Keywords: Technology for assisted surgery and diagnosis
Abstract: A novel parallel Remote Center of Motion (RCM) mechanism is proposed for a surgical robot designed to perform minimally invasive needle-based interventions for lung cancer diagnosis and treatment. The proposed robot provides four degrees of freedom (DOFs) to orient and move a surgical needle within a spherical coordinate system. The RCM is beneath the skin surface to minimize the invasiveness of the surgical procedure while providing the required workspace. This compact, patient-mounted robot benefits from a design capable of measuring the pure interaction forces between the needle and the tissue. In this paper, the mechanism design and its specifications are described. The kinematic analysis is presented and isotropy of the mechanism for targeting tumors is studied. Finally, the performance of the proposed robot is evaluated experimentally.

Attachments: Video
Keywords: Technology for assisted surgery and diagnosis, Image and model-guided interventions
Abstract: Prostate biopsy and brachytherapy are commonly used for surgical interventions. In this paper, we present a three-dimensional (3D) pre-operative target localization algorithm and a real-time closed-loop control algorithm to robotically steer flexible needles with an asymmetric tip towards a real target in a prostate phantom. The phantom is composed of different tissues including rectal wall, bladder and prostate. The elasticities of these tissues are obtained using an ultrasound-based (acoustic radiation force impulse imaging) technique, and their geometry are obtained using magnetic resonance images. Six experimental cases are performed to evaluate the steering system while inserting the needle into a prostate phantom with different skin thicknesses, insertion angles and surface inclinations. The experimental results show that the target is reached by the needle in all trials. The mean targeting errors between the needle tip and the center of the target embedded in phantoms with 0 mm, 1.5 mm and 2.5 mm skin thicknesses are 1.12 mm, 0.93 mm and 0.49 mm, respectively. The variation of the insertion angle does not have an appreciable affect on the targeting accuracy. The mean targeting error during insertion into a phantom with an inclined surface is 0.85 mm. The results demonstrate the capability of proposed system to robotically steer needles towards a target for interventions in the prostate.

Attachments: Video
Keywords: Surgical navigation and robotics, Technology for assisted surgery and diagnosis, Locomotion and manipulation in robots and biological systems
Abstract: We propose an image-based control for a robotic endoscope holder during laparoscopic surgery. Our aim is to provide more comfort to the practitioner during surgery by automatically positioning the endoscope at his request. To do so, we propose to maintain one or more instruments roughly at the center of the laparoscopic image through different command modes. The originality of this method relies on the direct use of the endoscopic image and the absence of artificial markers added to the instruments. The application is validated on a test bench with a commercial robotic endoscope holder.

Keywords: Surgical navigation and robotics, Technology for assisted surgery and diagnosis, Prosthetic devices
Abstract: 　Robotic surgical assistant systems can transcend the precision of surgical procedure by integrating the position information of patient and robot in the surgical room. There are two conventional integration methods, the real-time position tracking and physically fixing. In clinical cases, the former has the problem of increasing radiation exposure; so physical fixation is more commonly used in robotic surgery. However, the conventional fixing methods are also not optimized and problems of invasiveness and rigidness of fixation are left unsolved. 　This paper deals with a body-mounted surgical assistance robotic system for percutaneous vertebroplasty. The robot is fixed on the human body surface by fixing device that utilizes jamming transition phenomenon and vacuum cup. The body-mounted robot system sets up the correct pathway for needle insertion. The system was fixed on human shape target with a 166±8 N suction force. The fixing rigidity of our system and accuracy of the needle guide control device has been evaluated by measuring the displacement during needle inserting operation. The displacement of the fixing device by the external force of needle inserting operation was 0.06 mm and 0.02◦ in RMS. The total displacement of needle guide was 1.66 mm and 1.24◦ in RMS. The total positioning error of the needle guide control device was 0.09 mm and 0.97◦ in RMS.

Keywords: Surgical navigation and robotics, Technology for assisted surgery and diagnosis
Abstract: This paper defines what the authors named Modular Operating Room, as a heterogeneous system with different subsystems and devices that should interact between them in a surgical scenario. This is an evolution of the concept of Intelligent Operating Room, that has led us to large and expensive OR. The paper uses ROS to define a new package that manages the communications between different devices that can appear in a surgical scenario, in such a way that the real surgical scenario can be made with any combination of these devices. One simplified application consisting on the automatic insertion of an endoscopic camera on a trocar is shown as an example of integration.

Keywords: Technology for assisted surgery and diagnosis
Abstract: Minimally-invasive surgery has revolutionized many medical procedures; however, it also impedes the ability to feel the interaction between the surgical tool and the anatomical part being operated on. In order to address this problem, it is necessary to obtain accurate measurements of the interaction forces exerted on the surgical tools during surgery. These forces can then be manifested to the surgeon via a haptic device or presented visually (visual-force feedback). This paper describes the use of a fiber optic device to measure and display to the surgeon interaction forces acting on an arthroscopic tool. The sensorization of the tool involves a simple, highly efficient and robust design and is ideally suited for use in a surgical training environment aimed at narrowing the gap between trainees and expert surgeons before the trainees proceed to their first surgery in vivo. The major advantages of using fiber optics include their small size, their local simplicity, their ease of sterilization, and their high sensitivity. In this paper, a complete low-cost sensing solution is described, including 1) fiber Bragg grating sensors, 2) high resolution electronic signal processing, 3) fabrication of the tool using a wire electrical discharge machine (EDM) and 3D metal sintering technologies. Experimental results demonstrate the accuracy and performance of the sensorized tool.

Attachments: Video
Keywords: Technology for assisted surgery and diagnosis, Vascular Biomechatronics, Neuro-robotics
Abstract: We propose a novel biomedical platform of a cubic (artificial) eggshell containing a chick embryo. The use of this proposed platform can eliminate the use of large animals as experimental models, making it more ethically accepted. It also has the advantages of low cost and a small size. The specific design and fabrication method of the cubic eggshell uses polydimethylsiloxane (PDMS) and polycarbonate, which were shown to achieve the required specifications of the proposed platform. The viability of the chick embryo in the cubic eggshell was confirmed through basic experiments. Finally, surgical tools were inserted into the cubic shell and the internal organs were operated on to confirm the use of the developed cubic shell as an appropriate platform for microsurgical training.

Keywords: Image and model-guided interventions, Technology for assisted surgery and diagnosis, Surgical navigation and robotics
Abstract: A novel compact and lightweight patient-mounted MRI-compatible robot has been designed for MRI image-guided interventions. This robot is intended to enable MRI-guided needle placement as done in shoulder arthrography. The robot could make needle placement more accurate and simplify the current workflow by converting the traditional two-stage arthrography procedure (fluoroscopy-guided needle insertion followed by a diagnostic MRI scan) to a one-stage procedure (streamlined workflow all in MRI suite). The robot has 4 degrees of freedom (DOF), two for orientation of the needle and two for needle positioning. The mechanical design was based on several criteria including rigidity, MRI compatibility, compact design, sterilizability, and adjustability. The proposed workflow is discussed and initial MRI compatibility experiments are presented. The results show that artifacts in the region of interest are minimal and that MRI images of the shoulder were not adversely affected by placing the robot on a human volunteer.

Keywords: Technology for assisted surgery and diagnosis, Surgical navigation and robotics
Abstract: We investigated the relationship between workspace reduction due to collisions and the distance between the endoscope and target organ to develop a new algorithm for endoscope navigation in pediatric endoscopic surgery. Proper endoscope position is important for pediatric endoscopic surgery: the endoscope needs to get close to the target organ to obtain a suitable field of view. However, collisions between the endoscope and instrument are more likely to happen when the endoscope get close to the target. This reduces the workspace and complicates pediatric endoscopic surgery. We developed a simplified model of the endoscope and instrument to simulate the influence of the distance between the endoscope and target on the workspace reduction due to collisions. The simulation results showed how the workspace reduction was affected. Based on the results, we will perform further experiments to determine the appropriate endoscope position

Keywords: Surgical navigation and robotics, Image and model-guided interventions, Technology for assisted surgery and diagnosis
Abstract: One standard procedure in minimally invasive surgery is the endoscopic submucosal dissection (ESD), where neoplastic mucosa is being removed. The standard endoscopes and flexible instruments currently used in everyday routine have limited maneuverability and are controlled in an unintuitive manner. To overcome these drawbacks we propose a telemanipulation system capable of independently controlling two standard flexible endoscopic instruments with sufficient triangulation that is comparable to the dexterity of classical open surgery. By using the rapid manufacturing technique selective laser sintering (SLS) of a biocompatible polyamide, we want to examine basic design principles to print our telemanipulation system in one part and to individualize its characteristics for patient specific print-out in the future. In this paper we give an overview of our system from the mechanical design via control and actuation concept to visual environment perception.

Keywords: Surgical navigation and robotics, Human-machine interaction, Technology for assisted surgery and diagnosis
Abstract: Due mainly to drastically shortened recovery times and lower overall cost, minimally invasive surgery (MIS) is growing standard for many surgical interventions. However, associated loss of visual depth perception, difficult hand-eye coordination and distorted haptic sensation tend to complicate this task for the surgeon.

In this paper, we explore the potential of simple visual, haptic or combined visual and haptic cues for intuitively assisting surgeons in moving their instrument tip within a predefined 3-D plane. 23 subjects carried out trajectory following tasks within a plane under provision of 9 different combinations of visual and haptic guidance feedback. Evaluated forms of haptic feedback encompassed both tactile cues and kinaesthetic feedback using soft virtual fixtures.

Results show clear superiority of soft guidance virtual fixtures over other forms of feedback, leading to performance levels above those obtained in open surgery. However, promising results for the use of cutaneous vibrotactile feedback are also obtained, with potential for integration in MIS tool handles.

Keywords: Surgical navigation and robotics, Human-machine interaction, Biomechatronic and human-centred design
Abstract: A command and control interface for intraoperative endoscope positioning must be intuitive, simple, intrinsically safe and reliable. Voice commands are widely used in commercial and experimental robotic-assisted remote-controlled surgical systems and must comply with those requirements. This paper presents a design proposal and implementation of an integrated voice-activated control interface as well as its associated command strategy. It comprises an isolated word speech recognition module based on the IBM SMAPI programming library, a task management state machine and a RS232 communication module

Keywords: Technology for assisted surgery and diagnosis, Image and model-guided interventions, Surgical navigation and robotics
Abstract: Abstract Percutaneous surgical procedures depend on the precise positioning of the needle tip for effectiveness. Although, robustly locating the tip of the needle still represents a challenge, specially when flexible needles are used. An imaging technique widely used for this task is 2D ultrasound, however the low signal/noise ratio makes it difficult to apply conventional image processing techniques. In this work, we propose an alternative method for detecting the needle in an ultrasound image and tracking it during a complete insertion. The proposed method combines a Multilayer Perceptron network with a Kalman filter estimator for improving robustness. In preliminary experimental characterization, we acquired ultrasound images for creating the data set and evaluated the performance of the tracker with a complete insertion video. However the tracking performance is still far from optimal, the obtained results suggests the neural network approach to be a feasible alternative to this problem.

Keywords: Human-machine interaction
Abstract: Quantitative analysis of surgeons' motor variability during the surgical practice is still scarce. Therefore, a framework for the analysis of surgeon upper-body postural variability during laparoscopic procedures was developed. 3D kinematics analysis gave us information regarding the head posture adopted by the surgeons with respect to the trunk and how this varies during surgical training activities. Furthermore, surgeon's upper-body joint variability was quantified using the framework of the Uncontrolled Manifold hypothesis, allowing to separate the combination of joint angles that were equally able to stabilize head mean posture on sagittal plane for those solutions that were destabilized head mean posture. The results showed that the underlying framework was able to quantify surgeons' motor variability, providing inspiration for new human-machine interaction designs, as well as more targeted ergonomics assessments.

Keywords: Vascular Biomechatronics, Technology for assisted surgery and diagnosis, Prosthetic devices
Abstract: This paper presents a computational simulation and implementation of electromechanical actuator performance of the Implantable Centrifugal Blood Pump (ICBP) as part of a speed controller study to avoid aortic valve stenosis. The ICBP as Left Ventricular Assist Device (LVAD) is an electromechanical device designed for long-term assist left heart in performing its functions. The centrifugal pumps are controlled by varying the rotor (impeller) speed. ICBP successful operation depends on an appropriate rotational speed control system, ensuring: 1) no reverse flow through the pump during left ventricle diastolic phase, and 2) aortic valve correct opening, avoiding later valve stenosis. A computational model of the actuator done in Matlab / Simulink (R2010b, Mathworks, Massachusetts, USA) was used in the simulations. Control and signal processing was used Labview (National Instruments, Austin, USA). Signals equivalent to intraventricular pressure and a variable rotational reference were used to evaluate motor and speed controller performance. Speed values were chosen so that pressure pump exceeds intraventricular pressure only after the opening of aortic valve. The proposed controller is Proportional-Integral (PI) type. The simulation results were satisfactory, no steady error in response speed. Practical tests showed satisfactory results to follow speed reference signal, as simulated. Future studies will evaluate the bands control.

Keywords: Human-machine interaction, Biological systems modeling
Abstract: The aim of the present study is to analyse changes in the diaphragmatic electromyography integral, as a direct expression of the patients inspiratory effort and index of neural respiratory drive, and parameters associated with ventilatory function in patients with prolonged weaning under Pressure Support Ventilation (PSV) and Neurally Adjusted Ventilatoy Assist (NAVA). Five patients affected by neuromuscular diseases were recruited. Each patient underwent a sequence of decreasing inspiratory support levels under NAVA and PSV, randomly assigned, from a baseline to a final level. At baseline, the value of diaphragmatic electromyography integral was higher under NAVA compared to PSV and increased in both ventilation modes progressing to final level. Higher values of inspiratory time and neural inspiratory time were observed in PSV at final level compared to baseline level. Conversely, a significant decrease of neural inspiratory time from baseline level to final level was observed in NAVA. Tidal volume at final level was significantly lower than at baseline level in both ventilation modes. These preliminary results show that in prolonged weaning patients affected by neuromuscular disease NAVA ventilation is associated to a higher diaphragmatic electromyography activity compared to PSV with same level of ventilation and subjective comfort.

Keywords: Prosthetic devices, Human-machine interaction, Rehabilitation and assistive robotics
Abstract: In the last 30 years very innovative prosthetic hands have been developed. Nevertheless, most of prosthetic hands are basically simple grippers with one or two degrees of freedom (DOFs) providing low functionality. Efforts have been made to improve the performance of devices so that they are as similar as possible with the human hand by exploring recent progresses in mechatronics technology. A major challenge in the development of prosthetic hands with a greater number of DOFs and, consequently, better functionality is to unite the entire system in a compact and lightweight design, besides provide some sensorial informations to the amputee. The goal of this work is to develop a prosthesis concept which brings several advantages such as: lightweight, low energy consumption, reduction in volume, simple control and flexibility. In addition, the system is able to provide prehension force feedback. The mechanical design of a finger is described, which composes an artificial hand prototype of two active fingers, with three DOFs each one, and a static thumb. A force sensor provides feedback to the user through mechanical vibrations, ensuring greater safety to grasp an object. Also, a myoelectric control is implemented such that amputees are able to control their artificial limbs in a more natural way.

Keywords: Technology for assisted surgery and diagnosis, Biological systems modeling, Image and model-guided interventions
Abstract: The main aim of this preliminar study was to support the orthopedic surgeon with information about the position of the graft placement of the ACL, using the data provided by a spatial model of the knee. A mathematical model available in the literature and based on the theory of mechanism has been here reimplemented. In particular, the numerical approach to the definition of the model has been modified respect to the original by introducing the quaternion algebra and the differential evolution algorithm. This methodology has already shown to be capable to produce mechanisms that match the natural motion of the knee. Any implementation of it may thus be useful in the preoperative planning with information of the position of the graft placement of the ACL.

Keywords: Technology for assisted surgery and diagnosis, Biological systems modeling
Abstract: Multislice CT scanners have characteristics that offer advantages in clinical applications. The technology is particularly suited for medical applications that require high time performance and high spatial resolution. Patellofemoral tracking is one application that can benefit from multi slice CT characteristics. It is performed to study disturbances in the normal tracking mechanism of the patellar femoral joint. The patellofemoral instability is one condition that generates pain, functional impairment and often requires surgery as part of orthopedic treatment. The analysis of the patellofemoral dynamics has been performed by several medical image modalities. However, most of the methods are based on measurements in 2D images, such as the patellar tilt angle and the lateral shift. Besides, the acquisition protocols are mostly performed at fixed angles. The use of helical multislice CT scanner can allow the capture and display of the joint´s movement performed actively by the patient. In this work we evaluate the use of multi slice high resolution CT technology to evaluate the biomechanics of the patellofemoral joint. The quantitative analysis of the movement is performed by extracting displacement parameters in 3D images between different knee positions. Analyses of these parameters for all frames provided real 3D information about the patellar displacement.

Keywords: Prosthetic devices, Rehabilitation and assistive robotics, Human-machine interaction
Abstract: This work presents the design of a variable-damping prosthesis for above-knee amputees. The proposed low cost system is self-contained and based on a four-bar polycentric mechanism, in which a magnetorheological linear damper is integrated to enable variable-damping control. The paper also describes a control strategy based on a Finite State Machine, which will modulate the damping level according to the actual state of the gait cycle. Preliminary tests on an amputee subject provided a satisfactory performance of the system while operating in the passive mode, i.e., simulating situations when the battery runs out, and also enabled correct identification of gait events.

Keywords: Prosthetic devices, Biologically-inspired systems, Wearable assistive and augmenting devices
Abstract: Many upper limb amputees are faced with the difficult challenge of using a prosthesis that lacks tactile sensing. State of the art research caliber prosthetic hands are often equipped with sophisticated sensors that provide valuable information regarding the prosthesis and its surrounding environment. Unfortunately, most commercial prosthetic hands do not contain any tactile sensing capabilities. In this paper,a fabric based tactile sensor system was designed, built, and evaluated for use with upper limb prosthetic devices. Despite its simplicity, we demonstrate the ability of the sensors to determine object contact and perturbations due to slip during a grasping task with a prosthetic hand. This suggests the use of low-cost, customizable, textile sensors as part of a closed loop tactile feedback system for monitoring grasping forces specifically in an upper limb prosthetic device.

Keywords: Rehabilitation and assistive robotics, Human-machine interaction, Neuro-robotics
Abstract: The use of robotics in rehabilitation has shown to have a positive outcome when applied to stroke patients and other movement based therapies. Despite recent studies looking at these type of therapies in helping patients with Phantom Limb Pain very few have looked at employing the elements that make robotics successful with stroke patients towards amputees. Phantom Limb Pain affects the majority of amputees, resulting in the need for further study due to the vast range of potential treatments available. This paper examines the effects of Phantom Limb Pain, its treatment, paradigms based on robotic rehabilitation and provides an outline of a possible therapy method based on an immersive system providing proprioceptive and kinaesthetic feedback to the user while performing a manipulation task.

Keywords: Prosthetic devices, Technology for assisted surgery and diagnosis, Wearable assistive and augmenting devices
Abstract: Ligament tensioning is a key step in Total Knee Arthroplasty surgery. The surgeon has to manually set proper tension conditions for the two lateral ligaments of the knee. Inaccuracies may lead to severe postoperative complications and, in the worst-case scenario, to revision surgery. Unfortunately, suboptimal balance conditions are unavoidable and no assistance tool has been developed up to now to help the surgeon during the surgery. The goal of this work is to propose an instrumented tibial component able to evaluate ligament balance conditions after surgery and to monitor their evolution in the postoperative period. Thanks to an embedded actuation system, optimal ligament tension values can be restored so as to improve the prosthesis lifespan and avoid the need for revision surgery.

Keywords: Prosthetic devices, Locomotion and manipulation in robots and biological systems, Biologically-inspired systems
Abstract: The designs of available lower extremity powered prostheses are focused on a single degree of freedom (DOF) in sagittal plane, allowing the control of their ankle joints in dorsiflexion and plantarflexion. The human gait however, shows that the ankle movements in both sagittal and frontal planes are significant even during walking on a straight path. Additionally, there is a significant change in the ankle movements during straight walking compared to turning and cutting, especially in frontal plane. A better understanding of the ankle characteristics in both sagittal and frontal planes may result in the design of significantly more effective lower extremity prostheses that mimic the ankle function and improve the agility of gait. In this paper, the ankle rotations are estimated during step turn and cutting to provide evidence for necessity of a multi-axis design while providing the preliminary design parameters for a prototype multi-axis powered ankle-foot prosthesis. It is shown that the proposed cable-driven prototype is capable of closely mimicking the ankle movements in both sagittal and frontal planes during turning and walking on a straight path.

Keywords: Technology for assisted surgery and diagnosis
Abstract: Laparoscopic surgery has to be operated with an assistant during surgery, which requires training and high cooperation work between the surgeon and assistants. The objective of this study is to develop a laparoscopic system providing intuitive maneuverability. We develop a Robotic Flexible Laparoscope System (RFLS) with compliance effect including adaptive impedance and velocity control to assist in laparoscopic surgery. The system is controlled by the surgeon’s head movements, so that the surgeon can use his/her hands to manipulate the laparoscopic instruments while maneuvering the laparoscope intuitively, and thus replace the assistant and enhance the efficiency of the surgery. The laparoscope movements are controlled by adaptive impedance control approach, the compliance effect, the impedance with the integral and derivative control design, and the reaction torque observer. We also add zero-point-correcting algorithm and singular situation elimination algorithm. Furthermore, scalable ratio adjustment of head movement with respect to laparoscope movement is also included in our system. This system makes surgeon-in-charge maneuver the laparoscope intuitively without communication and coordination with assistant needed in conventional way. As a result, it is expected to reduce manpower and time during surgery. Experimental results demonstrate that the articulated laparoscope can always follow user’s head motion in all necessary orientations.

Keywords: Technology for assisted surgery and diagnosis, Human-machine interaction, Surgical navigation and robotics
Abstract: Retinal Vein Occlusion is a common retinal vascular disorder which can cause severe loss of vision. Retinal vein cannulation is a promising treatment, but given the small diameter of retinal veins and the surgeon's limited positioning precision, it is considered too risky to perform this procedure manually. The authors previously reported on the development of both a robotic comanipulation and telemanipulation system which have the potential to augment the surgeon's positioning precision. This work investigates the potential benefit of these systems for retinal surgery. For this purpose, a targeting test setup was developed to quantify the attainable positioning precision one can expect when using the robotic systems during procedures like retinal vein cannulation. Ten subjects completed targeting tests in a free-hand, comanipulation and telemanipulation fashion. Results show that both the usage of the comanipulation and telemanipulation system significantly improve the positioning precision compared to a free-hand test. The telemanipulation system currently outperforms the comanipulation system with respect to precision, while subjects address the unprecedented ease of use of the comanipulation system.

Attachments: Video
Keywords: Locomotion and manipulation in robots and biological systems, Micro/nano technologies in medicine and biology, Biologically-inspired systems
Abstract: This work addresses the magnetic-based control of a helical robot and the mitigation of the magnetic forces on its dipole moment during radial steering using rotating permanent magnets. A magnetic system with two synchronized permanent magnets that rotate quasistatically is used to move the helical robot (length and diameter of 12.5 mm and 4 mm, respectively). We experimentally demonstrate that using two synchronized permanent magnets for radial steering of a helical robot achieves higher motion stability, as opposed propulsion using single rotating dipole field. The two synchronized dipole fields decrease the lateral oscillation (average peak-to-peak amplitude) of the helical robot by 37%, compared to the radial steering using a single dipole field at angular velocity of 31 rad/s. We also show that driving the helical robot using two synchronized rotating magnets achieves average swimming speed of 2.1 mm/s, whereas the single rotating dipole field achieves average swimming speed of 0.4 mm/s at angular velocity of 31 rad/s for the rotating permanent magnets. The proposed configuration of the helical propulsion allows us to decrease the magnetic forces that could cause tissue damage or potential trauma for in vivo applications.

Keywords: Technology for assisted surgery and diagnosis
Abstract: Although some technologies have been developed to measure tool–tissue interaction forces during minimally invasive surgery (MIS), none of these technologies have been approved for use in humans. The primary factor preventing the use of sensorized instruments in humans is their inability to withstand the stringent conditions present during cleaning and sterilization. This paper presents a series of experiments that were performed to develop a sterilizable instrument capable of measuring tool–tissue interaction forces in three degrees of freedom using strain gauges. The experiments provided an appropriate choice of cables and connectors, as well as an optimal combination of strain gauge adhesives and coatings that allow the sensors to withstand autoclave sterilization. A prototype of the sensorized instruments was developed and tested. The final prototype was able to withstand a sterilization cycle with excellent results (0.10–0.21 N accuracy, 0.05–0.20 N repeatability and 0.06–0.21 N hysteresis depending on the measurement direction). This work shows that autoclave sterilization is possible for a strain-gauge instrumented device.

Keywords: Surgical navigation and robotics
Abstract: In this paper the issue of kinematic instability for concentric tube robots is studied when the following two conditions are considered: (a) the robot consists of more than two concentric tubes, and (b) the tubes consist of straight sections followed by curved sections. In this paper, we use the term “kinematic instability” when the tip position of robot in the Cartesian domain jumps from one equilibrium point to another while having a constant joint space configuration. This implies that in unstable configurations, the “forward kinematics” of the robot will have multiple solutions for one set of joint space variables. In this paper a novel framework is proposed that can calculate the stability condition for the robots consisting of multiple tubes with straight sections without solving the nonlinear ordinary differential equations. The resulting conditions restrict the pre-curvatures and length of the tubes, as a design factor, to guarantee kinematic stability within the whole workspace of the robot.

Attachments: Video
Keywords: Micro/nano technologies in medicine and biology, Image and model-guided interventions, Surgical navigation and robotics
Abstract: This paper demonstrates closed-loop control of self-propelled microjets using feedback extracted from B-mode ultrasound images. Previous work on control of self-propelled microrobots has mainly employed video cameras equipped with microscopic lenses in order to obtain the required feedback. Nonetheless, in medical applications such as targeted drug delivery, the use of video cameras might be unsuitable for localizing microrobots that navigate within the human body. This issue is a major obstacle for transferring medical microrobotic technologies into the clinic. On that account, the first reported methods and results on control of self-propelled microjets using ultrasound equipment are provided herein. In order to exploit the microjets’ self-propulsion mechanism, their motion is directed towards a predefined target by exerting magnetic torques to steer them. Binary image analysis techniques are used to estimate the microjet’s position from the ultrasound images. Two air-cored coils are used to generate the steering torques within a plane. Coil currents are calculated using the estimated position error. Results show that our system employing ultrasound images allows control of microjets at an average velocity of 156 um/s and with an average tracking error of 250.7 um. As a reference, when microscopic image feedback is used in the setup, an average velocity and tracking error of 207 um/s and 183.2 um, respectively, are observed.

Attachments: Video
Keywords: Rehabilitation and assistive robotics, Human-machine interaction
Abstract: In the past decades there has been an increasing interest in the design of robotic platforms suitable to assist the conventional motor therapy and/or to study human motor control. Most of the proposed solutions, however, come with intrinsic limitations that in turn limit the final use of the device itself. For instance, encumbrance, sophisticated control architectures and high costs translate into cumbersome and expensive devices whose diffusion is still limited to laboratories and specialized clinical settings. This paper presents a novel, two degrees-of-freedom planar device conceived according to three main principles: emph{portablility}, emph{cost-effectiveness} and emph{ease of control}. The key ingredient of the device is a planar {em H-shaped cable differential mechanism} which ensures a constant Jacobian and a homogeneous perceived inertia over the entire workspace. The paper presents the mechanical design as well as the performance evaluation in terms of bandwidth, Z-width and perceived impedance.

Attachments: Video
Keywords: Neuro-robotics, Neuroengineering, Biologically-inspired systems
Abstract: Emulating how humans coordinate articulated limbs within the brain's power budget promises to accelerate progress in building autonomous biomimetic robots. Here, we used a neuromorphic approach---low-power analog silicon spiking neurons---to control an articulated robot in real-time. We obtained a closed-form control function that computes robot motor torques given the robot's joint angles (state) and desired end-effector forces; factorized the function into a set of sub-functions over five unique three-dimensional domains; and regressed each sub-function on to the steady-state spiking responses of one out of five silicon spiking-neuron pools. The spiking pools controlled a three degree-of-freedom robot's motor torques in real-time and performed reaches to arbitrary locations in space with less than 2cm root-mean-square trajectory tracking error (of an analytical controller). The controller is compliant and can draw shapes with a pen on a dynamically perturbed surface while remaining stable. Using force control resulted in linear responses to perturbations in end-effector coordinates (task-space), which effectively filtered noise due to neuron spikes. Factorizing the controller reduced the neural regression's complexity to cubic in the dynamic range of the robot's state and desired forces. Doing so made acquiring spiking responses for regression tractable in time (~2-3min), and enabled reliable trajectory tracking with only 1280 neurons. This is the first time a neuromorphic system has achieved real-time manipulation for an articulated robot with three or more degrees-of-freedom.

Keywords: Rehabilitation and assistive robotics, Human-machine interaction, Wearable assistive and augmenting devices
Abstract: Currently, a considerable group of adult Duchenne Muscular Dystrophy patients lives with severe physical impairments and strong dependency on care. Active arm supports can improve their quality of life by augmenting their arm's residual motor capabilities. This paper presents the design and control of an experimental active elbow support specially made to investigate different control interfaces with adult DMD patients. The system can be controlled either with EMG or force signals which are used as inputs for an admittance-based controller. A preliminary test with a 22-year-old DMD patient with no arm function left, shows that the system is capable of successfully supporting the elbow flexion-extension movements using the low-amplitude EMG and force signals that still remained measurable.

Keywords: Rehabilitation and assistive robotics, Wearable assistive and augmenting devices
Abstract: This paper introduces the design of SoleSound, a wearable system designed to deliver ecological, audio-tactile, underfoot feedback. The device, which primarily targets clinical applications, uses an audio-tactile footstep synthesis engine informed by the readings of pressure and inertial sensors embedded in the footwear to integrate enhanced feedback modalities into the authors' previously developed instrumented footwear. The synthesis models currently implemented in the SoleSound simulate different ground surface interactions. Unlike similar devices, the system presented here is fully portable, and can therefore be utilized outside the laboratory setting. A first experimental evaluation indicates that the device can effectively modulate the perception of the ground surface during walking, thereby, inducing changes in the gait of healthy subjects.

Attachments: Video
Keywords: Human-machine interaction, Wearable assistive and augmenting devices, Prosthetic devices
Abstract: In rehabilitation robotics it is highly desirable to find novel human-machine interfaces for the disabled, in particular to substitute or augment surface electromyography (sEMG), trying to keep at the same time its easiness of use, precision and non-invasiveness. In this paper we design and demonstrate one such device, based upon Force-Sensing Resistors (FSRs). An array of 10 FSRs was wrapped around the proximal section of the forearm of ten intact subjects engaged in pressing on an accurate force sensor with their fingers (this includes the rotation of the thumb). The FSRs would detect the forearm surface deformations induced by muscle activity; the signals provided by the FSRs were then matched to the recorded forces. The experimental results show that finger forces can be predicted using this device with the same accuracy obtained in literature using sEMG. The device, even as an academic prototype, weighs about 65 grams and costs around 50 EUR. Thus, it is remarkably light and cheap in comparison to standard sEMG electrode arrays.

Keywords: Locomotion and manipulation in robots and biological systems, Biological systems modeling, Biologically-inspired systems
Abstract: Balancing the upper body as one of the main features in human locomotion is achieved by actuation of the compliant hip joints. Using leg force feedback to adjust the hip spring is presented as a new postural control technique. This method results in stable and robust running with the conceptual SLIP model which is extended by addition of a rigid trunk for upper body. Besides providing stability, this approach can represent the virtual pendulum (VP) concept which was observed in human/animal locomotion. Even more, the duality of this controller with virtual pendulum posture controller (VPPC) was mathematically shown. Such a mechanism could be also interpreted as a template for neuromuscular model.

Keywords: Locomotion and manipulation in robots and biological systems, Biological systems modeling, Biologically-inspired systems
Abstract: Patients suffering from diabetic neuropathy present disturbed kinetic, kinematic and electromyographic gait patterns. These disturbances have been experimentally related with plantar ulcerations. However, experimental data are limited because it is not possible to record certain muscle groups (e.g, illiopsoas). In this respect, computational simulations complement the experiments. Our aim is to simulate how the neuromusculoskeletal system of diabetic neuropathic individuals deals with a reduced distal muscle function during level gait. It was hypothesized that proximal muscle compensates the reduced distal muscle function. We used a seven segment planar musculoskeletal model of the body with 8 muscles in each leg. Normal gait muscle excitation patterns were used as reference input in forward dynamics simulations. In order to simulate the neuropathic gait condition, those reference excitations were modified according to functional changes found in diabetic gait. The tibialis anterior (3,75%) and gastrocnemius (15%) excitation reduction along with iliopsoas (11,25%) and hamstrings (7,5%) excitation increase during push-off, guaranteed larger pre-swing hip flexion and smaller hip extension during stance. This motion pattern was not observed when hamstrings excitation remained unchanged. Ankle plantar-flexion during push-off and ankle flexion during swing decreased as the gastrocnemius and tibialis were functionally reduced. The musculoskeletal model was able to represent the hip strategy possibly adopted by the diabetic neuropathic patients during gait as an adaptation to loss of function in distal muscles. The increase in hamstrings function is crucial to improve the model dynamic stability opening new approaches to therapeutic handling of these patients.

Keywords: Locomotion and manipulation in robots and biological systems, Rehabilitation and assistive robotics, Biomechatronic and human-centred design
Abstract: This work analyses the obstacle crossing during gait and compares the behavior of humans with a robot model. The aim of the study is to compare the obstacle crossing task between human subjects, performing the task both with vision and blindfolded, and ZMP biped robots. It was hypothesized that the trajectories of the hip joint and the foot of the blindfolded subjects would resemble those of the robot. Seven subjects walked on a flat surface with an obstacle of 0.26 m height and crossed the obstacle successfully 30 times under two conditions: blindfolded and with normal vision. The motion of the leading limb was recorded by video at 60 Hz. There were markers placed on the subject’s hip, knee, ankle, rear foot, and forefoot. The following parameters were calculated: critical time, vertical foot position and average step velocity. A robot model with inertial parameters matched with the subjects and a controller based on the ZMP criterion was developed. The hip joint and foot trajectories of humans and robots were assessed and compared. Unavailability of visual information resulted in different strategies to cross the obstacle, like a higher toe clearance or lower step speed. Without vision, the crossing pattern seems to be more cautious and slower than with vision, thus resembling that of the robot with ZMP. The hip was kept behind until the foot has overtaken the obstacle as a possible mechanism to maintain a safe base of support if a trip occurs. This is also supported by the data showing that blindfolded behaved with an intermediate pattern between vision and robot in the hip antero-posterior trajectory. In this context, it is possible to extract some conclusions to improve the ZMP stability criterion of biped robots.

Keywords: Biomechatronic and human-centred design, Biological systems modeling
Abstract: We propose a new heel-contact toe-off walking model based on the Linear Inverted Pendulum (LIP) model, which because of the linearity and the ease of manipulation of the equations, could be considered to be advantageous for a future online implementation for the generation of walking patterns. This new model is based on the so called functional rockers of the foot (heel, ankle and forefoot rockers), each of which are modeled as an inverted pendulum, changing the ground contact point position of the inverted pendulums for each rocker. We focus on the motion of the Center of Mass (CoM) in the saggital plane, as it is the plane on which the rockers take place, but also generate the motions on the frontal plane. The model proved to work for constant velocity, accelerating and decelerating gaits, and the dynamic effects of heel-contact and toe-off could be corroborated in the Zero Moment Point (ZMP) graphs. The implementation of this model could improve the human likeness of the motions, as well as the stability of the locomotion.

Keywords: Human-machine interaction, Rehabilitation and assistive robotics
Abstract: Smart Walkers should be able to safely deal with inclinations in order to become a device effectively useful in the daily life of the elderly population. This paper presents a novel model of human-walker interaction on slopes. The interaction parameters are obtained from a Laser Range Finder (LRF) and an Inertial Measurement Unit (IMU). This model is integrated into the conventional closed control loop as a supervisor block. This block modifies, based on inclinations, the control set points to provide an adaptable human-walker desired position to improve comfort and safety and enhance user's confidence in the walker. The practical evaluation shows that the parameters extracted from the natural behavior of the user and the estimated set points determined with the model proposal are highly correlated, presenting a similar trend. This correlation allows performing a more natural control.

Keywords: Technology for assisted surgery and diagnosis
Abstract: The requirement of safe child delivery is increasing in developed countries in these decades. We have developed an obstetric forceps contouring the infant’s head surface with stiffness-controlled pads. The stiffness of the pad is controlled by using air pressure regulation based on jamming transition. The proposed forceps has two soft material pads facing to the infant’s head. The proposed forceps is first thin to get safely inserted into the delivery cavity. The granular tetrapod particles are then injected into the pads to contour the infant’s head surface. By vacuuming the inside air of the pads, the particles interlock each other and the pads move onto the solid-like phase. In the experiments, the proposed method worked effectively to decrease the pressure onto the infant’s head during delivery assistance and consequently made the operation safer.

Keywords: Technology for assisted surgery and diagnosis
Abstract: A customized load cell is developed to quantitatively evaluate the three-dimensional orthodontic actions applied during treatment. The force-torque sensor is part of a platform composed of 14 load cells, each one equipped with 6 strain gauges and interfaced with a tooth. The particular shape of the load cell allows detecting 6 mechanical actions independently that the tooth is subjected to. At the same time, a dedicated acquisition system is used to collect data simultaneously. The load cell is calibrated by applying known loads in a range between 0 N and 2 N. For each strain gauge’s output, good linearity (0.83 < R2 < 0.99) and great repeatability (10-4% < STD < 1.4%) are observed. Within this work, the load cell design, fabrication and characterization are described.

Keywords: Technology for assisted surgery and diagnosis, Technology Assessment, Ethical and Social Implications of Biorobotics and Biomechatronics, Rehabilitation and assistive robotics
Abstract: Retinal microsurgery requires the manipulation of extremely delicate tissues by various micron scale maneuvers and the application of very small forces. Among vitreoretinal procedures, membrane peeling is a standard procedure requiring the delamination of a very thin fibrous membrane on the retina surface. This study presents the development and evaluation of an integrated assistive system for membrane peeling. This system combines a force-sensing motorized micro-forceps with an active tremor-canceling handheld micromanipulator, Micron. The proposed system (1) attenuates hand-tremor when accurate positioning is needed, (2) provides auditory force feedback to keep the exerted forces at a safe level, and (3) pulsates the tool tip at high frequency to provide ease in delaminating membranes. Experiments on bandages and raw chicken eggs have revealed that controlled micro-vibrations provide significant ease in delaminating membranes. Applying similar amount of forces, much faster delamination was observed when the frequency of these vibrations were increased (up to 50 Hz).

Keywords: Surgical navigation and robotics, Technology for assisted surgery and diagnosis
Abstract: Lack of force sensing is one of the most formidable technical challenges in retinal microsurgery. Incorporating high sensitivity force sensing into the ophthalmic tools has the potential to provide the surgeon useful force feedback and to enable safe robotic assistance. This paper presents a new design of a three degrees of freedom force sensing instrument based on fiber Bragg grating sensors. A new flexure is developed to achieve high axial force sensing sensitivity and low crosstalk noise. The force sensing segment of the tool, located directly proximal to the tool tip, is Ř0.9×8 mm. An extensive calibration shows that the force sensor can measure the transverse and axial force up to 21 mN with 0.5 mN and 3.3 mN accuracy, respectively. The new flexure design demonstrates the potential to improve axial force sensing. Analysis of the experiment results suggests improvements for the future iteration.

Keywords: Technology for assisted surgery and diagnosis, Image and model-guided interventions, Surgical navigation and robotics
Abstract: Acoustic radiation force (ARF)-based measurements of tissue elasticity require transmission of an acoustic pulse and ultrasound image-based tracking of the resulting tissue displacements. This technique provides diagnostic information about various disease states of tissue. One limitation, however, is the dependency on applied probe pressure, which is difficult to control manually and prohibits standardization of quantitative measurements. To overcome this limitation, we introduce a custom-built robot that controls probe contact forces. The robot was evaluated in an in vivo canine prostate and ex vivo bovine liver. Markers implanted in the prostate were visualized with 3D probe contact forces (i.e. tissue pre-loading) that ranged 10-11 N. The resulting displacement of the markers were evaluated to estimate the variability in pre-loading strains that could exist prior to making an ARF-based elasticity measurement. One standard deviation of corresponding strains ranged 0-2%. In the ex vivo liver, differences in speckle-tracked tissue displacements were observed when the probe sustained tissue contact as it returned to its initial position, indicating that there is a potential benefit in losing tissue contact prior to taking measurements that will be used for standardization (e.g. to avoid differences in pre-loading and corresponding tissue elasticity). Results are promising for the introduction of robotic systems to control the applied probe pressure for ARF-based measurements of tissue elasticity.

Keywords: Rehabilitation and assistive robotics, Human-machine interaction
Abstract: The goal of this study is to evaluate the effects of robot-assisted upper limb therapy in subacute and chronic stroke patients using a set of kinematic parameters evaluated during each of the first 15 rehabilitation sessions.Twenty-four post-stroke subjects, twelve subacute and twelve chronic, participated in the study. A 2 DOFs robotic system was used for upper limb training. Kinematic parameters related to the speed and smoothness measured at the robot’s end-effector were computed. Outcome clinical measures show a decrease in motor impairment at half-treatment both in chronic and subacute patients. Significant improvements in kinematic parameters within the first 15 sessions were observed only in subacute patients.

Keywords: Neuroengineering, Biological systems modeling, Locomotion and manipulation in robots and biological systems
Abstract: The tacit representation of muscle coordination has been a central issue of research on motor control. To unravel the mechanisms underlying voluntary movements, we investigated the electromyography signals of six muscles in a non-dominant upper limb during fast spiral movement in a horizontal plane; we focused on the muscle synergies and concomitant virtual trajectory. Muscle synergy analysis was performed for three healthy subjects before and after voluntary training for eight days. The results revealed that (1) the six muscle activities in a non-dominant upper limb during spiral tracing are explained by three muscle synergies that respectively represent the bases for the radial, angular, and null movements of a hand according to polar coordinates centered on the shoulder; (2) the three muscle synergies bases for movements hardly changed with voluntary training kinematics; and (3) the virtual trajectory drastically changed with motor enhancement, especially in the angular direction. With fast spiral tracing, the virtual trajectory formed a beautiful but slightly distorted spiral curve that rotated in the opposite direction of the kinematic trajectory. This phenomenon may originate from dynamic compensation by the central nervous system. A central factor in motor skill acquisition must be learning a virtual trajectory by considering the dynamic effect of movement especially in the angular direction. Our results imply that virtual trajectories for movements can be learned with invariant bases using polar coordinates, i.e., muscle synergies.

Keywords: Rehabilitation and assistive robotics, Neuro-robotics
Abstract: Rehabilitation robotic plays an important role in therapeutic exercises by combining robots with computer serious games into an attractive therapeutic platform. However, measuring the degree of engagement of the user is not a trivial task. The difficulty of applying question-based techniques, particularly for patients who have the speech capacity compromised due to cerebrovascular accidents, has inspired us to investigate noninvasive and nonverbal techniques aiming to classifying emotions. For this purpose, a supervised artificial neural network interprets facial infrared thermal images of individuals performing rehabilitation robotic therapy integrated with games. A database containing images of 8 users was generated by combining evoked and spontaneous emotional reactions. In total, 2445 facial thermal images with an average of 100 images per person for three categories of emotions (neutral, motivated, overstressed) were classified. Based on confusion matrix analysis, the experimental results correlated very well with manual estimates, producing an overall performance of 92.6%.

Keywords: Rehabilitation and assistive robotics, Locomotion and manipulation in robots and biological systems, Biological systems modeling
Abstract: To understand the impact of implicit auditory perturbations during gait, we used a pacing task that involves the proper timing and synchrony between heel strike and metronome beats. Five individuals performed two different types of tasks presented in the following order: 1) walk on a treadmill while listening to a steady metronome (non-perturbed condition), and 2) walk on a treadmill while listening to the metronome with rhythmic auditory alteration (perturbed condition). We examined the quality of synchronization between heel strike and the metronome beat, the non-synchronous period following perturbation, and the synchronization period. The subjects followed tightly the metronome beats even for changes of less than 10 msec. In addition, we recorded the electromyographic (EMG) activity of selected muscles of the leg and we found the same pattern for the onset and offset of EMG activity. These results indicate an entrainment between the gait cadence and the metronome rhythm in healthy adults and support new therapies to stimulate changes in rhythm and symmetry.

Keywords: Rehabilitation and assistive robotics, Human-machine interaction
Abstract: Since action and perception are tightly coupled and the dysfunction of one of the two channels necessary give rise to different degrees of impairment in the other, we believe that the recovery process would significantly benefit from training protocols able to evaluate and consistently recruit both motor aspects and proprioception concurrently. Therefore, we propose a novel assistive protocol for kinesthetic training of reaching movements that is able to adaptively regulate the level of haptic guidance according to the level of proprioceptive performance along specific directions. Preliminary results show that our adaptive procedure is able to finely tune the level of guidance to the desired level of kinesthetic performance in all the target directions within the duration of the training session. Moreover, the algorithm is able to compensate for perceptual anisotropies that depend on the force direction and its parameters are sensitive to modulations of the kinesthetic sensitivity that may arise as a consequence of practice.

Keywords: Rehabilitation and assistive robotics, Human-machine interaction
Abstract: Functional magnetic resonance imaging is an often adopted tool to study human motor control mechanisms. Highly controlled experiments as required by this form of analysis can be realized with haptic interfaces. Their design is challenging because of strong safety and MR compatibility requirements. Existing MR-compatible haptic interfaces are restricted to maximum three actuated degrees of freedom. We propose an MR-compatible haptic interface with six actuated degrees of freedom to be able to study human brain mechanisms of natural pick-and-place movements including arm transport. In this work, we present its mechanical design, kinematic and dynamic model, as well as report on its model-based characterization. A novel hybrid control scheme for the employed ultrasonic motors is introduced. Preliminary MR compatibility tests based on one complete actuator-sensor module are performed. No measurable noise is found and thus, bidirectional compatibility of the six DoF interface can be expected.

Attachments: Video
Keywords: Surgical navigation and robotics, Image and model-guided interventions
Abstract: We present a method for three dimensional steering of a beveled-tip flexible needle that can be used in medical robotics for percutaneous assistance procedures. The proposed solution is based on the design of a new duty-cycling control strategy that makes possible to control three degrees of freedom (DOFs) of the needle tip. These DOFs correspond to two rotations that are performed around the needle tip lateral axes and one translation along the needle shape axis. This approach has two advantages compared to existing methods. First it does not rely on a trajectory planning and opens therefore numerous closed-loop control scheme possibilities as for example the implementation of the visual servoing framework based on the task function approach. Second, it does not constraint the needle to follow a succession of planar arcs but allows non planar 3D trajectories. Experimental results of a targeting task performed by visual servoing demonstrate the feasibility of this new concept and its robustness to needle kinematic model errors.

Keywords: Surgical navigation and robotics, Locomotion and manipulation in robots and biological systems, Vascular Biomechatronics
Abstract: The quality of contact between the catheter tip and cardiac tissue has been identified as an important factor in the efficacy of the catheter-based cardiac ablation procedures. However, maintaining a constant tip/tissue contact force during the procedure is difficult due to cardiac and respiratory motions. Robotic manipulation of the catheter has the potential to overcome this difficulty and decrease the range of variations in the contact force during the ablation procedure. This paper investigates the possibility of performing motion compensation for conventional steerable ablation catheters using a robotic manipulator. The behavior of such catheters is analyzed in free space as well as in contact with static and moving targets and the limitations in the actuation mechanism are identified. Based on this analysis, a technique for synchronizing the motion of the catheter tip with cardiac motion is proposed. The suggested control system estimates the frequency of the moving target and reshapes the input trajectory accordingly. The performance of the resulting system is evaluated experimentally. The results show that in the experimental setting, the proposed technique reduces the variations in the contact force and noticeably improves the quality of tip/tissue contact.

Keywords: Technology for assisted surgery and diagnosis, Image and model-guided interventions, Surgical navigation and robotics
Abstract: Needle-based procedures are commonly performed for cancer diagnosis and treatment. Imaging modalities are used to visualize the needle tip and the target during these needle insertion procedures. Among the available imaging techniques, magnetic resonance (MR) offers the best tissue contrast, where detection of an early stage cancer is possible. MR-guided needle insertions are currently performed with rigid needles, which have limited steerability. Flexible needles have been introduced to increase the steerability during the insertion. In this paper, we present a preliminary evaluation of a steering method for flexible bevel-tipped needles using MR as an imaging modality. The steering algorithm uses a needle deflection model to predict the tip motion and calculate the optimal rotation to reach the target. The best sequence of rotations are defined by an optimization algorithm based on the Nelder-Mead technique. The needle tip and the target are manually tracked through a graphical user interface. The needle is inserted by a device fabricated with MR-compatible material. The MR-guided flexible needle steering is evaluated by a series of insertions in two phantoms with real obstacles and targets. The average targeting error with flexible needles is 4.3mm, which is 28% lower than the values reported in the literature with rigid needles. The results indicate the feasibility of MR-guided flexible needle insertions.

Keywords: Surgical navigation and robotics, Locomotion and manipulation in robots and biological systems, Image and model-guided interventions
Abstract: A new method for the navigation of therapeutic agents in the vascular network is introduced. This method, dubbed Dipole Field Navigation (DFN), is characterized by high directional gradients and a high magnetic field strength. The latter is used to bring magnetic therapeutic agents at saturation magnetization such that when combined with high directional gradients, effective navigation at any depths within the patient can be achieved. DFN does not have many of the constraints of gradient coil-based platforms, which include potential peripheral nerve stimulations, reduced directional changes and slew rates of the gradient fields, overheating of the coils, and high implementation cost. To achieve such specifications, soft ferromagnetic cores are positioned at specific locations inside the tunnel of a clinical MRI scanner providing a high uniform field of typically up to 3 T, sufficient to bring both the cores and the therapeutic agents at full saturation magnetization. The field distortions created by the cores result in gradients exceeding 300 mT/m for whole body interventions. Hence, with such cores placed at specific locations, the resulting gradients would cause the therapeutic agents to follow a precise path in the vascular network towards the targeted region. In this paper, the fundamental theory of DFN with preliminary in vitro experimental results using one core in a 1.5 T scanner confirms the potential of DFN for targeted drug delivery.

Keywords: Surgical navigation and robotics, Biologically-inspired systems
Abstract: In this paper, statics model of an underactuated wire-driven flexible robotic arm is introduced. The robotic arm is composed of a serpentine backbone and a set of controlling wires. It has decoupled bending rigidity and axial rigidity, which enables the robot large axial payload capacity. Statics model of the robotic arm is developed using the Newton-Euler method. Combined with the kinematics model, the robotic arm deformation as well as the wire motion needed to control the robotic arm can be obtained. The model is validated by experiments. Results show that, the proposed model can well predict the robotic arm bending curve. Also, the bending curve is not affected by the wire pre-tension. This enables the wire-driven robotic arm with potential applications in minimally invasive surgical operations.

Attachments: Video
Keywords: Technology for assisted surgery and diagnosis, Surgical navigation and robotics, Image and model-guided interventions
Abstract: Cochlear implantation requires the placement of an electrode array into the cochlea of patients with severe to profound hearing loss. As the array is placed without direct visualization, robotic guidance has significant potential to improve upon the precision of electrode placement within the cochlea. Here, we evaluate the repeatability of robot-assisted placement of an implant array to an optimal deployment point within a phantom cochlea. This system guides the insertion of the implant by enacting virtual fixtures. When compared to the standard manual method of insertion, we observed a 61.7% reduction in the mean error.

Attachments: Video
Keywords: Surgical navigation and robotics
Abstract: Within robotic-aided laparoscopy, one important research topic concerns the teleoperation of open chain serial link manipulators. As opposed to specialized surgical robots, a serial robot might be used for different procedures with small changes on the setup, lowering the involved costs and possibly increasing the acceptance of robotic systems in clinical settings. However, such robots do not present kinematic constraints that guarantee that the tool movements are projected on the pivoting point defined by the incision (RCM). In such scenario, the RCM must be assured by software. This paper presents a novel control strategy for laparoscopic tools attached to robotic manipulators that makes use of a programmable RCM. The tool movement references are generated intuitively by the surgeon, while the RCM is maintained by software using a dual quaternion-based kinematic controller. The method is evaluated in a simulated surgical environment and presented satisfactory results, both in terms of RCM control, tool positioning, and good performance under human operation.

Attachments: Video
Keywords: Surgical navigation and robotics, Technology for assisted surgery and diagnosis
Abstract: This paper presents a novel control architecture for hybrid stiff and compliant control for minimally invasive surgery which satisfies the constraints of zero lateral velocity at the entry point for serial manipulators. For minimally invasive surgery it is required that there is no sideways motion at the point where the robots enter the abdomen. This is necessary to avoid any damage to the patient's body when the robot moves. We solve this at a kinematic level, i.e., we find a Jacobian matrix that maps the velocities in joint space to the end-effector velocities and at the same time guarantees that certain velocities at the entry point are zero. Because the new velocity variables are defined in the end-effector workspace we can use these for hybrid motion/force control. The approach is verified experimentally by implementing hybrid stiff and compliant control of the end effector and we show that the insertion point constraints are always satisfied.

Keywords: Surgical navigation and robotics, Technology for assisted surgery and diagnosis
Abstract: In this paper a novel telemanipulator system is proposed, able to assist during reconstructive surgery procedures involving microsurgical techniques. The proposed solution is based on maintaining work methods and infrastructure in the operating room (OR). An extensive analysis of these conventional methodologies, combined with a review of currently available alternative solutions, has led to the design of a new 7DOF master-slave system. The modular design concept is focused on precision, safety, ease-of-use, and cost-efficiency. A proof-of-concept has been tested, whereas preliminary results indicate a bidirectional precision at the slave end effector of 70 μm. Through optimization of the control software, a bidirectional precision down to 30-40 μm can be achieved.

Keywords: Technology for assisted surgery and diagnosis, Biomechatronic and human-centred design, Surgical navigation and robotics
Abstract: Minimally invasive surgery (MIS) has proven to be beneficial in providing outstanding results for the patients. However, studies have shown that the surgeon faces significant challenges whilst performing this type of surgery, ranging from poorly designed instrument handles, to potential harm to the surgeon due to awkward postures. Deriving from the crucial need to develop surgical instruments that fully address the needs of the surgeons while applying MIS techniques, a more ergonomic surgical instrument that implements mechatronic characteristics is hereby proposed. This concept instrument is aiming at minimizing post-operation injuries of surgeons and maximizing their kinetic abilities during surgical procedures, whilst also improving speed and accuracy in the performed task.

Keywords: Technology for assisted surgery and diagnosis, Image and model-guided interventions, Rehabilitation and assistive robotics
Abstract: This paper presents a system to supervise tissue temperature during robotic laser surgery. The use of robotic systems for laser surgery provides mechanisms to control the motion of the laser beam and the exposure time of laser radiation, allowing the automatic generation of incisions. This work focuses on the perception side of the problem, developing a technology for the online verification of the thermal state of the tissue during robotic laser microsurgery. Obtaining this information is paramount to enable automatic control of laser incision quality, which is directly related to tissue temperature. A model learned from real data estimates the change in temperature given the exposure time and power of the laser. The model is implemented in the real system and validated during laser incisions on ex-vivo tissue. Results show that the model can reliably estimate the thermal state of the tissue in real-time, and thus is suitable to produce feedback for automatic control of laser incisions.

Attachments: Video
Keywords: Technology for assisted surgery and diagnosis, Biologically-inspired systems, Human-machine interaction
Abstract: Abdominal surgery has seen a rapid transition from open procedures to Robot-Assisted Minimally Invasive Surgery (R-A MIS). The learning process for new surgeons is long compared to open surgery, and the desired dexterity cannot always be achieved using the current surgical instruments. Furthermore, the way that these instruments are controlled plays an important role in their effectiveness and the ergonomics of the procedure. This paper presents the microAngelo Surgical System for R-A abdominal MIS, based on an anthropomorphic design comprising two three-digit surgical instruments and a sensory hand exoskeleton. The operation of these subsystems and the efficacy of their corresponding performance are demonstrated.