Short-term results from seventy-six patients receiving a bone-anchored hearing implant installed with a novel minimally invasive surgery technique

Very Early Loading of a Bone-Anchored Hearing System Is Safe

OBJECTIVE

To investigate the feasibility of early sound processor loading with two separate bone-anchored hearing aid implants 1 to 2 weeks after implantation. Secondary endpoints included registration of any postoperative complications, skin reactions, and any adverse events.

STUDY DESIGN

Prospective, nonrandomized, noncontrolled, multicenter clinical trial.

SETTING

Tertiary referral center.

PATIENTS

Sixty adult patients, eligible for bone-anchored hearing aid surgery, were enrolled.

INTERVENTION

Implantation of the bone-anchored hearing aid implants were done using minimally invasive surgery with tissue preservation.

MAIN OUTCOME MEASURE

Implant stability quotient (ISQ) values were recorded using resonance frequency analysis. Follow-ups were scheduled 5 to 12 days, 4 to 8 weeks, 6 months, and 12 months postoperatively. Differences between the lowest ISQ values (ISQ low) over time were analyzed by paired-samples t test with a significance level of 0.05. Skin and soft tissue reactions were assessed according to Holger's classification.

RESULTS

Loading time of the Ponto Wide implant was 11.6 ± 1.4 days (SD) in average (median, 12 d; range, 7-19 d). Loading of the Ponto BHX implant was done 9.7 ± 3.5 days (SD) postoperatively (median, 9 d; range, 5-19 d). The implant stability increased significantly during the 12-month study period with both implants. One Ponto BHX implant was lost. Skin and soft tissue reactions were few in both groups. Across all planned follow-up visits, no skin and soft tissue reactions were observed in 86% (Ponto BHX implant) and 85% (Ponto Wide implant).

CONCLUSION

Very early loading of sound processors after percutaneous bone-anchored hearing system surgery is safe already 1 to 2 weeks postoperatively.

Minimally invasive surgery as a new clinical standard for bone anchored hearing implants-real-world data from 10 years of follow-up and 228 surgeries

Purpose

To explore the clinical practice development of different surgical techniques when installing bone-anchored hearing implants and their associated trends in outcomes.

Design

Retrospective study of 228 bone-anchored hearing implants in 200 patients, performed over a 10-year period between 2012 and 2022 in a referral hospital.

Method

Real-world data of demography, etiology, surgical setup, complications, and audiological outcomes were collected. Eligibility criteria from clinical practice were applied.

Results

The minimally invasive technique is associated with shorter surgery duration, 20 vs. 44 min as compared to a linear incision technique. The minimally invasive technique was also associated with a lower occurrence of complications when compared to linear incision techniques (intraoperative; 1.8% vs. 4.9%, postoperative; 49% vs. 66%). Most differences were seen in complications relating to skin and wound healing.

Conclusion

Adoption of a minimally invasive surgical technique for the installations of bone-anchored hearing implants can reduce surgical complexity without compromising safety aspects or clinical benefits.

Health Economic Cost Analysis for Percutaneous Bone Conduction Devices: The Minimally Invasive Ponto Surgery Versus Linear Incision Technique with Tissue Preservation

OBJECTIVES

To identify differences in mean cost per patient between the Minimally Invasive Ponto Surgery (MIPS) and the linear incision technique with tissue preservation (LITT-P).

STUDY DESIGN

Health economic cost analysis.

SETTING

The analysis was performed in a randomized multicenter controlled trial cohort.

PATIENTS

Adult patients eligible for unilateral bone conduction device surgery.

INTERVENTIONS

MIPS versus LITT-P surgery for bone conduction device implantation.

MAIN OUTCOME MEASURES

Perioperative and postoperative costs were identified and compared.

RESULTS

The difference in mean cost per patient between both techniques was €77.83 in favor of the MIPS after 22 months follow-up. The mean costs per patient were lower in the MIPS cohort for surgery (€145.68), outpatient visits (€24.27), systemic antibiotic therapy with amoxicillin/clavulanic acid (€0.30) or clindamycin (€0.40), abutment change (€0.36), and abutment removal (€0.18). The mean costs per patient were higher for implant and abutment set (€18.00), topical treatment with hydrocortison/oxytetracycline/polymyxine B (€0.43), systemic therapy with azithromycin (€0.09) or erythromycin (€1.15), local revision surgery (€1.45), elective explantation (€1.82), and implant extrusion (€70.42). Additional analysis of scenarios in which all patients were operated under general or local anesthesia or with recalculation when using current implant survival rates showed that differences in mean cost per patient were also in favor of the MIPS.

CONCLUSION

The difference between the MIPS and the LITT-P in mean cost per patient was €77.83 in favor of the MIPS after 22 months of follow-up. The MIPS is an economically responsible technique and could be promising for the future.

In-office Bone-Anchored Hearing Implants via Minimally Invasive Punch Technique in a Veteran Population

OBJECTIVE

Describe the feasibility and safety of completing bone-anchored hearing implants via the minimally invasive punch technique in the in-office setting.

STUDY DESIGN

This single-institution case series included 20 patients who underwent in-office bone-anchored hearing implant placement under local anesthesia from 2018 to 2021.

SETTING

Veterans Affairs Northern California Healthcare System.

METHODS

Following completion of the case series, patients were retrospectively surveyed regarding their satisfaction with this approach via a modified SSQ-8 (Surgical Satisfaction Questionnaire) to fit our purposes.

RESULTS

A total of 23 implants were completed in the in-office setting on 20 patients. Intra- and postoperative complication rates, including skin changes, irritation, infection, and poor wound healing, were similar to or better than currently published complication rates in the literature. In addition, patients reported overwhelmingly positive responses on the SSQ-8, almost universally stating that they were "very satisfied" with their clinic experience.

CONCLUSION

This case series suggests that it is feasible and safe to complete this procedure in the clinic under local anesthesia, but further prospective studies are needed to evaluate this in a more generalized population.

Non-invasive sampling procedure revealing the molecular events at different abutments of bone-anchored hearing systems–A prospective clinical pilot study

Purpose

To investigate the molecular activities in different compartments around the bone-anchored hearing system (BAHS) with either electropolished or machined abutments and to correlate these activities with clinical and microbiological findings.

Materials and methods

Twelve patients received machined or electropolished abutments after implant installation of BAHS. Peri-abutment fluid and tissue were collected from baseline to 12 months. Gene expression of cytokines and factors related to tissue healing and inflammation, regeneration and remodelling, as well as bacterial recognition were determined using quantitative-polymerase chain reaction (qPCR). The clinical status was evaluated using the Holgers scoring system, and bacterial colonisation was investigated by culturing.

Results

The gene expression of inflammatory cytokines (IL-8, IL-1β, and IL-10) and bacteria-related Toll-like receptors (2 and 4) was higher in the peri-abutment fluid than at baseline and in the peri-abutment tissue at 3 and 12 months. Conversely, the expression of genes related to tissue regeneration (Coll1a1 and FOXO1) was higher in the tissue samples than in the peri-abutment fluid at 3 and 12 months. Electropolished abutments triggered higher expression of inflammatory cytokines (IL-8 and IL-1β) (in peri-abutment fluid) and regeneration factor FOXO1 (in peri-abutment tissue) than machined abutments. Several cytokine genes in the peri-abutment fluid correlated positively with the detection of aerobes, anaerobes and Staphylococcus species, as well as with high Holger scores.

Conclusion

This study provides unprecedented molecular information on the biological processes of BAHS. Despite being apparently healed, the peri-abutment fluid harbours prolonged inflammatory activity in conjunction with the presence of different bacterial species. An electropolished abutment surface appears to be associated with stronger proinflammatory activity than that with a machined surface. The analysis of the peri-abutment fluid deserves further verification as a non-invasive sampling and diagnostic procedure of BAHS.

Long-term osseointegration of laser-ablated hearing implants in sheep cranial bone

Osseointegration, the ability for an implant to be anchored in bone tissue with direct bone-implant contact and allowing for continuous adaptive remodelling, is clinically used in different reconstructive fields, such as dentistry, orthopedics and otology. The latter uses a bone conducting sound processor connected to a skin-penetrating abutment that is mounted on a titanium implant placed in the temporal bone, thereby acting as a path for transmission of the vibrations generated by the sound processor. The success of the treatment relies on bone healing and osseointegration, which could be improved by surface modifications. The aim of this study was to evaluate the long-term osseointegration in a sheep skull model and compare a laser-ablated implant surface with a machined implant. Commercially available 4 mm titanium implants, either with a machined (Wide Ponto) or a laser-ablated surface (Ponto BHX, Oticon Medical, Sweden), were used in the current study. The surfaces were evaluated by scanning electron microscopy. The implantation was performed with a full soft tissue flap and the osteotomy was prepared using the MIPS drill kit (Oticon Medical, Sweden) prior to installation of the implants in the frontal bone of eight female sheep. After five months, biopsies including the implant and surrounding bone tissue obtained, processed and analysed using histology, histomorphometry, scanning electron microscopy and Raman spectroscopy. The animals healed well, without signs of adverse events. Histomorphometry showed a large amount of bone tissue around both implant types, with 75% of the threaded area occupied by bone for both implant types. A large amount of bone-implant contact was observed for both implant types, with 67%–71% of the surface covered by bone. Both implant types were surrounded by mature remodelled lamellar bone with high mineral content, corroborating the histological observations. The current results show that the laser-ablated surface induces healing similar to the well-known clinically used machined surface in ovine cranial bone. In conclusion, the present long-term experimental results indicate that a laser-ablated implant performs equally well as a clinically used implant with a machined surface. This, together with previously reported, improved early biomechanical anchorage, suggests future, safe and efficient clinical potential.

Single-Center Experience Evaluating Clinical Outcomes of a Novel-Guided Drill System for Percutaneous Bone-Anchored Hearing Implant

OBJECTIVE

Evaluate intraoperative and postoperative outcomes of a novel guided drill system for percutaneous bone-anchored hearing implants.

METHODS

Between January 2016 and February 2021, patients age ≥18 years deemed potential candidates for a bone-anchored hearing device, were formally assessed for candidacy and counseling. Those that qualified and opted to proceed were added to a prospectively maintained database, including demographic, clinical, and audiologic data. Intraoperative findings were reported, as were clinical outcomes at 7 days, 4 weeks, 3 months and 6 months postoperatively. The Holgers index was used to grade soft tissue reactions.

RESULTS

One hundred patients underwent the procedure. There were 56 women, and mean age was 54 years (18-84 yr). Ninety-six were done under local anesthetic. Mean surgical time was 13 minutes (9-27 min). No significant intraoperative events were noted. There were nine cases of implant loss, all in the first 50 cases. Mean duration of implant loss was 3.6 weeks (range, 2-5 wk). At the first postoperative visit, 82 had Holgers 0, 16 Holgers 1, 2 Holgers 2, and none Holgers 3. At the second postoperative visit, excluding the 9 with implant loss, 83 (91%) had Holgers 0, 6 (7%) Holgers 1, and 2 (2%) Holgers 2. None were Holgers 3.

CONCLUSIONS

The current study represents, to our knowledge, the largest series on the novel guided drill technique. Results show it is safe and efficient with low soft tissue complication rates. Drill bit design and technical modifications may have helped lower implant loss rate in this series over time.

The Minimally Invasive Star-Shaped Incision Technique and the Linear Incision Technique With Tissue Preservation for Percutaneous Bone Conduction Devices: A Retrospective Cohort Study

Purpose

To compare intra- and postoperative outcomes between the standard linear incision technique with tissue preservation (LITT-P) and the minimally invasive star-shaped incision (SSI).

Study Design

A retrospective cohort study.

Methods

Primary outcomes evaluated operative time, implant survival, and intra-operative complications. A secondary outcome evaluated soft tissue tolerability assessed by the Holger's classification.

Results

A total of 38 implants were placed (19 LITT-P; 19 SSI). The median and mean surgical duration for the LITT-P group was statistically shorter than the SSI group (p = 0.0001). No intra-operative complications were reported for both surgical approaches. Five implants were lost during postoperative follow-up: one in the LITT-P and four in the SSI cohort. Both cohorts showed favorable soft tissue tolerability. Less Holgers 1 and 2 and more Holgers 3 soft tissue reactions were observed after the LITT-P compared to the SSI.

Conclusion

The novel SSI approach could be an alternative option based on the theoretical benefits and found favorable (and similar) soft tissue outcomes. Implant loss and surgical time are aspects to investigate regarding long-term durability and warrant further research.

Ex vivo Evaluation of a New Drill System for Placement of Percutaneous Bone Conduction Devices

The procedure for installation of a percutaneous bone-conducting device has undergone significant improvements since its introduction 40 years ago. Today, the linear incision technique with tissue preservation (LITT-P) and the minimally invasive procedure (MIPS) are the most commonly used approaches. In both these techniques, a gradual increase of the osteotomy using a three-step drilling sequence is utilized, as this approach can allow a stepwise deepening and widening of the osteotomy in the mastoid and can prevent bone overheating. A new minimally invasive procedure (MONO) has been developed that allows an osteotomy to be performed and enables complete removal of the bone volume in one single drill step for a 4 mm implant using a novel parabolic twist drill. Here, the feasibility of the MONO procedure was qualitatively and quantitatively evaluated in terms of the dura response to drill trauma in comparison with the outcomes achieved with guide drills used for the LITT-P and MIPS techniques. Fresh frozen temporal bone from a human cadaver was subjected to penetration by three drills beyond the base of the mastoid bone to different depths. The sites were evaluated, and the damage to and possible penetration of the dura were determined. The results showed that for a drill depth exceeding mastoid bone thickness by not more than 1 mm, damage to the dura was limited or nonexistent, whereas for a drill depth exceeding bone thickness by 2 mm, damage increased, or the dura was penetrated. There was a trend toward more damage and penetration for both the round burr and MIPS guide drill compared with the MONO drill bit. From this experimental ex vivo study, it can be concluded that if the dura is encountered, the MONO system is not more inclined to penetrate the dura than the conventional LITT-P and MIPS systems.

Achieving stomal continence with an ileal pouch and a percutaneous implant

In this study, a soft-tissue-anchored, percutaneous port used as a mechanical continence-preserving valve in reservoir ileo- and urostomies was functionally and morphologically evaluated in eight dogs. During follow-up, the skin failed to attach to the implant, but the intestine inside the stoma port appeared to be attached to the mesh. After reaching adequate reservoir volume, the urostomies were rendered continent by attaching a lid to the implant. The experiments were ended at different time intervals due to implant-related adverse events. In only one case did the histological evaluation reveal integration at both the implant-intestine and implant-skin interfaces, with a low degree of inflammation and the absence of bacterial colonisation. In the remaining cases, integration was not obtained and instead mucosal downgrowth and biofilm formation were observed. The skin-implant junction was characterised by the absence of direct contact between the epidermis and the implant. Varying degrees of epidermal downgrowth, granulation tissue formation, inflammatory cell infiltration and bacterial growth and biofilm formation were prominent findings. In contrast, the subcutaneously located anchor part of the titanium port was well integrated and encapsulated by fibrous tissue. These results demonstrate the opportunity to achieve integration between a soft-tissue-anchored titanium port, skin and intestine. However, predictable long-term function could not be achieved in these animal models due to implant- and non-implant-related adverse events. Unless barriers at both the implant-skin and implant-intestine junctions are created, epidermal and mucosal downward migration and biofilm formation will jeopardise implant performance.

Comparison between linear incision and punch techniques for bone anchored hearing aid surgery

Objectives

To evaluate mean surgical time, incidence of soft tissue reactions, implant survival and intraoperative complications in both minimally invasive ponto surgery (MIPS) and the linear incision with tissue preservation technique (LT).

Methods

A retrospective review was carried out on 48 bone anchored hearing system (BAHS) patients between 2014 and 2019: 13 patients had undergone LT and formed one group, while 35 patients had undergone MIPS and formed the second group. Mean surgical time, intraoperative complications, implant loss and skin reaction were assessed at each post-operative examination. The Mann-Whitney U test was used for statistical analysis.

Results

The difference in the mean surgical time of 15 mins for MIPS and 36 mins for LT was statistically significant. No intraoperative complications were reported and implant survival was 100% in both groups. The incidence of adverse skin reactions was 7.7% for the LT group and 0% for the MIPS group at first follow-up examination.

Conclusions

Surgical mean time is shorter for MIPS, making this procedure more suitable for local anaesthesia and more cost effective. Moreover, both LT and MIPS demonstrate good surgical outcomes in terms of skin reactions according to Holgers score and equally excellent implant survival.

A Clinical Evaluation of Minimally Invasive Ponto Surgery With a Modified Drill System for Inserting Bone-Anchored Hearing Implants

OBJECTIVE

To compare 6-months outcomes of the modified minimally invasive Ponto surgery (m-MIPS) to both the linear incision technique with soft tissue preservation (LIT-TP), and original MIPS (o-MIPS) for inserting bone-anchored hearing implants (BAHIs).

STUDY DESIGN

Exploratory pilot study with one test group and two historical control groups.

SETTING

Tertiary referral center.

PATIENTS

In the test group, 24 patients (25 implants) were prospectively included. Each control group comprised 25 patients (25 implants) who participated in previously conducted clinical trials.

INTERVENTIONS

The test group received a BAHI using m-MIPS. The two control groups underwent surgery using the LIT-TP and o-MIPS, respectively.

MAIN OUTCOME MEASURES

Implant survival, implant stability, and surgery-related variables were compared between the test and control groups. Soft tissue status, skin sensibility, and subjective numbness were compared between m-MIPS and LIT-TP only.

RESULTS

Implant survival was comparable between m-MIPS and LIT-TP, whereas implant stability measurements were slightly lower for m-MIPS. M-MIPS resulted in comparable adverse skin reactions and skin sensibility, significantly reduced surgical time and slightly improved subjective numbness, compared with LIT-TP. Between m-MIPS and o-MIPS, no statistically significant differences in implant survival, implant stability and surgical time were observed.

CONCLUSIONS

A trend toward lower implant loss rates after m-MIPS was observed, when compared with o-MIPS. M-MIPS seems to be a good alternative to LIT-TP for inserting BAHIs, since most clinical outcomes were either comparable or slightly better for m-MIPS. Upon deciding on which technique to use, larger studies on implant survival should be performed. Furthermore, other aspects such as costs, training aspects and surgical experience should be evaluated.

Six-Month Clinical Outcomes for Bone-Anchored Hearing Implants: Comparison Between Minimally Invasive Ponto Surgery and the Linear Incision Technique With Tissue Preservation

OBJECTIVES

The aim of this study is to investigate and compare the clinical outcomes of minimally invasive ponto surgery (MIPS) to the linear incision technique with soft tissue preservation (LIT-TP) for percutaneous bone-anchored hearing implants (BAHI).

STUDY DESIGN

Prospective cohort study with a historical control group.

SETTING

Tertiary referral center.

PATIENTS

Twenty-five patients were prospectively included in the test group. The control group consisted of 25 patients who previously participated in another clinical trial and already underwent BAHI surgery.

INTERVENTION

All patients were implanted with a 4.5-mm-wide implant, using MIPS in the test group and the LIT-TP in the control group. Follow-up visits were scheduled 7 days, 21 days (sound processor fitting), 12 weeks and 6 months after surgery.

MAIN OUTCOME MEASURES

The primary outcome measure was skin sensibility around the abutment 6 months after surgery. Secondary outcomes were subjective numbness, surgery time, wound healing, adverse soft tissue reactions, cosmetic outcomes, implant stability quotient (ISQ), implant survival, and sound processor use.

RESULTS

Skin sensibility, adverse soft tissue reactions, and sound processor use were comparable between groups. The test group had a shorter surgery time and better cosmetic outcomes. More skin dehiscences and a statistically nonsignificant higher implant loss rate (12% vs 0%, p = 0.079) were observed in the test group.

CONCLUSION

MIPS is comparable to the LIT-TP regarding skin sensibility at 6 months and soft tissue tolerability. With MIPS, surgery time is further reduced and better cosmetic outcomes are reported. More research into MIPS, exact drill protocol, used instruments, and associated implant loss is warranted.

Multimodal Analysis of the Tissue Response to a Bone-Anchored Hearing Implant: Presentation of a Two-Year Case Report of a Patient With Recurrent Pain, Inflammation, and Infection, Including a Systematic Literature Review

Osseointegration is a well-established concept used in applications including the percutaneous Bone-Anchored Hearing System (BAHS) and auricular rehabilitation. To date, few retrieved implants have been described. A systematic review including cases where percutaneous bone-anchored implants inserted in the temporal bone were retrieved and analyzed was performed. We also present the case of a patient who received a BAHS for mixed hearing loss. After the initial surgery, several episodes of soft tissue inflammation accompanied by pain were observed, leading to elective abutment removal 14 months post-surgery. Two years post-implantation, the implant was removed due to pain and subjected to a multiscale and multimodal analysis: microbial DNA using molecular fingerprinting, gene expression using quantitative real-time polymerase chain reaction (qPCR), X-ray microcomputed tomography (micro-CT), histology, histomorphometry, backscattered scanning electron microscopy (BSE-SEM), Raman spectroscopy, and fluorescence in situ hybridization (FISH). Evidence of osseointegration was provided via micro-CT, histology, BSE-SEM, and Raman spectroscopy. Polymicrobial colonization in the periabutment area and on the implant, including that with Staphylococcus aureus and Staphylococcus epidermidis, was determined using a molecular analysis via a 16S-23S rDNA interspace [IS]-region-based profiling method (IS-Pro). The histology suggested bacterial colonization in the skin and in the peri-implant bone. FISH confirmed the localization of S. aureus and coagulase-negative staphylococci in the skin. Ten articles (54 implants, 47 patients) met the inclusion criteria for the literature search. The analyzed samples were either BAHS (35 implants) or bone-anchored aural epitheses (19 implants) in situ between 2 weeks and 8 years. The main reasons for elective removal were nonuse/changes in treatment, pain, or skin reactions. Most samples were evaluated using histology, demonstrating osseointegration, but with the absence of bone under the implants’ proximal flange. Taken together, the literature and this case report show clear evidence of osseointegration, despite prominent complications. Nevertheless, despite implant osseointegration, chronic pain related to the BAHS may be associated with a chronic bacterial infection and raised inflammatory response in the absence of macroscopic signs of infection. It is suggested that a multimodal analysis of peri-implant health provides possibilities for device improvements and to guide diagnostic and therapeutic strategies to alleviate the impact of complications.

Long-Term Outcomes of the Minimally Invasive Ponto Surgery vs. Linear Incision Technique With Soft Tissue Preservation for Installation of Percutaneous Bone Conduction Devices

Objective: Comparing the surgical outcomes of the Minimally Invasive Ponto Surgery (MIPS) technique with the linear incision technique with soft tissue preservation (LITT-P) for bone conduction devices after a follow-up of 22 months.

Methods: In this multicenter randomized controlled trial, there was the inclusion of 64 adult patients eligible for unilateral surgery. There was 1:1 randomization to the MIPS (test) or the LITT-P (control) group. The primary outcome was an (adverse) soft tissue reaction. Secondary outcomes were pain, loss of sensibility, soft tissue height/overgrowth, skin sagging, implant loss, Implant Stability Quotient measurements, cosmetic scores, and quality of life questionnaires.

Results: Sixty-three subjects were analyzed in the intention-to-treat population. No differences were found in the presence of (adverse) soft tissue reactions during complete follow-up. Also, there were no differences in pain, wound dehiscence, skin level, soft tissue overgrowth, and overall quality of life. Loss of sensibility (until 3-month post-surgery), cosmetic scores, and skin sagging outcomes were better in the MIPS group. The Implant Stability Quotient was higher after the LITT-P for different abutment lengths at various points of follow-up. Implant extrusion was nonsignificantly higher after the MIPS (15.2%) compared with LITT-P (3.3%).

Conclusion: The long-term results show favorable outcomes for both techniques. The MIPS is a promising technique with some benefits over the LITT-P. Concerns regarding nonsignificantly higher implant loss may be overcome with future developments and research.

Clinical Trial Registration:www.ClinicalTrials.gov, identifier: NCT02438618.

Punch vs open surgical techniques for placement of bone-anchored hearing implants: a systematic review and meta-analysis of skin reactions and operating time

PURPOSE

Several authors have reported their experience with the punch technique as compared to open surgical methods for bone-anchored hearing implants (BAHI). However, no study has attempted to aggregate current evidence. We aimed to compare post-operative skin complications and operating time between punch and open surgical techniques of BAHI via a systematic review and meta-analysis.

METHODS

Databases of PubMed, Embase, Scopus, BioMed Central, Ovoid, and CENTRAL were screened up to 15th February 2020 to include studies comparing punch and open surgical technique for BAHI.

RESULTS

Eight studies were included. Punch technique was compared with dermatome and linear incision techniques with and without soft tissue reduction. There was no difference in normal-to-moderate skin reaction between the punch and open surgical techniques (OR: 0.86 95% CI 0.23, 3.28 I² = 0%). The incidence of adverse skin reactions were also not different between the two groups. Meta-regression for different follow-up periods did not demonstrate any statistically significant results. Our results also indicated that punch technique requires less operating time, however, the inter-study heterogeneity in the analysis was very high. Similar results were seen on sub-group analysis based on the type of open surgical technique.

CONCLUSION

There may be no difference in skin tolerance between the punch technique and open surgical techniques. Operating time may be significantly reduced with the punch technique. Strong conclusions cannot be drawn owing to a limited number of studies. Further large-scale randomized trials are required.

Ten years of experience with the Ponto bone-anchored hearing system-A systematic literature review

Background

Bone‐anchored hearing systems (BAHSs) are widely used for hearing rehabilitation and are indicated in cases of conductive and mixed hearing loss and in single‐sided deafness. The Ponto system, that is one available option, has been on the market since 2009.

Objective of review

The aim of this study is to systematically review the literature reporting on the Ponto system, with regard to audiological and surgical outcomes and patient's quality‐of‐life scores.

Type of review

A systematic literature search was performed in the PubMed database 2009‐July 2019.

Search strategy

Search term: ((osseointegrated hearing aid) OR (bone conduction implant) OR (bone anchored hearing) OR BAHA OR BAHS OR BAHI). Pre‐defined inclusion and exclusion criteria were applied.

Evaluation method

English‐language articles reporting original clinical data (audiological, surgical or quality‐of‐life outcomes) on the Ponto system were included.

Articles reporting on Ponto and another BAHS system where the results on Ponto constituted less than 50% of the patient population or including only results on testband or softband devices were excluded.

Results

Audiological outcomes were discussed in 20 publications. Improvement against the unaided thresholds was demonstrated. The functional improvement was on average 33.9 dB. The effective gain or remaining air‐bone gap was on average 6.7 dB. All evaluated data showed aided speech reception thresholds significantly below normal speech level. Twenty‐seven publications reported surgical and follow‐up data for the Ponto system. Implant survival was 97.7%, adverse skin reactions (Holgers ≥ 2) were 5% across visits and 15% across patients. No complications were life‐threatening, causing permanent disability/damage or requiring a hospitalisation. Five studies reported quality of life using the Glasgow benefit inventory, 98% reported an improvement when analysing the score on an individual level.

Conclusions

The outcomes of this systematic review confirm that percutaneous systems provide consistent audiological benefits and improved quality of life for patients. Further, the review demonstrates that the percutaneous systems are safe, with relatively low complication rates. Skin‐related complications are the most common complication type and are experienced by approximately one patient out of seven, or in less than one of 20 follow‐up visits.

Microbiome on the Bone-Anchored Hearing System: A Prospective Study

The bone-anchored hearing system (BAHS) has evolved to a common treatment option for various types of hearing revalidation. The BAHS consists of an implant in the skull that breeches the skin. Soft tissue reactions are a common complication associated with BAHS and are generally poorly understood. This study aims to investigate the influence of BAHS and associated skin reactions around the implant. A total of 45 patients were prospectively followed from implantation up to at least 1 year. Swabs were obtained at baseline, 12 weeks follow-up and during cases of inflammation (Holgers score ≥2). The microbiota was assessed using IS-pro^TM, a bacterial profiling method based on the interspace region between the 16S–23S rRNA genes. Detection of operational taxonomic units, the Shannon Diversity Index, sample similarity analyses and Partial Least Squares Discriminant Analysis (PLS-DA) were employed. Staphylococcus epidermidis, Streptococcus pneumoniae/mitis, Propionibacterium acnes, Staphylococcus capitis, Staphylococcus hominis, Bifidobacterium longum, Haemophilus parainfluenzae, Lactobacillus rhamnosus, Bordetella spp., Streptococcus sanguinis, Peptostreptococcus anaerobius, Staphylococcus aureus, Lactococcus lactis, Enterobacter cloacae, and Citrobacter koseri were the most commonly found bacterial species. S. pneumoniae/mitis was significantly more often observed after implantation, whereas P. acnes was significantly less observed after implantation compared with baseline. The relative abundance of S. epidermidis (17%) and S. aureus (19.4%) was the highest for the group of patients with inflammation. The Shannon Diversity Index was significantly increased after implantation compared with pre-surgical swabs for Firmicutes, Actinobacteria, Fusobacteria, Verrucomicrobia (FAFV), but not for other phyla. When combining all phyla, there was no significant increase in the Shannon Diversity Index. The diversity index was similar post-surgically for patients experiencing inflammation and for patients without inflammation. With a supervised classifier (PLS-DA), patients prone to inflammation could be identified at baseline with an accuracy of 91.7%. In addition, PLS-DA could classify post-surgical abutments as non-inflamed or inflamed with an accuracy of 97.7%. This study shows the potential of using IS-pro^TM to describe and quantify the microbiota associated with the percutaneous BAHS. Furthermore, the results indicate the possibility of an early identification of patients susceptible to adverse skin reaction following implantation. Both S. aureus and S. epidermidis should be considered as relevant bacteria for BAHS-associated inflammation.

Bone Conduction Implants for Hearing Rehabilitation in Skull Base Tumor Patients

Bone conduction implants transfer sound to the inner ear through direct vibration of the skull. In patients with skull base tumors and infections, these devices can bypass a dysfunctional ear canal and/or middle ear. Though not all skull base surgery patients opt for bone conduction hearing rehabilitation, a variety of these devices have been developed and marketed over time. This article reviews the evolution and existing state of bone conduction technology.

Bone-anchored hearing implant surgery: our experience with linear incision and punch techniques

SUMMARY

In recent years, bone-anchored hearing implants (BAHIs) have found wider application in the treatment of conductive and mixed hearing loss. Several surgical techniques have been developed to reduce complications, enhance healing and improve audiological and aesthetic results. We report our experience on the use of three BAHI surgery techniques: Group 1, linear incision with thinning of the subcutaneous tissue; Group 2, linear incision without thinning of the subcutaneous tissue; Group 3, punch technique (Minimally Invasive Ponto Surgery, MIPS). We retrospectively analysed patients undergoing BAHI surgery; results were evaluated on the basis of any intra-operative complication, duration of surgery and occurrence of adverse effects at the implantation site over 1 year of follow-up. We collected a total of 30 implantations (12 for Group 1, 8 for Group 2, 10 for Group 3) with an intra-operative complication rate of 25%, 0% and 10%, respectively. The average surgical time was 62.08 minutes, 34.37 minutes and 18.7 minutes respectively. During follow-up, we reported the occurrence of adverse effects in 10.63% of observations in Group 1, 3.12% in Group 2 and 2.5% in Group 3. This study confirms the low rate of intra and postoperative complications during BAHI surgery and documents the simplicity of execution of the novel MIPS technique, with a significant reduction in surgical time compared to the other two techniques, and positive effects in terms of health care costs.

Long term follow-up demonstrating stability and patient satisfaction of minimally invasive punch technique for percutaneous bone anchored hearing devices

OBJECTIVE

Minimally Invasive Ponto Surgery (MIPS) was recently described to facilitate the placement of percutaneous bone anchored hearing devices. As early adopters of this new procedure, we sought to perform a quality assurance project using our own small prospective cohort to justify this change in practice. We chose to examine device stability and to gauge our patients' perspective of the surgery and their overall satisfaction with the process.

METHODS

A total of 12 adult patients who underwent MIPS between 2016 and 2017 with a minimum post-operative follow-up of 12 months were included in this study. A prospective MIPS research clinic was used to follow patients, assess the implant site soft tissue status and gather qualitative information through patient interviews and surveys.

RESULTS

The mean (SD) soft tissue status score averages using the IPS Scale were low for inflammation 0.1 (0.1), pain 0.1 (0.1), skin height 0.2 (0.1) and total IPS score 0.4 (0.3) indicating minimal soft tissue changes. Patient experiences with MIPS were overwhelmingly positive in reports through the MIPS modified SSQ-8. All patients reported speedy recoveries and no long-term complications. There were zero device losses.

CONCLUSION

The series presented in this paper represents the first MIPS cohort with long term follow-up to be published to date in North America. Our findings conclude both device stability and patient satisfaction with no loss of fixtures. Consequently, we have adopted MIPS as our procedure of choice for the placement of all percutaneous BAHDs.

Minimally Invasive Ponto Surgery Versus the Linear Incision Technique With Soft Tissue Preservation for Bone Conduction Hearing Implants: A Multicenter Randomized Controlled Trial

OBJECTIVE

To compare the surgical outcomes of the Minimally Invasive Ponto Surgery (MIPS) technique with those of the linear incision technique with soft-tissue preservation for bone-anchored hearing systems (BAHS).

DESIGN

Sponsor-initiated multicenter, open, randomized, controlled clinical trial.

SETTING

Maastricht University Medical Centre, Ziekenhuisgroep Twente and Medisch Centrum Leeuwarden, all situated in The Netherlands.

PARTICIPANTS

Sixty-four adult patients eligible for unilateral BAHS surgery.Interventions Single-stage BAHS surgery with 1:1 randomization to the linear incision technique with soft-tissue preservation (control) or the MIPS (test) group.

PRIMARY AND SECONDARY OUTCOME MEASUREMENTS

Primary objective: compare the incidence of inflammation (Holgers Index ≥ 2) during 12 weeks' follow-up after surgery. Secondary objectives: skin dehiscence, pain scores, loss of sensibility around the implant, soft-tissue overgrowth, skin sagging, implant extrusion, cosmetic results, surgical time, wound healing and Implant Stability Quotient measurements.

RESULTS

Sixty-three subjects were analyzed in the intention-to-treat population. No significant difference was found for the incidence of inflammation between groups. Loss of skin sensibility, cosmetic outcomes, skin sagging, and surgical time were significantly better in the test group. No statistically significant differences were found for dehiscence, pain, and soft-tissue overgrowth. A nonsignificant difference in extrusion was found for the test group. The Implant Stability Quotient was statistically influenced by the surgical technique, abutment length, and time.

CONCLUSION

No significant differences between the MIPS and the linear incision techniques were observed regarding skin inflammation. MIPS results in a statistically significant reduction in the loss of skin sensibility, less skin sagging, improved cosmetic results, and reduced surgical time. Although nonsignificant, the implant extrusion rate warrants further research.

Cytokine expression profile in the bone-anchored hearing system: 12-week results from a prospective randomized, controlled study

Objective

To study the effect of implanting the percutaneous bone‐anchored hearing system (BAHS) itself and inflammation of the peri‐abutment skin warrant clarification. In this study, we aimed to acquire further insight into the immune responses related to BAHS surgery and peri‐implant skin inflammation.

Materials and Methods

During surgery and 12 weeks post‐implantation, skin biopsies were obtained. If applicable, additional biopsies were taken during cases of inflammation. The mRNA expression of IL‐1β, IL‐6, IL‐8, TNFα, IL‐17, IL‐10, TGF‐ß, MIP‐1α, MMP‐9, TIMP‐1, COL1α1, VEGF‐A, FGF‐2 TLR‐2, and TLR‐4 was quantified using qRT‐PCR.

Results

Thirty‐five patients agreed to the surgery and 12‐week biopsy. Twenty‐two patients had mRNA of sufficient quality for analysis. Ten were fitted with a BAHS using the minimally invasive Ponto surgery technique. Twelve were fitted with a BAHS using the linear incision technique with soft‐tissue preservation. Five biopsies were obtained during episodes of inflammation. The post‐implantation mRNA expression of IL‐1β (P = .002), IL‐8 (P = .003), MMP9 (P = .005), TIMP‐1 (P = .002), and COL1α1 (P < .001) was significantly up‐regulated. IL‐6 (P = .009) and FGF‐2 (P = .004) mRNA expression was significantly down‐regulated after implantation. Within patients, no difference between post‐implantation mRNA expression (at 12 weeks) and when inflammation was observed. Between patients, the expression of IL‐1β (P = .015) and IL‐17 (P = .02) was higher during cases of inflammation compared with patients who had no inflammation at 12‐week follow‐up.

Conclusions

As part of a randomized, prospective, clinical trial, the present study reports the molecular profile of selected cytokines in the soft tissue around BAHS. Within the limit of this study, the results showed that 12 weeks after BAHS implantation the gene expression of some inflammatory cytokines (IL‐8 and IL‐1β) is still relatively high compared with the baseline, steady‐state, expression. The up‐regulation of anabolic (COL1α1) and tissue‐remodeling (MMP‐9 and TIMP1) genes indicates an ongoing remodeling process after 12 weeks of implantation. The results suggest that IL‐1β, IL‐17, and TNF‐α may be interesting markers associated with inflammation.

The clinical outcome and microbiological profile of bone-anchored hearing systems (BAHS) with different abutment topographies: a prospective pilot study

Purpose

In this prospective clinical pilot study, abutments with different topologies (machined versus polished) were compared with respect to the clinical outcome and the microbiological profile. Furthermore, three different sampling methods (retrieval of abutment, collection of peri-abutment exudate using paper-points, and a small peri-abutment soft-tissue biopsy) were evaluated for the identification and quantification of colonising bacteria.

Methods

Twelve patients, seven with machined abutment and five with polished abutment, were included in the analysis. Three different sampling procedures were employed for the identification and quantification of colonising bacteria from baseline up to 12 months, using quantitative culturing. Clinical outcome measures (Holgers score, hygiene, pain, numbness and implant stability) were investigated.

Results

The clinical parameters, and total viable bacteria per abutment or in tissue biopsies did not differ significantly between the polished and machined abutments. The total CFU/mm² abutment and CFU/peri-abutment fluid space of anaerobes, aerobes and staphylococci were significantly higher for the polished abutment. Anaerobic bacteria were detected in the tissue biopsies before BAHS implantation. Anaerobes and Staphylococcus spp. were detected in all three compartments after BAHS installation. For most patients (10/12), the same staphylococcal species were found in at least two of the three compartments at the same time-point. The common skin coloniser Staphylococcus epidermidis was identified in all patients but one (11/12), whereas the pathogen Staphylococcus aureus was isolated in five of the patients. Several associations between clinical and microbiological parameters were found.

Conclusions

There was no difference in the clinical outcome with the use of polished versus machined abutment at 3 and 12 months after implantation. The present pilot trial largely confirmed a suitable study design, sampling and analytical methodology to determine the effects of modified BAHS abutment properties.

Level of evidence

2. Controlled prospective comparative study.

Electronic supplementary material

The online version of this article (10.1007/s00405-018-4946-z) contains supplementary material, which is available to authorized users.

Preliminary audiologic and peri-operative outcomes of the Sophono™ transcutaneous bone conduction device: A systematic review

OBJECTIVE

To delineate the auditory functional improvement and peri-operative outcomes of the Sophono™ transcutaneous bone conduction device.

METHODS

Eligible articles presenting patients implanted with the Sophono™ were identified through a comprehensive search of PubMed and Embase electronic databases. All relevant articles were reviewed to justify inclusion independently by 2 authors. Studies that successfully passed critical appraisal for directness of evidence and risk of bias were included.

RESULTS

From a total of 125 articles, 8 studies encompassing 86 patients using 99 implants were selected. Most patients (79.1%) were children. Ear atresia (67.5%) was the most frequently reported indication for Sophono™ implantation. Overall pure tone average auditory improvement was 31.10 (±8.29) decibel. During a mean follow-up time of 12.48 months, 25 patients (29%) presented with post-operative complications from which 3 were deemed as serious implant-related adverse events (3.5%).

CONCLUSIONS

The Sophono™ transcutaneous bone conduction device shows promising functional improvement, no intra-operative complications and minor post-operative skin related complications. If suitable, the device could be a proposed solution for the rehabilitation of hearing in children meeting eligibility criteria. A wearing schedule must be implemented in order to reduce magnet-related skin complications.

The Use of Cone Beam Computed Tomography in Assessing the Insertion of Bone Conduction Hearing Implants

OBJECTIVE

This study aimed to compare postoperative cone beam CT (CBCT) imaging to implant stability quotient (ISQ) measurement and direct caliper measurements as a suitable technique to assess bone conduction hearing implant (BCHI) seating and insertion depth.

METHODS

In vitro, BCHIs were completely (n = 9) and partially inserted (n = 9) in bone blocks of different densities and subsequently scanned. Scans were processed using 3DSlicer 4.3.1 and Mathematica 10.3. ISQ measurements were obtained for all BCHIs mounted with different abutment lengths (9, 12, and 14 mm). CBCT imaging was performed for patients with a clinical indication.

RESULTS

In vitro, 95% prediction intervals for partially inserted and completely inserted BCHIs were determined. ISQ values significantly decreased with partial insertion, low-density artificial bone, and longer abutment lengths. Evaluation of in vitro and in vivo 3D models allowed for assessment of insertion depth and inclination.

CONCLUSION

CBCT imaging allows to study implant seating and insertion depth after BCHI surgery. This can be useful when visual confirmation is limited. It is possible to distinguish a partial BCHI insertion from a complete insertion in artificial bone blocks. This technique could prove to be a valuable research tool. In vitro, ISQ values for Ponto BCHIs relate to abutment length, insertion depth, and artificial bone density.