Tissue extraction in Minimally Invasive Surgery is often performed using a suction catheter, valued for its capability to continuously remove tissue from the body. However, suction catheters face limitations in further miniaturization and reliability due to energy losses and clogging. Kortman et al. (Kortman, 2023) proposed a solution: a soft tissue transporter that does not affect the surrounding tissue and enables miniaturization without sacrificing performance. The mechanism involves a soft silicone-based conveying toroid that transports tissue from one end of the tube to the other end of the tube. However, a shortcoming of the device is its inability to function as a continuous tissue transporter. Continuous transporters are often preferred as they shorten surgery times, reduce the amount of anesthesia needed and lower the overall operational costs compared to discrete transport mechanisms. Therefore, the goal of this study is to develop a continuous toroid tissue transporter, compatible with Minimal Invasive Surgery, for which the transport efficiency is independent of the tissue elasticity, shape and size. The final concept featured a toroid that was continuously everted while remaining stationary, enabling it to function as a conveyor-like mechanism. By integrating an internal skeleton with magnets at its edges, the toroid could be actuated externally using a gearbox. Additionally, an uniaxial mesh was incorporated into the toroid to allow flexibility in its width, allowing the shape grip to transport various objects, while preventing stretch in the length of the toroid, thereby improving eversion efficiency. A proof-of-principle prototype was developed to validate the working principle. Results demonstrated that the toroid efficiency was not limited by various tissue sizes, shapes or elasticities. Therefore, the study goal has predominantly been achieved.

Improvement of actuation efficiency can be achieved by further alignment between the actuation system and the toroid, as currently slip is causing a reduction in actuation efficiency. In conclusion, the Continuous Toroid Transporter demonstrates promise for surgical applications and other fields requiring precise object transportation and is recommended to be further developed.