Parameters to Estimate the Implantability of a Semi-Implantable Bone Conduction Device in Children and Adolescents in Relation to Geometric Changes of the Actuator

Introduction Preoperative planning for a semi-implantable bone conduction device (SIBCD) is crucial in children and adolescents. Geometric changes of the new version of the most common SIBCD (Bonebridge, MED EL GmbH – BB) should enable higher implantability due to its flatter actuator.

Methods Retrospective analysis of 136 CT-scans of 0- to 20-year-old consecutive patients with evaluation of demographic parameters, radioanatomy, and head diameter by applying a planning software. Implantability was investigated for all age groups at the traditional mastoidal localization and 2 alternative sites, retrosigmoidal, and parietal. Implantability prediction by means of different parameters was calculated.

Results A significant higher implantation rate was observed with the new device for all sites and age groups. The age group of 6- to 8-year-olds (n=19) had the most striking difference with a 58.1% implantability rate with the new device without spacer (80% with spacer) at the mastoidal localization, whereas none with the old implant. Whenever implantation was deemed impossible at the mastoidal site, it was impossible at the alternative localizations, as well. Head diameter was the most predictive parameter regarding all implantation sites (mastoidal: p=0.030; retrosigmoidal: p=0.006; parietal: p<0.0001), age for the mastoidal (p<0.0001) and retrosigmoidal (p<0.0001), and gender for the parietal site (p=0.001).

Conclusions: Age, gender, and especially head diameter aid in estimating the implantability in the youngest patients and may be a novel tool to assist in surgical planning. The geometric changes of the actuator lead to higher implantability rates in all age groups and localizations with decreased requirement for spacer application.

Conflict of Interest Der Erstautor weist auf folgenden Interessenkonflikt hin Reisekostenübernahme von MED EL, GmbH und Cochlear Deutschland GmbH & Co. KG.

Publication History

Article published online:
24 May 2022