Learning Objectives: To become aware of the clinical differences of soft tissue preservation surgery with a HA-coated abutment in comparison to the outcomes using the conventional technique.
Introduction: Soft tissue preservation using a hydroxyapatite-coated abutment may lead to a reduction in complications in percutaneous bone conduction hearing implant surgery. In this open multi-center, randomized(1:1), controlled clinical trial, eligible subjects were assigned to receive the conventional intervention, a titanium abutment (Cochlear™ Baha® BA300) with soft tissue reduction, or a new intervention, a hydroxyapatite-coated abutment(BA400) with soft tissue preservation. The primary outcome was a combined endpoint which included the secondary outcome measures pain, numbness, peri-abutment dermatitis and skin thickening/overgrowth.
Results: 106 subjects were randomized. The difference between the groups after one year of follow-up as measured by the primary efficacy variable was not statistically significant(p = 0.12) in the ITT population(n = 103), but was statistically significant(p = 0.03) in the Per-protocol population(n = 96). It showed an advantage for the test group, with over twice as many subjects(29%) with none of these important medical events during the first year compared to the control group(13%). Secondary outcome measures, such as surgical time (15 vs. 25 minutes, p < 0.01), numbness(90% vs. 69% of subjects experienced no numbness at one year, p < 0.01), neuropathic pain (mean score at 3 months, 1.06 ± 0.25 vs. 1.70 ± 1.53, p = 0.015) and the overall opinion of the esthetic outcome were favourable for the test group. Five abutments with tissue overgrowth had to be changed in the control group versus one in the test group. No significant differences existed in the occurrence of peri-abutment dermatitis(Holgers index). One implant extrusion was recorded in each group.
Conclusion: Soft tissue preservation with a hydroxyapatite-coated abutment leads to a statistically significant and clinically meaningful reduction in numbness, neuropathic pain and surgical time, and improves cosmetic outcomes in comparison to soft tissue reduction surgery with a titanium abutment.
