"The sensor provides opportunities to make specific and detailed diagnostics for a particular patient and to tailor care based on very objective and quantitative measures," said Eric H. Ledet, Ph.D., assistant professor, at Rensselaer Polytechnic Institute in Troy, N.Y. "This highly unique sensor is very small (4 mm diameter and 500 microns thick), is wireless, batteryless, and requires no telemetry within the body. Its simplicity makes it less prone to failure and very inexpensive to produce."
The orthopedic implant acts as a carrier for the sensor. The wireless sensor can monitor load, strain, motion, temperature, and pressure in the challenging in vivo environment. It can be placed into a spinal or fracture fixation implant, for example, to determine the patient's progress.
"For the patient that is progressing well, the information from the sensor enables the physician to determine that the patient can return to work without risk of injury," said Ledet. "The number of lost days at work is reduced."
It can also alert the physician to potential problems, indicating that additional interventions may be needed.
"By maintaining a simple platform, we're able to customize the sensor and make it very, very small so it can be incorporated into a lot of different implants," said Rebecca A. Wachs, MS, Rensselaer Polytechnic Institute. "By changing one small parameter, we can change the sensitivity of the sensor itself."
Ledet reported a number of major breakthroughs with the sensor technology in the last eighteen months. Although the researchers are manually producing the sensor, they anticipate it will eventually be mass produced—driving the price down further.