Using Digital Skills and 3D Printing to Create Wound Simulation Models for Austin Health
By Louise van der Werff and Jasamine Coles-Black
What do you get when you combine Autodesk Inventor, Meshmixer, 3D printing, Lego blocks and silicone moulding? A wound simulation model for nursing students at Austin Health! The following post outlines the step by step process we used to generate a viable research/training product using digital CAD tools for the medical community.
A couple of months ago Paul Mignone and I (Louise), along with Dr Jason Chuen and Jasamine Coles-Black collaborated to create a new training product for the Austin Hospital Clinical Skills Simulation Laboratory. They wanted to create models to simulate a wound or ulcer that extended under the skin, and use those models for nurses during training sessions to practice washing and irrigating a wound cavity, before packing it with gauze.
Prior to the creation of these new moulds, the Simulation Laboratory was using a variety of other models when running their training sessions. However, there was no uniformity in the models used and some did not have a cavity deep enough to be packed with gauze. In addition, some of the previous models were made of polyurethane foam, which, after the addition of Thai sweet chilli sauce as mock “blood”, resulted in perpetually sticky models as they could not be easily cleaned.
Image: A previously used wound simulation model, made from painted polyurethane foam.
The brief was that the model needed to be waterproof and washable, reusable, and the wound cavity had to be irregular, and have an overhang of ‘skin’. They also wanted 10 identical models, so generating these models in a reproducible and cost effective manner was quite important.
After some consideration we decided to use a soft silicone rubber as the model material. All we had to do was create a negative impression of the wound cavity, and cast silicone rubber around it to create the final model.
I was able to use some of the 3D modelling skills I had learnt in the Research Bazaar Autodesk Inventor course run by Paul Mignone and Aliza Wajih to prototype the wound model using the following steps:
I created an underlying flesh layer, and ‘scooped out’ a cavity using sketch, extrude (cut) and bevel tools. I then created a skin layer, which extended past the boundary of the wound bed to create an overhang. Last but not least, I created a new object which represented the negative of the resultant wound cavity. Pretty cool huh?
Image: Forming the ‘flesh’ and ‘skin layers in Autodesk Inventor.
Since wounds aren't generally nice and smooth like engineering shapes, I exported this resultant 3D shape into MeshMixer, and used its 3D sculpting tools to add a little bit of unevenness to the model.
Image: MeshMixer sculpting before and after.
I then printed the shape out on a Makerbot Replicator 2X in ABS plastic, used sandpaper to smooth the surface just a little, and I was ready for silicone casting!
The 3D printed shape was glued upside down onto a flat surface. I then used Lego blocks (highly versatile!) to build up a ‘container’ around the shape to contain the silicone. To make the moulds I used Pinkysil, a very easy to use cast-able bright pink silicone which cures quickly and is relatively soft.
Image: Before and after pouring Pinkysil silicone into the mould container.
After curing, the 3D printed negative was pulled out from the silicone, leaving an impression, which became the simulation wound bed! The ease of this process meant I was able to make 10 identical models relatively quickly.
Image: Close-up of a single resultant wound model, and the 10 identical models.
The models have already been used in a training workshop for second year nursing students, with very positive feedback. The students loved them, they were an enjoyable teaching tool, and a great improvement to previous models. They were also easy to clean (they could simply be rinsed off and put away at the end of the session), and having 10 models in a session meant each student could follow through the steps at the same time, rather than having to rotate.
Image: The wound models, stuffed with irregular wound material for simulation training.
If you have any questions at all about this process, please don’t hesitate to get in touch. You can email me at [email protected] and tweet me @LouWerff.
