Influence of bone bed on the output performance of a new transcutaneous bone conduction implant using objective measurements

Introduction 

Transcutaneous bone conduction devices (BCDs) are alternatives to percutaneous bone anchored hearing systems. We compared the output performance of a novel semi-implantable BCD (Sentio, Oticon Medical) to an established percutaneous bone anchored hearing system (Ponto 3, Oticon Medical) using cadaver heads and showed that the output performance improves by placing the transcutaneous devices closer to cochlea. Here, the influence on the performance of the Sentio after creation of a bone bed at the stimulation position was investigated.

Methods 

The transcutaneous Sentio was initially implanted at about 20 mm inferior-posterior to the ear canal opening behind the pinna on the mastoid bone surface without any bone bed in 5 human cadaveric heads. The ipsi- and contralateral cochlear promontory (CP) vibration in response to BCD stimulation was measured using Laser Doppler vibrometery. Afterwards, the bone was flattened by drilling an approximately 3 mm deep bone bed that fitted the Sentio, and the CP vibration was measured after placing the Sentio and results were compared.

Results 

Irrespective of response side at frequencies below 700 Hz, the average relative CP velocity magnitude difference was in the -1 to -2 dB range indicating a minor benefit having a bone bed. At the transducer resonance frequency (around 1 kHz) and 5 –6 kHz the relative magnitudes were positive, indicating a slight negative effect of placing the implant in a bone bed. However, no significant effects of the bone bed were found.

Conclusion 

The results showed that drilling a bone bed for the placement of the Sentio transducer does not improve the output performance.

william demant foundation and Oticon Medical

Publication History

Article published online:
24 May 2022