Numerical Exploration of Lymphatic Biomechanics and Fluid Transport Optimization

The lymphatic system is essential for maintaining fluid balance, immune function, and waste clearance, yet its underlying biomechanical and fluid transport mechanisms remain understudied. This dissertation aims to investigate lymphatic pumping processes through numerical simulations and modeling.

First, the study combines the analysis of lymphatic valve behavior and single lymphangion flow dynamics to identify valve geometries and lymphangion lengths that maximize efficiency in facilitating unidirectional flow and overcoming pressure gradients.

Second, it examines the impact of phase shifts between consecutive lymphangions, determining the optimal phase differences for coordinated pumping in lymphatic vessel chains.

Building on these insights, an active pumping mechanism is investigated, coupling wall contraction intensity to the wall shear stress generated by fluid flow. This active pumping dynamically adjusts contraction amplitude and relaxation rates to adapt to varying flow conditions, emulating physiological responses.

Finally, the active pumping model is applied to simulate Lymphaticovenous Anastomosis (LVA), a surgical procedure to treat lymphedema. Simulations focus on interactions between lymphatic wall contractions and blood vessel pressure waveforms, exploring fluid mixing and drainage efficacy across different geometric configurations.

The findings of this research contribute to comprehensive understanding of lymphatic pumping mechanisms. These insights have the potential to advance therapeutic interventions for lymphatic disorders, improve the design of bioengineered lymphatic systems, and enhance outcomes of surgical procedures such as LVA.