Multicenter Clinical Investigation of a New Active Osseointegrated Steady-State Implant System.

OBJECTIVE: A new active transcutaneous bone conduction hearing implant system that uses piezoelectric technology has been developed: an active osseointegrated steady-state implant system (OSI). This was the first clinical investigation undertaken to demonstrate clinical performance, safety, and benefit of the new implant system. STUDY DESIGN AND SETTING: A multicenter prospective within-subject clinical investigation was conducted. PATIENTS: Fifty-one adult subjects with mixed and conductive hearing loss (MHL/CHL, n = 37) and single-sided sensorineural deafness (SSD, n = 14) were included. MAIN OUTCOME MEASURE: Audiological evaluations included audiometric thresholds, speech recognition in noise, and quiet. Hearing and health-related patient-reported outcomes (PROs; health utilities index [HUI], abbreviated profile of hearing aid benefit [APHAB], and speech, spatial of qualities of hearing scale [SSQ]), daily use, surgical and safety parameters were collected. RESULTS: Intra- and postoperative complications were few. One implant was removed before activation due to post-surgical infection. Compared with the preoperative softband tests, a significant improvement in speech recognition-in-noise was observed in the MHL/CHL group (-7.3 dB, p ≤ 0.0001) and the SSD group (-8.1 dB, p = 0.0008). In quiet, word recognition improved in the MHL/CHL group, most markedly at lower intensity input of 50 dB SPL (26.7%, p ≤ 0.0001). The results of all PROs showed a significant improvement with the new device compared with preoperative softband in the MHL/CHL group. In the SSD group significant improvements were observed in the APHAB and SSQ questionnaires. DISCUSSION: The results confirmed the clinical safety, performance, and benefit of this new treatment modality for subjects with CHL, MHL, and SSD.

A Multinational Cost-Consequence Analysis of a Bone Conduction Hearing Implant System-A Randomized Trial of a Conventional vs. a Less Invasive Treatment With New Abutment Technology.

Background: It is hypothesized that, for patients with hearing loss, surgically placing an implant/abutment combination whilst leaving the subcutaneous tissues intact will improve cosmetic and clinical results, increase quality of life (QoL) for the patient, and reduce medical costs. Here, incremental costs and consequences associated with soft tissue preservation surgery with a hydroxyapatite (HA)-coated abutment (test) were compared with the conventional approach, soft tissue reduction surgery with an all-titanium abutment (control). Methods: A cost-consequence analysis was performed based on data gathered over a period of 3 years in an open randomized (1:1) controlled trial (RCT) running in four European countries (The Netherlands, Spain, France, and Sweden). Subjects with conductive or mixed hearing loss or single-sided sensorineural deafness were included. Results: During the first year, in the Netherlands (NL), France (FR), and Spain (ES) a net cost saving was achieved in favor of the test intervention because of a lower cost associated with surgery time and adverse event treatments [NL €86 (CI -50.33; 219.20), FR €134 (CI -3.63; 261.30), ES €178 (CI 34.12; 97.48)]. In Sweden (SE), the HA-coated abutment was more expensive than the conventional abutment, which neutralized the cost savings and led to a negative cost (SE €-29 CI -160.27; 97.48) of the new treatment modality. After 3 years, the mean cost saving reduced to €17 (CI -191.80; 213.30) in the Netherlands, in Spain to €84.50 (CI -117.90; 289.50), and in France to €80 (CI -99.40; 248.50). The mean additional cost in Sweden increased to €-116 (CI -326.90; 68.10). The consequences in terms of the subjective audiological benefit and Health-related quality of life (HRQoL) were comparable between treatments. A trend was identified for favorable results in the test group for some consequences and statistical significance is achieved for the cosmetic outcome as assessed by the clinician. Conclusions: From this multinational cost-consequence analysis it can be discerned that health care systems can achieve a cost saving during the first year that regresses after 3 years, by implementing soft tissue preservation surgery with a HA-coated abutment in comparison to the conventional treatment. The cosmetic results are better. (sponsored by Cochlear Bone Anchored Solutions AB; Clinical and health economic evaluation with a new Baha® abutment design combined with a minimally invasive surgical technique, ClinicalTrials.gov NCT01796236).

Results of a 2-Year Prospective Multicenter Study Evaluating Long-term Audiological and Clinical Outcomes of a Transcutaneous Implant for Bone Conduction Hearing.

OBJECTIVE(S): To evaluate 2-year audiological and clinical outcomes of a transcutaneous implant for bone conduction hearing of a previously published 6-month evaluation. DESIGN: Fifty-four unilaterally implanted adult patients with conductive or mild mixed hearing loss or single-sided sensorineural deafness were included in this prospective multicenter study. Follow-up visits were scheduled post-surgery at 10 days; 4, 6, and 12 weeks; 6, 12, and 24 months. Main outcomes were audiological benefit, patient-reported outcomes (PROs), soft tissue status, pain, numbness, implant survival, and daily usage. RESULTS: In the study population, the transcutaneous implant resulted in statistically significant improvement in objective hearing test and PROs compared with the unaided situation. Soft tissue complications were observed in 4.6% of the patients per visit. Pain/discomfort and numbness were initially reported in the majority of the patients, but declined over time; approximately 9% of patients reported some degree of numbness and 15% (slight) pain/discomfort after 2 years. During the 24-month period, two implant magnets were removed (3.7%), while two other implants were converted to the percutaneous counterpart (3.7%). At the final visit, 89.6% (n = 42 out of 47) of the patients used their sound processor, with a median daily usage of 6 h/d (range, 0-18 h/d). CONCLUSIONS: After 24 months, the transcutaneous implant provided statistically significant mean improvement in objective and subjective hearing performance as well as PROs compared with the preoperative unaided condition and had a low soft tissue complication rate. The test device could be considered as an alternative treatment option for appropriately selected and counseled patients.

Audiological and clinical outcomes of a transcutaneous bone conduction hearing implant: Six-month results from a multicentre study.

OBJECTIVES: To compare the hearing performance of patients with conductive and mild mixed hearing loss and single-sided sensorineural deafness provided with a new transcutaneous bone conduction hearing implant (the Baha Attract System) with unaided hearing as well as aided with a sound processor on a softband. Furthermore, to evaluate safety and subjective benefit before and after implantation of the test device. PARTICIPANTS: Fifty-four adult patients in five participating centres were enrolled in this prospective study. Baseline data were collected during a pre-operative visit, and after a softband trial, all patients were implanted unilaterally. Follow-up visits were scheduled at 10 days, 4, 6, 12 weeks and 6 months. MAIN OUTCOME MEASURES: Free-field hearing thresholds pure-tone average (PTA4 in dB HL; mean threshold at 500, 1000, 2000, 4000 Hz; primary outcome measure). Individual free-field hearing thresholds, speech recognition in quiet and in noise, soft tissue status during follow-up and subjective benefit as measured with the Abbreviated Profile of Hearing Aid Benefit (APHAB), Speech, Spatial and Qualities of Hearing Scale (SSQ) and Health Utilities Index (HUI) questionnaires. RESULTS: Implantation of the Baha Attract System resulted in favourable audiological outcomes compared to unaided conditions. On the primary outcome parameter, a statistically significant improvement was observed compared to unaided hearing for the patients with conductive/mixed hearing loss (mean PTA4 difference -20.8 dB HL, SD 9.8; P < 0.0001) and for the patients with single-sided sensorineural deafness (SSD) (mean PTA4 difference -21.6 dB HL, SD 12.2; P < 0.0001). During all audiology tests, the non-test ear was blocked. Statistically significant improvements were also recorded in speech tests in quiet and noise compared to unaided hearing for the conductive/mixed hearing loss group and for speech in quiet in the SSD group. Compared to the pre-operative measurement with softband, no significant differences were recorded in the PTA4 free-field hearing threshold or the other audiological outcomes in either of the groups (P > 0.05). Soft tissue-related issues observed during follow-up included numbness, pain/discomfort at the implant site and to a lesser extent pressure-related skin complications. A declining trend was noted in the rate of these complications during follow-up. Approximately 20% of patients reported some degree of numbness and 38% (slight) pain/discomfort at final follow-up of 6 months. Good results on the subjective benefit questionnaires were observed, with statistically significant improvements on APHAB and SSQ questionnaires, and on the hearing attribute of HUI3. CONCLUSIONS: The Baha Attract System provided a significant improvement in hearing performance and subjective benefit compared to the pre-operative unaided condition (with the non-test ear blocked). Hearing performance of the Baha Attract was similar to a test situation with the same sound processor on a softband. A proportion of the patients reported numbness and pain/discomfort at the implant site during follow-up, especially during the first post-operative weeks. Based on the results of the current multicentre study, the Baha Attract can be considered as a treatment option for patients with the aforementioned hearing losses. Especially in the SSD patients, a careful selection procedure is warranted. Therefore, a pre-operative trial should be part of the decision-making process before fitting a patient with the Baha Attract System.

Stability, Survival, and Tolerability of an Auditory Osseointegrated Implant for Bone Conduction Hearing: Long-Term Follow-Up of a Randomized Controlled Trial.

OBJECTIVE: To compare implant stability, survival, and soft tissue reactions for a novel (test) and previous generation (control) percutaneous auditory osseointegrated implant for bone conduction hearing at long-term follow-up of 5 years. STUDY DESIGN: Single follow-up visit of a previously completed multicenter, randomized, controlled trial. PATIENTS: Fifty-seven of the 77 participants of a completed randomized controlled trial on a new auditory osseointegrated implant underwent a single follow-up visit 5 years after implantation, which comprised implant stability measurements and collection of Holgers scores. Additionally, implant survival was recorded for all 77 patients from the original trial. RESULTS: The test implant showed significantly higher implant stability quotient (ISQ) values compared with the control implant throughout the 5-year follow-up. Mean area under the curve of ISQ high from baseline to 5 years was 71.6 (standard deviation [SD] ±2.0) and 66.7 (SD ±3.4) for the test and control implant, respectively (p < 0.0001). For both implants, the mean ISQ value recorded at 5 years was higher compared with implantation (test group +2.03 [SD ±2.55, within group p < 0.0001] and control group +2.25 [SD ±4.95, within group p = 0.12]). No difference was noticed in increase from baseline between groups (p = 0.64). Furthermore, evaluation of soft tissue reactions continued to show superiority of the test implant. At the 5-year follow-up visit, one patient (2.5%) presented with a Holgers grade 2 in the test group, compared with four patients (23.5%) in the control group (p = 0.048); no patient presented with more severe soft tissue reactions. Excluding explantations, the survival rate was 95.8% for the test group and 95.0% for the control group. The corresponding rates including explantations were 93.9 and 90.0%. CONCLUSION: The test implant showed superiority in terms of higher mean ISQ values and less adverse soft tissue reactions, both at the single 5-year follow-up visit and during the complete follow-up. In addition, both implants showed an equally high implant survival.

Can the Hydroxyapatite-Coated Skin-Penetrating Abutment for Bone Conduction Hearing Implants Integrate with the Surrounding Skin?

INTRODUCTION: Percutaneous implants, such as bone conduction hearing implants, suffer from complications that include inflammation of the surrounding skin. A sealed skin-abutment interface can prevent the ingress of bacteria, which should reduce the occurrence of peri-abutment dermatitis. It was hypothesized that a hydroxyapatite (HA)-coated abutment in conjunction with soft tissue preservation surgery should enable integration with the adjacent skin. Previous research has confirmed that integration is never achieved with as-machined titanium abutments. Here, we investigate, in vivo, if skin integration is achievable in patients using a HA-coated abutment. MATERIALS AND METHODS: One titanium abutment (control) and one HA-coated abutment (case) together with the surrounding skin were surgically retrieved from two patients who had a medical indication for this procedure. Histological sections of the skin were investigated using light microscopy. The abutment was qualitatively analyzed using scanning electron microscopy. RESULTS: The titanium abutment only had a partial and thin layer of attached amorphous biological material. The HA-coated abutment was almost fully covered by a pronounced thick layer of organized skin, composed of different interconnected structural layers. CONCLUSION: Proof-of-principle evidence that the HA-coated abutment can achieve integration with the surrounding skin was presented for the first time.

Application and Interpretation of Resonance Frequency Analysis in Auditory Osseointegrated Implants: A Review of Literature and Establishment of Practical Recommendations.

OBJECTIVE: To establish standardization of implant stability measurements in auditory osseointegrated implants by means of resonance frequency analysis (RFA) through reviewing the currently published literature. METHODS: Studies reporting on RFA in auditory osseointegrated implants were identified, and the outcomes and the way these were reported were evaluated. RESULTS: Thirteen clinical studies reporting RFA outcomes of auditory osseointegrated implants were identified and analyzed, which demonstrated variations in methodology and reporting of data. The different reporting standards made a meta-analysis impossible. Heterogeneity and limitations were found in reporting of the types of implants, abutments, and SmartPegs used; study population sizes; follow-up duration; and, reporting of the implant stability quotient (ISQ). CONCLUSION: RFA is an interesting outcome of clinical studies on auditory osseointegrated implant research and might have potential as a clinically relevant tool for assessing implant stability. Because of the heterogeneous data that have been reported to date, the following guidelines for standardization of application and reporting were established. The implant and abutment type and length, and the type of SmartPeg should always be stated. Absolute stand-alone ISQ values should not be interpreted individually. ISQ values are at this moment most meaningful as a trend in the individual patient or in a population over time. No conclusions should be based on individual ISQ values. Standardized time points for RFA in research should be determined prospectively, with surgery as a baseline. After abutment replacement, individual ISQ trends from baseline cannot be interpreted anymore if the abutments differ in length.

Soft Tissue Integration of Hydroxyapatite-Coated Abutments for Bone Conduction Implants.

PURPOSE: The protocol for bone conduction hearing implant surgery involves reduction of soft tissues around the abutment to minimize the risk of skin-related complications. The present investigation was undertaken to demonstrate that hydroxyapatite-coated abutments provide improved soft tissue integration compared with conventional (pure titanium) abutments and are suitable for use without surgical removal of subepidermal soft tissues. MATERIALS AND METHODS: Forty-eight implants for bone conduction with two different types of abutments (test and control) were inserted in the skull parietal part of eight sheep. Test abutments had a hydroxyapatite-coated surface and a concave shape. Conventional titanium abutments were used as controls. A follow-up time of 4 weeks was used. Histomorphometric analyses of test and control samples were analyzed, and morphometric results were compared using mixed model analysis. RESULTS: Histological assessment showed healthy soft tissues around the abutments with limited or no signs of inflammation. Hydroxyapatite-coated abutments showed intimate dermal adherence, while less close contact was noted for control abutments. Statistically significant differences in mean pocket depth (0.4 vs 1.6 mm, p = .0013) and epidermal downgrowth (0.6 vs 2.0 mm, p = .0003) between test and control abutments were recorded. CONCLUSION: The study confirms that hydroxyapatite-coated abutments resulted in a significant reduction in pocket depth and improved soft tissue integration compared with conventional titanium abutments, possibly by providing tight adherence at the interface. Statistically significant reduced pocket depth formation and epidermal downgrowth were recorded.

Clinical performance of a new magnetic bone conduction hearing implant system: results from a prospective, multicenter, clinical investigation.

OBJECTIVE: The aim of the investigation was to prospectively evaluate, in a multicenter setting, the clinical performance of a new magnetic bone conduction hearing implant system. METHODS: The test device was the Cochlear Baha Attract System (Cochlear Bone Anchored Solutions AB, Mölnlycke, Sweden). Instead of the skin-penetrating abutment of traditional bone conduction hearing implants, the test device uses an implantable and an external magnet to transmit sound from the sound processor (SP) through intact skin to the skull bone. Twenty-seven adult patients with a conductive or mild mixed hearing loss or single-sided sensorineural deafness were included in the clinical investigation across four investigational sites. The patients were followed for 9 months after implantation. The study evaluated efficacy in terms of hearing performance compared with unaided hearing and with hearing with the SP on a softband. Patient benefit, soft tissue status, device retention, and safety parameters were monitored continuously throughout the investigation. RESULTS: Surgery and healing was uneventful. Statistically significant improvements in audibility and speech understanding in noise and quiet were recorded for the test device compared with preoperative unaided hearing. Speech recognition was similar or better than tests performed with the same SP on a softband. Good soft tissue outcomes were reported, without major pressure-related complications. At the end of the investigation, all patients continued to use and benefit from the device. CONCLUSION: The test device provides good hearing performance in patients with a conductive hearing loss or single-sided sensorineural deafness, with good wearing comfort and minimal soft tissue complications.

Long-term stability, survival, and tolerability of a novel osseointegrated implant for bone conduction hearing: 3-year data from a multicenter, randomized, controlled, clinical investigation.

OBJECTIVE: To compare the 3-year stability, survival, and tolerability of 2 osseointegrated implants for bone conduction hearing: a wide 4.5-mm-diameter moderately roughened implant with a rounded 6-mm abutment (test) and a 3.75-mm diameter as-machined implant with a conically shaped 5.5-mm abutment (control). STUDY DESIGN: In this randomized, prospective, controlled, multicenter clinical study, 77 adult patients were included. Test and control implants were randomly assigned in proportions of 2:1. The implants were loaded with the sound processor from 6 weeks postimplantation. Follow-up after surgery was conducted at 10 days; at 4, 6, 8, and 12 weeks; and at 6, 12, 24, and 36 months after surgery. At every visit, implant stability quotient (ISQ) values were recorded by means of resonance frequency analysis (RFA), and skin reactions were evaluated according to Holgers' classification. RESULTS: Statistically significantly higher mean ISQ values were recorded for the test implant compared with the control implant at each evaluation time point. Between 2 and 3 years after surgery, ISQ values decreased but remained above baseline values. Implant survival was high for both implants: 96.2% of the test implants and 100% of the control implants survived these 3 years. Statistically significantly improved soft tissue outcomes were observed in the test implant group. CONCLUSION: This extensive long-term clinical investigation demonstrated that the test implant is more stable in terms of ISQ-values and provides high tolerability for the soft tissue. The results show that implant loading at 6 weeks is safe.

Histologic evaluation of soft tissue integration of experimental abutments for bone anchored hearing implants using surgery without soft tissue reduction.

OBJECTIVE: The protocol for bone-anchored hearing implants (e.g., Baha) surgery involves reduction of soft tissues around the abutment to minimize the risk of skin-related complications. It is hypothesized that good soft tissue outcomes may be achieved without performing skin reduction if improved abutment designs and/or materials are used that provide enhanced integration with surrounding soft tissues. The aim of the study was to investigate soft tissue response to different abutment designs/materials. METHODS: Thirty-six Baha implants and abutments were inserted in the skull of six sheep without performing soft tissue reduction. Four different abutments were used: 1) standard Baha abutments, 2) hydroxyapatite-coated standard Baha abutments, 3) concave titanium abutments, and 4) hydroxyapatite-coated concave abutments. Healing times of 1, 2, and 4 weeks were used (2 animals per time point). Samples were analyzed using descriptive histology and morphometric measurements, and results were compared using Wilcoxon's signed-ranked test. RESULTS: Histologic assessment showed healthy soft tissues around the abutments with limited or no signs of inflammation. Hydroxyapatite-coated abutments showed tight adherence with dermis and limited epidermal downgrowth and pocket formation. Weaker adherence, often associated with significant epidermal downgrowth and pocket formation, was noted for noncoated titanium abutments. The mean pocket depth for abutment types A, B, C, and D was 1.38, 0.42, 1.51, and 0.24 mm, respectively. The difference between C and D was statistically significant (p = 0.031). CONCLUSION: The results showed enhanced dermal adherence and reduced epidermal downgrowth and pocket formation for hydroxyapatite-coated abutments, with the most significant effect recorded for the hydroxyapatite-coated abutments with a concave shape.

Stability, survival, and tolerability of a novel baha implant system: six-month data from a multicenter clinical investigation.

OBJECTIVE: Determination of the difference in implant stability between a novel Baha implant system (test) and the previous-generation implant system (control). METHODS: In an open, randomized, prospective multicenter clinical investigation, 77 adult patients with Baha implants were included. Test and control implants were randomly assigned in proportions of 2:1. Implant stability quotient (ISQ) values were recorded using resonance frequency analysis at the time of implantation and at 10 days, at 4, 6, 8, and 12 weeks, and at 6 months after surgery. Skin reactions were evaluated according to the Holgers classification. Sound processor fitting was performed from 6 weeks after implantation. RESULTS: Significantly higher mean ISQ values, measured between 0 and 6 months, were obtained for test compared to control implants (70.4 versus 65.4, p < 0.0001). Statistically significant differences were obtained for the study population as a whole and for the subgroup of patients loaded at 6 ± 1 weeks after implant surgery (63.6% of patients). Up to 12 weeks, Holgers rates were comparable, whereas at 6 months, more skin reactions (Grades 1 and 2) were observed in the control implant group. No reduction in mean ISQ values was observed after implant loading. CONCLUSION: The test implant showed higher mean ISQ values at the time of placement and over time. The level of osseointegration reached with the implants in adults as early as 6 weeks after implantation was sufficient to support the sound processor. The test implant system is expected to provide additional benefits related to the improvement of the degree of osseointegration, especially for patients with thin or compromised bone.

In vivo gene expression in response to anodically oxidized versus machined titanium implants.

A quantitative polymerase chain reaction technique (qPCR) in combination with scanning electron microscopy was applied for the evaluation of early gene expression response and cellular reactions close to titanium implants. Anodically oxidized and machined titanium miniscrews were inserted in rat tibiae. After 1, 3, and 6 days the implants were unscrewed and the surrounding bone was retrieved using trephines. Both the implants and bone were analyzed with qPCR. A greater amount of cells, as indicated with higher expression of 18S, was detected on the oxidized surface after 1 and 6 days. Significantly higher osteocalcin (at day 6), alkaline phosphatase (at days 3 and 6), and cathepsin K (at day 3) expression was demonstrated for the oxidized surface. Higher expression of tumor necrosis factor-alpha (at day 1) and interleukin-1beta (at days 1 and 6) was detected on the machined surfaces. SEM revealed a higher amount of mesenchymal-like cells on the oxidized surface. The results show that the rapid recruitment of mesenchymal cells, the rapid triggering of gene expression crucial for bone remodeling and the transient nature of inflammation, constitute biological mechanisms for osseointegration, and high implant stability associated with anodically oxidized implants.

A pilot study of complete edentulous rehabilitation with immediate function using a new implant design: case series.

BACKGROUND: The current investigation focuses on new implant designs for increased predictability in clinically demanding situations. Microtextured implant surfaces create favorable conditions for enhanced osseointegration of dental implants compared to implants with a smooth surface, and the macroscopic implant design may influence implant stability. PURPOSE: The aim of the present study was to retrospectively evaluate the clinical performance of a novel implant design in the rehabilitation of completely edentulous jaws and in combination with an immediate function protocol. MATERIALS AND METHODS: Forty-six consecutive patients received 189 study implants (NobelSpeedy concept implant, Nobel Biocare AB, Göteborg, Sweden) supporting 53 full-arch all-acrylic prostheses (44 maxilla, 9 mandible). The majority (66%) of the reconstructions were supported by four implants, of which the two posterior implants were tilted. All patients were followed for a minimum of 1 year. Radiographic assessment of the marginal bone level was performed. RESULTS: Two implants were lost in two patients, rendering a 1-year cumulative clinical survival rate of 98.9%. The marginal bone level was, on average, situated 1.2 +/- 0.7 mm below the implant-abutment interface after 1 year of loading. Good soft tissue health and overall esthetic outcome was reported. CONCLUSIONS: The results of the present pilot study indicate that fully edentulous jaws with various types of bone can be treated with high success and good esthetics using immediately loaded implants with the presented design, and that favorable marginal bone levels can be maintained.