Advances in Bio-Tactile Sensors for Minimally Invasive Surgery Using the Fibre Bragg Grating Force Sensor Technique:A Survey
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paper_title: A micro optical force sensor for force feedback during minimally invasive robotic surgery

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Abstract A 5 mm diameter tri-axial force sensor has been developed for minimally invasive robotic surgery. To define the required force range and resolution, a needle driver has been equipped with strain gauges. In vivo tests with different types of needles and tissue show that the required force range and resolution are, respectively, 2.5 N and 0.01 N. The new sensor is based on a flexible titanium structure of which the deformations are measured through reflective measurements with three optical fibres. It has a range of 2.5 N in axial direction and 1.7 N in radial direction.
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paper_title: State-of-the-Art in Force and Tactile Sensing for Minimally Invasive Surgery

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Haptic perception plays a very important role in surgery. It enables the surgeon to feel organic tissue hardness, measure tissue properties, evaluate anatomical structures, and allows him/her to commit appropriate force control actions for safe tissue manipulation. However, in minimally invasive surgery, the surgeon's ability of perceiving valuable haptic information through surgical instruments is severely impaired. Performing the surgery without such sensory information could lead to increase of tissue trauma and vital organic tissue damage. In order to restore the surgeon's perceptual capability, methods of force and tactile sensing have been applied with attempts to develop instruments that can be used to detect tissue contact forces and generate haptic feedback to the surgeon. This paper reviews the state-of-the-art in force and tactile sensing technologies applied in minimally invasive surgery. Several sensing strategies including displacement-based, current-based, pressure-based, resistive-based, capacitive-based, piezoelectric-based, vibration-based, and optical-based sensing are discussed.
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paper_title: Novel Contact Force Sensor Incorporated in Irrigated Radiofrequency Ablation Catheter Predicts Lesion Size and Incidence of Steam Pop and Thrombus

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Background— An open-irrigated radiofrequency (RF) ablation catheter was developed to measure contact force (CF). Three optical fibers measure microdeformation of the catheter tip. The purpose of this study was to (1) validate the accuracy of CF sensor (CFS) (bench test); and (2) determine the relationship between CF and tissue temperatures, lesion size, steam pop, and thrombus during RF ablation using a canine thigh muscle preparation. ::: ::: Methods and Results— CFS measurements (total 1409) from 2 catheters in 3 angles (perpendicular, parallel, and 45°) were compared with a certified balance (range, 0 to 50 g). CFS measurements correlated highly ( R 2≥0.988; mean error, ≤1.0 g). In 10 anesthetized dogs, a skin cradle over the thigh muscle was superfused with heparinized blood at 37°C. A 7F catheter with 3.5-mm saline-irrigated electrode and CFS (Endosense) was held perpendicular to the muscle at CF of 2, 10, 20, 30, and 40 g. RF was delivered (n=100) for 60 seconds at 30 or 50 W (irrigation 17 or 30 mL/min). Tissue temperature (3 and 7 mm depths), lesion size, thrombus, and steam pop increased significantly with increasing CF at each RF power. Lesion size was greater with applications of lower power (30 W) and greater CF (30 to 40 g) than at high power (50 W) with lower CF (2 to 10 g). ::: ::: Conclusions— This novel ablation catheter, which accurately measures CF, confirmed CF is a major determinant of RF lesion size. Steam pop and thrombus incidence also increases with CF. CFS in an open-irrigated ablation catheter that may optimize the selection of RF power and application time to maximize lesion formation and reduce the risk of steam pop and thrombus. ::: ::: Received July 10, 2008; accepted October 6, 2008. ::: ::: # CLINICAL PERSPECTIVE {#article-title-2}
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paper_title: Planar and finger-shaped optical tactile sensors for robotic applications

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Progress is described regarding the development of optical tactile sensors specifically designed for application to dexterous robotics. These sensors operate on optical principles involving the frustration of total internal reflection at a waveguide/elastomer interface and produce a grey-scale tactile image that represents the normal (vertical) forces of contact. The first tactile sensor discussed is a compact, 32*32 planar sensor array intended for mounting on a parallel-jaw gripper. Optical fibers were employed to convey the tactile image to a CCD camera and microprocessor-based image analysis system. The second sensor had the shape and size of a human fingertip and was designed for a dexterous robotic hand. It contained 257 sensing sites (taxels) distributed in a dual-density pattern that included a tactile fovea near the tip measuring 13*13 mm and containing 169 taxels. The design and construction details of these tactile sensors are presented, in addition to photographs of tactile imprints. >
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paper_title: Recording compliance of dental splint use in obstructive sleep apnoea patients by force and temperature modelling

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Fibre-optic sensors are used to monitor the force and temperature of dental splints worn by patients suffering from sleep apnoea. Owing to the small size of the sensors, they can be easily embedded within the splint in a way that does not affect the effectiveness of the splint, and, at the same time, are able to indicate whether the splint has been properly worn by the patient. The overall dimensions of the sensor are approximately 0.375 mm thickness, 1 cm length and 3 mm width. The force and temperature sensors are calibrated and found to have sensitivities of better than 0.5N and 0.1°C, respectively. Trials performed on patients show that the measurement of pressure and temperature is an effective way of monitoring the proper usage of the dental splint by the patients.
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paper_title: Kinematics and workspace modeling of a new hybrid robot used in minimally invasive surgery

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The geometric and kinematic models of a new surgical hybrid robot used for camera and active instruments positioning are presented in this paper. The robot workspace is computed and illustrated following the singularities analysis. The robot structure consists of two modules: the PARAMIS robot, and the new serial positioning module. The serial positioning module is used to obtain a mechanically fixed remote center of motion (RCM), enabling the structure to manipulate also active instruments. The new robot provides the necessary motion control to respect the particularities and restrictions of surgical applications. The detailed workspace analysis demonstrates the importance of the relative positioning between the robot and the patient. A constructive solution of the new serial module, the numerical results and conclusions from the performed simulations are described.
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paper_title: Discretely Loaded Beam-Type Optical Fiber Tactile Sensor for Tissue Manipulation and Palpation in Minimally Invasive Robotic Surgery

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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.
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paper_title: Development of a dexterous minimally-invasive surgical system with augmented force feedback capability

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Several robotic surgical systems have been developed for minimally-invasive surgery including commercialized products such as da Vinci and ZEUS. We have developed a minimally-invasive surgical system, which had performed remote surgery experiments for four times until now (performed on pigs over 150 km in Japan). In this paper, two approaches that extend the system from the perspective of extensions of surgeon's dexterity are described. The first approach is a development of complex robotic forceps, which have multiple d.o.f. on their tip. A complex rigid link mechanism has been applied to the robotic forceps to realize 3 d.o.f. motions in a patient's abdominal cavity. With the rigid link mechanism, surgeons have no longer need to be concerned a cable cutting problem, which often can be happened on conventional cable driven systems. The second approach is a force feedback capability. The developed rigid link mechanism is preferable for an implementation of a force feedback capability. The force feedback capability is important not only for extending surgeon's dexterity but also for preventing unexpected damage on internal organs. An evaluation experiment of the force feedback capability on a simulated surgical procedure was conducted. An augmented force presentation method was developed that displays contact information between forceps and soft tissues. In an evaluation experiment, the load applied to soft organ tissues was reduced by approximately 30% compared with a conventional force feedback method.
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paper_title: A Miniature Microsurgical Instrument Tip Force Sensor for Enhanced Force Feedback During Robot-Assisted Manipulation

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This paper reports the development of a new miniature force sensor designed to measure contact forces at the tip of a microsurgical instrument in three dimensions, and its application to scaled force feedback using a cooperatively manipulated microsurgical assistant robot. The principal features of the sensor are its small size of 12.5 mm in diameter and 15 mm in height, a novel configuration of flexure beams and strain gauges in order to measure forces isotropically at the instrument tip 40 mm from the sensor body, and sub-mN three-axis force-sensing resolution.
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paper_title: A micromachined piezoelectric tactile sensor for an endoscopic grasper-theory, fabrication and experiments

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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.
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paper_title: Decreasing strain on the surgeon in gynecologic minimally invasive surgery by using semi-active robotics

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Abstract Objective To assess the advantages of a surgeon-controlled robotic endoscope holder in gynecologic minimally invasive solo-surgery as compared with conventional assistance with a second surgeon. Methods One hundred gynecologic laparoscopies were consecutively allocated to surgery with either a robot as the surgical assistant or a conventional assistant surgeon. Total operation time, image stability, and frequency of corrective maneuvers of the camera, in addition to the surgeon's satisfaction regarding the ergonomics of the intervention, were recorded. All interventions were performed by the same surgeon. All laparoscopic surgery was classified as either easy or advanced surgery. Results The image stability score was significantly higher (10 vs 7; P Conclusion The robot does not prolong total operation time and increases the surgeon's comfort by improving image stability and laparoscope handling. It could provide major benefit, especially in complex gynecologic laparoscopic surgery.
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paper_title: Force sensing microinstrument for measuring tissue properties and pulse in microsurgery

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Miniaturized and "smart" instruments capable of characterizing the mechanical properties of tiny biological tissues are needed for research in biology, physiology, and biomechanics, and can find very important clinical applications for diagnostics and minimally invasive surgery (MIS). We are developing a set of robotic microinstruments designed to augment the performance of surgeons and clinicians during MIS. These microtools are intended to restore (or even enhance) the finger palpation capabilities that the surgeon exploits to characterize tissue hardness and to measure pulsating vessels in traditional surgery, but which are substantially reduced in MIS. This paper describes the main applications and the performance of a prototype miniature robotic instrument consisting of a microfabricated microgripper, instrumented with semiconductor strain-gauges as force sensors. The experimental set-up used for the in vitro tests reported in this paper consists of the microprobe mounted on a workstation and teleoperated. A haptic interface provides force feedback to the operator. We have demonstrated that the system can discriminate, both qualitatively and quantitatively, tiny skin samples based on their different elastic properties, and "feel" microvessels on the basis of pulsating fluid flowing through them.
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paper_title: Development of FBG sensor system for force-feedback in minimally invasive robotic surgery

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Force feedback plays a very important role in medical surgery. In minimally invasive surgery (MIS), however, the very long and stiff bars of surgical instruments greatly diminish force-feedback to the surgeon. In the case of minimally invasive robotic surgery (MIRS), force-feedback is totally eliminated. Previous researchers have reported that the absence of force-feedback increased the average force magnitude applied to the tissue by at least 50%, and increased the peakforce magnitude by at least a factor of two. Therefore, it is very important to provide force information in MIRS. Recently, many sensors are being developed for MIS and MIRS, but some obstacles to their application in actual medical surgery must be surmounted. The most critical problems are size limit and sterilizability. Optical fiber sensors are among the most suitable sensors for the surgical environment. The optical fiber Bragg grating (FBG) sensor in particular offers an important additional advantage over other optical fiber sensors in that it is not influenced by the intensity of the light source. In this paper, we present the initial results of a study on the application of a FBG sensor to measure reflected forces in MIRS environments and suggest the possibility of successful application to MIRS systems.
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paper_title: Robotic tactile sensor array fabricated from a piezoelectric polyvinylidene fluoride film

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A robotic tactile sensor comprised of 25 discrete sensor electrodes arranged in a 5*5 grid was designed and fabricated from a piezoelectric polyvinylidene fluoride (PVDF) film coupled to an integrated circuit (IC). Each of the 25 sensing electrodes in the IC grid were connected to metal-oxide-semiconductor field effect transistor (MOSFET) amplifiers which provided sufficient gain to generate usable response signal levels. Sensors fabricated from varying thicknesses of PVDF film are evaluated. The sensor based on the 25- mu m-thick PVDF film was considered to be the optimal sensor configuration, based on its bias-time performance and its linear response over the loading range tested (0/8 to 76.0 grams). There was no detectable coupling between the nearest-neighbor sensing elements in any of the sensor configurations. As a demonstration, the optimal sensor configuration is used to recognize a toroidal-shaped load. >
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paper_title: Fiber Optic Sensors

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Fiber optic sensors have become indispensable tools for biomedical study because of their unique features such as (1) high sensitivity, (2) small footprint and endoscopic compatibility, (3) multiple agent distributive sensing capability, and (4) immunity from electromagnetic interference. In this chapter, we will provide a brief overview on the basic principle of fiber optic sensors, types of fiber optic sensors, and their applications to biomedical sensing. As a result of the page limitation, important work in this area may not be included in this chapter. Readers may find those contents in the listed reference material. ::: ::: ::: Keywords: ::: ::: fiber optic sensors; ::: light; ::: sensing mechanism; ::: biomedical sensing
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paper_title: Optical Microsystems for Static and Dynamic Tactile Sensing: Design, Modeling, Fabrication and Testing

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Minimally invasive surgical operations encompass various surgical tasks ranging from conventional endoscopic/laparoscopic methods to recent sophisticated minimally invasive surgical techniques. In such sophisticated techniques, surgeons use equipment varying from robotic-assisted surgical platforms for abdominal surgery to computer-controlled catheters for catheter-based cardiovascular surgery. Presently, the countless advantages that minimally invasive surgery offers for both patients and surgeons have made the use of such surgical operations routine and reliable. However, in such operations, unlike conventional surgical operations, surgeons still suffer from the lack of tactile perception while interacting with the biological tissues using surgical instruments. To address this issue, it is necessary to develop a tactile sensor that can mimic the fingertip tactile perceptions of surgeons. In doing so and to satisfy the needs of surgeons, a number of considerations should be implemented in the design of the tactile sensors. ::: First, the sensor should be magnetic resonance compatible to perform measurements even in the presence of magnetic resonance imaging (MRI) devices. Currently, such devices are in wide-spread use in surgical operation rooms. Second, the sensor should be electrically-passive because introducing electrical current into the patients’ body is not desirable in various surgical operations such as cardiovascular operations. Third, the sensor should perform measurements under both static and dynamic loading conditions during the sensor-tissue interactions. Such a capability of the sensor ensures that surgeons receive tactile feedback even when there is continuous static contact between surgical tools and tissues. Essentially, surgeons need such feedback to make surgical tasks safer. In addition, the size of the sensor should be miniaturized to address the size restrictions. In fact, the combination of intensity-based optical fiber sensing principles and micro-systems technology is one of the limited choices that address all the required considerations to develop such tactile sensors in a variety of ways. ::: The present thesis deals with the design, modeling, manufacturing, testing, and characterizing of different tactile sensor configurations based on detection and integration methods. The various stages of design progress and principles are developed into different design configurations and presented in different chapters. The main sensing principle applied is based on the intensity modulation principle of optical fibers using micro-systems technology. In addition, a hybrid sensing principle is also studied by integrating both optical and non-optical detection methods. The micromachined sensors are categorized into five different generations. Each generation has advantages by comparison with its counterpart from the previous generation. The initial development of micromachined sensors is based on optical fiber coupling loss. In the second phase, a hybrid optical-piezoresistive sensing principle is studied. The success of these phases was instrumental in realizing a micromachined sensor that has the advantage of being fully optical. This sensor measures the magnitude of concentrated and distributed force, the position of a concentrated force, the variations in the force distribution along its length, the relative hardness of soft contact objects, and the local discontinuities in the hardness of the contact objects along the length of the contact area. Unlike most electrical-based commercially-available sensors, it performs all of these measurements under both static and dynamic loading conditions. Moreover, it is electrically passive and potentially MRI-compatible. The performances of the sensors were experimentally characterized for specific conditions presented in this thesis. However, these performances are easily tunable and adjustable depending upon the requirements of specific surgical tasks. Although the sensors were initially designed for surgical applications, they can have numerous other applications in the areas of robotics, automation, tele-display, and material testing.
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paper_title: Pixel-based optical fiber tactile force sensor for robot manipulation

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This paper investigates novel tactile sensing concepts of a fiber optic sensor that can be integrated with minimally invasive surgical (MIS) manipulation tools whilst being Magnetic Resonance (MR) compatible. A 3×3 tactile optical fiber sensor was developed, and is able to measure applied normal forces. Forces are converted from the deflections of a set of nine flexures that are connected to a system of mirrors which, in turn, reflect light received from transmitting fibers to detection fibers. The changes in light intensity are ultimately read-out by a camera system. The images received by the camera attached at the end of the detection fibers are then processed on a computer system using Matlab. Employing a calibration process, the applied forces can be related to the number of activated pixels per received fiber image. This system enables an array of tactile flexures to be recorded via a single camera.
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paper_title: In-Line Fiber Optic Interferometric Sensors in Single-Mode Fibers

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In-line fiber optic interferometers have attracted intensive attention for their potential sensing applications in refractive index, temperature, pressure and strain measurement, etc. Typical in-line fiber-optic interferometers are of two types: Fabry-Perot interferometers and core-cladding-mode interferometers. It's known that the in-line fiber optic interferometers based on single-mode fibers can exhibit compact structures, easy fabrication and low cost. In this paper, we review two kinds of typical in-line fiber optic interferometers formed in single-mode fibers fabricated with different post-processing techniques. Also, some recently reported specific technologies for fabricating such fiber optic interferometers are presented.
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paper_title: Miniaturized triaxial optical fiber force sensor for MRI-Guided minimally invasive surgery

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This paper describes the design and construction of a miniaturized triaxial force sensor which can be applied inside a magnetic resonance imaging (MRI) machine. The sensing principle of the sensor is based on an optical intensity modulation mechanism that utilizes bent-tip optical fibers to measure the deflection of a compliant platform when exposed to a force. By measuring the deflection of the platform using this optical approach, the magnitude and direction of three orthogonal force components (F x , F y , and F z ) can be determined. The sensor prototype described in this paper demonstrates that it can perform force measurements in axial and radial directions with working ranges of +/− 2 N. Since the sensor is small in size and entirely made of nonmetallic materials, it is compatible with minimally invasive surgery (MIS) and safe to be deployed within magnetic resonance (MR) environments.
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paper_title: Fiber grating sensors in medicine: Current and emerging applications

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Fiber grating sensors hold immense potential for biomedical applications due to their inherent properties like small size, biocompatibility, non-toxicity, chemical inertness and electromagnetically inert nature. Grating based sensors are well known technology for structural health monitoring (SHM) in the arena of civil and aerospace; however investigations for their use in the field of medicine are fairly recent and they have not been yet commercialized for the same. As these sensors detect strain, temperature, pressure, vibration, curvature and refractive index of the surrounding material even in high magnetic and electric field environments, they can serve diagnostic purposes in diverse areas of healthcare e.g. biomechanics, cardiology, gynecology, very low temperature monitoring and immunosensing to name a few. Most importantly, they can be used efficiently for thermal and pressure mapping even during MRI procedure where conventional sensors may fail. The paper is a review of various application areas of fiber grating based devices, the status of precedent and ongoing research around the world, and discussion on the issues hampering their rapid growth in the field.
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paper_title: Prototype of Instrument for Minimally Invasive Surgery with 6-Axis Force Sensing Capability

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Minimally invasive surgery (MIS) challenges the surgeon’s skills due to his separation from the operation area which can only be reached with long instruments. To overcome these drawbacks, minimally invasive robotic surgery (MIRS) plays an important role. This paper describes the development of actuated and sensorized instruments for minimally invasive robotic surgery which help to increase the surgeon’s immersion and dexterity.
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paper_title: Surgical Robotics and Laparoscopic Training Drills

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Purpose: We investigated the impact of robotics on surgical skills by comparing traditional laparoscopy with the da Vinci Surgical System in the performance of various laparoscopic training drills. Subjects and Methods: Twenty-one surgeons performed eight timed drills of increasing difficulty with a laparoscopic trainer and the da Vinci Surgical System (Intuitive Surgical Sunnyvale, CA). The mean time to drill completion, drill time variance, and statistical analysis were performed. Surgeons were also questioned about their perception of the robotic technology following completion of the drill series. Results: The mean time required to complete the first drill was 69 seconds with laparoscopy and 57 seconds with the robotic system. The mean times for drill two were 67 seconds with laparoscopy and 44 seconds with robotics; for drill three, the times were 88 seconds for laparoscopy and 61 seconds for robotics, and for drill four, 186 seconds with laparoscopy and 71 seconds with robotics. Only the first drill...
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paper_title: Ischemia and Force Sensing Surgical Instruments for Augmenting Available Surgeon Information

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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
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paper_title: Large-dynamic-range and high-resolution from a strain sensing system using long-period grating interrogating FBG strain sensor

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We have demonstrated both large-dynamic range (8100 /spl mu//spl epsiv/) and high-resolution (0.5 /spl mu//spl epsiv/) from a strain sensing system using a long-period grating interrogating a fibre Bragg grating sensor. The sensor demonstrates both large dynamic sensing range and high resolution.
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paper_title: Soft tactile sensor arrays for micromanipulation

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Micromanipulation methods used for complicated tasks such as microrobot assembly and microvascular surgery often lack the force reflection and contact localization capability necessary to achieve robust grasps of micro-scale objects without applying excessive forces. This absence of haptic feedback is especially prohibitive in cases where visual evidence of force application, such as object surface deformation, is imperceptible and where unstructured, dynamically changing environments require force sensing and modulation for safe, atraumatic object manipulation. This paper describes the design, fabrication, and experimental validation of a soft tactile sensor array for sub-millimeter contact localization and contact force measurement during micromanipulation. The geometry and placement of conductive liquid embedded channels within the sensor array are optimized to provide adequate sensitivity for representative micro-manipulation tasks. Mechanical testing of the sensor demonstrates a sensitivity of less than 50mN and contact localization resolution on the order of 100's of microns.
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paper_title: Tactile sensor arrays using fiber Bragg grating sensors

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This paper describes two kinds of 3 × 3 force sensor arrays using fiber Bragg gratings (FBG) and transducers for tactile sensation to detect a distributed normal force. One array is developed for a large area tactile sensor that has good sensitivity but low spatial resolution, similar to human body skin. The other is for a small area tactile sensor that has good sensitivity and spatial resolution, similar to human finger skin. The transducer is designed such that it is not affected by chirping and light loss. We also present the fabrication process and experimental verification of the prototype sensors. Experimental tests show that the newly designed sensors have good performance: good sensitivity, repeatability, and no-hysteresis. The load calibration is accomplished by a verified uniaxial load cell. In order to provide a more precise measurement, temperature compensation is applied to all taxels. These force sensor arrays are flexible enough to be attached to a curved surface and they also have simple wiring compared with other types of small force sensors for tactile sensation.
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paper_title: Biomimetic Tactile Sensor Array

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The performance of robotic and prosthetic hands in unstructured environments is severely limited by their having little or no tactile information compared to the rich tactile feedback of the human ...
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paper_title: A fibre-optic catheter-tip force sensor with MRI compatibility: A feasibility study

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This paper presents the development of a low-cost, Magnetic Resonance Imaging (MRI) compatible fibre-optic sensor for integration with catheters allowing the detection of contact forces between blood vessel walls and the catheter tip. Three plastic optical-fibres are aligned inside a plastic catheter in a circular pattern. A reflector is attached to a separate small part of the catheter tip, which is connected with a small deformable material to the aligned optical-fibres. In this manner a force at the catheter tip leads to a deformation of the elastic material and thus a modulation of the light yields, this is sent and received through the optical-fibres. An electronic circuit amplifies the retrieved light signal and the output voltage is used to classify the forces on the tip. The materials used are of the shelf and have a low magnetic susceptibility making this sensor fully MRI-compatible and inexpensive. Preliminary, experimental results demonstrated good force linearity in static loading and unloading conditions. The sensor was also tested in an artificial blood artery showing good dynamic response.
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paper_title: Robotic‐assisted laparoscopic radical prostatectomy

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ABSTRACT • ROBOTIC-ASSISTED radical prostatectomy uses the newest technology for surgical treatment of men with prostate cancer. Cancer of the prostate is the most common cancer in men and the second leading cause of death in American men. • THE BENEFITS of robotic-assisted prostate surgery over open radical prostatectomy include small portal incisions, decreased blood loss, and shorter hospital stays. • MAGNIFICATION of the surgeon's field of vision and jointed laparoscopic instruments that mimic the human wrist allow precision of movement and the ability to spare nerves, which result in improved postoperative urinary continence and sexual function. AORN J 84 (November 2006) 760-770. © AORN, Inc, 2006.
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paper_title: Minimally Invasive and Robotic Surgery

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Advances in surgery have focused on minimizing the invasiveness of surgical procedures, such that a significant paradigm shift has occurred for some procedures in which surgeons no longer directly touch or see the structures on which they operate. Advancements in video imaging, endoscope technology, and instrumentation have made it possible to convert many procedures in many surgical specialties from open surgeries to endoscopic ones. The use of computers and robotics promises to facilitate complex endoscopic procedures by virtue of voice control over the networked operating room, enhancement of dexterity to facilitate microscale operations, and development of virtual simulator trainers to enhance the ability to learn new complex operations. Future research will focus on delivery of diagnostic and therapeutic modalities through natural orifices in which investigation is under remote control and navigation, so that truly "noninvasive" surgery will be a reality.
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paper_title: Robot-assisted laparoscopic cholecystectomy: initial Mayo Clinic Scottsdale experience.

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OBJECTIVE ::: To review a single institution's experience with robot-assisted laparoscopic cholecystectomy. ::: ::: ::: PATIENTS AND METHODS ::: We reviewed retrospectively all cholecystectomies performed with the assistance of a surgical robot at the Mayo Clinic in Scottsdale, Ariz, from October 2002 to July 2003. Cholanglograms were obtained intraoperatively for patients with elevated results on liver function tests. The gallbladder was removed by the surgeon with the use of the robot. A surgical assistant at the operating table exchanged instruments in the robot arms and applied clips when needed. Total operating time, assembly time of the robot, complications, and postoperative course were evaluated. ::: ::: ::: RESULTS ::: Nineteen patients underwent robot-assisted laparoscopic cholecystectomy; 16 had symptomatic cholelithiasis, 2 had gallbladder polyps, and 1 had acute cholecystitis. Of the 19 surgeries, 16 were completed successfully with robotic assistance. In 3 consecutive patients, a mechanical problem occurred with the robot; however, all procedures were completed laparoscopically. The mean set-up time, including patient positioning and preparation and robotic installation, was 28.1 minutes. The mean +/- SD operating time was 82.3+/-17.9 minutes without a cholanglogram and 102+/-20.9 minutes with a cholanglogram. There were no complications and no conversions to an open procedure. ::: ::: ::: CONCLUSION ::: Robotic surgery offers many potential advantages, including surgeon comfort, elimination of surgeon tremor, improved imaging, and increased degrees of freedom of the operative Instruments, compared with conventional laparoscopic surgery. However, patient outcomes and operative costs need to be evaluated further.
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paper_title: Development of a scaled teleoperation system for nano scale interaction and manipulation

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A human-machine interface is proposed for teleoperated nano scale object interaction and manipulation. Design specifications for a bilateral scaled teleoperation system with slave and master robots, sensors, actuators, and control are discussed. Phantom and home-made haptic devices are utilized as the master manipulator, and a piezoresistive MEMS fabricated probe is selected as the slave manipulator, and topology and force sensor. A force reflecting servo type teleoperation control is chosen, and initial experiments are realized for interacting with silicon surfaces and nano structures. It is shown that fine structures can be felt on the operator's finger successfully.
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paper_title: The Use of Fiber Bragg Grating Sensors in Biomechanics and Rehabilitation Applications: The State-of-the-Art and Ongoing Research Topics

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In recent years, fiber Bragg gratings (FBGs) are becoming increasingly attractive for sensing applications in biomechanics and rehabilitation engineering due to their advantageous properties like small size, light weight, biocompatibility, chemical inertness, multiplexing capability and immunity to electromagnetic interference (EMI). They also offer a high-performance alternative to conventional technologies, either for measuring a variety of physical parameters or for performing high-sensitivity biochemical analysis. FBG-based sensors demonstrated their feasibility for specific sensing applications in aeronautic, automotive, civil engineering structure monitoring and undersea oil exploration; however, their use in the field of biomechanics and rehabilitation applications is very recent and its practicality for full-scale implementation has not yet been fully established. They could be used for detecting strain in bones, pressure mapping in orthopaedic joints, stresses in intervertebral discs, chest wall deformation, pressure distribution in Human Machine Interfaces (HMIs), forces induced by tendons and ligaments, angles between body segments during gait, and many others in dental biomechanics. This article aims to provide a comprehensive overview of all the possible applications of FBG sensing technology in biomechanics and rehabilitation and the status of ongoing researches up-to-date all over the world, demonstrating the FBG advances over other existing technologies.
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paper_title: A Modular 2-DOF Force-Sensing Instrument For Laparoscopic Surgery

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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.
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paper_title: A Miniature MRI-Compatible Fiber-optic Force Sensor Utilizing Fabry-Perot Interferometer

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Magnetic resonance imaging provides superior imaging capability because of unmatched soft tissue contrast and inherent three-dimensional visualization. Force sensing in robot-assisted systems is crucial for providing tactile feedback and measuring tissue interaction forces in needle-based percutaneous procedures in MRI. To address the issues imposed by electromagnetic compatibility in the high-field MRI and mechanical constraints due to the confined close-bore space, this paper proposes a miniaturized fiber optic force sensor utilizing Fabry-Perot interferometry. An opto-electromechanical system is designed to experimentally validate the optical model of the sensor and evaluate its sensing capability. Calibration was performed under static and dynamics loading conditions. The experimental results indicate a gage sensitivity on the order of 40 (mV/μe) of the sensor and a sensing range of 10 Newton. This sensor achieves high-resolution needle insertion force sensing in a robust and compact configuration in MRI environment.
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paper_title: A tactile sensor sheet using pressure conductive rubber with electrical-wires stitched method

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A new type of tactile sensor using pressure-conductive rubber with stitched electrical wires is presented. The sensor is thin and flexible and can cover three-dimensional objects. Since the sensor adopts a single-layer composite structure, the sensor is durable with respect to external force. In order to verify the effectiveness of this tactile sensor, we performed an experiment in which a four-fingered robot hand equipped with tactile sensors grasped sphere and column. The sensor structure, electrical circuit, and characteristics are described. The sensor control system and experimental results are also described.
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paper_title: Dynamic strain measurements by fibre Bragg grating sensor

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Abstract In this work, we describe a fibre Bragg grating (FBG) sensing system for static and dynamic strain measurements. Low cost and simple grating-based demodulation technique has been used to interrogate the strain induced Bragg wavelength shift. Experimental results showing the capability of the proposed system to perform static strain measurements with 1 μe resolution and a linear response are presented. The same system was also used for dynamic strain detection. Here, a fibre grating was bonded to a piezoceramic actuator in different configurations. A laser triangulation-based system has been used as reference measurements up to 10 kHz while dynamic strain measurements by FBG have been carried out up to 50 kHz demonstrating a dynamic resolution of ≈40 ne/Hz1/2, leading to the possibility to perform high frequency detection for on-line structural health monitoring in civil, aeronautic, and aerospace applications.
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paper_title: A fibre optic Bragg grating strain sensor for monitoring ventilatory movements

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A fibre optic Bragg grating sensor to measure the strain in the chest of patients is described. The sensor provides a new method to measure ventilatory movements and it can also determine the respiratory frequency spectrum. The apparatus uses a fixed optical filter reference scheme to reduce the overall cost and is able to detect respiratory movements with frequency components up to 10 Hz. Ventilatory signals were acquired from slow breathing, with 500 ml inspiration volume, to fast, with a reduced volume of 60 ml, respiration. The sensor described here can be used to trigger the pulse burst of electrically assisted ventilation processes or to monitor high frequency oscillatory ventilation.
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paper_title: Minimal access surgery (MAS)-related surgeon morbidity syndromes

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The benefits of minimal access surgery (MAS) in terms of accelerated recovery, reduced period of short-term disability, and patient outcome account for the widespread use of the laparoscopic approach by the majority of general surgeons. In adopting this approach with its current limitations and poor ergonomics, surgeons have been known to sustain surgery-related injuries encompassed by a spectrum best described as MAS-related surgeon morbidity syndromes, some of which are currently overlooked and poorly researched. Equivalent morbidities including the overuse syndrome (from overuse of certain muscle groups during long operations) have been documented in open surgery but are nowadays rare occurrences. As more advanced MAS operations are performed with long execution times, new patterns of neuromusculoskeletal injuries are being recognized. The surgical fatigue syndrome has also been described, though its complex nature is not fully understood. Virtually little is known on other long-term adverse effects on the surgeon following many years of operating from images displayed on a television monitor or LCD screen, and these include deterioration of visual acuity and function of the ocular muscles responsible for fixation-refixation of the eyeballs. The limited reported literature on the MAS-related surgeon morbidity syndromes identifies certain risk factors for these injuries pertaining to central and peripheral domains. Only improved knowledge of the etiology and underlying ergonomic factors based on investigative studies followed by improved instrumentation and operating room (OR) ergonomics will provide near- and long-term solutions.
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paper_title: Development of polyimide flexible tactile sensor skin

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We present the development of a polyimide-based two-dimensional tactile sensing array realized using a novel inverted fabrication technique. Thermal silicon oxide or Pyrex® substrates are treated such that their surfaces are OH group terminated, allowing good adhesion between such substrates and a spun-on polyimide film during processing through what are suspected to be hydrogen bonds that can be selectively broken when release is desired. The release of the continuous polyimide film is rapidly accomplished by breaking these bonds. This process results in robust, low-cost and continuous polymer-film devices. The developed sensor skin contains an array of membrane-based tactile sensors (taxels). Micromachined thin-film metal strain gauges are positioned on the edges of polyimide membranes. The change in resistance from each strain gauge resulting from normal forces applied to tactile bumps on the top of the membranes is used to image force distribution. Response of an individual taxel is characterized. The effective gauge factor of the taxels is found to be approximately 1.3. Sensor array output is experimentally obtained. The demonstrated devices are robust enough for direct contact with humans, everyday objects and contaminants without undue care.
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paper_title: Novel miniature MRI-compatible fiber-optic force sensor for cardiac catheterization procedures

paper_content:

This paper presents the prototype design and development of a miniature MR-compatible fiber optic force sensor suitable for the detection of force during MR-guided cardiac catheterization. The working principle is based on light intensity modulation where a fiber optic cable interrogates a reflective surface at a predefined distance inside a catheter shaft. When a force is applied to the tip of the catheter, a force sensitive structure varies the distance and the orientation of the reflective surface with reference to the optical fiber. The visual feedback from the MRI scanner can be used to determine whether or not the catheter tip is normal or tangential to the tissue surface. In both cases the light is modulated accordingly and the axial or lateral force can be estimated. The sensor exhibits adequate linear response, having a good working range, very good resolution and good sensitivity in both axial and lateral force directions. In addition, the use of low-cost and MR-compatible materials for its development makes the sensor safe for use inside MRI environments.
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paper_title: A robot with improved absolute positioning accuracy for CT guided stereotactic brain surgery

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The use of a Unimation Puma 200 robot, properly interfaced with a computerized tomographic (CT) scanner and with a probe guide mounted at its end effector for CT-guided brain tumor biopsis is discussed. Once the target is identified on the CT picture, a simple command allows the robot to move to a position such that the end-effector probe guide points toward the target. This results in a procedure faster than one using a manually adjustable frame. Probably the most important advantage, as is shown, is the improved accuracy that can be achieved by proper calibration of the robot. >
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paper_title: New tactile sensor chip with silicone rubber cover

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Abstract We report on a new tactile sensor chip developed for measuring distribution of forces on its surface. The chip has eight force-sensitive areas, called “taxel” with a pitch of 240 μm. Surface micromachining techniques are used to produce small cavities that work as pressure-sensitive capacitors. The process is CMOS compatible, therefore, on-chip switched capacitor circuits can be used for signal amplification. To enable transduction of normal forces to the sensitive areas, we cover the sensor chip surface with silicone rubber. First, measurements show that the sensor's output can be explained by results from contact mechanics. We demonstrate this by the simple case of a hard sphere pressed in the silicone rubber cover. The center of contact can be measured within 2 μm precision. The radius of the sphere and the load working on it can be estimated with high precision from the tactile sensor output data.
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paper_title: Method of correlation function for analyzing cross-sensitivity of strain and temperature in fiber grating sensors

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A novel method of correlation function for analyzing cross-sensitivity between strain and temperature is reported for the first time in this paper. Using the new method, the correlative characteristics between strain and temperature of fiber Bragg grating sensors are studied both theoretically and experimentally The experimental results accord with the theoretical calculations.
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paper_title: Efficacy of the Da Vinci surgical system in abdominal surgery compared with that of laparoscopy: a systematic review and meta-analysis.

paper_content:

Aim:The main aim of this review was to compare the safety and efficacy of the Da Vinci Surgical System (DVSS) and conventional laparoscopic surgery (CLS) in different types of abdominal intervention.Summary of Background Data:DVSS is an emerging laparoscopic technology. The surgeon directs the robot
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paper_title: Miniature fiber-optic force sensor based on low-coherence Fabry-Pérot interferometry for vitreoretinal microsurgery

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During vitreoretinal surgery, the surgeon manipulates retinal tissue with tool-to-tissue interaction forces below the human sensory threshold. A force sensor (FS) integrated with conventional surgical tools may significantly improve the surgery outcome by providing tactile feedback to the surgeon. We designed and built a surgical tool integrated with a miniature FS with an outer diameter smaller than 1 mm for vitreoretinal surgery based on low-coherence Fabry–Perot (FP) interferometry. The force sensing elements are located at the tool tip which is in direct contact with tissue during surgery and the FP cavity length is interrogated by a fiber-optic common-path phase-sensitive optical coherence tomography (OCT) system. We have calibrated the FS's response to axial and lateral forces and conducted experiments to verify that our FS can simultaneously measure both axial and lateral force components.
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paper_title: Navigating inner space: 3-D assistance for minimally invasive surgery

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Abstract Since its inception about three decades ago, modern minimally invasive surgery has made huge advances in both technique and technology. However, the minimally invasive surgeon is still faced with daunting challenges in terms of visualization and hand-eye coordination. At the Center for Computer Integrated Surgical Systems and Technology (CISST) we have been developing a set of techniques for assisting surgeons in navigating and manipulating the three-dimensional space within the human body. In order to develop such systems, a variety of challenging visual tracking, reconstruction and registration problems must be solved. In addition, this information must be tied to methods for assistance that improve surgical accuracy and reliability but allow the surgeon to retain ultimate control of the procedure and do not prolong time in the operating room. In this article, we present two problem areas, eye microsurgery and thoracic minimally invasive surgery, where computational vision can play a role. We then describe methods we have developed to process video images for relevant geometric information, and related control algorithms for providing interactive assistance. Finally, we present results from implemented systems.
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paper_title: Computer-Controlled Motorized Endoscopic Grasper for In Vivo Measurement of Soft Tissue Biomechanical Characteristics

paper_content:

Accurate biomechanical characteristics of tissues are essential for developing realistic virtual reality surgical simulators utilizing haptic devices. Surgical simulation technology has progressed rapidly but without a large database of soft tissue mechanical properties with which to incorporate. The device described here is a computer-controlled, motorized endoscopic grasper capable of applying surgically relevant levels of force to tissue in vivo and measuring the tissue's force-deformation properties.
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paper_title: A new MRI-compatible optical fiber tactile sensor for use in minimally invasive robotic surgery systems

paper_content:

In conventional open surgery, using finger palpation, surgeons can distinguish between different types of tissues. ::: However, in the current commercially available minimally invasive robotic surgery (MIRS) systems, direct tactile ::: feedback is negligible. In the present paper, based on a novel concept, a new bend-type optical fiber tactile sensor is ::: proposed, designed, simulated, fabricated, and tested. In both dynamic and static loading conditions, the proposed tactile ::: sensor measures forces interacting between tissues and surgical tools whether they are distributed contact forces or ::: concentrated contact forces, or even if these forces are in combination. As a result, the sensor can identify the size and ::: the position of blood vessels or of abnormal tissues, one of which could be a tumorous lump within normal tissues. In ::: addition, the static force measurement provided by the sensor allows surgeons to maintain contact stability in any static ::: interactions between surgical tools and tissues while at the same time avoiding tissue damage because of excessive ::: contact force. In the meantime, because the sensor is based uniquely on optical fibers, it is insensitive to electromagnetic ::: fields. As a result, it is compatible with Magnetic Resonance Imaging (MRI) devices, which are currently in widespread ::: use in surgical operating rooms.
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paper_title: Real-time MRI-guided needle placement robot with integrated fiber optic force sensing

paper_content:

This paper presents the first prototype of a magnetic resonance imaging (MRI) compatible piezoelectric actuated robot integrated with a high-resolution fiber optic sensor for prostate brachytherapy with real-time in situ needle steering capability in 3T MRI. The 6-degrees-of-freedom (DOF) robot consists of a modular 3-DOF needle driver with fiducial tracking frame and a 3-DOF actuated Cartesian stage. The needle driver provides needle cannula rotation and translation (2-DOF) and stylet translation (1-DOF). The driver mimics the manual physician gesture by two point grasping. To render proprioception associated with prostate interventions, a Fabry-Perot interferometer based fiber optic strain sensor is designed to provide high-resolution axial needle insertion force measurement and is robust to large range of temperature variation. The paper explains the robot mechanism, controller design, optical modeling and opto-mechanical design of the force sensor. MRI compatibility of the robot is evaluated under 3T MRI using standard prostate imaging sequences and average signal noise ratio (SNR) loss is limited to 2% during actuator motion. A dynamic needle insertion is performed and bevel tip needle steering capability is demonstrated under continuous real-time MRI guidance, both with no visually identifiable interference during robot motion. Fiber optic sensor calibration validates the theoretical modeling with satisfactory sensing range and resolution for prostate intervention.
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paper_title: MRI-Compatible Fiber-Optic Force Sensors for Catheterization Procedures

paper_content:

Cardiac catheterization is an interventional procedure that is usually carried out without the use of force sensors. During such procedures the physician mainly relies on visual feedback provided by an imaging modality, like X-ray fluoroscopy, Computed Tomography (CT) or Magnetic Resonance Imaging (MRI). Hence, the physician it is not always able to predict the forces between the catheter and blood vessel walls. Sometimes, tasks such as moving a catheter through delicate blood vessel networks and through the heart chambers become difficult. This paper provides an overview of fiber-optic pressure and force sensors for cardiac catheters with potential for providing haptic feedback. In conjunction with an MRI scanner the overall cardiac catheterization procedure could be enhanced. The paper focuses on fiber-optic sensors due to their very good MRI compatibility. Background information on manual and robotic catheterization approaches is provided together with an analytic discussion of the current state-of-the-art in fiber-optic force and pressure sensors for catheters, which can provide haptic information.
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paper_title: Fiber grating sensors in medicine: Current and emerging applications

paper_content:

Fiber grating sensors hold immense potential for biomedical applications due to their inherent properties like small size, biocompatibility, non-toxicity, chemical inertness and electromagnetically inert nature. Grating based sensors are well known technology for structural health monitoring (SHM) in the arena of civil and aerospace; however investigations for their use in the field of medicine are fairly recent and they have not been yet commercialized for the same. As these sensors detect strain, temperature, pressure, vibration, curvature and refractive index of the surrounding material even in high magnetic and electric field environments, they can serve diagnostic purposes in diverse areas of healthcare e.g. biomechanics, cardiology, gynecology, very low temperature monitoring and immunosensing to name a few. Most importantly, they can be used efficiently for thermal and pressure mapping even during MRI procedure where conventional sensors may fail. The paper is a review of various application areas of fiber grating based devices, the status of precedent and ongoing research around the world, and discussion on the issues hampering their rapid growth in the field.
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paper_title: Fiber grating sensors

paper_content:

We review the recent developments in the area of optical fiber grating sensors, including quasi-distributed strain sensing using Bragg gratings, systems based on chirped gratings, intragrating sensing concepts, long period-based grating sensors, fiber grating laser-based systems, and interferometric sensor systems based on grating reflectors.
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paper_title: Surgical Forces and Tactile Perception During Retinal Microsurgery

paper_content:

Purpose: Vitreoretinal surgery involves the manipulation of delicate retinal membranes with a required surgical accuracy often on the order of tens of microns, a scale at or near the limit of human positional ability. In addition, forces imposed by the tissue on the surgical cool are exceedingly small. Here we investigate the magnitude of forces generated during retinal surgery in cadaveric porcine eyes and compare the results with the magnitude of forces discernable by retinal surgeons. This data will be used as a design guideline for robotic surgical augmentation systems currently under development Methods: The study was performed in two phases. First, retinal surgeons manipulated the retina of porcine cadaver eyes with a calibrated 1-axis force sensing retinal pick while data was simultaneously recorded. In the second phase, blindfolded subjects held the pick and were instructed to press a button whenever an “event” was felt. Events were generated by slowly tapping the end of the pick with varying force while both the magnitudes of forces applied and the responses of the subjects we recorded. The magnitudes of forces generated during retinal surgery were then compared with those that could be discerned by the subjects. Results: Roughly 75% of all forces measured during retinal microsurgery were found to be less than 7.5 mN in magnitude, however only 19.3 ± 8.1% (N=492) of events generated at this level could be felt by the subjects. Conclusions: The results of this study indicate that a majority of retinal surgery is probably performed without the surgeon being able to “feel” interactions between retinal tissue and the surgical tool. Prior studies have indicated that relying on visual feedback alone increases the length of manual manipulation tasks and reduces task accuracy. The lack of tactile sensation during retinal surgery similarly could adversely affect surgical outcome.
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paper_title: Micro-force Sensing in Robot Assisted Membrane Peeling for Vitreoretinal Surgery

paper_content:

Vitreoretinal surgeons use 0.5mm diameter instruments to manipulate delicate tissue inside the eye while applying imperceptible forces that can cause damage to the retina. We present a system which robotically regulates user-applied forces to the tissue, to minimize the risk of retinal hemorrhage or tear during membrane peeling, a common task in vitreoretinal surgery. Our research platform is based on a cooperatively controlled microsurgery robot. It integrates a custom micro-force sensing surgical pick, which provides conventional surgical function and real time force information. We report the development of a new phantom, which is used to assess robot control, force feedback methods, and our newly implemented auditory sensory substitution to specifically assist membrane peeling. Our findings show that auditory sensory substitution decreased peeling forces in all tests, and that robotic force scaling with audio feedback is the most promising aid in reducing peeling forces and task completion time.
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paper_title: Integrating optical fiber force sensors into microforceps for ORL microsurgery

paper_content:

The delicate anatomy of the ear require surgeons to use great care when operating on its internal structures. One example for such an intervention is the stapedectomy, where a small crook shaped piston is placed in the oval window of the cochlea and connected to the incus through crimping thus bypassing the diseased stapes. Performing the crimp process with the correct force is necessary since loose crimps poorly transmit sound whereas tight crimps will eventually result in necrosis of the incus. Clinically, demand is high to reproducibly conduct the crimp process through a precise force measurement. For this reason, we have developed a fiber Bragg grating (FBG) integrated microforceps for use in such interventions. This device was calibrated, and tested in cadaver preparations. With this instrument we were able to measure for the first time forces involved in crimping a stapes prosthesis to the incus. We also discuss a method of attaching and actuating such forceps in conjunction with a robot currently under development in our group. Each component of this system can be used separately or combined to improve surgical accuracy, confidence and outcome.
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paper_title: The chick embryo chorioallantoic membrane as a model for in vivo research on angiogenesis.

paper_content:

The chick embryo chorioallantoic membrane (CAM) is an extraembryonic membrane that is commonly used in vivo to study both new vessel formation and its inhibition in response to tissues, cells, or soluble factors. Quantitative or semiquantitative methods may be used to evaluate the amount of angiogenesis and anti-angiogenesis. Thanks to the CAM system, angiogenesis could be investigated in association with normal, inflammatory and tumor tissues, and soluble factors inducing angiogenic or anti-angiogenic effects could be identified. Rabbit cornea provides an alternative in vivo system, but CAM appears to be easier to handle and less expensive. Moreover, CAM can be used with very few limitations.
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paper_title: A sub-millimetric, 0.25 mN resolution fully integrated fiber-optic force-sensing tool for retinal microsurgery

paper_content:

Purpose ::: Retinal microsurgery requires extremely delicate manipulation of retinal tissue where tool-to-tissue interaction forces are usually below the threshold of human perception. Creating a force-sensing surgical instrument that measures the forces directly at the tool tip poses great challenges due to the interactions between the tool shaft and the sclerotomy opening.
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paper_title: Force sensing micro-forceps for robot assisted retinal surgery

paper_content:

Membrane peeling is a standard vitreoretinal procedure, where the surgeon delaminates a very thin membrane from retina surface using surgical picks and forceps. This requires extremely delicate manipulation of the retinal tissue. Applying excessive forces during the surgery can cause serious complications leading to vision loss. For successful membrane peeling, most of the applied forces need to be very small, well below the human tactile sensation threshold. In this paper, we present a robotic system that combines a force sensing forceps tool and a cooperatively-controlled surgical robot. This combination allows us to measure the forces directly at the tool tip and use this information for limiting the applied forces on the retina. This may prevent many iatrogenic injuries and allow safer maneuvers during vitreoretinal procedures. We show that our system can successfully eliminate hand-tremor and excessive forces in membrane peeling experiments on the inner shell membrane of a chicken embryo.
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paper_title: Development and Application of a New Steady-Hand Manipulator for Retinal Surgery

paper_content:

This paper describes the development and initial testing of a new and optimized version of a steady-hand manipulator for retinal microsurgery. In the steady-hand paradigm, the surgeon and the robot share control of a tool attached to the robot through a force sensor. The robot controller senses forces exerted by the operator on the tool and uses this information in various control modes to provide smooth, tremor-free, precise positional control and force scaling. The steady-hand manipulator reported here has been specifically designed with the unique constraints of retinal microsurgery in mind. In particular, the system makes use of a compact wrist design that places the bulk of the robot away from the operating field. The resulting system has high efficacy, flexibility and ergonomics while meeting the accuracy and safety requirements of microsurgery. We have now tested this robot on a biological model system and we report a protocol for reliably cannulating ~80 mum OD veins (the size of veins in the human retina) using the system
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paper_title: Toward Active Tremor Canceling in Handheld Microsurgical Instruments

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This paper describes research in active instruments for enhanced accuracy in microsurgery. The aim is to make accuracy enhancement as transparent to the surgeon as possible. Rather than using a robotic arm, we have taken the novel approach of developing a handheld instrument that senses its own movement, distinguishes between desired and undesired motion, and deflects its tip to perform active compensation of the undesired component. The research has therefore required work in quantification and modeling of instrument motion, filtering algorithms for tremor and other erroneous movements, and development of handheld electromechanical systems to perform active error compensation. The paper introduces the systems developed in this research and presents preliminary results.
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paper_title: New steady-hand Eye Robot with micro-force sensing for vitreoretinal surgery

paper_content:

In retinal microsurgery, surgeons are required to perform micron scale maneuvers while safely applying forces to the retinal tissue that are below sensory perception. Real-time characterization and precise manipulation of this delicate tissue has thus far been hindered by human limits on tool control and the lack of a surgically compatible endpoint sensing instrument. Here we present the design of a new generation, cooperatively controlled microsurgery robot with a remote center-of-motion (RCM) mechanism and an integrated custom micro-force sensing surgical hook. Utilizing the forces measured by the end effector, we correct for tool deflections and implement a micro-force guided cooperative control algorithm to actively guide the operator. Preliminary experiments have been carried out to test our new control methods on raw chicken egg inner shell membranes and to capture useful dynamic characteristics associated with delicate tissue manipulations.
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paper_title: Novel Contact Force Sensor Incorporated in Irrigated Radiofrequency Ablation Catheter Predicts Lesion Size and Incidence of Steam Pop and Thrombus

paper_content:

Background— An open-irrigated radiofrequency (RF) ablation catheter was developed to measure contact force (CF). Three optical fibers measure microdeformation of the catheter tip. The purpose of this study was to (1) validate the accuracy of CF sensor (CFS) (bench test); and (2) determine the relationship between CF and tissue temperatures, lesion size, steam pop, and thrombus during RF ablation using a canine thigh muscle preparation. ::: ::: Methods and Results— CFS measurements (total 1409) from 2 catheters in 3 angles (perpendicular, parallel, and 45°) were compared with a certified balance (range, 0 to 50 g). CFS measurements correlated highly ( R 2≥0.988; mean error, ≤1.0 g). In 10 anesthetized dogs, a skin cradle over the thigh muscle was superfused with heparinized blood at 37°C. A 7F catheter with 3.5-mm saline-irrigated electrode and CFS (Endosense) was held perpendicular to the muscle at CF of 2, 10, 20, 30, and 40 g. RF was delivered (n=100) for 60 seconds at 30 or 50 W (irrigation 17 or 30 mL/min). Tissue temperature (3 and 7 mm depths), lesion size, thrombus, and steam pop increased significantly with increasing CF at each RF power. Lesion size was greater with applications of lower power (30 W) and greater CF (30 to 40 g) than at high power (50 W) with lower CF (2 to 10 g). ::: ::: Conclusions— This novel ablation catheter, which accurately measures CF, confirmed CF is a major determinant of RF lesion size. Steam pop and thrombus incidence also increases with CF. CFS in an open-irrigated ablation catheter that may optimize the selection of RF power and application time to maximize lesion formation and reduce the risk of steam pop and thrombus. ::: ::: Received July 10, 2008; accepted October 6, 2008. ::: ::: # CLINICAL PERSPECTIVE {#article-title-2}
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paper_title: Temperature Sensor Array for Tactile Sensation Using FBG Sensors

paper_content:

This paper describes a tactile sensor system which can detect distributed temperature and distributed force using a fiber Bragg grating (FBG) sensor. The newly designed temperature sensor using FBG is introduced and the performance of this temperature sensor is evaluated. Combining this temperature sensor array with the force sensor array, a new tactile sensor system capable of measuring a temperature distribution and a force distribution is evaluated. In particular, through the use of the distributed temperature sensor array, the distributed force sensor array can be compensated for a temperature effect that prevents an accurate distributed force measurement.
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paper_title: Discretely Loaded Beam-Type Optical Fiber Tactile Sensor for Tissue Manipulation and Palpation in Minimally Invasive Robotic Surgery

paper_content:

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.
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paper_title: FEM analysis of predicting electrode-myocardium contact from RF cardiac catheter ablation system impedance

paper_content:

We used the finite-element method (FEM) to model and analyze the resistance between the catheter tip electrode and the dispersive electrode during radio-frequency cardiac catheter ablation for the prediction of myocardium-electrode contact. We included deformation of the myocardial surface to achieve accurate modeling. For perpendicular catheter contact, we measured the side view of myocardial deformation using X-ray projection imaging. We averaged the deformation contour from nine samples, and then incorporated the contour information into our FEM model. We measured the resistivity of the bovine myocardium using the four-electrode method, and then calculated the resistance change as the catheter penetrated into the myocardium. The FEM result of resistance versus catheter penetration depth matches well with our experimental data.
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paper_title: Potential of intracardiac ultrasonography as an adjunct for mapping and ablation.

paper_content:

Radio frequency catheter ablation of cardiac tissues has evolved rapidly as the standard therapy for various arrhythmias. Current mapping techniques include fluoroscopy and endocardial ECG recordings. These techniques are time-consuming and give only limited information with regard to cardiac anatomy and pathology. Moreover, fluoroscopy leads to significant radiation exposure to the patient and the operator. Intracardiac ultrasonography is a promising new technique that may improve intracardiac anatomic orientation, reduce radiation exposure, allow better control of lesion formation during radio frequency current application, and identify possible complications such as thrombus formation or perforation. Intracardiac ultrasonography systems that are presently available are limited by insufficient penetration depth and image resolution. Technical refinements are discussed that may improve the applicability of intracardiac echocardiography for electrophysiologic mapping procedures.
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paper_title: Three-dimensional finite element analysis of current density and temperature distributions during radio-frequency ablation

paper_content:

This study analyzed the influence of electrode geometry, tissue-electrode angle, and blood flow on current density and temperature distribution, lesion size, and power requirements during radio-frequency ablation. The authors used validated three-dimensional finite element models to perform these analyses. They found that the use of an electrically insulating layer over the junction between electrode and catheter body reduced the chances of charring and coagulation. The use of a thermistor at the tip of the ablation electrodes did not affect the current density distribution. For longer electrodes, the lateral current density decreased more slowly with distance from the electrode surface. The authors analyzed the effects of three tissue-electrode angles: 0, 45, and 90/spl deg/. More power was needed to reach a maximal tissue temperature of 95/spl deg/C after 120 s when the electrode-tissue angle was 45/spl deg/. Consequently, the lesions were larger and deeper for a tissue-electrode angle of 45/spl deg/ than for 0 and 90/spl deg/. The lesion depth, volume, and required power increased with blood flow rate regardless of the tissue-electrode angle. The significant changes in power with the tissue-electrode angle suggest that it is safer and more efficient to ablate using temperature-controlled RF generators. The maximal temperature was reached at locations within the tissue, a fraction of a millimeter away from the electrode surface. These locations did not always coincide with the local current density maxima. The locations of these hottest spots and the difference between their temperature and the temperature read by a sensor placed at the electrode tip changed with blood flow rate and tissue-electrode angle. >
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paper_title: Tactile sensor arrays using fiber Bragg grating sensors

paper_content:

This paper describes two kinds of 3 × 3 force sensor arrays using fiber Bragg gratings (FBG) and transducers for tactile sensation to detect a distributed normal force. One array is developed for a large area tactile sensor that has good sensitivity but low spatial resolution, similar to human body skin. The other is for a small area tactile sensor that has good sensitivity and spatial resolution, similar to human finger skin. The transducer is designed such that it is not affected by chirping and light loss. We also present the fabrication process and experimental verification of the prototype sensors. Experimental tests show that the newly designed sensors have good performance: good sensitivity, repeatability, and no-hysteresis. The load calibration is accomplished by a verified uniaxial load cell. In order to provide a more precise measurement, temperature compensation is applied to all taxels. These force sensor arrays are flexible enough to be attached to a curved surface and they also have simple wiring compared with other types of small force sensors for tactile sensation.
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paper_title: Contact Geometry Affects Lesion Formation in Radio-Frequency Cardiac Catheter Ablation

paper_content:

One factor which may be important for determining proper lesion creation during atrial ablation is catheter-endocardial contact. Little information is available that relates geometric contact, depth and angle, to ablation lesion formation. We present an electrothermal computer model of ablation that calculated lesion volume and temperature development over time. The Pennes bioheat equation was coupled to a quasistatic electrical problem to investigate the effect of catheter penetration depth, as well as incident catheter angle as may occur in practice. Biological experiments were performed to verify the modelling of electrical phenomena. Results show that for deeply penetrating tips, acute catheter angles reduced the rate of temperature buildup, allowing larger lesions to form before temperatures elevated excessively. It was also found that greater penetration did not lead to greater transmurality of lesions. We conclude that catheter contact angle plays a significant role in lesion formation, and the time course must be considered. This is clinically relevant because proper identification and prediction of geometric contact variables could improve ablation efficacy.
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paper_title: Force Sensing Robot Fingers using Embedded Fiber Bragg Grating Sensors and Shape Deposition Manufacturing

paper_content:

Force sensing is an essential requirement for dexterous robot manipulation. Although strain gages have been widely used, a new sensing approach is desirable for applications that require greater robustness, design flexibility and immunity to electromagnetic noise. An exoskeletal force sensing robot finger was developed by embedding fiber Bragg grating (FBG) sensors into a polymer-based structure. Multiple FBG sensors were embedded into the structure to allow the manipulator to sense and measure both contact forces and grasping forces. In order to fabricate a three-dimensional structure, a new shape deposition manufacturing (SDM) process was explored. The sensorized SDM-fabricated finger was then characterized using an FBG interrogator. A force localization scheme is also described
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paper_title: Real time assessment of RF cardiac tissue ablation with optical spectroscopy

paper_content:

An optical spectroscopy approach is demonstrated allowing for critical parameters during RF ablation of cardiac tissue to be evaluated in real time. The method is based on incorporating in a typical ablation catheter transmitting and receiving fibers that terminate at the tip of the catheter. By analyzing the spectral characteristics of the NIR diffusely reflected light, information is obtained on such parameters as, contact of catheter with the tissue, lesion formation, depth of penetration of the lesion, formation of char and coagulum during the ablation.
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paper_title: Exoskeletal Force-Sensing End-Effectors With Embedded Optical Fiber-Bragg-Grating Sensors

paper_content:

Force sensing is an essential requirement for dexterous robot manipulation. We describe composite robot end-effectors that incorporate optical fibers for accurate force sensing and estimation of contact locations. The design is inspired by the sensors in arthropod exoskeletons that allow them to detect contacts and loads on their limbs. In this paper, we present a fabrication process that allows us to create hollow multimaterial structures with embedded fibers and the results of experiments to characterize the sensors and controlling contact forces in a system involving an industrial robot and a two-fingered dexterous hand. We also briefly describe the optical-interrogation method used to measure multiple sensors along a single fiber at kilohertz rates for closed-loop force control.
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paper_title: Surgical Forces and Tactile Perception During Retinal Microsurgery

paper_content:

Purpose: Vitreoretinal surgery involves the manipulation of delicate retinal membranes with a required surgical accuracy often on the order of tens of microns, a scale at or near the limit of human positional ability. In addition, forces imposed by the tissue on the surgical cool are exceedingly small. Here we investigate the magnitude of forces generated during retinal surgery in cadaveric porcine eyes and compare the results with the magnitude of forces discernable by retinal surgeons. This data will be used as a design guideline for robotic surgical augmentation systems currently under development Methods: The study was performed in two phases. First, retinal surgeons manipulated the retina of porcine cadaver eyes with a calibrated 1-axis force sensing retinal pick while data was simultaneously recorded. In the second phase, blindfolded subjects held the pick and were instructed to press a button whenever an “event” was felt. Events were generated by slowly tapping the end of the pick with varying force while both the magnitudes of forces applied and the responses of the subjects we recorded. The magnitudes of forces generated during retinal surgery were then compared with those that could be discerned by the subjects. Results: Roughly 75% of all forces measured during retinal microsurgery were found to be less than 7.5 mN in magnitude, however only 19.3 ± 8.1% (N=492) of events generated at this level could be felt by the subjects. Conclusions: The results of this study indicate that a majority of retinal surgery is probably performed without the surgeon being able to “feel” interactions between retinal tissue and the surgical tool. Prior studies have indicated that relying on visual feedback alone increases the length of manual manipulation tasks and reduces task accuracy. The lack of tactile sensation during retinal surgery similarly could adversely affect surgical outcome.
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paper_title: Micro-force Sensing in Robot Assisted Membrane Peeling for Vitreoretinal Surgery

paper_content:

Vitreoretinal surgeons use 0.5mm diameter instruments to manipulate delicate tissue inside the eye while applying imperceptible forces that can cause damage to the retina. We present a system which robotically regulates user-applied forces to the tissue, to minimize the risk of retinal hemorrhage or tear during membrane peeling, a common task in vitreoretinal surgery. Our research platform is based on a cooperatively controlled microsurgery robot. It integrates a custom micro-force sensing surgical pick, which provides conventional surgical function and real time force information. We report the development of a new phantom, which is used to assess robot control, force feedback methods, and our newly implemented auditory sensory substitution to specifically assist membrane peeling. Our findings show that auditory sensory substitution decreased peeling forces in all tests, and that robotic force scaling with audio feedback is the most promising aid in reducing peeling forces and task completion time.
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paper_title: A sub-millimetric, 0.25 mN resolution fully integrated fiber-optic force-sensing tool for retinal microsurgery

paper_content:

Purpose ::: Retinal microsurgery requires extremely delicate manipulation of retinal tissue where tool-to-tissue interaction forces are usually below the threshold of human perception. Creating a force-sensing surgical instrument that measures the forces directly at the tool tip poses great challenges due to the interactions between the tool shaft and the sclerotomy opening.
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paper_title: Force sensing micro-forceps for robot assisted retinal surgery

paper_content:

Membrane peeling is a standard vitreoretinal procedure, where the surgeon delaminates a very thin membrane from retina surface using surgical picks and forceps. This requires extremely delicate manipulation of the retinal tissue. Applying excessive forces during the surgery can cause serious complications leading to vision loss. For successful membrane peeling, most of the applied forces need to be very small, well below the human tactile sensation threshold. In this paper, we present a robotic system that combines a force sensing forceps tool and a cooperatively-controlled surgical robot. This combination allows us to measure the forces directly at the tool tip and use this information for limiting the applied forces on the retina. This may prevent many iatrogenic injuries and allow safer maneuvers during vitreoretinal procedures. We show that our system can successfully eliminate hand-tremor and excessive forces in membrane peeling experiments on the inner shell membrane of a chicken embryo.
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paper_title: Development and preliminary data of novel integrated optical micro-force sensing tools for retinal microsurgery

paper_content:

This paper reports the development of novel micro-force sensing tools for retinal microsurgery. Retinal microsurgery requires extremely delicate manipulation of retinal tissue, and tool-to-tissue interaction forces are frequently below human perceptual thresholds. Further, the interaction between the tool shaft and sclera makes accurate sensing of forces exerted on the retina very difficult with previously developed force sensing schemes, in which the sensor is located outside the eye. In the work reported here, we incorporate 160 µm Fiber Bragg Grating (FBG) strain sensors into the tool shaft to sense forces distal to the sclera. The sensor is applicable both with robotically manipulated and freehand tools. Preliminary results with a 1 degree-of-freedom (DOF) sensor have demonstrated 0.25 mN resolution, and work is underway to develop 2 and 3 DOF tools. The design and analysis of the force sensing tool is presented with preliminary testing data and some initial experiments using the tool with both freehand and robotic manipulation.
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paper_title: FBG Sensor for Contact Level Monitoring and Prediction of Perforation in Cardiac Ablation

paper_content:

Atrial fibrillation (AF) is the most common type of arrhythmia, and is characterized by a disordered contractile activity of the atria (top chambers of the heart). A popular treatment for AF is radiofrequency (RF) ablation. In about 2.4% of cardiac RF ablation procedures, the catheter is accidently pushed through the heart wall due to the application of excessive force. Despite the various capabilities of currently available technology, there has yet to be any data establishing how cardiac perforation can be reliably predicted. Thus, two new FBG based sensor prototypes were developed to monitor contact levels and predict perforation. Two live sheep were utilized during the study. It was observed during operation that peaks appeared in rhythm with the heart rate whenever firm contact was made between the sensor and the endocardial wall. The magnitude of these peaks varied with pressure applied by the operator. Lastly, transmural perforation of the left atrial wall was characterized by a visible loading phase and a rapid signal drop-off correlating to perforation. A possible pre-perforation signal was observed for the epoxy-based sensor in the form of a slight signal reversal (12–26% of loading phase magnitude) prior to perforation (occurring over 8 s).
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paper_title: New steady-hand Eye Robot with micro-force sensing for vitreoretinal surgery

paper_content:

In retinal microsurgery, surgeons are required to perform micron scale maneuvers while safely applying forces to the retinal tissue that are below sensory perception. Real-time characterization and precise manipulation of this delicate tissue has thus far been hindered by human limits on tool control and the lack of a surgically compatible endpoint sensing instrument. Here we present the design of a new generation, cooperatively controlled microsurgery robot with a remote center-of-motion (RCM) mechanism and an integrated custom micro-force sensing surgical hook. Utilizing the forces measured by the end effector, we correct for tool deflections and implement a micro-force guided cooperative control algorithm to actively guide the operator. Preliminary experiments have been carried out to test our new control methods on raw chicken egg inner shell membranes and to capture useful dynamic characteristics associated with delicate tissue manipulations.
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Title: Advances in Bio-Tactile Sensors for Minimally Invasive Surgery Using the Fibre Bragg Grating Force Sensor Technique: A Survey

Section 1: Introduction
Description 1: Provide an overview of minimally invasive surgery (MIS), its advantages, and the challenges including the need for tactile feedback. Discuss advances in robotics and optical fibre-based sensors, especially Fibre Bragg Grating (FBG) sensors.

Section 2: FBG Working and Sensing Principle
Description 2: Explain the working principle of Fibre Bragg Grating sensors including the physical principles that underlie the technology, and how changes in strain and temperature affect the sensor readings.

Section 3: Tactile Sensor Types
Description 3: Introduce various types of tactile sensors used in MIS, categorizing them into single-point and tactile array sensors. 

Section 4: Single-Point FBG Tactile Sensors
Description 4: Discuss single-point FBG tactile sensors, including different configurations such as 1-DOF and 2-DOF designs, and their applications in microsurgery.

Section 5: Catheterisation Applications
Description 5: Explore the use of FBG tactile sensors in catheterisation, particularly in procedures like radiofrequency ablation for treating cardiac diseases. Review specific studies and their outcomes.

Section 6: FBGs in Minimally Invasive Treatments and Biopsy Applications: Shaping Sensing
Description 6: Examine the use of FBG sensors in biopsy applications and minimally invasive treatments, focusing on their capability to provide tactile information and ensure precise tool manipulation.

Section 7: Conclusions
Description 7: Summarize the findings of the survey, discussing the benefits and challenges associated with FBG tactile sensors in MIS. Highlight future perspectives for research and potential improvements.