1,721,045 research outputs found
Anchoring frame for intra-abdominal surgery
No full textNatural orifice transluminal endoscopic surgery (NOTES) is one of the modern surgical techniques that led to the miniaturization of surgical tools and brings the concept of inserting many robotic units into the peritoneal cavity for executing “scarless” surgical tasks. However, the development of transabdominal anchoring systems that guarantee stability is recognized as a challenging issue in the design of miniature intra-abdominal robotic devices. A dedicated platform, exploiting magnetic coupling for anchoring, has been designed by respecting anatomical constraints, maximizing the volume to increase the number of embedded magnets, and consequently incrementing operating distance. The device is equipped with a SMA (shape memory alloy) mechanism that allows configuration change from an extended cylindrical (compliant for deployment) to a compact triangular (rigid for providing stability) design. The feasibility and the potential of the proposed platform have been demonstrated both in in vitro and in in vivo conditions on a human phantom and a porcine model, respectively
Design, Realization, and Assessment of a High-Fidelity Physical Simulator for the Investigation of Childbirth-Induced Pelvic Floor Damage
Full text linkVaginal delivery is one of the main causes of pelvic floor damage, which can lead to short- and long-term clinical consequences called pelvic floor dysfunctions. The number of women affected by this pathology is continuously rising, representing both a medical issue and an important financial burden. Prevention represents the best strategy of care, but it requires a deep understanding of the injury mechanisms, which is currently lacking. Simulation can help to identify the main factors affecting a clinical event, reducing the need for in vivo investigations. However, current simulators poorly mimic the pelvic structures and do not provide any feedback. These limitations led to the development of an innovative high-fidelity physical simulator to study the mechanisms behind pelvic floor damage caused by vaginal delivery. Anatomically correct gynecological structures were realized using soft materials able to resemble human tissue behavior. Ad hoc stretch sensors were realized with conductive fabric and integrated into the simulator to evaluate tissue elongation caused by the passage of the fetal head. Evaluation of the simulator was carried out both in laboratory conditions and by involving expert clinicians. Gynecologists determined that the simulator is a valid teaching and training tool that is able to provide feedback on instantaneous pelvic floor elongation, thus potentially preventing induced tissue damage
Fiber Jamming Transition as a Stiffening Mechanism for Soft Robotics
No full textRobots made of soft materials are demonstrating to be well suited in applications where dexterity and intrinsic safety are necessary. However, one of the most challenging goals of soft robotics remains the ability to change the stiffness of body parts to guarantee stability and to produce significant forces. Among soft actuation technologies reported in literature, the jamming phenomenon is now achieving resounding interest. The jamming transition was observed and studied both with granular and laminar material; however, there is a third possibility that is not gaining the attention that probably would deserve: the fiber jamming. The aim of this study was an attempt to analyze the main parameters influencing the fiber jamming transition as promising stiffening solution for soft robotics. A preliminary analysis to choose the most suitable filling material and the external membrane that compose the system was performed and three possible configurations were designed. The prototypes thus assembled were experimentally investigated by using two different setups: one for conducting comparative bending tests on the systems and another for assessing the mechanical properties of single filling fibers. The results of the tests are used to feature the correlation between the arrangement and the material properties of the fibers and the stiffening capability of the fiber jamming systems. The investigation has shown performances comparable with those obtained with granular and layer jamming, demonstrating that fiber jamming is a good candidate for integration in soft robotic devices
A novel magnetic-driven tissue retraction device for minimally invasive surgery
No full textThe purpose of this work is to design and validate an innovative magnetic-based device for tissue retraction for minimally invasive surgery. An intra-abdominal magnetic module is coupled with an extracorporeal system for establishing a stable attraction, and consequently a reliable tissue retraction. Once the retractor has been inserted into the abdomen, tissue retraction is not constrained by a fixed access port, thus guaranteeing a more flexible, safer and less invasive operation. The intra-abdominal unit is composed of an axial permanent magnet attached to a stainless-steel non-magnetic alligator clip by a traditional suturing thread. A miniaturized mechanism to adjust the length of the suturing thread for lengthening or shortening the distance between the tissue grasper and the internal magnetic unit is included. A multiphysics approach assured a dedicated design that thoroughly fulfills anatomical, physiological and engineering constraints. System functionalities were demonstrated both in in-vitro and ex-vivo conditions, reaching good results and promising outcomes in terms of effectiveness and maneuverability. The retractor was successfully tested in an animal model, carrying out a whole retraction procedure. The proposed retraction system resulted to be intuitive, reliable, robust and easy to use, representing a suitable device for MIS procedures
Preliminary experimental study on variable stiffness structures based on fiber jamming for soft robots
No full textSoft robotics opened a new set of technological challenges in using soft materials to build robots. The ability of change stiffness is among the most important, because it enables the possibility to tune forces exchanged with the environment. Granular and layer jamming transition have already demonstrated to be a promising approach for developing variable stiffness structures, but no studies have been dedicated to specifically fiber jamming so far. In this paper, we report a preliminary comparative study on fiber jamming applied to cylindrical structures. Fibers of different materials have been used as filler and tested under bending conditions. The results show that up to 380% of stiffness increase can be achieved, in line with data collected on similar devices that use granular jamming. The role of the main mechanical and geometrical parameters have been discussed: Elastic properties are fundamental, but optimal performance can be achieved only with ordered arrangements of the fibers; geometrical features seem secondary, but surface roughness has an important role in preventing sliding. This is a preliminary study, but it already defines a first set of guidelines that can help and promote future works on the development and integration of the fiber jamming in soft systems
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