A Systematic Review on Factors Associated With Percutaneous Bone Anchored Hearing Implants Loss

Resonance Frequency Analysis Identifies Implant- and Host-Related Factors Associated With Bone-Anchored Hearing Implant Stability

HYPOTHESIS

Resonance frequency analysis (RFA) is a reliable, noninvasive method to assess the stability of bone-anchored hearing implants (BAHIs), although surgical-, implant-, and host-related factors can affect its outcome.

BACKGROUND

BAHI plays an important role in restoring hearing function. However, implant- and host-related factors contribute to premature implant extrusion. To mitigate this, noninvasive methods to assess implant stability, along with a better understanding of factors contributing to BAHI failure, are needed.

METHODS

We evaluated the utility of RFA to quantify implant stability in sawbone (bone mimicking material), 29 human cadaveric samples, and a prospective cohort of 29 pediatric and 27 adult participants, and identified factors associated with implant stability. To validate the use of RFA in BAHI, we compared RFA-derived implant stability quotient (ISQ) estimates to peak loads obtained from mechanical push-out testing.

RESULTS

ISQ and peak loads were significantly correlated (Spearman rho = 0.48, p = 0.0088), and ISQ reliably predicted peak load up to 1 kN. We then showed that in cadaveric samples, abutment length, internal table bone volume, and donor age were significantly associated with implant stability. We validated findings in our prospective patient cohort and showed that minimally invasive Ponto surgery (MIPS; versus linear incision), longer implantation durations (>16 wk), older age (>25 yr), and shorter abutment lengths (≤10 mm) were associated with better implant stability. Finally, we characterized the short-term reproducibility of ISQ measurements in sawbone and patient implants.

CONCLUSIONS

Together, our findings support the use of ISQ as a measure of implant stability and emphasize important considerations that impact implant stability, including surgical method, implant duration, age, and abutment lengths.

Long-Term Results of the Linear Incision Technique With Tissue Reduction Versus Tissue Preservation for Inserting Bone-Anchored Hearing Implants: The Ongoing Optimization in Bone Implant Surgery

OBJECTIVE

To compare the long-term outcomes of the linear incision technique with tissue reduction (LIT-TR) and the linear incision technique with tissue preservation (LIT-TP) for inserting bone-anchored hearing implants (BAHIs).

STUDY DESIGN

Single-center retrospective cohort study.

SETTING

Large general teaching hospital.

PATIENTS

A total of 231 adult patients were included between August 2005 and October 2020, with a minimum follow-up time of 6 months.

INTERVENTION

The test group received a BAHI using the LIT-TP (N = 147). The control group underwent surgery using the LIT-TR (N = 84).

MAIN OUTCOME MEASURES

Soft tissue reactions, skin thickening, postoperative complications (e.g., wound dehiscence), and implant loss were compared between the test and control group. Furthermore, Cochlear Bone Anchored Solutions AB (Mölnlycke, Sweden) and Oticon Medical AB (Askim, Sweden) implants/abutments within the LIT-TP cohort were compared. Validated questionnaires were used to quantify patients' health-related quality of life (HRQoL).

RESULTS

Significantly more cases with wound dehiscence and adverse soft tissue reactions (Holgers ≥2) were observed in the LIT-TR cohort (p < 0.001). However, the LIT-TP cohort showed significantly more cases with skin thickening (requiring treatment) within the first 2 years after implantation. There were no differences in implant loss rates, overall soft tissue reactions (Holgers >1), and overall HRQoL between the two patient groups. Significant improvement in the patients' HRQoL after implementation of a BAHI was found in both techniques. The Ponto Wide implant/abutment showed less frequent skin thickening (requiring treatment) and fewer soft tissue reactions compared with the BIA400 implant/abutment.

CONCLUSION

This large-scale study demonstrates that the LIT-TP shows excellent long-term outcomes, including a low incidence of implant failure.

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.

The Oticon Ponto System in Adults With Severe-to-Profound and Mixed Hearing Loss: Audiologic Outcomes and Patient Satisfaction

OBJECTIVE

To measure audiologic outcomes and self-assessed satisfaction with the Ponto system in a group of patients who had severe to profound and mixed hearing loss.

STUDY DESIGN

Retrospective case review.

SETTING

Tertiary referral center.

PATIENTS

Sixteen patients aged 21 to 74 years with severe-to-profound and mixed hearing loss (bone conduction thresholds, ≥45 dB HL).

INTERVENTIONS

Ponto implant surgery.

MAIN OUTCOME MEASURES

Pure-tone audiometry, free-field hearing thresholds, effective gain, word recognition score in quiet, and speech reception threshold (SRT) in noise were assessed. Patient-reported outcomes were collected using the Clinical Global Impression Scale, Glasgow Benefit Inventory, and Abbreviated Profile of Hearing Aid Benefit. Information concerning any medical complications was also gathered.

RESULTS

Both word recognition score and SRT were significantly better after 12 months compared with before surgery. At normal speech level (65 dB SPL), 12 of 16 users had speech discrimination ≥70%. However, at the 12-month follow-up, the average effective gain was -6.2 dB. In general, the self-report outcomes showed good satisfaction in most patients. Postoperatively, skin complications were noted in six patients, of whom two underwent reoperation. All patients were still using the Ponto after an average observation time of 2.7 years.

CONCLUSION

Although skin complications were not uncommon, the Ponto system seems to be an effective method of improving hearing performance and provides subjective satisfaction in real-life situations in patients with severe-to-profound and mixed hearing loss. However, considering the significantly increased bone conduction thresholds and the risk of their further deterioration, long-term follow-up is still needed.

Clinical Evaluation of a Novel Laser-Ablated Titanium Implant System for Bone Anchored Hearing Systems in a Pediatric Population and the Relationship of Resonance Frequency Analysis With Implant Survival

OBJECTIVE

To evaluate the clinical outcomes of pediatric patients implanted a novel 4.5 mm wide laser ablated titanium bone anchored implant system and to evaluate the implant stability over the first 12-month period.

STUDY DESIGN

A prospective, single-subject, repeated measure, cohort study. Participants served as their own controls.

SETTING

Community and tertiary referral hospital pediatric assessment center.

PATIENTS

A total of 115 consecutive pediatric patients aged 4 to 15 years were implanted with 176 laser ablated titanium bone anchored implants from January 2016 to January 2019.

MAIN OUTCOME MEASURE

Clinical outcomes, implant failure rates, and post implantation implant stability quotient (ISQ) scores were studied over the first 12-month period. Data were analyzed for statistical significance through mixed effect modeling, with the significance level p = 0.01.

RESULTS

A median 12-month survival of 96.6% was observed. Six implants (3.5%) were lost in total, one of these (0.6%) was lost due to trauma. Adverse skin reactions (Holgers grade 2-4) were observed in 4.4% of all postoperative visits, occurring in 22 individuals (19.1%). Neither the ISQ high (ISQH) nor ISQ low (ISQL) values increased significantly between the stage 1 and 2 surgeries. In contrast, the ISQ results, irrespective of abutment size, demonstrated an increasing trend from 49.1 to 57 over the 12 months review period. A statistically significant change was only demonstrated from the 3 months follow up onwards.

CONCLUSION

The use of 4.5 mm wide laser-ablated titanium bone anchored hearing implants resulted in superior survival rates and excellent clinical outcomes compared with previous implant systems.

Reliability of Postsurgical Soft Tissue Reaction Grading Scales for Bone-anchored Hearing Implants

OBJECTIVE

This study aims to assess and compare the reliability of the Holgers, the IPS, and the Tullamore scales for skin tolerability assessment of postoperative bone-anchored hearing implant images.

STUDY DESIGN

A survey study and retrospective review of percutaneous osseointegrated auditory implant images for scoring using three skin classification scales.

SETTING

McGill University Health Center, Montreal, Quebec, Canada.

PARTICIPANTS

Healthcare workers experienced and inexperienced with osseointegrated auditory implant skin classification scales.

MAIN OUTCOME MEASURES

Participation involved completing: 1) survey questionnaires assessing experience with osseointegrated auditory implants and related skin reactions and 2) scoring postoperative osseointegrated auditory implant with surrounding skin images using the Holgers Classification, the IS (of the IPS) scale, and the Tullamore Classification. Participants were asked to rate 12 images of postoperative osseointegrated auditory implant and surrounding soft tissue. This process was repeated until participants scored all images using the three scales; each rater graded 36 images in total. The order in which scales were presented occurred at random. Intraclass correlation coefficients were calculated to assess reliability.

RESULTS

Thirty-one participants were recruited to the study. Fourteen (45.2%) had experience with at least 1 osseointegrated auditory implant skin classification scale, while 17 (54.8%) did not have experience. The wide and overlapping 95% confidence intervals of the intraclass correlation coefficients results do not provide us with enough evidence to define a well-established degree and hierarchy of reliability when comparing the scales. Among experienced raters, all scales presented moderate to good reliability.

CONCLUSIONS

The Holgers Classification, the IPS scale, and the Tullamore Classification all present moderate to good reliability when used by experienced raters to assess skin reactions following surgical implantation of an osseointegrated hearing device. As a result, clinicians should use these scales with a degree of caution. The findings of this study do not provide us with enough evidence to single out one of the scales as a standard to follow, but more extensive studies are required to assess the reliability of the scales.

A retrospective evaluation of minimally invasive ponto surgery (MIPS) in two pediatric centers

BACKGROUND

Percutaneous bone anchored hearing systems have been used effectively for over forty years with low rates of complications. Minimally Invasive Ponto Surgery (MIPS) is a surgical technique performed through a puncture hole that has been reported to minimize soft tissue trauma and decrease operative time. Due to it being a relatively new procedure there remains a paucity of pediatric outcomes data.

METHODS

Pediatric patients from two tertiary pediatric otolaryngology centers between 2016 and 2019 who underwent MIPS were included in this study. Charts were retrospectively reviewed for indications for surgery, implant and abutment type, overlying skin thickness, skin-to-skin time, Holgers score at three, six and twelve months, revision surgery and time to abutment fitting.

RESULTS

Fourteen patients, two with bilateral procedures met inclusion criteria (mean age = 8.07 ± 2.87years). The mean overlying skin thickness was 5.13 ± 3.18mm. 9.44% of visits had an adverse skin reactionOne patient required surgery forskin overgrowth. One implant loss (6.3%) was reported, following trauma to the abutment. Mean MIPS skin to skin times were 12.4 ± 2.6 min, markedly different that the Baha^® Attract and Connect which were 56 and 53 min, respectively.

CONCLUSION

This study represents the largest pediatric MIPS cohort to date, and our results are similar to published adult studies.

Five year clinical outcomes and evaluation following implantation of the Oticon™ wide bone anchored hearing system in 47 children

OBJECTIVES

The Oticon™ wide implant system was launched in 2009 and used at Birmingham Children's Hospital from 2014. To evaluate clinical outcomes of the Oticon™ wide implant (Oticon Medical), with a focus on skin complication rates and fixture loss over a 5-year period in a tertiary paediatric hospital in the UK.

METHODS

Retrospective 5-year longitudinal case record review of 47 children who were implanted with the Oticon™ wide implant system at Birmingham Children's Hospital (BCH) between January 2014 and January 2016.

RESULTS

47 children (27 M:20F) were implanted with 70 Oticon wide implants 23 bilateral, 27 unilateral. Mean age at the time of implantation was 9y 6 m. The follow up was for a mean of 5.4 years. Significant soft tissue complications requiring treatment was found in 11% (n = 8) of loaded fixtures, abutment tightening on two patients, abutment exchange 6% (n = 4) and a 10% (n = 7) fixture failure.

CONCLUSION

The Oticon™ wide implant system produces favourable results with regards to peri-abutment skin complications, fixture stability and revision surgery rates when compared to similar cohorts of children studied at Birmingham Children's Hospital.

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.

Experience with Minimally Invasive Ponto Surgery and Linear Incision Approach for Pediatric and Adult Bone Anchored Hearing Implants

Purpose:

To compare intra- and postoperative outcomes between the standard linear incision with tissue preservation and the Minimally Invasive Ponto Surgery (MIPS).

Study Design:

A non-randomized retrospective cohort series.

Methods:

Medical files were reviewed of adult and pediatric bone anchored hearing implant recipients. Extracted outcomes included patient characteristics, implant survival, operative time, anesthesia use, intra and postoperative complications, soft tissue tolerability assessed by the Holger’s classification, and implant stability assessed by the Resonance Frequency Analysis (RFA). Outcomes were compared between two surgeries.

Results:

A total of 59 implants were placed (21 MIPS; 38 linear). Conductive hearing loss was the most common etiology for implantation. Surgery was conducted under local anesthesia in 67% of MIPS patients and 16% of linear patients. No intraoperative complications were reported for both surgical approaches and no implants were lost. Patients undergoing implantation via the MIPS approach displayed less skin reaction postoperatively, however this was not significant ( P = .2848). The most common Holgers score for both groups was grade 1. The median and mean surgical duration for the MIPS group was statistically lower than the linear group ( P = .0001). Implant stability measured by the RFA implant stability quotient was greater in the MIPS cohort.

Conclusion:

The MIPS approach seems either similar or superior to the linear approach in all perioperative outcomes evaluated. Outcomes such as surgical duration, anesthesia choice and implant stability measurements support implantation through the MIPS approach for patients meeting eligibility criteria.

Surgical Explantation of Bone-Anchored Hearing Devices: A 10-year Single Institution Review

Objective

To identify clinical variables associated with the decision to surgically discontinue bone-anchored hearing device function.

Study Design

Retrospective chart review.

Setting

Tertiary neurotology referral center.

Subjects and Methods

This study examines surgical interventions performed on existing bone-anchored hearing devices at a single institution from 2008 to 2018. Patient characteristics, indications for implantation, and complications prompting surgical intervention were assessed.

Results

Seventy-seven cases were included in this study. Among patients in the younger cohort (<37 years old), 100% (13 of 13) of those discontinuing their device had a contralateral normal-hearing ear. Conversely, 0% (0 of 14) of the younger patients with bilateral hearing loss surgically discontinued their devices. Within the older cohort (≥37 years old), female patients ( P = .002) and those with an increased body mass index ( P = .035) were more likely to surgically discontinue their devices. Multivariate analysis revealed that a contralateral normal-hearing ear ( P = .001) and infection without soft tissue overgrowth of the abutment ( P = .026) were the strongest predictors of device discontinuation, after adjusting for potential confounders.

Conclusion

Surgical discontinuation is associated with several clinical variables. Targeted interventions that are viable alternatives to removal, such as device relocation, should be presented to younger patients with a contralateral normal-hearing ear who experience persistent complications. Patients with persistent infection in the absence of soft tissue overgrowth would especially benefit from enhanced counseling on proper hygiene.