Treatment of the atretic ear with round window vibrant soundbridge implantation in infants and children : electrocochleography and audiologic outcomes

OBJECTIVE: To evaluate the long-term outcomes of the first 5 infants and 9 children with congenital aural atresia (CAA) who had undergone hearing rehabilitation using the MED-EL Vibrant Soundbridge with intraoperative assistance of electrocochleography (ECoG) for optimal fitting of the floating mass transducer (FMT) on the round window (RW) membrane. STUDY DESIGN: Tertiary referral medical center; retrospective case series. PATIENTS: Infants and children ranging in age from 2 months to 16 years with a moderate-to-severe conductive or mixed hearing loss with CAA. For comparison, the study population was divided into 2 groups: older children (≥5 yr of age; 5 patients) and younger children/infants (<5 yr of age; 9 subjects) who were submitted to different audiologic tests appropriate for their age and general condition. INTERVENTION: RW implantation. MAIN OUTCOME MEASURES: Compound action potential threshold and amplitude were assessed as a function of different methods for stabilizing the FMT on the RW. Pure tone audiogram at 0.5, 1, 2, and 4 kHz, free-field speech testing (older children), bone conduction and free-field auditory brainstem response (ABR; younger children and infants), intraoperative and postoperative complications, and FMT displacement or extrusion rate. RESULTS: Statistically significant differences were observed with ECoG recordings between pre- and post-FMT-RW membrane optimization with fascia and cartilage (p < 0.001). Significant improvements were observed in speech perception and pure-tone and ABR threshold, immediately after surgery and at follow-up intervals (12-65 mo) in children and infants (p < 0.01). No complications or instances of device extrusion were observed. CONCLUSION: Infants and children with moderate-to-severe conductive or mixed hearing loss, not suitable or unwilling to accept Bone-Anchored Hearing Aids and who would not tolerate traditional bone and air conduction hearing aids, obtain substantial benefit with the FMT-RW implantation procedure. Intraoperative ECoG is of significant help in achieving the best FMT-RW fitting.