Histologic Evaluation of Soft Tissue Integration of Experimental Abutments for Bone Anchored Hearing Implants Using Surgery Without Soft Tissue Reduction

Abstract

Objective: The protocol for bone-anchored hearing implants (e.g., Baha A ) 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) hydroxyapatitecoated 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.

A Minimally Invasive Technique for the Implantation of Bone‐Anchored Hearing Devices

“…Subsequently, Hulcrantz 12 showed that no soft tissue reduction did not compromise implant stability or surrounding soft tissue status following BAHA implantation. This has been further validated by the histologic findings of Larrson et al, 13 who found limited or no signs of inflammation in the soft tissue surrounding the abutment when no soft tissue reduction was performed with BAHA implantation in sheep. Our technique takes a further step with even less manipulation of the soft tissue surrounding the implant.…”

Cutaneous Complications in Osseointegrated Implants: Comparison Between Classic and Tissue Preservation Techniques

“…3 This surgical technique is based on a new generation of abutments, whose main difference is their greater length in order to adapt to the thickness of the patient's skin and better integration with the subcutaneous tissue. 8 Although there are still a few published articles on this new technique, those that there are, describe very good results. In their series, Husseman et al 9 found 34 cases of BAHA where only 15% presented a reaction which was higher than a Holger's grade 2, but they do not compare with a reference group.…”

A Five-Year Follow-up on the Osseointegration of Bone-Anchored Hearing Device Implantation Without Tissue Reduction

“…Additionally, the skin thinning and hypertrophic scar tissue could reduce blood transport, thus potentially hampering the local immunological responses of importance in the healing procedure and in peri-implant infections (21). Recent studies indicate that the omission of skin thinning may be preferable to any reduction of the subcutis, as it does not augment skin problems clinically or histologically and it allows for a better aesthetic outcome (1,4,6,22). These results were reinforced in the current study, as no increased rate of skin-related problems was observed in the test group 5 years after implantation.…”