Robotic Grasper Research Articles

Modified pulley maneuver to guide surgical plane in minimally invasive liver resection.

Achieving an adequate surgical plane through optimal traction is crucial for liver parenchymal transection in minimally invasive liver surgery (MILS). MILS is more technically demanding than open liver surgery because of limited instrument mobility and the inability to use the surgeon's hand, potentially leading to iatrogenic injuries. The Pulley maneuver using barbed sutures has been used for laparoscopic hepatectomy; however, the sutures are single-use and may pass through the liver parenchyma, making it uneconomical and inflexible. To address this, we developed a modified pulley maneuver using a barbed with a nonabsorbable polymer clip and metal clip for parenchymal transection in MILS. Before liver transection, we prepared barbed sutures and attached nonabsorbable polymer and metal clips to the distal end. The metal clip prevented the nonabsorbable polymer clip from slipping, allowing one suture to be reused three times. Before liver transection, the suture was passed through the liver surface twice, with the clips to reduce iatrogenic damage. The sutures were anchored to the diaphragm or peritoneum for optimal liver traction. A laparoscopic or robotic grasper adjusted the suture tension for the appropriate transection plane. In open-pit-shaped resections, the liver is lifted ventrally for deeper access, whereas in wedge-shaped resections, it is elevated in the caudal view. The modified pulley maneuver provides stable liver traction. The modified pulley maneuver is an economical, simple, and feasible method for enabling stable liver traction, thereby enhancing the versatility and safety of liver parenchymal transection in MILS.

How Safe Are the Laparoscopic and Robotic Graspers? Evaluation of the Novel Avatera Robotic Surgical System: An Acute In Vivo Study on a Porcine Model.

To evaluate the tissue injury caused by the force applied by the roboticassisted graspers of avatera robotic surgical system on bowel tissue. An experimental in vivo porcine model with 1 pig was conducted. After a standard transperitoneal setup of the avatera robotic surgical system, different laparoscopic and robotic graspers were used on the bowel with maximum force applied each time. Robotic atraumatic grasper, laparoscopic right angle grasper, laparoscopic curved grasper, and laparoscopic atraumatic grasper were used. After using all graspers, the pig was sacrificed. The bowel segments were resected and sent for histological analysis. The pathologist reported that all the graspers caused signs of acute inflammation without any irreversible damage or signs compatible with ischemia of the tissue. No significant difference in histology was observed between the graspers. No permanent damage was caused by graspers, except for acute, reversible inflammation. Concluding, the avatera grasper could be safe to use on bowel segments, independent of the applied pressure.

Intraoperative Pancreatoscopy During Robotic Pancreatoduodenectomy and Robotic Distal Pancreatectomy for Intraductal Papillary Mucinous Neoplasm with Involvement of the Main Pancreatic Duct.

Intraductal papillary mucinous neoplasm (IPMN) with involvement of the main pancreatic duct usually requires surgical resection. Consensus is lacking whether to partially or completely resect the pancreatic portion with a dilated main pancreatic duct. Intraoperative pancreatoscopy may be useful to determine the extent of IPMN to tailor surgical resection and was recently studied in a large prospective international study. IPMN is increasingly utilized using a robotic approach. Studies describing the technical approach to intraoperative pancreatoscopy in robotic pancreatoduodenectomy and robotic distal pancreatectomy are lacking. During robotic pancreatoduodenectomy, pancreatoscopy is performed once the pancreas neck is transected. The scope is advanced via a laparoscopic port into the left and right-sided pancreatic duct, guided by robotic graspers. During robotic distal pancreatectomy, pancreatoscopy is performed before complete parenchymal transection. The scope is advanced through an anterior ductotomy to examine the duct and guide the pancreatic transection line. Tips and tricks how to perform the procedure efficiently without complications are detailed. In total, 28 robot-assisted pancreatoscopies were performed during robotic pancreatoduodenectomy and robotic distal pancreatectomy. No intraoperative complications resulting from the intraoperative pancreatoscopy were noted. In the 2 described procedures, the added time required to perform the pancreatoscopy was 6 and 17 minutes, respectively. Both patients recovered without complication and were discharged on postoperative day 5 for the robotic pancreatoduodenectomy and day 6 for the robotic distal pancreatectomy. Intraoperative pancreatoscopy can be safely performed during both robotic pancreatoduodenectomy and robotic distal pancreatectomy for IPMN with the involvement of the main pancreatic duct. An international prospective study has recently been completed with this technique.

Optimal Control of Dielectric Elastomer Actuated Multibody Dynamical Systems.

In this work, a simulation model for the optimal control of dielectric elastomer actuated flexible multibody dynamics systems is presented. The dielectric elastomer actuator (DEA) behaves like a flexible artificial muscle in soft robotics. It is modeled as an electromechanically coupled geometrically exact beam, where the electric charges serve as control variables. The DEA-beam is integrated as an actuator into multibody systems consisting of rigid and flexible components. The model also represents contact interaction via unilateral constraints between the beam actuator and, for example, a rigid body during the grasping process of a soft robot. With a mathematically concise and physically representative formulation, a reduced free energy function is developed for the electromechanically coupled beam. In the optimal control problem, an objective function is minimized while the electromechanically coupled dynamic balance equations for the multibody system have to be fulfilled together with the complementarity conditions for the contact and boundary conditions. The optimal control problem is solved via a direct transcription method, transforming it into a constrained nonlinear optimization problem. The electromechanically coupled geometrically exact beam is firstly semidiscretized with one-dimensional finite elements and then the multibody dynamics is temporally discretized with a variational integrator leading to the discrete Euler-Lagrange equations, which are further reduced with the null space projection. The discrete Euler-Lagrange equations and the boundary conditions serve as equality constraints, whereas the contact constraints are treated as inequality constraints in the optimization of the discretized objective. The constrained optimization problem is solved using the Interior Point Optimizer solver. The effectiveness of the developed model is demonstrated by three numerical examples, including a cantilever beam, a soft robotic worm, and a soft robotic grasper.

Dynamic analysis of a three-fingered deployable metamorphic robotic grasper

This paper selects a three-fingered deployable metamorphic robotic grasper as the studied object and presents a distributed dynamic modeling method for the multi-body system based on the metamorphic mechanism. Considering that the grasper contains two independent motion configurations, dynamic models of them are independently established, and then the final dynamic model of the whole grasper is formed. To further improve the modeling accuracy, it is creatively proposed that irregular links can be seen as rigid connections of multiple regular links, by which the dynamic model for the deployment motion of the grasper is firstly established via the Lagrange equation. For the grasping motion, since the finger of the grasper can be equivalent to a planar 4R serial mechanism, the dynamic models of the base mechanism and the basic module are established by the Lagrange equation to obtain the relationships between the driving forces and the equivalent torques. The whole grasper is then established by the recursive Newton-Euler method to enhance the modeling efficiency. Finally, the effectiveness of the dynamic model is well verified by the dynamic simulation.

A computational design of robotic grasper by intelligence-based topology optimization for microassembly and micromanipulation

In robotic microassembly and micromanipulation, robotic grasper plays a vital role in picking up and releasing the product. However, the design synthesis method for creating a new robotic grasper has not deeply considered yet. Therefore, this article presents an effective computation method for designing a new robotic grasper that can be used for microassembly and micromanipulation. Firstly, a new structural scheme of robotic grasper is made by using the topology procedure. The compliance is the objective with the stress constraint during the topology. Then, a new variant of the grasper is refined where compliant joints are needed to reach the better compliance and the elastic motions of grasping hands. In the second phase, the modeling establishment for predicting the behaviors of the grasper are built via using the intelligent computation, namely GENFIS#1-neuro-fuzzy inference system (ANFIS), GENFIS#2-ANFIS, and GENFIS#3-ANFIS. The numerical data of the grasper are collected via the design of experiment-based finite element method. The results indicated that the GENFIS#3-ANFIS type is the best solver for modeling the hand’s stroke, the resonant frequency, and the strain energy. Meanwhile, the GENFIS#2-ANFIS type was the best procedure for modeling the stress. Subsequently, the optimum geometrical dimensions of the grasper are searched by using the Bonobo optimizer to improve the four mentioned performances of the grasper. In the circumstance #1, the results found that the hand’s displacement is about 0.0922 mm, the resonant frequency is 67.6247 Hz, the elastic energy is 1.4550 mJ, and the stress is 6.7249 MPa. The circumstance #2 determined the resonant frequency of 67.6247 Hz, the hand’s displacement of 0.0883 mm, the elastic energy of 1.9914 mJ, and the stress of 6.7086 MPa. Finally, the circumstance #3 found the elastic energy of 2.0501 mJ, the hand’s displacement of 0.0884 mm, the resonant frequency of 80.0012 Hz, and the stress of 6.7046 MPa. Statistically compared with the other methods, the presented method is the simple and effective procedure for designing 3D printed robotic grasper.

V03-07 INTRACORPOREAL ROBOTIC PYELOLITHOTOMY USING THE BOSTON SCIENTIFIC SWISS LITHOCLASTⓇ TRILOGY LITHOTRIPTER

You have accessJournal of UrologyCME1 May 2022V03-07 INTRACORPOREAL ROBOTIC PYELOLITHOTOMY USING THE BOSTON SCIENTIFIC SWISS LITHOCLASTⓇ TRILOGY LITHOTRIPTER Micah Levy, Chih Peng Chin, Krishna T. Ravivarapu, Osama Al-Alao, and Michael Palese Micah LevyMicah Levy More articles by this author , Chih Peng ChinChih Peng Chin More articles by this author , Krishna T. RavivarapuKrishna T. Ravivarapu More articles by this author , Osama Al-AlaoOsama Al-Alao More articles by this author , and Michael PaleseMichael Palese More articles by this author View All Author Informationhttps://doi.org/10.1097/JU.0000000000002539.07AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookLinked InTwitterEmail Abstract INTRODUCTION AND OBJECTIVE: The Boston Scientific Swiss LithoClast© Trilogy Lithotripter was released in 2019, intended for use in percutaneous nephrolithotomy (PCNL). Its use has been shown to improve efficiency for stone fragmentation and removal, however, it has never been used for intracorporeal procedures. Our video depicts the first use of the Trilogy lithotripter in intracorporeal robotic pyelolithotomy and discusses the indications and advantages of this technique. METHODS: The patient was a 65-year-old female with a large left staghorn calculus with hydronephrosis and a left ureteropelvic junction (UPJ) obstruction. The combination of a staghorn stone with a UPJ obstruction indicated the use of robotic pyelolithotomy for stone removal and UPJ reconstruction. Due to the size and location of the stone, it was decided to use the Trilogy lithotripter for more efficient stone removal. The patient was consented to undergo a robotic pyelolithotomy with Trilogy lithotripsy. RESULTS: The patient was positioned in the flank position. The robot was docked, and the abdomen was insufflated. Initial dissection was made, and the colon was mobilized, revealing a hydronephrotic kidney with significant inflammation and a large staghorn stone branching into the upper, middle, and lower pole. The 2.4mm Trilogy probe was passed into the abdomen through the 12mm assistant's port and under direct vision the stone was segmented into several large fragments which were manually removed by the robotic graspers. Renal endoscopy was performed using a disposable LithoVue™ ureteroscope and remnant stones were removed using a stone basket until the kidney and ureter were noted to be stone free. The operation was completed successfully with minimal estimated blood loss and no intraoperative or postoperative complications. The patient returned for a six-week follow-up, and CT scans showed full stone clearance with no signs of hydronephrosis. CONCLUSIONS: This was the first documented use of the Trilogy lithotripter during intracorporeal surgery. The Trilogy’s efficacy in intracorporeal surgery is partially due to its built-in cooling system which allows for use of the Trilogy with reduced need for continuous irrigation which must be limited during robotic pyelolithotomy. Thus, this technique was indicated for complex procedures such as robotic pyelolithotomy for stone removal and concurrent UPJ reconstruction. It proved to be an efficient method for staghorn stone fragmentation and removal without requiring multiple percutaneous incisions or multiple procedures. Source of Funding: None © 2022 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 207Issue Supplement 5May 2022Page: e203 Advertisement Copyright & Permissions© 2022 by American Urological Association Education and Research, Inc.MetricsAuthor Information Micah Levy More articles by this author Chih Peng Chin More articles by this author Krishna T. Ravivarapu More articles by this author Osama Al-Alao More articles by this author Michael Palese More articles by this author Expand All Advertisement PDF DownloadLoading ...

Design and Analysis of a Three-Fingered Deployable Metamorphic Robotic Grasper

Abstract This paper presents the design and analysis of a three-fingered deployable metamorphic robotic grasper for manipulating large-scale unknown objects. This grasper is composed of three fingers and a single-mobility umbrella-shaped palmar mechanism. First, the mechanism-design of the grasper is introduced and the metamorphic-motion process is analyzed, followed by the structural optimization, the finger with three modules can be deployed from 111.5 mm to 304 mm, and the good deploy/fold ratio can reach 2.73. This equips the grasper with a compact folded configuration and a large deployed configuration. Second, kinematic models of the deployment motion and grasping motion are independently established, and kinematic analysis is conducted. To further illustrate kinematic performance, kinematic simulation for the grasper is then performed. Third, the condition of the stable grasp is analyzed; trajectory planning of the grasper based on an S-shaped acceleration and deceleration function algorithm is then carried out. Fourth, a control system is designed and a physical prototype is fabricated. Grasping experiments are then conducted to prove the ability of the grasper to grasp objects of various sizes and shapes.

Numerical investigation of a bioinspired multi-segment soft pneumatic actuator for grasping applications

Soft robotic gripper is useful for grasping applications, such as pick-and-place tasks, post-disaster rescue and health monitoring of civil infrastructure. Inspired by the versatility of the human hand and bird claws, this paper designed a bioinspired actuator made of multi-segment fibre-reinforced pneumatic bending actuator and bellow-shape pneumatic rotational actuator joints. A numerical model was established to investigate the bending performance and stress distribution of the designed actuator under different input pressures. The influences of bottom layer thickness, chamber number at the actuator joints, and bending segment length on the overall bending performance of the designed soft actuator have been comprehensively investigated. In addition, the stress distribution of the actuator joints has been studied for understanding the mechanical performance of the actuator joints. Finally, a soft gripper made of two designed actuators has been demonstrated for grasping objects with different shapes and weights. The findings found in this investigation are helpful for the design and fabrication of robotic grasper, which can be further integrated on an industrial robotic arm and flying robotic platform for grasping and prosthetic hand applications.

Adaptive Underactuated Finger With Active Rolling Surface

This letter presents the design, prototype and kinematic model of a new adaptive underactuated finger with an articulated skin/surface that is able to bend and, at the same time, provides active rolling motion along its central axis while keeping the finger configuration (see Fig. 1). The design is based on a planar chain of overlapping spherical phalanxes that are tendon-driven. The finger has an articulated surface made of an external chain of hollow universal joints that can rotate via its central axis on the surface of the internal structure. The outer surface provides a second active Degree of Freedom (DoF). The two actuators, driving the bending and/or rolling motion, can be used independently. A set of experiments have been included to validate and measure the performance of the prototype for the grasping and rolling actions. The proposed finger can be built with a different number of phalanxes and sizes. A number of these fingers can be arranged along a palm structure resulting in a multi-finger robotic grasper for applications that require adaptation and in-hand manipulation capabilities such as pHRI.

Robotic-assisted left lower-lobe pulmonary lobectomy: Eleven steps.

Robotic-assisted left lower-lobe pulmonary lobectomy: Eleven steps.

V-Shape Pneumatic Torsional Actuator: A Building Block for Soft Grasper and Manipulator.

Robotic joints are fundamental components in artificial graspers and manipulators, and they are designed to achieve high dexterity to carry out various tasks. Traditional robotic hands are often driven by rigid joints, such as tendons and electric motors, resulting in bulky and complex designs. Soft robotics, composed of flexible and compliant materials, offers promising solutions to mimic the human hands and handle delicate objects safely. In this article, we propose a simple yet effective V-shape pneumatic torsional actuator (V-PTA) as the building blocks of soft grasper and manipulators. The proposed actuator is capable of producing large angular changes and twisting torque, responding fast to pneumatic changes, and scaling to appropriate dimensions easily. Because the design is generic and modular in nature, these lightweight actuators could also be assembled to form a variety of patterns of structures to suit the needs of individual tasks. We further fabricated robotic graspers and manipulators based on multiple V-PTA and demonstrated that our design could offer solutions to execute daily laboratory operations that interact with small and irregular components. Experimental data confirmed that the V-PTA building block structure could potentially pave the path forward for miniature robotic automation in laboratory or industrial settings.

A Three-Limb Teleoperated Robotic System with Foot Control for Flexible Endoscopic Surgery.

Flexible endoscopy requires a lot of skill to manipulate both the endoscope and the associated instruments. In most robotic flexible endoscopic systems, the endoscope and instruments are controlled separately by two operators, which may result in communication errors and inefficient operation. Our solution is to enable the surgeon to control both the endoscope and the instruments. Here, we present a novel tele-operation robotic endoscopic system commanded by one operator using the continuous and simultaneous movements of their two hands and one foot. This 13-degree-of-freedom (DoF) system integrates a foot-controlled robotic flexible endoscope and two hand-controlled robotic endoscopic instruments, a robotic grasper and a robotic cauterizing hook. A dedicated foot-interface transfers the natural foot movements to the 4-DoF movements of the endoscope while two other commercial hand interfaces map the movements of the two hands to the two instruments individually. An ex-vivo experiment was carried out by six subjects without surgical experience, where the simultaneous control with foot and hands was compared with a sequential clutch-based hand control. The participants could successfully teleoperate the endoscope and the two instruments to cut the tissues at scattered target areas in a porcine stomach. Foot control yielded 43.7% faster task completion and required less mental effort as compared to the clutch-based hand control scheme, which proves the concept of three-limb tele-operation surgery and the developed flexible endoscopic system.

A Novel Design for a Compliant Mechanism Based Variable Stiffness Grasper Through Structure Modulation

Abstract Robots utilize graspers for interacting with an environment. Conventional robotic graspers have difficulty conforming to objects of varied shape and exerting varying grasping forces. Variable stiffness soft robotic graspers provide these features but face issues such as slow response time, the requirement of external power packs for operation and low variation of stiffness. A variable stiffness compliant robotic grasper that is simple in design and operation would improve end effectors used in assistive robotics and prostheses for handling a wide array of objects. In this paper, we present the design of a novel variable stiffness compliant robotic grasper that can change its stiffness through structural transformations. Current designs utilizing structural transformations do not provide shape conformance while grasping objects. We propose a design for a soft robotic grasper using the concept of stability of truss structures. This design is capable of partially conforming to the surface of an object being grasped and can rapidly vary its stiffness utilizing compliant rotating elements embedded in the grasper jaws. The grasper behavior is modeled using finite element analysis (FEA) and validated experimentally. Our results demonstrate that structural transformation of flexible elements is a potential solution for achieving variable stiffness in a grasper.

Sewing up the Wounds: A Robotic Suturing System for Flexible Endoscopy

If a perforation occurs as a result of a flexible endoscopic procedure, urgent laparoscopy or open surgery may be required to repair the perforation, because suturing is normally stronger than closure using existing endo-scopic devices. Suturing with stitches and knots, widely adopted in open or laparoscopic surgery, is still not possible in flexible endoscopy. This is due to the confined space of the natural orifice and target area, the high levels of motion dexterity and force needed for stitching and knot tying, and the critical size and strength requirements of wound closure. We present a novel flexible endoscopic robotic suturing system that can suture gastrointestinal defects without opening up the patient's body as in open or laparo scopic surgery. This system features a robotic needle driver and a robotic grasper, both of which are flexible, small enough for through-the-scope delivery, and dexterous with five degrees of freedom (DoF). The needle driver, facilitated by the grasper, enables the surgeon to control a needle through teleoperation and so make stitches and knots in flexible endoscopy. Successful in vivo trials were conducted in the rectum of a live pig to confirm the feasibility of endoscopic suturing and knot tying using the system in a realistic surgical scenario (not possible with existing devices, which are all manually driven) . This new technology will change the way surgeons close gastro intestinal defects.

Monopolar stray energy in robotic surgery.

Stray energy transfer from monopolar radiofrequency energy during laparoscopy can be potentially catastrophic. Robotic surgery is increasing in popularity; however, the risk of stray energy transfer during robotic surgery is unknown. The purpose of this study was to (1) quantify stray energy transfer using robotic instrumentation, (2) determine strategies to minimize the transfer of energy, and (3) compare robotic stray energy transfer to laparoscopy. In a laparoscopic trainer, a monopolar instrument (L-hook) was activated with DaVinci Si (Intuitive, Sunnyvale, CA) robotic instruments. A camera and assistant grasper were inserted to mimic a minimally invasive cholecystectomy. During activation of the L-hook, the non-electric tips of the camera and grasper were placed adjacent to simulated tissue (saline-soaked sponge). The primary outcome was change in temperature from baseline (°C) measured nearest the tip of the non-electric instrument. Simulated tissue nearest the robotic grasper increased an average of 18.3 ± 5.8°C; p < 0.001 from baseline. Tissue nearest the robotic camera tip increased (9.0 ± 2.1°C; p < 0.001). Decreasing the power from 30 to 15W (18.3 ± 5.8 vs. 2.6 ± 2.7°C, p < 0.001) or using low-voltage cut mode (18.3 ± 5.8 vs. 3.1 ± 2.1°C, p < 0.001) reduced stray energy transfer to the robotic grasper. Desiccating tissue, in contrast to open air activation, also significantly reduced stray energy transfer for the grasper (18.3 ± 5.8 vs. 0.15 ± 0.21°C, p < 0.001) and camera (9.0 ± 2.1 vs. 0.24 ± 0.34°C, p < 0.001). Stray energy transfer occurs during robotic surgery. The assistant grasper carries the highest risk for thermal injury. Similar to laparoscopy, stray energy transfer can be reduced by lowering the power setting, utilizing a low-voltage cut mode instead of coagulation mode and avoiding open air activation. These practical findings can aid surgeons performing robotic surgery to reduce injuries from stray energy.

Robotic Revision Of A Post-Whipple Hepaticojejunostomy Stricture After Previous Open Pancreatoduodenectomy

Presenter: Zayne Belal | Texas Tech University Health Sciences Center Background: Hepaticojejunostomy (HJ) is one of the three anastomoses made during a pancreatoduodenectomy (Whipple) procedure. A rare complication of a HJ anastomosis is a stricture, which is often symptomatic with pain, jaundice, cholangitis and potential biliary cirrhosis. The recommended initial treatment for this complication is to first attempt percutaneous dilations of the stricture and then perform surgical stricture revision if the percutaneous dilations fail. In this video, we describe a robotic approach to a post-Whipple resection hepaticojejunostomy stricture revision. Methods: A robotic camera with 3 robotic arms and an assistant trocar were used for the procedure. The omental attachments to the free edge of the right liver were released until the hepatic hilum was exposed. The jejunal loop anastomosed to the bile duct was encountered and released from the surrounding attachments until the hepaticojejunostomy was fully identified and circumferentially dissected. The presumed bile duct portion of the HJ was grasped with robotic graspers to confirm the indwelling PTC tube and HJ. The HJ anastomosis was then opened over the PTC tube with electrosurgery until the tube was exposed. The tube was then retracted and the associated debris, stones and stricture were removed. The entire HJ was then taken down after the PTC tube was removed. The bile duct orifice was examined; it was thick-walled and measured roughly 7-8 mm in diameter. The HJ stricture scar was excised completely. The same jejunotomy was used for re-anastomosis. A new HJ was created with running posterior and anterior layers of 4-0 Vicryl sutures on RB-1 needles. The patency of the anastomosis was confirmed using a robotic grasper. The anterior and posterior sutures were then tightened and tied, completing the new HJ anastomosis. Surgical drain was placed around the HJ. Results: The procedure time was 195 minutes with an estimated blood loss around 50 mL. The patient had an uneventful recovery postoperatively, and was discharged on post-operative day 2. The patient is currently doing well at 9 months postoperatively and will be followed up as needed. Conclusion: Robotic hepaticojejunostomy stricture revision post-pancreatoduodenectomy feasible procedure. Previous open surgery should not contraindicate an attempt at minimally invasive repair if appropriate MIS/HPB skills and expertise is available.Robotic approach is had additional advantages in surgical dexterity due to increased range of motion/degrees of freedom, reduced surgeon fatigue and enhanced 3D visualization. Both access to a surgical robot and appropriately trained HPB surgeons are necessary to perform this procedure. This is often limited to large tertiary hepato-pancreato-biliary (HPB) surgery centers.

Intraoperative hemorrhage control during robot-assisted pancreatoduodenectomy

Introduction: Pancreatoduodenectomy is increasingly performed minimally invasively. The main advantage of robotic pancreatoduodenectomy (RPD), compared to laparoscopy, is control of intraoperative hemorrhage avoiding unnecessary conversion to laparotomy. Methods: Consecutive RPDs were collected in a prospectively maintained database. Video recordings were evaluated of RPDs with an intraoperative estimated blood loss (EBL) exceeding 1000cc. The recordings were evaluated for the timing, cause, source, and duration of the bleeding, as well as the method and outcome of bleeding control. Results: During a two-year period (2017-2018), the initial 64 RPD’s in a single center were performed. Baseline characteristics show a median age of 69 years, median BMI of 24.88 kg/m2, and pancreatic cancer diagnosis in 47%. All resections were completed robotically without conversion to laparotomy. Postoperative mortality was 1.6% and 13 patients (20%) had a grade B/C pancreatic fistula. The median EBL was 250cc (IQR:150-463). 5 patients had an EBL of more than 1000 ml. These patients all had a major venous bleeding from the portal vein, splenic vein, or superior mesenteric vein. Bleeding was initially controlled by closing the venous defect with a robotic grasper, because it could not be controlled by applying a gauze and pressure. Next, inflow and outflow were controlled with bulldogs and the defect was closed with interrupted sutures. Conclusion: Intraoperative hemorrhage control with RPD is safe and feasible even during the learning curve and avoids conversion to laparotomy.

Design and Analysis of a Novel Truss-Shaped Variable-Stiffness Deployable Robotic Grasper

This paper presents a novel truss-shaped variable-stiffness deployable robotic grasper to grasp large unknown objects, the grasper comprises a series of basic modules and has the advantages of a large workspace, adjustable stiffness, and a high deploy/fold ratio. First, detailed mechanism designs of the grasper and variable-stiffness joint are introduced, and a mobility analysis and variable stiffness analysis are conducted. Second, the structural analysis of the basic module is carried out, by which several major indices, including deploy/fold ratio, grasping angle, deployment angle, grasping torque, and deployment torque, can be calculated. Third, kinematic analysis is presented to provide the workspace and kinematic simulation, and then the joint trajectory planning based on fifth-order polynomial is also conducted. Fourth, the condition of stable grasp is analyzed and a mathematical model of grasping motion is established. Adam optimization algorithm is then applied to optimization of the mathematical model and a grasping simulation is performed with objects of various sizes and for various working states of the variable-stiffness joint. Finally, a simple physical prototype is fabricated, and variable-stiffness experiments and grasping experiments confirm that the proposed grasper shows excellent grasping performance.

Force Sensing With 1 mm Fiber Bragg Gratings for Flexible Endoscopic Surgical Robots

This article presents a novel force sensor to detect the distal force of tendon-sheath mechanisms (TSMs) in flexible endoscopic surgical robots. We propose to measure the compression force on the sheath at the distal end so that the tension force on the tendon, which equals the compression force on the sheath, can be obtained. With this approach, a new force sensor made up of a 1 mm fiber Bragg grating attached to a 3 mm long nitinol tube was developed to measure the compression force exerted on the sheath. Mechanics analysis and verification tests were conducted to characterize the relationship between tension and compression on a TSM. Force calibrations, hysteresis study, and temperature compensation verification tests on the sensor were carried out. The force sensor has a measurement error of 0.178 N and a sensitivity of 34.14 pm/N. Applications of the sensor in a TSM-driven robotic grasper and a tendon-driven continuum robot were demonstrated. This force sensor has salient advantages: it is small, structurally simple, electrically passive, temperature-compensated, easy to assemble and disassemble, flexible, and biocompatible. This proposed approach with the new force sensor can also be applied to both TSM-driven systems and tendon-driven systems such as robotic fingers/hands, wearable devices, surgical catheters, and rehabilitation devices.