Research SC
Aravis Biotech LLC
Technology aims at accurate measure of bone’s healing By Licia Jackson, Editor
www.scbizmag.com
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hen a person breaks a bone, it’s hurry up and wait. Most patients want to shed the cast and get back to their normal routine as soon as possible, but if they move too quickly, they risk reinjury. A new South Carolina company called Aravis Biotech LLC is developing technology that will provide a clear and simple way to see whether the bone has healed. It involves attaching a sensor to the plates and screws which surgeons use to hold a severely fractured bone together. The sensors are read using the same X-ray equipment health care providers use now. The partners in the project are two associate professors at Clemson University, Jeff Anker in chemistry and John DesJardins in bioengineering, and Caleb Behrend, an orthopedic surgeon at Virginia Tech. Right now, doctors recommend a standard number of weeks in a cast for patients with fractures, Behrend said. “For the lower leg, it’s up to 12 weeks out of work and heavy lifting.” The treating physician will prescribe an X-ray periodically, but it doesn’t give a complete picture of how the fracture is healing. DesJardins said using the historical standard means that doctors prolong treatment by an average of three weeks. “We’re trying to make a quantifiable and reliable way to measure healing so there will be more confidence on the part of the doctor,” DesJardins said. To accomplish this, a device is incorporated into the plate or the screws that are used to mend a fracture, Anker explained. On the X-ray, the amount of stiffness in the device can be measured. “You can see how much it is bending,”
Load Screw bending indicator mechanism Indicating dial moves within screw to measure bending load
Diagram/Aravis Biotech
Anker said. “It will bend less if the bone takes the load. The goal is to say yes or no, the bone is healing properly.” If the bone has healed sufficiently, the patient can begin walking on it. If not, the patient should stay off it and perhaps receive other therapy. Aravis, which is named for a mountain range in the French Alps where Anker’s family has a chalet, has received some funding for its research from several sources. A grant from SCRA will help take the project from academia to commercialization. One of the funded projects focuses on the dynamic hip screw, used to repair hip fractures. A simple pin added inside the hollow screw can be seen on an X-ray, with the range that it bends providing a good measure of healing. These screws are used to fix thousands of hip fractures, Anker said. In elderly patients, careful monitoring of healing is essential to avoid additional surgery and adverse impact on mortality. Another aspect of Aravis’s research fo-
X-ray of dynamic hip screw in fractured femur cuses on measuring infection in the area of a fracture. A device attached to an implant, plate or screw could react to changes in acidity, which can indicate infection. A gel in the device would swell with a change in acidity, causing a dial to react. The measurement on the dial could be read on an X-ray. The infecting agent can form a biofilm on the device that is highly resistant to antibiotics and the patient’s immune system, Anker said. If it is caught early, it can be treated; but if not, the device usually has to be removed to treat the infection and replaced once the infection is eradicated. That scenario would be costly to the patient in discomfort, time and money. For now, the Aravis researchers have been focusing on work with cadavers, boneequivalent models and computer simulations, Anker said. Later they will try to do a clinical study. “In a year we should have something more like a product,” Anker said. “We are trying to start raising more funds and growing as a company.”