The folks at Vestibular First have provided instructions on how to make your very own
fluid filled vestibular model. This model is enlarged, but anatomically accurate, and
allows patients as well as healthcare providers to better understand the semicircular canal
fluid dynamics as well as how inner ear crystals respond to gravity when displaced in the canals.
The model, once constructed, is 5.3 inches tall, 7.9 inches wide, and 7.5 inches deep.
The tubings contain mineral oil and crushed rock which mimic
otoconia movement and response to gravity in a realistic manner.
You can also purchase a fully constructed model at vestibularfirst.com
First, 3D print the vestibular model. See the description box
for links to download the free 3D printer files.
Measure out and cut clear tubings to represent the semicircular canals.
The anterior and posterior canals should be 25 cm long whereas the horizontal canal should be 21 cm.
Fill 3 end caps with a sealant of some sort and leave a small convex surface over the end
to simulate the profile of the cupula. Fill the entire cap by starting at the
bottom and working your way to the top. Be careful not to allow any
sealant to stick to the outside parts of the end cap or it will not seal correctly.
Insert 1 cupula plugged end cap into each of your cut tubes. You should have one side open
on each tube when finished with this step. It is not easy to insert the end cap into the tube.
It is recommended to use both hands and firmly press the tubing into the end cap using your
body weight. A large rubber band wrapped around the tubing makes this easier to accomplish.
Fill the tube with approximately 4 mm of crushed stones. You
can use different colors for each tube. Here, crushed turquoise was used for the
blue stones. Crushed malachite for green. Crushed red coral for red.
Over a sink, fill the tube with mineral oil about 90% full.
You will notice there are small air bubbles trapped under the stones and on the
walls. Gently tap the tube to help the air bubbles rise to the top. You may have to do this several
times before they all float to the top. Stand the tube upright to help move the process along.
Bend the tube approximately in half to create a crease.
This step is important to prevent too much pressure from building up in the tube when
sealing in the last step, so don’t skip it! Next, completely fill the tube and hollow
end-cap with mineral oil. Always check to make sure no air bubbles are present.
Carefully bring the end cap and tube together at an angle. Make sure the oil does not become
concave in either the end cap or tube to prevent air from being introduced.
Press the end cap partially into the tube. Here I used the sink’s overflow drain to help stabilize
the tubing to help press the end-cap in. Once you’ve confirmed there are no air
bubbles in the tube, release the tube bend and firmly press the end cap fully into the tube.
Once you have sealed all of the tubes and there are no air bubbles,
use soap and water in a sink to wash the tubes and remove any residual oil from the outside.
Glue or adhesive tacky dots as shown here can be used to attach the tubing to the vestibular model.
The vestibular side of the tube is deeper than the ampulla side and you should not
see the hollow end cap tip. The cupula side using plugged end-caps will show a
small part of the end cap as well as the convex sealant you added earlier.
Make sure you affix the plugged end-cap cupula side of the tube into the wider ampulla side of
the model or you will not be able to replicate the anatomy of the inner ear correctly.
To reiterate, you can also purchase a fully constructed model at vestibularfirst.com.