Development and preliminary results of bimanual smart micro-surgical system using a ball-lens coupled OCT distance sensor

Bimanual surgery enhances surgical effectiveness and is required to successfully accomplish complex microsurgical tasks. The essential advantage is the ability to simultaneously grasp tissue with one hand to provide counter traction or exposure, while dissecting with the other. Towards enhancing the precision and safety of bimanual microsurgery we present a bimanual SMART micro-surgical system for a preliminary ex-vivo study. To the best of our knowledge, this is the first demonstration of a handheld bimanual microsurgical system. The essential components include a ball-lens coupled common-path swept source optical coherence tomography sensor. This system effectively suppresses asynchronous hand tremor using two PZT motors in feedback control loop and efficiently assists ambidextrous tasks. It allows precise bimanual dissection of biological tissues with a reduction in operating time as compared to the same tasks performed with conventional onehanded approaches. © 2016 Optical Society of America.1

From teleoperation to autonomous robot-assisted microsurgery: A survey

Robot-assisted microsurgery (RAMS) has many benefits compared to traditional microsurgery. Microsurgical platforms with advanced control strategies, high-quality micro-imaging modalities and micro-sensing systems are worth developing to further enhance the clinical outcomes of RAMS. Within only a few decades, microsurgical robotics has evolved into a rapidly developing research field with increasing attention all over the world. Despite the appreciated benefits, significant challenges remain to be solved. In this review paper, the emerging concepts and achievements of RAMS will be presented. We introduce the development tendency of RAMS from teleoperation to autonomous systems. We highlight the upcoming new research opportunities that require joint efforts from both clinicians and engineers to pursue further outcomes for RAMS in years to come

Miniature fiber-optic force sensor based on low-coherence Fabry-Pérot interferometry for vitreoretinal microsurgery

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–Pérot (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

Optical Coherence Tomography Distal Sensor Based Handheld Microsurgical Tools

Microsurgery is typically differentiated from a general surgery in that it requires a precise sub-millimeter manipulation that could only be achievable under optical magnification. For instance, microsurgeons use surgical microscopes to view surgical sites and train themselves several years to acquire surgical skills to perform the delicate procedures. However, such microsurgical approach imposes considerable physical stress and mental fatigue on the surgeons and these could be sources for surgical risks and complications. For these reasons, a variety of robotic based surgical guidance methods have been developed and studied with the hope of providing safer and more precise microsurgery. These robotic arm based systems have been developed to provide precise tool movement and to remove physiological hand tremor, which is one of the main limiting factors that prevents precise tool manipulation. In another approaches use simpler system that adds robotic functions to existing handheld surgical tools. It is a hybrid system that incorporates the advantages of conventional manual system and robot-assist system. The advantages of such hybrid handheld systems include portability, disposability, and elimination of the large robotic-assist systems in complex surgical environment. The most critical benefit of the hybrid handheld system is its ease of use since it allows surgeons to manipulate tools mostly using their hand. However due to the imprecise nature of tool control using hands, tool tracking is more critical in handheld microsurgical tool systems than that of robotic arm systems. In general, the accuracy of the tool control is largely determined by the resolution of the sensors and the actuators. Therefore, it is essential to develop a real-time high resolution sensor in order to develop a practical microsurgical tools. For this reason, a novel intuitive targeting and tracking scheme that utilizes a common-path swept source optical coherence tomography (CP-SSOCT) distal sensor was developed integrated with handheld microsurgical tools. To achieve micron-order precision control, a reliable and accurate OCT distal sensing method was developed. The method uses a prediction algorithm is necessary to compensate for the system delay associated with the computational, mechanical and electronic latencies. Due to the multi-layered structure of retina, it was also necessary to develop effective surface detection methods rather than simple peak detection. The OCT distal sensor was integrated into handheld motion-guided micro-forceps system for highly accurate depth controlled epiretinal membranectomy. A touch sensor and two motors were used in the forceps design to minimize the motion artifact induced by squeezing, and to independently control the depth guidance of the tool-tip and the grasping action. We also built a depth guided micro-injector system that enables micro-injection with precise injection depth control. For these applications, a smart motion monitoring and a guiding algorithm were developed to provide precise and intuitive freehand control. Finally, phantom and ex-vivo bovine eye experiments were performed to evaluate the performance of the proposed OCT distal sensor and validate the effectiveness of the depth-guided micro-forceps and micro-injector over the freehand performance

Augmentation Of Human Skill In Microsurgery

Surgeons performing highly skilled microsurgery tasks can benefit from information and manual assistance to overcome technological and physiological limitations to make surgery safer, efficient, and more successful. Vitreoretinal surgery is particularly difficult due to inherent micro-scale and fragility of human eye anatomy. Additionally, surgeons are challenged by physiological hand tremor, poor visualization, lack of force sensing, and significant cognitive load while executing high-risk procedures inside the eye, such as epiretinal membrane peeling. This dissertation presents the architecture and the design principles for a surgical augmentation environment which is used to develop innovative functionality to address the fundamental limitations in vitreoretinal surgery. It is an inherently information driven modular system incorporating robotics, sensors, and multimedia components. The integrated nature of the system is leveraged to create intuitive and relevant human-machine interfaces and generate a particular system behavior to provide active physical assistance and present relevant sensory information to the surgeon. These include basic manipulation assistance, audio-visual and haptic feedback, intraoperative imaging and force sensing. The resulting functionality, and the proposed architecture and design methods generalize to other microsurgical procedures. The system's performance is demonstrated and evaluated using phantoms and in vivo experiments

Cable-driven parallel robot for transoral laser phonosurgery

Transoral laser phonosurgery (TLP) is a common surgical procedure in otolaryngology. Currently, two techniques are commonly used: free beam and fibre delivery. For free beam delivery, in combination with laser scanning techniques, accurate laser pattern scanning can be achieved. However, a line-of-sight to the target is required. A suspension laryngoscope is adopted to create a straight working channel for the scanning laser beam, which could introduce lesions to the patient, and the manipulability and ergonomics are poor. For the fibre delivery approach, a flexible fibre is used to transmit the laser beam, and the distal tip of the laser fibre can be manipulated by a flexible robotic tool. The issues related to the limitation of the line-of-sight can be avoided. However, the laser scanning function is currently lost in this approach, and the performance is inferior to that of the laser scanning technique in the free beam approach. A novel cable-driven parallel robot (CDPR), LaryngoTORS, has been developed for TLP. By using a curved laryngeal blade, a straight suspension laryngoscope will not be necessary to use, which is expected to be less traumatic to the patient. Semi-autonomous free path scanning can be executed, and high precision and high repeatability of the free path can be achieved. The performance has been verified in various bench and ex vivo tests. The technical feasibility of the LaryngoTORS robot for TLP was considered and evaluated in this thesis. The LaryngoTORS robot has demonstrated the potential to offer an acceptable and feasible solution to be used in real-world clinical applications of TLP. Furthermore, the LaryngoTORS robot can combine with fibre-based optical biopsy techniques. Experiments of probe-based confocal laser endomicroscopy (pCLE) and hyperspectral fibre-optic sensing were performed. The LaryngoTORS robot demonstrates the potential to be utilised to apply the fibre-based optical biopsy of the larynx.Open Acces

Control and Estimation Methods Towards Safe Robot-assisted Eye Surgery

Vitreoretinal surgery is among the most delicate surgical tasks in which physiological hand tremor may severely diminish surgeon performance and put the eye at high risk of injury. Unerring targeting accuracy is required to perform precise operations on micro-scale tissues. Tool tip to tissue interaction forces are usually below human tactile perception, which may result in exertion of excessive forces to the retinal tissue leading to irreversible damages. Notable challenges during retinal surgery lend themselves to robotic assistance which has proven beneficial in providing a safe steady-hand manipulation. Efficient assistance from the robots heavily relies on accurate sensing and intelligent control algorithms of important surgery states and situations (e.g. instrument tip position measurements and control of interaction forces). This dissertation provides novel control and state estimation methods to improve safety during robot-assisted eye surgery. The integration of robotics into retinal microsurgery leads to a reduction in surgeon perception of tool-to-tissue forces at sclera. This blunting of human tactile sensory input, which is due to the inflexible inertia of the robot, is a potential iatrogenic risk during robotic eye surgery. To address this issue, a sensorized surgical instrument equipped with Fiber Bragg Grating (FBG) sensors, which is capable of measuring the sclera forces and instrument insertion depth into the eye, is integrated to the Steady-Hand Eye Robot (SHER). An adaptive control scheme is then customized and implemented on the robot that is intended to autonomously mitigate the risk of unsafe scleral forces and excessive insertion of the instrument. Various preliminary and multi-user clinician studies are then conducted to evaluate the effectiveness of the control method during mock retinal surgery procedures. In addition, due to inherent flexibility and the resulting deflection of eye surgical instruments as well as the need for targeting accuracy, we have developed a method to enhance deflected instrument tip position estimation. Using an iterative method and microscope data, we develop a calibration- and registration-independent (RI) framework to provide online estimates of the instrument stiffness (least squares and adaptive). The estimations are then combined with a state-space model for tip position evolution obtained based on the forward kinematics (FWK) of the robot and FBG sensor measurements. This is accomplished using a Kalman Filtering (KF) approach to improve the instrument tip position estimation during robotic surgery. The entire framework is independent of camera-to-robot coordinate frame registration and is evaluated during various phantom experiments to demonstrate its effectiveness

Force-Sensing-Based Multi-Platform Robotic Assistance for Vitreoretinal Surgery

Vitreoretinal surgery aims to treat disorders of the retina, vitreous body, and macula, such as retinal detachment, diabetic retinopathy, macular hole, epiretinal membrane and retinal vein occlusion. Challenged by several technical and human limitations, vitreoretinal practice currently ranks amongst the most demanding fields in ophthalmic surgery. Of vitreoretinal procedures, membrane peeling is the most common to be performed, over 0.5 million times annually, and among the most prone to complications. It requires an extremely delicate tissue manipulation by various micron scale maneuvers near the retina despite the physiological hand tremor of the operator. In addition, to avoid injuries, the applied forces on the retina need to be kept at a very fine level, which is often well below the tactile sensory threshold of the surgeon. Retinal vein cannulation is another demanding procedure where therapeutic agents are injected into occluded retinal veins. The feasibility of this treatment is limited due to challenges in identifying the moment of venous puncture, achieving cannulation and maintaining it throughout the drug delivery period. Recent advancements in medical robotics have significant potential to address most of the challenges in vitreoretinal practice, and therefore to prevent traumas, lessen complications, minimize intra-operative surgeon effort, maximize surgeon comfort, and promote patient safety. This dissertation presents the development of novel force-sensing tools that can easily be used on various robotic platforms, and robot control methods to produce integrated assistive surgical systems that work in partnership with surgeons against the current limitations in vitreoretinal surgery, specifically focusing on membrane peeling and vein cannulation procedures. Integrating high sensitivity force sensing into the ophthalmic instruments enables precise quantitative monitoring of applied forces. Auditory feedback based upon the measured forces can inform (and warn) the surgeon quickly during the surgery and help prevent injury due to excessive forces. Using these tools on a robotic platform can attenuate hand tremor of the surgeon, which effectively promotes tool manipulation accuracy. In addition, based upon certain force signatures, the robotic system can precisely identify critical instants, such as the venous puncture in retinal vein cannulation, and actively guide the tool towards clinical targets, compensate any involuntary motion of the surgeon, or generate additional motion that will make the surgical task easier. The experimental results using two distinct robotic platforms, the Steady-Hand Eye Robot and Micron, in combination with the force-sensing ophthalmic instruments, show significant performance improvement in artificial dry phantoms and ex vivo biological tissues

Vitreo-retinal eye surgery robot : sustainable precision

Vitreo-retinal eye surgery encompasses the surgical procedures performed on the vitreous humor and the retina. A procedure typically consists of the removal of the vitreous humor, the peeling of a membrane and/or the repair of a retinal detachment. Vitreo-retinal surgery is performed minimal invasively. Small needle shaped instruments are inserted into the eye. Instruments are manipulated by hand in four degrees of freedom about the insertion point. Two rotations move the instrument tip laterally, in addition to a translation in axial instrument direction and a rotation about its longitudinal axis. The manipulation of the instrument tip, e.g. a gripping motion can be considered as a fifth degree of freedom. While performing vitreo-retinal surgery manually, the surgeon faces various challenges. Typically, delicate micrometer range thick tissue is operated, for which steady hand movements and high accuracy instrument manipulation are required. Lateral instrument movements are inverted by the pivoting insertion point and scaled depending on the instrument insertion depth. A maximum of two instruments can be used simultaneously. There is nearly no perception of surgical forces, since most forces are below the human detection limit. Therefore, the surgeon relies only on visual feedback, obtained via a microscope or endoscope. Both vision systems force the surgeon to work in a static and non ergonomic body posture. Although the surgeon’s proficiency improves throughout his career, hand tremor will become a problem at higher age. Robotically assisted surgery with a master-slave system can assist the surgeon in these challenges. The slave system performs the actual surgery, by means of instrument manipulators which handle the instruments. The surgeon remains in control of the instruments by operating haptic interfaces via a master. Using electronic hardware and control software, the master and slave are connected. Amongst others, advantages as tremor filtering, up-scaled force feedback, down-scaled motions and stabilized instrument positioning will enhance dexterity on surgical tasks. Furthermore, providing the surgeon an ergonomic body posture will prolong the surgeon’s career. This thesis focuses on the design and realization of a high precision slave system for eye surgery. The master-slave system uses a table mounted design, where the system is compact, lightweight, easy to setup and equipped to perform a complete intervention. The slave system consists of two main parts: the instrument manipulators and their passive support system. Requirements are derived from manual eye surgery, conversations with medical specialists and analysis of the human anatomy and vitreo-retinal interventions. The passive support system provides a stiff connection between the instrument manipulator, patient and surgical table. Given the human anatomical diversity, presurgical adjustments can be made to allow the instrument manipulators to be positioned over each eye. Most of the support system is integrated within the patient’s headrest. On either the left or right side, two exchangeable manipulator-support arms can be installed onto the support system, depending on the eye being operated upon. The compact, lightweight and easy to install design, allows for a short setup time and quick removal in case of a complication. The slave system’s surgical reach is optimized to emulate manually performed surgery. For bimanual instrument operation, two instrument manipulators are used. Additional instrument manipulators can be used for non-active tools e.g. an illumination probe or an endoscope. An instrument manipulator allows the same degrees of freedom and a similar reach as manually performed surgery. Instrument forces are measured to supply force feedback to the surgeon via haptic interfaces. The instrument manipulator is designed for high stiffness, is play free and has low friction to allow tissue manipulation with high accuracy. Each instrument manipulator is equipped with an on board instrument change system, by which instruments can be changed in a fast and secure way. A compact design near the instrument allows easy access to the surgical area, leaving room for the microscope and peripheral equipment. The acceptance of a surgical robot for eye surgery mostly relies on equipment safety and reliability. The design of the slave system features various safety measures, e.g. a quick release mechanism for the instrument manipulator and additional locks on the pre-surgical adjustment fixation clamp. Additional safety measures are proposed, like a hard cover over the instrument manipulator and redundant control loops in the controlling FPGA. A method to fixate the patient’s head to the headrest by use of a custom shaped polymer mask is proposed. Two instrument manipulators and their passive support system have been realized so far, and the first experimental results confirm the designed low actuation torque and high precision performance