A novel microwave tool for robotic liver resection in minimally invasive surgery.

INTRODUCTION: During the last two decades, many surgical procedures have evolved from open surgery to minimally invasive surgery (MIS). This limited invasiveness has motivated the development of robotic assistance platforms to obtain better surgical outcomes. Nowadays, the da Vinci robot is a commercial tele-robotic platform widely used for different surgical applications. MATERIAL AND METHODS: In this work, the da Vinci Research Kit (dVRK), namely the research version of the da Vinci, is used to manipulate a novel microwave device in a teleoperation scenario. The dVRK provides an open source platform, so that the novel microwave tool, dedicated to prevention bleeding during hepatic resection surgery, is mechanically integrated on the slave side, while the software interface is adapted in order to correctly control tool pose. Tool integration is validated through in-vitro and ex-vivo tests performed by expert surgeons, meanwhile the coagulative efficacy of the developed tool in a perfused liver model was proved in in-vivo tests. RESULTS AND CONCLUSIONS: An innovative microwave tool for liver robotic resection has been realized and integrated into a surgical robot. The tool can be easily operated through the dVRK without limiting the intuitive and friendly use, and thus easily reaching the hemostasis of vessels.

A new microwave applicator for laparoscopic and robotic liver resection.

PURPOSE: Bleeding from parenchyma transection during a robotic hepatic surgery remains the most critical point affecting postoperative recovery and long-term survival. Various robotic devices with different types of energies have been proposed; however, each of these lack in steerability, efficacy, or accuracy. The aim of this work is to evaluate the feasibility and performance of a new steerable microwave resection device intended for minimizing intraoperative blood loss during laparoscopic and robotic liver resections. METHODS: The new device operating at 2.45 GHz was designed to accommodate the engineering constraints derived from its use for robotic surgery or laparoscopy, in which a steerable head is required and the internal cooling of forced gas or water is undesirable. The device design, analysis, and optimization were addressed using the most advanced commercial electromagnetic and thermal solvers to achieve the best results. To experimentally validate the results of the numerical analysis, many ablations were performed on a freshly explanted bovine liver by using a single device prototype with three levels of energy supplied to the tissue. During the ablation procedures, the time, temperature, and shape of the thermal lesion were recorded using thermocouples and an infra-red thermos camera. SUMMARY: Ex vivo tests showed good agreement with the numerical simulations, demonstrating the validity of the simplifications adopted to deal with the complex phenomena involved in the extreme hyperthermia of a living tissue. The high performance, thermal reliability, and robustness of the developed device were also demonstrated along with the possibility of reducing operation time and blood loss.

Soft Robotic Manipulator for Improving Dexterity in Minimally Invasive Surgery.

BACKGROUND: Combining the strengths of surgical robotics and minimally invasive surgery (MIS) holds the potential to revolutionize surgical interventions. The MIS advantages for the patients are obvious, but the use of instrumentation suitable for MIS often translates in limiting the surgeon capabilities (eg, reduction of dexterity and maneuverability and demanding navigation around organs). To overcome these shortcomings, the application of soft robotics technologies and approaches can be beneficial. The use of devices based on soft materials is already demonstrating several advantages in all the exploitation areas where dexterity and safe interaction are needed. In this article, the authors demonstrate that soft robotics can be synergistically used with traditional rigid tools to improve the robotic system capabilities and without affecting the usability of the robotic platform. MATERIALS AND METHODS: A bioinspired soft manipulator equipped with a miniaturized camera has been integrated with the Endoscopic Camera Manipulator arm of the da Vinci Research Kit both from hardware and software viewpoints. Usability of the integrated system has been evaluated with nonexpert users through a standard protocol to highlight difficulties in controlling the soft manipulator. RESULTS AND CONCLUSION: This is the first time that an endoscopic tool based on soft materials has been integrated into a surgical robot. The soft endoscopic camera can be easily operated through the da Vinci Research Kit master console, thus increasing the workspace and the dexterity, and without limiting intuitive and friendly use.

Total mesorectal excision using a soft and flexible robotic arm: a feasibility study in cadaver models.

BACKGROUND: Sponsored by the European Commission, the FP7 STIFF-FLOP project aimed at developing a STIFFness controllable Flexible and Learn-able manipulator for surgical operations, in order to overcome the current limitations of rigid-link robotic technology. Herein, we describe the first cadaveric series of total mesorectal excision (TME) using a soft and flexible robotic arm for optic vision in a cadaver model. METHODS: TME assisted by the STIFF-FLOP robotic optics was successfully performed in two embalmed male human cadavers. The soft and flexible optic prototype consisted of two modules, each measuring 60 mm in length and 14.3 mm in maximum outer diameter. The robot was attached to a rigid shaft connected to an anthropomorphic manipulator robot arm with six degrees of freedom. The controller device was equipped with two joysticks. The cadavers (BMI 25 and 28 kg/m2) were prepared according to the Thiel embalming method. The procedure was performed using three standard laparoscopic instruments for traction and dissection, with the aid of a 30° rigid optics in the rear for documentation. RESULTS: Following mobilization of the left colonic flexure and division of the inferior mesenteric vessels, TME was completed down to the pelvic floor. The STIFF-FLOP robotic optic arm seemed to acquire superior angles of vision of the surgical field in the pelvis, resulting in an intact mesorectum in both cases. Completion times of the procedures were 165 and 145 min, respectively. No intraoperative complications occurred. No technical failures were registered. CONCLUSIONS: The STIFF-FLOP soft and flexible robotic optic arm proved effective in assisting a laparoscopic TME in human cadavers, with a superior field of vision compared to the standard laparoscopic vision, especially low in the pelvis. The introduction of soft and flexible robotic devices may aid in overcoming the technical challenges of difficult laparoscopic procedures based on standard rigid instruments.

A novel magnetic-driven tissue retraction device for minimally invasive surgery.

INTRODUCTION: The purpose of this work is to design and validate an innovative magnetic-based device for tissue retraction for minimally invasive surgery. MATERIAL AND METHODS: 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. RESULTS: 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. CONCLUSION: The proposed retraction system resulted to be intuitive, reliable, robust and easy to use, representing a suitable device for MIS procedures.

Fiber Jamming Transition as a Stiffening Mechanism for Soft Robotics.

Robots 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 Soft Retraction System for Surgery Based on Ferromagnetic Materials and Granular Jamming.

In recent years, minimally invasive surgery (MIS) has gained wider acceptance among surgeons. MIS requires high skills for the operators, mainly due to its intrinsic technical limitations. Tissue manipulation and retraction remain the most challenging tasks; more specifically liver, stomach, and intestine are the organs mostly involved in retraction tasks for abdominal procedures. The literature reports an increasing interest toward dedicated solutions for abdominal tissue retraction tasks. To overcome the limitations of commercial systems and research prototypes, the aim of this study is the design, the realization, and the validation of a retraction system that is simple, reliable, easy to use, safe, and broadly compatible with MIS. The proposed retractor has two main components: (1) a soft central part with variable stiffness obtained by exploiting the granular jamming phenomenon for assuring, at the same time, safe introduction into the abdominal cavity and stable retraction and (2) two iron cylinders located at the two extremities of the device for anchoring the retractor to the abdominal wall by using the magnetic attraction force between these components and two external permanent magnets. System design has been performed by deeply investigating granular jamming principle and ferromagnetic properties of iron elements. Ex vivo and in vivo assessment has been carried out with the final aim to identify the most appropriate design of each retractor component and to demonstrate the advantages of using a soft system with variable stiffness during a retraction task.

Toward a Variable Stiffness Surgical Manipulator Based on Fiber Jamming Transition.

Soft robots have proved to represent a new frontier for the development of intelligent machines able to show new capabilities that can complement those currently performed by robots based on rigid materials. One of the main application areas where this shift is promising an impact is minimally invasive surgery. In previous works, the STFF-FLOP soft manipulator has been introduced as a new concept of using soft materials to develop endoscopic tools. In this paper, we present a novel kind of stiffening system based on fiber jamming transition that can be embedded in the manipulator to widen its applicability by increasing its stability and with the possibility to produce and transmit higher forces. The STIFF-FLOP original module has been re-designed in two new versions to incorporate the variable stiffness mechanism. The two designs have been evaluated in terms of dexterity and variable stiffness capability and, despite a general optimization rule did not clearly emerge, the study confirmed that fiber jamming transition can be considered an effective technological approach for obtaining variable stiffness in slender soft structures.

Devices for Measuring Cervical Dilation During Labor: Systematic Review and Meta-analysis.

IMPORTANCE: Measurement of cervical dilation is one of the major indicators of labor progression. At present, the criterion standard for this evaluation is digital examination, which results are sometimes inaccurate and extremely dependent on the subject (ie, obstetrician or midwife) experience. OBJECTIVE: In this systematic and meta-analysis review, the authors have gathered the vast majority of the instruments used for measuring cervical dilation and their clinical application; main features, potentialities, and the most significant constraints are underlined for each device. EVIDENCE ACQUISITION: Three of the most popular databases (ie, Web of Science, PubMed, and ClinicalTrials.gov) were used to identify all available cervimeters, by using single or combinations of the following keywords: "cervical," "dilation or dilatation," "cervimetry," "cervix," "uterine," "measurement," "labour or labor," "birth," and "monitoring." Only articles describing the design or a specific clinical application of an instrument for cervical dilation measurement during labor were selected. RESULTS: Twenty-five articles were deeply investigated by classifying them in 4 different homogenous groups on the basis of the method proposed for measuring cervical dilation. Suitable devices have not been realized yet, and this is the reason why nowadays the gynecologist/obstetrician still evaluates labor progression by digital examination. CONCLUSIONS AND RELEVANCE: Based on a critical analysis of the selected devices, ultrasound seems to be the most promising technology for future cervimetry realization; ultrasound is accurate in distance measurement, and the behind technology can be miniaturized. However, additional studies are necessary for optimizing the technology and developing an optimal solution.

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.