Prototyping a medical device for developing countries with high resolution 3D printing

Women in the developed world take routine tests such as pap smears for granted. But in many parts of the world, tools and equipment are not available for even simple analysis. Consequently, 88% of all cervical cancer is found in the developing world where the tests are not available. With over 250,000 deaths per year, cervical cancer creates an economic burden of almost $300 million per year in parts of the world that can least afford it.

Working with Jhpiego, a John’s Hopkins University affiliated Non-Government Organization focused on improving women’s health, Momo Scientific developed an elegant solution to the problem. The CryoPop is a low-cost medical device that uses dry ice for the treatment of cervical pre-cancerous lesions. The concept is similar to freezing warts off the skin. With the easy availability of CO2 cartridges from the soda industry, costs are low.

3D Printed cervical lesions device

3D Printed Medical Device for freezing cervical lesions

The CryoPop obviously is less expensive than the higher costs of cancer treatment and lost wages. But the real beauty of the solution for a developing nation is that properly trained nurses or midwives can detect the lesions and conduct the simple procedure, further reducing cost of medical care by a physician.

CryoPop’s Project Manager, Marton Varady, built his original prototypes using a 3D printer in the Bioengineering Lab at Johns Hopkins. But as the medical device design developed, he needed higher precision. The 3D printer only had tolerances of 10 -15 thousandths and the support material had to be manually removed.

Hoping that mechanical machining might do a better job, the prototyping task was sent to a service contractor. Here the problem was that the machine could not drill holes deep enough for the design requirement. The vendor finally hit upon the idea to make the part in two pieces in order to reduce substrate thickness for the hole drilling.

But Varady remembers: “Having to glue the parts back together created an entire new set of problems for the design’s robustness. And so that was not an optimal solution. Plus the material resulted in a porous device and it affected how the snow [the actual cryogenic element] from solid CO2 was forming”.

Hearing about higher resolution 3D printing, Varady found Potomac Photonics, Inc. that had a much higher resolution 3D printer. Varady comments, “The resolution of this 3D printer was much higher than what we had in our onsite lab. Working with tolerances in the 1 – 2 thousandths range gave us the parameters we needed to fulfill the design requirement. Plus, we could make the entire part in one piece which increased robustness.”

Currently, the CryoPop is between prototyping and animal trials. When asked if he’ll continue to use 3D printing, Varady brought up some concerns. He is “not sure if the structural integrity from 3D printed parts is proven enough yet for human trials. I need to conduct more tests to verify this before we decide on final production processes. I am also not sure what the FDA thinks about 3D printing.”

That’s an interesting question, that demonstrates while 3D printing is often the technical solution of choice for prototyping, we are still learning how to bring this exciting new technology into the mainstream of manufacturing, at least for medical devices. At the moment some of the best solutions I’ve seen integrate 3D printing with other manufacturing processes, such as laser or CNC machining. As Varady put it, “3D printing can’t always do everything we need, but it is a great tool and has solved some tough problems in our project. It really helped move us toward saving women’s lives!”