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Increased demand for less invasive procedures has accelerated the adoption of Intraluminal Procedures (IP) and Endovascular Interventions (EI) performed through body lumens and vessels. As navigation through lumens and vessels is quite complex, interest grows to establish autonomous navigation techniques for IP and EI for reaching the target area. Current research efforts are directed toward increasing the Level of Autonomy (LoA) during the navigation phase. One key ingredient for autonomous navigation is Motion Planning (MP) techniques. This paper provides an overview of MP techniques categorizing them based on LoA. Our analysis investigates advances for the different clinical scenarios. Through a systematic literature analysis using the PRISMA method, the study summarizes relevant works and investigates the clinical aim, LoA, adopted MP techniques, and validation types. We identify the limitations of the corresponding MP methods and provide directions to improve the robustness of the algorithms in dynamic intraluminal environments. MP for IP and EI can be classified into four subgroups: node, sampling, optimization, and learning-based techniques, with a notable rise in learning-based approaches in recent years. One of the review's contributions is the identification of the limiting factors in IP and EI robotic systems hindering higher levels of autonomous navigation. In the future, navigation is bound to become more autonomous, placing the clinician in a supervisory position to improve control precision and reduce workload., 31 pages, 7 figures, 3 tables; Accepted in IEEE Transactions on Robotics

PURPOSE: Robot-assisted ultrasound (rUS) systems have already been used to provide non-radiative three-dimensional (3D) reconstructions that form the basis for guiding spine surgical procedures. Despite promising studies on this technology, there are few studies that offer insight into the robustness and generality of the approach by verifying performance in various testing scenarios. Therefore, this study aims at providing an assessment of a rUS system, with technical details from experiments starting at the bench-top to the pre-clinical study. METHODS: A semi-automatic control strategy was proposed to ensure continuous and smooth robotic scanning. Next, a U-Net-based segmentation approach was developed to automatically process the anatomic features and derive a high-quality 3D US reconstruction. Experiments were conducted on synthetic phantoms and human cadavers to validate the proposed approach. RESULTS: Average deviations of scanning force were found to be 2.84±0.45 N on synthetic phantoms and to be 5.64±1.10 N on human cadavers. The anatomic features could be reliably reconstructed at mean accuracy of 1.28±0.87 mm for the synthetic phantoms and of 1.74±0.89 mm for the human cadavers. CONCLUSION: The results and experiments demonstrate the feasibility of the proposed system in a pre-clinical setting. This work is complementary to previous work, encouraging further exploration of the potential of this technology in in vivo studies. ispartof: INTERNATIONAL JOURNAL OF COMPUTER ASSISTED RADIOLOGY AND SURGERY ispartof: location:Germany status: Published online

PurposeFetoscopic laser coagulation for twin-to-twin transfusion syndrome is challenging for anterior placenta due to the rigidity of current tools. The capacity to keep entry port forces minimal is critical for this procedure, as is optimal coagulation distance and orientation. This work introduces technological tools to this end.MethodsA novel fetoscope is presented with a rigid shaft and a flexible steerable segment at the distal end. The steerable segment can bend up to 90∘even when loaded with a laser fiber. An artificial pneumatic muscle makes such acute bending possible while allowing for a low-weight and disposable device.ResultsThe flexible fetoscope was validated in a custom-made phantom model to measure visual range and coagulation efficacy. The flexible fetoscope shows promising results when compared to a clinical rigid curved fetoscope to reach anterior targets. The new fetoscope was then evaluated in vivo (pregnant ewe) where it successfully coagulated placental vasculature.ConclusionThe flexible fetoscope improved the ability to achieve optimal coagulation angle and distance on anteriorly located targets. The fetoscope also showed the potential to lead fetoscopic laser coagulation and other fetal surgical procedures toward safer and more effective interventions.

ispartof: ADVANCED FUNCTIONAL MATERIALS vol:33 issue:15 status: published

Purpose: Robot-assisted ultrasound (US) systems could be used to provide a non-radiative three-dimensional (3D) reconstruction that can form the basis for guiding spine surgical procedures. Despite promising studies on this technology, there are few studies that offer insight into the robustness and generality of the approach by e.g. verifying performance in various testing scenarios. Therefore, this study provides an assessment of the robot-assisted US system, with technical details from experiments starting at the bench-top up to the pre-clinical study. Methods: A semi-automatic control strategy is proposed to ensure continuous and smooth scanning. Next, a method based on U-Net was developed to automatically process the anatomic features and derive a high quality 3D US reconstruction. Experiments on phantoms and human cadavers validate the proposed approach. Results: Average deviations of scanning force were found of 2.84 ± 0.45 N on synthetic phantoms and of 5.64 ± 1.10 N on human cadavers. The reconstruction yielded a mean 3D representation error of 1.28 ± 0.87 mm for the synthetic phantoms and of 1.74 ± 0.89 mm for the human cadavers. Conclusion: These results show the proposed system has high safety performance and could keep the probe force stable within the range of 1 N to obtain a good reconstruction. The experiments indicate that the proposed robotassisted US approach works in quite different experimental settings. The results encourage to also explore the potential of this technology in in-vivo studies.

Intra-operative local 3D vessel representations have the potential to significantly decrease the use of contrast agents and exposure to ionizing radiation during endovascular procedures, while overcoming the 2D visualization limitation of fluoroscopic guidance. By fusing intravascular ultrasound (IVUS) imaging and electromagnetic (EM) pose sensing in a robotic catheter tip, a real-time local 3D model of the vasculature could be constructed intra-operatively. This letter proposes the use of a cylinder model to approximate the vessel geometry near the catheter tip. An unscented Kalman filter is employed to robustly estimate the cylinder that best fits IVUS and EM data while navigating through the vessel. This forms a radiation-free alternative to conventional radiation-based guidance. Validation on one in silico and two in vitro models showed median estimation errors of cylinder radius of 0.14 mm, 0.42 mm and 0.70 mm; cylinder position of 0.45 mm, 1.07 mm and 0.96 mm; and cylinder orientation of $2.94^\circ$ , $4.60^\circ$ and $3.03^\circ$ showing great potential for helping interventionists preventing harmful interactions between the instrument tip and the vessel wall.

Force sensing is highly desirable in minimally invasive medical applications, since this feature shows great potential for reducing tissue damage and enhancing manipulation safety. However, embedding force sensors in medical devices is challenging and costly. This article explores the possibility to use shape sensing as a measure to extract force information. In this work, a model-based approach that allows simultaneous shape and force sensing is proposed. Shape information is reconstructed employing a multicore fiber with fiber Bragg grating sensors spaced over the fiber length. This fiber is capable of distributed 3D shape sensing. It is shown how by making use of extended Kalman filter and a mechanics model of the flexible instrument, it becomes possible to estimate both the magnitudes and locations of externally applied forces. Experiments were carried out to validate the proposed method for both one and two external forces applied at arbitrary locations in different directions on a flexible instrument. Results show that one-directional force magnitude and location can be estimated with an average error of 23.08 mN (15.39%) and 11.06 mm (6.51%), respectively. For two-directional forces, results of the load near the base show an average error of 52.01 mN (30.59%) for the magnitude and 29.24 mm (17.20%) for the location. For the load applied simultaneously near the tip, the mean magnitude error is 16.79 mN (11.19%) and the average location error is 10.18 mm (5.99%). The force sensing algorithm can run in real time with an approximate frequency of 59 Hz. In these experiments, it can be observed that the force-sensing accuracy, which depends on the sensitivity of the shape of flexible instruments with respect to the external force, can vary drastically in function of the force application point and force direction.

Patch-clamp is a widely used technique to record the electrophysiological activity of neurons in vivo. However, establishing and maintaining a long-term stable recording is difficult due to neuronal motion induced by physiological motion. This abstract proposes an Extended Kalman Filter (EKF) method for motion estimation based on Electrical Bioimpedance (EBI) sensing. The results show that with EBI, the EKF could estimate the motion with high precision (RMSE = 0.022V) and robustness (STD = 0.0028V) in real-time.

Autostereoscopic 3D visualization (ASV) forms a potentially appealing alternative to stereoscopic 3D displays to help surgeons regain depth perception during minimally invasive surgery (MIS). However, the feasibility of using single-viewer ASV has not yet been demonstrated in a clinical context. The purpose of the study is to analyze the current surgical workflow and display usage and assess the potential for using ASV in MIS applications. Additionally, the study seeks to acquire a better understanding of key design requirements, such as the eye-tracking performance and the lenticular lens 3D workspace.Two types of gynecologic interventions were investigated. A vision-based tracking system was developed, consisting of depth cameras mounted on the displays and ArUco markers placed on the hair caps of clinicians and the wall of the operating room. This allowed simultaneous tracking of the pose of operating staff and displays.Overall 20 surgeries were recorded, where 4 clinicians operated using 3 displays. Users were typically standing at a mean distance of 1900 mm in a range from to 1200 to 2300 mm from the display. Left-right motion was from - 600 to 658 mm. Clinicians stood on average 1000 mm from each other. The head roll angle was below 16[Formula: see text].Surgeons were looking predominantly (99%) to the same display. Observations took place from fairly well-defined places and with sufficient potential to differentiate between clinicians, suggesting that single-viewer ASV would be feasible.

Development of high-performance flexible surgical instruments is important to simplify and enable new minimally invasive surgical procedures. New actuation technologies are necessary to produce flexible instrumentation that is capable of accessing difficult-to-reach anatomy and performing laborious tasks without damaging delicate tissues. Recently, concentric McKibben muscles and dual-chamber pneumatic artificial muscles (PAMs) have been proposed for use in miniature flexible robotic surgical instrumentation. In this study, several varieties of a hybrid concentric dual-chamber PAM design are built and their force generation and stroke length are compared to a contractile McKibben muscle. The concentric dual-chamber PAM is designed to provide surgical access for large diameter (1.5–2.0 mm) instruments to be delivered to the surgical site in a pneumatically sealed actuator suitable for miniaturization and integration into surgical devices used in fluid environments (fetal applications in particular). Force output of the concentric dual-chamber PAM is modeled and compared to experimental results. Initial results suggest that the newly introduced design produces a higher actuation force per unit length than traditional McKibben muscles. The prototype dual-channel PAM produced a maximum 15.25 N of force and 8.39 mm of stroke, in comparison to 13.31 N of force and 19.3 mm of stroke produced by a traditional contractile McKibben muscle of the same length, outer diameter, and materials. ispartof: Journal of Medical Robotics Research vol:7 issue:2 status: published

Hysteroscopy is a type of gynecological procedure that enables diagnosis and treatment of intrauterine pathologies using a minimally-invasive approach. Recent advancements, especially in optics, made it possible to perform this procedure in an ambulatory, outpatient setting without anaesthesia. Yet, such approach introduces additional challenges to gynecologists, as the surgical instruments have to pass through the cervix, a narrow curved canal. This process can be traumatic and even cause tissue damage or rupture. Current training curricula mainly focus on general minimally-invasive surgical skills or on inpatient hysteroscopy. This paper describes the first virtual reality training system designed purposely for in-office hysteroscopy training featuring both passive and active haptic feedback. Design requirements were defined through a literature review and a survey of clinical experts. A dedicated platform was developed and tested with clinicians and medical students. The results of the conducted experiments verified the skill acquisition capabilities of the platform showing a.o. shorter execution time and path length, lower integral forces in most of non-expert participants. The results also demonstrated the capability of the system to differentiate between experts and non-expert groups. Reported findings suggest that the platform has the potential to evolve into an effective solution for in-office hysteroscopy training. ispartof: IEEE Transactions on Medical Robotics and Bionics vol:4 issue:3 status: Published online

The emergence of steerable flexible instruments has widened the uptake of minimally invasive surgical techniques. In sinus surgery, such flexible instruments could enable the access to difficult-to-reach anatomical areas. However, design-oriented metrics, essential for the development of steerable flexible instruments for maxillary sinus surgery, are still lacking. This paper proposes a method to process measurements and provides the instrument designer with essential information to develop adapted flexible instruments for limited access surgery. This method was applied to maxillary sinus surgery and showed that an instrument with a diameter smaller than 2.4 mm can be used on more than 72.5% of the subjects’ set. Based on the statistical analysis and provided that this flexible instrument can bend up to $$164.4^\circ,$$ it is estimated that all areas within the maxillary sinus could be reached through a regular antrostomy without resorting to extra incision or tissue removal in 94.9% of the population set. The presented method was partially validated by conducting cadaver experiments.

Purpose Fetoscopic laser photocoagulation is a minimally invasive surgery for the treatment of twin-to-twin transfusion syndrome (TTTS). By using a lens/fibre-optic scope, inserted into the amniotic cavity, the abnormal placental vascular anastomoses are identified and ablated to regulate blood flow to both fetuses. Limited field-of-view, occlusions due to fetus presence and low visibility make it difficult to identify all vascular anastomoses. Automatic computer-assisted techniques may provide better understanding of the anatomical structure during surgery for risk-free laser photocoagulation and may facilitate in improving mosaics from fetoscopic videos. Methods We propose FetNet, a combined convolutional neural network (CNN) and long short-term memory (LSTM) recurrent neural network architecture for the spatio-temporal identification of fetoscopic events. We adapt an existing CNN architecture for spatial feature extraction and integrated it with the LSTM network for end-to-end spatio-temporal inference. We introduce differential learning rates during the model training to effectively utilising the pre-trained CNN weights. This may support computer-assisted interventions (CAI) during fetoscopic laser photocoagulation. Results We perform quantitative evaluation of our method using 7 in vivo fetoscopic videos captured from different human TTTS cases. The total duration of these videos was 5551 s (138,780 frames). To test the robustness of the proposed approach, we perform 7-fold cross-validation where each video is treated as a hold-out or test set and training is performed using the remaining videos. Conclusion FetNet achieved superior performance compared to the existing CNN-based methods and provided improved inference because of the spatio-temporal information modelling. Online testing of FetNet, using a Tesla V100-DGXS-32GB GPU, achieved a frame rate of 114 fps. These results show that our method could potentially provide a real-time solution for CAI and automating occlusion and photocoagulation identification during fetoscopic procedures.

In this article, a deep learning method for the shape sensing of continuum robots based on multicore fiber bragg grating (FBG) fiber is introduced. The proposed method, based on an artificial neural network (ANN), differs from traditional approaches, where accurate shape reconstruction requires a tedious characterization of many characteristic parameters. A further limitation of traditional approaches is that they require either multiple fibers, whose location relative to the centerline must be precisely known (calibrated), or a single multicore fiber whose position typically coincides with the neutral line. The proposed method addresses this limitation and, thus, allows shape sensing based on a single multicore fiber placed off-center. This helps in miniaturizing and leaves the central channel available for other purposes. The proposed approach was compared to a recent state-of-the-art model-based shape sensing approach. A two-degree-of-freedom benchtop fluidics-driven catheter system was built to validate the proposed ANN. The proposed ANN-based shape sensing approach was evaluated on a 40-mm-long steerable continuum robot in both 3-D free-space and 2-D constrained environments, yielding an average shape sensing error of 0.24 and 0.49 mm, respectively. With these results, the superiority of the proposed approach compared to the recent model-based shape sensing method was demonstrated.

Precise control of robotic catheters remains challenging in interventions. Inherent non-linearities such as hysteresis and external disturbances such as blood flow or contact with the vessel walls have a large impact on the reachable positioning precision. As inaccurate positioning of the catheter tip could lead to tissue damage, controllers that would perform adequately in the presence of hysteresis and environmental contacts would be highly desirable. This paper proposes a method based on multiple Long Short-Term Memory Networks (LSTMs). To this end, a so-called free-space-LSTM (f-LSTM) is trained in order to steer the catheter when it moves in free. Constrained-space-LSTMs (c-LSTMs) are trained to drive the catheter when it is in contact with an obstacle. Based on contact estimation methods, LSTMs are switched. The f-LSTM and c-LSTMs are first tested in free space motion and under constraint situations. The results reveal that LSTMs perform well (RMSE < 0.5 mm) for a steerable robot section with a total length of 77 mm when tested in the same situation where trained. However, when f-LSTM and c-LSTM were tested in an environment different from the one in which they were trained, errors tended to increase. The results highlight the need to exhaustively estimate the contact location and switch between different LSTMs accordingly. The effective working range of a c-LSTM was investigated as well. Experiments showed that a well-Trained single c-LSTM could be used effectively in a range of 8.8 mm among the entire length of a steerable catheter section, while maintaining the average tip positioning error below 2 mm in this range.

Continuum robots such as robotic catheters are increasingly being used in minimally invasive surgery. Compliance contributes to enhanced safety during e.g. catheter insertion, however, estimation of contact force and location may help clinicians avoiding exerting excessive force. Ultimately this could lead to faster and safer interventions. Researchers proposed force sensors integrated in the catheter tip in the past. However, such sensors add extra complexity to the catheter design. Also, tip force sensors do not provide insights on forces that act along the catheter length. This paper proposes a data-driven approach for localizing contact forces that appear over the length of the catheter. The proposed approach consists of a collision detection method and a contact localization method. The framework only requires the measurement of the catheter's shape which can be done by an embedded multi-core Fiber Bragg Grating fiber. The method was validated experimentally with a 3D-printed continuum robot with an integrated multi-core fiber. A second contact localization method which is based on identifying the discontinuity in the measured curvature, is also implemented and compared with the proposed method. The static and dynamic experiments show a mean average localization error of 2.3 mm and 4.3 mm which correspond to respectively 3.3% and 6.1% of a 70 mm long flexible robot. These findings demonstrate that the proposed framework outperforms the previous methods and yield promising results. The contact state estimation algorithm can detect collisions in at most approximately 1.08s.

This work presents an RL-based agent for outpatient hysteroscopy training. Hysteroscopy is a gynecological procedure for examination of the uterine cavity. Recent advancements enabled performing this type of intervention in the outpatient setup without anaesthesia. While being beneficial to the patient, this approach introduces new challenges for clinicians, who should take additional measures to maintain the level of patient comfort and prevent tissue damage. Our prior work has presented a platform for hysteroscopic training with the focus on the passage of the cervical canal. With this work, we aim to extend the functionality of the platform by designing a subsystem that autonomously performs the task of the passage of the cervical canal. This feature can later be used as a virtual instructor to provide educational cues for trainees and assess their performance. The developed algorithm is based on the soft actor critic approach to smooth the learning curve of the agent and ensure uniform exploration of the workspace. The designed algorithm was tested against the performance of five clinicians. Overall, the algorithm demonstrated high efficiency and reliability, succeeding in 98% of trials and outperforming the expert group in three out of four measured metrics.

The shoulder complex is known as the highest degrees-of-freedom (DoFs) mechanism in the human body. It consists of the clavicle, scapula, and thorax allowing the human arm to perform a large range of motion. However, in the case of robotic systems, the shoulder complex is often kinematically simplified or substituted with a serial-chain mechanism due to the complexity of the musculoskeletal systems. As a matter of fact, the human shoulder makes use of the scapula movement to extend its range of motion. The pneumatic artificial muscles (PAMs) have been evaluated as the most similar actuators to the human muscles. When pressurized air is applied, PAMs swell and contract. PAMs are faster and more lightweight than other actuators because the power source is air. Also, PAMs are appealing as small-sized air compressors are becoming available. This paper presents a robotic shoulder complex actuated by PAMs. The PAMs are arranged in such a way as to mimic the musculoskeletal system of the shoulder complex. In order to allow a lightweight implementation of the robotic shoulder complex, ball joints and a deformable membrane are chosen instead of mechanical bearings. The effectiveness of the proposed mechanism was validated through simulation and experiments. ispartof: pages:70-76 ispartof: 2022 19TH INTERNATIONAL CONFERENCE ON UBIQUITOUS ROBOTS (UR) pages:70-76 ispartof: 19th International Conference on Ubiquitous Robots (UR) location:SOUTH KOREA, Jeju date:4 Jul - 6 Jul 2022 status: published

ispartof: pages:1-7 ispartof: 2021 International Symposium on Medical Robotics (ISMR) pages:1-7 ispartof: 2021 International Symposium on Medical Robotics (ISMR) location:Georgia Tech, Atlanta, USA date:17 Nov - 19 Nov 2021 status: Published online

ispartof: pages:1-5 ispartof: 2021 International Symposium on Medical Robotics (ISMR) pages:1-5 ispartof: International Symposium on Medical Robotics location:Atlanta, Georgia, USA date:17 Nov - 19 Nov 2021 status: published

INTRODUCTION: Monopolar electrocautery is the most common dissection and coagulation tool during transoral robotic surgery (TORS) but causes significant collateral tissue damage as opposed to CO2 laser. We aimed at combining both modalities in one robotic instrument arm. METHODS: We developed a steerable CO2 -laser fibre carrier serving as an add-on to the existing Endowrist® monopolar spatula of the Da Vinci Xi. Feasibility and safety were assessed in a preclinical setting. RESULTS: One radical tonsillectomy with monopolar cautery and three with the instrument prototype were performed in two cadavers by two surgeons. No serious prototype-related intra-operative difficulties were observed. Safe and efficient switching between energy sources proved possible in all simulated intra-operative bleeding events. Prototype use allowed for the identification of the majority of key anatomical structures and was scored favourably on NASA-TLX questionnaires. DISCUSSION: The reported prototype successfully combines the advantages of CO2 -laser with the advantages of TORS. ispartof: INTERNATIONAL JOURNAL OF MEDICAL ROBOTICS AND COMPUTER ASSISTED SURGERY vol:18 issue:1 ispartof: location:England status: published

Monopolar electrocautery is the most common dissection and coagulation tool during transoral robotic surgery (TORS) but causes significant collateral tissue damage as opposed to COWe developed a steerable COOne radical tonsillectomy with monopolar cautery and three with the instrument prototype were performed in two cadavers by two surgeons. No serious prototype-related intra-operative difficulties were observed. Safe and efficient switching between energy sources proved possible in all simulated intra-operative bleeding events. Prototype use allowed for the identification of the majority of key anatomical structures and was scored favourably on NASA-TLX questionnaires.The reported prototype successfully combines the advantages of CO

The use of McKibben pneumatic artificial muscles in surgical instruments is increasing due to their light weight, miniaturization potential, compliance and large actuation force. However, precise position and force control is still challenging due to the intrinsic muscle hysteresis. The present work proposes an easy-to-make integrated capacitance sensor for miniature artificial muscles by replacing two strands of the muscle braid with two conductive wires. By measuring the capacitance at high excitation frequency between both wires, the length of the muscle can be deduced. This new integrated sensor still allows the miniaturization of McKibben muscles. The miniature muscle with integrated capacitance sensing only loses 3% of its contraction length with regard to an original McKibben muscle. The sensor can predict the muscle length with a 0.31mm precision over 80% of the muscle total achievable contraction range in average.

Many keyhole interventions rely on bi-manual handling of surgical instruments, forcing the main surgeon to rely on a second surgeon to act as a camera assistant. In addition to the burden of excessively involving surgical staff, this may lead to reduced image stability, increased task completion time and sometimes errors due to the monotony of the task. Robotic endoscope holders, controlled by a set of basic instructions, have been proposed as an alternative, but their unnatural handling may increase the cognitive load of the (solo) surgeon, which hinders their clinical acceptance. More seamless integration in the surgical workflow would be achieved if robotic endoscope holders collaborated with the operating surgeon via semantically rich instructions that closely resemble instructions that would otherwise be issued to a human camera assistant, such as "focus on my right-hand instrument". As a proof of concept, this paper presents a novel system that paves the way towards a synergistic interaction between surgeons and robotic endoscope holders. The proposed platform allows the surgeon to perform a bimanual coordination and navigation task, while a robotic arm autonomously performs the endoscope positioning tasks. Within our system, we propose a novel tooltip localization method based on surgical tool segmentation and a novel visual servoing approach that ensures smooth and appropriate motion of the endoscope camera. We validate our vision pipeline and run a user study of this system. The clinical relevance of the study is ensured through the use of a laparoscopic exercise validated by the European Academy of Gynaecological Surgery which involves bi-manual coordination and navigation. Successful application of our proposed system provides a promising starting point towards broader clinical adoption of robotic endoscope holders., Caspar Gruijthuijsen and Luis C. Garcia-Peraza-Herrera have contributed equally to this work and share first authorship

The twin-to-twin transfusion syndrome is a severe fetal anomaly appearing in up to 15% of identical twin pregnancies. This anomaly occurs when twins share blood vessels from a common placenta. The complication leads to an unbalanced blood transfusion between both fetuses. A current surgical treatment consists in coagulating the shared vessels using a fetoscope with an embedded laser. Such treatment is very delicate and constraining due to limited vision and size of the insertion area. The rigidity and lack of controllability of the current used instruments add an additional difficulty and limit the choice in insertion site. This letter proposes an improved flexible fetoscope, offering an enhanced laser controllability and higher versatility regarding the location of the insertion site. A better approach angle can therefore be realized. Also, tissue damage may be further reduced. This single-handed controllable active fetoscope is obtained after adaptation of a LithoVue (Boston Scientific, Natick, MA, USA), a commercially available passive flexible ureteroscope. The LithoVue is fitted with a unique lightweight add-on actuation module foreseen of an artificial muscle and a dedicated control system. Experiments in a mixed reality trainer suggested that the proposed fetoscope is compact, ergonomic, and intuitive in use, allowing an adequate control of the flexible end.

Endovascular catheterization is an intervention which offers a low risk alternative to open surgery in many patients. Today’s interventions rely heavily on fluoroscopic imaging to guide interventionalists. Fluoroscopy only produces 2D visualization of the catheter and also exposes both the patient and interventionalists to harmful radiation. Different approaches have been proposed to overcome the limitations of fluoroscopy. Fiber Bragg Grating (FBG)-based shape sensing is becoming popular to reconstruct the catheter shape. Multi-core fibers with parallel optical cores are interesting as they allow 3D shape reconstruction with a single fiber. A common issue with FBG-based shape sensing is its sensitivity to variations in twist. Even small amounts of twist can significantly impact the overall shape reconstruction accuracy. This work proposes a novel approach which combines electromagnetic tracking (EMT), FBG-based shape sensing, and sparse fluoroscopic images. The method provides real-time 3D visualization of the catheter without the need of continuous fluoroscopy. A unique feature of the proposed method is the selective use of imaging for dynamic twist-compensation of the FBG sensor. The proposed sensor-fusion method improved 3D reconstruction accuracy. Real-world in-vitro experiments promising results. For a catheter with an embedded fiber length of 170 mm, the proposed approach the 3D shape with a median root-mean-square (rms) error of 0.39 mm and an interquartile range of 0.10 mm in the 2D experiment in which the catheter was bent in a plane. A median rms error of 0.54 mm and an interquartile range of 0.07 mm were achieved in the 3D experiments. ispartof: Ieee Sensors Journal vol:21 issue:20 pages:1-12 status: Published online

Surface exploration in virtual reality has a large potential to enrich the user’s experience. It could for example be used to train and simulate medical palpation. During palpation, users tap, indent, and rub the surface of a sample to estimate the underlying properties. However, up to now there is no good approach to render such intricate interaction realistically. This paper introduces 6 degrees of freedom (DoF) encountered-type haptic display technology for simulating surface exploration tasks. Among the different phases of exploration, this article focuses on the ‘in-contact sliding’ phase. Two novel control approaches to render sliding over a virtual surface are elaborated. A first rendering method generates lateral frictional forces as the finger slides over the surface. A second method adjusts the inclination of the end-effector to render tissue properties. With both methods a stiff nodule embedded in a soft tissue was prepared. User experiments were carried out to find proper parameter and intensity ranges and to confirm the feasibility of the new rendering schemes. Participants indicated that both rendering schemes felt realistic. Compared to earlier work, where only the vertical stiffness was altered, lower thresholds to detect and localise embedded virtual nodules were found. Users also made fewer errors in detecting nodule edges. Furthermore, the method that used end-effector inclination allowed faster discovery of the nodule’s edges. It is expected that approaches that combine both rendering methods could provide an even more realistic feel.

Side-notched tube structures made of superelastic material are increasingly being studied in surgical robotics as they can easily be integrated into surgical instruments and offer the surgeon enhanced dexterity. Their simple design and ability to achieve large bending angles and small bending radii make them particularly suited for use in constrained workspace surgery. Up to now, however, no model has been able to accurately predict the behavior of such types of structures for large bending angles. This study, therefore, proposes a novel approach to model large displacements of side-notched tubes taking into account the superelasticity of the material, the non-constant curvature of the side-notched structure, as well as the friction induced by the actuating wire. More specifically, an equivalent, strain dependent, linear elastic modulus is used to model the superelastic behavior of the instrument’s material. The deformation of each separate section of the side-notched tube is calculated successively to capture the non-constant curvature of the NiTi backbone. The capstan equation is used to model cable friction. The model was tested on four samples of 2.3 mm diameter and was able to predict the bending angle of the side-notched tubes with a root mean square error (RMSE) of as low as () and the position of each notch with an RMSE of as low as 0.33 mm () across its entire bending range ( to ). The model was demonstrated for both tension and relaxation of the actuating wire. ispartof: International Journal Of Mechanical Sciences vol:197 status: Published online