Fiber-Optic Bragg Grating Sensors for Biomechanical Analysis of Fracture Healing

• Published in: IEEE sensors journal Vol. 21; no. 21; pp. 24177 - 24184
• Main Authors: Kalinowski, Alessandra, Linessio, Rafael P., Mendonca, Celso J. A., Dreyer, Uilian J., Antunes, Paulo, Ramos, Antonio, Silva, Jean Carlos Cardozo da
• Format: Journal Article
• Language: English
• Published: New York IEEE 01-11-2021; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: <italic xmlns:ali="http://www.niso.org/schemas/ali/1.0/" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">in vivo tests; Biomechanical engineering; Biomechanics; Biomedical materials; Bone callus; Bones; Bragg gratings; circular external fixator; Dynamic tests; Femur; fiber Bragg gratings; Fiber gratings; Fiber optics; Fractures; Healing; In vivo methods and tests; Inspection; Optical sensors; Pins; Resonant frequencies; Sensors; Static tests; Stiffness; Strain; Temperature sensors
• ISSN: 1530-437X; 1558-1748
• DOI: 10.1109/JSEN.2021.3114981

Despite the complexity of bone callus formation, the evaluation of fracture healing is usually performed based on x-ray visual inspection, a subjective and imprecise method. The main objective of this study is to access the evolution of bone callus. Tests were performed using a synthetic femur and an in vivo subject (preliminary results). Fiber Bragg Grating (FBG) sensors were glued to the Schanz pins of a circular external fixator for the analysis of static and dynamic strain. Three materials of different densities were inserted in the fracture site (synthetic femur) to simulate the formation of bone callus. The results from the static tests with the synthetic femur show that the strain measured on the Schanz pins presented an expected deformation pattern, according to a previous simulation. It was possible to differentiate bone callus stiffness through strain detected in the Schanz pins. The results from the dynamic tests allowed to find the first resonant frequency of each bone callus, with a difference of 4 Hz between them, measured by the FBG sensor. In the preliminary in vivo tests, the FBG sensor results demonstrated its technical viability to detect the bone callus healing stage. Nonetheless, a comprehensive study using a higher number of subjects is necessary. Being a noninvasive technology, it has the potential to become an important tool to assist medical staff in bone healing analysis.