Implantable hearing devices: the Ototronix MAXUM system

Results and Quality of Life after Implantation of Active Middle Ear Implants

The provision of implantable hearing aids represents an area with high development and innovation potential. On the one hand, this review article provides an overview of current indication criteria for the treatment with active middle ear implants. On the other hand, outcome parameters as well as functional results after implantation of active middle ear implants are demonstrated and discussed. The focus is mainly placed on audiological results as well as the subjective health status. "Patient Reported Outcome Measures" (PROMs) have become an integral part of the evaluation of hearing implant treatment. Due to low evidence level criteria, the study situation regarding audiological as well as subjective outcome parameters is not satisfactory. The lack of an international consensus on accepted outcome parameters makes a meta-analytical analysis of results immensely difficult. In the studies published to date, patients with sensorineural hearing loss and patients with conductive or mixed hearing loss offered better speech recognition after implantation of an active middle ear implant compared to conventional hearing aids. Current analyses show a significant improvement in general as well as hearing-specific quality of life after implantation of an active middle ear implant. To date, no validated, hearing-specific quality-of-life measurement instruments exist for assessing the success of fitting in children. Especially in children with complex malformations of the outer ear and the middle ear, excellent audiological results were shown. However, these results need to be substantiated by quality-of-life measurements in future.

Systematic and audiological indication criteria for bone conduction devices and active middle ear implants

Certain patients with conductive or mixed hearing loss can benefit from bone-conduction hearing devices or active middle ear implants. Available devices differ in coupling site, energy transfer from the sound processor to the implant, and the active or passive actuator technology. The audiological benefit of those devices depends on the maximum stable power output and the noise floor of the device, the degree and expected stability of the sensorineural hearing loss and the coupling efficiency with the aim on achieving a minumum of 30-35 dB effective dynamic range. The choice of the device is often a trade-off between the optimal audiological solution with respect to the hearing loss, technical device-related parameters and the expected coupling efficiency, the optimal surgical solution with respect to patho-anatomical aspects, device dimensions and the coupling site, invasiveness or surgical risks, and other patient factors with respect to the patients' wish and expectations, social aspects, device usability and connectivity. This review article lists all currently available implantable and conventional bone-conduction hearing devices and active middle ear implants with respect to technical features like maximum power output, market availability, and the expected effective output dynamic range.

Polyharmonic Vibrations of Human Middle Ear Implanted by Means of Nonlinear Coupler

This paper presents a possibility of quasi-periodic and chaotic vibrations in the human middle ear stimulated by an implant, which is fixed to the incus by means of a nonlinear coupler. The coupler represents a classical element made of titanium and shape memory alloy. A five-degrees-of-freedom model of lumped masses is used to represent the implanted middle ear for both normal and pathological ears. The model is engaged to numerically find the influence of the nonlinear coupler on stapes and implant dynamics. As a result, regions of parameters regarding the quasi-periodic, polyharmonic and irregular motion are identified as new contributions in ear bio-mechanics. The nonlinear coupler causes irregular motion, which is undesired for the middle ear. However, the use of the stiff coupler also ensures regular vibrations of the stapes for higher frequencies. As a consequence, the utility of the nonlinear coupler is proven.

Safety of active auditory implants in magnetic resonance imaging

Magnetic resonance imaging (MRI) has become the gold standard for the diagnosis of many pathologies. Using MRI in patients with auditory implants can however raise concerns due to mutual interactions between the implant and imaging device, resulting in potential patient risks. Several implant manufacturers have been working towards more MRI safe devices. Older devices are however often labelled for more stringent conditions, possibly creating confusion with patients and professionals. With this myriad of different devices that are implanted in patients for lifetimes of at least 20 years, it is crucial that both patients and professionals have a clear understanding of the safety of their devices. This work aims at providing an exhaustive overview on the MRI safety of active auditory implants. The available industry standards that are followed by manufacturers are outlined and an overview of the latest scientific developments focusing on the last five years is provided. In addition, based on the analysis of the adverse events reported to the Food and Drug Administration (FDA) and in literature within the past ten years, a systematic review of the most commonly occurring issues for patients with auditory implants in the MRI environment is provided. Results indicate that despite the release of more MRI conditional active hearing implants on the market, adverse events still occur. An extensive overview is provided on the MRI safety of active auditory implants, aiming to increase the understanding of the topic for healthcare professionals and contribute to safer scanning conditions for patients.

Implantable Hearing Aids: Where are we in 2020?

Beginning in the late 20th century, implantable hearing aids were developed and used as an alternative for individuals who were unable to tolerate conventional hearing aids. Since that time, several devices have been developed, with four currently remaining on the international market (Med-el Vibrant Soundbridge, Envoy Esteem, Ototronix MAXUM, and Cochlear Carina). This review will briefly examine the history of middle ear implant development, describe current available devices, evaluate the benefits and limits of the technology, and consider the future directions of research in the field of implantable hearing aids.

Ossicle Coupling Active Implantable Auditory Devices: Magnetic Driven System

Active auditory implants, such as the Maxum, provide significantly improved hearing function compared to hearing aids in patients with moderate to severe hearing loss who are not reaching their cochlear hearing potential. The speech perception gap (SPG), defined as PB Max (phonetically balanced maximum) minus word recognition score with hearing aid, is a useful measure of inadequate hearing aid performance. The Maxum middle ear implant provides significantly improved performance over hearing aids in patients with significant SPG because of superior high frequency gain. Patients with PB Max 60% or greater with SPG are possible candidates for the implant.

Implantable Auditory Devices: Financial Considerations and Office-Based Implantation

Hearing rehabilitation has been recognized as a crucial tool to maintain communicative and social skills. The availability of hearing aids and auditory implants ought not be limited to the wealthy and to those who can afford them. Multidisciplinary efforts in reducing costs are necessary and include reduction of the item costs, insurance coverage, and the ability to perform certain procedures in an office setting, eliminating hospital and facilities fees and anesthesia bills.

The development of active middle ear implants: A historical perspective and clinical outcomes

Objective s

Energy emitting, active middle ear implants (aMEI) have taken more than two decades of research to reach technological sophistication, medical safety, and regulatory approval to become a powerful tool in treating sensorineural, conductive, and mixed hearing loss. The present review covers this era.

Data Source

Literature found from searching Pubmed (MEDLINE); EMBASE, SciSearch, German Medical Science Journals and Meetings, and The Cochrane Library; and published as of February 2017. Study bibliographies were hand-searched to find further materials.

Methods

A systematic literature review was conducted to identify studies evaluating the safety, efficacy, effectiveness, and subjective outcomes of partially implantable aMEIs. Data were extracted on systems with regulatory approval and summarized narratively. Meta-analyses were conducted for aMEIs with more than 25 publications. Study selection, data extraction, and quality appraisal for quantitative data synthesis was carried out by two reviewers.

Results

Four hundred thirty-one studies included in narrative synthesis describe that albeit good audiological outcomes, clinical safety and (dis)investment are major barriers to continued market access. The synthesised risk of adverse events was three fold with the MET than with the VIBRANT SOUNDBRIDGE. With the latter system, audiological outcomes were stable and similar for all indications and age groups.

Conclusion

To date, the majority of the literature covers the clinical application of the VIBRANT SOUNDBRIDGE system as it is applicable to a wide range of otologic and audiological conditions, particularly with the introduction of couplers to extend its clinical reach. The MAXUM and MET still have to find their way into surgical routine.Level of Evidence.

Comparison of an Electromagnetic Middle Ear Implant and Hearing Aid Word Recognition Performance to Word Recognition Performance Obtained Under Earphones

OBJECTIVE

To report the results of patients with the Maxum middle ear implant (MEI) and compare word recognition scores (WRS) and speech perception gap (SP Gap) of Maxum versus optimally fit hearing aids (HA).

STUDY DESIGN

Case series with chart review.

SETTING

Single, private otology clinic.

PATIENTS

Eleven ears, in nine adult patients (two women; average age 62.7 yr).

INTERVENTIONS

Twelve consecutive ears with moderate to severe sensorineural hearing loss (SNHL) underwent implantation of the Maxum system. One patient was not included due to inadequate preoperative testing.

MAIN OUTCOME MEASURES

Primary outcome measures included word recognition score (WRS) and SP Gap (maximum word understanding [PB max] - WRSaided) improvement compared with HAs.

RESULTS

The average Maxum WRS was 64.7% (range, 28-94%), a 41.6% improvement (range, 10-66%) over HAs (p < 0.001). The average Maxum SP Gap was 6.6% (range, -8 to 24%), a 41.6% improvement (range, 10-66%) over HAs (p < 0.001).

CONCLUSION

These data demonstrate that the Maxum provides superior WRS than HAs for patients with significant aided SP Gaps. There is a significant, very strong correlation between Maxum WRS and PB max (r = 0.85, p = 0.001). This implies that PB max may reasonably predict WRS outcomes with Maxum before implantation, and the SP Gap can reasonably predict the degree of additional potential benefit with Maxum. In advising patients who may be candidates for both a CI and MEI, PB max and SP Gap measurements will provide useful predictive information to help clinicians counsel patients on their choice of hearing technology.

LEVEL OF EVIDENCE

4.

Factors associated with benefit of active middle ear implants compared to conventional hearing aids

OBJECTIVE

Identify factors associated with benefit of middle ear implants (MEIs) as compared to conventional hearing aids (HAs).

STUDY DESIGN

Independent review of audiological data from a multicenter prospective U.S. Food and Drug Administration (FDA) clinical trial. Preoperative and postoperative earphone, unaided/aided/implanted pure-tone thresholds, and word recognition scores were evaluated.

RESULTS

Ninety-one subjects were included in this study. Mean word recognition was better with MEIs than with HAs (81.8% ± 12.0% vs. 77.6% ± 14.6%, P = 0.035). Word recognition with MEIs showed a low positive correlation with word recognition measured with earphones (r = 0.25, P = 0.016) and a moderate positive correlation with aided word recognition (r = 0.42, P < 0.001). Earphone word recognition alone was not predictive of MEI benefit over HA benefit (r = 0.09, P = 0.41), unlike differences between scores with earphone and HAs (earphone-aided differences [EAD]) (r = 0.62, P < 0.011). As compared to those with -EADs, subjects with +EADs showed greater improvement in word recognition from unaided to implanted and from HAs to implanted (P < 0.0001). Using the 95% CI for word recognition scores, 16 subjects showed significantly higher scores with the MEI than with HAs. Of those, 14 had +EAD.

CONCLUSION

Word recognition benefit derived from conventional HAs and MEIs from this large, multi-center FDA trial provides further evidence of the importance of aided word recognition in clinical decision making, such as determining candidacy for and success with MEIs.

LEVEL OF EVIDENCE

2b. Laryngoscope, 128:2133-2138, 2018.

Implantable hearing devices

Combined hearing loss is an essential indication for implantable hearing systems. Depending on the bone conduction threshold, various options are available. Patients with mild sensorineural deafness usually benefit from transcutaneous bone conduction implants (BCI), while percutaneous BCI systems are recommended also for moderate hearing loss. For combined hearing losses with moderate and high-grade cochlear hearing loss, active middle ear implants are recommended. For patients with incompatibilities or middle ear surgery, implants are a valuable and proven addition to the therapeutic options.

The ototronix MAXUM middle ear implant for severe high-frequency sensorineural hearing loss: Preliminary results

OBJECTIVES/HYPOTHESIS

To report the preliminary results of the Ototronix MAXUM middle ear implant for treatment of severe high-frequency sensorineural hearing loss.

STUDY DESIGN

Case series with chart review.

METHODS

Six consecutive ears with severe high-frequency sensorineural hearing loss (≥75 dB HL at 2, 3, and 4 kHz) and poor aided word recognition performance (≤60% single words) underwent implantation of the MAXUM system at a single, private otologic referral center. Primary outcome measures included frequency-specific functional gain and word recognition score improvement compared to optimally fitted hearing aids.

RESULTS

Six ears, in four adult patients (two female; median age 67.5 years) were included. The median unaided preoperative high-frequency pure-tone average (HFPTA) (2, 3, and 4 kHz) was 80.0 dB (range, 75.0-85.0 dB), and the median best-aided word recognition score was 48.0% (range, 24%-60%). The median HFPTA functional gain with the MAXUM system was 47.2 dB, a 25.0 dB improvement (range, 16.7-33.3 dB) (P = .03) over optimally fit hearing aids, and the median word recognition score with MAXUM was 81.5%, a 42.0% improvement (range, 20%-48%) (P = .03) with the MAXUM middle ear implant over optimally fitted hearing aids.

CONCLUSIONS

These preliminary data demonstrate that the MAXUM middle ear implant provides superior functional gain and word recognition scores in quiet for patients with severe high-frequency sensorineural hearing loss compared to optimally fitted hearing aids. Future studies with greater patient numbers and patient reported outcome measures are needed to confirm these promising but preliminary results.

LEVEL OF EVIDENCE

4 Laryngoscope, 126:2124-2127, 2016.