Long-Term, Multicenter Results With the First Transcutaneous Bone Conduction Implant

Magnetic Resonance Imaging Artifact Associated With Transcutaneous Bone Conduction Implants: Cholesteatoma and Vestibular Schwannoma Surveillance

OBJECTIVE

To evaluate the magnetic resonance (MR) image artifact and image distortion associated with the two transcutaneous bone conduction implants currently available in the United States.

STUDY DESIGN

Cadaveric study.

METHODS

Two cadaveric head specimens (1 male, 1 female) were unilaterally implanted according to manufacturer guidelines and underwent MR imaging (General Electric and Siemens 1.5 T scanners) under the following device conditions: (1) no device, (2) Cochlear Osia with magnet and headwrap, (3) Cochlear Osia without magnet, and (4) MED-EL Bonebridge with magnet. Maximum metal mitigation techniques were employed in all conditions, and identical sequences were obtained. Blinded image scoring (diagnostic vs nondiagnostic image) was performed by experienced neuroradiologists according to anatomical subsites.

RESULTS

All device conditions produced artifact and image distortion. The Osia with magnet produced diagnostic T1- and T2-weighted images of the ipsilateral temporal bone, however, non-echo planar imaging diffusion-weighted imaging (DWI) was nondiagnostic. The Osia without magnet scanned on the Siemens MR imaging demonstrated the least amount of artifact and was the only condition that allowed for diagnostic imaging of the ipsilateral temporal bone on DWI. The Bonebridge produced a large area of artifact and distortion with the involvement of the ipsilateral and contralateral temporal bones.

CONCLUSION

In summary, of the three device conditions (Osia with magnet, Osia without magnet, and Bonebridge), Osia without magnet offered the least amount of artifact and distortion and was the only condition in which diagnostic DWI was available for the middle ear and mastoid regions on the Siemens MR imaging scanner.

Long-Term Follow-Up in Active Transcutaneous Bone Conduction Implants

OBJECTIVE

To evaluate long-term outcomes of active transcutaneous bone conduction implants (atBCIs) regarding safety, hearing, and quality of life.

STUDY DESIGN

A clinical study with retrospective medical record analysis combined with prospective audiometry and quality of life questionnaires.

SETTING

Three secondary to tertiary care hospitals.

PATIENTS

All subjects operated with an atBCI in three regions in Sweden were asked for informed consent. Indications for atBCI were single-sided deafness (SSD) and conductive or mixed hearing loss (CMHL).

INTERVENTION

Evaluation of atBCI.

MAIN OUTCOME MEASURES

Pure tone and speech audiometry and Glasgow Benefit Inventory (GBI).

RESULT

Thirty-three subjects were included and 29 completed all parts. The total follow-up time was 124.1 subject-years. Nineteen subjects had CMHL and in this group, pure tone averages (PTA4) were 56.6 dB HL unaided and 29.6 dB HL aided, comparable with a functional gain of 26.0 dB. Effective gain (EG) was -12.7 dB. With bilateral hearing, Word Recognition Scores (WRS) in noise were 36.5% unaided and 59.1% aided. Fourteen subjects had SSD or asymmetric hearing loss (AHL) and in this group, PTA4 were >100 dB HL unaided and 32.1 dB HL aided with the contralateral ear blocked. EG was -9.1 dB. With bilateral hearing, WRSs were 53.2% unaided and 67.9% aided. The means of the total GBI scores were 31.7 for CMHL and 23.6 for SSD/AHL.

CONCLUSION

Few complications occurred during the study. The atBCI is concluded to provide a safe and effective long-term hearing rehabilitation.

Experience With the New Active Transcutaneous Bone-Conduction Implant With Smaller Dimensions

OBJECTIVE

Recently, the Bonebridge 602 implant was introduced. Its smaller dimensions facilitate implantation even in surgically demanding cases. However, in extreme anatomical conditions, implant lifts are still required. We intended to report on the medical and audiological outcomes of all patients implanted with the implant with a secondary focus on the safety, efficacy, and feasibility of the use of 1-mm lifts.

STUDY DESIGN

Retrospective cohort study.

SETTING

Tertiary academic center.

METHODS

We retrospectively analyzed all patients implanted with the Bonebridge 602. Patient demographics and surgically-specific data were collected from the medical charts. Furthermore, audiological results were assessed. Outcomes were compared between implantations with versus without lifts.

RESULTS

Twenty-one devices were implanted during the study period. Satisfactory audiological results were observed, while no intra- or postoperative adverse events occurred. The majority of patients were daily users at the end of the observation period (n = 20/21, 95.2%), and one patient (n = 1/21, 4.8%) was a nonuser after 6 months of use because of subjective dissatisfaction. Due to anatomical considerations, 1-mm lifts were used in 4 implantations (19.0%). The application of lifts did not result in prolonged surgical times, complications, or shorter time of use, nor did it negatively affect audiometric results.

CONCLUSION

Implantations with the new and smaller Bonebridge were associated with gratifying medical and audiological outcomes. Still, in extreme anatomical conditions, 1-mm lifts are necessary. Nonetheless, surgical placement with the help of lifts seems safe, effective, and feasible, and is a viable option in cases with challenging anatomies due to previous surgeries or anomalies.

A bone conduction implant using self-drilling screws : Self-drilling screws as a new fixation method of an active transcutaneous bone conduction hearing implant

BACKGROUND

The active transcutaneous bone conduction implant (tBCI; BONEBRIDGE™ BCI 601; MED-EL, Innsbruck, Austria) is fixed to the skull with two self-tapping screws in predrilled screw channels. The aim of this prospective study was to evaluate the safety and effectiveness of fixation with self-drilling screws instead of the self-tapping screws, in order to simplify the surgical procedure.

MATERIALS AND METHODS

Nine patients (mean age 37 ± 16 years, range 14-57 years) were examined pre- and 12 months postoperatively for word recognition scores (WRS) at 65 dB SPL, sound-field (SF) thresholds, bone conduction thresholds (BC), health-related quality of life (Assessment of Quality of Life, AQOL-8D questionnaire), and adverse events (AE).

RESULTS

Due to avoidance of one surgical step, the surgical technique was simplified. Mean WRS in SF was 11.1 ± 22.2% (range 0-55%) pre- and 77.2 ± 19.9% (range 30-95%) postoperatively; mean SF threshold (pure tone audiometry, PTA4) improved from 61.2 ± 14.3 dB HL (range 37.0-75.3 dB HL) to 31.9 ± 7.2 dB HL (range 22.8-45.0 dB HL); mean BC thresholds were constant at 16.7 ± 6.8 dB HL (range 6.3-27.5 dB HL) pre- and 14.2 ± 6.2 dB HL (range 5.8-23.8 dB HL) postoperatively. AQOL-8D mean utility score increased from 0.65 ± 0.18 preoperatively to 0.82 ± 0.17 postoperatively. No device-related adverse events occurred.

CONCLUSION

Implant fixation by means of self-drilling screws was safe and effective in all nine patients. There was significant audiological benefit 12 months after implantation.

[Transcutaneous bone conduction implant with self-drilling screws : A new method for fixation of an active transcutaneous bone conduction implant. German version]

BACKGROUND

The active transcutaneous bone conduction implant (tBCI; BONEBRIDGE™ BCI 601; MED-EL, Innsbruck, Austria) is fixed to the skull with two self-tapping screws in predrilled screw channels. The aim of this prospective study was to evaluate the safety and effectiveness of fixation with self-drilling screws instead of the self-tapping screws, in order to simplify the surgical procedure.

MATERIALS AND METHODS

Nine patients (mean age 37 ± 16 years, range 14-57 years) were examined pre- and 12 months postoperatively for word recognition scores (WRS) at 65 dB SPL, sound-field (SF) thresholds, bone conduction thresholds (BC), health-related quality of life (Assessment of Quality of Life, AQOL-8D questionnaire), and adverse events (AE).

RESULTS

Due to avoidance of one surgical step, the surgical technique was simplified. Mean WRS in SF was 11.1 ± 22.2% (range 0-55%) pre- and 77.2 ± 19.9% (range 30-95%) postoperatively; mean SF threshold (pure tone audiometry, PTA₄) improved from 61.2 ± 14.3 dB HL (range 37.0-75.3 dB HL) to 31.9 ± 7.2 dB HL (range 22.8-45.0 dB HL); mean BC thresholds were constant at 16.7 ± 6.8 dB HL (range 6.3-27.5 dB HL) pre- and 14.2 ± 6.2 dB HL (range 5.8-23.8 dB HL) postoperatively. AQOL-8D mean utility score increased from 0.65 ± 0.18 preoperatively to 0.82 ± 0.17 postoperatively. No device-related adverse events occurred.

CONCLUSION

Implant fixation by means of self-drilling screws was safe and effective in all nine patients. There was significant audiological benefit 12 months after implantation.

Multicentric study on surgical information and early safety and performance results with the Bonebridge BCI 602: an active transcutaneous bone conduction hearing implant

AIM

This European multicentric study aimed to prove safety and performance of the Bonebridge BCI 602 in children and adults suffering from either conductive hearing loss (CHL), mixed hearing loss (MHL), or single-sided sensorineural deafness (SSD).

METHODS

33 patients (13 adults and 10 children with either CHL or MHL and 10 patients with SSD) in three study groups were included. Patients were their own controls (single-subject repeated measures), comparing the unaided or pre-operative to the 3-month post-operative outcomes. Performance was evaluated by sound field thresholds (SF), word recognition scores (WRS) and/or speech reception thresholds in quiet (SRT) and in noise (SNR). Safety was demonstrated with a device-specific surgical questionnaire, adverse event reporting and stable pure-tone measurements.

RESULTS

The Bonebridge BCI 602 significantly improved SF thresholds (+ 25.5 dB CHL/MHL/SSD), speech intelligibility in WRS (+ 68.0% CHL/MHL) and SRT in quiet (- 16.5 dB C/MHL) and in noise (- 3.51 dB SNR SSD). Air conduction (AC) and bone conduction (BC) thresholds remained stable over time. All adverse events were resolved, with none unanticipated. Mean audio processor wearing times in hours [h] per day for the CHL/MHL group were ~ 13 h for adults, ~ 11 h for paediatrics and ~ 6 h for the SSD group. The average surgical length was 57 min for the CHL/MHL group and 42 min for the SSD group. The versatility of the BCI 602 (reduced drilling depth and ability to bend the transition for optimal placement) allows for treatment of normal, pre-operated and malformed anatomies. All audiological endpoints were reached.

CONCLUSIONS

The Bonebridge BCI 602 significantly improved hearing thresholds and speech understanding. Since implant placement follows the patient's anatomy instead of the shape of the device and the duration of surgery is shorter than with its predecessor, implantation is easier with the BCI 602. Performance and safety were proven for adults and children as well as for the CHL/MHL and SSD indications 3 months post-operatively.

An objective bone conduction verification tool using a piezoelectric thin-film force transducer

All hearing aid fittings should be validated with appropriate outcome measurements, whereas there is a lack of well-designed objective verification methods for bone conduction (BC) hearing aids, compared to the real-ear measurement for air conduction hearing aids. This study aims to develop a new objective verification method for BC hearing aids by placing a piezoelectric thin-film force transducer between the BC transducer and the stimulation position. The newly proposed method was compared with the ear canal method and the artificial mastoid method through audibility estimation. The audibility estimation adopted the responses from the transducers that correspond to the individual BC hearing thresholds and three different input levels of pink noise. Twenty hearing-impaired (HI) subjects without prior experience with hearing aids were recruited for this study. The measurement and analysis results showed that the force transducer and ear canal methods almost yielded consistent results, while the artificial mastoid method exhibited significant differences from these two methods. The proposed force transducer method showed a lower noise level and was less affected by the sound field signal when compared with other methods. This indicates that it is promising to utilize a piezoelectric thin-film force transducer as an in-situ objective measurement method of BC stimulation.

The Functional Hearing Gain with an Active Transcutaneous Bone Conduction Implant Does Not Correlate with the Subjective Hearing Performance

The functional hearing outcome with hearing implants does not always properly reflect the subjective benefit in everyday listening situations. In this study, the functional hearing gain and the impact on the subjective hearing ability and quality of life were assessed in patients with a Bonebridge. A chart review was performed on 45 patients with a Bonebridge who were provided with questionnaires regarding the hearing quality and health-related quality of life during their last clinical visit. The questionnaires consisted of the Speech, Spatial and Qualities (SSQ) and the Health Utility Index Mark 3 (HUI3). Eleven patients had to be excluded due to missing data. A total of 34 patients (37 ears) were included in the study. Aided hearing thresholds were significantly lower compared with the unaided condition, with a mean functional gain of 26.87 dB for patients with mixed/conductive hearing loss (MHL/CHL). Although patients with single-sided deafness (SSD) scored slightly lower on the SSQ compared with patients with MHL/CHL, all included patients reported improved subjective hearing quality with the BB compared with the hearing situation before implantation. No correlation was found between the functional hearing gain and the subdomains of the SSQ. SSD patients scored the HUI3 subdomain “hearing” slightly lower compared with MHL/CHL patients. Although not significant, a relationship was found between the functional gain and the “hearing” subdomain. No correlation was found for the other subdomains of the HUI3. Audiological measurements showed significantly improved hearing thresholds with the Bonebridge. Most importantly, the subjective benefit achieved in everyday listening situations was superior compared with the previous hearing condition. The lack of correlation between subjective questionnaire results and the functional hearing gain shows the importance of assessing both audiological and subjective hearing quality parameters in clinical routine.

The bone conduction implant BONEBRIDGE increases quality of life and social life satisfaction

PURPOSE

Transcutaneous active bone conduction hearing aids represent an alternative approach to middle ear surgery and conventional hearing aids for patients with conductive or mixed hearing loss. The aim of this study was to determine quality of life, subjective hearing experience and patients' satisfaction after implantation of a bone conduction hearing aid.

METHODS

This monocentric and retrospective study included twelve adult patients who received a bone conduction hearing aid (Bonebridge, MedEL) consisting of an extracorporeal audio processor and a bone conduction implant (BCI) between 2013 and 2017. On average 40 months after implantation, the patients were asked to answer three questionnaires regarding quality of life (AqoL-8D), self-reported auditory disability (SSQ-12-B) and user's satisfaction (APSQ) after implantation of the Bonebridge (BB). A descriptive statistical analysis of the questionnaires followed.

RESULTS

12 patients aged 26-85 years (sex: m = 7, w = 5) were recruited. The quality of life of all patients after implantation of the BB (AqoL 8D) averaged an overall utility score of 0.76 (SD ± 0.17). The mean for 'speech hearing' in the SSQ-12-B was + 2.43 (SD ± 2.03), + 1.94 (SD ± 1.48) for 'spatial hearing' and + 2.28 (SD ± 2.32) for 'qualities of hearing'. 11 out of 12 patients reported an improvement in their overall hearing. The APSQ score for the subsection 'wearing comfort' was 3.50 (SD ± 0.87), 'social life' attained a mean of 4.17 (SD ± 1.06). The 'device inconveniences' reached 4.02 (SD ± 0.71) and 'usability' of the device was measured at 4.23 (SD ± 1.06). The average wearing time of the audio processor in the cohort was 11 h per day, with 8 of 12 patients reporting the maximum length of 12 h per day.

CONCLUSION

BB implantation results in a gain in the perceived quality of life (AqoL 8D). The SSQ-12-B shows an improvement in subjective hearing. According to the APSQ, it can be assumed that the BB audio processor, although in an extracorporeal position, is rated as a useful instrument with positive impact on social life. The majority stated that they had subjectively benefited from BB implantation and that there were no significant physical or sensory limitations after implantation.

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.