A study on the dexterity of surgical robotic tools in a highly immersive virtual environment: assessing usability and efficacy

Robot-assisted minimally invasive surgery (RAMIS) has produced noticeable benefits for patients in the recent years [1], making it a favorable approach for a wide range of surgeries. The benefits of improving the dexterity of patient side manipulators to enable surgeons to perform more complex tasks are offset by the increased complexity of teleoperation and cognitive and physical effort on the operator side typically. A right balance between higher dexterity and intuitive control in teleoperation is yet to be defined. In this study, a dexterous, anthropomorphic primary master controller was deployed to assess and compare the efficiency of simulated anthropomorphic surgical instruments in an immersive surgical concept. Virtual surgical training tasks were built using a gaming software engine (Unity) and performed using simulated surgical tools with extended degrees of freedom (DoF) in the surgical shaft and gripper and compared with the standard da Vinci (DV) grasper. The motion of the tools were controlled using commercial inertial measurement unit (IMU) sensor-based devices attached to the user's arms and hands. This article summarizes results obtained from three studies with similar features but different levels of complexity, taken with both lay users with no experience in surgery or teleoperation and surgeons experienced in RAMIS. The results showed that more than 70% of users achieved better results using articulated tools but required more physical and mental effort for teleoperation

Highly dexterous 2-module soft robot for intra-organ navigation in minimally invasive surgery

Background: For some surgical interventions, like the Total Mesorectal Excision (TME), traditional laparoscopes lack the flexibility to safely maneuver and reach difficult surgical targets. This paper answers this need through designing, fabricating and modelling a highly dexterous 2-module soft robot for minimally invasive surgery (MIS). / Methods: A soft robotic approach is proposed that uses flexible fluidic actuators (FFAs) allowing highly dexterous and inherently safe navigation. Dexterity is provided by an optimized design of fluid chambers within the robot modules. Safe physical interaction is ensured by fabricating the entire structure by soft and compliant elastomers, resulting in a squeezable 2-module robot. An inner free lumen/chamber along the central axis serves as a guide of flexible endoscopic tools. A constant curvature based inverse kinematics model is also proposed, providing insight into the robot capabilities. / Results: Experimental tests in a surgical scenario using a cadaver model are reported, demonstrating the robot advantages over standard systems in a realistic MIS environment. / Conclusion: Simulations and experiments show the efficacy of the proposed soft robot

Robotic technology and endoluminal surgery in digestive surgery

BACKGROUND. Colorectal cancer (CRC) is the third most common cancer in males and second in females, and the fourth most common cause of cancer death worldwide. The implementation of screening programs has allowed to the identification of an increasing number of early-stage neoplastic lesions. Presently, superficial colorectal neoplasms (including precancerous lesions and early cancer) can be resected in the colon by Endoscopic Mucosal Resection (EMR) and Endoscopic Submucosal Dissection (ESD), while in the rectum by Transanal Endoscopic Microsurgery (TEM). They are the preferred choices inside of the minimally invasive panorama regarding the CRC treatment. TEM technique offers more advantages than EMR and ESD, but it can’t overcome the recto-sigmoid junction. Many authors, research institutes and biomedical industries have proposed different solutions for microsurgery dissection of early lesions in the colon, but all these proposals have in common the development of platforms expressly designed for this use, with significant purchasing and management costs. The aim of our research project is to develop a robotic platform that allows to treat lesions throughout the colon limiting the costs of management and purchasing. This new robotic platform, developed in collaboration with Scuola Superiore Sant’Anna in Pisa, is called RED (Robot for Endoscopic Dissection). At the tip of a standard endoscope a hood (RED) is placed. RED is equipped by two extractable teleoperated robotic arms (i.e., diathermic hook and gripper); their motion is provided by onboard miniaturized commercial motors and a dedicated external platform. The endoscopist holds the endoscope near the lesion, while the operator drives the robotic arms through a remote control. MATERIALS AND METHODS. Several preliminary studies have been conducted in the following order. A first test was conducted for identification of force value for lifting and pulling maneuvers using a modified TEM instrument. A CAD study was conducted to determine the maximum size that the hood must have in order to overcome the critical angle represented by the splenic flexure. Several tests were conducted to determine the degrees of freedom of each robotic arm, starting with the CAD drawing to make subsequently the mock-ups of each configuration. Finally, a 3D mock-up was produced that was assembled on an endoscope to perform the in vitro test to evaluate the workspace and field of view using a pelvic trainer for TEM. RESULTS. The first test shown that the minimum force that the gripper will have to develop with the push-pull is 1.5N. The CAD study shown that the maximum dimensions the hood must have to overcome splenic flexure are: maximum diameter 28mm, maximum length 57mm. After several configurations was been tested, the final prototype features are: gripper arm with pitch sliding and open/close of the tip and diathermic hook arm with pitch, roll and sliding. There will be 6 such distributed motors: 3 external motors for the gripper arm that will operate through cables contained in a sheath adherent to colonscope and 3 embedded motors for diathermic hook arm (one integrated on the hood for the sliding degree of motion and the other two inside of the arm). The in-vitro test has been carried out to evaluate the workspace and they proved that the operating field vision is not obstructed by the hood and the working range is sufficiently wide to perform a dissection. CONCLUSION. Tests conducted up to this point have allowed us to identify the overall layout of the RED: dimensions, degrees of freedom, number and distribution of motors needed for the operation of robotic arms; moreover, it is proved that the device, once assembled, maintained the visual and operational field characteristics necessary to perform an accurate dissection. The next step will be to realize a RED steel final prototype and in-vivo tests will be carry out to replicate an endoscopic dissection into the colon

Smart Navigation in Surgical Robotics

La cirugía mínimamente invasiva, y concretamente la cirugía laparoscópica, ha supuesto un gran cambio en la forma de realizar intervenciones quirúrgicas en el abdomen. Actualmente, la cirugía laparoscópica ha evolucionado hacia otras técnicas aún menos invasivas, como es la cirugía de un solo puerto, en inglés Single Port Access Surgery. Esta técnica consiste en realizar una única incisión, por la que son introducidos los instrumentos y la cámara laparoscópica a través de un único trocar multipuerto. La principal ventaja de esta técnica es una reducción de la estancia hospitalaria por parte del paciente, y los resultados estéticos, ya que el trocar se suele introducir por el ombligo, quedando la cicatriz oculta en él. Sin embargo, el hecho de que los instrumentos estén introducidos a través del mismo trocar hace la intervención más complicada para el cirujano, que necesita unas habilidades específicas para este tipo de intervenciones. Esta tesis trata el problema de la navegación de instrumentos quirúrgicos mediante plataformas robóticas teleoperadas en cirugía de un solo puerto. En concreto, se propone un método de navegación que dispone de un centro de rotación remoto virtual, el cuál coincide con el punto de inserción de los instrumentos (punto de fulcro). Para estimar este punto se han empleado las fuerzas ejercidas por el abdomen en los instrumentos quirúrgicos, las cuales han sido medidas por sensores de esfuerzos colocados en la base de los instrumentos. Debido a que estos instrumentos también interaccionan con tejido blando dentro del abdomen, lo cual distorsionaría la estimación del punto de inserción, es necesario un método que permita detectar esta circunstancia. Para solucionar esto, se ha empleado un detector de interacción con tejido basado en modelos ocultos de Markov el cuál se ha entrenado para detectar cuatro gestos genéricos. Por otro lado, en esta tesis se plantea el uso de guiado háptico para mejorar la experiencia del cirujano cuando utiliza plataformas robóticas teleoperadas. En concreto, se propone la técnica de aprendizaje por demostración (Learning from Demonstration) para generar fuerzas que puedan guiar al cirujano durante la resolución de tareas específicas. El método de navegación propuesto se ha implantado en la plataforma quirúrgica CISOBOT, desarrollada por la Universidad de Málaga. Los resultados experimentales obtenidos validan tanto el método de navegación propuesto, como el detector de interacción con tejido blando. Por otro lado, se ha realizado un estudio preliminar del sistema de guiado háptico. En concreto, se ha empleado una tarea genérica, la inserción de una clavija, para realizar los experimentos necesarios que permitan demostrar que el método propuesto es válido para resolver esta tarea y otras similares

Phase Change Materials for Controllable Stiffness of Robotic Joints

Snake-like manipulators are well suited for operation in restricted and confined environments where the manipulator body can bend around obstacles to place an end effector at a difficult to access location. They require high stiffness when self-supporting weight against gravity and undertake precision manipulation task, but also require soft properties when operating in complex and delicate environments. A controllable stiffness manipulator has the potential to meet the application demands as it can switch between rigid and soft state. This thesis experimentally investigates the properties of four materials, (low melting point solder, hot-melt adhesive, low melting point alloy and granular material) as candidates for mechanically altering the stiffness of the joints/modules in snake-like manipulators. These materials were evaluated for bonding strength, repeatability, and activation time. Modules for a snake-like manipulator were fabricated using 3D printing and silicone casting techniques including, for the first time, variable stiffness joints that use hot-melt adhesive and low melting point alloy. These modules were evaluated for stiffness properties and low melting point solder based module was found to achieve a stiffness change 150X greater than the state of the art granular material approach. In addition, the proposed modules were able to support 25X of their own weight

Tissue manipulation using nano-particles ferrofluids for minimal access surgical applications

Nano-scale Iron-Oxide ferrofluids exhibit a special property, ‘superparamagnetism’, that induces an attractive force toward an external magnetic field. The aim of this project is to investigate the use of ferrofluids for tissue retraction during Minimally Access Surgery (MAS). In the in-vivo porcine experiments, 0.3 ml of ferrofluid (200 mg/ml concentration) containing 10 nm particles is injected subserosally into the small bowel, respectively. A 0.6 T magnetic field is created using a combination of 10 mm and 20 mm diameter Neodymium Iron Boron magnets. The vertical retraction distance is measured up to 80 mm and video-recorded. The results demonstrate the capacity of ferrofluid to facilitate the tissue manipulation and analysis of the migration of the particles within the tissue using micro computed tomography (CT). A theoretical model developed to validate the experimental results is also beneficial for predicting retraction force. In conclusion, this feasibility study provides a protocol for systematically using small volumes of ferrofluid, without the need to mechanically grasp the tissue

Cable-driven parallel mechanisms for minimally invasive robotic surgery

Minimally invasive surgery (MIS) has revolutionised surgery by providing faster recovery times, less post-operative complications, improved cosmesis and reduced pain for the patient. Surgical robotics are used to further decrease the invasiveness of procedures, by using yet smaller and fewer incisions or using natural orifices as entry point. However, many robotic systems still suffer from technical challenges such as sufficient instrument dexterity and payloads, leading to limited adoption in clinical practice. Cable-driven parallel mechanisms (CDPMs) have unique properties, which can be used to overcome existing challenges in surgical robotics. These beneficial properties include high end-effector payloads, efficient force transmission and a large configurable instrument workspace. However, the use of CDPMs in MIS is largely unexplored. This research presents the first structured exploration of CDPMs for MIS and demonstrates the potential of this type of mechanism through the development of multiple prototypes: the ESD CYCLOPS, CDAQS, SIMPLE, neuroCYCLOPS and microCYCLOPS. One key challenge for MIS is the access method used to introduce CDPMs into the body. Three different access methods are presented by the prototypes. By focusing on the minimally invasive access method in which CDPMs are introduced into the body, the thesis provides a framework, which can be used by researchers, engineers and clinicians to identify future opportunities of CDPMs in MIS. Additionally, through user studies and pre-clinical studies, these prototypes demonstrate that this type of mechanism has several key advantages for surgical applications in which haptic feedback, safe automation or a high payload are required. These advantages, combined with the different access methods, demonstrate that CDPMs can have a key role in the advancement of MIS technology.Open Acces