Flexible endoscopes are still the gold standard in most natural orifice translumenal endoscopic surgery (NOTES) procedures; however their flexibility (necessary for navigating through the GI tract) limits their capabilities in terms of distal manipulation and stability. We propose a deployable endoscopic add-on aimed at locally counteracting forces applied at the tip of an endoscope. We analyze different designs: a fully soft version and two hybrid soft-folded versions. The hybrid designs exploit either an inextensible structure pressurized by a soft actuator or the stiffness provided by the unfolded “magic cube” origami structure. We focus on the fabrication and experimental characterization of the proposed structures and present some preliminary designs and integration strategies to mount them on top of current flexible endoscopes.

Numerous therapeutic transendoscopic procedures exist to treat lesions in the GI tract. However, these procedures are limited by their difficulty and the amount of training required to successfully perform them. The surgeon is tasked with simultaneously steering the distal tip of the endoscope, applying tension to tissue to retract it, and manipulating electro-cautery tools with limited dexterity. We propose a device designed to assist with anchoring and tissue retraction during endoscopic surgical procedures. The designed solution decouples the tissue-grasping function from the movement of the endoscope tip, leaving the surgeon free to use the endoscope tip solely for positioning of electro-cautery or biopsy tools deployed through the endoscope working channel. The anchoring and retraction device uses pop-up book MEMS techniques, allowing for a “flat” structure to expand into a 3-D structure. The proposed device has three main integrated components: a rigid expandable geometric structure, inflatable pneumatic actuators, and a vacuum gripper. These inflatable actuators include internal rigid discs, allowing for resistance to buckling while maintaining the benefits of the established lightweight, low profile actuator design scheme. Proof-of-concept ex vivo testing demonstrates that the integrated device can be used to retract tissue to a height of 13.5 mm, providing access for endoscopy tools to contact a sample of porcine stomach tissue.

Burgeoning transendoscopic procedures, such as endoscopic submucosal dissection (ESD), provide a promising means of treating early-stage gastric neoplasia in a minimally-invasive way. However, the remote locations of these lesions, coupled with their origination in the submucosal layers of the gastrointestinal tract, often lead to extreme technical, cognitive and ergonomic challenges which combat the widespread applicability and adoption of these techniques. Among these challenges is achieving the in vivo dexterity required to retract and dissect tissue. By leveraging workspace and force data obtained through clinical studies, we developed a modular, disposable, distally-mounted actuator (an `active endcap') that can augment an endoscopist's distal dexterity in ways that are not achievable with the endoscope's built-in degrees-of-freedom. The device consists of a flexible articulating `exoskeleton' manufactured via printed-circuit MEMS (PCMEMS) which engages and deflects electrosurgical tools that are passed through the endoscopic working channel. Embedded proprioceptive sensing is implemented on-board using distributed LED/phototransistor pairs and the principle of light intensity modulation (LIM). The distal degree-of-freedom is actuated using shape memory alloy (SMA) technology, and the actuation transmission system is fully contained within a 1-inch-long end cap that can be mounted on the distal end of the endoscope, thereby obviating the need for a mechanical connection to a proximal source. Proof-of-concept tests demonstrate that the actuator adds over 50 degrees of distal articulation to existing tools and can generate 450 mN of lateral force which has been clinically determined to be sufficient for performing circumferential incisions in ESD.

This paper introduces a manufacturing technique which enables the integration of soft materials and soft fluidic micro-actuators in the Pop-up book MEMS paradigm. Such a technique represents a promising approach to the design and fabrication of low cost and scalable articulated mechanisms provided with sensing capabilities and on-board actuation with potential applications in the field of minimally invasive surgery. Design and integration of soft components in the rigid-flex laminates is described along with the resulting soft pop-up mechanisms realized at different scales. Prototype characterization is presented, demonstrating forces and dexterity in a range suitable for surgical applications, as well as the possibility to integrate sensing capabilities. Based on these results, a multi-articulated robotic arm is fabricated and mounted on top of an endoscope model to provide a proof of concept of simple robotic mechanisms that could be useful in a surgical scenario.

This paper presents the concept design of a modular soft manipulator for minimally invasive surgery. Unlike traditional surgical manipulators based on metallic steerable needles, tendon-driven mechanisms, or articulated motorized links, we combine flexible fluidic actuators to obtain multidirectional bending and elongation with a variable stiffness mechanism based on granular jamming. The idea is to develop a manipulator based on a series of modules, each consisting of a silicone matrix with pneumatic chambers for 3-D motion, and one central channel for the integration of granular-jamming-based stiffening mechanism. A bellows-shaped braided structure is used to contain the lateral expansion of the flexible fluidic actuator and to increase its motion range. In this paper, the design and experimental characterization of a single module composed of such a manipulator is presented. Possible applications of the manipulator in the surgical field are discussed.

This paper presents a highly compact fibre-optic system based on light intensity modulation for multi-segment flex sensing in pliable robot arms, e.g., articulated surgical instruments. This fibre-optic arrangement is 7.5 mm in diameter and is comprised of a two-segment flexible and stretchable Steiner chain arm section with twelve housings at the distal side which accommodates passive cables. The displacement of each cable will be used to determine the bending. This Steiner chain section is followed by a basal rigid fibre-optic sensing unit integrated with a low-friction retractable distance modulation array which couples the motion of the passive cables with light-emitting optical fibres. The low-friction retractable distance modulation array uses steel spring-needle double sliders to reduce the hysteresis and to recover reference sensor values when the arm returns to its original straight configuration. The U-shape loopback design of the optical fibres allows integration of all electronics away from the sensing site. The experimental results indicate a maximum bending angle error of 6° in one individual segment of the two-segment arm with respect to reference angle values calculated from camera images.

This paper introduces an optical based three axis force sensor which can be integrated with the robot arm of the EU project STIFF-FLOP (STIFFness controllable Flexible and Learnable Manipulator for Surgical Operations) in order to measure applied external forces. The structure of the STIFF-FLOP arm is free of metal components and electric circuits and, hence, is inherently safe near patients during surgical operations. In addition, this feature makes the performance of this sensing system immune against strong magnetic fields inside magnetic resonance (MR) imaging scanners. The hollow structure of the sensor allows the implementation of distributed actuation and sensing along the body of the manipulator. In this paper, we describe the design and calibration procedure of the proposed three axis optics-based force sensor. The experimental results confirm the effectiveness of our optical sensing approach and its applicability to determine the force and momentum components during the physical interaction of the robot arm with its environment.

The class of Pneumatically-driven Lower-pressure Soft Actuators (PLSA) is a popular research topic as it can be potentially used in the surgical robotic applications. One fundamental problem lying in the PLSA research is the lack of a generally validated model for the complex nonlinear dynamic behaviours. In this paper, a new coefficient-adaptive orthonormal basis function model structure is specifically developed for the identification of the general PLSAs. It is a parameter-independent way directly used to identify the dynamic relation between the actuating pressures and the principal degrees of freedom of a PLSA, the bending and the steering. The approach is based on a modified auxiliary kinematic setting. Following the discussion of the identification procedure, the implementations for the double chamber bending and steering are demonstrated. The results show that the proposed approach can accurately capture the nonlinear pressure-shape dynamics. The approach is also efficient in the real-time applications. It can be further used to improve the current control design for the PLSAs in robotic applications.

As a result of the rapid spreading of stereoscopy in the consumer market, three-dimensional (3D) vision systems are replacing two-dimensional devices. A fast growing technology in the 3D visualization systems market is multi-views autostereoscopic displays (ADs). However, these devices have not yet found a direct application in minimally invasive surgery (MIS), as it is really challenging to embed a high number of point-of-views in a device which has to pass through a MIS incision. The aim of this work is the development of a miniaturized vision acquisition system for MIS, which can be interfaced with multi-views ADs. The system is anchored by a magnetic link to the abdomen and freely moved by magnetic actuation to adjust the point of view and the horizon of the cameras. The laparoscope can embed up to 9 cameras, while matching typical MIS access incision size.

This paper presents the concept design, the fabrication and the experimental characterization of a unit of a modular manipulator for minimal access surgery. Traditional surgical manipulators are usually based on metallic steerable needles, tendon driven mechanisms or articulated motorized links. In this work the main idea is to combine flexible fluidic actuators enabling omnidirectional bending and elongation capability and the granular jamming phenomenon to implement a selective stiffness changing. The proposed manipulator is based on a series of identical modules, each one consisting of a silicone tube with pneumatic chambers for allowing 3D motion and one central channel for the implementation of the granular jamming phenomenon for stiffening. The silicone is covered by a novel bellows-shaped braided structure maximizing the bending still limiting lateral expansion. In this paper one single module is tested in terms of bending range, elongation capability, generated forces and stiffness changing.

Magnetically driven wireless capsule endoscopy (WCE) represents one of the last achievements in the research of minimally invasive tools for gastrointestinal tract (GI) diagnosis. Recently, capsule localization methodologies have been employed to enable system autonomy maintaining a magnetic link with the device and managing interaction forces with GI tissues. To achieve these objectives, the locomotion platforms exploit automatic motion in some degrees of freedom and unsupervised contact with the external patient abdomen can occur. In this paper safety issues are faced; in particular a safety system, able to monitor pressure with patient abdomen, has been designed, characterized, and integrated with a magnetically driven WCE locomotion platform. New technologies, such as smart textiles, have been employed as sensible element. The proposed system showed promising results in controlling the pressure exerted on the abdomen respecting safety limits and increasing the efficiency and range of locomotion.

The novel concept of Trans-abdominal Active Magnetic Linkage for laparoendoscopic single site surgery has the potential to enable the deployment of a bimanual robotic platform trough a single laparoscopic incision. The main advantage of this approach consists in shifting the actuators outside the body of the patient, while transmitting a controlled robotic motion by magnetic field across the abdomen without the need for dedicated incisions. An actuation mechanism based on this approach can be comprised of multiple anchoring and actuation units, mixed depending upon the specific needs. A static model providing anchoring and actuation forces and torques available at the internal side of the magnetic link was developed to provide a tool to navigate among the many possibilities of such an open ended design approach. The model was assessed through bench top experiments, showing a maximum relative error of 4% on force predictions. An example of a single degree of freedom manipulator actuated with the proposed concept and compatible with a 12-mm access port is able to provide an anchoring force of 3.82 N and an actuation force of 2.95 N.