It started with the story of a baby girl who was born with a hip problem (“hip dysplasia,”). Her “treatment,” which began at three months, involved being hung upside down so that her leg would pull out of its wrong position – something so painful, she had to be given morphine.
Next in this six month regimen, her legs were put into plaster casts, with a wooden bar from left foot to right foot, to keep her from moving. As she grew, every six weeks she went back into the hospital to have the old casts cut off, and to have new casts and a bar put on.
In the end, the outcome was successful. But not surprisingly, her dad wondered if there was something better.
Now, Ron Taylor and his colleagues at Torc2 (Coventry, England) have come up with that something better: a novel blend of petroleum-based wax and thermoplastic for casts, splints, even the connectors for prosthetic limbs.
They started with thermoplastic, because it softens when heated, but becomes solid when cool. This particular thermoplastic blend can be warmed on a person’s body, in just the spot where a cast is needed, for example. Then while it is soft, the doctor can shape it to a perfect fit. And when it cools down, that plastic cast is solid and sturdy and ready to protect that broken arm or leg.
And why the wax? Because heating thermoplastic on a person’s arm or leg might burn the skin. Blending in that wax, means the plastic can be warmed and softened at a lower temperature that is safe for patients, while still allowing it to be molded precisely to where it is needed.
These high-tech thermoplastic blends are made with polyvinyl acetate, which is derived from ethylene, and can be heated, shaped and cooled to solid, over and over again – so adjustments as a baby girl grows, for example, don’t require returning over and over again to an operating room. And reshaping, instead of replacing casts, will not only be simpler to do, it will be much less expensive for patients as well.
Thermoplastic blends make the new treatments possible, and what makes thermoplastic blends possible, are petrochemicals derived from petroleum and natural gas.