Tissue palpation in endoscopy using EIT and soft actuators.

The integration of soft robots in medical procedures has significantly improved diagnostic and therapeutic interventions, addressing safety concerns and enhancing surgeon dexterity. In conjunction with artificial intelligence, these soft robots hold the potential to expedite autonomous interventions, such as tissue palpation for cancer detection. While cameras are prevalent in surgical instruments, situations with obscured views necessitate palpation. This proof-of-concept study investigates the effectiveness of using a soft robot integrated with Electrical Impedance Tomography (EIT) capabilities for tissue palpation in simulated in vivo inspection of the large intestine. The approach involves classifying tissue samples of varying thickness into healthy and cancerous tissues using the shape changes induced on a hydraulically-driven soft continuum robot during palpation. Shape changes of the robot are mapped using EIT, providing arrays of impedance measurements. Following the fabrication of an in-plane bending soft manipulator, the preliminary tissue phantom design is detailed. The phantom, representing the descending colon wall, considers induced stiffness by surrounding tissues based on a mass-spring model. The shape changes of the manipulator, resulting from interactions with tissues of different stiffness, are measured, and EIT measurements are fed into a Long Short-Term Memory (LSTM) classifier. Train and test datasets are collected as temporal sequences of data from a single training phantom and two test phantoms, namely, A and B, possessing distinctive thickness patterns. The collected dataset from phantom B, which differs in stiffness distribution, remains unseen to the network, thus posing challenges to the classifier. The classifier and proposed method achieve an accuracy of 93 % and 88.1 % on phantom A and B, respectively. Classification results are presented through confusion matrices and heat maps, visualising the accuracy of the algorithm and corresponding classified tissues.

Development and validation of a virtual teaching method for minimally invasive surgery skills: a prospective cohort study.

INTRODUCTION: The COVID-19 pandemic led to a significant reduction in operative exposure for surgical trainees, necessitating alternative training methods to mitigate the impact on surgical education. This study sought to evaluate whether minimally invasive surgery (MIS) skills could be taught remotely using widely available technology with objective assessments of proficiency. METHODS: This was a pilot observational study with comparative assessment of face-to-face (F2F) and virtual training of novice learners in MIS skills. Performance and objective cognitive workload parameters (Surgical Task Load Index (SURG-TLX) score, heart rate and pupil metrics) were evaluated. The assessments were peg transfer (McGill Inanimate System for Training and Evaluation of Laparoscopic Skills (MISTELS)) and suturing (Suturing Training and Testing (SUTT)) tasks performed using box trainers. Virtual teaching was conducted by expert trainers using a web-based streaming platform. RESULTS: Technical challenges of delivering a virtual MIS skills course were addressed after a pilot course. Participants (n = 20) in the final course had similar baseline characteristics and were randomly allocated to F2F (n = 8) and virtual (n = 12) teaching groups. Participants in the online group completed the peg transfer task faster than the F2F group (11.25 minutes vs. 16.88 minutes; P = 0.015). There were no significant differences in all other MISTELS and SUTT performance measures between groups. Cognitive workload parameters (SURG-TLX score, heart rate and pupil metrics) were also similar between groups. CONCLUSION: This study has demonstrated that virtual teaching of MIS skills using a web-based streaming platform is feasible and effective, providing the foundation for low-cost, effective, and scalable MIS skills programs in the future.

A snapshot audit of global flexible endoscopy practice among European Association of Endoscopic Surgeons (EAES) and Society of American Gastrointestinal and Endoscopic Surgeons (SAGES) surgeons from the EAES Flexible Endoscopy Subcommittee survey.

INTRODUCTION: Endoscopy is an essential skill for all surgeons. However, endoscopic competency, training, and practice may vary widely among them. The EAES Flexible Endoscopy Subcommittee is working towards a standardized set of fundamental endoscopic knowledge and skills. To best advise on current practice patterns of flexible endoscopy among surgeons worldwide, a snapshot audit was conducted on the training, use, and limitations of flexible endoscopy in practice. METHODS: An online survey was distributed via email distribution and social media platforms for EAES, SAGES, and WebSurg members. Respondent demographics, training, and practice patterns were assessed. The main outcome measure was the annual endoscopic volume. Multivariate regression and machine learning models analyzed relationships between outcomes and independent variables of age, geographic region, laparoscopic surgery practice, and surgical specialization. RESULTS: A total of 1486 surgeons from 195 countries completed the survey. Respondents were mainly general (n = 894/1486, 60.2%), colorectal (n = 189/1486, 12.7%), bariatric (n = 117/1486, 7.9%), upper gastrointestinal (GI)/foregut (n = 108, 7.3%), hepatobiliopancreatic/HPB (n = 59/1486, 4%), and endocrine surgeons (n = 11/1486, 0.7%) in active practice. Eighty-two percent (n = 1,204) mentioned having used endoscopy in their practice, and 64.7% (n = 961/1486) received formal flexible endoscopy training. Of those performing endoscopy annually, 64.2% (n = 660/1486) performed between 0 and 20 endoscopies, 15.2% (n = 156/1486) performed between 20 and 50 endoscopies, 10.1% (n = 104/1486) performed between 50 and 100 endoscopies, and 10.5% (n = 108/1486) performed over 100 endoscopies. From the regression analysis, there was no statistical correlation between the annual endoscopy volume and age, geographic region, laparoscopic surgery practice, or surgical specialization. Performing advanced endoscopy was directly related to the bariatric subspecialty and to performing over 50% of cases in a minimally invasive fashion. CONCLUSIONS: This international snapshot audit revealed significant heterogeneity in endoscopic practices among surgeons worldwide. There was a nonindependent relationship between endoscopy volumes and other variables tested. Barriers to practicing and receiving endoscopy training were common among respondents. The EAES Flexible Endoscopy Subcommittee will consider such results when developing an equitable and effective standardized flexible endoscopy curriculum.

Objective Assessment of Cognitive Workload in Surgery: A Systematic Review.

OBJECTIVE: To systematically review technologies that objectively measure CWL in surgery, assessing their psychometric and methodological characteristics. SUMMARY BACKGROUND DATA: Surgical tasks involving concurrent clinical decision-making and the safe application of technical and non-technical skills require a substantial cognitive demand and resource utilization. Cognitive overload leads to impaired clinical decision-making and performance decline. Assessing cognitive workload (CWL) could enable interventions to alleviate burden and improve patient safety. METHODS: Ovid MEDLINE, OVID Embase, the Cochrane Library and IEEE Xplore databases were searched from inception to August 2023. Full-text, peer-reviewed original studies in a population of surgeons, anesthesiologists or interventional radiologists were considered, with no publication date constraints. Study population, task paradigm, stressor, Cognitive Load Theory (CLT) domain, objective and subjective parameters, statistical analysis and results were extracted. Studies were assessed for a) definition of CWL, b) details of the clinical task paradigm, and c) objective CWL assessment tool. Assessment tools were evaluated using psychometric and methodological characteristics. RESULTS: 10790 studies were identified; 9004 were screened; 269 full studies were assessed for eligibility, of which 67 met inclusion criteria. The most widely used assessment modalities were autonomic (32 eye studies and 24 cardiac). Intrinsic workload (e.g. task complexity) and germane workload (effect of training or expertize) were the most prevalent designs investigated. CWL was not defined in 30 of 67 studies (44.8%). Sensitivity was greatest for neurophysiological instruments (100% EEG, 80% fNIRS); and across modalities accuracy increased with multi-sensor recordings. Specificity was limited to cardiac and ocular metrics, and was found to be sub-optimal (50% and 66.67%). Cardiac sensors were the least intrusive, with 54.2% of studies conducted in naturalistic clinical environments (higher ecological validity). CONCLUSION: Physiological metrics provide an accessible, objective assessment of CWL, but dependence on autonomic function negates selectivity and diagnosticity. Neurophysiological measures demonstrate favorable sensitivity, directly measuring brain activation as a correlate of cognitive state. Lacking an objective gold standard at present, we recommend the concurrent use of multimodal objective sensors and subjective tools for cross-validation. A theoretical and technical framework for objective assessment of CWL is required to overcome the heterogeneity of methodological reporting, data processing, and analysis.

Eye-controlled endoscopy - a benchtop trial of a novel robotic steering platform - iGAZE2.

The endoscopic control system has remained similar in design for many decades The remit of advanced therapeutic endoscopy continues to expand requiring precision control and high cognitive workloads. Robotic systems are emerging, but all still require bimanual control and expensive and large new systems. Eye tracking is an exciting area that can be used as an endoscope control system. This is a study to establish the feasibility of an eye-controlled endoscope and compare its performance and cognitive demand to use of a conventional endoscope. An eye gaze-control system consisting of eye-tracking glasses, customised software and a small motor unit was built and attached to a conventional endoscope. Twelve non-endoscopists used both the eye gaze system and a conventional endoscope to complete a benchtop task in a simulated oesophagus and stomach. Completion of tasks was timed. Subjective feedback was collected from each participant on task load using the NASA Task Load Index. Participants were significantly quicker completing the task using iGAZE2 vs a conventional endoscope (65.02 ± 16.34s vs 104.21 ± 51.31s, p = 0.013) Participants were also significantly quicker completing retroflexion using iGAZE2 vs a conventional endoscope (8.48 ± 3.08 vs 11.38 ± 5.36s, p = 0.036). Participants reported a significantly lower workload (raw NASA-TLX score) when using iGAZE2 vs the conventional endoscope (152.1 ± 63.4 vs 319.6 ± 81.6, p = 0.0001) (Fig. 7). Users found iGAZE2 to have a significantly lower temporal demand, mental demand, effort, mental demand, physical demand, and frustration level. The eye gaze system is an exciting, small, and retrofittable system to any endoscope. The system shows exciting potential as a novel endoscopic control system with a significantly lower workload and better performance in novices suggesting a more intuitive control system.

A Tension Sensor Array for Cable-Driven Surgical Robots.

Tendon-sheath structures are commonly utilized to drive surgical robots due to their compact size, flexibility, and straightforward controllability. However, long-distance cable tension estimation poses a significant challenge due to its frictional characteristics affected by complicated factors. This paper proposes a miniature tension sensor array for an endoscopic cable-driven parallel robot, aiming to integrate sensors into the distal end of long and flexible surgical instruments to sense cable tension and alleviate friction between the tendon and sheath. The sensor array, mounted at the distal end of the robot, boasts the advantages of a small size (16 mm outer diameter) and reduced frictional impact. A force compensation strategy was presented and verified on a platform with a single cable and subsequently implemented on the robot. The robot demonstrated good performance in a series of palpation tests, exhibiting a 0.173 N average error in force estimation and a 0.213 N root-mean-square error. In blind tests, all ten participants were able to differentiate between silicone pads with varying hardness through force feedback provided by a haptic device.

Telestration with augmented reality improves surgical performance through gaze guidance.

BACKGROUND: In minimally invasive surgery (MIS), trainees need to learn how to interpret the operative field displayed on the laparoscopic screen. Experts currently guide trainees mainly verbally during laparoscopic procedures. A newly developed telestration system with augmented reality (iSurgeon) allows the instructor to display hand gestures in real-time on the laparoscopic screen in augmented reality to provide visual expert guidance (telestration). This study analysed the effect of telestration guided instructions on gaze behaviour during MIS training. METHODS: In a randomized-controlled crossover study, 40 MIS naive medical students performed 8 laparoscopic tasks with telestration or with verbal instructions only. Pupil Core eye-tracking glasses were used to capture the instructor's and trainees' gazes. Gaze behaviour measures for tasks 1-7 were gaze latency, gaze convergence and collaborative gaze convergence. Performance measures included the number of errors in tasks 1-7 and trainee's ratings in structured and standardized performance scores in task 8 (ex vivo porcine laparoscopic cholecystectomy). RESULTS: There was a significant improvement 1-7 on gaze latency [F(1,39) = 762.5, p < 0.01, ηp2 = 0.95], gaze convergence [F(1,39) = 482.8, p < 0.01, ηp2 = 0.93] and collaborative gaze convergence [F(1,39) = 408.4, p < 0.01, ηp2 = 0.91] upon instruction with iSurgeon. The number of errors was significantly lower in tasks 1-7 (0.18 ± 0.56 vs. 1.94 ± 1.80, p < 0.01) and the score ratings for laparoscopic cholecystectomy were significantly higher with telestration (global OSATS: 29 ± 2.5 vs. 25 ± 5.5, p < 0.01; task-specific OSATS: 60 ± 3 vs. 50 ± 6, p < 0.01). CONCLUSIONS: Telestration with augmented reality successfully improved surgical performance. The trainee's gaze behaviour was improved by reducing the time from instruction to fixation on targets and leading to a higher convergence of the instructor's and the trainee's gazes. Also, the convergence of trainee's gaze and target areas increased with telestration. This confirms augmented reality-based telestration works by means of gaze guidance in MIS and could be used to improve training outcomes.

Eye tracking technology in endoscopy: Looking to the future.

The visual patterns of an endoscopist, that is, what the endoscopist is looking at during luminal endoscopy, is an interesting area with an evolving evidence base. The tools required for gaze analysis have become cheaper and more easily accessible. A comprehensive literature search was undertaken identifying 19 relevant papers. Gaze analysis has been used to identify certain visual patterns associated with higher polyp detection rates. There have also been increasing applications of gaze analysis as an objective study tool to compare the effectiveness of endoscopic imaging technologies. Gaze analysis also has the potential to be incorporated into endoscopic training. Eye movements have been used to control and steer a robotic endoscope. This review presents the current evidence available in this novel and evolving field of endoscopic research.

The Measurement of Cognitive Workload in Surgery Using Pupil Metrics: A Systematic Review and Narrative Analysis.

INTRODUCTION: Increased cognitive workload (CWL) is a well-established entity that can impair surgical performance and increase the likelihood of surgical error. The use of pupil and gaze tracking data is increasingly being used to measure CWL objectively in surgery. The aim of this review is to summarize and synthesize the existing evidence that surrounds this. METHODS: A systematic review was undertaken in accordance with Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. A search of OVID MEDLINE, IEEE Xplore, Web of Science, Google Scholar, APA PsychINFO, and EMBASE was conducted for articles published in English between 1990 and January 2021. In total, 6791 articles were screened and 32 full-text articles were selected based on the inclusion criteria. A narrative analysis was undertaken in view of the heterogeneity of studies. RESULTS: Seventy-eight percent of selected studies were deemed high quality. The most frequent surgical environment and task studied was surgical simulation (75%) and performance of laparoscopic skills (56%) respectively. The results demonstrated that the current literature can be broadly categorized into pupil, blink, and gaze metrics used in the assessment of CWL. These can be further categorized according to their use in the context of CWL: (1) direct measurement of CWL (n = 16), (2) determination of expertise level (n = 14), and (3) predictors of performance (n = 2). CONCLUSIONS: Eye-tracking data provide a wealth of information; however, there is marked study heterogeneity. Pupil diameter and gaze entropy demonstrate promise in CWL assessment. Future work will entail the use of artificial intelligence in the form of deep learning and the use of a multisensor platform to accurately measure CWL.

An eye-tracking based robotic scrub nurse: proof of concept.

BACKGROUND: Within surgery, assistive robotic devices (ARD) have reported improved patient outcomes. ARD can offer the surgical team a "third hand" to perform wider tasks and more degrees of motion in comparison with conventional laparoscopy. We test an eye-tracking based robotic scrub nurse (RSN) in a simulated operating room based on a novel real-time framework for theatre-wide 3D gaze localization in a mobile fashion. METHODS: Surgeons performed segmental resection of pig colon and handsewn end-to-end anastomosis while wearing eye-tracking glasses (ETG) assisted by distributed RGB-D motion sensors. To select instruments, surgeons (ST) fixed their gaze on a screen, initiating the RSN to pick up and transfer the item. Comparison was made between the task with the assistance of a human scrub nurse (HSNt) versus the task with the assistance of robotic and human scrub nurse (R&HSNt). Task load (NASA-TLX), technology acceptance (Van der Laan's), metric data on performance and team communication were measured. RESULTS: Overall, 10 ST participated. NASA-TLX feedback for ST on HSNt vs R&HSNt usage revealed no significant difference in mental, physical or temporal demands and no change in task performance. ST reported significantly higher frustration score with R&HSNt. Van der Laan's scores showed positive usefulness and satisfaction scores in using the RSN. No significant difference in operating time was observed. CONCLUSIONS: We report initial findings of our eye-tracking based RSN. This enables mobile, unrestricted hands-free human-robot interaction intra-operatively. Importantly, this platform is deemed non-inferior to HSNt and accepted by ST and HSN test users.

A novel gaze-controlled flexible robotized endoscope; preliminary trial and report.

BACKGROUND: Interventional endoluminal therapy is rapidly advancing as a minimally invasive surgical technique. The expanding remit of endoscopic therapy necessitates precision control. Eye tracking is an emerging technology which allows intuitive control of devices. This was a feasibility study to establish if a novel eye gaze-controlled endoscopic system could be used to intuitively control an endoscope. METHODS: An eye gaze-control system consisting of eye tracking glasses, specialist cameras and a joystick was used to control a robotically driven endoscope allowing steering, advancement, withdrawal and retroflexion. Eight experienced and eight non-endoscopists used both the eye gaze system and a conventional endoscope to identify ten targets in two simulated environments: a sphere and an upper gastrointestinal (UGI) model. Completion of tasks was timed. Subjective feedback was collected from each participant on task load (NASA Task Load Index) and acceptance of technology (Van der Laan scale). RESULTS: When using gaze-control endoscopy, non-endoscopists were significantly quicker when using gaze-control rather than conventional endoscopy (sphere task 3:54 ± 1:17 vs. 9:05 ± 5:40 min, p = 0.012, and UGI model task 1:59 ± 0:24 vs 3:45 ± 0:53 min, p < .001). Non-endoscopists reported significantly higher NASA-TLX workload total scores using conventional endoscopy versus gaze-control (80.6 ± 11.3 vs 22.5 ± 13.8, p < .001). Endoscopists reported significantly higher total NASA-TLX workload scores using gaze control versus conventional endoscopy (54.2 ± 16 vs 26.9 ± 15.3, p = 0.012). All subjects reported that the gaze-control had positive 'usefulness' and 'satisfaction' score of 0.56 ± 0.83 and 1.43 ± 0.51 respectively. CONCLUSIONS: The novel eye gaze-control system was significantly quicker to use and subjectively lower in workload when used by non-endoscopists. Further work is needed to see if this would translate into a shallower learning curve to proficiency versus conventional endoscopy. The eye gaze-control system appears feasible as an intuitive endoscope control system. Hybrid gaze and hand control may prove a beneficial technology to evolving endoscopic platforms.

Tool-tissue forces in surgery: A systematic review.

BACKGROUND: Excessive tool-tissue interaction forces often result in tissue damage and intraoperative complications, while insufficient forces prevent the completion of the task. This review sought to explore the tool-tissue interaction forces exerted by instruments during surgery across different specialities, tissues, manoeuvres and experience levels. MATERIALS & METHODS: A PRISMA-guided systematic review was carried out using Embase, Medline and Web of Science databases. RESULTS: Of 462 articles screened, 45 studies discussing surgical tool-tissue forces were included. The studies were categorized into 9 different specialities with the mean of average forces lowest for ophthalmology (0.04N) and highest for orthopaedic surgery (210N). Nervous tissue required the least amount of force to manipulate (mean of average: 0.4N), whilst connective tissue (including bone) required the most (mean of average: 45.8). For manoeuvres, drilling recorded the highest forces (mean of average: 14N), whilst sharp dissection recorded the lowest (mean of average: 0.03N). When comparing differences in the mean of average forces between groups, novices exerted 22.7% more force than experts, and presence of a feedback mechanism (e.g. audio) reduced exerted forces by 47.9%. CONCLUSIONS: The measurement of tool-tissue forces is a novel but rapidly expanding field. The range of forces applied varies according to surgical speciality, tissue, manoeuvre, operator experience and feedback provided. Knowledge of the safe range of surgical forces will improve surgical safety whilst maintaining effectiveness. Measuring forces during surgery may provide an objective metric for training and assessment. Development of smart instruments, robotics and integrated feedback systems will facilitate this.

Haptic Intracorporeal Palpation Using a Cable-Driven Parallel Robot: A User Study.

OBJECTIVE: Intraoperative palpation is a surgical gesture jeopardized by the lack of haptic feedback which affects robotic minimally invasive surgery. Restoring the force reflection in teleoperated systems may improve both surgeons' performance and procedures' outcome. METHODS: A force-based sensing approach was developed, based on a cable-driven parallel manipulator with anticipated seamless and low-cost integration capabilities in teleoperated robotic surgery. No force sensor on the end-effector is used, but tissue probing forces are estimated from measured cable tensions. A user study involving surgical trainees (n = 22) was conducted to experimentally evaluate the platform in two palpation-based test-cases on silicone phantoms. Two modalities were compared: visual feedback alone and both visual + haptic feedbacks available at the master site. RESULTS: Surgical trainees' preference for the modality providing both visual and haptic feedback is corroborated by both quantitative and qualitative metrics. Hard nodules detection sensitivity improves (94.35 ± 9.1% vs 76.09 ± 19.15% for visual feedback alone), while also exerting smaller forces (4.13 ± 1.02 N vs 4.82 ± 0.81 N for visual feedback alone) on the phantom tissues. At the same time, the subjective perceived workload decreases. CONCLUSION: Tissue-probe contact forces are estimated in a low cost and unique way, without the need of force sensors on the end-effector. Haptics demonstrated an improvement in the tumor detection rate, a reduction of the probing forces, and a decrease in the perceived workload for the trainees. SIGNIFICANCE: Relevant benefits are demonstrated from the usage of combined cable-driven parallel manipulators and haptics during robotic minimally invasive procedures. The translation of robotic intraoperative palpation to clinical practice could improve the detection and dissection of cancer nodules.

Next-generation robotics in gastrointestinal surgery.

The global numbers of robotic gastrointestinal surgeries are increasing. However, the evidence base for robotic gastrointestinal surgery does not yet support its widespread adoption or justify its cost. The reasons for its continued popularity are complex, but a notable driver is the push for innovation - robotic surgery is seen as a compelling solution for delivering on the promise of minimally invasive precision surgery - and a changing commercial landscape delivers the promise of increased affordability. Novel systems will leverage the robot as a data-driven platform, integrating advances in imaging, artificial intelligence and machine learning for decision support. However, if this vision is to be realized, lessons must be heeded from current clinical trials and translational strategies, which have failed to demonstrate patient benefit. In this Perspective, we critically appraise current research to define the principles on which the next generation of gastrointestinal robotics trials should be based. We also discuss the emerging commercial landscape and define existing and new technologies.

Soft Robotics in Minimally Invasive Surgery.

Soft robotic devices have desirable traits for applications in minimally invasive surgery (MIS), but many interdisciplinary challenges remain unsolved. To understand current technologies, we carried out a keyword search using the Web of Science and Scopus databases, applied inclusion and exclusion criteria, and compared several characteristics of the soft robotic devices for MIS in the resulting articles. There was low diversity in the device designs and a wide-ranging level of detail regarding their capabilities. We propose a standardized comparison methodology to characterize soft robotics for various MIS applications, which will aid designers producing the next generation of devices.

Deployable, Variable Stiffness, Cable Driven Robot for Minimally Invasive Surgery.

Minimally Invasive Surgery (MIS) imposes a trade-off between non-invasive access and surgical capability. Treatment of early gastric cancers over 20 mm in diameter can be achieved by performing Endoscopic Submucosal Dissection (ESD) with a flexible endoscope; however, this procedure is technically challenging, suffers from extended operation times and requires extensive training. To facilitate the ESD procedure, we have created a deployable cable driven robot that increases the surgical capabilities of the flexible endoscope while attempting to minimize the impact on the access that they offer. Using a low-profile inflatable support structure in the shape of a hollow hexagonal prism, our robot can fold around the flexible endoscope and, when the target site has been reached, achieve a 73.16% increase in volume and increase its radial stiffness. A sheath around the variable stiffness structure delivers a series of force transmission cables that connect to two independent tubular end-effectors through which standard flexible endoscopic instruments can pass and be anchored. Using a simple control scheme based on the length of each cable, the pose of the two instruments can be controlled by haptic controllers in each hand of the user. The forces exerted by a single instrument were measured, and a maximum magnitude of 8.29 N observed along a single axis. The working channels and tip control of the flexible endoscope remain in use in conjunction with our robot and were used during a procedure imitating the demands of ESD was successfully carried out by a novice user. Not only does this robot facilitate difficult surgical techniques, but it can be easily customized and rapidly produced at low cost due to a programmatic design approach.

A cable-driven parallel manipulator with force sensing capabilities for high-accuracy tissue endomicroscopy.

PURPOSE: Endomicroscopy (EM) provides high resolution, non-invasive histological tissue information and can be used for scanning of large areas of tissue to assess cancerous and pre-cancerous lesions and their margins. However, current robotic solutions do not provide the accuracy and force sensitivity required to perform safe and accurate tissue scanning. METHODS: A new surgical instrument has been developed that uses a cable-driven parallel mechanism (CPDM) to manipulate an EM probe. End-effector forces are determined by measuring the tensions in each cable. As a result, the instrument allows to accurately apply a contact force on a tissue, while at the same time offering high resolution and highly repeatable probe movement. RESULTS: 0.2 and 0.6 N force sensitivities were found for 1 and 2 DoF image acquisition methods, respectively. A back-stepping technique can be used when a higher force sensitivity is required for the acquisition of high quality tissue images. This method was successful in acquiring images on ex vivo liver tissue. CONCLUSION: The proposed approach offers high force sensitivity and precise control, which is essential for robotic EM. The technical benefits of the current system can also be used for other surgical robotic applications, including safe autonomous control, haptic feedback and palpation.

Gaze-contingent perceptually enabled interactions in the operating theatre.

PURPOSE: Improved surgical outcome and patient safety in the operating theatre are constant challenges. We hypothesise that a framework that collects and utilises information -especially perceptually enabled ones-from multiple sources, could help to meet the above goals. This paper presents some core functionalities of a wider low-cost framework under development that allows perceptually enabled interaction within the surgical environment. METHODS: The synergy of wearable eye-tracking and advanced computer vision methodologies, such as SLAM, is exploited. As a demonstration of one of the framework's possible functionalities, an articulated collaborative robotic arm and laser pointer is integrated and the set-up is used to project the surgeon's fixation point in 3D space. RESULTS: The implementation is evaluated over 60 fixations on predefined targets, with distances between the subject and the targets of 92-212 cm and between the robot and the targets of 42-193 cm. The median overall system error is currently 3.98 cm. Its real-time potential is also highlighted. CONCLUSIONS: The work presented here represents an introduction and preliminary experimental validation of core functionalities of a larger framework under development. The proposed framework is geared towards a safer and more efficient surgical theatre.

The impact of expert visual guidance on trainee visual search strategy, visual attention and motor skills.

Minimally invasive and robotic surgery changes the capacity for surgical mentors to guide their trainees with the control customary to open surgery. This neuroergonomic study aims to assess a "Collaborative Gaze Channel" (CGC); which detects trainer gaze-behavior and displays the point of regard to the trainee. A randomized crossover study was conducted in which twenty subjects performed a simulated robotic surgical task necessitating collaboration either with verbal (control condition) or visual guidance with CGC (study condition). Trainee occipito-parietal (O-P) cortical function was assessed with optical topography (OT) and gaze-behavior was evaluated using video-oculography. Performance during gaze-assistance was significantly superior [biopsy number: (mean ± SD): control = 5.6 ± 1.8 vs. CGC = 6.6 ± 2.0; p < 0.05] and was associated with significantly lower O-P cortical activity [ΔHbO2 mMol × cm [median (IQR)] control = 2.5 (12.0) vs. CGC 0.63 (11.2), p < 0.001]. A random effect model (REM) confirmed the association between guidance mode and O-P excitation. Network cost and global efficiency were not significantly influenced by guidance mode. A gaze channel enhances performance, modulates visual search, and alleviates the burden in brain centers subserving visual attention and does not induce changes in the trainee's O-P functional network observable with the current OT technique. The results imply that through visual guidance, attentional resources may be liberated, potentially improving the capability of trainees to attend to other safety critical events during the procedure.