Scoliosis could be treated in the future with a lightweight 3D-printed back brace that feels how effectively it fits patients, an Anglo-American team of researchers claims.
Scoliosis is a form of spinal deformity that affects about three percent of the population, often between the ages of 10 and 15. It can be corrected in younger people by a back brace, which is worn until the child stops growing.
Back brace treatment is effective but can be uncomfortable and requires a time-consuming process of trial and error to find the best fit for each patient.
Now, engineers and medics from the UK and the United States have combined polypropylene with carbon nanotubes to create a cellular material capable of sensing the amount of strain (and stress) it experiences during use.
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The researchers said this material could be used to create a “smart” brace that detects the pressure exerted on the human body, allowing better adjustment of the brace and making the treatment process more comfortable.
In a paper published in ACS applied materials and interfacesThe team led by Glasgow University describes how the carbon nanotubes, placed by random polypropylene copolymer, gave it the ability to form an electrically conductive network across its structure.
The team used 3D printing to create grid-like structures from the material and subjected them to static and cyclic loads while measuring how the smart composite’s electrical resistance change under load.
This measure of the material’s changing piezo resistance can help create a smart brace by showing clinicians which parts of the body are exerting the maximum pressure on the brace.
Their tests showed that after 100 cycles of loading and unloading, the material retained its ability to sense the tension experienced by the material, suggesting it could be smart enough to make it suitable for use in a back brace.
Dr Shanmugam Kumar, van James Watt School of Engineering at Glasgow University, is the corresponding author of the article. Colleagues from Texas A&M University, Massachusetts General Hospital and the Massachusetts Institute of Technology also contributed to the study.
In a statement, Dr. Kumar: “Scoliosis is a painful and debilitating condition, and while the current generation of braces is better than ever, there is still a lot of room for improvement.
“The self-sensing material we’ve developed has great potential to deliver those next-generation improvements. What we hope to see is a future where scoliosis patients can be individually assessed by a doctor and have a 3D-printed brace produced that is unique to their condition.
“Then, after a few weeks of wearing, they can return to their doctor and use the reading from the piezoresistive voltage sensing bracket to adjust it to make it even more effective, without the trial and error that clinicians have to do.” trust at this point.
“That could help patients benefit from more precise adjustments to brace stiffness in different directions, better data to inform the optimal timing and manner of braces adjustments. That would make them a potentially significant improvement over conventional rigid struts made from passive materials through conventional manufacturing approaches. Cellular designs of smart composites make the braces lightweight while also offering tunable mechanical and functional attributes.
He added: “We’re eager to explore the real-world applications for this technology, and we’re in the early stages of talks with doctors here in the UK and a medical device company to look at the possibility of testing these braces in a clinical environment.”
The team’s paper, entitled “Synthesis and characterization of carbon nanotube doped thermoplastic nanocomposites for the additive manufacturing of self-sensing piezoresistive materials,” is published in ACS applied materials and interfaces† The research was supported by funding from the Abu Dhabi National Oil Company.