Effect of the trabecular bone microstructure on measuring its thermal conductivity: A computer modeling-based study.

Area of Science:

• Biomedical Engineering
• Materials Science
• Orthopedics

Background:

• Trabecular bone's thermal properties are crucial for understanding heat transfer in bone tissue.
• Accurate quantification of thermal conductivity (k) is essential for developing effective thermal therapies and diagnostic tools.

Purpose of the Study:

• To quantify the relationship between trabecular bone's effective thermal conductivity and its microstructure and marrow content.
• To evaluate the influence of marrow content and microstructural details on thermal conductivity measurements and simulations.

Main Methods:

• Measured thermal conductivity of bovine trabecular bone samples at varying temperatures (37, 47, 57°C) before and after defatting.
• Developed computer models incorporating microstructure geometry and probe-tissue gaps.
• Compared experimental measurements with simulation results to assess the impact of marrow, microstructure, and gaps.

Main Results:

• Measured thermal conductivity (k) was 0.39 ± 0.06 W m⁻¹ K⁻¹ at 37°C, with a temperature dependence of +0.2%°C⁻¹.
• Defatting (replacing marrow with saline) increased k by 0.04 W m⁻¹ K⁻¹ in both measurements and simulations.
• Microstructure and marrow presence showed minimal variation (±0.01 W m⁻¹ K⁻¹) in k compared to matrix-only models, suggesting no significant difference between cortical and trabecular bone k.

Conclusions:

• Trabecular bone's effective thermal conductivity is largely independent of its intricate microstructure and marrow content.
• Thermal models can achieve sufficient accuracy even when ignoring microstructural details, simplifying future analyses.
• Experimental studies measuring bone thermal conductivity should account for potential biases introduced by probe insertion and surrounding gaps.