Outcomes of cochlear implantation in Usher syndrome: a systematic review.

PURPOSE: This study is a systematic review of the literature which seeks to evaluate auditory and quality of life (QOL) outcomes of cochlear implantation in patients with Usher syndrome. METHODS: Systematic review of studies indexed in Medline via PubMed, Ovid EMBASE, Web of Science, CENTRAL and clinicaltrials.gov was performed up to March 9th 2022, conducted in accordance with the PRISMA statement. Patient demographics, comorbidity, details of cochlear implantation, auditory, and QOL outcomes were extracted and summarized. RESULTS: 33 studies reported over 217 cochlear implants in 187 patients with Usher syndrome, comprising subtypes 1 (56 patients), 2 (9 patients), 3 (23 patients), and not specified (99 patients). Auditory outcomes included improved sound detection, speech perception, and speech intelligibility. QOL outcomes were reported for 75 patients, with benefit reported in the majority. CONCLUSIONS: Many patients with Usher syndrome develop improved auditory outcomes after cochlear implantation with early implantation being an important factor.

Frequency of electrode migration after cochlear implantation in the early postoperative period. What are associated risk factors?

OBJECTIVES: To estimate the prevalence of, and risk factors associated with electrode migration (EM) in cochlear implant (CI) recipients. DESIGN: Historical cohort study of all CIs performed between 1 January 2018 and 1 August 2021 in a single tertiary adult and paediatric CI centre in the UK. MAIN OUTCOME MEASURES: The primary aim is to determine the prevalence of electrode migration, comparing intraoperative surgeon report and examination of a routine plain radiograph performed 2 weeks after surgery. EM is defined as the detection of movement of two or more electrodes out of the cochlea from the time of surgery. Multivariate analysis was performed to investigate preoperative and intraoperative risk factors that might predispose to migration. RESULTS: Four hundred and sixty-five patients, having 516 distinct surgeries, with 628 implants were analysed. EM occurred following 11.5% of implant operations. Pre-existing cochlear abnormality was an independent associated risk factor for EM (OR: 3.40 ⟨1.20-9.62⟩ p = .021). Demographics, surgical technique, usage of a precurved electrode, CSF leak, surgeon seniority and intraoperative telemetry did not influence risk of migration. There were 5 implants (0.8%) which migrated later than 2 weeks, with a median date of imaging diagnosis (x-ray or CT scan) of 263 days ⟨IQR:198⟩, for which head injury was a common precipitating factor. There were differences in the risk of migration between different lateral wall electrodes. CONCLUSION: EM in the early postoperative period is a common occurrence and is more likely in implant recipients with obstructed or malformed cochleae.

Detecting and managing partial shorts in Cochlear implants: A validation of scalp surface potential testing.

OBJECTIVE: To investigate the value of scalp surface potentials to identify and manage partial short circuits to ground in cochlear implant electrodes. DESIGN: A retrospective review of patients with suspected partial short circuits. MAIN OUTCOME MEASURE: Electrical output of individual electrodes was measured using scalp surface potentials for patients reporting a change in hearing function. Electrical output was compared to functional performance and impedance measurements to determine if devices with suspected partial short circuits were experiencing a decrease in performance as a result of reduced electrical output. Electrical output was checked in an artificial cochlea for two implants following explant surgery to confirm scalp surface potential results. RESULTS: All patients with suspected partial short circuits (n = 49) had reduced electrical output, a drop in impedances to approximately ½ of previously stable measurements or to below 2 kΩ, an atypical electrical field measurement (EFI) and a decline in hearing function. Only devices with an atypical EFI showed reduced electrical output. Results of scalp based surface potentials could be replicated in an artificial cochlea following explantation of the device. All explant reports received to date (n = 42) have confirmed partial short circuits, with an additional four devices failing integrity tests. CONCLUSION: Surface potential measurements can detect partial shorts and had 100% correlation with atypical EFI measurements, which are characteristic of a partial short to ground in this device. Surface potentials can help determine the degree to which the electrode array is affected, particularly when behavioural testing is limited or not possible.

Detection of Extracochlear Electrodes in Cochlear Implants with Electric Field Imaging/Transimpedance Measurements: A Human Cadaver Study.

OBJECTIVES: Extracochlear electrodes in cochlear implants (CI), defined as individual electrodes on the electrode array located outside of the cochlea, are not a rare phenomenon. The presence of extracochlear electrodes frequently goes unnoticed and could result in them being assigned stimulation frequencies that are either not delivered to, or stimulating neurons that overlap with intracochlear electrodes, potentially reducing performance. The current gold-standard for detection of extracochlear electrodes is computed tomography (CT), which is time-intensive, costly and involves radiation. It is hypothesized that a collection of Stimulation-Current-Induced Non-Stimulating Electrode Voltage recordings (SCINSEVs), commonly referred to as "transimpedance measurements (TIMs)" or electric field imaging (EFI), could be utilized to detect extracochlear electrodes even when contact impedances are low. An automated analysis tool is introduced for detection and quantification of extracochlear electrodes. DESIGN: Eight fresh-frozen human cadaveric heads were implanted with the Advanced Bionics HiRes90K with a HiFocus 1J lateral-wall electrode. The cochlea was flushed with 1.0% saline through the lateral semicircular canal. Contact impedances and SCINSEVs were recorded for complete insertion and for 1 to 5 extracochlear electrodes. Measured conditions included: air in the middle ear (to simulate electrodes situated in the middle ear), 1.0% saline in the middle ear (to simulate intraoperative conditions with saline or blood in the middle ear), and soft tissue (temporal muscle) wrapped around the extracochlear electrodes (to simulate postoperative soft-tissue encapsulation of the electrodes). Intraoperative SCINSEVs from patients were collected, for clinical purposes during slow insertion of the electrode array, as well as from a patient postoperatively with known extracochlear electrodes. RESULTS: Full insertion of the cochlear implant in the fresh-frozen human cadaveric heads with a flushed cochlea resulted in contact impedances in the range of 6.06 ± 2.99 kΩ (mean ± 2SD). Contact impedances were high when the extracochlear electrodes were located in air, but remained similar to intracochlear contact impedances when in saline or soft tissue. SCINSEVs showed a change in shape for the extracochlear electrodes in air, saline, and soft tissue. The automated analysis tool showed a specificity and sensitivity of 100% for detection of two or more extracochlear electrodes in saline and soft tissue. The quantification of two or more extracochlear electrodes was correct for 84% and 81% of the saline and soft tissue measurements, respectively. CONCLUSIONS: Our analysis of SCINSEVs (specifically the EFIs from this manufacturer) shows good potential as a detection tool for extracochlear electrodes, even when contact impedances remain similar to intracochlear values. SCINSEVs could potentially replace CT in the initial screening for extracochlear electrodes. Detecting migration of the electrode array during the final stages of surgery could potentially prevent re-insertion surgery for some CI users. The automated detection tool could assist in detection and quantification of two or more extracochlear electrodes.

A systematic review on prevention and management of wound infections from cochlear implantation.

OBJECTIVE OF REVIEW: Surgical site infections are a recognised complication of cochlear implant (CI) surgery with significant morbidity. Our aim was to search for the optimum prevention and management strategy to deal with this issue. TYPE OF REVIEW: Systematic review. SEARCH STRATEGY: A systematic literature search was undertaken from the databases of Embase, CINAHL, MEDLINE® , Web of Science, Scopus and Cochrane Library according to the predefined inclusion and exclusion criteria. EVALUATION METHOD: All relevant titles, abstracts and full-text articles were reviewed by two authors who resolved any differences by discussion and consultation with senior authors. RESULTS: Fourteen articles were included in our review. The overall quality of evidence was low with the vast majority of the studies being retrospective case series and expert opinions. No randomised controlled trials were noted. We found consistent reports that intraoperative prophylactic antibiotics should be given to all patients undergoing CI and that the vast majority of CI wound infections had grown Staphylococcal spp. or Pseudomonas spp. CONCLUSION: Our review has not identified any reliable or reproducible strategies to prevent and deal with wound infections after CI. We strongly encourage further research within this field and would suggest that a consensus of opinions from a multidisciplinary panel of experts may be a pragmatic way forward as an effective guide.

Hearing loss.

Hearing loss affects one in six people in the UK and is a significant disease burden. In addition to communication problems, there is also an association with depression and dementia. Clinical assessment with targeted history and examination can identify the characteristics and cause of hearing loss, and complementary audiological testing can confirm its type and severity. Retrocochlear screening is recommended for sudden, rapidly progressive or asymmetric sensorineural hearing loss. Medical or surgical therapies may be indicated in cases of conductive hearing loss, while hearing assistive devices and hearing aids are the mainstay of rehabilitation for sensorineural hearing loss.

In vivo measurement of basilar membrane vibration in the unopened chinchilla cochlea using high frequency ultrasound.

The basilar membrane and organ of Corti in the cochlea are essential for sound detection and frequency discrimination in normal hearing. There are currently no methods used for real-time high resolution clinical imaging or vibrometry of these structures. The ability to perform such imaging could aid in the diagnosis of some pathologies and advance understanding of the causes. It is demonstrated that high frequency ultrasound can be used to measure basilar membrane vibrations through the round window of chinchilla cochleas in vivo. The basic vibration characteristics of the basilar membrane agree with previous studies that used other methods, although as expected, the sensitivity of ultrasound was not as high as optical methods. At the best frequency for the recording location, the average vibration velocity amplitude was about 4 mm/s/Pa with stimulus intensity of 50 dB sound pressure level. The displacement noise floor was about 0.4 nm with 256 trial averages (5.12 ms per trial). Although vibration signals were observed, which likely originated from the organ of Corti, the spatial resolution was not adequate to resolve any of the sub-structures. Improvements to the ultrasound probe design may improve resolution and allow the responses of these different structures to be better discriminated.

Wideband acoustic immittance measurements in assessing crimping status following stapedotomy: A temporal bone study.

OBJECTIVE: To ascertain if wideband acoustic immitance (WAI) measurements are useful in assessing crimping status following stapedotomy. DESIGN: WAI measurements were obtained using the Mimosa Acoustics HearID system. Wideband chirp sound stimuli and a set of tone stimuli for nine frequencies between 0.2 and 6 kHz were used at 60 dB SPL. Five sets of measurements were performed on each temporal bone: mobile stapes, stapes fixation and stapedotomy followed by insertion of a tightly crimped, a loosely crimped and an uncrimped prosthesis. STUDY SAMPLE: Eight fresh-frozen temporal bones were harvested from human cadaveric donors. RESULTS: At lower frequencies, up to 1 kHz, stapes fixation decreased absorbance. Compared to the baseline absorbance, absorbance with stapes fixation dropped by 6 to 17% in absolute terms from the baseline value (p = 0.027). Absorbance was not affected in higher frequencies (p = 0.725). Stapedotomy changed the absorbance curve significantly compared to the normal condition with an increase of absolute absorbance values by 6 to 36% around 0.25-1 kHz (p-value <0.01). The crimping conditions did not differ from one another (p = 0.555). CONCLUSION: WAI is not useful in distinguishing between tightly crimped, loosely crimped and uncrimped stapes prostheses following stapedotomy.

A scoping review on the clinical effectiveness of Trans-Impedance Matrix (TIM) measurements in detecting extracochlear electrodes and tip fold overs in Cochlear Ltd devices.

BACKGROUND: Extrusion of electrodes outside the cochlea and tip fold overs may lead to suboptimal outcomes in cochlear implant (CI) recipients. Intraoperative measures such as Trans-Impedance Matrix (TIM) measurements may enable clinicians to identify electrode malposition and direct surgeons to correctly place the electrode array during surgery. OBJECTIVES: To assess the current literature on the effectiveness of TIM measurements in identifying extracochlear electrodes and tip fold overs. METHODS: A scoping review of studies on TIM-based measurements were carried out using the Databases-Medline/PubMed, AMED, EMBASE, CINAHL and the Cochrane Library following PRISMA guidelines. Eleven full texts articles met the inclusion criteria. Only human studies pertaining to TIM as a tool used in CI were included in the review. Further, patient characteristics, electrode design, and TIM measurement outcomes were reported. RESULTS: TIM measurements were available for 550 implanted ears with the subjects age ranged between 9 months to 89 years. Abnormal TIM measurements were reported for 6.55% (36). Tip fold over was detected in 3.64% (20) of the cases, extracochlear electrodes in 1.45% (8), and 1.45% (8) were reported as buckling. Slim-modiolar electrode array designs were more common (54.71%) than pre-curved (23.34%) or lateral wall (21.95%) electrode array. Abnormal cochlear anatomy was reported for five ears (0.89%), with normal cochlear anatomy for all other patients. CONCLUSION: TIM measurement is a promising tool for the intraoperative detection of electrode malposition. TIM measurement has a potential to replace intraoperative imaging in future. Though, TIM measurement is in its early stages of clinical utility, intuitive normative data sets coupled with standardised criteria for detection of abnormal electrode positioning would enhance its sensitivity.

Protocol for a multicentre randomised controlled trial of STeroid Administration Routes For Idiopathic Sudden sensorineural Hearing loss: The STARFISH trial.

Idiopathic sudden sensorineural hearing loss (ISSNHL) is the rapid onset of reduced hearing due to loss of function of the inner ear or hearing nerve of unknown aetiology. Evidence supports improved hearing recovery with early steroid treatment, via oral, intravenous, intratympanic or a combination of routes. The STARFISH trial aims to identify the most clinically and cost-effective route of administration of steroids as first-line treatment for ISSNHL. STARFISH is a pragmatic, multicentre, assessor-blinded, three-arm intervention, superiority randomised controlled trial (1:1:1) with an internal pilot (ISRCTN10535105, IRAS 1004878). 525 participants with ISSNHL will be recruited from approximately 75 UK Ear, Nose and Throat units. STARFISH will recruit adults with sensorineural hearing loss averaging 30dBHL or greater across three contiguous frequencies (confirmed via pure tone audiogram), with onset over a ≤3-day period, within four weeks of randomisation. Participants will be randomised to 1) oral prednisolone 1mg/Kg/day up to 60mg/day for 7 days; 2) intratympanic dexamethasone: three intratympanic injections 3.3mg/ml or 3.8mg/ml spaced 7±2 days apart; or 3) combined oral and intratympanic steroids. The primary outcome will be absolute improvement in pure tone audiogram average at 12-weeks following randomisation (0.5, 1.0, 2.0 and 4.0kHz). Secondary outcomes at 6 and 12 weeks will include: Speech, Spatial and Qualities of hearing scale, high frequency pure tone average thresholds (4.0, 6.0 and 8.0kHz), Arthur Boothroyd speech test, Vestibular Rehabilitation Benefit Questionnaire, Tinnitus Functional Index, adverse events and optional weekly online speech and pure tone hearing tests. A health economic assessment will be performed, and presented in terms of incremental cost effectiveness ratios, and cost per quality-adjusted life-year. Primary analyses will be by intention-to-treat. Oral prednisolone will be the reference. For the primary outcome, the difference between group means and 97.5% confidence intervals at each time-point will be estimated via a repeated measures mixed-effects linear regression model.

A Multicenter Comparison of 1-yr Functional Outcomes and Programming Differences Between the Advanced Bionics Mid-Scala and SlimJ Electrode Arrays.

OBJECTIVE: To determine if there is a difference in hearing outcomes or stimulation levels between Advanced Bionics straight and precurved arrays. STUDY DESIGN: Retrospective chart review across three implant centers. SETTING: Tertiary centers for cochlear and auditory brainstem implantation. PATIENTS: One hundred fifteen pediatric and 205 adult cochlear implants (CIs) were reviewed. All patients were implanted under the National Institute for Health and Care Excellence 2009 guidelines with a HiRes Ultra SlimJ or Mid-Scala electrode array. MAIN OUTCOME MEASURES: Hearing preservation after implantation, as well as CI-only listening scores for Bamford-Kowal-Bench sentences were compared 1 year after implantation. Stimulation levels for threshold and comfort levels were also compared 1 year after implantation. RESULTS: Hearing preservation was significantly better with the SlimJ compared with the Mid-Scala electrode array. Bamford-Kowal-Bench outcomes were not significantly different between the two arrays in any listening condition. Stimulation levels were not different between arrays but did vary across electrode contacts. At least one electrode was deactivated in 33% of implants but was more common for the SlimJ device. CONCLUSION: Modern straight and precurved arrays from Advanced Bionics did not differ in hearing performance or current requirements. Although hearing preservation was possible with both devices, the SlimJ array would still be the preferred electrode in cases where hearing preservation was a priority. Unfortunately, the SlimJ device was also prone to poor sound perception on basal electrodes. Further investigation is needed to determine if deactivated electrodes are associated with electrode position/migration, and if programming changes are needed to optimize the use of these high-frequency channels.

Impact of Scala Tympani Geometry on Insertion Forces during Implantation.

(1) Background: During a cochlear implant insertion, the mechanical trauma can cause residual hearing loss in up to half of implantations. The forces on the cochlea during the insertion can lead to this mechanical trauma but can be highly variable between subjects which is thought to be due to differing anatomy, namely of the scala tympani. This study presents a systematic investigation of the influence of different geometrical parameters of the scala tympani on the cochlear implant insertion force. The influence of these parameters on the insertion forces were determined by testing the forces within 3D-printed, optically transparent models of the scala tympani with geometric alterations. (2) Methods: Three-dimensional segmentations of the cochlea were characterised using a custom MATLAB script which parametrised the scala tympani model, procedurally altered the key shape parameters (e.g., the volume, vertical trajectory, curvature, and cross-sectional area), and generated 3D printable models that were printed using a digital light processing 3D printer. The printed models were then attached to a custom insertion setup that measured the insertion forces on the cochlear implant and the scala tympani model during a controlled robotic insertion. (3) Results: It was determined that the insertion force is largely unaffected by the overall size, curvature, vertical trajectory, and cross-sectional area once the forces were normalised to an angular insertion depth. A Capstan-based model of the CI insertion forces was developed and matched well to the data acquired. (4) Conclusion: By using accurate 3D-printed models of the scala tympani with geometrical alterations, it was possible to demonstrate the insensitivity of the insertion forces to the size and shape of the scala tympani, after controlling for the angular insertion depth. This supports the Capstan model of the cochlear implant insertion force which predicts an exponential growth of the frictional force with an angular insertion depth. This concludes that the angular insertion depth, rather than the length of the CI inserted, should be the major consideration when evaluating the insertion force and associated mechanical trauma caused by cochlear implant insertion.

Management of Severe Facial Nerve Cross Stimulation by Cochlear Implant Replacement to Change Pulse Shape and Grounding Configuration: A Case-series.

OBJECTIVES: To investigate the combined effect of changing pulse shape and grounding configuration to manage facial nerve stimulation (FNS) in cochlear implant (CI) recipients. PATIENTS: Three adult CI recipients with severe FNS were offered a replacement implant when standard stimulation strategies and programming adjustments did not resolve symptoms. Our hypothesis was that the facial nerve was less likely to be activated when using anodic pulses with "mixed-mode" intra-cochlear and extra-cochlear current return. INTERVENTION: All patients were reimplanted with an implant that uses a pseudo-monophasic anodic pulse shape, with mixed-mode grounding (stimulus mixed-mode anodic)-the Neuro Zti CI (Oticon Medical). This device also allows measurements of neural function and loudness with monopolar, symmetric biphasic pulses (stimulus MB), the clinical standard used by most CIs as a comparison. MAIN OUTCOME MEASURES: The combined effect of pulse shape and grounding configuration on FNS was monitored during surgery. Following CI activation, FNS symptoms and performance with the Neuro Zti implant were compared with outcomes before reimplantation. RESULTS: FNS could only be recorded using stimulus MB for all patients. In clinical use, all patients reported reduced FNS and showed an improvement in Bamford-Kowal-Bench sentences recognition compared with immediately before reimplantation. Bamford-Kowal-Bench scores with a male speaker were lower compared with measurements taken before the onset of severe FNS for patients 1 and 2. CONCLUSIONS: In patients where CI auditory performance was severely limited by FNS, charge-balanced pseudo-monophasic stimulation mode with a mixed-mode grounding configuration limited FNS and improved loudness percept compared with standard biphasic stimulation with monopolar grounding.

Practicable assessment of cochlear size and shape from clinical CT images.

There is considerable interpersonal variation in the size and shape of the human cochlea, with evident consequences for cochlear implantation. The ability to characterize a specific cochlea, from preoperative computed tomography (CT) images, would allow the clinician to personalize the choice of electrode, surgical approach and postoperative programming. In this study, we present a fast, practicable and freely available method for estimating cochlear size and shape from clinical CT. The approach taken is to fit a template surface to the CT data, using either a statistical shape model or a locally affine deformation (LAD). After fitting, we measure cochlear size, duct length and a novel measure of basal turn non-planarity, which we suggest might correlate with the risk of insertion trauma. Gold-standard measurements from a convenience sample of 18 micro-CT scans are compared with the same quantities estimated from low-resolution, noisy, pseudo-clinical data synthesized from the same micro-CT scans. The best results were obtained using the LAD method, with an expected error of 8-17% of the gold-standard sample range for non-planarity, cochlear size and duct length.

Cochlear Implantation in NF2 Patients Without Intracochlear Schwannoma Removal.

OBJECTIVE: To determine if cochlear implantation without removal of inner ear schwannomas (IES) is an effective treatment option for Neurofibromatosis 2 (NF2) patients. To determine how the presence of an intracochlear schwannoma might impact cochlear implant (CI) outcomes and programming parameters. STUDY DESIGN: Retrospective chart review. SETTING: Tertiary center for cochlear and auditory brainstem implantation. PATIENTS: Of 10 NF2 patients with IES, 8 are reported with no previous tumor removal on the implanted ear. INTERVENTIONS: Cochlear implant without tumor removal. MAIN OUTCOME MEASURES: Performance outcomes with CI at least 1-year post intervention. Programming parameters, including impedances, for patients with IES. RESULTS: All patients had full insertion of the electrode arrays with round window approaches. Performance outcomes ranged from 0 to 100% for Bamford-Kowal-Bench sentences. Impedance measurements for active electrodes for patients with IES were comparable to those measured in patients without vestibular schwannoma (VS). Only patients who had radiation treatment before receiving their implant had elevated threshold requirements for CI programming compared with CI recipients without VS. CONCLUSION: Cochlear implantation without tumor removal is an effective option for treating NF2 patients with IES. The presence of an intracochlear tumor did not have an impact on CI performance or programming requirements compared with patients without VS; however, previous treatment with radiation may be related to elevated current requirements in the CI settings.

Cochlear Implant Infections and Outcomes: Experience From a Single Large Center.

OBJECTIVE: To review our experience with cochlear implant infections over the past 5 years, the management strategy and to identify predictive factors that led to explantation. STUDY DESIGN: Retrospective record-base case series of cochlear implant infections. SETTING: Tertiary otology and implant center. PATIENTS: All patients who had cochlear implantation over a period of 5 years. INTERVENTION(S): None. MAIN OUTCOME MEASURE(S): To identify risk factors, rates and outcomes of cochlear implant infections, and to formulate strategies to develop clearer management protocols to prevent cochlear implant explantation. RESULTS: Of 704 implanted patients, 22 suffered a postoperative soft tissue infection (3%). Fifty-nine percent of these infected patients resulted in explantation, giving an explantation rate of 1.8% over the whole study population. One hundred percent of the infected implants identified as having either Staph. Aureus or Pseudomonas spp. as the single causative organism resulted in explantation. CONCLUSIONS: There is a high rate of explantation when infection is detected. Currently there is no clear consensus on medical management, such as choice of antibiotics or length of antibiotic course. A registry of cochlear implants would facilitate standard reporting methods for severity and type of infection, to be able to pool data across centers and form a more robust management protocol for cochlear implant infections.

Hearing rehabilitation outcomes in cochlear implant recipients with vestibular schwannoma in observation or radiotherapy groups: A systematic review.

Objectives: Vestibular schwannomas (VS) are rare benign tumours of the vestibular nerve that cause hearing loss. Management strategies include watchful waiting, radiotherapy or surgical resection. Historically, the presence of retrocochlear disease has been considered to be a contra-indication to cochlear implantation (CI). The aim of this systematic review is to assess hearing rehabilitation outcomes for CI recipients with VS, either sporadic or associated with neurofibromatosis type 2, whose tumours have been managed with either observation or radiotherapy.Methods: PubMed, Embase, and Cochrane Library databases were searched from inception through to November 2018. 50 cases from 12 studies met the inclusion criteria. Patient demographics, VS characteristics, management strategy, pre-CI hearing status, electrical promontory stimulation testing, post-CI hearing status and speech perception scores, functional benefits and follow-up length are reported.Results: Radiotherapy and observation groups had similar patient demographics in terms of age at CI, tumour size and duration of deafness. Following CI, 64% and 60% of patients in the radiotherapy and observation groups achieved open-set speech perception, respectively. Pure tone average thresholds (33 vs. 39 dB) and speech scores were also comparable between both groups.Conclusion: Ipsilateral CI in patients with VS that have not been surgically resected can provide beneficial hearing rehabilitation outcomes.

Performing MRI Scans on Cochlear Implant and Auditory Brainstem Implant Recipients: Review of 14.5 Years Experience.

OBJECTIVE: To assess the complication rate of magnetic resonance imaging (MRI) using 1.5 T scanners on cochlear implant (CI) and auditory brainstem implant (ABI) recipients over 14.5 years. METHODS: Prospective study conducted in a tertiary referral center for cochlear and auditory brainstem implantation, including patients with neurofibromatosis 2. The primary outcome was complications related to MRI scanning in implant recipients, including failure to complete MRI sessions. The secondary outcome was magnet void size due to MRI scanning with magnet in situ. RESULTS: Ninety-seven patients (21 ABI recipients, 76 CI recipients of whom 23 were bilateral) underwent a total of 428 MRI sessions consisting of 680 MRI procedures, which generated 2,601 MRI sequences (excluding localizers). Of these, 28/428 (6.5%) MRI sessions were performed with magnet removed, and the remaining 400/428 (93.4%) with the magnet in situ. The overall complication rate per session was 15/428 (3.5%). The majority of complications were accounted for by patient discomfort, in some cases requiring abandoning the scan session, but 5 magnet dislocations were also recorded. There were no cases of implant device failure or excessive demagnetization of the receiver stimulator magnet.For CI and ABI recipients, the implant caused large voids of around 110 mm × 60 mm with the magnet in situ which reduced to 60 mm × 30 mm when the magnet was removed. However, it was usually possible to visualize the internal acoustic meatus and cerebellopontine angle by positioning the implant package higher and further forward compared with conventional positioning. CONCLUSION: MRI scanning in ABI and CI recipients is generally safe and well tolerated without magnet removal, and carries a low rate of complications. However, patients should be fully informed of the possibility of discomfort, and precautions such as local anesthetic injection and head bandaging may reduce the likelihood of adverse events.

Advances in Eustachian tube function testing.

Obstructive and patulous Eustachian tube dysfunction provide a significant diagnostic and management challenge. The development of new treatments such as balloon Eustachian tuboplasty has generated renewed interest in measuring Eustachian tube function, as a method of selecting appropriate patients for intervention, and measuring their treatment outcomes. This review summarises recent findings relating to Eustachian tube function assessment. Increasingly it is recognised that patient reported outcome measures based on symptoms are highly non-specific and non-diagnostic, and clinical assessment alone may not permit the selection of individuals with abnormal Eustachian tube opening. Tests of Eustachian tube opening therefore may represent a practical and objective addition to patient assessment in clinic, allowing the identification of individuals with abnormal (patulous or obstructive) Eustachian tube function. A diagnostic pathway is described on this basis. More work is required to validate the described Eustachian tube function tests, and there remain individuals, such as those with dysfunction limited to pressure challenges, in whom function tests have yet to fully characterise the disorder.

Repair of subtotal tympanic membrane perforations: A temporal bone study of several tympanoplasty materials.

The aim of this project was to investigate the effects of different types of graft material, and different remaining segments of the native TM on its motion. In twelve human temporal bones, controlled TM perforations were made to simulate three different conditions. (1) Central perforation leaving both annular and umbo rims of native TM. (2) Central perforation leaving only a malleal rim of native TM. (3) Central perforation leaving only an annular rim of native TM. Five different graft materials (1) perichondrium (2) silastic (3) thin cartilage (4) thick cartilage (5) Lotriderm® cream were used to reconstruct each perforation condition. Umbo and stapes vibrations to acoustic stimuli from 250 to 6349 Hz were measured using a scanning laser Doppler vibrometer. Results showed that at low frequencies: in the Two Rims condition, all grafting materials except thick cartilage and Lotriderm cream showed no significant difference in umbo velocity from the Normal TM, while only Lotriderm cream showed a significant decrease in stapes velocity; in the Malleal Rim condition, all materials showed a significant decrease in both umbo and stapes velocities; in the Annular Rim condition, all grafting materials except Lotriderm and perichondrium showed no significant difference from the Normal TM in stapes velocity. Umbo data might not be reliable in some conditions because of coverage by the graft. At middle and high frequencies: all materials showed a significant difference from the Normal TM in both umbo and stapes velocities for all perforation conditions except in the Annular Rim condition, in which silastic and perichondrium showed no significant difference from the Normal TM at umbo velocity in the middle frequencies. In the low frequencies, the choice of repair material does not seem to have a large effect on sound transfer. Our data also suggests that the annular rim could be important for low frequency sound transfer.