Voice prostheses terminology
Some constantly recurring components in voice prostheses have special names and it is important to know them in order to understand the shape, size information, method of insertion and how to handle complications.
This is the name of the retaining ring that is visible in the trachea when the prosthesis is in place. It is bigger on indwelling prostheses than on non-indwelling ones to prevent the prosthesis from dislocating into the esophagus. The retaining tape of the prosthesis is often applied to the tracheal flange and the shaft length printed on it.
Is the name for the retaining ring that fits in the esophagus and which prevents the prosthesis from dislocating into the trachea. It is also usually bigger in indwelling prostheses than in non-indwelling ones.
Different types of valve (flap valves, ball valves, duckbill valves, magnetic valves) are used in voice prostheses. The flap is the most frequently used valve type. The valve makes sure that the esophagotracheal fistula is safely closed when eating and drinking. The valve or valve bearing are often x-ray proof and so can be found radiologically, if the prosthesis is lost. Voice prosthesis valves fail after a certain period of time due to biofilm deposits and/or material fatigue, which means that the voice prosthesis then has to be replaced.
The prosthesis shaft is situated in the esophagotracheal fistula, and supports the valve. Its length is usually given on the voice prosthesis packaging. It should not be much too long, and most certainly not too short. The most frequently used shaft lengths are: 4 mm, 6 mm, 8 mm and 10 mm. The outer diameter of the prosthesis shaft is usually given on the voice prosthesis packaging in French (Fr) or Millimeter (mm). The inner diameter of the prosthesis shaft is largely responsible for the speaking resistance of the prosthesis, and is not given on the packaging. The optimum shaft diameter is currently the subject of scientific discussion.