Medical Robotic System Research Articles

Design, implementation and evaluation of an independent real-time safety layer for medical robotic systems using a force–torque–acceleration (FTA) sensor

Most medical robotic systems require direct interaction or contact with the robot. Force-Torque (FT) sensors can easily be mounted to the robot to control the contact pressure. However, evaluation is often done in software, which leads to latencies. To overcome that, we developed an independent safety system, named FTA sensor, which is based on an FT sensor and an accelerometer. An embedded system (ES) runs a real-time monitoring system for continuously checking of the readings. In case of a collision or error, it instantaneously stops the robot via the robot's external emergency stop. We found that the ES implementing the FTA sensor has a maximum latency of [Formula: see text] ms to trigger the robot's emergency stop. For the standard settings in the application of robotized transcranial magnetic stimulation, the robot will stop after at most 4 mm. Therefore, it works as an independent safety layer preventing patient and/or operator from serious harm.

Calibration of force/torque and acceleration for an independent safety layer in medical robotic systems

Background: Most medical robotic systems require direct interaction with the robot. Force-Torque (FT) sensors can easily be mounted to the robot. However, an accurate FT control requires the current robot position to compute the spatial orientation of the sensor for gravity compensation. Methods: We developed an independent safety system, named FTA sensor, which is based on an FT sensor and an accelerometer. With a calibration of accelerations to the FT coordinate frame, the current spatial orientation of the sensor is computed. Results: We found that the calibration of accelerations into the FT coordinate frame can be performed with a median rotational error of 3.5°. The median error for gravity compensation based on accelerations was 0.3N and 0.04Nm for forces and torques, respectively. Conclusion: By combining accelerations with force-torque readings, the FTA sensor works independently from robot input. Furthermore, the accuracy of the FTA sensor is sufficient for the purpose of medical robotic systems.

Single-site access robot-assisted epicardial mapping with a snake robot: preparation and first clinical experience

CardioARM, a highly flexible “snakelike” medical robotic system (Medrobotics, Raynham, MA), has been developed to allow physicians to view, access, and perform complex procedures intrapericardially on the beating heart through a single-access port. Transthoracic epicardial catheter mapping and ablation has emerged as a strategy to treat arrhythmias, particularly ventricular arrhythmias, originating from the epicardial surface. The aim of our investigation was to determine whether the CardioARM could be used to diagnose and treat ventricular tachycardia (VT) of epicardial origin. Animal and clinical studies of the CardioARM flexible robot were performed in hybrid surgical–electrophysiology settings. In a porcine model study, single-port pericardial access, navigation, mapping, and ablation were performed in nine animals. The device was then used in a small, single-center feasibility clinical study. Three patients, all with drug-refractory VT and multiple failed endocardial ablation attempts, underwent epicardial mapping with the flexible robot. In all nine animals, navigation, mapping, and ablation were successful without hemodynamic compromise. In the human study, all three patients demonstrated a favorable safety profile, with no major adverse events through a 30-day follow-up. Two cases achieved technical success, in which an electroanatomic map of the epicardial ventricle surface was created; in the third case, blood obscured visualization. These results, although based on a limited number of experimental animals and patients, show promise and suggest that further clinical investigation on the use of the flexible robot in patients requiring epicardial mapping of VT is warranted.Electronic supplementary materialThe online version of this article (doi:10.1007/s11701-012-0343-6) contains supplementary material, which is available to authorized users.

Medical Robots: Current Systems and Research Directions

First used medically in 1985, robots now make an impact in laparoscopy, neurosurgery, orthopedic surgery, emergency response, and various other medical disciplines. This paper provides a review of medical robot history and surveys the capabilities of current medical robot systems, primarily focusing on commercially available systems while covering a few prominent research projects. By examining robotic systems across time and disciplines, trends are discernible that imply future capabilities of medical robots, for example, increased usage of intraoperative images, improved robot arm design, and haptic feedback to guide the surgeon.

Skin-like pressure and strain sensors based on transparent elastic films of carbon nanotubes

Transparent, elastic conductors are essential components of electronic and optoelectronic devices that facilitate human interaction and biofeedback, such as interactive electronics, implantable medical devices and robotic systems with human-like sensing capabilities. The availability of conducting thin films with these properties could lead to the development of skin-like sensors that stretch reversibly, sense pressure (not just touch), bend into hairpin turns, integrate with collapsible, stretchable and mechanically robust displays and solar cells, and also wrap around non-planar and biological surfaces such as skin and organs, without wrinkling. We report transparent, conducting spray-deposited films of single-walled carbon nanotubes that can be rendered stretchable by applying strain along each axis, and then releasing this strain. This process produces spring-like structures in the nanotubes that accommodate strains of up to 150% and demonstrate conductivities as high as 2,200Scm(-1) in the stretched state. We also use the nanotube films as electrodes in arrays of transparent, stretchable capacitors, which behave as pressure and strain sensors.

Development of a medical robot system for minimally invasive surgery

Robot-assisted systems have been widely used in minimally invasive surgery (MIS) practice, and with them the precision and accuracy of surgical procedures can be significantly improved. Promoting the development of robot technology in MIS will improve robot performance and help in tackling problems from complex surgical procedures. A medical robot system with a new mechanism for MIS was proposed to achieve a two-dimensional (2D) remote centre of motion (RCM). An improved surgical instrument was designed to enhance manipulability and eliminate the coupling motion between the wrist and the grippers. The control subsystem adopted a master-slave control mode, upon which a new method with error compensation of repetitive feedback can be based for the inverse kinematics solution. A unique solution with less computation and higher satisfactory accuracy was also obtained. Tremor filtration and trajectory planning were also addressed with regard to the smoothness of the surgical instrument movement. The robot system was tested on pigs weighing 30-45 kg. The experimental results show that the robot can successfully complete a cholecystectomy and meet the demands of MIS. The results of the animal experiments were excellent, indicating a promising clinical application of the robot with high manipulability.

Robotic invasion of operation theatre and associated anaesthetic issues: A review

A Robotic device is a powered, computer controlled manipulator with artificial sensing that can be reprogrammed to move and position tools to carry out a wide range of tasks. Robots and Telemanipulators were first developed by the National Aeronautics and Space Administration (NASA) for use in space exploration. Today’s medical robotic systems were the brainchild of the United States Department of Defence’s desire to decrease war casualties with the development of ‘telerobotic surgery’. The ‘master-slave’ telemanipulator concept was developed for medical use in the early 1990s where the surgeon’s (master) manual movements were transmitted to end-effector (slave) instruments at a remote site. Since then, the field of surgical robotics has undergone massive transformation and the future is even brighter. As expected, any new technique brings with it risks and the possibility of technical difficulties. The person who bears the brunt of complications or benefit from a new invention is the ‘Patient’. Anaesthesiologists as always must do their part to be the patient’s ‘best man’ in the perioperative period. We should be prepared for screening and selection of patients in a different perspective keeping in mind the steep learning curves of surgeons, long surgical hours, extreme patient positioning and other previously unknown anaesthetic challenges brought about by the surgical robot. In this article we have tried to track the development of surgical robots and consider the unique anaesthetic issues related to robot assisted surgeries.

2P1-B03 画像処理を用いた医療用ロボットシステムの研究開発(医療ロボティクス・メカトロニクス)

2P1-B03 画像処理を用いた医療用ロボットシステムの研究開発(医療ロボティクス・メカトロニクス)

Design of the needle-driven robot for radio frequency ablation therapy based on ultrasound navigation

The ultrasonic image guided radio frequency ablation surgery is an effective technique in liver tumour treatment. However, the traditional surgery imposes a constraint for surgeons to have high precision in their hand?eye coordination. This paper discusses the design of an assisted medical robot system to reduce these requirements; the needle-driven robot system consists of needle-driven robot, 3D model navigation and a magnetic tracker. In the pre-operative phase, 3D model of the liver tumour is reconstructed and the needle insertion path is planed. In the intra-operative phase, the surgeon matches the pre-operative 3D model of the liver with real patient?s liver. Then, the needle-driven robot moves accurately at the target point where the surgeon inserts the needle into the liver tumour to destroy the tumour with microwave coagulation. A small and compact medical robot is proposed based on workspace optimisation in this paper. Experimental results show that the needle-driven robot location errors are less than 0.2 mm, whereas the robot ultrasound navigation system errors are less than 2.5 mm.

Remote minimally invasive surgery --haptic feedback and selective automation in medical robotics

The automation of recurrent tasks and force feedback are complex problems in medical robotics. We present a novel approach that extends human-machine skill-transfer by a scaffolding framework. It assumes a consolidated working environment for both, the trainee and the trainer. The trainer provides hints and cues in a basic structure which is already understood by the learner. In this work, the scaffolding is constituted by abstract patterns, which facilitate the structuring and segmentation of information during “Learning by Demonstration” LbD. With this concept, the concrete example of knot-tying for suturing is exemplified and evaluated. During the evaluation, most problems and failures arose due to intrinsic system imprecisions of the medical robot system. These inaccuracies were then improved by the visual guidance of the surgical instruments. While the benefits of force feedback in telesurgery has already been demonstrated and measured forces are also used during task learning, the transmission of signals between the operator console and the robot system over long-distances or across-network remote connections is still a challenge due to time-delay. Especially during incision processes with a scalpel into tissue, a delayed force feedback yields to an unpredictable force perception at the operator-side and can harm the tissue which the robot is interacting with. We propose a XFEM-based incision force prediction algorithm that simulates the incision contact-forces in real-time and compensates the delayed force sensor readings. A realistic 4-arm system for minimally invasive robotic heart surgery is used as a platform for the research.

Remote Minimally Invasive Surgery – Haptic Feedback and Selective Automation in Medical Robotics

The automation of recurrent tasks and force feedback are complex problems in medical robotics. We present a novel approach that extends human-machine skill-transfer by a scaffolding framework. It assumes a consolidated working environment for both, the trainee and the trainer. The trainer provides hints and cues in a basic structure which is already understood by the learner. In this work, the scaffolding is constituted by abstract patterns, which facilitate the structuring and segmentation of information during “Learning by Demonstration” (LbD). With this concept, the concrete example of knot-tying for suturing is exemplified and evaluated. During the evaluation, most problems and failures arose due to intrinsic system imprecisions of the medical robot system. These inaccuracies were then improved by the visual guidance of the surgical instruments. While the benefits of force feedback in telesurgery has already been demonstrated and measured forces are also used during task learning, the transmission of signals between the operator console and the robot system over long-distances or across-network remote connections is still a challenge due to time-delay. Especially during incision processes with a scalpel into tissue, a delayed force feedback yields to an unpredictable force perception at the operator-side and can harm the tissue which the robot is interacting with. We propose a XFEM-based incision force prediction algorithm that simulates the incision contact-forces in real-time and compensates the delayed force sensor readings. A realistic 4-arm system for minimally invasive robotic heart surgery is used as a platform for the research.

Evaluation of Low-Level Controllers for an Orthopedic Surgery Robotic System

In this paper, a computed-torque control and disturbance-observer-based control were evaluated for an orthopedic surgery robotic system called OrthoRoby, to track bone-cutting trajectory. Robust motion control is required to control a medical robotic system in an environment where model uncertainty and disturbances exist. Experiments were performed to demonstrate the performance of the tracking of the desired cutting trajectory when a computed-torque controller and disturbance-observer-based controller were used for OrthoRoby. It was observed that a computed-torque controller can become unstable with inexact cancellation due to parameter uncertainties and unmodeled dynamics. A disturbance-observer-based control was shown to ensure stability with inexact cancellation due to parameter uncertainties and unmodeled dynamics.

A Hybrid Control Approach for Non-invasive Medical Robotic Systems

In this paper, a hybrid supervisory control approach adopted for a non-invasive medical robot called Focused Ultrasound Surgical Robot--Breast Surgery (FUSBOT-BS) is elaborated. The system was built for the use in the breast surgery with high intensity focused ultrasound (HIFU) as the means of the treatment. A number of different control strategies such as PID and model-based control were incorporated into a family of controllers to create the hybrid control. Depending on the objective, the supervisory control determines the type of controller used for the specified task so as to maximize the advantages of each of the controllers. Before it was implemented into the actual robotic system the then proposed control approach was modeled and simulated using Matlab®. This control approach was developed based on a review of popular control approaches used in medical robotic systems, in order to look at the feasibility of having a uniform control strategy for a spectrum of medical robotic system. With unified control strategy it is possible to have a safety standard regulation for the medical robotic systems which is currently difficult to be done because of various control strategies adopted by each of the medical robotic systems.

Novel Propelling Mechanisms Based on Frictional Interaction for Endoscope Robot

In this work, two propelling mechanisms for a medical endoscope robotic system that can effectively move inside the intestinal track with minimum tissue damage were proposed. The first propelling mechanism utilized the rotational motion of a spiral-shaped body, and the second used the expansion and contraction motion of a stretchable body covered with polymeric surface structures. Both mechanisms were based on the frictional interaction between the robot body and the intestine surface. Through experiment, the biotribological behaviors of these mechanisms were investigated, and the major design parameters to achieve effective propelling motion with minimum tissue damage were identified. The results of this work will aid in the design of new endoscope robots that have motion control capability with adequate safety.

脳動脈瘤コイル塞栓術用ワンサージョン手術システムの開発

Catheter based operations are increasingly being used as a minimally invasive surgery method. In endovascular coil embolization, two surgeons generally fill an aneurysm with embolization coils by the collaborative manipulation of a microcatheter and a coil delivery wire. Currently, medical robot systems are being developed to assist advanced minimally invasive surgery procedures and to overcome the shortage of medical specialists. In this study, a new surgery system that can be operated by only one surgeon is developed. This system consists of a foot switch controlled delivery wire driving unit, a wire insertion force sensor unified Y-connector, and an audio insertion force feedback speaker. Basic verification for this system was conducted using a silicone dummy aneurysm. The results confirmed that the delivery of the wire at a constant velocity by the wire delivery system is an effective method for coil delivery, and that only one surgeon can perform the same coil embolization procedure. In this paper we demonstrate the above said system features and the verification results of this system by conducting a coil embolization using a silicone dummy aneurysm.

DEA‐based efficiency evaluation of a novel robotic system for femoral neck surgery

Efficiency evaluation is important for expanding the acceptance and deployment of medical robots, but it is still an open issue. In this study, a data envelopment analysis (DEA)-based method was proposed and implemented with a novel robotic system for femoral neck surgery. Femoral neck surgeries with and without the assistance of the robotic system were modelled as decision-making units (DMUs). C(2)R model was chosen to calculate the relative efficiency. Clinical simulation experiments were performed with 12 Sawbone models and 24 cadaveric femurs, and 19 clinical cases were chosen to be the control group. The minimum value of the robotically assisted surgery was 1, and the minimum value of the traditional surgery was 0.741535, demonstrating the efficiency of the robotic system. This research showed that DEA-based efficiency evaluation is practical for medical robotic systems.

Potential applications of medical and non-medical robots for neurosurgical applications

The objective of the paper is to review the state-of-the-art in medical robotic systems used for different surgical applications, and to position and evaluate their concepts according to the design requirements of an innovative, robotized neurosurgical system, capable of performing tumor ablation or electrode positioning. A few other non-medical systems, which have interesting concepts, will also be discussed. The overall aim is to determine the robotic concept (structure, actuation, etc.) most applicable to specific tasks in neurosurgery. The first section of the article describes the requirements of the task and each important aspect is expressed by an evaluation criterion. Then, 59 systems are described, according to the fields of medical applications and the robotic concepts. An evaluation of the different systems is conducted, based on the five most significant criteria. However, the main characteristic assessed is the deployment capability of the system i.e. extension and retraction. The final section presents an overview of concepts transferable to neurosurgical applications. Continuum concepts, such as “elephant trunks”, seem to be the most adapted solutions, utilizing pneumatic and/or spring and/or cable actuations. Pneumatics offer deployment forces and cables can control and guide the deployment. The design of a new neurosurgical device should take into account these observations as a base.

WKA-1R Robot assisted quantitative assessment of airway management

The emerging field of medical robotics aims tointroduce intelligent tools for physician support. The main challenges for developing efficient medical robotic training systems are simulating real-world conditions of the task and assuring training effectiveness. High anatomic fidelity has been achieved in current systems, but they are limited to provide merely subjective assessments of the training progress. We simulated airway intubation using a unique medical robot and developed objective performance criteria to assess task performance. A patient simulation robot was designed to mimic real-world task conditions and provide objective assessments of training progress. The Waseda– Kyotokagaku Airway No. 1R (WKA-1R) includes a human patient model with embedded sensors. An evaluation function was developed for the WKA-1R to quantitatively assess task performance. The evaluation includes performance indices and coefficient weighting. The performance indices were defined based on experiments carried out with medical doctors and from information found in the medical literature. The performance indices are: intubation time, jaw opening, incisor teeth force, cuff pressure, tongue force and tube position. To determine the weighting of coefficients, we used discriminant analysis. Experiments were carried out with volunteers to determine the effectiveness of the WKA-1R to quantitatively evaluate their performance while performing airway management. We asked subjects from different levels of expertise (from anesthetists to unskilled) to perform the task. From the experimental results, we determined operator effectiveness using the proposed performance indices. We found a significant difference between the experimental groups by evaluating their performances using the proposed evaluation function (P < 0.05). The WKA-1R robot was designed to quantitatively acquire information on the performances of trainees during intubation procedures. From the experimental results, we could objectively determine operator effectiveness while providing quantitative task assessments.

Performance evaluation of a medical robotic 3D-ultrasound imaging system

3D-ultrasound (US) imaging systems offer many advantages such as convenience, low operative costs and multiple scanning options. Most 3D-US freehand tracking systems are not optimally adapted for the quantification of lower limb arterial stenoses because their performance depends on the scanning length, on ferro-magnetic interferences or because they require a constant line of sight with the US probe. Robotic systems represent a promising alternative since they can control and standardize the 3D-US acquisition process for large scanning distances without requiring a specific line of sight. The performance of a new prototype medical robot, in terms of positioning and inter-target accuracies (i.e., difference between measurements and ground truth values) was evaluated with a lower-limb mimicking phantom throughout the robot workspace. The teach/replay repeatability (i.e., difference between taught and replayed points) was also assessed. A mean positioning accuracy between 0.46 mm and 0.75 mm was found on all scanning zones. The mean inter-target distance accuracy varied between 0.26 mm and 0.61 mm. Teach/replay repeatability below 0.20mm was also obtained. Additionally, a 3D reconstruction of in-vitro stenoses was performed with the robotic US scanner. The quantification error of a 80% area reduction (AR) stenosis was 3.0%, whereas it was -0.9% for a less severe 75% AR stenosis. Altogether, these results suggest that the robot may be of value for the clinical evaluation of lower limb vessels over long and tortuous segments starting from the iliac artery down to the popliteal artery below the knee.

Recent Trend of Medical Support Robotic Systems and Expectation to Precision Engineering

Recent Trend of Medical Support Robotic Systems and Expectation to Precision Engineering