Enhancing robotic telesurgery with sensorless haptic feedback

PURPOSE

This paper evaluates user performance in telesurgical tasks with the da Vinci Research Kit (dVRK), comparing unilateral teleoperation, bilateral teleoperation with force sensors and sensorless force estimation.

METHODS

A four-channel teleoperation system with disturbance observers and sensorless force estimation with learning-based dynamic compensation was developed. Palpation experiments were conducted with 12 users who tried to locate tumors hidden in tissue phantoms with their fingers or through handheld or teleoperated laparoscopic instruments with visual, force sensor, or sensorless force estimation feedback. In a peg transfer experiment with 10 users, the contribution of sensorless haptic feedback with/without learning-based dynamic compensation was assessed using NASA TLX surveys, measured free motion speeds and forces, environment interaction forces as well as experiment completion times.

RESULTS

The first study showed a 30% increase in accuracy in detecting tumors with sensorless haptic feedback over visual feedback with only a 5-10% drop in accuracy when compared with sensor feedback or direct instrument contact. The second study showed that sensorless feedback can help reduce interaction forces due to incidental contacts by about 3 times compared with unilateral teleoperation. The cost is an increase in free motion forces and physical effort. We show that it is possible to improve this with dynamic compensation.

CONCLUSION

We demonstrate the benefits of sensorless haptic feedback in teleoperated surgery systems, especially with dynamic compensation, and that it can improve surgical performance without hardware modifications.

DefCor-Net: Physics-aware ultrasound deformation correction

The recovery of morphologically accurate anatomical images from deformed ones is challenging in ultrasound (US) image acquisition, but crucial to accurate and consistent diagnosis, particularly in the emerging field of computer-assisted diagnosis. This article presents a novel physics-aware deformation correction approach based on a coarse-to-fine, multi-scale deep neural network (DefCor-Net). To achieve pixel-wise performance, DefCor-Net incorporates biomedical knowledge by estimating pixel-wise stiffness online using a U-shaped feature extractor. The deformation field is then computed using polynomial regression by integrating the measured force applied by the US probe. Based on real-time estimation of pixel-by-pixel tissue properties, the learning-based approach enables the potential for anatomy-aware deformation correction. To demonstrate the effectiveness of the proposed DefCor-Net, images recorded at multiple locations on forearms and upper arms of six volunteers are used to train and validate DefCor-Net. The results demonstrate that DefCor-Net can significantly improve the accuracy of deformation correction to recover the original geometry (Dice Coefficient: from 14.3±20.9 to 82.6±12.1 when the force is 6N). Code:https://github.com/KarolineZhy/DefCorNet.

Comparative Effectiveness of Various Radiofrequency Ablation Catheters in the Ablation of Typical Atrial Flutter

INTRODUCTION

Although ablation of typical atrial flutter (AFL) can be easily achieved with radiofrequency energy (RF), no studies compare the effectiveness of different ablation catheters. Our study aimed to compare the efficacy of various types of ablation catheters in treating typical AFL.

METHODS

We analyzed patients with AFL who underwent RF ablation by a single operator at our institution. Successful ablation was evidenced by a bidirectional conduction block (trans-isthmus conduction time ≥ 130 ms or double potentials ≥ 90 ms). Logistic regression was used to compare success rate and linear regression to compare lesion time.

RESULTS

Out of 222 patients, only six did not meet the success criteria (2.7%). The catheters used were non-irrigated, large-tip, internally irrigated (Chili II Boston Scientific), and externally irrigated (non-force-sensing) catheters (Cool Path, Abbott). An externally irrigated force-sensing catheter (TactiCath, Abbott) was used with > 10 gm of force and (LPLD) setting (30 W- 45 °C- 60 s), and high-power short-duration (HPSD) setting (50 W- 43 °C - 12 s). No complications were encountered. The catheter type had no statistically significant association with ablation success. With the use of externally irrigated catheter with contract force-sensing and HPSD settings, statistically significantly shortening of lesion time was achieved 758.3 s, [CI - 1128.29, - 388.35 s] followed by LPLD by 419.0 s [CI - 808.49, - 29.47 s].

CONCLUSIONS

The typical atrial flutter radiofrequency ablation procedure had a high success rate, which was not influenced by the type of ablation catheter. Contact force ablation catheter and HPSD are associated with shorter total lesion time.

A force-sensing surgical drill for real-time force feedback in robotic mastoidectomy

PURPOSE

Robotic assistance in otologic surgery can reduce the task load of operating surgeons during the removal of bone around the critical structures in the lateral skull base. However, safe deployment into the anatomical passageways necessitates the development of advanced sensing capabilities to actively limit the interaction forces between the surgical tools and critical anatomy.

METHODS

We introduce a surgical drill equipped with a force sensor that is capable of measuring accurate tool-tissue interaction forces to enable force control and feedback to surgeons. The design, calibration and validation of the force-sensing surgical drill mounted on a cooperatively controlled surgical robot are described in this work.

RESULTS

The force measurements on the tip of the surgical drill are validated with raw-egg drilling experiments, where a force sensor mounted below the egg serves as ground truth. The average root mean square error for points and path drilling experiments is 41.7 (± 12.2) mN and 48.3 (± 13.7) mN, respectively.

CONCLUSION

The force-sensing prototype measures forces with sub-millinewton resolution and the results demonstrate that the calibrated force-sensing drill generates accurate force measurements with minimal error compared to the measured drill forces. The development of such sensing capabilities is crucial for the safe use of robotic systems in a clinical context.

Miniature Flexible Instrument with Fibre Bragg Grating-Based Triaxial Force Sensing for Intraoperative Gastric Endomicroscopy

Optical biopsy methods, such as probe-based endomicroscopy, can be used to identify early-stage gastric cancer in vivo. However, it is difficult to scan a large area of the gastric mucosa for mosaicking during endoscopy. In this work, we propose a miniaturised flexible instrument based on contact-aided compliant mechanisms and fibre Bragg grating (FBG) sensing for intraoperative gastric endomicroscopy. The instrument has a compact design with an outer diameter of 2.7 mm, incorporating a central channel with a diameter of 1.9 mm for the endomicroscopic probe to pass through. Experimental results show that the instrument can achieve raster trajectory scanning over a large tissue surface with a positioning accuracy of 0.5 mm. The tip force sensor provides a 4.6 mN resolution for the axial force and 2.8 mN for transverse forces. Validation with random samples shows that the force sensor can provide consistent and accurate three-axis force detection. Endomicroscopic imaging experiments were conducted, and the flexible instrument performed no gap scanning (mosaicking area more than 3 mm²) and contact force monitoring during scanning, demonstrating the potential of the system in clinical applications.

A uniaxial force and stiffness model of the vagina during laparoscopic sacrocolpopexy

BACKGROUND

Laparoscopic sacrocolpopexy is the preferred procedure for restoring vaginal vault prolapse. An assistant uses a vaginal manipulator to position and tension the vault such that the surgeon can dissect the bladder, rectum and vault to eventually suture a synthetic mesh used to suspend the vagina to the longitudinal anterior vertebral ligament. Vaginal vault manipulation requires application of high forces for long periods of time.

METHODS

This work quantifies the task by measuring and analyzing the interaction forces and the workspace during vaginal vault manipulation. From the measurements we developed a uniaxial model, expressing the increase in interaction force and stiffness of the vagina. By adapting the model parameters, the difference in interaction force and stiffness between moderate and severe prolapse is predicted.

FINDINGS

For moderate prolapse the average interaction force and stiffness start at 2.56 N and 0.11 N mm^-1 in the tensionfree state, and go up to 20.14 N and 0.53 N mm^-1 after complete insertion of the instrument. For severe degrees of prolapse, tissue interaction is much lower starting at 1.68 N and 0.06 N mm^-1 while staying limited to 12.20 N and 0.30 N mm^-1 at full extension.

INTERPRETATION

Population data shows that the stage of prolapse and total vaginal length increase with age and parity. The interaction force and stiffness of the vagina are correlated with this degree of prolapse. By adapting the model parameters a good estimation of the tissue interaction is found for patients with mild and severe prolapse.

The Structure of Acto-Myosin

After several decades studying different acto-myosin complexes at lower and intermediate resolution - limited by the electron microscope instrumentation available then - recent advances in imaging technology have been crucial for obtaining a number of excellent high-resolution 3D reconstructions from cryo electron microscopy. The resolution level reached now is about 3-4 Å, which allows unambiguous model building of filamentous actin on its own as well as that of actin filaments decorated with strongly bound myosin variants. The interface between actin and the myosin motor domain can now be described in detail, and the function of parts of the interface (such as, e.g., the cardiomyopathy loop) can be understood in a mechanistical way. Most recently, reconstructions of actin filaments decorated with different myosins, which show a strongly bound acto-myosin complex also in the presence of the nucleotide ADP, have become available. The comparison of these structures with the nucleotide-free Rigor state provide the first mechanistic description of force sensing. An open question is still the initial interaction of the motor domain of myosin with the actin filament. Such weakly interacting states have so far not been the subject of microscopical studies, even though high-resolution structures would be needed to shed light on the initial steps of phosphate release and power stroke initiation.

Innovative Force-PRO device to measure force and implant position in total hip arthroplasty

Total hip arthroplasty (THA) is the appropriate treatment for hip pain, dislocation, and dysfunction. THA refers to surgery to replace a hip implant, which is an effective way to recover normal hip function. The design of an implant imitates hip functions and allows bone growth in the implant area. However, it should be noted that the implant can dislocate after surgery. The main factor that should be considered during surgery is the correct position of the implant component. The acetabular cup of the hip implant should be positioned at [Formula: see text] anteversion and [Formula: see text] inclination. The evaluation of the implant inclination and anteversion during the operation decrease the risk of the implant dislocation after surgery. Developing a new innovative Force-PRO device can aid the doctor in evaluating the force on the surface of the acetabular liner and the angle of the acetabular liner during the hip implant operation. This device consists of two main sensors-force sensors and inertial measurement unit sensors. Furthermore, the 3D printings of an implant's parts should be specifically designed to integrate with these sensors. To develop the graphical user interface application, C[Formula: see text] should be the programming language of use. The graphical user interface application communicates between the device and user via a wireless communication system. CT-based imaging and force gauge measurement are the methods to evaluate the efficiency of this device. For this purpose, the sterile method is considered.

Haptic Feedback, Force Feedback, and Force-Sensing in Simulation Training for Laparoscopy: A Systematic Overview

OBJECTIVES

To provide a systematic overview of the literature assessing the value of haptic and force feedback in current simulators teaching laparoscopic surgical skills.

DATA SOURCES

The databases of Pubmed, Cochrane, Embase, Web of Science, and Google Scholar were searched to retrieve relevant studies published until January 31st, 2017. The search included laparoscopic surgery, simulation, and haptic or force feedback and all relevant synonyms.

METHODS

Duplicates were removed, and titles and abstracts screened. The remaining articles were subsequently screened full text and included in this review if they followed the inclusion criteria. A total of 2 types of feedback have been analyzed and will be discussed separately: haptic- and force feedback.

RESULTS

A total of 4023 articles were found, of which 87 could be used in this review. A descriptive analysis of the data is provided. Results of the added value of haptic interface devices in virtual reality are variable. Haptic feedback is most important for more complex tasks. The interface devices do not require the highest level of fidelity. Haptic feedback leads to a shorter learning curve with a steadier upward trend. Concerning force feedback, force parameters are measured through force sensing systems in the instrument and/or the environment. These parameters, especially in combination with motion parameters, provide box trainers with an objective evaluation of laparoscopic skills. Feedback of force-use both real time and postpractice has been shown to improve training.

CONCLUSIONS

Haptic feedback is added to virtual reality simulators to increase the fidelity and thereby improve training effect. Variable results have been found from adding haptic feedback. It is most important for more complex tasks, but results in only minor improvements for novice surgeons. Force parameters and force feedback in box trainers have been shown to improve training results.

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.

Robotic Scanning Device for Intraoperative Thyroid Gland Endomicroscopy

Probe-based confocal laser endomicroscopy has a high potential to be a promising tool that can provide intraoperative high-resolution in vivo morphological imaging at cellular and subcellular levels for thyroidectomy, and allow real-time assessment of tumor margins. However, the typical images acquired with this technique cover a very small area limited by the field of view of the probe, accompanied by tissue deformation and inconsistent probe-tissue contact when operated manually. In this paper, a novel compact robotic device for large area scanning has been developed. The device can scan a large surface in a spiral trajectory by rotating the tip frame along the spiral groove of the base frame. The fiber Bragg grating sensor with a passive linear structure is used to detect and maintain a stable probe-tissue contact force during scanning. An active linear actuation is also integrated for adjusting the probe-tissue contact level prior to each scan. Results demonstrate that the scanning device ensures a suitable probe-tissue contact force and compensates for simulated hand tremor. Mosaicing results of lens tissue paper and porcine belly tissue with both bench and hand-held experiments show the effectiveness and usability of the device, demonstrating the potential clinical value of the system.

Objective Assessment of Endovascular Navigation Skills with Force Sensing

Despite the increasing popularity of endovascular intervention in clinical practice, there remains a lack of objective and quantitative metrics for skill evaluation of endovascular techniques. Data relating to the forces exerted during endovascular procedures and the behavioral patterns of endovascular clinicians is currently limited. This research proposes two platforms for measuring tool forces applied by operators and contact forces resulting from catheter-tissue interactions, as a means of providing accurate, objective metrics of operator skill within a realistic simulation environment. Operator manipulation patterns are compared across different experience levels performing various complex catheterization tasks, and different performance metrics relating to tool forces, catheter motion dynamics, and forces exerted on the vasculature are extracted. The results depict significant differences between the two experience groups in their force and motion patterns across different phases of the procedures, with support vector machine (SVM) classification showing cross-validation accuracies as high as 90% between the two skill levels. This is the first robust study, validated across a large pool of endovascular specialists, to present objective measures of endovascular skill based on exerted forces. The study also provides significant insights into the design of optimized metrics for improved training and performance assessment of catheterization tasks.