Patient-specific models of human resected stomach after laparoscopic sleeve gastrectomy: experimental and computational results

The conspicuous increase in obesity rate occurring in the last decades in industrialized countries, often accompanied by high morbidity and high mortality rate, have been made obesity a global health concern. Bariatric Surgery is the most effective treatment for severe obesity. However, there are still many issues related to surgical procedures not yet been overcome. The importance of experimenting with a new rational approach based on bioengineering methods could strongly improve surgical approach by avoiding drawbacks and complications. The aim of this work is the construction of patient-specific computational models of the resected stomachs after laparoscopic sleeve gastrectomy able to interpret the structural mechanical behaviour of human gastric tissues. A coupled experimental- computational approach was performed. Experimental insufflation tests were performed on nine resected stomachs from LSG. Through a reverse engineering approach, nine specific- patient computational models were developed, aiming at simulating the experimental activities. A double-layered fiber-reinforced anisotropic hyperelastic material formulation was chosen. The experimental evidences provided the pressure-volume behavior of the resected stomachs. The comparison between experimental and computational results permitted to identify the set of the constitutive parameters. The stress-strain distribution described the region and the layer mainly solicited. An engineering approach allows us to characterize the mechanical behavior of the human gastric tissues. Reliable computational models will be used in understanding the biomechanics of the human stomach and will provide a clinical tool to help medical staff in optimizing bariatric procedures.