Thermal Modeling of Transient Heat Transfer in Tissue

We are looking at a high temperature welding technique for a potential alternative to sutures, staples, or cement for joining living tissue.  It turns out that temperatures in a certain range will denature proteins on both sides of the joint interface.  As the tissue cools the proteins entangle across the interface creating a strong bond without the introduction of any foreign material.  The interface temperature must be raised to an appropriate temperature for an appropriate duration without exceeding time and temperature limits that would result in tissue damage at the interface or in nearby tissue.  We undertook an initial scoping study using a SINDA-like thermal modeling package.  A one-dimensional transient model was created of the interface and surrounding tissue.  Approximate tissue physical characteristics and properties were included in the model.  Plausible heat deposition profiles were used as inputs for this initial scoping study. Figure 1 shows calculated spatial temperature distributions in the tissue at several times during a transient heating event.  Figure 2 shows the interface temperature as a function of time for one of the cases that was analyzed.  From the scoping study we determined that appropriate temperature and heat flow control were likely to be feasible and that further study is warranted.   We are currently developing a two-dimensional transient model in which we will include considerably more detail and accuracy in spatial and material properties and in the heat deposition profiles and make comparisons to experimental measurements.

Figure 1. Temperature Distributions

Figure 2. Transient Interface Temperature