Fajardo Jesús E, Carlevaro C Manuel, Vericat Fernando, Berjano Enrique, Irastorza Ramiro M
Instituto de Física de Líquidos y Sistemas Biológicos (CONICET), La Plata, Argentina.
Instituto de Física de Líquidos y Sistemas Biológicos (CONICET), La Plata, Argentina; Universidad Tecnológica Nacional, Facultad Regional Buenos Aires, Buenos Aires, Argentina.
J Therm Biol. 2018 Oct;77:131-136. doi: 10.1016/j.jtherbio.2018.08.009. Epub 2018 Aug 19.
The objective of this work is to quantify the relation between the value of the effective thermal conductivity of trabecular bone and its microstructure and marrow content. The thermal conductivity of twenty bovine trabecular bone samples was measured prior to and after defatting at 37, 47, and 57 °C. Computer models were built including the microstructure geometry and the gap between the tissue and measurement probe. The thermal conductivity (k) measured was 0.39 ± 0.06 W m K at 37 °C, with a temperature dependence of + 0.2%°C. Replacing marrow by phosphate-buffered saline (defatting) increased both the computer simulations and measurement results by 0.04 W m K. The computer simulations showed that k increases by 0.02-0.04 W m K when the model includes a gap filled by phosphate-buffered saline between the tissue and measurement probe. In the presence of microstructure and fatty red marrow, k varies by ± 0.01 W m K compared with the case considering matrix only, which suggests that there are no significant differences between cortical and trabecular bone in terms of k. The computer results showed that the presence of a gap filled by phosphate-buffered saline around the energy applicator changes maximum temperature by < 0.7 °C, while including the bone microstructure involved a variation of < 0.2 mm in the isotherm location. Future experimental studies on measuring the value of k involving the insertion of a probe into the bone through a drill hole should consider the bias found in the simulations. Thermal models based on a homogeneous geometry (i.e. ignoring the microstructure) could provide sufficient accuracy.
这项工作的目的是量化松质骨有效热导率值与其微观结构和骨髓含量之间的关系。在37、47和57°C下对20个牛松质骨样本脱脂前后的热导率进行了测量。建立了包含微观结构几何形状以及组织与测量探头之间间隙的计算机模型。在37°C下测得的热导率（k）为0.39±0.06W·m⁻¹·K⁻¹，温度依赖性为+0.2%/°C。用磷酸盐缓冲盐水替代骨髓（脱脂）使计算机模拟和测量结果均增加了0.04W·m⁻¹·K⁻¹。计算机模拟表明，当模型包括组织与测量探头之间由磷酸盐缓冲盐水填充的间隙时，k增加0.02 - 0.04W·m⁻¹·K⁻¹。在存在微观结构和脂肪性红骨髓的情况下，与仅考虑基质的情况相比，k的变化为±0.01W·m⁻¹·K⁻¹，这表明在热导率方面皮质骨和松质骨之间没有显著差异。计算机结果表明，能量施加器周围由磷酸盐缓冲盐水填充的间隙的存在使最高温度变化<0.7°C，而包括骨微观结构在内使等温线位置的变化<0.2mm。未来关于通过钻孔将探头插入骨中测量k值的实验研究应考虑模拟中发现的偏差。基于均匀几何形状（即忽略微观结构）的热模型可以提供足够的精度。
