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Students create automated bone-lengthening device

By

April 25, 2012

Rice University's Team Break-and-Make, with their automated linear distractor

Rice University's Team Break-and-Make, with their automated linear distractor

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Whether it's from injury, infection or malfunctioning genes, millions of children suffer from bone deformities at any given time. To help remedy the situation, doctors often resort to the painful practice of breaking the target bone and then repeatedly moving the ends apart as they attempt to grow together – a procedure known as distraction osteogenesis (DO), that has its share of risks and problems. Now, a team of undergrad students from Rice University (RU) in Texas has come up with a device they hope will make the lengthy process of bone-stretching both easier and safer for the young patients who have to endure it.

At the urging of Dr. Gloria Gogola, an orthopedic surgeon from nearby Shriners Hospital for Children in Houston, the RU team (mechanical engineering students Alvin Chou, Mario Gonzalez, Stephanie Herkes, Raquel Kahn and Elaine Wong) took on the daunting task of creating an automated linear distractor (eventually dubbed LinDi) that is both both self-adjusting and capable of monitoring and preventing potentially damaging stresses in adjacent soft tissues and nerves.

“The process of limb lengthening – essentially creating a localized mini-growth spurt – works well for bones, but is very hard on the soft tissues such as nerves and blood vessels,” Gogola said. “This team has done an outstanding job of designing a creative solution. Their device not only protects the soft tissues, it will ultimately speed up the entire process.”

With current DO rigs, long pins are embedded on both sides of the break in the bone to be lengthened. These are then attached to a bulky threaded frame outside of the appendage with a drive screw that must be regularly adjusted manually several times a day with a hex wrench. This pushes the pins further apart as the bone heals, but before it sets, allowing the gentle elongation of the bone over a period of several months. It's a burdensome task for patient and caregiver alike.

X-ray images of various distraction osteogenesis rigs in place

X-ray images of various distraction osteogenesis rigs in place

“The problem with the current device is that there’s a lot of room for error,” RU team member Kahn said. “You can imagine that one might forget to turn it once, or turn it the wrong way, or turn it too much. And a lot of problems can arise in the soft tissue and the nerves surrounding the bone," she added. "That’s the limiting factor of this process. But LinDi implements a motor to make the distraction process nearly continuous."

In fact, the battery-powered LinDi self-adjusts about 1,000 times a day, which allows it to better approximate bone growth. The team's innovative inclusion of a force-feedback sensor – a first for DO devices – monitors stress loads on surrounding tissues and shuts the system down if levels get too high, thus averting unnecessary trauma from the process.

Short-term animal testing with the help of Shriners hospital staff allowed the students to fine tune the device and confirmed that it works as planned – a nice feather in the bonnet of the soon-to-be grads and a welcome relief for the countless children and their parents who stand to benefit from this new technology in the years to come.

Source: Rice University

Check out the RU video below to learn more about LinDi.



About the Author
Randolph Jonsson A native San Franciscan, Randolph attended the U.S. Naval Academy at Annapolis, Maryland before finding his way to the film business. Eventually, he landed a job at George Lucas' Industrial Light + Magic, where he worked on many top-grossing films in both the camera and computer graphics departments. A proud member of MENSA, he's passionate about technology, optimal health, photography, marine biology, writing, world travel and the occasional, well-crafted gin and tonic!   All articles by Randolph Jonsson
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5 Comments

A friend of mine did this nearly 15 years ago while working for a company called Autogenisys they automated the Ilizarov apparatus. While they they didn't have a feed back system you didn't have to manually adjust it either.

Douglas Renfro
25th April, 2012 @ 09:40 pm PDT

what about the spinal column?

floccipaucinihilipilification
26th April, 2012 @ 03:41 am PDT

Looks like the entire device should be designed to wrap around the limb like a split tube for a more streamlined and esthetic look. It would also be less prone to snagging onto other things and allow use of clothes without alterations.

dgate
26th April, 2012 @ 05:44 am PDT

Sometime in the 50s orthodontists experimented with electrically stimulated braces to speed up the process. It worked far too well and placed enormous strain upon the nerves and blood vessels inside the canals in the upper & lower jaws. However this technique should work great at the face of the spreading bone. Very small electrical stimulation can draw osteoblasts to the joint face and encourage faster than normal bone growth. One major difference from the 50s is that now this can EASILY be digitally controlled to obtain best growth speed at the least risk to the patient. Additionally growth factors can be readily supplied directly in the desired growth region to lighten the strain on the osteoblasts.

StWils
26th April, 2012 @ 09:54 am PDT

Autogenesis still exists http://autogenesisinfo.com/automator.html Though you cant tell from that 90s style web page if they are still in the market. I'd bet they are still the patent holder though. I wrote the software in the original Autogenesis devices. (And have no connection whatsoever to the product or current owners.)

mclemens1969
26th April, 2012 @ 11:10 am PDT
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