Collaborative Research: Computational Modeling, Simulation, and Validation for Tissue Transplantation

Brown University, Providence RI

Investigators

Abstract

A fundamental problem in tissue transplantation in reconstructive surgery is how to determine the size of tissue flap that can be transferred without the development of necrosis. An autologous tissue flap is a unit of tissue that is transferred from one site to another of the same patient while maintaining its own blood supply. Improved understanding of the anatomy of tissue blood supply combined with advances in instrumentation and surgical techniques has resulted in modern methods to transfer tissue based on single arteries and veins. Surgeons still rely on personal experience to make a qualitative assessment of the adequacy of blood supply when deciding the size of the flap. If unsuccessful, the blood supply will be inadequate for the amount of tissue transferred, and portions of the flap will not survive, wasting the whole surgery. This can result in significant postoperative complications, additional surgery, increased morbidity, and increased medical costs. It is therefore important to develop a practical tool to enable the most reliable flap design based on the adequacy of blood supply. In order to address this problem, this research project will develop robust mathematical models that allow estimating the diameter of the perforating artery and the level of oxygenation in a tissue given its size and shape. The problem in hand is complicated and warrants a truly patient-specific approach. Modeling and simulations are necessary in multiple scales, i.e., at the perforator level, at the intermediate vascular network level, and at the capillary level. Validating the model with existing patient data is a challenge. The mismatch of the size of the blood vessel between the donor site and the recipient site creates additional problems. Based on these issues, the objective of this research is to create sophisticated computational tools for successful flap transfer. To achieve this goal, the specific research objectives are 1) to create a mathematical model to predict blood flow and oxygen supply in surgical flaps, 2) to generate data-driven simulation in vascular architecture and image-based validation in perforator flaps, and 3) to design the flap geometry based on (a) simulation results of blood flow and oxygen transport and (b) data clustering analysis of flap parameters from previous surgeries. The research project is a fundamental synergy of mathematical modeling, medical science, and surgery. The adopted interdisciplinary approach combines the expertise of the mathematical modeling community with that of radiologists and plastic surgeons.