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A Modular, Automated Laparoscopic Grasper with Three-Dimensional Force Measurement Capability
Abstract
The introduction of robot-assisted surgery into the operating room has led to significant improvements in surgical procedures. However, the lack of haptic feedback in these robotic systems using long teleoperated instruments has negatively affected the surgeon's ability to palpate tissue and diagnose it as healthy or unhealthy. This paper describes our design of a modular, automated laparoscopic grasper with tri-directional force measurement capability. The grasper can measure normal grasping forces, as well as, sideways manipulation forces during grasping and palpation tasks. Additionally, a modular design allows for easy conversion between surgical modalities (e.g., grasping, cutting, and dissecting). Calibration of the force sensors and initial testing of the prototype has shown its ability to accurately measure tool-tissue interaction forces.
... The gripping force measurements could be used to offer tactile feedback to the user, in addition to the visual one offered in the developed graphical interface. In literature, the importance of this feedback is reported during the training process [59]. For the development of this feature the design and implementation of a different tool handle and a mechanic grasping system, which emulated the force interaction at the tip would be needed. ...
... The proposed force training module helps surgeons distinguish among samples with different stiffness. The use of phantoms with a difference in stiffness was seen in previous work [59], which detected it by correlating the gripping force and the closing-angle of the tip. Nevertheless, herein we propose the concept of measuring the force from an outer-tool component with the instrumentation of phantoms themselves. ...
... The "current study" refers to the cost of our simulator components (not including the standard laparoscopic surgery instruments). We considered the commercial systems Lap-X (Medical X, Rotterdam, The Netherlands) and LaPlay (Jinan One Half Industrial Design, Shandong, China) box trainers with haptic force feedback and no force feedback, respectively; as well as a proposal from Tavakoli et al., a system based in photonic crystal fiber sensor; proposals of Barrie et al. and Hannah et al., both based on force sensing at the handle; and Tholey's proposal, with the grasper-tip instrumented and hydrogel phantoms [13,14,53,59,61,62]. Moreover, some researchers employ specialized and costly devices to measure the position and orientation of the laparoscopic instrument. ...
Laparoscopic surgery demands highly skilled surgeons. Traditionally, a surgeon’s knowledge is acquired by operating under a mentor-trainee method. In recent years, laparoscopic simulators have gained ground as tools in skill acquisition. Despite the wide range of laparoscopic simulators available, few provide objective feedback to the trainee. Those systems with quantitative feedback tend to be high-end solutions with limited availability due to cost. A modular smart trainer was developed, combining tool-tracking and force-using employing commercially available sensors. Additionally, a force training system based on polydimethylsiloxane (PDMS) phantoms for sample stiffness differentiation is presented. This prototype was tested with 39 subjects, between novices (13), intermediates (13), and experts (13), evaluating execution differences among groups in training exercises. The estimated cost is USD $200 (components only), not including laparoscopic instruments. The motion system was tested for noise reduction and position validation with a mean error of 0.94 mm. Grasping force approximation showed a correlation of 0.9975. Furthermore, differences in phantoms stiffness effectively reflected user manipulation. Subject groups showed significant differences in execution time, accumulated distance, and mean and maximum applied grasping force. Accurate information was obtained regarding motion and force. The developed force-sensing tool can easily be transferred to a clinical setting. Further work will consist on a validation of the simulator on a wider range of tasks and a larger sample of volunteers.
... However, the high stiffness characteristics of the Stewart platform type parallel structure may lower the measurement sensitivity, and the grasp force cannot be sensed from this approach. In [20], four strain gauges were used to sense sideways manipulation forces acting at the forceps, and for the measure of grasp force, one resistive sensor was mounted in one of the forceps. However, the significant hysteresis and nonlinear characteristics of the resistive sensor have been reported in this work. ...
... From the measured values of the bending strains ε i 's, the torque changes δτ i 's of the hinge joints are found from (15). Then, the pulling and grasp forces δf t and δf n acting at the tip of the forceps are computed from (20). It is noted, here, that δf t and δf n are the changes of the transversal pulling and normal grasp forces at the instant under consideration. ...
... Using the dishes having 17.88 g of the mass, weights are applied, respectively, to the tip of a forcep in 5-g increments from 0 to 100 g and 50-g increments from 100 to 450 g to each direction of the x-and y-axes. When a weight is applied to the tip, the transversal pulling and normal grasp forces f t and f n are found from the measured bending strains and (20). Then from Fig. 6(b), the x-and y-directional forces f x,m and f y ,m can be obtained as f x,m = −f t C θ + f n S θ and f y ,m = −f t S θ − f n C θ . ...
In this paper, a novel concept of two-degree-of-freedom (2-DOF) compliant forceps is suggested for the measure of pulling and grasp forces at the tip of surgical instrument for minimally invasive surgery robot. For the design of the compliant forceps, the required compliance characteristics are first defined using a simple spring model with one linear and one torsional springs. This model may be directly realized as the compliant forceps. However, for the compact realization of the mechanism, we synthesize the spring model with two torsional springs that has equivalent compliance characteristics to the linear-torsional spring model. Then, each of the synthesized torsional springs is realized physically by means of a flexure hinge. From this design approach, direct measurement of the pulling and grasp forces is possible at the forceps, and measuring sensitivity can be adjusted in the synthesis process. The validity of the design is evaluated by finite element analysis. Further, from the measured values of bending strains of two flexure hinges, a method to compute the decoupled pulling and grasp forces is presented via the theory of screws. Finally, force-sensing performance of the proposed compliant forceps is verified from the experiments of the prototype using some weights and load cells.
... One possible classification is by the sensing principle. Most of the sensors utilize piezoresistive principle by doping strain gauges in single crystal Si [7][8][9][10][11][12][13][14][15][16][17]. This method is convenient because of the high gauge factor of silicon (about 200-300) and the ability to implement the sensor into a Si structure of a bridge's plate. ...
... The sensors also differ by the scale of their sensing range. At the high end, sensors for robotics and MIRS can sense 5-30 N [14,18,22,26]. The commercial 6 DoF force/torque sensor of ATI Industrial Automation known as Nano-17 having a size of Ø17 mm and height of 14.5 mm also belongs to this category. ...
... One can also distinguish between micro fabrication technologies, e.g. MEMS technologies, [7][8][9][10][11][12][13][15][16][17]24,25] and standard precision or electrical discharge machining (EDM) [14,[18][19][20][21][22][23]26] in Table 1. Despite the tendency of making the MEMS sensors smaller, the packaged sensors do not differ much in size from other sensors. ...
A novel, robust, tri-axial force sensor has been developed that can be integrated into biomedical and robotic devices thanks to its size and accuracy. It features a titanium alloy body, the components of the force are separated by four basic strain sensing elements. The sensor was modeled by finite element method and the results were validated by experimental data. The sensor's diameter is 2.6 mm, its height is 2 mm. Proper signal conditioning tools were realized in software and hardware to achieve a sensitivity of 29.63 mV/N and minimum detectable force of 4.87 mN. The sensing element's structure fits electrical discharge machining technologies. The sensor was calibrated with a Nano 17 force sensor and we found that its performance is comparable to the commercial device.
... On the other hand, sensor designs for surgical application have also been investigated, as force sensation offers several advantages for robotic surgery, such as injury reduction [31] and enabling palpation [32]. Force sensors based on different transducer technologies have been proposed, including magnetic [32], optical [33]- [36], resistive [27], [37], [38] and capacitive [39]- [41]. These sensors have been integrated to either conventional two-jawed graspers [36], [38], [39], [41], [42], or specially-designed palpation tools [32], [33], [35], [40] that need to be interchanged during surgery. ...
... Force sensors based on different transducer technologies have been proposed, including magnetic [32], optical [33]- [36], resistive [27], [37], [38] and capacitive [39]- [41]. These sensors have been integrated to either conventional two-jawed graspers [36], [38], [39], [41], [42], or specially-designed palpation tools [32], [33], [35], [40] that need to be interchanged during surgery. ...
Although substantial progresses have been made in robot-assisted laparoscopic surgery, the graspers for existing surgical systems generally remain non-sensorized forceps design with limited functions. This paper presents the design, development and preliminary evaluation of the MUSHA Hand II, a multifunctional hand with force sensors for robot-assisted laparoscopic surgery. The proposed hand has three snake-like underactuated fingers that can be folded into a 12 mm cylindrical form. Each finger has a three-axis force sensor, to provide force information. After been deployed into an abdominal cavity, the hand can be configured to either grasper mode, retractor mode or palpation mode for different tasks. Underactuated finger design enhances the adaptivity in grasping and the compliance in interaction with the environment. In addition, fingertip force sensors can be utilized for palpation to obtain a real-time stiffness map of organs. Using the da Vinci Research Kit (dVRK) as a robotic testbed, the functionality of the hand has been demonstrated and experiments have been conducted, including robotic palpation and organ manipulation. The results suggest that the hand can effectively enhance the functionality of a robotic surgical system and overcome the limits on force sensing introduced by the use of robots in laparoscopic surgery.
... Various force information technologies have been proposed to solve the problem of lack of force information in minimally invasive surgery. (16)(17)(18) For example, the force measurement range for robotic forceps grippers is 0.5 to 10 N. The force measurement range with a catheter insertion robot, such as for ablation, is generally 0 to 0.5 N. In addition, sensor-integrated tools have been designed, such as force-sensing forceps, (19,20) force-controlled grippers, (17,21,22) and sensorintegrated scalpels. (23,24) For example, Tanimoto et al. (25) proposed a small-diameter force sensor using strain gauges for a catheter surgery robot. ...
... With built-in features including increased range of motion, tremor filters, motion scaling, virtual fixtures, position precision and accuracy, robot-assisted surgery promises technical skill and dexterity in surgery, not previously possible [7][8][9][10]. In tele-robotic surgery, haptic feedback as a sense of touch [11] has been demonstrated to improve task performance relative to the forces applied [12], accuracy [13,14], and tissue characterization [15], thus providing increased levels of surgical precision. Furthermore, by creating a digital footprint of surgery through recording the quantifiable dexterity of surgeons and task specifications, robotic technology allows standardization of surgical procedures and performance. ...
Objectives: With the increase in robot-assisted cases, recording the quantifiable dexterity of surgeons is essential for proficiency evaluations. The present study employs sensor-based kinematics and recorded surgeon experience for evaluating a new haptic device.
Methods: Thirty surgeons performed a task simulating micromanipulation with neuroArmPLUSHD and two commercially available hand-controllers. The surgical performance was evaluated based on subjective measures obtained from survey and objective features derived from the sensors. Statistical analyses were performed to assess the hand-controllers and regression analysis was used to identify the key features and develop a machine learning model for surgical skill assessment.
Findings: MANCOVA tests on objective features demonstrated significance (= 0.05) for time (p = 0.02), errors (p = 0.01), distance (p = 0.03), clutch incidents (p = 0.03) and forces (p = 0.00). The majority of metrics were in favor of neuroArmPLUSHD. The surgeons found it smoother, more comfortable, less tiring and easier to maneuver with more realistic force feedback. The ensemble machine learning model trained with 5-fold cross-validation showed an accuracy (SD) of 0.78 (0.15) in surgeon skill classification.
Conclusions: This study validates the importance of incorporating a superior haptic device in telerobotic surgery for standardization of surgical education and patient care.
Our documented data management and analytics platform is provided in the link below: https://amirbgithub.github.io/smart-handcontroller/
... Thereby facilitating the clinicians with a digital display of the profile sensed. Endoscopic graspers based on several working principles such as piezoelectric (Dargahi et al., 2000), piezoresistive (King et al., 2009;Kuwana et al., 2013;Valdastri et al., 2006), strain gauge (Hagn et al., 2010;Hong and Jo, 2012;Tholey and Desai, 2007) and acoustic reflection (Ly et al., 2017) (Fig. 5d), has been designed to characterize the tissue sample as hard, medium or soft. Each sensing element in the array has to be calibrated accurately such that the overall sensitivity of the array is not compromised. ...
From cancer diagnosis to detailed characterization of arterial wall biomechanics, the elastic property of tissues is widely studied as an early sign of disease onset. The fibrous structural features of tissues are a direct measure of its health and functionality. Alterations in the structural features of tissues are often manifested as local stiffening and are early signs for diagnosing a disease. These elastic properties are measured ex vivo in conventional mechanical testing regimes, however, the heterogeneous microstructure of tissues can be accurately resolved over relatively smaller length scales with enhanced spatial resolution using techniques such as micro-indentation, microelectromechanical (MEMS) based cantilever sensors and optical catheters which also facilitate in vivo assessment of mechanical properties. In this review, we describe several probing strategies (qualitative and quantitative) based on the spatial scale of mechanical assessment and also discuss the potential use of machine learning techniques to compute the mechanical properties of soft tissues. This work details state of the art advancement in probing strategies, associated challenges toward quantitative characterization of tissue biomechanics both from an engineering and clinical standpoint.
... Lastly, it is not economical to use the comparatively expensive force sensors for instruments due to their limited working life about 10 times. To solve this problem, some sensors are designed to attach to instrument shaft [24][25][26], articulated joint [27], trocar [2,28] and joint actuation unit [29]. However, the sensors may provide inaccurate force information due to variations of nonlinear friction, hysteresis, inertia and gravity. ...
Due to the narrow space and a harsh chemical environment in the sterilization processes for the end-effector of surgical robots, it is difficult to install and integrate suitable sensors for the purpose of effective and precise force control. This paper presents an innovative tension sensor for estimation of grasping force in our laparoscope surgical robot. The proposed sensor measures the tension of cable using fiber gratings (FBGs) which are pasted in the grooves on the inclined cantilevers of the sensor. By exploiting the stain measurement characteristics of FBGs, the small deformation of the inclined cantilevers caused by the cable tension can be measured. The working principle and the sensor model are analyzed. Based on the sensor model, the dimensions of the sensor are designed and optimized. A dedicated experimental setup is established to calibrate and test the sensor. The results of experiments for estimation the grasping force validate the sensor.
... As an alternative to expensive tool-tip force sensors, other researchers have tried to estimate tool-tip forces by monitoring actuator effort. This can be achieved via measurements of motor current (82), strain gauges (77,83,84), pneumatic pressure (72), and joint actuator forces (52,85), with the potential to reduce noise via dithering (55, 86). ...
Emerging paradigms furthering the reach of medical technology into human anatomy present unique modeling, control, and sensing problems. This review provides a brief history of medical robotics, leading to the current trend of minimally invasive intervention and diagnostics in confined spaces. We discuss robotics for natural orifice and single-port access surgery, capsule and magnetically actuated robotics, and microrobotics, with the aim of elucidating the state of the art. We also discuss works on modeling, sensing, and control of mechanical architectures of robots for natural orifice and single-port access surgery, followed by works on magnetic actuation, sensing, and localization for capsule robotics and microrobotics. Finally, we present challenges and open problems in each of these areas. Expected final online publication date for the Annual Review of Control, Robotics, and Autonomous Systems Volume 1 is May 28, 2018. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.
... Besides retrofitting conventional laparoscopic instruments, research efforts have also been conducted in developing automated laparoscopic tools with force measurement capability [16,17]. Most of these tools incorporate the advantage of actuation mechanisms for utilising in robotic surgical systems [18,19]. ...
An automated laparoscopic instrument capable of non-invasive measurement of tip/tissue interaction forces for direct application in robotic assisted minimally invasive surgery systems is introduced in this paper. It has the capability to measure normal grasping forces as well as lateral interaction forces without any sensor mounted on the tip jaws. Further to non-invasive actuation of the tip, the proposed instrument is also able to change the grasping direction during surgical operation. Modular design of the instrument allows conversion between surgical modalities (e.g., grasping, cutting, and dissecting). The main focus of this paper is on evaluation of the grasping force capability of the proposed instrument. The mathematical formulation of fenestrated insert is presented and its non-linear behaviour is studied. In order to measure the stiffness of soft tissues, a device was developed that is also described in this paper. Tissue characterisation experiments were conducted and results are presented and analysed here. The experimental results verify the capability of the proposed instrument in accurately measuring grasping forces and in characterising artificial tissue samples of varying stiffness.
... Various other publications present tactile sensing approaches for MIS [155][156][157][158][159][160][161] -most of them for measuring the elastic properties of tissue -, special control algorithms [162], investigate human finger perception [57,[163][164][165], or draw conclusions on tactile characteristics from special MIS graspers [166][167][168][169][170]. However, none of the found publications focuses on the detection of blood vessels as a central issue or describe an approach comparable to the one proposed in this thesis. ...
In der konventionellen robotergestützten, minimal invasiven Chirurgie (MIC) besteht eine vollständige mechanische Entkopplung zwischen Chirurg und Patient. Die Entwicklung kinästhetischer Rückkopplungssysteme ist fortgeschritten, die Rückkopplung taktiler Eindrücke ist jedoch nach wie vor problematisch. Es wurden viele Versuche unternommen, vollständige teletaktile Eindrücke zu vermitteln, die jedoch aus unterschiedlichen Gründen scheiterten. Als hauptsächlicher Grund hierfür ist anzusehen, dass die Ausgabeschnittstelle üblicherweise ein eigenständiges Gerät ist, was die gleichzeitige Wahrnehmung von Eindrücken und Steuerung des Instruments erschwert. Die menschliche Wahrnehmung taktiler Eindrücke beruht weitgehend auf dem Betasten des Objekts mit Bewegen des "Sensors", was mit zwei verschiedenen Geräten schwer nachzubilden ist. Außerdem war die Interpretation des rückgekoppelten Signals nicht eindeutig und intuitiv genug.
Eine der größten Schwierigkeiten in der (robotergestützten) minimal invasiven Chirurgie ist die große, durch die fehlende taktile Rückkopplung begründete Gefahr einer unbeabsichtigten Arterienverletzung mit der Folge schwer kontrollierbarer Blutungen. In der offenen Chirurgie kann Gewebe betastet werden, und ein Pulsieren deutet auf eine im Gewebe liegende Arterie hin. Eine Substitution des Tastsinns wäre aber auch aus anderen Gründen wünschenswert. So können in der offenen Herzchirurgie die präoperativ geplanten Anastomosestellen durch Betasten aufgefunden werden. Stehen jedoch nur optische Untersuchungsmethoden zur Verfügung, kann ein sehr zeitaufwendiges Freipräparieren der Arterien notwendig werden, um die präoperativ geplanten Anastomosestellen aufzufinden.
Die in dieser Arbeit vorgeschlagene Lösung bietet keine umfassende taktile Rückkopplung, sondern konzentriert sich auf das ultraschallgestützte, quasi taktile Lokalisieren besonderer Strukturen unter verdeckendem Gewebe. Mit den erfassten Daten erfolgt eine Modalitätssubstitution, dem Nutzer werden intuitive haptische bzw. Mehrkanalinformationen zurückgegeben. Um die Doppler-Frequenzverschiebung des in den betreffenden Arterien fließenden Blutes zu erkennen, wird ein Ultraschalltransducer verwendet, der in ein minimal invasives Instrument integriert ist. Die gemessenen Signale werden analysiert und an ein haptisches Eingabegerät weitergeleitet, mit dem die Erkennung und die Eigenschaften der verdeckten Gefäße intuitiv erfassbar dargestellt werden. Erste Versuche zeigten, dass ein leichtes Zucken des Eingabegerätes in Verbindung mit dem typischen Doppler-Geräusch das direkte Betasten sehr zuverlässig und intuitiv ersetzen. Weiterführende Untersuchungen, die die Verlässlichkeit bestätigen und zu einem tieferen Verständnis dieser Ergebnisse führen sollen, stehen noch aus.
Es ist sehr fraglich, ob eine vollständige Rückkopplung aller möglichen taktilen Eindrücke in der robotergestützten MIC erstrebenswert ist der medizinische Nutzen scheint die Anstrengungen und Kosten nicht zu rechtfertigen. Deshalb verspricht, wie in dieser Arbeit, der Ersatz nur von Teilen der Taktilität, der mit der menschlichen Wahrnehmung vergleichbar ist, eine bessere Lösung zu sein. Im Gegensatz zu in der Literatur beschriebenen Realisierungen, die sich im praktischen Einsatz nicht durchgesetzt haben, hat das hier beschriebene System erste Tests bestanden und seine überlegene Leistungsfähigkeit bewiesen. Ein Patent hierzu wurde bereits erteilt.
... To precisely control the grasp force, however, the instrument must be capable of sensing forces. Several types of force-sensing instruments have been developed by many research groups [14], [41], [44]- [49]. Further in [50], a haptic device with force and thermal feedback was introduced. ...
This paper presents a new type of 4-degree-of-freedom (DOF) robotic surgical instrument for a minimally invasive surgical robot system. The forceps wrist mechanism was designed here on the basis of the 3-DOF parallel structure with three prismatic--spherical--revolute kinematic chains. The pitch and yaw motions of the moving platform generated the wrist rotational motions of the forceps. The axial translation of the parallel mechanism was converted into the forceps grasp motion by an inversion of the slider-crank mechanism. Furthermore, for a more dexterous movement of the forceps, a full revolution of the forceps for the axial rotation is also possible with the instrument. While the proposed instrument realized all the required DOFs of a forceps, the parallel structure of the wrist and the driving mechanism that was designed using only rod elements made the proposed instrument more reliable and rigid than other wire-driven instruments. The kinematic constraints and inverse kinematics of the proposed instrument were derived. Furthermore, the screw-based Jacobian was formulated geometrically, and the static force relation and the linear constraints on a twist were derived. Finally, a prototype of the proposed instrument with a diameter of $hbox{8 mm}$ was introduced, and the performance of the prototype was verified through several experiments.
... To solve the problem concerning the lack of force sensing information in MIS, various force sensing techniques have been proposed [8]- [10]. Sensor-integrated tools have also been designed accordingly such as force sensitive forceps [11]- [13], sensorized graspers [9], [14], [15], and sensor-integrated scalpels [16], [17]. However, there are limitations in the applicability of these devices regarding the sensing capacity, accuracy, cost, size, sterilizability, disposability, and compatibility with other medical appliances (e.g., magnetic resonance imaging (MRI) equipment) [8]. ...
Minimally invasive surgery (MIS) is a surgical technique that offers distinct advantages in reducing pain and patients’ recovery time. However, the drawback due to the lack of force and tactile feedback presents a great deal of limitations in MIS procedures. Tissue palpation, which is easily conducted during traditional open surgery to examine tissue properties and abnormalities, is not possible when performing surgery in a minimally invasive manner. This paper proposes a specially designed miniature 3-axis distal force sensor that can be used to perform tissue palpation, measuring tissue interaction forces at the tip of a surgical instrument. Relying on an optical sensing scheme, the sensor can measure forces within measurement ranges of ±3 N in axial direction and ±1.5 N in radial direction. The resolution is 0.02 N. It is compatible with laparoscopic operations and can be used to localize tissue lesions or relatively hard nodules buried under an organ's surface, which are not detectable by visual means.
... Thielmann et al. [18] have detected gripping and manipulation forces greater than 10 N using a 7 degree-of-freedom (DoF) force/torque sensor in versatile instruments for robotic surgery. Tholey et al. [19] developed disposable forceps capable of measuring force with strain gauges. Hashiguchi et al. [20] developed a force estimation method by monitoring the pressure of pneumatic actuators in a pneumatically driven forceps manipulator. ...
Purpose:
For the application of less invasive robotic neurosurgery to the resection of deep-seated tumors, a prototype system of a force-detecting gripper with a flexible micromanipulator and force feedback to the operating unit will be developed.
Methods:
Gripping force applied on the gripper is detected by strain gauges attached to the gripper clip. The signal is transmitted to the amplifier by wires running through the inner tube of the manipulator. Proportional force is applied on the finger lever of the operating unit by the surgeon using a bilateral control program. A pulling force experienced by the gripper is also detected at the gripper clip. The signal for the pulling force is transmitted in a manner identical to that mentioned previously, and the proportional torque is applied on the touching roller of the finger lever of the operating unit. The surgeon can feel the gripping force as the resistance of the operating force of the finger and can feel the pulling force as the friction at the finger surface.
Results:
A basic operation test showed that both the gripping force and pulling force were clearly detected in the gripping of soft material and that the operator could feel the gripping force and pulling force at the finger lever of the operating unit.
Conclusions:
A prototype of the force feedback in the microgripping manipulator system has been developed. The system will be useful for removing deep-seated brain tumors in future master-slave-type robotic neurosurgery.
... Approaches have mainly centered on adding force sensing capabilities to existing tool structures, where one or two rigid jaws pivot around a central point (as inFigure 1). Such force sensing is commonly performed on some area of tool shaft [8][9] and / or the gripping jaws [10]. Alternatively, [11] and [7] both performed remote tactile object exploration using force-sensing industrial scale robot manipulators to position a tactile array about a compliant object. ...
A natural extension of current robotic minimally invasive surgery (MIS) is the addition of tactile and kinesthetic feedback, which would give an operating surgeon valuable haptic infonnation
about tissue under observation. Identification of haptic properties requires active exploration [1][2]. It is believed that such exploration may be facilitated by a tool capable of replicating the major exploratory procedures (EPs; haptic information gleaning maneuvers) of a surgeon. Such a tool must also fit within the
fabrication and other constraints of similar MIS tools.
In this paper the requirements of such a gripper are highlighted via experiments with surgeons. The results have been used to develop a 2-finger, 3dof (degree of freedom) gripper based on an inverted closed chain serial manipulator. A primary advantage of this system is its dexterity and compactness, compared to other
manipulators. The gripper is shown to be capable of replicating the most frequently observed two-finger exploratory procedures. It is argued that a single tactile sensor is sufficiently useful for a two fingered system and a scaled prototype of the system has been designed to accommodate such a sensor. This system has been designed with later laparoscopic grade manufacture in mind.
... In this regard due to their extra length, conventional motorized systems are not suitable to be used in such grippers. There had been several models designed for such endoscopic gripper [3][4][5][6][7]. It is notable that in medical operations, surgeon must avoid abrupt actuation of the tools [2]. ...
Application of robotic instruments in minimally invasive surgery (MIS) has been developing in recent years. The urge to implement biocompatible and less invasive devices found way in use of materials like shape memory alloys. However such designs presented the idea of using heat control actuation in the MIS surgery and some have found noticeable position in robotic surgery. Yet the problems relating to insufficient stroke, slow motion and unfavorable generated heat have to be defeated. In this work it is focused to overcome these problems by a new design. Modern SMA grippers take advantage of two techniques: Net SMA and Spiral SMA. Both of these actuators demand application of high electric power to raise the wire temperature, which consequently is accompanied by heating of the gripper, slow actuation, etc. While in this paper, we propose the use of one SMA braided-wire in a spiral sheath cut inside the covering tube capable of using longer SMA wire. The outer diameter of the gripper is 3 mm with the total length of 9.5 mm. It demands less electric pulses to actuate, easily controlled and is applicable in heart surgeries with limited trocar aperture. The other design features together with the complete simulation of the device are addressed in the article. A full scale prototype of this SMA gripper capable of using in operation room will be produced by the end of year 2012.
... Research is ongoing into the use of strain/force sensors for the measurement of interaction forces at the instrument-tissue interface. Resistive strain gauge technology has been utilized either in the form of a modular sensor [2, 3] or attached onto the instrument trocar4567. These arrangements only measure interaction and bending forces on the trocar and do not measure grasping and cutting forces. ...
Sensorized instruments which cater for the measurement of interaction forces during surgical procedures are not available
on current commercial Minimally Invasive Robotic Surgical (MIRS) systems. This paper investigates the effectiveness of advanced
optical sensing technology (Fiber Bragg Grating) as surgical end effector strain/force sensors. The effects of adhesive bonding
layer thickness and length are specifically addressed owing to their importance for effective strain transfer and ensuring
compactness of the resulting sensing arrangement. The strain transfer characteristics of the compound sensing arrangement
are evaluated by the examination of shear transfer through the fiber coating and adhesive layers. Detailed analysis of the
sensing scheme is facilitated through the use of FEA. Validation of the resulting models is achieved through experimentation
carried out on an application-specific evaluation platform. Results show that strain values from an FBG are comparable to
that of an electrical strain gauge sensor.
... Chao-Chieh Lan, Member, IEEE, and Jung-Yuan Wang M force is applied at the slider through an inextensible cable driven by the handles. Alternatively, the cable force may also be provided by a geared motor [11] or a pneumatic cylinder [6]. Fig. 1(b) shows a close view of the jaw mechanism. ...
Force regulation is a challenging task of forceps used for robot-assisted surgical manipulation. To avoid excessive force applied on soft tissues, sophisticated sensors with computerized precise control are often required. Without using additional electronic elements, this paper presents a passive mechanism to maintain a constant contact force between forceps jaw tips and tissues given a pre-specified force magnitude. The mechanism consists of symmetric flexible structures specifically designed to generate a constant torque regardless of input rotation. The constant torque is converted to a constant force through an adjustable lever arm. When the force is further transmitted to jaw tips, it keeps a nearly constant contact force regardless of tissue stiffness and size. After a formulation to find the optimal mechanism configuration, the design is verified by comparing experiment and simulation results. A prototype of the adjustable constant-force forceps is finally illustrated and discussed. The novel forceps is expected to serve as a reliable alternative for robot-assisted surgeries.
This paper presents a force/position detection model based on Fiber Bragg grating (FBG), which has been further combined with the octagonal ring structure as a novel surgical jaw. Specifically, the upper jaw is Force/Position-Jaw (FP-Jaw), which is used for position and force detection, and the lower jaw is utilized for temperature compensation. Then through Ansys finite element simulation software, the structure optimization and harmonic response analysis of the clamp were carried out, and the operating frequency of the surgical clamp was determined to be about 0-640Hz. Finally, Temperature-Compensation-Force/Position Network (T-FPNet) for position/force decoupling is proposed, which can achieve temperature compensation as well. The experimental results clearly demonstrate that the proposed FP-Jaw can be well adapted to the forceps, with the measurement range, the maximum sensitivity, the measurement errors of force and accuracy of position being 0-5 N, 130.25 pm/N, 0.49% and 99%, respectively.
This paper presents a clamping force sensor based on fiber Bragg grating (FBG) to provide interaction force feedback for laparoscopic surgery. The proposed sensor mainly consists of a force-sensitive clamping flexure and a tightly suspended optical fiber with an FBG inscribed. The force-sensitive clamping flexure utilizes a bridge-type structure with an excellent load-bearing capacity and anti-interference ability to linearly convert the vertical force or displacement input exerted on the grasping surface into translational deformation along the flexure central line. The FBG fiber is arranged along the flexure central axis to sense the vertical force-induced horizontal strain. This two-point pasting configuration can achieve a uniform fiber strain distribution and an enhanced sensitivity. This assembly arrangement produces a linear relationship between the applied vertical force and the force-induced horizontal strain value sensed by the FBG. The force sensitivity remains the constant and it less affected by the grasping positions due to the high stiffness and deformation conversion, overcoming the difficulty that the traditional clamping force sensor designs are sensitive to the grasping position due to the variable grasping positions and areas on the soft tissues during clamping. The finite element method (FEM)-based simulation has been utilized for design optimization and performance investigation to guide the sensor design. The simulation sensitivity values have been determined as a close value of 52pm/N regarding the three different grasping positions at middle, left and right parts. The optimized sensor design has been integrated into a manual surgical grasper and achieve experimental sensitivity values of 56.2pm/N, 51.1pm/N and 47.5pm/N for the three different loading positions within 0, 10N. Both dynamic loading experiments and clamping experiments on ex-vivo tissues and in-vivo animal for tissue resection were implemented to validate the effectiveness of the proposed design.
Accurate force measurement during forceps manipulation is expected to have various applications such as surgical technique analysis. The calibration method is important for achieving accurate measurement. Previously, for a force measurable forceps (FMF) with 3 degrees of freedom (DOF), a calibration method using unbiased samples has been proposed. However, the required number of samples increases exponentially as the DOF increases. Here, we proposed a semi-automated sampling system for collecting unbiased samples from a FMF with 4DOF. We conducted a collection of unbiased samples, calibration, and compared the accuracy with the standard calibration method for linear force sensors. Sampling took around 10 seconds on average (n=1535). The accuracy, evaluated by the average error[N], for the unbiased sample calibration method (radial traction: −0.0565±0.0638, axial traction: −1.51±4.32, grip: 0.780±1.00) improved by approximatively two folds compared to the standard method (radial traction: −0.112±0.132, axial traction: −8.60±9.04, grip: −1.17±1.07), with maximum measurement ranges[N]of±2.00 for the traction, and±1.60 for the grip. We conclude that these results show the efficiency and accuracy of the proposed device, when compared to the conventional standard methodology.
Objectives:
To provide a systematic overview of the literature assessing the value of haptic and force feedback in current simulators teaching laparoscopic surgical skills.
Data sources:
The databases of Pubmed, Cochrane, Embase, Web of Science, and Google Scholar were searched to retrieve relevant studies published until January 31st, 2017. The search included laparoscopic surgery, simulation, and haptic or force feedback and all relevant synonyms.
Methods:
Duplicates were removed, and titles and abstracts screened. The remaining articles were subsequently screened full text and included in this review if they followed the inclusion criteria. A total of 2 types of feedback have been analyzed and will be discussed separately: haptic- and force feedback.
Results:
A total of 4023 articles were found, of which 87 could be used in this review. A descriptive analysis of the data is provided. Results of the added value of haptic interface devices in virtual reality are variable. Haptic feedback is most important for more complex tasks. The interface devices do not require the highest level of fidelity. Haptic feedback leads to a shorter learning curve with a steadier upward trend. Concerning force feedback, force parameters are measured through force sensing systems in the instrument and/or the environment. These parameters, especially in combination with motion parameters, provide box trainers with an objective evaluation of laparoscopic skills. Feedback of force-use both real time and postpractice has been shown to improve training.
Conclusions:
Haptic feedback is added to virtual reality simulators to increase the fidelity and thereby improve training effect. Variable results have been found from adding haptic feedback. It is most important for more complex tasks, but results in only minor improvements for novice surgeons. Force parameters and force feedback in box trainers have been shown to improve training results.
In this paper, we described a method of sensorless grip force estimation based on Neural Network (NN) optimized by Genetic Algorithm (GA) to address the gripping force estimation problem of laparoscope surgical robots. The gripping force estimation problem is the key of haptic feedback in Robotic Minimally Invasive Surgeries (RMIS). We verified the proposed method and compared with the grip force estimated by dynamic model. The number of units of hidden layer was optimized so that it made a better fitting performance. The experimental results demonstrated that the proposed method had a good performance for the sensorless grip force estimation, which is well applied to our surgical robots.
This paper describes the design, microfabrication, and characterization of a miniature force sensor for providing tactile feedback in robotic surgical systems. We demonstrate for the first time a microfabricated sensor that can provide triaxial sensing (normal, x-shear, y-shear) in a single sensor element that can be integrated with commercial robotic surgical graspers. Features of this capacitive force sensor include differential sensing in the shear directions as well as a design where all electrical connections are on one side, leaving the backside pristine as the sensing face. The sensor readout is performed by a custom-designed printed circuit board with 24-bit resolution. Experimental results of sensor performance show normal force resolution of 0.055 N, x-shear resolution of 0.25 N, and y-shear resolution of 1.45 N, all of which fall in a range of clinically relevant forces.
Measuring force and displacement in some environments is not a straight forward task. For example, in the presence of flammable materials or when surgery robots are dealing with human body, force and displacement sensors should be redesigned for this use. In surgical applications, the sensors have to be electrically passive and EMI compatible. Many kinds of sensors have been introduced for this application, namely, peizoresistive, strain gauges, etc. Although these sensors have many advantages in this regard, they are neither compatible with EMI environments nor electrically passive. So, a novel method of optical sensing need to be developed for these applications. The optical sensors may be fabricated in micro scales to overcome aforementioned needs. Some examples of optical force sensors work based on light transmission in optical fibers [1]. The proposed optical sensor is quite simple and it measures both force and displacement using only one moving object. In the proposed system, light from an optical fiber is reflected by an integrated mirror fabricated through micromachining. The light that gets coupled back into the fiber is dependent on the gap and angular misalignment between the fiber and mirror that varies with applied force and displacement. Finite element modeling of the sensor was carried out with COMSOL and optical loss was estimated for different applied forces. This paper presents the design, modeling and performance behavior of the proposed system in terms of optical loss for different applied loads.
A force sensor device has at least three arcs distributed around
" a central axis. The arcs have integrated sensing elements that
measure strain applied on the arc resulting from a force
applied on the central axis.
This paper presents a grasper-integrated force sensor that provides the capability of measuring dual axial forces at the tip of surgical robot for minimally invasive surgery (MIS). On the sensorized forceps, the combination of dual axial forces measured at each side of grasper presents three axial pulling and single axial grasping force sensing, which provide force feedback control using haptic device. It consists of simple structure of triangular prism shape and two capacitive-type pressure sensor cells based on elastomeric polymer which provides the information on normal and shear forces. The sensing principle is to compare the difference between responses of two pressure sensors when the surface of the sensor contacts to the tissue. A sensorized forceps is fabricated by employing the molding method and electronics for signal processing is embedded. Finally, experimental evaluations are performed and its feasibility is validated.
Visual color information is thought to affect human perception. This study proposes a master-slave system that performs force feedback compensation control based on the color of the target object. In this system, the ratio between forces exerted during tasks performed on dark and bright objects is used as a compensatory gain in the feedback force. The system is designed to maintain task consistency by ensuring a constant magnitude of force exerted during a task, even when the color of the target object varies. Basic experiments demonstrated that operators exert different forces on objects of the same weight but different color; in particular, the brightness of an achromatic object affects human perception of the force applied to it. In verification experiments, the difference between the force exerted on same-weight bright and dark colored objects by a master-slave system with no color-based compensation control was 2.24 N. Implementing the proposed control system, this difference was improved to 0.61 N. Therefore, this system can potentially ensure consistent work during tasks involving target objects of different colors.
The lack of haptic feedback has negatively affected the surgeon's ability to palpate and diagnose tissue and differentiate its stiffness during surgical operations with commercially available robotic assisted surgical systems. A modular surgical instrument capable of non-invasive measurement of sideways tip/tissue interaction forces for direct application in robotic assisted minimally invasive surgery systems is presented in this paper. The proposed force measurement technique enables the actual non-invasive measurement of the sideways interaction forces at the tip jaws. The instrument has two actuation degrees of freedom (DOF) for the tip operation and grasping orientation. The tip functionality type (e.g., grasping, cutting, and dissecting) can also be changed quickly and easily. Experiments were conducted to evaluate functionalities of the proposed instrument in palpating tissues. The results are presented and analysed here that verify the capability of the proposed instrument in accurately measuring lateral tip/tissue interaction forces.
An automated laparoscopic instrument capable of non-invasive measurement of tip/tissue interaction forces for direct application in robotic assisted minimally invasive surgery systems is introduced in this chapter. It has the capability to measure normal grasping forces as well as lateral interaction forces without any sensor mounted on the tip jaws. Further to non-invasive actuation of the tip, the proposed instrument is also able to change the grasping direction during surgical operation. Modular design of the instrument allows conversion between surgical modalities (e.g., grasping, cutting, and dissecting). The main focus of this paper is on evaluation of the grasping force capability of the proposed instrument. The mathematical formulation of fenestrated insert is presented and its non-linear behaviour is studied. In order to measure the stiffness of soft tissues, a device was developed that is also described in this chapter. Tissue characterisation experiments were conducted and results are presented and analysed here. The experimental results verify the capability of the proposed instrument in accurately measuring grasping forces and in characterising artificial tissue samples of varying stiffness.
Although recently Minimal Invasive Robotic Surgery (MIRS) has been more addressed because of its wide range of benefits, however there are still some limitations in this regard. In order to address the shortcomings of MIRS systems, various types of tactile sensors with different sensing principles have been presented in the last few years. In the present paper a MEMS-based optical sensor, which has been recently proposed by researchers, is investigated using numerical simulation. By this type of sensors real time quantification of both dynamic and statics contact forces between the tissue and surgical instrument would be possible. The presented sensor has one moving part and works based on the intensity modulation principle of optical fibers. It is electrically-passive, MRI-compatible and it is possible to be fabricated using available standard micro fabrication techniques. The behavior of the sensor has been simulated using COMSOL MULTIPHYSICS 3.5 software. Stress analysis is conducted on the sensor to assess the deflection of the moving part of the sensor due to applied force. The optical simulation is then conducted to estimate the power loss due to the moving part deflection. Using FEM modeling, the relation between force and deflection is derived which is necessary for the calibration of the sensor.
Human hand is an efficient manipulator in many aspects for multi-manipulation capability. This ability of hand is prevented from being employed in minimally invasive surgery (MIS) as in open surgery because human hand can't get into patient abdomen through small incision. We have developed a 10-DOF robotic metamorphic instrumental hand (MIH) prototype as a physical carrier of multi-manipulation. It is expected to enhance manipulation in robot-assisted MIS. Inspired from metamorphic mechanism theory, structure of the instrumental hand is designed to be variable. It can pass patient's abdomen skin in a straight cylinder shape through an incision of 24 mm in diameter. A three-fingered hand shape surgical device is rebuilt from this straight cylinder inside abdomen. The metamorphic instrumental hand is controlled with an isomorphic master glove. Master-slave mapping method is analyzed in system setup. Mapping errors are measured and compensated for the instrumental hand control. Eight preliminary manipulation experiments have been carried out on phantom tissue to validate multi-manipulation concept of this metamorphic instrumental hand.
The introduction of robot-assisted surgery in the operating room has led to significant improvements in surgeries. However, the lack of haptics feedback in these robotic systems using long teleoperated instruments has negatively affected the surgeon's ability to palpate tissue and diagnose it is healthy or unhealthy. This paper describes the design of a modular, automated laparoscopic grasper with 3D force feedback capability along with Robotic arm. The normal grasping forces, as well as, side ways manipulation forces during grasping and palpation tasks can be measured. Additionally, a modular design allows for easy conversion between surgical modalities. Calibration of the force sensors and initial testing of the prototype has shown its ability to accurately measure tool-tissue interaction forces. A complete Robotic system with tactile feedback consisting of a strain gauge force sensor mounted on Robotic end effector & servo motor based wireless control system has been proposed. A control jig at the master side in a bilateral master slave control setup to simplify the MMI has been proposed and a rotary potentiometer at the master side as a position sensor has been used. The prototype consists of 5 axes Robotics system, 3 for Laprascopic grasper and 2 for Robotic Arm has been designed.
Background:
Robotic-assisted minimally invasive surgery systems not only have the advantages of traditional laparoscopic instruments but also have other important advantages, including restoring the surgeon's hand-eye coordination and improving the surgeon's precision by filtering hand tremors. Unfortunately, these benefits have come at the expense of the surgeon's ability to feel. Various solutions for restoring this feature have been proposed.
Methods:
An actuated modular force feedback-enabled laparoscopic instrument was proposed that is able to measure tip-tissue lateral interaction forces as well as normal grasping forces. The instrument has also the capability to adjust the grasping direction inside the patient body. In order to measure the interaction forces, strain gauges were employed. A series of finite element analyses were performed to gain an understanding of the actual magnitude of surface strains where gauges are applied. The strain gauge bridge configurations were calibrated. A series of experiments was conducted and the results were analysed.
Results:
The modularity feature of the proposed instrument makes it interchangeable between various tip types of different functionalities (e.g. cutter, grasper, dissector). Calibration results of the strain gauges incorporated into the tube and at the base of the instrument presented the monotonic responses for these strain gauge configurations. Experimental results from tissue probing and tissue characterization experiments verified the capability of the proposed instrument in measuring lateral probing forces and characterizing artificial tissue samples of varying stiffness.
Conclusion:
The proposed instrument can improve the quality of palpation and characterization of soft tissues of varying stiffness by restoring sense of touch in robotic assisted minimally invasive surgery operations.
This paper reports on unique and scalable sensorized medical scissor blades for application in minimally invasive robotic surgery. The blades exploit the strain sensing capabilities of a single fiber Bragg grating (FBG) sensor bonded to the blade surface. This smart sensing structure allows detection of friction and material fracture forces during cutting and subsequently enables accurate estimation of the blade kinetic friction coefficient and fracture toughness values of the material being cut. We present theory on the determination of strain variation along the blade length during combined direct and lateral loading of the blade element during operation. Demonstration of the sensorized instrument is realized on an application specific experimental test-bed employing a commercial interrogation system for signal demodulation. Friction and cutting forces measured using the FBG are validated against load cell force data from the test-bed. Characterization tests showed that the sensorized blade has an unfiltered force sensing resolution of 0.5 N over a 30 N load range. This work demonstrates that a single optical fiber placed onto cutting instrument blades can, in an unobtrusive manner, reliably measure friction forces and material fracture properties during surgical cutting.
In der konventionellen robotergestützten, minimal invasiven Chirurgie (MIC) besteht eine vollständige mechanische Entkopplung zwischen Chirurg und Patient. Die Entwicklung kinästhetischer Rückkopplungssysteme ist fortgeschritten, die Rückkopplung taktiler Eindrücke ist jedoch nach wie vor problematisch. Es wurden viele Versuche unternommen, vollständige teletaktile Eindrücke zu vermitteln, die jedoch aus unterschiedlichen Gründen scheiterten. Als hauptsächlicher Grund hierfür ist anzusehen, dass die Ausgabeschnittstelle üblicherweise ein eigenständiges Gerät ist, was die gleichzeitige Wahrnehmung von Eindrücken und Steuerung des Instruments erschwert. Die menschliche Wahrnehmung taktiler Eindrücke beruht weitgehend auf dem Betasten des Objekts mit Bewegen des "Sensors", was mit zwei verschiedenen Geräten schwer nachzubilden ist. Außerdem war die Interpretation des rückgekoppelten Signals nicht eindeutig und intuitiv genug.
Eine der größten Schwierigkeiten in der (robotergestützten) minimal invasiven Chirurgie ist die große, durch die fehlende taktile Rückkopplung begründete Gefahr einer unbeabsichtigten Arterienverletzung mit der Folge schwer kontrollierbarer Blutungen. In der offenen Chirurgie kann Gewebe betastet werden, und ein Pulsieren deutet auf eine im Gewebe liegende Arterie hin. Eine Substitution des Tastsinns wäre aber auch aus anderen Gründen wünschenswert. So können in der offenen Herzchirurgie die präoperativ geplanten Anastomosestellen durch Betasten aufgefunden werden. Stehen jedoch nur optische Untersuchungsmethoden zur Verfügung, kann ein sehr zeitaufwendiges Freipräparieren der Arterien notwendig werden, um die präoperativ geplanten Anastomosestellen aufzufinden.
Die in dieser Arbeit vorgeschlagene Lösung bietet keine umfassende taktile Rückkopplung, sondern konzentriert sich auf das ultraschallgestützte, quasi taktile Lokalisieren besonderer Strukturen unter verdeckendem Gewebe. Mit den erfassten Daten erfolgt eine Modalitätssubstitution, dem Nutzer werden intuitive haptische bzw. Mehrkanalinformationen zurückgegeben. Um die Doppler-Frequenzverschiebung des in den betreffenden Arterien fließenden Blutes zu erkennen, wird ein Ultraschalltransducer verwendet, der in ein minimal invasives Instrument integriert ist. Die gemessenen Signale werden analysiert und an ein haptisches Eingabegerät weitergeleitet, mit dem die Erkennung und die Eigenschaften der verdeckten Gefäße intuitiv erfassbar dargestellt werden. Erste Versuche zeigten, dass ein leichtes Zucken des Eingabegerätes in Verbindung mit dem typischen Doppler-Geräusch das direkte Betasten sehr zuverlässig und intuitiv ersetzen. Weiterführende Untersuchungen, die die Verlässlichkeit bestätigen und zu einem tieferen Verständnis dieser Ergebnisse führen sollen, stehen noch aus.
Es ist sehr fraglich, ob eine vollständige Rückkopplung aller möglichen taktilen Eindrücke in der robotergestützten MIC erstrebenswert ist – der medizinische Nutzen scheint die Anstrengungen und Kosten nicht zu rechtfertigen. Deshalb verspricht, wie in dieser Arbeit, der Ersatz nur von Teilen der Taktilität, der mit der menschlichen Wahrnehmung vergleichbar ist, eine bessere Lösung zu sein. Im Gegensatz zu in der Literatur beschriebenen Realisierungen, die sich im praktischen Einsatz nicht durchgesetzt haben, hat das hier beschriebene System erste Tests bestanden und seine überlegene Leistungsfähigkeit bewiesen. Ein Patent hierzu wurde bereits erteilt.
In traditional open surgery, surgeons use their fingertip palpation to investigate the hidden anatomical structures of tissue. However, in the current commercially available minimally invasive robotic surgery (MIRS) systems, while surgical instruments interact with tissues, surgeons do not sense any tactile information. Therefore, tactile sensors are required to be integrated into the tips of surgical instruments to mimic the perception of the surgeon's fingertips. The electrically based tactile sensors that exist at present cannot usually operate under static loading conditions. In addition, they are not compatible with magnetic resonance imaging (MRI) devices. Therefore, this research was aimed at restoring tactile information by developing an MRI compatible optical fiber tactile sensor. The sensor consists of only one single moving part. Thanks to this novel design, the sensor does not require the use of an array of sensors to measure the distributed tactile information. This capability simplifies the integration of the sensor into any suitable space available at the tips of surgical instruments. In addition, the sensor performs under both static and dynamic loading conditions. A theoretical model of the sensor and a finite-element model of the sensor-tissue interaction were developed. To validate the sensor, a prototype of the sensor was fabricated and tested.
This paper describes a three-fingered nine-degrees-of-freedom hand whose parts can be inserted through trocars and assembled inside the abdominal cavity. Unlike other studies of surgery robots, this study focuses on a nondominant hand of a surgeon and its goal is to develop a robotic hand that can carry out assistive tasks for surgery, as if the human nondominant hand existed in the abdominal cavity. Another advantage of such a robotic hand is that it can grasp and retract large internal organs. The assemblage of the developed hand consists of center, right, and left finger units. The center finger unit is inserted through one trocar, and the right and left finger units are inserted through another trocar and then passed through the trocar, where the center finger unit is inserted. Then, the three finger units are connected to form the hand. One notable advantage of this assembly procedure is that the power transmission used to drive the finger joints is connected outside the abdominal cavity, which makes assembly and disassembly much easier and safer than the previously proposed hand. Although the hand has no wrist, its three finger joints play the role of a wrist joint. In vivo experiments demonstrate that the assembly procedure is simple, and that the hand can be made to grasp, hold up, and retract large internal organs, such as small intestine and spleen, by manipulating its joints in such a way that the hand fits the shape of the organ.
This paper presents a force visualization mechanism for endoscopic surgical instruments using a Moirée fringe. This mechanism can display fringes or characters that correspond to the magnitude of a force between the surgical instruments and internal organs without the use of electronic elements, such as amplifiers and strain gauges. As this mechanism is simply attached to the surgical instruments, there is no need for additional devices in the operating room or wires to connect these devices. The structure is simple, and its fabrication is inexpensive. An example is shown with the mechanism mounted on a 10-mm forceps. We experimentally verified in vivo, using a pig, that it can display characters corresponding to the magnitude of the force, thus visually displaying the force even in endoscopic image.
In laparoscopic surgery, surgeons perform surgery in the abdominal cavity by using only slender instruments that can be inserted through small diameter trocars. When it is difficult to perform surgery by using only instruments for laparoscopic surgery, they often make a 7-8 cm incision through which their hand can be inserted. Clearly this is invasive compared with complete laparoscopic surgery. This paper proposes an assemblable mechanical hand like a human hand that can be inserted through trocars. We already developed a three-fingered three-degree of freedom assemblable hand. The purpose of this paper is to develop an assemblable hand with more degrees of freedom that can grasp/push aside large internal organs and open membranes. The developed hand has three fingers with a total of five degrees of freedom. Its power transmission mechanisms and assembling method are completely different from those of the previous hand. The hand is assembled from body and finger units with an installation tool. The finger unit is fixed to the body unit with only one screw by using the installation tool. To drive the fingers, power is transmitted with cables, gears and shafts. Experimental results verify that the hand can be assembled in a closed space and that it can grasp and push aside various objects.
Force feedback systems have been developed to improve the user-friendliness of robotic surgery systems. In teleoperative surgery, one of the major problems is the delay of the transmission of the information from the operation site to the surgery site. The transmission delays of the control signal and force information are less than the that of the image signal. In many cases, the visual information is synchronized with the force information in order to avoid a time gap between them. In this paper, we propose that force information be presented earlier than the visual information. This approach reduces the damage to the organs in surgical operations even though there is a time gap between the delay of force information and visual information. In addition, we propose a method to present predicted force information to avoid damage to the organs due to time delays in teleoperative surgery. The liver can be treated with a contact force of less than 0.8 N and a grasping force of less than 1.1 N by applying the proposed method. The method can realize a teleoperative surgery without damaging the patient's organs.
Minimally invasive surgery (MIS) challenges the surgeon's skills due to his/her separation from the operation area, which can be reached with long instruments only. Therefore, the surgeon looses access to the manipulation forces inside the patient. This reduces his/her dexterity when performing the operation. A new compact and lightweight robot for MIS is presented, which allows for the measurement of manipulation forces. The main advantage of this concept is that no miniaturized force sensor has to be integrated into surgical instruments and inserted into the patient. Rather, outside the patient, a standard sensor is attached to a modified trocar, which allows for the undisturbed measurement of manipulation forces. This approach reduces costs and sterilizability demands. Results of in vitro and in vivo force control experiments are presented to validate the concepts
Advancements in robotics have led to significant improvements in robot-assisted minimally invasive surgery. This paper describes our design of an automated laparoscopic grasper with tri-directional force measurement capability at the grasping jaws. The laparoscopic tool can measure normal, lateral, and longitudinal grasping forces while grasping soft tissue. Additionally, the tool can also be used to measure the tissue probing forces. Initial testing of the prototype has shown its ability to accurately characterize artificial tissue samples of varying stiffness and accurately measure the probing forces.
Gaining access to a surgical site via retracting neighboring tissue can result in complications due to occlusion of the tissue blood supply resulting in ischemic damage. By incorporating oxygenation sensors on the working surfaces of surgical retractors and graspers, it is possible to measure the local tissue oxygen saturation and look for trends in real-time. Further, by measuring tissue interaction forces simultaneously, we can further augment the information available to the surgeon. The sensors provide a means for sensory substitution to help compensate for the decreased sensation present in minimally invasive laparoscopic and robotic procedures that are gaining significant popularity. Sensing surgical instruments will allow for safer and more effective surgeries while not interfering with the normal workflow of a procedure
Minimally Invasive Surgery (MIS) has enjoyed increasing attention and development over the last two decades. As MIS systems evolve, the surgeon is increasingly insulated from patient contact, creating a trade-off between surgi- cal sensory information and patient invasiveness. Incorporation of haptic feed- back into MIS systems promises to restore sensory information surrendered in favor of minimal invasiveness. We have developed a novel, biocompatible 2- DOF force-sensing sleeve that can be used modularly with a variety of 5mm laparoscopic instruments. The functional requirements for such a device are de- fined, and design strategies are explored. Our formal device design is outlined and device calibration is presented with derived calibration functions. Illustrative experimental force data from a porcine model is presented. This device can be used for intra-abdominal force recording and feedback in laparoscopic environ- ments; the implications and future potential for this technology are explored.
Minimally invasive surgery involves a multidimensional series of tasks requiring a synthesis between visual information and the kinematics and dynamics of the surgical tools. Analysis of these sources of information is a key step in mastering MIS, but may also be used to define objective criteria for characterizing surgical performance. The BlueDRAGON is a new system for acquiring the kinematics and dynamics of two endoscopic tools synchronized with the visual view of the surgical scene. It includes two four-bar passive mechanisms equipped with position and force torque sensors for measuring the positions and orientations of the two endoscopic tools along with the forces and torques (F/T) applied by the surgeon's hands. The methodology of decomposing the surgical task is based on a fully connected, 28 finite-states Markov model where each states corresponded to a fundamental tool/tissue interaction based on the tool kinematics and associated with unique F/T signatures. The experimental protocol includes seven MIS tasks performed on an animal model by 30 surgeons at different levels of their residency training including expert surgeons. From the preliminary analysis of these data, the major differences between residents at different skill levels are discussed. Systems like surgical robots or virtual reality simulators that inherently measure the kinematics and dynamics of the surgical tool may benefit from inclusion of the proposed methodology for the analysis of efficacy and objective evaluation of surgical skills during training.
We report a computerized endoscopic surgical grasper with computer control and a force feedback (haptic) user interface. The system uses standard unmodified grasper shafts and tips. The device can control grasping forces either by direct surgeon control, via teleoperation, or under software control. In this paper, we test an automated palpation function in which the grasper measures mechanical properties of the grasped tissue by applying a programmed series of squeezes. Experimental results show the ability to discriminate between the normal tissues of small bowel, lung, spleen, liver, colon, and stomach. We anticipate applications in telesurgery, clinical endoscopic surgery, surgical training, and research.
Nowadays, the surgeon who is using minimally invasive tools loses
almost completely the haptic perception of the manipulated tissue. In
particular, he or she loses the perception of the tissue elastic
properties. It is possible to modify the actual mini-invasive surgical
tools in such a way that they may give a reliable estimation of the
manipulated tissue properties for recognition and characterization
purpose. In this paper we present a first attempt to realize a prototype
of sensor-based surgical tool using a modified commercial tool.
Experimental tests have shown that using such a tool could enhance
surgeon's haptic perception of the manipulated tissue
This paper presents an overview of the design and development of electromechanical haptic devices that can be used as a part of the training environment of laparoscopic surgeons (minimally invasive surgery, MIS). The paper first presents results of the experimental study of measuring the expected forces that the user hand can experience when using long stem surgical tools that are used in laparoscopic surgery. In general and in performing laparoscopic procedures, the user can feel reaction forces arising from the interaction of the surgical tools with the organs along four dominant directions and also to some extent between the palm and the fingers of the hand. Design challenges are to develop a high-bandwidth system which allows the creation of such a force feedback along the desired degrees of freedom. This paper presents the design and development experiences that a group of us at Simon Fraser University has gained during the past 7 years. We present evolutionary designs from the one degree of freedom haptic feedback design to more complex four degrees of freedom. Some comparisons have also been made between the proposed design and commercially available ones.
GENERAL: A force sensor has been designed and fabricated that will fit to existing laparoscopic grasping forceps (Babcocks) from Ethicon Endosurgery Inc. The goal of the sensor development is to provide tool-tissue force information to the surgeons so that surgeons can regain the sense of touch that has been lost through laparoscopy. Eventually, force sensing will provide feedback for robotic laparoscopic surgical platforms.
We have developed a prototype force sensor system with ATI Industrial Automation. This tool is provided as an in-line transducer with six degrees of freedom that can retrofit current Babcocks. The sensor is currently being used in clinical trials with animals to determine the benefits. The sensor system utilizes industry proven technology in combination with a custom transducer and user interface. A GUI is part of the system and provides resolved force magnitude data in a graphical format for case of interpretation. Sterilization, size, and ease of use are addressed by the current design. Operating room reliability and safety are currently being investigated.
A three phase experimental trial using a porcine model is being completed that will test the hypothesis that force information can be used to minimize tissue trauma during laparoscopic surgery.
Based on our research, there is strong evidence that surgeons would benefit from information regarding the levels of force applied to tissues. In the future, robotic surgery will require force sensing. Surgical simulators could provide force feedback during simulated surgical procedures by using a sensor platform such as this. In addition, tool tip design in the future will benefit from the application of this technology and data base.
To evaluate the role of force feedback with applications to minimally invasive surgery (MIS). Two research hypotheses were tested using our automated laparoscopic grasper.
Conventional laparoscopic tools do not have the ability of providing force feedback to a surgeon when in use with or without robotic surgical systems. Loss of haptic (force and tactile) feedback in MIS procedures is a disadvantage to surgeons since they are conventionally used to palpating tissues to diagnose tissues as normal or abnormal. Therefore, the need exists to incorporate force feedback into laparoscopic tools.
We have developed an automated laparoscopic grasper with force feedback capability to help surgeons differentiate tissue stiffness through a haptic interface device. We tested our system with 20 human subjects (10 surgeons and 10 nonsurgeons) using our grasper to evaluate the role of force feedback to characterize tissues and answer 2 research hypotheses.
Our experiments confirmed 1 of our 2 research hypotheses, namely, providing both vision and force feedback leads to better tissue characterization than only vision feedback or only force feedback.
We have validated 1 of our 2 research hypotheses regarding incorporating force feedback with vision feedback to characterize tissues of varying stiffness.
A novel haptic interface was designed and developed for use in manipulation tasks. The force feedback mechanism consists of three degrees of spatial force feedback (x, y, and z directions) and 1 degree of grasping/parting (increasing the distance between two or more points) force feedback. This device also provides a net of three additional passive joints for a total of 7 degrees-of-freedom.
Minimally invasive surgery involves inserting special instruments into the body cavity through tiny incisions in order to perform surgical procedures. In this paper, the design of a robotic master-slave system for use in minimally invasive surgery is discussed. This system is capable of providing haptic feedback to the surgeon in all available degrees of freedom. System design as well as master and slave bilateral control and communication issues are discussed.
Present-day commercial endoscopic graspers do not have any
built-in sensors, thus, the surgeon does not have the necessary tactile
feedback to manipulate the tissue safely. This paper presents the
design, fabrication, testing, and experimental results of a
micromachined tactile sensor, which can be integrated with the tips of
commercial endoscopic graspers. The prototype sensor consists of three
layers. The top layer is made of micromachined silicon with a rigid
tooth-like structure similar to the present-day endoscopic grasper. The
bottom layer is made of flat Plexiglass serving as a substrate. Packaged
between the Plexiglass and the silicon is a patterned Polyvinglidene
Fluoride (PVDF) film. The proposed sensor exhibits high sensitivity, a
large dynamic range, and a high signal-to-noise ratio. Through
experimental results, it is shown that the magnitude and position of an
applied force can be determined from the magnitude and slope of the
output signals from the PVDF sensing elements. Structural analysis is
also performed using the finite-element method, and the results are
compared with the experimental analysis. The advantages and limitations
of this sensor are also reported. A discussion of how the design of the
sensor can be integrated with the design of an endoscopic grasper is
also presented
Force Sensor for Laparoscopic Babcock," presented at Medicine Meets Virtual Reality
- R Curet
- T I Bocklage
- L Macfarlane
- Kory
Curet, R. Bocklage, T. I. MacFarlane, and L. Kory, "Force Sensor for Laparoscopic Babcock," presented at Medicine Meets Virtual Reality, 354-361, 1997.