Multicenter audiometric results with the Vibrant Soundbridge, a semi-implantable hearing device for sensorineural hearing impairment

Comparison between incus short process and long process coupling of the vibrant soundbridge in human temporal bones

OBJECTIVE

The Vibrant Soundbridge (VSB) is one of the most widely used implantable hearing devices. It consists of a vibrating floating mass transducer (FMT) that is connected to a middle ear structure. The standard coupling devices for sensorineural hearing loss are short process (SP) or long process (LP) couplers.

DESIGN AND STUDY SAMPLE

This study directly compared the electro-mechanical performance of the SP- and LP-coupled FMT of the VSB in the same temporal bone specimen (n = 10). We measured velocity magnitudes and total harmonic distortions (THD) of the stapes (ST) and the round window (RW) using laser Doppler Vibrometry (LDV).

RESULTS

Comparison shows a maximally 10 dB higher magnitude for the LP coupler at ST and RW for frequencies below 600 Hz, whereas the SP coupler shows a maximally 20 dB higher magnitude at the ST and RW for frequencies above 600 Hz. THD show similar behaviour with less distortion at 500 Hz for the LP coupler and less distortions for the SP coupler in higher frequencies.

CONCLUSIONS

Our experiments showed that the SP coupling may be mechanically favourable, in terms of magnitude and distortion, for the transmission of FMT vibrations at higher frequencies.

Hearing rehabilitation and microbial shift after middle ear surgery with Vibrant Soundbridge in patients with chronic otitis media

INTRODUCTION

Patients with otitis media (OM) encounter significant functional hearing impairment with conductive, or a combined hearing loss and long-term sequelae involving impaired speech/language development in children, reduced academic achievement and irreversible disorders of middle and inner ear requiring a long time therapy and/or multiple surgeries. In its persistent chronic form, Otitis media (COM) can often only be treated by undergoing ear surgery for hearing restoration. The persistent inflammatory reaction plays a major role, often caused by multi-resistant pathogens in the ear. Herein, we present outcomes of patients implanted with currently the only FDA approved active Middle Ear Implant Vibrant Soundbridge (VSB), suffering from persistent COM.

METHODS

The study enrolled 42 patients, treated by performing middle ear (ME) surgery to different extents and implanted with the VSB to various structures in the ME. Included were 17 children and 25 adults that had recurrent and/or persisting OM and significant hearing loss. Preoperative and postoperative patients' audiometric data were evaluated and the benefit with VSB assessed using the Glasgow Benefit Inventory for adults and pediatric cohorts. The microbial spectrum of pathogens was assessed before and after surgery, exploring the colonization of the otopathogens, as well as the intestinal microbiome from individually burdened patients.

RESULTS

The mean functional gain is 29.7 dB HL (range from 10 to 56.2 dB HL) with a significant improvement in speech intelligibility in quiet. Following VSB implantation, no significant differences in coupling were observed at low complication rates. Postoperatively patients showed significantly increased benefit with VSB compared to the untreated situation, including less otorrhea, pain, medical visits, and medication intake, with no recurrent OM and significant bacterial shift in otopathogens. The analysis of the intestinal microbiome displayed a high abundance of bacterial strains that might be linked to chronic and persistent inflammation.

CONCLUSIONS

Functional ear surgery including rehabilitation with a VSB in patients suffering from COM present to be safe and effective. The successful acceptance accompanied by the improved audiological performance resulted in significant benefit with VSB, with a shift in the ear pathogens and altered microbiome and thus is a great opportunity to be treated.

Long-Term Safety and Quality of Life after Vibroplasty in Sensorineural Hearing Loss: Short/Long Incus Process Coupler

OBJECTIVE

The study shows the long-term effectiveness, safety, and quality of life after Vibrant Soundbridge (VSB) implantation in sensorineural hearing loss (SNHL) using the short process coupler (SP) or the long process coupler (LP).

METHODS

This retrospective study evaluated 77 VSB cases. Follow-up (F/U) time-dependent objective measurements (audiological outcomes), subjective data collection (quality-of-life questionnaire), and safety measures are presented.

RESULTS

Sixty-two ears were included in the analysis with up to 116 months of postsurgical F/U data (mean 32.15 ± 37.97 months LP and SP coupler). Fifty-three ears (13 bilateral cases) received the LP coupler and 9 subjects the SP coupler. The post-operative bone conduction thresholds remained stable and, in both groups, <10 dB. The benefit in word recognition scores measured at 65 dB SPL and 80 dB SPL showed no significant difference between the couplers (p = 0.559 and p = 0.088, respectively). The functional gain was not significantly different (p > 0.05) with a mean of 20.91 ± 9.77 and 17.19 ± 5.75 for LP and SP coupler, respectively. The utility score deciphered from the Assessment of Quality-of-life Questionnaire-8 dimensions revealed a mean score of 0.75 ± 0.16 which is not significantly different to the age- and sex-matched healthy control group with 0.81 ± 0.02 (p = 0.3547).

CONCLUSION

The Incus Vibroplasty utilizing both couplers is a safe and effective method to treat mild-to-severe SNHL. Both fixation methods of the floating mass transducer exhibit good clinical and audiological outcomes with high patient quality of life. The SP coupling method can be a good alternative when the long process is anatomically inaccessible, or the approach is limited due to anatomical reasons.

Feasibility and Efficacy of Vibrant Soundbridge Short Process Coupler in Patients With Aural Atresia

OBJECTIVES

Different options are available for hearing restoration in patients with aural atresia. Middle ear implantation with the Vibrant Soundbridge (VSB) has been used successfully in many patients with aural atresia with conductive or mixed hearing loss. The aim of the current study was to assess the safety and the efficiency of VSBs coupled to the short process of the incus in patients with aural atresia with conductive or mixed hearing loss.

METHODS

The study was a retrospective chart review conducted at a tertiary university hospital. Audiological and surgical data from six ears with aural atresia implanted with VSBs coupled to the short process of the incus were analyzed. The audiological results were compared with previously reported results obtained after the utilization of different coupling techniques.

RESULTS

All six atretic ears were successfully implanted using the short process coupler, and there were no major complications. Postoperative bone conduction thresholds did not differ substantially from preoperative thresholds. The respective mean preoperative pure-tone average 4, speech reception threshold, and word recognition score values were 56.7 dB, 61.7 dB, and 44%. Postoperative pure-tone average 4 thresholds (25 ± 3.5 dB) and speech reception thresholds (20.8 ± 8 dB) were significantly improved. The maximum postoperative word recognition score achieved was 100%. The audiological outcomes obtained were similar to previously reported outcomes after classic stapes placement.

CONCLUSION

Coupling of the floating mass transducer to the short process of the incus in patients with aural atresia resulted in significant audiological improvements that were comparable to previously reported improvements after placement via other methods.

Direct Drive Simulation-Preoperative Sound Simulation of "Vibroplasty-Hearing" in Patients With Mixed Hearing Loss

OBJECTIVE

Validation of the preoperative sound simulation test for vibroplasty-hearing so-called "Direct Drive Simulation" (DDS) in case of mixed hearing loss.

STUDY DESIGN

Retrospective data analysis.

SETTING

Tertiary referral center with a large hearing implant program.

MAIN OUTCOME MEASURE

Comparison of sound impression during preoperative Direct Drive Simulation, and postoperative testing with the activated active middle ear implant (AMEI) under free-field condition and in daily routine.

PATIENTS

Fifty-four data sets from 18 patients with mixed hearing loss with a mean age of 60.78 ± 3.18 were included.

RESULTS

Comparing the sound impression during DDS preoperatively versus free-field testing with the implanted AMEI, no significant differences were found. DDS offers a slightly better sound quality than the AMEI in daily routine, fitting well to the ideal listening situation in DDS versus some background noise in daily routine.

CONCLUSION

The DDS offers the possibility of a realistic preoperative sound simulation of the "vibroplasty-hearing" in cases of mixed hearing loss. This probably facilitates patient's decision towards a vibroplasty. The audiologist as well as the surgeon get additional information regarding the indication especially when audiologic inclusion criteria are critical. Thus, the DDS is a useful extension of preoperative diagnostics before vibroplasty.

ACTIVE MIDDLE EAR VIBRANT SOUNDBRIDGE SOUND IMPLANT

The Vibrant Soundbridge represents a new approach to hearing improvement in the form of active implantable middle ear hearing device. Unlike conventional acoustic hearing aids, which increase the volume of sound that goes to the eardrum, the Vibrant Soundbridge bypasses the ear canal and eardrum by directly vibrating the small bones in the middle ear. Because of its design, no portion of the device is placed in the ear canal itself. The Vibrant Soundbridge has been approved by the FDA as a safe and effective treatment option for adults with moderate to severe sensorineural, conductive or mixed hearing losses who desire an alternative to the acoustic hearing aids, for better hearing. The paper presents a review of the active middle ear implant Vibrant Soundbridge, which has been also implanted at the Department of Otorhinolaryngology and Head and Neck Surgery, Sestre milosrdnice University Hospital Center, which is the Referral Center for Cochlear Implantation and Surgery of Hearing Impairment and Deafness of the Ministry of Health, Republic of Croatia.

The Vibrant Soundbridge: A Global Overview

The Vibrant Soundbridge is a semi-implantable, active middle ear implant that is a safe and effective treatment for patients with sensorineural hearing loss. Since Food and Drug Administration approval for this indication, many international investigators have expanded its use for conductive and mixed hearing losses. This article reviews the author's experience and the international uses of this versatile device.

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.

The Hannover Coupler: Controlled Static Prestress in Round Window Stimulation With the Floating Mass Transducer

INTRODUCTION

Stimulation of the cochlear round window (RW) with the floating mass transducer (FMT) still suffers from large variation in clinical outcomes. Beside the geometric mismatch between RW and FMT diameter that is a known limiting factor in achieving optimal coupling between actuator and RW membrane, the applied static force between FMT and RW is usually undefined. In this study, the feasibility and efficacy of a specially designed FMT coupler permitting application of static preloads to the RW membrane to optimize FMT-RW coupling was investigated.

METHODS

Experiments were performed in fresh human cadaveric temporal bones. The "Hannover Coupler" FMT-prosthesis has a spherical tip (d=0.5 mm) at the front end and a spring at the prosthesis back that enables the application of static preloads and mobility of the FMT at the same time. Stapes footplate (SFP) displacements in response to acoustic stimulation of the tympanic membrane and to RW stimulation by the FMT were measured by a Laser-Doppler vibrometer.

RESULTS

Average SFP displacement responses of ASTM standard F2504-05 compliant temporal bones to RW stimulation by the "Hannover Coupler" were dependent on the applied force (∼0-100 mN) and increased by up to 25 dB at frequencies ≥ 1 kHz. When averaged at speech relevant frequencies (0.5, 1, 2, 4 kHz) SFP displacements showed a global maximum at RW preloads of ∼4 mN.

CONCLUSION

The coupling between FMT and RW membrane was improved by the application of static RW preloads as indicated by increased SFP amplitudes to RW stimulation.

Results of VSB implantation at the short process of the incus in children with ear atresia

OBJECTIVE(S)

To describe a new and more simple surgical procedure for implanting the Vibrant Soundbridge (VSB) on the short process of the incus in children with ear atresia and atretic plate and present the audiometric results.

METHODS

Since 2014, pre- and post-operative audiometric tests with tonal and vocal audiometryat the maximal follow up, respectively 33, 22 and 12 months were performed after VSB implantation at the ENT department, Necker Enfants Malades Hospital, Paris, France. 3 children aged 11, 9 and 15 years with conductive hearing loss due to high grade ear atresia and absent ear canal were implanted. The malformed and fused malleus-incus complex was found to be immobile in two of the subjects, who then underwent a superior tympanotomy to carefully remobilize the malleus. Stapes were mobile in all cases. The FMT clip was customized and crimped on the short process, stabilized by the metallic wire.

RESULTS

At the maximum follow-up time, the bone conduction was unchanged, and the mean aided ACPTA was 21 dB, 29 dB and 30 dB, compared to 66 dB, 63 dB and 68 dB unaided, respectively. The word recognition score (WRS) at 65 dB SPL increased from 10%, 10% and 70% (unaided) respectively to 100% (aided).

CONCLUSIONS

The long process of the incus is usually very hypoplastic in patients with ear atresia with a fused malleus-incus complex lateral to the stapes. VSB coupling to the long process of the incus or the stapes may be challenging in small mastoids. Coupling to the short process of the incus is comparatively a simple procedure, since there is no need for posterior tympanotomy and has no proximity to the facial nerve. The results of this study are similar to other ear atresia cases in the literature with classic FMT placement on the stapes or long process of the incus. Outcomes should be confirmed in a larger number of patients.

THE EFFECT OF IMPLANTABLE TRANSDUCERS ON MIDDLE EAR TRANSFER FUNCTION — A COMPARATIVE NUMERICAL ANALYSIS

Several types of middle ear implants (MEIs) have been invented as an alternative to conventional hearing aids for the rehabilitation of sensorineural hearing loss. Temporal bone and clinical studies have shown that the implantation of MEIs’ transducers influences middle ear transfer function. But there is little comparative data available about these influences. We conducted comparative studies on the influences of three principal types of MEI transducers in respect to their attachment points on the ossicular chain. To aid the investigation, a human middle ear finite element model was constructed. The model was built based on a complete set of micro-computerized tomography section images of a human ear by reverse engineering technology. The validity of the developed model was verified by comparing the motions obtained by this model with published experimental measurements on human temporal bones. The results show that the eardrum driving transducer (EDT) and the floating mass transducer (FMT) decrease stapes displacement prominently at high frequencies. The greater these transducers’ mass, the smaller is the displacement of the stapes footplate. In contrast, the incus body driving transducer (IBDT) decreases stapes displacement severely at low frequencies, and its adverse effect on residual hearing increases with increasing stiffness of the IBDT’s driving rod.

Standardized Active Middle-Ear Implant Coupling to the Short Incus Process

INTRODUCTION

Active middle-ear implants with floating-mass transducer (FMT) technology are used to treat mild-to-severe sensorineural hearing losses. The standard surgical approach for incus vibroplasty is a mastoidectomy and a posterior tympanotomy, crimping the FMT to the long incus process. An alternative fixation side with less surgical trauma might be the short incus process and incus body.The aim of this study was to develop and test a short incus process coupling device for its functional properties in temporal bone preparations and clinical practice.

MATERIALS AND METHODS

An extended antrotomy and a posterior tympanotomy were performed in 10 fresh human temporal bones. As a control for normal middle-ear function, the tympanic membrane was stimulated acoustically, and the vibration of the stapes footplate was measured using laser Doppler vibrometry. FMT-induced vibration responses of the stapes were then measured for standard attachment at the long process and for 2 types of couplers designed for attachment at the short process of the incus (SP1 and SP2 coupler). Additionally, the functional outcome in 2 patients provided with an SP2 coupler was assessed postoperatively at 2 weeks, 3 months, and then 11 months, using pure-tone audiometry, auditory thresholds for frequency-modulated (warble) tones, vibroplasty thresholds, and speech audiometry in quiet and noise.

RESULTS

For the SP2 coupler, velocity-amplitude responses in temporal-bone preparations showed generally similar mean amplitudes as compared with the standard coupling of the FMT to the long process but with clearly increased mean amplitudes between 0.7 and 1.5 kHz and with reduced interindividual variation between 0.5 and 3 kHz. The clinical data of 2 patients with mild-to-severe sensory hearing loss showed good vibroplasty thresholds and convincing results for speech audiometry in quiet (Freiburger monosyllables at 65 dB SPL, 23 ± 31% unaided versus 83 ± 4% aided) and noise (Hochmair-Schulz-Moser-test at 65 dB SPL at 10 dB SNR, 32 ± 45% unaided and 42 ± 29% aided).

CONCLUSION

The attachment of the FMT to the short incus process with the SP2 coupler leads to good mechanical and functional coupling in an experimental setup and clinical practice.

Subtotal petrosectomy and Codacs™: new possibilities in ears with chronic infection

Subtotal petrosectomy combined with obliteration of the tympanomastoid is a standard procedure to treat temporal bones in patients with radical cavity and chronic infections. Currently, patients with profound-to-severe sensorineural hearing loss are often fitted with cochlear implants. In the case of profound mixed hearing loss, active middle ear implants have been used successfully. The new Codacs™ system provides an effective treatment for patients with severe-to-profound mixed hearing loss; however, only aerated middle ears have been treated with this device. The question arises whether the Codacs™ can be implanted in patients with radical cavity or ears with chronic otorrhea. Of the 41 patients who were implanted with the Codacs™ at the department, 4 received the device after subtotal petrosectomy and obliteration with abdominal fat. Clinical and audiological results were assessed. The device was implanted without any complications in the obliterated subtotal petrosectomy. The preliminary results of the first two patients showed stable bone conduction thresholds and indicated improved speech intelligibility in quiet and noise. Implanting the Codacs™ device after subtotal petrosectomy and obliteration with abdominal fat has been proven to be a feasible and suitable procedure for patients with radical cavity or chronic otorrhea. The speech intelligibility outcome directly after activation was comparable to patients with aerated middle ears.

Comparison of two different titanium couplers for an active middle ear implant

OBJECTIVE

To compare surgical methods, functional gain, and speech discrimination using two different coupling methods for an active middle ear implant. Of several couplers enabling placement of the active element at various locations, two function directly at a cochlear membrane, bypassing a missing or malformed ossicular chain. This study evaluates whether either of these methods is more beneficial.

STUDY DESIGN

Retrospective case review.

SETTING

ENT surgical clinic.

PATIENTS

Forty-seven German-speaking patients with moderate to severe mixed hearing loss.

INTERVENTIONS

Records of patients implanted with either a round window (RW) or oval window (OW) coupler and active implant were examined. Preoperative and postoperative bone and air-conduction thresholds, auditory gain, and speech perception were compared.

MAIN OUTCOME MEASURES

Functional gain, Freiburger monosyllables in quiet.

RESULTS

The range of hearing benefit shown by functional gain in patients implanted with the RW coupler (median) was between 22.5 dB (at 0.25 kHz) and 52.5 dB (2 and 3 kHz). In the OW group, improvement was similar, ranging from 21 dB (at 8 kHz) to 50 dB (1 and 2 kHz). Patients in both groups showed a similar improvement in speech recognition. Median preoperative unaided word recognition was 0% at 60 dB HL for both patient groups, improved postoperatively in both groups to median 85% correct at 65 dB HL and 95% at 80 dB HL.

CONCLUSION

Placement of an active middle ear implant using the RW and the OW coupler was found to be safe, although the surgical methods differ. Safety and efficacy of both couplers present no significant differences.

Vibroplasty for mixed and conductive hearing loss

OBJECTIVE

To summarize new application methods of an active middle ear implant (Vibrant Soundbridge) in patients with conductive or mixed hearing loss.

DATA SOURCES

Publications listed in the Medline/PubMed database.

STUDY SELECTION

All publications published in English language; search term Vibrant Soundbridge AND floating mass transducer in all fields.

DATA EXTRACTION

Structured analysis of all publications.

DATA SYNTHESIS

Extraction of significant findings and conclusions and audiometric data.

CONCLUSION

Modern application methods of an active middle ear implant (VSB) open new therapeutic options for patients with various outer and middle ear diseases resulting in conductive or mixed hearing loss. Titanium couplers can help to couple the active middle ear implant in a standardized way to remnants of the ossicular chain or to the round window. Thus, the active middle ear implant has been established as an alternative treatment option for patients with mixed and conductive hearing. However, the heterogeneity of the studies published so far complicates the analysis of the audiometric results, and thus, the functional hearing gain after VSB implantation varies a lot.

Alternative fixation of an active middle ear implant at the short incus process

INTRODUCTION

Since 1996, the preferred approach for positioning the active middle-ear implant Vibrant Soundbridge© is a mastoidectomy and a posterior tympanotomy. With this device, placement of the floating mass transducer (FMT) on the long incus process is the standard method for treatment of mild-to-severe sensorineural hearing loss in the case of normal middle-ear anatomy. The aim of this study was to determine the vibrational effectiveness of FMT placement at the short incus process.

MATERIALS AND METHODS

An extended antrotomy and a posterior tympanotomy were performed in 5 fresh human temporal bones. As a control for normal middle-ear function, the tympanic membrane was stimulated acoustically and the vibration of the stapes footplate and the round-window (RW) membrane were (sequentially) measured by laser Doppler vibrometry. Vibration responses for coupling of an FMT to the long incus process (standard coupling) were compared to those for coupling to the short incus process.

RESULTS

Apart from narrow frequency bands near 3 and 9 kHz for the stapes footplate and RW membrane, respectively, the velocity responses presented no significant differences between standard coupling of the FMT and coupling to the short incus process.

CONCLUSION

Coupling the FMT to the short incus process may be a viable alternative in cases where the surgical approach is limited to an extended antrotomy. A reliable technique for attachment to the short incus process has yet to be developed.

Hearing rehabilitation with middle ear implants: an overview

Implant otology has been a rapidly growing field with growing needs and development Over a few decades. The introduction of middle ear implants in the last 2 decades has seen good short-term success in rehabilitation of patients with deafness ranging from mild to severe degree. Middle ear implants are alternatives to conventional hearing aids and bone anchored hearing aids; together these aids and implants provide patients with a range of available options in augmentation of hearing. This article describes the types of middle ear implants and their mechanism of action, the surgical and audio-logical criteria for implantation, their limitations and reported outcomes.

A surgical technique for implantation of the vibrant soundbridge middle ear implant in dogs

OBJECTIVE

To report a surgical implantation of the Vibrant Soundbridge (VSB) middle ear implant in dogs.

STUDY DESIGN

Pilot study.

ANIMALS

Dogs (n=3).

METHODS

A lateral approach to the tympanic bulla was used to insert the floating mass transducer of the VSB into the tympanic bulla. Using microscopic guidance the transducer was moved to and inserted into the round window niche by manipulation through the acoustic bony meatus, after reflection of the tympanic membrane. VSB position was confirmed by computed tomography (CT) imaging.

RESULTS

No intraoperative complications occurred and CT images confirmed correct placement of the VSB.

CONCLUSIONS

A VSB can be safely implanted in the middle of dogs.

Active middle ear implant compared with open-fit hearing aid in sloping high-frequency sensorineural hearing loss

OBJECTIVE

To compare 2 open-ear hearing solutions for sloping high-frequency sensorineural hearing loss: open-fit hearing aid (HA) and active middle ear implant (AMEI).

STUDY DESIGN

Within-subjects prospective design.

SETTING

Tertiary referral hospital. PATIENTS AND DEVICES: Fourteen patients with sloping, high-frequency sensorineural hearing loss were recruited from 39 patients previously implanted with an AMEI and 10 agreed to participate, ranging in age from 44 to 73 years (mean, 59 yr). Patients were selected because their hearing thresholds (500-3,000 Hz) qualified them for both AMEI and open-fit HA use. All patients received a Vibrant Soundbridge (Vibrant MED-EL) for an average of 25.1 months before data collection and used their AMEI on a daily basis. The open-fit HA used in this study was the Delta 8000 (Oticon). Both study devices have been fit with the specific fitting strategies as recommended by the manufacturer.

MAIN OUTCOME MEASURES

Sound-field hearing thresholds, Freiburger monosyllabic words in quiet, speech reception thresholds for 50% correct recognition for Freiburger numbers and for Oldenburg sentences in quiet, and speech reception thresholds for 50% correct recognition for Oldenburg sentences in noise.

RESULTS

Both HA and AMEI conditions showed significantly better sound-field thresholds and speech recognition on monosyllabic word and sentence tests in quiet and in noise than in the unaided condition. A comparison of aided conditions revealed that, in the AMEI-aided condition, high-frequency audibility and speech discrimination scores in quiet and in noise were significantly better than those in the open-fit HA.

CONCLUSION

Both open-fit HAs and AMEIs provided audiologic benefit to patients with sloping high-frequency sensorineural hearing loss. However, despite overlapping indication criteria for the 2 devices, performance with the AMEI was significantly better for the AMEI than for the open-fit HA.

Treatment of age-related hearing loss in dogs with the vibrant soundbridge middle ear implant: short-term results in 3 dogs

BACKGROUND

Age-related hearing loss (ARHL), or presbycusis, is the most common form of acquired hearing loss in dogs. Middle ear implants have been used successfully in people with ARHL who cannot benefit from conventional hearing aids.

HYPOTHESIS

Audibility improves in dogs with ARHL after implantation of the Vibrant Soundbridge (VSB) middle ear implant.

ANIMALS

Three Beagle dogs with ARHL, mean age 11.1 years.

METHODS

The dogs were assessed pre- and postoperatively by brainstem-evoked response audiometry (BERA), otoscopy, and computed tomography scans of the ears. A VSB middle ear implant was implanted unilaterally. Three months later the functionality of the implants was assessed by auditory steady-state responses (ASSRs), after which the dogs were euthanized for histopathological examination.

RESULTS

The VSB was implanted successfully in all dogs. Recovery from surgery was uneventful, except for transient facial nerve paralysis in 2 dogs. ASSRs showed that hearing improved after activation of the implants with a mean of 20.7, 13, and 16.3 dB at 1, 2, and 4 kHz, respectively. The implantation procedure did not affect residual hearing (with inactive implants) as measured by BERA.

CONCLUSIONS AND CLINICAL IMPORTANCE

Implantation of the VSB resulted in lower ASSR thresholds, but only at the higher gain settings of the audioprocessor. As in humans, a more powerful audioprocessor is required to treat sensorineural hearing loss exceeding 20 dB in dogs. A substantial improvement in patient-owner communication will have to be demonstrated in future studies before the procedure can be recommended in clinical practice.

[Rehabilitation of high frequency hearing loss: use of an active middle ear implant]

BACKGROUND

In spite of modern technology conventional hearing aids are only helpful in a limited number of patients with sensorineural hearing loss. In particular, patients presenting with moderate to severe high frequency hearing loss but only mild hearing loss in the low frequencies suffer from problems associated with conventional hearing aids such as occlusion of the ear canal and feedback. The aim of the study was the evaluation of rehabilitation of patients with high frequency hearing loss with the active middle ear implant Vibrant Soundbridge.

PATIENTS AND METHODS

The Vibrant Soundbridge was surgically implanted into 30 patients, and the floating mass transducer was clipped onto the long process of the incus. Out of the 30 patients 9 presented with a ski slope audiogram of high frequency hearing loss of 25 dB within 1 octave in the frequency range 1000-8000 Hz. Main outcome measures were pure tone audiometry, speech audiometry in quiet and in noise.

RESULTS

Residual hearing was preserved in all cases. Functional hearing gain was in proportion to the individual hearing losses and was remarkably high in the high frequencies up to 8000 Hz. Mean functional gain was 34 dB in the frequencies between 2000-8000 Hz. Speech recognition scores in quiet and in noise were significantly higher with the implant compared to the unaided situation.

CONCLUSION

The middle ear implant Vibrant Soundbridge has been shown to be perform extremely well especially in the high frequencies. It offers a new solution for rehabilitation of high frequency hearing loss.

Long-term assessment after implantation of the Vibrant Soundbridge device

OBJECTIVE

To present long-term results with a semi-implantable middle ear implant, the Vibrant Soundbridge (VSB), and analyze pre- and post-operative results of audiologic tests.

STUDY DESIGN

Retrospective chart review with additional patient interview and audiologic testing.

SETTING

One tertiary referral center.

SUBJECTS

Twenty patients who met the selection criteria of the manufacturer were evaluated at least two years after implantation.

INTERVENTIONS

Monaural Implantation of the VSB in 20 patients, in two of these 20 patients implantation of the second ear in a second stage.

RESULTS

Assessment of benefit and satisfaction using the standardized International Outcome Inventory for Hearing Aids, the Glasgow Benefit Inventory, and Visual Analogue Scales in all patients. Fifteen patients agreed to undergo audiologic testing at follow-up including pure-tone- and speech audiometry in silence and noise. The majority of patients (13/20) reported to be satisfied or very satisfied with the VSB. Aided speech perception was comparable between the VSB and the hearing aid preoperatively. When compared to the preoperative audiograms, residual hearing from 0.5-4 kHz was significantly worse in the operated ear with 8 dB (Wilcoxon signed rank test p < 0.001) but only 2.6 dB in the non-operated ear (Wilcoxon signed rank test, p > 0.05). Major surgical complications did not occur. Permanent alteration in taste occurred in three patients and revision surgery was necessary in another three patients.

CONCLUSION

Satisfaction with the VSB was not superior to conventional hearing aids in subjective and in audiometric terms. Because of its impact on residual hearing and the requirement of implantation middle ear surgery, implantation of the VSB should be limited to patients with relevant side effects of hearing aids, e.g., severe chronic otitis externa.

Minimal access surgery for the Symphonix/Med-El Vibrant Soundbridge middle ear hearing implant

OBJECTIVE

To develop a minimal access approach for implantation of the Vibrant Soundbridge middle ear hearing implant. This approach ideally uses the smallest skin incision possible, minimal or no hair shave, and the least possible amount of tissue and bone manipulation. This will facilitate the acceptability of the procedure to the general community and reduce the flap-related complication rate. The procedure is similar to the minimal access approach described for cochlear implantation.

STUDY DESIGN

Eight patients with various degrees of sensorineural hearing loss and one with a mixed hearing loss who met implant criteria for the Vibrant Soundbridge middle ear hearing implant received the device over a 42-month period. The first two patients underwent the traditional implant procedure with postauricular hair shave, postauricular S-shaped incision, and implant receiver suture fixation to the temporal bone. The following seven consecutive patients received a progressively smaller C-shaped postauricular skin incision, no hair shave, retrograde skull drilling for the implant seat, and no implant suture fixation until the technique closely approximated the minimal access cochlear implant procedure. Postoperative performance of the Soundbridge/Vibrant Med-El was evaluated through audiology testing and subjective patient reports.

SETTING

Private neurotology clinic and tertiary care teaching hospital.

RESULTS

The technique was feasible in all patients. Follow-up for the minimal access group ranged from 3 years to 5 months. There were no complications related to the approach, and all patients were satisfied users of the implant. The lack of hair shave and small incision size was greatly appreciated and warmly endorsed by the patients.

CONCLUSION

The Vibrant Soundbridge/Vibrant Med-El can be safely implanted using the minimal access method that has been popularized for cochlear implant surgery. A large incision, extensive hair shave, risk of flap necrosis, and possibility of unsightly scar may deter patients from pursuing the potential benefits of implanted hearing technology. The technique may make the device more accessible to individuals who have concerns regarding cosmetics and potential flap complications.

Fully Implantable Hearing Aids in Patients With Congenital Auricular Atresia

INTRODUCTION

Patients with congenital auricular atresia suffer from a conductive hearing loss (HL) with an air-bone gap of 50 to 60 dB. Conventional bone conducting or bone anchored hearing aids are treatment options with several disadvantages and a biophysical limitation of almost no sound attenuation in the skull bone. Surgical construction of the sound conducting apparatus has been performed by others and modified by us into a three-step procedure with in vivo prefabrication of the external ear canal and the tympanic membrane. Although the results improved after inauguration of our modifications, there still remains an air-bone gap that makes air conducting hearing aids necessary in many patients. Implantable hearing aids have been developed for patients with perceptional HL and normal middle ear function but not for patients with middle ear disease or malformation.

OBJECTIVES

Our objectives were to improve the hearing results of auricular atresia.

STUDY DESIGN

Prospective.

METHODS

The surgical instruments, the transducer, and the operative technique of the only fully implantable hearing aid (Otologics Fully Implantable Middle Ear Transducer) clinically available were modified. They were implanted in five patients with congenital auricular atresia and their audiologic outcome evaluated.

RESULTS

After activation and fitting of the devices, patients experienced an improvement of sound-field thresholds up to 50 dB HL. The mean functional gain in a three frequency pure-tone average was approximately 35 dB HL.

CONCLUSIONS

This technique appears to provide a completely new dimension for the audiologic rehabilitation of patients with severe malformation of the middle ear.

Magnetic Resonance Imaging Compatibility and Safety of the SOUNDTEC Direct System

OBJECTIVE/HYPOTHESIS

The purpose of this study was to evaluate magnetic resonance imaging (MRI) compatibility and safety of an electromagnetic implanted hearing device (the SOUNDTEC Direct System; SOUNDTEC, Inc., Oklahoma City, OK) implant during a 0.3-Tesla open MRI imaging examination of the head and neck and to develop an MRI protocol that maximizes patient safety while minimizing the need for implant removal. The current literature regarding MRI compatibility of implantable hearing devices was reviewed.

STUDY DESIGN

Linear and torsional forces, heating, and implant magnetization were evaluated in vitro. Implanted fresh-frozen human temporal bones were used to evaluate image distortion. A prospective study of 11 volunteers previously implanted with the SOUNDTEC Direct System was conducted to evaluate MRI compatibility and safety. A MEDLINE search of the literature between 1980 and July 2005 was reviewed to summarize MRI compatibility testing of implantable hearing devices.

METHODS

Torsional and linear forces experienced by eight implant magnets were measured using calibrated neurologic Von Frey Hairs and compared with finite element analysis predictions as well as forces required to separate the incudostapedial joints of 12 fresh-frozen human temporal bones. Implant heating was determined by measuring the temperature change of eight implant vials compared with saline controls immediately after a head MRI scan. Implant magnetization was evaluated after repeated exposure to a 0.3-Tesla magnetic field. An 11-patient prospective study was performed to evaluate MRI compatibility in a 0.3-Tesla open MRI environment using adult volunteers previously implanted with the SOUNDTEC Direct System. A modified MRI protocol was developed to maximize patient safety. Each individual underwent an audiometric and otologic examination immediately before and after MRI.

RESULTS

Peak linear force at the MRI entry measured 0.5 g +/- 0.2 standard deviation (SD). Maximum torque occurred at isocenter and measured 11.4 g-cm +/- 1.2 SD. The mean torque required to separate the incudostapedial joint was 33.8 g-cm +/- 20.4 SD. The average increase in temperature of the eight implant vials was 0.45 degrees C +/- 0.11 SD, whereas the increase in temperature of the three saline controls measured 0.47 degrees C +/- 0.11 SD. The average change in magnetic flux density of the 14 implant magnets tested was 22.0 gauss. Maximum image distortion occurred during the gradient echo sequence and measured 8.6 cm in diameter with a volume of 5,096 mm. Eleven patients completed a total of 12 head, one shoulder, and three lumbar 0.3-Tesla open MRI scans without patient- or device-related complications other than degradation of the MR image. There was no report of discomfort, tinnitus, dizziness, change in hearing, or change in device performance. All post-MRI changes in pure-tone thresholds, speech discrimination, soundfield thresholds, and aided soundfield thresholds were within the range of test-retest variability.

CONCLUSION

When considering MRI of implantable ferromagnetic hearing devices, issues related to mechanical forces, implant heating, current induction, implant demagnetization, image degradation, and acoustic trauma must be considered. The SOUNDTEC Direct System is both MRI-compatible and safe in a 0.3-Tesla open MRI environment when a modified protocol is used. Degradation of the head MRI image may impair visualization of the ipsilateral temporal bone and adjacent structures within a 2.5- to 4.3-cm radius of the implant and is minimized by using a fast spin echo sequence.

The Effects of Mass Loading the Ossicles with a Floating Mass Transducer on Middle Ear Transfer Function

HYPOTHESIS

The aim of this study was to measure the mass loading effect of an active middle-ear implant (the Vibrant Soundbridge) in cadaver temporal bones.

BACKGROUND

Implantable middle ear hearing devices such as Vibrant Soundbridge have been used as an alternative to conventional hearing aids for the rehabilitation of sensorineural hearing loss. Other than the obvious disadvantage of requiring implantation middle ear surgery, it also applies a direct weight on the ossicular chain which, in turn, may have an impact on residual hearing. Previous studies have shown that applying a mass directly on the ossicular chain has a damping effect on its response to sound. However, little has been done to investigate the magnitude and the frequency characteristics of the mass loading effect in devices such as the Vibrant Soundbridge.

METHODS

Five fresh cadaver temporal bones were used. The stapes displacement was measured using laser Doppler vibrometry before and after the placement of a Vibrant Soundbridge floating mass transducer. The effects of mass and attachment site were compared with the unloaded response. Measurements were obtained at frequencies between 0.1 and 10 kHz and at acoustic input levels of 100 dB sound pressure level. Each temporal bone acted as its own control.

RESULTS

Placement of the floating mass transducer caused a reduction of the stapes displacement. There were variations between the bones. The change of the stapes displacement varied from 0 dB to 28 dB. The effect was more prominent at frequencies above 1,000 Hz. Placing the floating mass transducer close to the incudostapedial joint reduced the mass loading effect.

CONCLUSION

The floating mass transducer produces a measurable reduction of the stapes displacement in the temporal bone model. The effect is more prominent at high frequencies.

Comparison of the implantability of electronic hearing devices in a virtual reality planning environment and in human temporal bones

OBJECTIVE

To develop a procedure using a virtual reality (VR) environment that permitted us to simulate the preoperative fitting of an electronic implantable hearing device (IHD) and assess its implantability.

MATERIAL AND METHODS

This was an experimental, prospective study based on VR simulations involving the pre- and postoperative comparison of the implantability of an IHD. The preoperative possibility of implanting an IHD in a VR environment was compared with the postoperative implantability of the device in the temporal bones of human cadavers and patients. Study groups were analyzed according to the criteria "VR implantation" and "real surgery" using contingency tables.

RESULTS

A computer simulation method based on CT images was developed for the preoperative planning of the implantation. The VR simulation proved feasible in all cases (15 temporal bones and 24 patients). There was no significant difference between the process of implanting the IHD in patients or in the VR environment. These results indicate that VR-based test fittings of an IHD allow prediction of the implantability of an IHD prior to actual surgery.

CONCLUSION

We have described the development of a novel VR procedure for predicting the implantability of hearing devices in otoneurosurgical applications. The VR procedure can be applied universally and may also be used for other parts of the body.

Audiometric evaluation of an attempt to optimize the fixation of the transducer of a middle-ear implant to the ossicular chain with bone cement

Typically, an implantable hearing device consists of a transducer that is coupled to the ossicular chain and electronics. The coupling is of major importance. The Vibrant Soundbridge (VSB) is such an implantable device; normally, the VSB transducer is fixed to the ossicular chain by means of a special clip that is crimped around the long process of the incus. In addition to crimping, bone cement was used to optimize the fixation in six patients. Long-term results were compared to those of five controls with crimp fixation alone. To assess the effect of bone cement (SerenoCem, Corinthian Medical Ltd, Nottingham, UK) on hearing thresholds, long-term post-surgery thresholds were compared to pre-surgery thresholds. Bone cement did not have any negative effect. Next, to test the hypothesis that aided thresholds might be better with the use of bone cement, aided thresholds were studied. After correction for the severity of hearing loss, only a small difference was found between the two groups at one frequency, viz. 2 kHz. It was concluded that there was no negative effect of using bone cement; however, there is also no reason to use bone cement in VSB users on a regular basis.

In vivo characterization of piezoelectric transducers for implantable hearing AIDS

BACKGROUND

Piezoelectric bimorph transducers may be used at the input stage of implantable hearing aids to convert ossicle vibrations into electrical waveforms, and at the output stage to convert electrical signals into mechanical motion that drives the ossicles. This study assessed transducer performance in anesthetized, acutely implanted cats using computer-averaged, laser-Doppler vibrometer measures and cochlear potentials.

METHODS

Measures of output linearity and distortion for a transducer placed on the umbo were obtained from averaged laser-Doppler vibrometer outputs. Frequency response and equivalent sound pressure level for transducers placed against the stapes were estimated by comparing compound action potentials and cochlear microphonics elicited preoperatively by acoustic signals with responses elicited postoperatively by signals presented through transducers.

RESULTS

The transducer placed on the umbo exhibited an effective bandwidth that exceeded 8 kHz, linear response behavior for driving voltages up to 2 Vrms, and harmonic distortion of -40 dB or better at all frequencies greater than 250 Hz. Except for a shorter latency, transducer-elicited cochlear potentials were indistinguishable from acoustically elicited responses. Frequency response varied widely across transducers, ranging from reasonably flat to possessing a bandpass characteristic with a peak at 2 to 4 kHz; 1-Vrms signals applied to transducers with various geometries yielded equivalent intensities of 62 to 108 dB sound pressure level at 4 kHz, 51 to 98 dB sound pressure level at 2 kHz, and 55 to 80 dB sound pressure level at 1 kHz. Differences in frequency response and equivalent sound pressure level stemmed from different resonance frequencies in transducers with dissimilar lengths and, more importantly, from variation in transducer-stapes contact force.

CONCLUSIONS

Appropriately designed piezoelectric transducers can provide the cochlea with high-fidelity, wide-bandwidth signals. However, using them in implantable hearing aids requires that geometry and contact force be optimized to reduce variability in output level. Recording cochlear potentials is a cost-effective means of assessing transducer performance intraoperatively, but care must be exercised to take into account any temporary, drill-induced sensitivity loss.

Rehabilitation for high-frequency sensorineural hearing impairment in adults with the symphonix vibrant soundbridge: a comparative study

OBJECTIVE

To assess and compare the benefits for patients with high-frequency hearing loss obtained from an implantable middle ear implant, the Symphonix Vibrant Soundbridge using the SIGNIA processing circuitry, to those derived from conventional amplification using the same integrated circuitry and to those derived from a variety of preoperatively worn hearing aids.

STUDY DESIGN

A single-subject, repeated-measures study design was used for a comparative evaluation of the benefits derived from the Symphonix Vibrant Soundbridge and conventional amplification. Objective audiometric measures were performed postoperatively to compare the Symphonix Vibrant Soundbridge (404) and SIGNIA hearing aid, both using the SIGNIA processing chip. Tests were performed under three conditions: unaided, aided Symphonix Vibrant Soundbridge (404), and aided SIGNIA hearing aid. Subjective self-assessment scales, standardized and nonstandardized, were completed for the Symphonix Vibrant Soundbridge (404) and the preoperative hearing aid to compare the personally perceived benefits. Statistical comparison of the data sets with each device type was performed using the nonparametric Wilcoxon test.

SETTING

One tertiary teaching hospital and one hearing aid specialist fitting office.

SUBJECTS

Six patients displaying a high-frequency hearing loss who had the Symphonix Vibrant Soundbridge implanted for an average of 17 months.

INTERVENTION

Rehabilitative.

RESULTS

Aided thresholds with the Symphonix Vibrant Soundbridge (404) and the SIGNIA hearing aid showed no significant difference. Speech comprehension scores in quiet and in noise were significantly improved with each device type over the unaided condition scores. Individual performance on speech test measures was equivalent or superior with the Symphonix Vibrant Soundbridge (404) in comparison with that with the SIGNIA hearing aid. When using the Symphonix Vibrant Soundbridge (404) in quiet, the group achieved 50% speech comprehension at significantly softer presentation levels (p = 0.027) than when wearing the SIGNIA hearing aid. Similarly, in noise, 50% speech comprehension was achieved at significantly lower (more difficult) signal-to-noise ratios (p = 0.028) with the Symphonix Vibrant Soundbridge (404) than with the SIGNIA hearing aid. The level of satisfaction for various aspects of the device and performance and listening ease, particularly in the presence of aversive sounds and in reverberant conditions, was reported as significantly better with the Symphonix Vibrant Soundbridge (404) than with the preoperative hearing aid.

CONCLUSIONS

Despite similar gain with each device type using the same SIGNIA processing technology, the patient group demonstrated significant advantages for speech comprehension in quiet and in noise when using the Symphonix Vibrant Soundbridge (404). Such an effect may be attributed to higher fidelity sound transmission by means of the direct-drive mechanism used by the implant. Subjective reports support the results from the objective assessments, both being in favor of the implant over conventional amplification. In conclusion, the Symphonix Vibrant Soundbridge (404) is a suitable treatment option offering advantages over conventional amplification to the hearing-impaired person with a high-frequency hearing loss.

A middle ear implant, the Symphonix Vibrant Soundbridge: retrospective study of the first 125 patients implanted in France

OBJECTIVE

The Vibrant Soundbridge is an active semi-implantable middle ear implant for the rehabilitation of patients with a sensorineural hearing loss who are not able to derive adequate benefit from conventional hearing aids. A retrospective study was performed to assess the overall level of satisfaction of implanted patients and to investigate the potential determinants of postoperative success.

STUDY DESIGN

A retrospective survey of audiological data from repeated measures and subjective data from self-assessment scales administered postoperatively was conducted to determine the degree of benefit and satisfaction for Vibrant Soundbridge implantees.

SETTING

Twenty-one tertiary referral and teaching hospitals.

SUBJECTS

The first 125 VSB implantees implanted in France between August 1997 and May 2001 were included in the study.

RESULTS

No clinically significant change was observed for residual hearing postoperatively. Most patients (83%) reported they were either satisfied or very satisfied with the Vibrant Soundbridge. Analysis of correlation revealed a moderate correlation (Pearson coefficient r = 0.59) between the degree of benefit reported via the patient survey and the degree of benefit reported via the Glasgow Benefit Inventory. A moderate correlation (Pearson coefficient r = 0.66) was observed between speech comprehension scores in quiet for the preoperative unaided condition and the postoperative aided Vibrant Soundbridge condition. No correlation was observed between subjective reports of satisfaction postoperatively and performance on preoperative objective tests or patient characteristics.

CONCLUSION

The results indicate a high level of satisfaction with the VSB as a treatment of sensorineural hearing impairment in patients with a wide range of characteristics. Preoperative scores for unaided speech comprehension tests in quiet may be a potential indicator of success on aided Vibrant Soundbridge speech comprehension tests postoperatively but do not reflect patient satisfaction with the device reported on self-assessment scales.

Medical and surgical considerations for implantable hearing prosthetic devices

Today, technology allows us the opportunity to make a substantial difference in the quality of life for individuals who have been unsuccessful with traditional amplification. This article examines the medical and surgical aspects of four types of implantable hearing devices: bone-anchored hearing aid (BAHA), middle ear implants, cochlear implants, and auditory brainstem implants.

Biomechanical influences of magnetic resonance imaging on the SOUNDTEC Direct System implant

OBJECTIVE

The purpose of this study was to measure the forces experienced by the SOUNDTEC Direct System magnetic implant during 0.3-T MRI.

STUDY DESIGN

Torsional and linear forces imposed on 8 implants were measured by using calibrated neurologic Von Frey hairs and were compared with finite-element analysis predictions and the forces required to separate the incudostapedial joints of unpreserved temporal bones. An implanted embalmed autopsy specimen was also examined before and after 1.5-T MRI.

RESULTS

Peak linear force at the orifice of the MRI core measured 0.51g (+/-0.2 SD). Maximum torque occurred at the MRI core center and measured 11.4g-cm (+/-1.2 SD). The mean torque required to separate the incudostapedial joints of 12 unpreserved temporal bones was 33.8g-cm (+/-20.4 SD). The autopsy specimen sustained a 1.5-T MRI scan without disruption of the ossicular chain or explantation.

CONCLUSIONS

Physical and mechanical testing of the SOUNDTEC implant indicates that the structural integrity of the ossicles will be maintained during 0.3-T MRI of the human head.