was technically feasible and deemed useful in surgical decision-making in 75% of patients. Intraoperative portable CT scanning has significant utility in complex skull base surgery. This technology informs the surgeon of the precise extent of dissection and updates intraoperative stereotactic navigation.

An evidence-based algorithm for intraoperative monitoring during cochlear implantation

OBJECTIVE

To generate an evidence-based algorithm for the use of intraoperative testing during cochlear implantation (CI).

STUDY DESIGN

Retrospective review.

SETTING

Tertiary referral center.

PATIENTS

A total of 277 children (aged 6 mo to 17 yr) and adults 18 years and older with normal cochlear anatomy who underwent primary and revision cochlear implantation at a single center between 2005 and 2010 were included.

INTERVENTION

Intraoperative electrophysiologic monitoring and intraoperative Stenver's view plain film radiography.

MAIN OUTCOME MEASURE

Intraoperative testing included the following: 1) individual electrode impedance measurements; 2) neural response telemetry (tNRT) levels for electrodes E20, E15, E10, and E5; and 3) plain film radiograph assessment of electrode position.

RESULTS

No patient demonstrated abnormalities on all 3 modalities. Open or short electrodes on impedance testing were found in 6% of patients; half of these normalized when remeasured. Absent tNRT responses on 1 or more electrodes occurred in 14% of patients, although complete lack of response was rare (1.4%) and did not correlate with a dysfunctional device. Spread of excitation was performed in 1 patient and was consistent with a tip rollover. Intraoperative radiography identified tip-rollover and extracochlear electrode placement in all cases (n = 5, 1.8%) and prompted the use of the backup device.

CONCLUSION

Immediate intraoperative determination of device functionality and optimal electrode placement is advantageous. Of the modalities tested, including electrode impedance, tNRT, and plain radiograph, only the radiographic results impacted intraoperative surgical decision making and led to the use of the backup device.

Cochlear Implantation in Children with Anomalous Cochleovestibular Anatomy

Objective. To determine the influence of inner ear dysplasia on both surgical and audiologic outcomes following pediatric cochlear implant (CI) surgery.

Data Sources. MEDLINE (1982-2009) and data from Massachusetts Eye and Ear Infirmary.

Review Methods. A systematic review of the literature was performed. Variables assessed included age at implantation, duration of CI use, radiologic and operative findings, and speech perception outcome data.

Results. The initial search yielded 1326 articles. Including data from our own study, twenty-two fulfilled criteria for inclusion, representing 311 patients. Data for bilateral implants were recorded only for the first implant. Data on simultaneous bilateral implants were not recorded. The most common anomaly seen was large vestibular aqueduct (89/311 or 29%). When comparing patients with mild-moderate or severe dysplasia, rates of cerebrospinal fluid gusher were 31% versus 35% (odds ratio [OR] = 0.50), anomalous facial nerve anatomy was seen in 11% versus 51% (OR = 0.15), and postoperative speech perception abilities were found in 84% versus 54% (OR = 1.93), respectively. A large heterogeneity was found among studies regarding all outcome measures.

Conclusion. Although we found that severe inner ear dysplasia was associated with increased surgical difficulty and lower speech perception, the lack of uniformity in published clinical data limited the strength of these results. Standardization of surgical and radiologic reporting as well as more consistent speech perception testing is needed to better determine the association between anomalous cochleovestibular anatomy and clinical outcomes.

A practical, single-view alternative to Stenver's for plain radiographic unilateral and bilateral post-cochlear implant position check

INTRODUCTION

'Stenver's' is the standard plain radiograph view to check the electrode position after cochlear implantation. However, a reproducible alignment for intra-individual comparison of electrode position using a true Stenver's alignment is not always straightforward to achieve, particularly for inexperienced radiographers, or on non-compliant children. In addition, two ionizing exposures in two different positions are required for bilateral cochlear implants.

AIMS

To assess the efficacy of other, more simple, single-exposure radiographs for the assessment of electrode position.

METHODS

Dummy electrodes and receiver units were bilaterally implanted into a cadaver. Plain radiographs in Stenver's views, and plain antero-posterior (AP) midline radiographic single views incorporating both implants were obtained with the tube at a range of angles tilted caudal and cranial to the perpendicular. Five internationally renowned cochlear implant surgeons were each asked if each radiograph gave adequate information for unilateral and for bilateral implants and they were asked to list in order of their favoured top three views.

RESULTS

No surgeon thought that a single-exposure Stenver's view was adequate for assessment of the contra-lateral side. Consensus was that all AP views were fit for the purpose, with no preference given between each of the AP views. The ipsi-lateral Stenver's was considered to give better depth of insertion information.

CONCLUSION

There is no apparent advantage of caudal and cranial tilt angles over a straight perpendicular AP. A single-view AP radiograph is an alternative to Stenver's view for a post-unilateral and post-simultaneous bilateral cochlear implant check.

Spectrum of hearing disorders and their management in children with CHARGE syndrome

OBJECTIVE

The CHARGE syndrome is associated with ear anomalies and deafness in addition to other malformations. Deformations of the ossicles or aplasia of the semicircular canals, cochlear hypoplasia, hypoplasia or aplasia of the VIIIth cranial nerve and abnormal routing of the VIIth cranial nerve, sigmoid sinus, and emissaries are typical findings. The aim of this study is to explore the feasibility and procedure of cochlear implantation in patients with CHARGE syndrome and to assess the outcome.

STUDY DESIGN

Retrospective case review.

SETTING

Tertiary referral center; cochlear implant program.

PATIENTS

Ten patients with CHARGE syndrome and 3 patients with CHARGE-like syndrome treated in our center due to hearing impairment. Eleven patients were congenitally deaf, 1 patient had progressive hearing loss, and 1 patient had mixed hearing loss.

INTERVENTION

Computed tomography of temporal bones and magnetic resonance imaging of the brain; bone-anchored hearing aid surgery, cochlear implantation, rehabilitation results.

MAIN OUTCOME MEASURES

Surgical suitability and hearing rehabilitation.

RESULTS

We illustrate the management of preoperative diagnostics, surgical planning, and hearing rehabilitation. One patient with mixed hearing loss underwent bilateral bone-anchored hearing aid surgery. Because 2 patients had bilateral aplasia of the auditory nerves, we recommended an auditory brainstem implant. The unilateral cochlear implantation was performed in 9 patients and bilateral in 1 patient. In selected cases, it was helpful to plan the operation using a simulator for temporal bone surgery. Complex malformations, such as in CHARGE syndrome, with an increased intraoperative risk for complications should be facilitated by using intraoperative digital volume tomography-assisted navigation and intraoperative digital volume tomography control of electrode position. The results after CI surgery vary due to the differing extent of additional disabilities such as developmental delay, intellectual delay, and visual impairment. Nine of our patients showed improved responsiveness with the cochlear implant. Open speech comprehension could not be observed in 8 patients, whereas the follow-up period was less than 1 year in 4 patients. The relatively high age of our patients at implantation might be an important factor.

CONCLUSION

Careful planning of the treatment of CHARGE syndrome patients with sensorineural hearing loss can, to a limited extent, lead to auditory benefit without increasing surgical complications. Cochlear implantation is therefore indicated after critical assessment.

[Surgical technique in cochlear implantation]

The cochlear implant (CI) has become a standard option for treating prelingually deaf children. But postlingual late deafness in adults is becoming increasingly common. In addition, hybrid implantation with a CI and a hearing aid in the same ear has come into focus, which demands a soft insertion technique that spares the apical parts of the cochlea. Also, the chorda tympani should be saved, especially in bilateral implantations, which are gaining importance because improved speech discrimination in noisy conditions is seen as proven today. Control of the electrode position intraoperatively with intraoperative computed tomography can further increase the safety and reliability of the position. The position and length of the skin incision is a more aesthetic issue. Future developments will include fully implantable CIs and navigation-assisted, minimally invasive drilling of a hole from the surface of the skull into the cochlea. Bioactive, neurotrophic-drug-releasing electrode designs for improved and sustainable connectivity to the neurons may become applicable.