Engineers from Rice University have developed a novel approach to fixing bone fractures that uses magnets to help fix the bones in place. The team of bioengineering students learned that the current procedure for fixing bone fractures requires many X-rays to locate pre-drilled 5mm holes in the rod which allow them to hold the bone fragments together.
Currently, a doctor inserts the long rod, that has pre-drilled holes in it into the patients bone. After this, using x-rays, experience and a touch of good luck the surgeon drills screws through the bone, through the rod, and out the other side holding everything in place.
Surgeons need luck
The downside of this technique is the reliance on numerous amounts of x-rays and possible extended surgery time. “We want to reduce the number of X-rays, the surgeon’s time, the operating room time, the setup time, everything,” Will Yarinsky, part of the ‘Drill team Six’ that conducted the research said.
Fellow team members include Babs Ogunbanwo, Takanori Iida, Byung-UK Kang, Hannah Jackson, and Ian Frankel. The team proposed making the wire adjacent the holes magnetic to help guide the screws into place.
“That way, the magnets hold their position and we can do the location process,” Frankel says. “Once we’ve found them and secured the rod, we remove the wire and the magnets with it.” The system also requires an external mechanism that attached to the fractured arm or leg with Velcro.
Sensor helps track perfect angle
A sensor can move along the rods or arm until it locates the magnet. The angle of the sensor is then adjusted to precisely understand the angle of the target. When all three degrees of freedom come into alignment with the target, a “virtual LED” lights up on a graphic display wired to the sensor.
The sensor is then removed and a drill keyed to the mechanism is inserted. “We do the angular part because the rod is not in the center of the leg, and the hole is not necessarily perpendicular to the surface,” Yarinsky notes. “The rod is about 10mm to 20mm thick and has a hole on one side and a hole on the other. We don’t want to hit the first hole at an angle where we miss the second and don’t go all the way through.”
FDA approval a possibility
The team have so far tested their device on mannequins with great results and will now pursue further research opportunities that could lead to getting Food and Drugs Administration approval so it can be used clinically.
“I’m very impressed with what the team put together,” says Rice alumnus Dr. Ashvin Dewan, an orthopedic surgeon at Houston Methodist Hospital, who earned a bioengineering degree at Rice in 2005.