Threading a needle is hard, but at least you can see it. Think about how challenging it must be to thread a screw through a rod inside a bone in someone’s leg. Rice University seniors at the Brown School of Engineering set out to help doctors simplify the process of repairing fractured long bones in an arm or leg by inventing a mechanism that uses magnets to set things right.
Doctors simplify the process
The students who call themselves Drill Team Six chose the project pitched by Rice alumnus Dr. Ashvin Dewan, an orthopedic surgeon at Houston Methodist Hospital, to simplify a procedure by which titanium rods are placed inside broken bones to make them functional once more. For its efforts; the team won the top prize; the Excellence in Engineering Award; at the school’s annual Engineering Design Showcase.
The student team bioengineering majors Babs Ogunbanwo, Takanori Iida; Byung-UK Kang and Hannah Jackson and mechanical engineering majors Will Yarinsky and Ian Frankel learned from Dewan that surgeons require many X-rays to locate pre-drilled 5 millimeter holes in the rod. The holes allow them to secure the rod to the bone fragments and hold them together.
Bone fragments
The surgery typically requires doctors to insert the long rod with a guide wire inside into the end of the bone; drilling through marrow to align the fractured fragments. With that done; they depend on X-rays, their experience and, if necessary; a bit of trial and error to drill long surgical screws through one side of the bone; thread it through the rod and secure it to the other side.
“We want to reduce the amount of X-rays; the surgeon’s time, the operating room time; the setup time, everything,” Yarinsky said. The Rice team would make the wire adjacent to the holes magnetic; because neither skin nor bone hinder a magnetic field. “That way; the magnets hold their position and we can do the location process,” Frankel said. “Once we’ve found them and secured the rod; we remove the wire and the magnets with it.
3-D-printed carbon-fiber
“The exterior mechanism is a brace that can be securely attach to the arm or leg with Velcro. A mounted sensor can then be move along the stiff; 3-D-print carbon-fiber rods or around the limb until it locates the magnet. Then, the angle of the sensor can be adjusted. As each of the three degrees of freedom come into alignment with the target; a “virtual LED” lights up on a graphic display wired to the sensor. Then, the sensor is removed and a drill keyed to the mechanism inserted.