Patient-specific numerical simulation of compression therapy effects on interstitial fluid motion in lower limb lymphedema.

Lymphedema is a chronic condition characterized by impaired lymphatic drainage, leading to fluid accumulation, swelling, and progressive tissue remodeling. Compression therapy is the primary treatment used to alleviate swelling and enhance fluid drainage, yet its precise impact on interstitial fluid dynamics remains to be understood. In this study, we developed a poroelastic computational model that simulates fluid flow and tissue deformation in the lower limb under different compression strategies and compression levels. A key feature of our work is the integration of patient-specific geometries, allowing for a more physiologically accurate representation of tissue mechanics and fluid redistribution. We simulated edema formation induced by venous insufficiency by increasing blood capillary pressure from a baseline of 10-80 mmHg, and we observed that interstitial fluid pressure (IFP) increased from a baseline value of 0 mmHg to 8 mmHg, highlighting the impact of vascular dysfunction on fluid accumulation. Simulating complete blockage of lymphatic capillaries resulted in even higher IFP values (40 mmHg) compared to models with functional lymphatics, where IFP remained around 8 mmHg for high capillary pressures, underscoring the critical role of lymphatic drainage. We further showed that an increase in tissue permeability increases gravity-driven fluid pooling, potentially exacerbating swelling in lymphedematous limbs. Additionally, we incorporated an interface pressure derived from Laplace's law to offer a more realistic estimation of IFP and volume changes, emphasizing its importance for refining compression models and optimizing treatment strategies. These findings contribute to a deeper understanding of compression therapy's role in interstitial fluid drainage and provide a foundation for improving patient-specific lymphedema management.