Pediatric morphometric study to guide the optimized implantation of the Osia^® 2 implant system

Continuous technological advances result in the availability of new bone conduction hearing implants, of which their suitability for pediatric patients is of major concern. The Cochlear^TMOsia^® 2 is a new active osseointegrated steady-state implant system that uses digital piezoelectric stimulation to treat hearing loss. The implant in the United States was approved for patients aged 12 years and above, whereas the CE mark is independent of age, the only requirement is body weight of at least 7 kg. Therefore, further clinical studies are required to assess device characteristics in younger patients. The aim of our study was to perform a morphometric study among 5-12-year-old children, and to develop a surgical protocol for Osia 2 system implantation based on these findings.

We examined retrospectively cranial CT scans of 5-12-year-old patients from our clinical database. We measured the bone and soft-tissue thickness in the region of interest, and the position of the sigmoid sinus. 3D printed temporal bones were also used for planning.

Soft-tissue thickness varied between 3.2 ± 0.5 mm and 3.6 ± 0.6 mm and bone thickness varied between 3.5 ± 1.1 mm and 4.7 ± 0.3 mm. The sigmoid sinus was located 1.3 ± 0.2 cm posterior to the ear canal, and the anterior distance was 4.8 ± 0.9 to 7.1 ± 1.1 mm.

Our morphometric studies showed that patients aged 5-12 have different anatomical dimensions compared to adults, but that implantation of the Osia 2 system is feasible in these patients using an altered implant positioning recommended by our data. The Cochlear™ Osia^® 2 is, therefore, an option for hearing rehabilitation in younger pediatrics.