Abstract： Background: Baha Attract System was designed as non-skin penetrating bone conduction implant to minimize skin complication. However, there were insufficient studies on its long-time acoustic outcome and safety in microtia patients with auricle reconstruction surgeries, who have thinner retroauricular subcutaneous layer and theoretically vulnerable skin at the implant side. Objectives: To analysis the long-term hearing performance and soft tissue complications of Baha@ Attract System in microtia population. Study Design & setting: A prospective cohort study at single tertiary referral center. Patients: Twenty Mandarin-speaking patients with congenital bilateral microtia who were underwent Baha@ Attract implantation with or without auricle reconstruction surgeries simultaneously. Main Outcome Measure(s): Comparative analysis of audiological test results including hearing thresholds and speech recognition in quiet and in noise were pre- and post-operatively performed. subjective benefit as measured with the SSQ Scale. Soft tissue outcomes were monitored and documented. Results: The mean follow-up time was 36.11±3.30 months. Significant and stable improvements in hearing threshold and speech understanding in noise and quiet were demonstrated with aided condition. Subject evaluation revealed high level of patients’ satisfaction with the amplification in all the subscales. Adverse events including skin necrosis increased after one year post-operatively. Soft tissue evolution including sin thinning, erythema, epidermis atrophy, soft tissue atrophy, skin necrosis was seen or once developed in most of the participants. However, prevalence of severe soft tissue complication was not higher to non-microtia population. Conclusions: Baha@ Attract System provides favorable and stable hearing improvements for microtia patients. Combining plastic surgeries with implantation will not increase the prevalence of soft tissue complication. However, long-term soft tissue problems should be highly aware of even after one year post implantation. Key words: Baha Attract, microtia, hearing, soft tissue, skin necrosis

Purposes: To evaluate the instant auditory benefit of an adhesive bone conduction hearing aid (ADHEAR) on children with bilateral congenital microtia, especially the sound localization ability under unilateral and bilateral fitting. Methods: Twelve patients with bilateral congenital microtia aged from 6 to 17 were included in this study. Pure tone threshold under sound field, speech recognition threshold in quiet and sound localization abilities were tested and compared before and after wearing the device. The pure tone threshold test was additionally repeated for two different wearing method – adhesive or fixed with softband; the sound localization test was repeated for both unilateral and bilateral fitting. Correlation analysis was then conducted to find the influencing factors of sound localization improvement. Results: Significant auditory improvement were found: the average pure tone threshold (PTA) reduced by 24.8 (adhesive) and 27.3 dB HL (softband), with no significant difference between the two wearing methods. The speech recognition threshold also improved by 29.0 dB. As for sound localization abilities, no significant improvement was found under unilateral fitting; but half (6 of 12) of the patients were notably benefited from bilateral fitting. The improvement was found to be strong correlated with the patients’ unaided sound localization ability – those with poorer localization abilities tends to benefit more. Moreover, it was found that the sound localization improvement was also negatively related with the malformation degrees of the patients’ head. Summary: ADHEAR affords significant auditory benefits for children with bilateral congenital microtia, in terms of sound and speech perception. The sound localization abilities could be partly improved instantly by bilateral fitting, and the improvement is related with factors such as adaption and skull malformations.