Your ideas on how to make casts for broken bones?

[teoman]

I found this to be an interesting idea:
http://www.wired.com/2013/07/is-this-ca ... ken-bones/


As i do a lot of stuff like motorbike riding that will probably get some of my bones broken at some point.. i was thinking it may be a good idea to print some casts in advance. Any ideas on how one would one go about this?

Is 123D and the like up to the task yet?

Thanks in advance.

[RegB]

I am going to drag out the old saw; Such problems are better avoided than solved.

Dainese and others make excellent road armor.

[teoman]

Indeed, not braking any bones is a preference. And i do have a lot of gear to avoid that.

But if I wanted to model body parts or scan objects what are you guys using?

[Captain Starfish]

Get one of those extruders-in-a-pen (3doodler, etc), have a teaspoon of cement in your Milo and draw the structure straight onto your bare skin. [img]http://emo.simonlockwood.net/comando.gif[/img]

Kinect style jobbie with some cleaning up afterwards? Dunno whether you'd want to force a fractured, swollen limb into the shape of your before-broken arm or make something to fit at the time and remake to suit as the swelling dropped.

[RegB]

I suppose you could use the old style "plaster" cast and cut it open once it is dry.
A forearm or lower leg cast, even a wrist cast would be WAY too big for our printers - at this time, next model year's will probably be BFC (bigger, faster, cheaper).

[Captain Starfish]

Depends - if you printed in sections and glued them together (assuming it was strong enough)...

I suspect teoman's query more relates to how we'd get the correct shape into the model to generate the cast.

I was wondering the same thing about a year ago after a ute changed lanes into me on the freeway at 100km/h and the short flight afterwards landed me with a broken foot. First proper broken bone and the plaster cast is horrible - I ended cutting the temporary one off because it was chafing something fierce, the fibreglass one was better but one of these voronoi structures would have been heaven after the first week or two.

[jesse]

PLA plastic can be printed, heated using water, and molded to make a cast by pressing it against the area.

[BrianC]

You would have to use a scanner to get the best fit. Im sure you could use a kinect and even build a device that rotates it around your arm/leg to get good results. The problem with printing before a break is you lose the ability to add reinforcement to the break area specifically. Also if you gain/lose weight from print time to fracture time it won't fit as well. Also I dont think trying to heat form pla to a just broken limb would be a good idea.

[teoman]

What about the 123d stuff and an iphone?

[BrianC]

As long as it provides a good enough model to create the cast around then it should work.

[Jimustanguitar]

I agree with BrianC and Teoman... scan your body know and begin the cyborg conversion early

Just print a whole body cast and cut out sections here and there as needed

[teoman]

Just wear it all the time so you do not brake the bones in the first place...

Ok, so how do i print artificial joints? Anyone know how i can transform MRI images to stl?

[626Pilot]

Just one little problem - you have to squeeze your hand to the point of injury and extreme pain to get it past the wrist. It would be like trying to put on handcuffs that are already closed and locked. Here is how I'd do it:

• Fix the limb in place and scan it
• Clean up the scan and turn it into a fancy Voronoi (latticed) object
• Slice the scanned object in half along the length of the arm, cutting it into two halves: When the arm and hand are laid flat on a table, one half will cover the top of the arm and the other half will cover the bottom
• Join the halves by adding hinges to the outside aspect (pointing away from the centerline of the body) and snap-together contact plates to the inside aspect (pointing towards the centerline of the body)
• There are no metal fasteners at all, so the hinges should be beefy and printed out of some tough plastic
• One of the halves should have a flap (perhaps printed with rubber, or fabric sewn into place) that reaches over the gap between itself and the other half, in order to prevent skin getting pinched in the cut when the cast is closed around the arm
• Add some mounts and guides for straps

3D print, clean, lubricate the hinges, and assemble the cast. Add small backpack-style snap-together straps so that when the arm is lain flat on a table, they will meet on top. The structure does snap together without these, but they will provide a lot more structural support and stop the cast from falling open should something strike the arm.

For the hinge idea to work, the hinge or hinges all have to be in a straight line. The contours of some limbs (for example, forearm and hand) would mean that the hinges couldn't all line up with each other, making it impossible. In this case, I would use snap-together contact plates on both sides, or join the halves using printable flexible material, depending on the application. The straps should have fixtures on both halves, so they can't get lost in the event contact plates are used on both halves instead of a hinge and a contact plate.

The cast is opened and laid down so that the two halves are both sitting on the table with the hinges between them, in the center. The patient lays his or her hand in the bottom half of the cast. The top half is then carefully closed over the bottom until the contact plates snap together. After that, the backpack straps are tightened.

Make two or three casts, not one. Your patient will want to be able to wash one of them while still wearing another, and it's nice to have a spare on hand in case one of them breaks. There are no metal connectors, just plastic and the backpack straps. This makes it easy to clean. Fill a dishwashing tub with hot soapy water (laundry detergent, not dish soap), swish it around for a few minutes, then rinse thoroughly with hot water from a spray nozzle - while wearing the other cast that you had printed for this exact purpose. Pat dry and put it in front of a fan for five minutes, or let it dry overnight.

[626Pilot]

Just wear it all the time so you do not brake the bones in the first place...

Ok, so how do i print artificial joints? Anyone know how i can transform MRI images to stl?

That's easy, the MRI comes with a $100,000/year support contract. That contract entitles you to pay a paltry $50,000 to have the aerospace/medical juggernaut who made the machine write an exporter.

It would be great to develop some printable body armor for athletes, motorcyclists, and clumsy people.