Computer-aided surgical simulation progressed significantly in the last decade. Careful planning is of great importance in order to limit the damage to healthy tissue during surgery. In particular, accurate modelling of the mechanical behaviour of the tissues is required. To achieve accurate prediction, biomechanical finite-element analysis (FEA) modelling of soft tissues is employed. Currently, many surgical procedures on human patients are not simulated yet can be relevant in minimally invasive surgeries to protect human health and to save human lives, particularly for surgeries with high accuracy requirements. Recent studies focused on colorectal cancer suggested that a 3D anatomical imaging segmentation could contribute in the definition of circumferential resection margin and in the pre-operative assessment of the pathological tumor regression grade, in this field literature is still scant. Although several researches have been introduced considering small displacements on the colorectal tissue, as a result of the forces exerted on adjacent tissues, FEA applied to colorectal surgical scenarios is still a challenge. To gain accurate models suitable for computer-aided surgical tools, many problems must be faced. In particular: a) free form surface modelling starting from MRI or CT scans; b) FEA pre-processing in terms of proper element selection and density (shell or solid according to the surgical district type and length characteristics) loads and boundary constraints definition; c) tissue constitutive material. In this research we aim to investigate these topics to enhance physical description of organs subjected to surgical operations. Therefore, this project has as goal provide a sensitivity analysis on three different geometric models, more in detail simulations will be performed using linear-elastic model and two hyperelastic models. The results will be valuated from multidisciplinary unit, bioengineering, engineering and surgeons involved in the research.
