Impedance spectroscopy to monitor fracture healing.

An estimated 7.9 million fracture injuries occur each year in the United States, of which a substantial fraction result in delayed or non-union. Current methods of monitoring fracture healing include taking x-rays and making clinical observations. However, x-ray confirmation of bone healing typically lags behind biologic healing, and physician assessment of healing is fraught with subjectivity. No standardized methods exist to assess the extent of healing that has taken place in a fracture. Without such knowledge, interventions to aid healing and prevent fracture non-union are often delayed, leading to increased morbidity and suffering to patients. We are developing an objective measurement tool that utilizes electrical impedance spectroscopy to distinguish between the various types of tissue present during the different stages of fracture healing. Preliminary measurements of cadaveric tissues reveal adequate spread in impedance measurements and differences in frequency response among different tissue types. Electrodes implanted in a simulated fracture created in an ex vivo cadaver model yield promising results for our system's ability to differentiate between the stages of fracture healing.