A new active bone-conduction implant: surgical experiences and audiological outcomes in patients with bilateral congenital microtia

Purpose First-generation bone bridges (BBs) have demonstrated favorable safety and audiological benefits in patients with conductive hearing loss. However, studies on the effects of second-generation BBs are limited, especially among children. In this study, we aimed to explore the surgical and audiological effects of second-generation BBs in patients with bilateral congenital microtia. Methods This single-center prospective study included nine Mandarin-speaking patients with bilateral microtia. All the patients underwent BCI Generation 602 (BCI602; MED-EL, Innsbruck, Austria) implant surgery between September 2021 and June 2023. Audiological and sound localization tests were performed under unaided and BB-aided conditions. Results The transmastoid and retrosigmoid sinus approaches were implemented in three and six patients, respectively. No patient underwent preoperative planning, lifts were unnecessary, and no sigmoid sinus or dural compression occurred. The mean function gain at 0.5–4.0 kHz was 28.06 ± 4.55-dB HL. The word recognition scores improved significantly in quiet under the BB aided condition. Signal-to-noise ratio reduction by 10.56 ± 2.30 dB improved the speech reception threshold in noise. Patients fitted with a unilateral BB demonstrated inferior sound source localization after the initial activation. Conclusions Second-generation BBs are safe and effective for patients with bilateral congenital microtia and may be suitable for children with mastoid hypoplasia without preoperative three-dimensional reconstruction.