Influence of cable tension on the vibrancy of the FMT of the Vibrant Soundbridge​

The Vibrant Sound Bridge​ (VSB) implant system consists of a receiver/stimulator, a gold wire cable and the Floating Mass Transducer​ (FMT) stimulator. The FMT is attached by a coupler to middle ear structures, including the short incus process (SP). With this type of attachment, the FMT cable often is in contact to the bone of the skull base, potentially putting pressure on the FMT and affecting its ability to vibrate. The aim of this study was the clinical-experimental evaluation if a cable pre-tensioning has an influence on the vibrancy of the FMT of the VSB.

In addition to the dissection of the middle ear, an opening was made in the base of the skull on human temporal bones. After the FMT‘s placement via an SP coupler, the cable was passed through the opening to an electronic scale, which could be used to exert pressure on the cable using a movable table. Subsequently, acoustic stimulation was applied via the tympanic membrane and electrical stimulation via the FMT with different frequency bands and different cable pre-tensions. The vibrations were recorded and evaluated on the stapes footplate using laser doppler vibrometry.

Acoustic stimulations showed consistent derivations for all pre-tensions, indicating normal middle ear function. Electrical stimulations indicated a shift in vibrancy from the middle frequencies to the high frequencies with increasing pre-tension.

This experimental model for the evaluation of the influence of a cable pre-tension of a VSB showed that increased cable pre-tension has an influence on the effect of electrical stimulation of the FMT.

Conflict of Interest 

The author declares that there is no conflict of interest.

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Artikel online veröffentlicht:
24. Mai 2022