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Length measuring devices

Length measuring devices are used to measure the length of the shunt. The defined measurement should be the same as the shaft length of the prosthesis being used. If in doubt, always used the next prosthesis in length!

Length measuring devices are made by several manufacturers. Some of them are shown in the following, although this selection is by no means exhaustive.

Blom-Singer® Voice Prosthesis Sizing Device (measuring prosthesis). The sizing prostheses (1) are constructed like a Blom-Singer Duckbill prosthesis, but without the valve slit. They are made of soft silicone, and are available in a diameter of 16 Fr. (5.6 mm) or 20 Fr. (6.7 mm). They are attached to an insertion aid (2) and inserted in the shunt.
The length scale (3) in mm is on the prosthesis shaft. The measuring prosthesis can be sterilized, whereas the insertion aid is disposable!
The Provox® measuring device works like a caliper. The scale in mm is on the bar (1). A soft replaceable silicone wing (2) is attached to the end of the bar. This is inserted in the shunt as far as the esophagus. The bar is then drawn back gently until resistance is felt. If the caliper is now pushed as far as the tracheal mucosa, then the length of the shunt can be read on the bar scale. The entire instrument can be sterilized.
The fistula measuring device by Tracoe also works like a caliper. Instead of having a wing at the tip, though, it has a thin silicone disc (1). The entire instrument can be sterilized.

Measuring the shunt length

The display of the correct shunt length measurement is indicated on the shunt model with the Blom-Singer® measuring prosthesis as 16 Fr. diameter. Other measuring devices work in the same way

First, the measuring prosthesis (1) is hooked safely onto the insertion aid (2) to prevent it from falling into the trachea
The measuring prosthesis is now inserted in the shunt through the tracheostoma and pushed into the esophagus. The insertion aid can be tilted up or down slightly to make it easier to push the measuring prosthesis safely into the esophagus
The measuring device is now pulled back gently until the thin flange (1) hooks onto the fistula and a resistance is felt
On the tracheal side, the smallest but still clearly legible millimeter figure is indicated at a gentle pull. This is the correct shaft length for the voice prosthesis to be used. If the shunt is narrow, angled or very long, then the insertion tool can be removed after the measuring prosthesis has been pushed in, and it can then be secured with a clamp. This makes it easier to position the measuring prosthesis