Robotic Suturing Research Articles

Sa2062 TRANSANAL ENDOSCOPIC SUBMUCOSAL DISSECTION USING THE FLEX® ROBOTIC SYSTEM (MEDROBOTICS) BY A GASTROENTEROLOGIST: A CASE SERIES

Precancerous rectal lesions not amenable to standard mucosal resection and early T1a cancers are effectively treated with endoscopic submucosal dissection. Recently, a robotic endoscope with potential to expand and improve efficiency of transanal procedures has been approved by the FDA for transanal use. This scope provides access for two accessories capable of multiple freedoms of movement allowing effective dissection of tissue. The endoscopic surgeon uses both his hands, divorced from the scope controls for the dissection. We present the first case series of a gastroenterologist using the Flex® Robotic System for endoscopic submucosal resection of advanced rectal lesions. A retrospective review of patients was approved by the Institutional Review Board at Penn State Hershey Medical Center. Clinical data for the 7 consecutive patients was collected including length of the procedure, length of stay, location of mass, size of mass, and details of the procedure. Data on patient demographics including BMI, age, and ASA score were also collected. Procedural notes from prior to the robotic resection, the robotic resection itself, and follow-up endoscopic evaluation after robotic resection were all reviewed. Of the 7 patients listed for procedure, 2 cases were abandoned; one due to evidence of T2 cancer and another due to anal stenosis. Among the rest, 3 used the robotic device alone while 2 of the cases used traditional ESD in addition to the robotic device. Reasons for needing to use conventional methods included equipment issues with suctioning using the robotic device and need for improved visualization of a bleed occurring in a difficult location. Average age of the patients was 62, BMI was 30, and ASA score was 3. Average size of the lesions resected was 4.4cm x 5.0cm. Final pathology included one tubulovillous adenoma, one tubular adenoma with high grade dysplasia, one tubulovillous adenoma with high grade dysplasia, and two with adenocarcinoma. The robotic scope represents a true advancement in the endoscopic surgical platform. Advantages of the robotic system include the ability to use traction and counter-traction which allow for precise control and ease of dissection as well as stabilization of the resection field, allowing for faster dissection with seemingly less bleeding. In addition, the 3D vision of the robotic system allows for excellent sense of tissue planes, even without the use of submucosal elevation. Disadvantages include the need for anal dilation and general anesthesia. The current robot lacks suction and submucosal injection capabilities. Additional weaknesses include limited length reached within the rectum and maneuverability of the device. With improvement of technique and technology, endoscopists skilled in both conventional and robotic ESD could minimize the need for proctectomy.Figue 2Endoscopic robotic suturing after dissection of the rectal mass lesionView Large Image Figure ViewerDownload Hi-res image Download (PPT)

Constrained-Space Optimization and Reinforcement Learning for Complex Tasks

Learning from Demonstration is increasingly used for transferring operator manipulation skills to robots. In practice, it is important to cater for limited data and imperfect human demonstrations, as well as underlying safety constraints. This paper presents a constrained-space optimization and reinforcement learning scheme for managing complex tasks. Through interactions within the constrained space, the reinforcement learning agent is trained to optimize the manipulation skills according to a defined reward function. After learning, the optimal policy is derived from the well-trained reinforcement learning agent, which is then implemented to guide the robot to conduct tasks that are similar to the experts' demonstrations. The effectiveness of the proposed method is verified with a robotic suturing task, demonstrating that the learned policy outperformed the experts' demonstrations in terms of the smoothness of the joint motion and end-effector trajectories, as well as the overall task completion time.

A preliminary evaluation of two different meshes in minimally invasive inguinal hernia surgery.

Many meshes are available for use in laparoscopic inguinal hernia repair. The surgeon must consider several factors when choosing a mesh for hernia repair including clinical outcomes, cost, and ease of use. The purpose of this study was to compare two different lightweight polypropylene meshes for laparoscopic and robotic inguinal hernia repairs. Subjects were randomized immediately before surgery. Data were reported in N (%) and median [Q1-Q3], comparisons of mesh insertion time were tested using a 2 × 2 ANOVA on the ranked times, comparisons between categorical variables were tested with Fisher's Exact, and all data were analyzed using SAS® 9.4 (SAS Institute, Inc.). Between January 2015 and June 2016, 50 subjects were enrolled; two were excluded. Of 48 eligible subjects, most were Caucasian (N = 42, 88%), male (N = 37, 77%), with a median age of 63, and were randomized evenly between 3DMax™ mesh and Ultrapro® mesh. Robotic mesh placement significantly increased insertion time regardless of mesh type (p < .0001). When comparing NASA-TLX self-assessment surveys, there was no significant difference between the meshes in difficulty of placement. The type of mesh did not significantly impact the insertion time regardless of robot use (p = 0.523). Our data demonstrate that mesh insertion times comparing two different lightweight polypropylene meshes were not significantly different. Increased insertion times associated with robotic repair are likely due to the mechanics of robotic suturing and associated learning curve. Our data suggest that these meshes can be used interchangeably based on the surgeon's preference. NCT01825187.

Microsurgical robotic suturing of sural nerve graft for sympathetic nerve reconstruction: a technical feasibility study.

Endoscopic thoracic sympathectomy (ETS) may provide a permanent surgical cure for primary palmar hyperhidrosis. Unfortunately, some patients can experience intensive post-operative compensatory sweating (CS) that ultimately impairs quality of life. Sympathetic nerve reconstruction (SNR) may be used to counteract severe post-operative CS through the restoration of sympathetic pathways. In this case series, we describe the technical feasibility of a robot-assisted micro-peripheral nerve reconstruction method for achieving SNR in patients with post-operative CS. Between January 2017 and May 2019, seven cases with severe post-operative CS underwent robot-assisted SNR using a sural nerve graft. We report the pre-operative assessment, the surgical technique, and the clinical outcomes of the study patients. The study sample consisted of five men and two women (median age: 41 years). Primary hyperhidrosis affected the face in one case and the palms in six patients. The median time between ETS and SNR was 20 years. All robotic surgery procedures were successfully accomplished, and neither conversion to open surgery nor the creation of additional ports were required. Sural nerve grafts (median length: 8 cm) were used in all cases, and the median operating time was 10.5 h. There was no operative mortality, with the median length of post-operative hospital stay being 4 days. One patient developed a post-operative pneumothorax-which was treated conservatively. Our case series demonstrates the safety and clinical feasibility of microsurgical robot-assisted sural nerve grafting for achieving SNR in patients with post-operative CS.

Developing an intelligent tutoring system for robotic-assisted surgery instruction.

Robotic-assisted laparoscopic surgery (RALS) is an operative innovation that has sparked global interest. Over the last decade, RALS cases have rapidly increased with over 750000 robotic procedures completed in 2017. Until recently, Intuitive's da Vinci surgical system has been the only Food and Drug Administration (FDA)-approved robotic-assisted surgical device for human procedures. Robotic procedures with the da Vinci require a specific, dedicated training due to the introduction of the technological components and psychomotor skills needed to successfully utilize this system. When a surgeon becomes interested in learning robotics, there are limited avenues for training. Surgeons typically receive instruction on the necessary psychomotor and Operation Room (OR) communication skills in isolation from the cognitive and perceptual skills and may only perform these skills in an integrated manner during a 1- or 2-day course. This paper discusses the development of a computer-based intelligent tutoring system (ITS) to train the cognitive and procedural skills needed to complete basic robotic suturing to novice robotic surgeons. The system was developed using the generalized intelligent framework for tutoring framework of tools. This information was captured as video, instruction sets, and flowcharts, which were reviewed for accuracy by surgeons and then encoded into an ITS using the generalized intelligent framework for tutoring tools. The purpose of this paper was threefold-(a) explain the process used to obtain the critical data behind a basic robotic task, (b) develop an entry-level ITS to train the cognitive process and procedural steps behind multiple fundamental robotic surgery skills, and (c) provide future novice ITS developers lessons learned and future recommendations beyond the initial ITS prototype.

Gender differences in the acquisition of suturing skills with the da Vinci surgical system

The percentage of female medical students has been significant elevating worldwide. The demographic shift is expected to influence the proportion of male versus female surgeons soon. The objective of this study was to evaluate the gender differences in the acquisition of robotic suturing skills. We compared the robotic suturing performance between 39 male and 19 female medical students. We separated the training into two parts: phase I, involving virtual reality (VR) robotic simulation, and phase II, involving robotic dry-laboratory simulation training. Participants first conducted step-by-step exercises on the VR robotic simulator and then the robotic skin-suturing pad using the da Vinci robot. The metric analysis of the VR task "suture sponge" showed that female students required less time (difference: -170.7 seconds, 95% CI: -247.4 to -94.0) and had fewer errors (error difference: -50, 95% CI: -74.2 to -25.8) to complete the suture sponge exercise compared to male students. Moreover, female students completed more stitches than male students (differences in mean stitch achieved: .35; 95% CI: .06 to .65). However, there was no difference in the quality scores of stitches by gender (p=0.85). Female medical students performed better in the VR task of suture spongy and achieved more stitches than male students with the da Vinci system despite no difference in robotic suture quality by gender. Because this is the first study comparing gender performance on a robotic platform, further studies are required to investigate if different training approaches will affect the performance by gender.

An Efficient Single-session Spatial Skill Trainer for Robot-assisted Surgery: A Randomized Trial

To introduce and examine a single session of spatial skill training as an efficient means of improving surgical suturing performance in robot-assisted surgery. A randomized, controlled trial. A tertiary university medical center in Israel. A purposive sample composed of 41 residents with no robotic suturing skills. A computer-based simulator training of spatial skills. Participants were randomly assigned to training (n = 21: mean age of 34 years [standard deviation (SD) = 1.92]) and control (n = 20: mean age of 32 years [SD = 3.17]) conditions. The training group underwent a session of spatial skills training, whereas the control group engaged in a neutral activity. After 1 participant was lost to the follow-up of the posttraining performance test, data of 40 participants were analyzed. Robotic suturing task performance with the da Vinci Skills Simulator (Intuitive Surgical, Sunnyvale, CA) was evaluated using the da Vinci Skills Simulator built-in measure of "excess tissue piercing" and an expert rating of "tissue tearing." The mean number of excess tissue piercing after training (but not after the neutral activity) was significantly lower than before training (3.25 [SD = 1.996] vs 6.75 [SD = 3.68], respectively; p <.001), reflecting an improvement of 52% (decreasing the mean number of excess tissue piercing in a single suture by 3.5 excess piercing trials). After the interventions, the extent of tissue tearing was rated lower in the training group (p = .01), and there was no change in the control group (p = .14). We showed the efficiency of a training approach that focuses on spatial skills critical in robot-assisted surgery. We showed that surgeons who received a 1 session spatial skill training with a cognitive spatial skill trainer immediately improved the performance of a robotic suturing task compared with surgeons who did not receive such training.

Autonomous Laparoscopic Robotic Suturing with a Novel Actuated Suturing Tool and 3D Endoscope.

Compared to open surgical techniques, laparoscopic surgical methods aim to reduce the collateral tissue damage and hence decrease the patient recovery time. However, constraints imposed by the laparoscopic surgery, i.e. the operation of surgical tools in limited spaces, turn simple surgical tasks such as suturing into time-consuming and inconsistent tasks for surgeons. In this paper, we develop an autonomous laparoscopic robotic suturing system. More specific, we expand our smart tissue anastomosis robot (STAR) by developing i) a new 3D imaging endoscope, ii) a novel actuated laparoscopic suturing tool, and iii) a suture planning strategy for the autonomous suturing. We experimentally test the accuracy and consistency of our developed system and compare it to sutures performed manually by surgeons. Our test results on suture pads indicate that STAR can reach 2.9 times better consistency in suture spacing compared to manual method and also eliminate suture repositioning and adjustments. Moreover, the consistency of suture bite sizes obtained by STAR matches with those obtained by manual suturing.

Designing, Prototyping, and Testing a Flexible Suturing Robot for Transanal Endoscopic Microsurgery

Suturing and knot tying in a confined space is a technically challenging yet clinically demanding task in minimally invasive surgery, which requires the use of highly articulated instruments passing through small incisions on the patient's body. Manually operating such instruments is usually very difficult, so robot-assisted methods have been introduced to reduce the burden of the surgeon. In this letter, a robotic suturing system for simplifying suturing in a confined space is proposed. The main part of the suturing robot is a 6-mm flexible suturing instrument that consists of suturing probe and a customized flexible joint. A novel needle driving and locking mechanism have been proposed. For controlling the suturing robot with teleoperation, the kinematics of the robot and its differential Jacobian as well as inverse kinematics are provided. A working prototype of the suturing instrument is built and integrated into a teleoperated suturing system. Running stitch and knot tying experiments have been conducted to evaluate the robot's feasibility for suturing in a confined space, which mimics the transanal endoscopic microsurgery procedure.

Endoscopic robotic suturing: The way forward.

Traditionally, suturing is performed in open surgery using a needle holder and forceps. The aim is to achieve accurate approximation of both edges of the wound and to tie a secure knot. With the development of laparoscopic surgery, traditional suturing methods have been adapted to meet the constraints of rigid laparoscopic instruments with limited degrees of freedom. The subsequent introduction of three-dimensional robotic suturing has since made intracorporeal suturing easier to learn, primarily because of its intuitiveness and the additional degree of freedom of the robotic wrists. With the increasing popularity of therapeutic endoscopic procedures for early gastrointestinal cancers, devices allowing for endoscopic suturing have since been developed. Nevertheless, these devices remain challenging to use as they require double-channel endoscopes and do not have the extra degree of freedom of robotic wrists. The introduction of robotics to the field of endoscopic suturing has proven to be promising. This review describes the development and adaptation of basic suturing techniques to various platforms, such as laparoscopic, robotic and endoscopic.

Objective assessment of robotic suturing skills with a new computerized system: A step forward in the training of robotic surgeons.

The purpose of this study was to assess robot-assisted suturing skills on a laparoscopic intestinal anastomosis model by using a novel computerized objective assessment system. This study compared the suturing skills of 13 surgically naïve participants on an artificial intestinal anastomosis model that mimics real tissue. Each examinee sutured using da Vinci robot assistance under 2-D and 3-D visualization and with conventional laparoscopy (CL). Pressure-measuring and image-processing devices were employed to quantitatively evaluate suturing skills. Five unique criteria were used to evaluate the skills of participants. Suturing under 3-D visualization (P < 0.01) and with CL (P < 0.05) were significantly faster than under 2-D visualization. Sutures placed under 3-D (P < 0.05) and 2-D (P < 0.01) visualization had significantly better suture tension than those placed with CL, which did not meet acceptable values for suture tension. Sutures placed with CL had significantly better air pressure leakage than those placed under 2-D visualization (P < 0.05), which did not meet acceptable values for air pressure leakage and wound opening area. One participants failed to achieve full-thickness sutures with 2-D, two participants with CL, and one participant with 3-D. Using 3-D vision is necessary for complex maneuvering during robot-assisted minimally invasive surgery. Our quantitative assessment system is useful for evaluating the skill acquisition of surgeon-trainees undergoing robotic surgery training.

Robotic Surgery Improves Technical Performance and Enhances Prefrontal Activation During High Temporal Demand

Robotic surgery may improve technical performance and reduce mental demands compared to laparoscopic surgery. However, no studies have directly compared the impact of robotic and laparoscopic techniques on surgeons’ brain function. This study aimed to assess the effect of the operative platform (robotic surgery or conventional laparoscopy) on prefrontal cortical activation during a suturing task performed under temporal demand. Eight surgeons (mean age ± SD = 34.5 ± 2.9 years, male:female ratio = 7:1) performed an intracorporeal suturing task in a self-paced manner and under a 2 min time restriction using conventional laparoscopic and robotic techniques. Prefrontal activation was assessed using near-infrared spectroscopy, subjective workload was captured using SURG-TLX questionnaires, and a continuous heart rate monitor measured systemic stress responses. Task progression scores (au), error scores (au), leak volumes (mL) and knot tensile strengths (N) provided objective assessment of technical performance. Under time pressure, robotic suturing led to improved technical performance (median task progression score: laparoscopic suturing = 4.5 vs. robotic suturing = 5.0; z = − 2.107, p = 0.035; median error score: laparoscopic suturing = 3.0 mm vs. robotic suturing = 2.1 mm; z = − 2.488, p = 0.013). Compared to laparoscopic suturing, greater prefrontal activation was identified in seven channels located primarily in lateral prefrontal regions. These results suggest that robotic surgery improves performance during high workload conditions and is associated with enhanced activation in regions of attention, concentration and task engagement.

Fundoplication with 180-Degree Wrap During Esophagogastrostomy After Robotic Proximal Gastrectomy for Early Gastric Cancer

BackgroundCompared with total gastrectomy, proximal gastrectomy (PG) has potential advantages from a nutritional perspective, such as anemia and postoperative loss of body weight. However, PG is associated with some postoperative functional disorders, such as reflux esophagus (13–31%) and anastomotic stenosis (3–29%).1 We therefore developed a new procedure for fundoplication during esophago-gastrostomy after robotic PG (RPG). MethodsWe performed RPG for early gastric cancer localized in the upper third of the stomach using the da Vinci Surgical System (Intuitive, Sunnyvale, CA). After RPG conclusion, intracorporeal esophago-gastrostomy was performed by side-to-side anastomosis using a linear 45 mm stapling device, Endo GIA purple cartridge.2 The post-excisional hole in the esophago-gastrostomy was closed with interrupted single-layered sutures by robotic suturing technique. Fundoplication was created by wrapping the remnant stomach around 180 degrees of the circumference of the esophagus; the remnant stomach was wrapped from the esophageal posterior wall towards the esophageal anterior wall. Four stitches were used for fixation. We did not add a bougie of esophago-gastrostomy when fashioning the wrap. In addition, we did not perform pyloroplasty. ResultsIn our series with 15 patients, there were no postoperative complications. No patients had reflux symptoms. Our technique using the fundoplication with “clockwise” rotation attempts to prevent reflux by use of intragastric pressure to flatten the lower end of the esophagus into a valvate shape. Indeed, in fluoroscopic findings 4 days after surgery, there was no reflux to the esophagus of the contrast medium. In endoscopic findings 3 months after surgery, anastomotic stenosis was absent. We observed no endoscopic findings of reflux esophagitis. Formation of the pseudo-fornix was confirmed by wrapping the remnant stomach. ConclusionsRPG followed by fundoplication with 180-degree wrap may be a promising procedure for reflux esophagitis prevention.3,4 However, long-term follow-up is required to show benefits of this new procedure.4

Computational Modeling of Wound Suture: A Review.

Suturing is an acquired skill which is based on a surgeon's experience. To date, no two sutures are the same with respect to the type of knot, tension, or suture material. With advancement in medical technologies, robotic suturing is becoming more and more important to operate on complex and difficult to reach internal surgical sites. While it is very difficult to translate a surgeon's suturing expertise to an automated environment, computational models could be employed to estimate baseline suture force requirements for a given wound shape, size, and suture material, which could be subsequently processed by a robot. In the literature, there have been few attempts to characterize wound closure and suture mechanics using simple two- and three-dimensional computational models. Single and multiple skin layers (epidermis, dermis, and hypodermis) and tissues with different wound geometries and sizes have been simulated under simple wound flap displacements to estimate suture force requirements. Also, recently, sutures were modeled to simulate a realistic wound closure via suture pulling, and skin prestress effect due to the natural tension of skin was incorporated in a few models to understand its effects on wound closure mechanics. An extensive review of this literature on computational modeling of wound suture would provide valuable insights into the areas in which further research work is required. Discussion of various computational challenges in modeling sutures in a numerical environment will help in better understanding the roadblocks and the required advancements in suture modeling.

The Effect of Visual-Spatial Ability on the Learning of Robot-Assisted Surgical Skills

The aim of this study was to determine the correlation of visual-spatial ability with progression along the learning curve for robotic surgical skills training. A total of 21 novice participants were recruited. All participants completed a training program consisting of 5 training sessions of 30 minutes of virtual reality (VR) simulation and 30 minutes of dry laboratory training. The VR simulation part was the subject of the present study. During VR simulation training, participants performed the basic skill exercises of Camera Targeting 1, Pick and Place, and Peg Board 1 followed by advanced skill exercises of Suture Sponge 1 and Thread the Rings. The visual-spatial ability was assessed using a mental rotation test (MRT). Pearson correlation coefficients were used to assess the relationship between the MRT score and simulator score for the aforementioned 5 tasks. Student t test was used to compare the simulator score between high- and low-MRT score groups. A median MRT score of 26/40 (range: 13-38) was observed. Approximately 19 participants completed the full curriculum but 2 did not complete "Thread the Rings" during the study period. A significant correlation was observed between the MRT score and simulator score only in "Suture Sponge 1" over the first 3 attempts (first: r = 0.584, p = 0.0054; second: r = 0.443, p = 0.0443; third: r = 0.4458, p = 0.0428). After the third attempt, this significant correlation was lost. Comparison of the score for "Suture Sponge 1" between the high-MRT and low-MRT scoring participants divided by a median MRT score of 26 also showed a significant difference in the score until the third trial. Our observations suggest that the spatial cognitive ability influences the initial learning of robotic suturing skills. Further studies are necessary to verify the usefulness of an individual's spatial ability to tailor the surgical training program.

Transferability of Virtual Reality, Simulation-Based, Robotic Suturing Skills to a Live Porcine Model in Novice Surgeons: A Single-Blind Randomized Controlled Trial

Study ObjectiveTo assess whether a robotic simulation curriculum for novice surgeons can improve performance of a suturing task in a live porcine model. DesignRandomized controlled trial (Canadian Task Force classification I). SettingAcademic medical center. PatientsThirty-five medical students without robotic surgical experience. InterventionsParticipants were enrolled in an online session of training modules followed by an in-person orientation. Baseline performance testing on the Mimic Technologies da Vinci Surgical Simulator (dVSS) was also performed. Participants were then randomly assigned to the completion of 4 dVSS training tasks (camera clutching 1, suture sponge 1 and 2, and tubes) versus no further training. The intervention group performed each dVSS task until proficiency or up to 10 times. A final suturing task was performed on a live porcine model, which was video recorded and blindly assessed by experienced surgeons. The primary outcomes were Global Evaluative Assessment of Robotic Skills (GEARS) scores and task time. The study had 90% power to detect a mean difference of 3 points on the GEARS scale, assuming a standard deviation (SD) of 2.65, and 80% power to detect a mean difference of 3 minutes, assuming an SD of 3 minutes. Measurements and Main ResultsThere were no differences in demographics and baseline skills between the 2 groups. No significant differences in task time in minutes or GEARS scores were seen for the final suturing task between the intervention and control groups, respectively (9.2 [2.65] vs 9.9 [2.07] minutes, p = .406; and 15.37 [2.51] vs 15.25 [3.38], p = .603). The 95% confidence interval for the difference in mean task times was –2.36 to .96 minutes and for mean GEARS scores −1.91 to 2.15 points. ConclusionsLive suturing task performance was not improved with a proficiency-based virtual reality simulation suturing curriculum compared with standard orientation to the da Vinci robotic console in a group of novice surgeons.

C-SATS: Assessing Surgical Skills Among Urology Residency Applicants.

We hypothesized that surgical skills assessment could aid in the selection process of medical student applicants to a surgical program. Recently, crowdsourcing has been shown to provide an accurate assessment of surgical skills at all levels of training. We compared expert and crowd assessment of surgical tasks performed by resident applicants during their interview day at the urology program at the University of California, Irvine. Twenty-five resident interviewees performed four tasks: open square knot tying, laparoscopic peg transfer, robotic suturing, and skill task 8 on the LAP Mentor™ (Simbionix Ltd., Lod, Israel). Faculty experts and crowd workers (Crowd-Sourced Assessment of Technical Skills [C-SATS], Seattle, WA) assessed recorded performances using the Objective Structured Assessment of Technical Skills (OSATS), Global Evaluative Assessment of Robotic Skills (GEARS), and the Global Operative Assessment of Laparoscopic Skills (GOALS) validated assessment tools. Overall, 3938 crowd assessments were obtained for the four tasks in less than 3.5 hours, whereas the average time to receive 150 expert assessments was 22 days. Inter-rater agreement between expert and crowd assessment scores was 0.62 for open knot tying, 0.92 for laparoscopic peg transfer, and 0.86 for robotic suturing. Agreement between applicant rank on skill task 8 on the LAP Mentor assessment and crowd assessment was 0.32. The crowd match rank based solely on skills performance did not compare well with the final faculty match rank list (0.46); however, none of the bottom five crowd-rated applicants appeared in the top five expert-rated applicants and none of the top five crowd-rated applicants appeared in the bottom five expert-rated applicants. Crowd-source assessment of resident applicant surgical skills has good inter-rater agreement with expert physician raters but not with a computer-based objective motion metrics software assessment. Overall applicant rank was affected to some degree by the crowd performance rating.

Experiment study on puncture force between MIS suture needle and soft tissue

Abstract In this paper, the interactive action between minimally invasive surgical suture needle and soft tissue was investigated under different insertion velocities, needle geometries, insertion angles and tissue characteristics to simulate the real surgical suture needle-tissue operation conditions. Experimental results demonstrated that the process of insertion was divided into two phases: no break phase and break phase. The puncture force generated at the mutation point where the tissue surface was breached. The puncture force and time for the first puncture significantly decreased with the increasing insertion velocity. The needle with triangle cross-section tip and larger size showed higher puncture force than that with round cross-section and smaller one. The penetration force reduced evidently with the advancing insertion angle, and it reached the lowest value when the angle is 90°. Moreover, an empirical single-parameter model of third-degree polynomial could predict the stiffness when a suture needle inserted into a complex soft tissue and showed a good fit to the experiment data. The results would provide reliable and significant mechanical database for the design of force feedback system in the surgical suture, either in endoscopic surgery or robotic suturing.

Randomized path planning for tasks requiring the release and regrasp of objects

This paper presents a randomized planning algorithm for manipulation tasks that require the robot to release and regrasp an object in different robot postures. Such problems arise, for example, in robotic suturing and knot tying, and in assembly tasks where parts must be guided through complex environments. Formulating the problem as one of planning on a foliated manifold, we present a randomized planning algorithm that, unlike existing methods, involves sampling and tree propagation primarily in the task space manifold; such an approach significantly improves computational efficiency by reducing the number of projections to the constraint manifold, without incurring any significant increases in the number of release-regrasp sequences. We also propose a post-processing topological exploration algorithm and path refinement procedure for reducing the number of release-regrasp sequences in a solution path, independent of the algorithm used to generate the path. Experiments involving spatial open chains with up to 10 degrees of freedom, operating in complex obstacle-filled environments, show that our algorithm considerably outperforms existing algorithms in terms of computation time, path length, and the number of release-regrasp operations.

Underwater robotic suturing

Background Laparoscopic and robotic surgeries have become popular, and this popularity is increasing. However, the environment in which such surgeries are performed is rarely discussed. Similar to arthrosurgery performed in water, artificial ascites could be a new environment for laparoscopic surgery. This study was performed to determine whether robotic surgery is applicable to complicated suturing underwater. Material and methods A da Vinci Surgical System S was used. A weighted fabric sheet was placed at the bottom of a tank. Identical sets were made for each environment: One tank was dry, and the other was filled with water. The suturing task involved placement of a running silk suture around the perimeter of a small circle. The task was performed eight times in each environment. The task time and integrity score were determined. The integrity score was calculated by evaluating accuracy, tightness, thread damage, and uniformity; each factor was evaluated using a five-point scale. Results Although statistically significant differences were not shown in either task time or integrity score between the underwater and air environments, robotic suturing underwater is not inferior to performance in air. Conclusions The feasibility of robotic suturing underwater was confirmed under the herein-described experimental conditions.