Work

New sensor options for smart fracture implants and wearable devices: Laser-Doppler and white-light spectroscopy allow monitoring of bone regeneration via perfusion measurement

Year: 2025

Type: article

Abstract: The diagnostic options for monitoring fracture healing are currently limited to methods that expose patients to ionizing radiation, i.e. X-rays or computed tomography. The development of new methods that ideally allow continuous monitoring via smart implants or wearables is urgently needed. Laser-Doppler and white-light spectroscopy, non-invasive light-based methods, could allow to monitor fracture healing via changes in perfusion, but this has never been investigated. It was hypothesized that 1) blood flow (BF) increases before a linear increase in oxygen saturation (SO 2 ) and that 2) SO 2 in nonunion cases remains as low as the minimum in union cases. A longitudinal observational cohort study with tibial fracture patients was conducted with additional cross-sectional measurements in nonunion patients and healthy controls. To assess SO 2 , relative haemoglobin amount (rHb), and BF in the fracture gap, the ‘Oxygen to see’ (O2C) device was used. Thirty-five patients (20 longitudinal, 15 nonunion) and 28 controls were included. In the longitudinal group, SO 2 decreased, reaching a minimum (10 mm: 17.96 days, 16 mm: 15.50 days), and subsequently increased. BF increased to a maximum (10 mm: 12.90 days, 16 mm: 33.51 days), followed by a decrease. The SO 2 values in the nonunion group were similar to the minimum values in the longitudinal group. Findings in nonunion patients vs. controls differed only in SO 2 (10 mm: p < 0.001, 16 mm: p = 0.038), not in rHb or BF. Laser-Doppler and white-light spectroscopy provide characteristic SO 2 and BF trajectories that may serve to monitor fracture healing. • Smart implants could monitor fracture healing by measuring changes in perfusion. • The blood flow measured by laser Doppler rises to a maximum and then falls. • The SO 2 measured by white light spectroscopy drops to a minimum and then rises. • The SO 2 values in nonunion were similar to the minimum values in union.

Source: Biosensors and Bioelectronics

DOI: 10.1016/j.bios.2025.117442

Authors: Oana Scholz, Cedric Nowicki, Elke Warmerdam, Sandra Rother, Bergita Ganse

Institution: Saarland University

Language: English

Topic: Bone fractures and treatments

Subfield: Epidemiology

Field: Medicine

Domain: Health Sciences

SDG: Good health and well-being

Open Access status: hybrid

Estimated APC paid: $5,540