Konrad Leibrandt

Evaluation of a novel flexible snake robot for endoluminal surgery

BackgroundEndoluminal therapeutic procedures such as endoscopic submucosal dissection are increasingly attractive given the shift in surgical paradigm towards minimally invasive surgery. This novel three-channel articulated robot was developed to overcome the limitations of the flexible endoscope which poses a number of challenges to endoluminal surgery. The device enables enhanced movement in a restricted workspace, with improved range of motion and with the accuracy required for endoluminal surgery.ObjectiveTo evaluate a novel flexible robot for therapeutic endoluminal surgery.DesignBench-top studies.SettingResearch laboratory.InterventionTargeting and navigation tasks of the robot were performed to explore the range of motion and retroflexion capabilities. Complex endoluminal tasks such as endoscopic mucosal resection were also simulated.Main outcome measurementsSuccessful completion, accuracy and time to perform the bench-top tasks were the main outcome measures.ResultsThe robot ranges of movement, retroflexion and navigation capabilities were demonstrated. The device showed significantly greater accuracy of targeting in a retroflexed position compared to a conventional endoscope.LimitationsBench-top study and small study sample.ConclusionsWe were able to demonstrate a number of simulated endoscopy tasks such as navigation, targeting, snaring and retroflexion. The improved accuracy of targeting whilst in a difficult configuration is extremely promising and may facilitate endoluminal surgery which has been notoriously challenging with a conventional endoscope.

Making the Leap: the Translation of Innovative Surgical Devices From the Laboratory to the Operating Room

Objective:To determine the rate and extent of translation of innovative surgical devices from the laboratory to first-in-human studies, and to evaluate the factors influencing such translation. Summary Background Data:Innovative surgical devices have preceded many of the major advances in surgical practice. However, the process by which devices arising from academia find their way to translation remains poorly understood. Methods:All biomedical engineering journals, and the 5 basic science journals with the highest impact factor, were searched between January 1993 and January 2000 using the Boolean search term “surgery OR surgeon OR surgical”. Articles were included if they described the development of a new device and a surgical application was described. A recursive search of all citations to the article was performed using the Web of Science (Thompson-Reuters, New York, NY) to identify any associated first-in-human studies published by January 2015. Kaplan-Meier curves were constructed for the time to first-in-human studies. Factors influencing translation were evaluated using log-rank and Cox proportional hazards models. Results:A total of 8297 articles were screened, and 205 publications describing unique devices were identified. The probability of a first-in-human at 10 years was 9.8%. Clinical involvement was a significant predictor of a first-in-human study (P = 0.02); devices developed with early clinical collaboration were over 6 times more likely to be translated than those without [RR 6.5 (95% confidence interval 0.9–48)]. Conclusions:These findings support initiatives to increase clinical translation through improved interactions between basic, translational, and clinical researchers.

On-line collision-free inverse kinematics with frictional active constraints for effective control of unstable concentric tube robots

Concentric tube robots are catheter-sized robots that are ideally suited for navigating along natural anatomical pathways and treating deep-seated pathologies. Their telemanipulation in dynamic environments requires on-line computation of inverse kinematics with simultaneous avoidance of anatomical obstacles. Moreover, unstable configurations, which arise for elongated curved robots that navigate extremely tortuous paths, must be avoided. To achieve on-line computations, existing work has investigated Jacobian approximations and configuration-space precomputation. This paper leverages the state-of-the-art multi-core computer architectures to deliver real-time local inverse kinematics solutions using the established concentric tube robot mechanics models while avoiding both instabilities and anatomical collisions. Furthermore, it considers frictional active constraints for concentric tube robots, i.e. viscoelastic force fields that guide the operator away from obstacles and towards safe configurations. The value of the proposed framework is demonstrated on realistic clinical scenarios.

Implicit active constraints for a compliant surgical manipulator

Active constraints are high-level control algorithms providing software-generated force feedback from virtual environments. When applied to surgery, they can assist surgeons in performing complex tasks by guiding their navigation pathways along narrow, possibly convoluted, surgical trajectories. This paper presents a method to generate concave tubular constraints implicitly from pre- or intra-operative data. Patient-specific constraints may be generated efficiently with the proposed scheme and readily deployed in various surgical scenarios. Furthermore, a five degree-of-freedom active constraint framework is proposed, which accounts for the entire tool shaft rather than just the end-effector, and is applicable to both static and dynamic active constraint scenarios. Experimental results on simulated surgical tasks show that this framework can improve safety and accuracy as well as reduce the perceived workload during complex surgical tasks.

Vision-based deformation recovery for intraoperative force estimation of tool–tissue interaction for neurosurgery

PurposeIn microsurgery, accurate recovery of the deformation of the surgical environment is important for mitigating the risk of inadvertent tissue damage and avoiding instrument maneuvers that may cause injury. The analysis of intraoperative microscopic data can allow the estimation of tissue deformation and provide to the surgeon useful feedback on the instrument forces exerted on the tissue. In practice, vision-based recovery of tissue deformation during tool–tissue interaction can be challenging due to tissue elasticity and unpredictable motion.MethodsThe aim of this work is to propose an approach for deformation recovery based on quasi-dense 3D stereo reconstruction. The proposed framework incorporates a new stereo correspondence method for estimating the underlying 3D structure. Probabilistic tracking and surface mapping are used to estimate 3D point correspondences across time and recover localized tissue deformations in the surgical site.ResultsWe demonstrate the application of this method to estimating forces exerted on tissue surfaces. A clinically relevant experimental setup was used to validate the proposed framework on phantom data. The quantitative and qualitative performance evaluation results show that the proposed 3D stereo reconstruction and deformation recovery methods achieve submillimeter accuracy. The force–displacement model also provides accurate estimates of the exerted forces.ConclusionsA novel approach for tissue deformation recovery has been proposed based on reliable quasi-dense stereo correspondences. The proposed framework does not rely on additional equipment, allowing seamless integration with the existing surgical workflow. The performance evaluation analysis shows the potential clinical value of the technique.

Effective Manipulation in Confined Spaces of Highly Articulated Robotic Instruments for Single Access Surgery

The field of robotic surgery increasingly advances towards highly articulated and continuum robots, requiring new kinematic strategies to enable users to perform dexterous manipulation in confined workspaces. This development is driven by surgical interventions accessing the surgical workspace through natural orifices such as the mouth or the anus. Due to the long and narrow nature of these access pathways, external triangulation at the fulcrum point is very limited or absent, which makes introducing multiple degrees of freedom at the distal end of the instrument necessary. Additionally, high force and miniaturization requirements make the control of such instruments particularly challenging. This letter presents the kinematic considerations needed to effectively manipulate these novel instruments and allow us their dexterous control in confined spaces. A nonlinear calibration model is further used to map joint to actuator space and improve significantly the precision of the instruments motion. The effectiveness of the presented approach is quantified with bench tests, and the usability of the system is assessed by three user studies simulating the requirements of a realistic surgical task.

Implicit active constraints for safe and effective guidance of unstable concentric tube robots

Safe and effective telemanipulation of concentric tube robots is hindered by their complex, non-intuitive kinematics. Guidance schemes in the form of attractive and repulsive constraints can simplify task execution and facilitate natural operation of the robot by clinicians. The real-time seamless calculation and application of guidance, however, requires computationally efficient algorithms that solve the non-linear inverse kinematics of the robot and guarantee that the commanded robot configuration is stable and sufficiently away from the anatomy. This paper presents a multi-processor framework that allows on-the-fly calculation of optimal safe paths based on rapid workspace and roadmap pre-computation The real-time nature of the developed software enables complex guidance constraints to be implemented with minimal computational overhead. A user study on a simulated challenging clinical problem demonstrated that the incorporated guiding constraints are highly beneficial for fast and accurate navigation with concentric tube robots.

Design and evaluation of a novel flexible robot for transluminal and endoluminal surgery

Precise and repetitive positional control of surgical robots is important to reduce time and risks of surgical procedures. These factors become particularly important when deploying the surgical system through a flexible path to areas with a tight workspace such as the stomach or oesophagus where high dexterity, flexibility, accuracy and stability are required. This paper presents a flexible access robot combining articulated joints and continuum flexible section for both transluminal and endoluminal surgeries. Kinematic model and control strategy for the flexible robot are described in the paper. The experiment simulating a transoral gastric procedure demonstrates great flexibility and dexterity of the device. The results show that good accuracy and repetitive control of the device are achieved, which demonstrate the potential application of the device for transluminal or endoluminal surgery.

A Single-Port Robotic System for Transanal Microsurgery—Design and Validation

This letter introduces a single-port robotic platform for transanal endoscopic microsurgery (TEMS). Two robotically controlled articulated surgical instruments are inserted via a transanal approach to perform submucosal or full-thickness dissection. This system is intended to replace the conventional TEMS approach that uses manual laparoscopic instruments. The new system is based on master–slave robotically controlled tele-manipulation. The slave robot comprises a support arm that is mounted on the operating table, supporting a surgical port and a robotic platform that drives the surgical instruments. The master console includes a pair of haptic devices, as well as a three-dimensional display showing the live video stream of a stereo endoscope inserted through the surgical port. The surgical instrumentation consists of energy delivery devices, graspers, and needle drivers allowing a full TEMS procedure to be performed. Results from benchtop tests, ex vivo animal tissue evaluation, and in vivo studies demonstrate the clinical advantage of the proposed system.

Concentric Tube Robots: Rapid, Stable Path-Planning and Guidance for Surgical Use

The complex, nonintuitive kinematics of concentric tube robots (CTRs) can make their telemanipulation challenging. Collaborative control schemes that guide the operating clinician via repulsive and attractive force feedback based on intraoperative path planning can simplify this task. Computationally efficient algorithms, however, are required to perform rapid path planning and solve the inverse kinematics of the robot at interactive rates. Until now, ensuring stable and collisionfree robot configurations required long periods of precomputation to establish kinematic look-up tables. This article presents a high-performance robot kinematics software architecture, which is used together with a multinode computational framework to rapidly calculate dense path plans for safe telemanipulation of unstable CTRs. The proposed software architecture enables on-the-fly, incremental, inverse-kinematics estimation at interactive rates, and it is tailored to modern computing architectures with efficient multicore central processing units (CPUs). The effectiveness of the architecture is quantified with computational-complexity metrics and a clinically demanding simulation inspired from neurosurgery for hydrocephalus treatment. By achieving real-time path planning, active constraints (ACs) can get generated on the fly and support the operator in faster and more reliable execution of telemanipulation tasks.