PuzzleCast: speed up healing by removing modular cast piece by piece
Having your arm in a cast for months helps your broken bones heal. But these long periods of immobilization can harm otherwise healthy joints and muscles – and you end up with stiff joints and other post-cast complications.
So, for a biomedical engineering course at the University of Virginia, four students decided to construct a cast that would free up an arm to be more flexible while other parts of the arm that are still recuperating can remain concealed.
They created a modular cast called PuzzleCast. It secures the arm like a conventional cast, but it can be disassembled one piece at a time as the bone heals, limiting the harm casts cause. Popular Science reports.
Freeing up the arm to make specific movements one by one builds flexibility, increases blood flow to muscles, and reduces muscle atrophy – this then reduces the length of physical therapy after the cast is removed by as much as half.
- The students wrapped clay around their arms to determine the best shapes and positions for the pieces.
- One team member was put in a regular cast, and her range of motion was measured. This was compared with that of their plastic prototypes.
- The resulting cast is assembled by putting the heat-moldable plastic in hot water, shaping the cast around the patient’s arm, and snapping in rivets to fasten the pieces. (The application time is about the same as for a standard cast.)
- To take a piece off, doctors just remove the rivets.
PuzzleCast has 6 removable pieces (pictured):
- 2 pieces brace the forearm and hand, keeping the broken limb stable.
- The rest restrict each of the lower arm’s 4 movements: the bending of the elbow and the up-down, side-to-side, and twisting of the wrist.
The team received a $10,000 grant last year from the National Collegiate Inventors and Innovators Alliance to test their device on people wearing one for several weeks.
Their next step is to license the design to a manufacturer that can do clinical trials, develop more sizes and a version for legs, and bring the PuzzleCast to patients in the next 3 years.
It costs $10,300 to develop. You can watch a video of PuzzleCast here.
The device is one of 10 winners of the 2012 PopSci Invention Awards.
Image via PopSci