Material Parameters and ESEM Characterization of Functional ENT Prostheses During Ongoing Degradation

Voice prostheses and tracheal prostheses are functional prostheses that are implanted to copy a natural function. Voice prostheses are implanted in patients who have had their larynx removed for medical reasons. With a voice prosthesis, fast voice rehabilitation is possible. The prosthesis generates the voice only indirectly. It makes possible an airflow that can cause vibrations of the entrance musculature and mucous membrane of the oesophagus. It is a pharyngo-tracheal shunt valve. Because of the overpressure in the trachea, air streams into the oesophagus or the low pharynx area. On the other hand, the passage of saliva and undigested food into the trachea from the oesophagus is prevented because of the valve effect. Perfect valve function is necessary for correct functioning: dysfunction necessitates a prosthesis change. There is a range of products on the market that differ mainly as far as the valve is concerned. The material of choice is silicone rubber. Polyurethane has also been tested as a material. Details of clinical use are given in [1–3].