Laura Santos-Carreras

Survey on Surgical Instrument Handle Design: Ergonomics and Acceptance

Minimally invasive surgical approaches have revolutionized surgical care and considerably improved surgical outcomes. The instrumentation has changed significantly from open to laparoscopic and robotic surgery with various usability and ergonomics qualities. To establish guidelines for future designing of surgical instruments, this study assesses the effects of current surgical approaches and instruments on the surgeon. Furthermore, an analysis of surgeons’ preferences with respect to instrument handles was performed to identify the main acceptance criteria. In all, 49 surgeons (24 with robotic surgery experience, 25 without) completed the survey about physical discomfort and working conditions. The respondents evaluated comfort, intuitiveness, precision, and stability of 7 instrument handles. Robotic surgery procedures generally take a longer time than conventional procedures but result in less back, shoulder, and wrist pain; 28% of surgeons complained about finger and neck pain during robotic surgery. Three handles (conventional needle holder, da Vinci wrist, and joystick-like handle) received significantly higher scores for most of the proposed criteria. The handle preference is best explained by a regression model related only to comfort and precision (R2 = 0.91) and is significantly affected by the surgeon’s background (P < .001). Although robotic surgery seems to alleviate physical discomfort during and after surgery, the results of this study show that there is room for improvement in the sitting posture and in the ergonomics of the handles. Comfort and precision have been found to be the most important aspects for the surgeon’s choice of an instrument handle. Furthermore, surgeons’ professional background should be considered when designing novel surgical instruments.

Augmented white cane with multimodal haptic feedback

This paper proposes an instrumented handle with multimodal augmented haptic feedback, which can be integrated into a conventional white cane to extend the haptic exploration range of visually impaired users. The information extracted from the environment through a hybrid range sensor is conveyed to the user in an intuitive manner over two haptic feedback systems. The first renders impulses that imitate the impact of the real cane with a distant obstacle. In combination with the range sensors, this system allows to “touch” and explore remote objects, thus compensating for the limited range of the conventional white cane without altering its intuitive usage. The impulses are generated by storing kinetic energy in a spinning inertia wheel, which is released by abruptly braking the wheel. Furthermore, a vibrotactile interface integrated into the ergonomic handle conveys the distance to obstacles to the user. Three vibrating motors located along the index finger and hand are activated in different spatiotemporal patterns to induce a sense of distance through apparent movement. The realized augmented white cane not only increases the safety of the user by detecting obstacles from a further distance and alerting about those located at the head level, but also allows the user to build extended spatial mental models by increasing the sensing range, thereby allowing anticipated decision making and thus more natural navigation.

Towards multimodal haptics for teleoperation: Design of a tactile thermal display

Surgical robotics is among the most challenging applications of motion control. Present and future systems are essentially master-slave systems. Our work focuses on force-feedback and haptic interfaces. In this context, we study multimodal haptic interfaces, i.e. the fusion of force-feedback, with other tactile information such as temperature or pressure. First results support the proposition that such multimodal haptic devices can help improve surgeons dexterity and motion control. In order to strengthen this point, we investigate the psychophysics of thermal perception. This paper presents a device for temperature feedback that can be integrated in a multimodal haptic console. A finger sized tactile temperature display able to generate temperature gradients under the fingertip is presented along with first measurement results.

Design and psychophysical evaluation of a tactile pulse display for teleoperated artery palpation

During traditional open procedures, surgeons directly palpate tissues before dissecting them. In this way, they can avoid the accidental damage of hidden arteries that can lead to fatal hemorrhage. New Minimally Invasive Surgical (MIS) techniques progressively decreased the instrument access into the patients body to reduce scars and side effects. The major drawback of these procedures is that they do not permit surgeons to perform direct tactile exploration of internal tissues. Surgeons have to rely on preoperative images and anatomical knowledge to avoid artery locations. However, the exact artery position changes depending on the patient and his posture. Hence, it is of primary importance to assist surgeons with technology that can guide them during the surgical procedure. This paper presents the design and evaluation of a tactile display that reproduces pulse-like feedback on the surgeons fingertip. The display bandwidth and performance of the ad-hoc control unit were assessed with encouraging results. In addition, the outcome of two psychophysical studies carried out in this work validate the usability of the display in terms of user perception.

Influence of force and torque feedback on operator performance in a VR-based suturing task

The introduction of Minimally Invasive Surgery MIS has revolutionised surgical care, considerably improving the quality of many surgical procedures. Technological advances, particularly in robotic surgery systems, have reduced the complexity of such an approach, paving the way for even less invasive surgical trends. However, the fact that haptic feedback has been progressively lost through this transition is an issue that to date has not been solved. Whereas traditional open surgery provides full haptic feedback, the introduction of MIS has eliminated the possibility of direct palpation and tactile exploration. Nevertheless, these procedures still provide a certain amount of force feedback through the rigid laparoscopic tool. Many of the current telemanipulated robotic surgical systems in return do not provide full haptic feedback, which to a certain extent can be explained by the requirement of force sensors integrated into the tools of the slave robot and actuators in the surgeons master console. In view of the increased complexity and cost, the benefit of haptic feedback is open to dispute. Nevertheless, studies have shown the importance of haptic feedback, especially when visual feedback is unreliable or absent. In order to explore the importance of haptic feedback for the surgeons master console of a novel teleoperated robotic surgical system, we have identified a typical surgical task where performance could potentially be improved by haptic feedback, and investigate performance with and without this feedback. Two rounds of experiments are performed with 10 subjects, six of them with a medical background. Results show that feedback conditions, including force feedback, significantly improve task performance independently of the operators suturing experience. There is, however, no further significant improvement when torque feedback is added. Consequently, it is deduced that force feedback in translations improves subjects dexterity, while torque feedback might not further benefit such a task.

Combined tendon vibration and virtual reality for post-stroke hand rehabilitation

Sensory function is essential for functional post-stroke recovery and control of basic hand movements like grasping. Despite this fact, therapy focuses strongly on motor aspects of rehabilitation, requiring active participation and thus excluding stroke patients with severe paresis. The aim of our novel therapeutic approach combining virtual reality, based on clinically proven mirror therapy, and tendon vibration of hand and wrist muscles is to induce neuroplastic changes leading to improved hand function. This paper presents the further development and evaluation of a robotic device, which can apply vibrations at precise locations on the finger flexor tendons to create illusions of extension movements and visualize the movements with a virtual hand. A preliminary study including 16 healthy subjects investigated the influence of the virtual reality on the perception of proprioceptive illusory movements. The experimental results provided evidence that the addition of the virtual reality enhanced the perception of the illusory movement generated by tendon vibration, by inducing movements with significantly higher extension (+4.5%, p <; 0.05). Furthermore, the virtual reality allowed a better controlled temporal elicitation of the illusion. These findings indicate the potential of this novel strategy for a more effective therapy, especially for severely impaired patients.

Dionis: A novel remote-center-of-motion parallel manipulator for Minimally Invasive Surgery

The large volume and reduced dexterity of current surgical robotic systems are factors that restrict their effective performance. To improve the usefulness of surgical robots in minimally invasive surgery MIS, a compact and accurate positioning mechanism, named Dionis, is proposed in this paper. This spatial hybrid mechanism based on a novel parallel kinematics is able to provide three rotations and one translation for single port procedures. The corresponding axes intersect at a remote center of rotation RCM that is the MIS entry port. Another important feature of the proposed positioning manipulator is that it can be placed below the operating table plane, allowing a quick and direct access to the patient, without removing the robotic system. This, besides saving precious space in the operating room, may improve safety over existing solutions. The conceptual design of Dionis is presented in this paper. Solutions for the inverse and direct kinematics are developed, as well as the analytical workspace and singularity analysis. Due to its unique design and kinematics, the proposed mechanism is highly compact, stiff and its dexterity fullfils the workspace specifications for MIS procedures.

Multimodal haptic interface for surgical robotics

The coming years will see a rapid development of telemanipulators for robotic surgery. These systems will open up new possibilities in surgery. Patient safety and acceptance among surgeons are two key issues in this context. We believe that haptic feedback at the console will be an essential feature for both, increased safety and acceptance among surgeons. We aim at giving the surgeon the feeling that he or she is directly operating with his/her own hands on the patients body. For this, multimodal haptic feedback will be necessary, i.e. the merging of force-feedback, temperature sensing, pressure sensing, and texture rendering, in addition to an ergonomic design of the console itself. We will present some preliminary designs of such systems which are currently being developed in the framework of several projects.

Encoded and Crossmodal Thermal Stimulation through a Fingertip-Sized Haptic Display

Haptic displays aim at artificially creating tactile sensations by applying tactile features to the user’s skin. Although thermal perception is a haptic modality it has received scant attention possibly because humans process thermal properties of objects slower than other tactile properties. Yet, thermal feedback is important for material discrimination and has been used to convey thermally-encoded information in environments in which vibrotactile feedback might be masked by noise and/or movements. Moreover, the well-reported influence of temperature over tactile processing makes thermal displays good candidates for the development of crossmodal haptic interfaces, in which temperature is used to manipulate other sensations. Here, we present a thermal display able to render four individually-controlled temperatures at the user’s fingertip along with its technical characterization and psychophysical evaluation. Device performance was assessed in terms of accuracy and repeatability. In the psychophysical evaluation, we first show that the device can render perceivable temperature gradients at the level of the fingertip, thereby extending the concept of thermally-encoded information to fingertip-sized thermal displays. Secondly, we show that increasing temperature improves stiffness precision. Results show that neglected features of thermal feedback, i.e. encoded and crossmodal thermal stimulation, can be provided by fingertip-sized thermal displays to improve haptic manipulations.

Tactile Feedback Improves Performance in a Palpation Task: Results in a VR-Based Testbed

Robotic surgery provides many benefits such as reduced invasiveness and increased dexterity. This comes at the cost of no direct contact between surgeon and patient. This physical separation prevents surgeons from performing direct haptic exploration of tissues and organs, imposing exclusive reliance on visual cues. Current technology is not yet able to both measure and reproduce a realistic and complete sense of touch (interaction force, temperature, roughness, etc.). In this paper, we put forward a concept based on multimodal feedback consisting of the integration of different kinds of visual and tactile cues with force feedback that can potentially improve both the surgeons performance and the patients safety. We present a cost-effective tactile display simulating a pulsating artery that has been integrated into a haptic workstation to combine both tactile and force-feedback information. Furthermore, we investigate the effect of different feedback types, including tactile and/or visual cues, on the performance of subjects carrying out two typical palpation tasks: (1) exploring a tissue to find a hidden artery and (2) identifying the orientation of a hidden artery. The results show that adding tactile feedback significantly reduces task completion time. Moreover, for high difficulty levels, subjects perform better with the feedback condition combining tactile and visual cues. As a matter of fact, the majority of the subjects in the study preferred this combined feedback because redundant feedback reassures subjects in their actions. Based on this work, we can infer that multimodal haptic feedback improves subjects performance and confidence during exploratory procedures.