Titanium fixtures for bone-conduction devices and the influence of type 2 diabetes mellitus

Long-Term Outcomes of a Percutaneous Wide-Diameter Bone-Anchored Hearing Implant: A Clinical Evaluation of More than 800 Implants

OBJECTIVE

This study evaluates the clinical outcomes of 807 percutaneous wide-diameter bone-anchored hearing implants (BAHIs) in 701 patients. In addition, it compares patient groups and examines bone conduction device (BCD) usage.

STUDY DESIGN

Retrospective cohort study. Mean follow-up period of 3.8 years.

SETTING

Tertiary referral center.

PATIENTS

All patients implanted with a percutaneous wide-diameter BAHI until December 2020 were included. Patients were divided into age groups, "loading-time" groups, and, if applicable, specific subgroups thought to be at risk for complications postsurgery, e.g., intellectual disability and comorbidities.

MAIN OUTCOME MEASURES

Soft tissue reaction, implant survival, revision surgery, and BCD usage.

RESULTS

In 9.1% of the 5,188 observations of 807 implants, an adverse soft tissue reaction was reported according to the Holgers' scale. Significantly more (adverse) soft tissue reactions were observed in children and intellectually disabled (ID) patients (p < 0.05). Comorbidity subgroups showed no significant differences in soft tissue reactions. Implant loss percentage, including explantations, was 6.2%. Implant survival was significantly worse in patients with ID (14.1%; p = 0.021). Pediatric age, early loading, or comorbidities did not significantly influence implant survival. At least 592 implants (73.4%) were used for bone conduction hearing, of which 65.4% were used daily.

CONCLUSION

Both children and ID patients are more prone to (adverse) soft tissue reactions, ID patients only have a higher risk of implant loss. The rate of implant loss in children seemed to be reduced compared to previous studies and thus more comparable to adults since using wide-diameter implants.

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.

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.

Post-operative infection rates in linear vs. punch technique for bone anchored hearing systems

PURPOSE

This study investigates the post-operative infection rates between two surgical approaches: linear incision and the punch technique for bone anchored hearing systems. Secondarily, it investigates the impact of smoking, comorbid disease, and operative conditions on post-operative skin reactions and infections.

METHODS

A retrospective study was conducted at a single tertiary care institution. A single surgeon completed either of the two techniques on adult patients with mixed, conductive hearing loss, or single sided-deafness. Patients included had at least 6 months follow-up, and were evaluated for preexisting illnesses, perioperative complications, length of surgery, and post-operative complications including infection after surgery. Post-operative soft tissue around the abutment was assessed with Holgers Classification scale.

RESULTS

Fifty-one patients were included in this study, 28 female and 23 males with an average age of 68.8. Thirty-three patients underwent linear incision surgery and 18 had the punch technique. Overall 9 patients (17.6%) had post-operative infections requiring topical or oral antibiotic treatment. Six (18.2%) were in the linear group and 3 (16.7%) in the punch group. There was no statistically significantly difference (p = 1). A multivariate analysis compared age, sex, obesity, DM, operative time, skin thickness, and abutment size to post-operative skin infection rates requiring treatment. Only DM was statistically correlative with infection (p = 0.02).

CONCLUSION

No significant differences in post-operative infections were identified comparing linear incision and the punch techniques. Patients with diabetes had a higher incidence of post-operative skin infections rates.

The Cleating Stitch: An Adjunctive Technique for Percutaneous and Revision Osseointegration Screws

OBJECTIVE

The bone anchored hearing aid (BAHA) has become a widely used and successful option in treatment of conductive and mixed hearing loss, and single sided deafness. Despite improvements in technique and cosmesis, complications remain that can result in implant revision or removal. Herein we describe a unique adjunctive technique, the cleating stitch, in placement of osseointegration screws and examine its impact on complication rates.

STUDY DESIGN

Retrospective case review.

SETTING

Tertiary academic medical center.

PATIENTS

A total of 66 implants in 65 patients (35 men, 30 women) with an average age of 54 years (15-81 yr). Average follow up 10.8 months.

INTERVENTION

All patients underwent BAHA implant placement by a single surgeon between April 2012 and June 2017 using the linear incision or punch techniques with soft tissue reduction and placement of a cleating stitch.

MAIN OUTCOME MEASURE

Main outcome measures include rates of revision surgery, overgrowth, extrusion, and Holgers reaction ≥2. Secondary outcome measures include associations between main outcome measures and outlying factors (obesity, smoking, diabetes mellitus, coronary artery disease, age).

RESULTS

The overall rate of revision was 3%, rate of overgrowth 1.5%, rate of extrusion 1.5%, and Holgers reaction ≥2 10.6%. Overgrowth and extrusion both required revision. Older age was associated with decreased risk of Holgers reaction ≥2 (p = 0.03) with a hazard ratio of 0.95 (confidence interval 0.9-1.0). There were no other statistically significant associations between primary outcome measures and outlying factors.

CONCLUSION

The cleating stitch is an effective adjunctive technique in placement of osseointegration screws associated with low rates of overgrowth and overall revision surgery.

Percutaneous bone-anchored hearing implant surgery: linear incision technique with tissue preservation versus linear incision technique with tissue reduction

OBJECTIVES

To identify differences in skin thickening and soft tissue reactions between the linear incision technique with tissue reduction (LITT-R) and the linear incision technique with tissue preservation (LITT-P).

STUDY DESIGN

Retrospective cohort study.

METHODS

All adult patients who underwent the LITT-R or LITT-P between August 2005 and December 2016 at a large general teaching hospital with a minimum follow-up of 6 months were included.

RESULTS

A total of 83 implants were included using the LITT-R with a median follow-up of 74.0 months. In the LITT-P cohort 58 implants were included with a median follow-up of 16.5 months. Skin thickening was seen in seven implants (8.4%) in LITT-R cohort and 11 implants (19.0%) in the LITT-P cohort in the first 2 years of follow-up (p = 0.024). Skin thickening in need of treatment was registered in 5 (6.0%), respectively, 6 (10.3%) implants (p = 0.100). Moreover, treatment was successful in all cases. A soft tissue reaction (Holgers ≥ 1) was noticed in 28 (33.7%) implants in the LITT-R group compared to 16 implants (27.6%) in the LITT-P group (p = 0.679). An adverse soft tissue reaction (Holgers ≥ 2) was registered in 16 (19.2%), respectively, 2 (3.4%) implants. This difference was significant (p = 0.040).

CONCLUSION

LITT-P has a significantly higher rate of skin thickening and LITT-R has a significantly higher proportion of adverse soft tissue reactions. Nevertheless, combined with the advantages of LITT-P described in other studies, this can be advocated as the preferred technique.

Percutaneous bone-anchored hearing implant surgery: dermatome versus linear incision technique

The objective of this historical cohort study is to identify if there are differences in soft tissue reactions and skin thickening between implantation of the percutaneous bone-anchored hearing implant (BAHI) using the dermatome or linear incision technique. All adult patients who received a BAHI between August 2005 and January 2013 were selected. One surgeon performed all procedures and only the dermatome and linear incision technique were used. A total of 132 patients/implants were included and significantly more patients with risk factors were seen in the linear incision cohort. A soft tissue reaction Holgers ≥1 was present in 18 patients (40.9 %) in the dermatome compared to 36 patients (40.9 %) in the linear incision group. A Holgers ≥2 was noticed in 9 (20.5 %) and 19 (21.6 %) patients, respectively. Skin thickening was described in 14 (31.8 %) and 11 patients (12.5 %) in, respectively, the dermatome and linear incision cohort, which was a significant difference (p = 0.001). Nevertheless, therapeutic interventions were effective. In conclusion, there was no significant difference in (adverse) soft tissue reactions; however, skin thickening was more present in the dermatome technique. In addition, significantly more patients with risk factors were allocated to the linear incision technique. Based on these results, the linear incision is advocated as preferred technique.

Laser-Modified Surface Enhances Osseointegration and Biomechanical Anchorage of Commercially Pure Titanium Implants for Bone-Anchored Hearing Systems

Osseointegrated implants inserted in the temporal bone are a vital component of bone-anchored hearing systems (BAHS). Despite low implant failure levels, early loading protocols and simplified procedures necessitate the application of implants which promote bone formation, bone bonding and biomechanical stability. Here, screw-shaped, commercially pure titanium implants were selectively laser ablated within the thread valley using an Nd:YAG laser to produce a microtopography with a superimposed nanotexture and a thickened surface oxide layer. State-of-the-art machined implants served as controls. After eight weeks' implantation in rabbit tibiae, resonance frequency analysis (RFA) values increased from insertion to retrieval for both implant types, while removal torque (RTQ) measurements showed 153% higher biomechanical anchorage of the laser-modified implants. Comparably high bone area (BA) and bone-implant contact (BIC) were recorded for both implant types but with distinctly different failure patterns following biomechanical testing. Fracture lines appeared within the bone ~30-50 μm from the laser-modified surface, while separation occurred at the bone-implant interface for the machined surface. Strong correlations were found between RTQ and BIC and between RFA at retrieval and BA. In the endosteal threads, where all the bone had formed de novo, the extracellular matrix composition, the mineralised bone area and osteocyte densities were comparable for the two types of implant. Using resin cast etching, osteocyte canaliculi were observed directly approaching the laser-modified implant surface. Transmission electron microscopy showed canaliculi in close proximity to the laser-modified surface, in addition to a highly ordered arrangement of collagen fibrils aligned parallel to the implant surface contour. It is concluded that the physico-chemical surface properties of laser-modified surfaces (thicker oxide, micro- and nanoscale texture) promote bone bonding which may be of benefit in situations where large demands are imposed on biomechanically stable interfaces, such as in early loading and in compromised conditions.