The removal of tissues from the human body is a fundamental aspect of surgical interventions, especially in Minimally Invasive Surgery (MIS). In MIS, one or multiple small incisions (approximately 3 to 10 mm) are made, and the body is accessed by long slender devices. MIS offers benefits such as less postoperative pain, and shorter hospital stays, driving a trend toward miniaturisation: smaller medical instruments. Current suction-based instruments are limited in performance by clogging, shaft miniaturisation challenges, and dependency on tissue composition. To address these limitations, alternative mechanisms for transportation have arisen such as friction-based transportation. This study presents the design and experimental validation of a flexible friction-based tissue transporting device for MIS. The device is designed to achieve transportation efficiency independent of tissue elasticity within a Young's modulus range of 1-110 kPa, utilising a cylindrical conveyor mechanism with wires to transport tissue. Experimental validation demonstrated consistent transportation efficiency (75%) across various tissue types, shapes, and orientations, though shaft curvature significantly affected performance and total reliability (81%). The device addresses some of the limitations of suction-based instruments, including reduced clogging, enhanced potential for miniaturisation, and transportation efficiency independent of tissue elasticity. While further improvements to the device design are necessary, it has the potential to improve MIS tissue removal procedures and patient outcomes.

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.

In many countries, Vacuum-Assisted Delivery (VAD) is the most common technique for instrumental vaginal delivery. Current VAD devices require the formation of a typical chignon on the infant’s scalp to achieve the necessary traction forces. This chignon, a swelling on the infant’s scalp, can lead to complications and, in severe cases, even death. This study addresses the question of how a new design for a VAD suction cup can reduce chignon formation while maintaining excellent adhesive performance. Three 3D-printed flexible suction cup designs with varying flexible lattice structures were designed to minimize chignon formation, and a bellow-shaped sealing lip was used to enhance the sealing performance. The performance of the novel designs are tested on an infant head surrogate and compared to a replica of the current commonly used Kiwi OmniCup®. Results indicated a significant reduction in scalp deformation, with the chignon volume ranging from 6.2% to 15.5% of that observed with the Kiwi replica. While the proposed suction cup designs show promise in reducing neonatal injuries by reducing the chignon formation, future work should focus on achieving a larger maximum traction force.

Suction grippers have the advantage to handle many different types and sizes of items, without being restricted by the dimensions of clamps to enclose an object and to handle objects more delicately.
However, the challenge of attaching these grippers to irregularly-shaped and rough surfaces remains a persistent issue. Despite advancements in research, the possibilities for miniaturisation, specific control, speed, and universal gripping capabilities still pose significant challenges. This study aims to overcome these obstacles by embedding magnetic intelligence within the material of a suction gripper and enabling the actuation of the attachment by an external magnetic field.
In this study, magnetic responsive soft materials are explored and different suction mechanisms are designed and validated to explore the opportunities of a magnetically actuated suction gripper. The miniaturisation options of the gripper are improved by implementing a compliant deploying mechanism. This results in the design of a magnetic actuated deployable suction gripper, using a thin magnetic membrane consisting of carbonyl iron particles in a silicone matrix material, in a frame of superelastic nitinol providing pressure on the rim and allowing for deploying.
A proof-of-principle prototype has been experimentally validated for attachment performance on a variety of curved surfaces in both dry and wet environments.
The attachment was achieved on curved surfaces with a radius of 50mm and 75mm, with a maximum attachment force of 2.89 \textpm 0.54 N. Observation suggests that only on surfaces with a curvature that is positioned exactly at the rim of the gripper attachment is not possible. For these surfaces, the nitinol wire rim prevented the flexible footprint membrane to seal onto the surface and leakage occurred.
The current gripper design is able to achieve a 75\% folding percentage, which allows it to enter hard-to-reach places in a small configuration while remaining enough surface area for attachment forces.
The proposed prototype serves as a foundation for further research in the development of reliable and effective magnetic-actuated suction grippers in a variety of configurations.

The surgical procedure of tissue extraction from the human body for precautionary or curative measures is common in many medical fields. Currently, aspiration catheters are the golden standard, enabling removal by means of a suction force. By Sakes et al., an alternative mechanism is proposed, transporting tissue based on friction, inspired by the egg-laying structure of wasps. Challenges within these devices comprise clogging and damage prevention, achieving adequate
transportation rates, transportation of tissue with differing elasticity properties and satisfying the dimensional restrictions of Minimally Invasive Surgery (MIS). Due to the vital impact of MIS, a tissue extraction device overcoming the previously mentioned barriers is highly desirable. The goal of this research is stated as follows, ‘design of a continuous tissue transportation mechanism compatible for MIS in which the transportation velocity is independent of tissue elasticity within the young’s modulus range of 1-110 kPa’. The stated elasticity span resembles a large range of tissue that can be encountered during MIS, whilst aspiration catheters are assumed to be suitable for the removal of liquids. Tissue extraction and retrieval are not included within the scope.

To achieve the stated objective, novel ideas are generated from both a dynamic and nature-based perspective and assessed by means of rapid prototyping. Within the final prototype, a cylindrical conveyor belt is created, consisting of a thread wrapped along a tubular body. Due to friction between the thread and tissue, the latter is transported whenever continuously rotating the thread in the direction of removal. Experiments are performed with the proof of principle prototype to investigate the effects of different rotational velocities, instrument orientation, and tissue shape on the transportation velocity of tissue and the corresponding efficiency and reliability. Maximum mean mass transportation rates of 7.75∓0.48, 8.43∓1.50, and 8.90∓0.56 g/min are attained, as a result of transporting tissue phantoms with a young’s modulus of approximately 1-10, 55, and 100-110 kPa respectively. Whether statistically, variance in transportation rates between these categories appears is not determined, as equivalent power supply voltages did not result in identical rotational velocities due to varying thread tension. However, as the transportation velocities match rates of clinically available morcellator and perfect reliability is attained, the potency of the designed mechanism as an alternative for aspiration-based instruments is demonstrated.