Patient Outcomes in Magnet-Based Implantable Auditory Assist Devices

Abstract

Magnet-based implantable auditory assist devices (MIAADs) are a recent development in bone-anchored hearing devices. This report increases the number of children studied with specific outcome criteria and provides detailed solutions to avoid device use difficulties in other centers considering this device. To assess hearing thresholds, use rates, and complications in children implanted with a MIAAD for conductive hearing loss. Retrospective analysis of children implanted with an MIAAD at an ambulatory care quaternary referral center since the Food and Drug Administration approved the Sophono device (Sophono Inc) for use in the United States (May 2011 through January 2013). Ten pediatric patients were implanted for conductive hearing loss (14 ears; mean age at implantation, 9 years [range, 3.8-17.2 years]). Diagnoses included aural atresia (n = 7) and chronic ear disease and cholesteatoma (n = 3). Implantation of MIAAD and management of skin complications. Demographics, hearing thresholds, use rates, and complications were assessed. After fitting with the magnetic baseplate and sound processor, the mean (SD) aided pure-tone average was 20.2 (6.0) dB hearing level (HL), with a mean (SD) functional gain of 39.9 (12.4) dB HL. There were no surgical complications. Negative outcomes were assessed following fitting of the sound processor. The skin complication rate was 35.7%, including skin breakdown (n = 2) and pain and erythema (n = 5), which resulted in decreased use of the device for these patients. Intervention included decreasing the magnet strength, graduated wearing schedule, antibiotic ointment, barrier protection, and reoperation for well widening with Alloderm (LifeCell Corporation) placement. Patients without skin complications are consistent users of their device, with an average daily use of 8 to 10 hours. The MIAAD device has equivalent levels of hearing restoration to other previously described methods of intervention for children with conductive hearing loss. This early report indicates high rates of skin difficulties and a need for improved methods of implantation, magnetic baseplate fitting, and device use. We suggest decreased magnet strength at the initial fitting, a graduated wearing schedule, caution with patients who have a history of skin issues from a bone-anchored hearing aid or multiple surgical procedures, and parent counseling regarding potential skin irritation.