Telerobotic neurovascular interventions with magnetic manipulation.

Advances in robotic technology have been adopted in various subspecialties of both open and minimally invasive surgery, offering benefits such as enhanced surgical precision and accuracy with reduced fatigue of the surgeon. Despite the advantages, robotic applications to endovascular neurosurgery have remained largely unexplored because of technical challenges such as the miniaturization of robotic devices that can reach the complex and tortuous vasculature of the brain. Although some commercial systems enable robotic manipulation of conventional guidewires for coronary and peripheral vascular interventions, they remain unsuited for neurovascular applications because of the considerably smaller and more tortuous anatomy of cerebral arteries. Here, we present a teleoperated robotic neurointerventional platform based on magnetic manipulation. Our system consists of a magnetically controlled guidewire, a robot arm with an actuating magnet to steer the guidewire, a set of motorized linear drives to advance or retract the guidewire and a microcatheter, and a remote-control console to operate the system under real-time fluoroscopy. We demonstrate our system's capability to navigate narrow and winding pathways both in vitro with realistic neurovascular phantoms representing the human anatomy and in vivo in the porcine brachial artery with accentuated tortuosity for preclinical evaluation. We further demonstrate telerobotically assisted therapeutic procedures including coil embolization and clot retrieval thrombectomy for treating cerebral aneurysms and ischemic stroke, respectively. Our system could enable safer and quicker access to hard-to-reach lesions while minimizing the radiation exposure to physicians and open the possibility of remote procedural services to address challenges in current stroke systems of care.

Feasibility and accuracy of a robotic guidance system for navigated spine surgery in a hybrid operating room: a cadaver study.

The combination of navigation and robotics in spine surgery has the potential to accurately identify and maintain bone entry position and planned trajectory. The goal of this study was to examine the feasibility, accuracy and efficacy of a new robot-guided system for semi-automated, minimally invasive, pedicle screw placement. A custom robotic arm was integrated into a hybrid operating room (OR) equipped with an augmented reality surgical navigation system (ARSN). The robot was mounted on the OR-table and used to assist in placing Jamshidi needles in 113 pedicles in four cadavers. The ARSN system was used for planning screw paths and directing the robot. The robot arm autonomously aligned with the planned screw trajectory, and the surgeon inserted the Jamshidi needle into the pedicle. Accuracy measurements were performed on verification cone beam computed tomographies with the planned paths superimposed. To provide a clinical grading according to the Gertzbein scale, pedicle screw diameters were simulated on the placed Jamshidi needles. A technical accuracy at bone entry point of 0.48 ± 0.44 mm and 0.68 ± 0.58 mm was achieved in the axial and sagittal views, respectively. The corresponding angular errors were 0.94 ± 0.83° and 0.87 ± 0.82°. The accuracy was statistically superior (p < 0.001) to ARSN without robotic assistance. Simulated pedicle screw grading resulted in a clinical accuracy of 100%. This study demonstrates that the use of a semi-automated surgical robot for pedicle screw placement provides an accuracy well above what is clinically acceptable.

Design and control of an image-guided robot for spine surgery in a hybrid OR.

BACKGROUND: Minimally invasive spine (MIS) fusion surgery requires image guidance and expert manual dexterity for a successful, efficient, and accurate pedicle screw placement. Operating room (OR)-integrated robotic solution can provide precise assistance to potentially minimize complication rates and facilitate difficult MIS procedures. METHODS: A 5-degrees of freedom robot was designed specifically for a hybrid OR with integrated surgical navigation for guiding pedicle screw pilot holes. The system automatically aligns an instrument following the surgical plan using only instrument tracking feedback. Contrary to commercially available robotic systems, no tracking markers on the robotic arm are required. The system was evaluated in a cadaver study. RESULTS: The mean targeting error (N = 34) was 1.27±0.57 mm and 1.62±0.85°, with 100% of insertions graded as clinically acceptable. CONCLUSIONS: A fully integrated robotic guidance system, including intra-op imaging, planning, and physical guidance with optimized robot design and control, can improve workflow and provide pedicle screw guidance with less than 2 mm targeting error.

Robotic microlaryngeal phonosurgery: Testing of a "steady-hand" microsurgery platform.

OBJECTIVES/HYPOTHESIS: To evaluate gains in microlaryngeal precision achieved by using a novel robotic "steady hand" microsurgery platform in performing simulated phonosurgical tasks. STUDY DESIGN: Crossover comparative study of surgical performance and descriptive analysis of surgeon feedback. METHODS: A novel robotic ear, nose, and throat microsurgery system (REMS) was tested in simulated phonosurgery. Participants navigated a 0.4-mm-wide microlaryngeal needle through spirals of varying widths, both with and without robotic assistance. Fail time (time the needle contacted spiral edges) was measured, and statistical comparison was performed. Participants were surveyed to provide subjective feedback on the REMS. RESULTS: Nine participants performed the task at three spiral widths, yielding 27 paired testing conditions. In 24 of 27 conditions, robot-assisted performance was better than unassisted; five trials were errorless, all achieved with the robot. Paired analysis of all conditions revealed fail time of 0.769 ± 0.568 seconds manually, improving to 0.284 ± 0.584 seconds with the robot (P = .003). Analysis of individual spiral sizes showed statistically better performance with the REMS at spiral widths of 2 mm (0.156 ± 0.226 seconds vs. 0.549 ± 0.545 seconds, P = .019) and 1.5 mm (0.075 ± 0.099 seconds vs. 0.890 ± 0.518 seconds, P = .002). At 1.2 mm, all nine participants together showed similar performance with and without robotic assistance (0.621 ± 0.923 seconds vs. 0.868 ± 0.634 seconds, P = .52), though subgroup analysis of five surgeons most familiar with microlaryngoscopy showed statistically better performance with the robot (0.204 ± 0.164 seconds vs. 0.664 ± 0.354 seconds, P = .036). CONCLUSIONS: The REMS is a novel platform with potential applications in microlaryngeal phonosurgery. Further feasibility studies and preclinical testing should be pursued as a bridge to eventual clinical use. LEVEL OF EVIDENCE: NA. Laryngoscope, 128:126-132, 2018.

The robotic ENT microsurgery system: A novel robotic platform for microvascular surgery.

OBJECTIVE: Assess the feasibility of a novel robotic platform for use in microvascular surgery. STUDY DESIGN: Prospective feasibility study. SETTING: Robotics laboratory. METHODS: The Robotic ENT (Ear, Nose, and Throat) Microsurgery System (REMS) (Galen Robotics, Inc., Sunnyvale, CA) is a robotic arm that stabilizes a surgeon's instrument, allowing precise, tremor-free movement. Six microvascular naïve medical students and one microvascular expert performed microvascular anastomosis of a chicken ischiatic artery, with and without the REMS. Trials were blindly graded by seven microvascular surgeons using a microvascular tremor scale (MTS) based on instrument tip movement as a function of vessel width. Time to completion (TTC) was measured, and an exit survey assessed participants' experience. The interrater reliability of the MTS was calculated. RESULTS: For microvascular-naïve participants, the mean MTS score for REMS-assisted trials was 0.72 (95% confidence interval [CI] 0.64-1.07) and 2.40 (95% CI 2.12-2.69) for freehand (P < 0.001). The mean TTC was 1,265 seconds for REMS-assisted trials and 1,320 seconds for freehand (P > 0.05). For the microvascular expert, the mean REMS-assisted MTS score was 0.71 (95% CI 0.15-1.27) and 0.86 (95% CI 0.35-1.37) for freehand (P > 0.05). TTC was 353 seconds for the REMS-assisted trial and 299 seconds for freehand. All participants thought the REMS was more accurate and improved instrument handling and stability. The intraclass correlation coefficient for MTS ratings was 0.914 (95% CI 0.823-0.968) for consistency and 0.901 (95% CI 0.795-0.963) for absolute value. CONCLUSION: The REMS is a feasible adjunct for microvascular surgery and a potential teaching tool capable of reducing tremor in novice users. Furthermore, the MTS is a feasible grading system for assessing microvascular tremor. LEVEL OF EVIDENCE: NA. Laryngoscope, 127:2495-2500, 2017.

Accuracy assessment and kinematic calibration of the robotic endoscopic microsurgical system.

This paper explores the general stereotactic accuracy of the Robotic Endoscopic Microsurgical System (REMS) by calibrating with a standard optical tracking system. Based on a simple yet effective test protocol, the proposed calibration method combines hand-eye calibration with Bernstein polynomials to improve our kinematic pose accuracy.

A Multi-Function Force Sensing Instrument for Variable Admittance Robot Control in Retinal Microsurgery.

Robotic systems have the potential to assist vitreoretinal surgeons in extremely difficult surgical tasks inside the human eye. In addition to reducing hand tremor and improving tool positioning, a robotic assistant can provide assistive motion guidance using virtual fixtures, and incorporate real-time feedback from intraocular force sensing ophthalmic instruments to present tissue manipulation forces, that are otherwise physically imperceptible to the surgeon. This paper presents the design of an FBG-based, multi-function instrument that is capable of measuring mN-level forces at the instrument tip located inside the eye, and also the sclera contact location on the instrument shaft and the corresponding contact force. The given information is used to augment cooperatively controlled robot behavior with variable admittance control. This effectively creates an adaptive remote center-of-motion (RCM) constraint to minimize eye motion, but also allows the translation of the RCM location if the instrument is not near the retina. In addition, it provides force scaling for sclera force feedback. The calibration and validation of the multi-function force sensing instrument are presented, along with demonstration and performance assessment of the variable admittance robot control on an eye phantom.

Human eye phantom for developing computer and robot-assisted epiretinal membrane peeling.

A number of technologies are being developed to facilitate key intraoperative actions in vitreoretinal microsurgery. There is a need for cost-effective, reusable benchtop eye phantoms to enable frequent evaluation of these developments. In this study, we describe an artificial eye phantom for developing intraocular imaging and force-sensing tools. We test four candidate materials for simulating epiretinal membranes using a handheld tremor-canceling micromanipulator with force-sensing micro-forceps tip and demonstrate peeling forces comparable to those encountered in clinical practice.

Improvement of optical coherence tomography using active handheld micromanipulator in vitreoretinal surgery.

An active handheld micromanipulator has been developed to cancel hand tremor during microsurgery. The micromanipulator is also applicable in optical coherence tomography to improve the quality of scanning and minimize surgical risks during the scans. The manipulator can maneuver the tool tip with six degrees of freedom within a cylindrical workspace 4 mm in diameter and 4 mm high. The imaging system is equipped with a 25-gauge Fourier-domain common-path OCT probe. This paper introduces the handheld OCT imaging system and techniques involved and presents stabilized OCT images of A-mode and M-mode scans in air and live rabbit eyes. We show the first demonstration of OCT imaging using the active handheld micromanipulator in vivo.

Auditory force feedback substitution improves surgical precision during simulated ophthalmic surgery.

PURPOSE: To determine the extent that auditory force feedback (AFF) substitution improves performance during a simulated ophthalmic peeling procedure. METHODS: A 25-gauge force-sensing microforceps was linked to two AFF modes. The "alarm" AFF mode sounded when the force reached 9 mN. The "warning" AFF mode made beeps with a frequency proportional to the generated force. Participants with different surgical experience levels were asked to peel a series of bandage strips off a platform as quickly as possible without exceeding 9 mN of force. In study arm A, participants peeled with alarm and warning AFF modes, the order randomized within the experience level. In study arm B, participants first peeled without AFF, then alarm or warning AFF (order randomized within the experience level), and finally without AFF. RESULTS: Of the 28 "surgeon" participants, AFF improved membrane peeling performance, reducing average force generated (P < 0.01), SD of forces (P < 0.05), and force × time above 9 mN (P < 0.01). Short training periods with AFF improved subsequent peeling performance when AFF was turned off, with reductions in average force, SD of force, maximum force, time spent above 9 mN, and force × time above 9 mN (all P < 0.001). Except for maximum force, peeling with AFF reduced all force parameters (P < 0.05) more than peeling without AFF after completing a training session. CONCLUSIONS: AFF enables the surgeon to reduce the forces generated with improved precision during phantom membrane peeling, regardless of surgical experience. New force-sensing surgical tools combined with AFF offer the potential to enhance surgical training and improve surgical performance.

A force-sensing microsurgical instrument that detects forces below human tactile sensation.

PURPOSE: To test the sensitivity and reproducibility of a 25-gauge force-sensing micropick during microsurgical maneuvers that are below tactile sensation. METHODS: Forces were measured during membrane peeling in a "raw egg" and the chick chorioallantoic membrane models (N = 12) of epiretinal membranes. Forces were also measured during posterior hyaloid detachment and creation of retinal tears during vitrectomy in live rabbits (n = 6). RESULTS: With the raw egg model, 0.5 ± 0.4 mN of force was detected during membrane peeling. In the chorioallantoic membrane model, delaminating the upper membrane produced 2.8 ± 0.2 mN of force. While intentionally rupturing the lower membrane to simulate a retinal tear, 7.3 ± 0.5 mN (range, 5.1-9.2 mN; P < 0.001) of force was generated while peeling the upper membrane. During vitrectomy, the minimum force that detached the posterior hyaloid was 6.7 ± 1.1 mN, which was similar to the force of 6.4 ± 1.4 mN that caused a retinal tear. The rate of force generation, as indicated by the first derivative of force generation, was 3.4 ± 1.2 mN/second during posterior hyaloid detachment, compared with 7.7 ± 2.4 mN/second during the creation of a retinal tear (P = 0.04). CONCLUSION: Force-sensing microsurgical instruments can detect forces below tactile sensation, and importantly, they can distinguish the forces generated during normal maneuvers from those that cause a surgical complication.

A Novel Dual Force Sensing Instrument with Cooperative Robotic Assistant for Vitreoretinal Surgery.

Robotic assistants and smart surgical instruments have been developed to overcome many significant physiological limitations faced by vitreoretinal surgeons, one of which is lack of force perception below 7.5 mN. This paper reports the development of a new force sensor based on fiber Bragg grating (FBG) with the ability to sense forces at the tip of the surgical instrument located inside the eye and also provide information about instrument interaction with the sclera. The sclera section provides vital feedback for cooperative robot control to minimize potentially dangerous forces on the eye. Preliminary results with 2×2 degree-of-freedom (DOF) sensor and force scaling robot control demonstrate significant reduction of forces on the sclera. The design and analysis of the sensor is presented along with a simulated robot assisted retinal membrane peeling on a phantom with sclera constraints and audio feedback.

Evaluation of a Micro-Force Sensing Handheld Robot for Vitreoretinal Surgery.

Highly accurate positioning is fundamental to the performance of vitreoretinal microsurgery. Of vitreoretinal procedures, membrane peeling is among the most prone to complications since extremely delicate manipulation of retinal tissue is required. Associated tool-to-tissue interaction forces are usually below the threshold of human perception, and the surgical tools are moved very slowly, within the 0.1-0.5 mm/s range. During the procedure, unintentional tool motion and excessive forces can easily give rise to vision loss or irreversible damage to the retina. A successful surgery includes two key features: controlled tremor-free tool motion and control of applied force. In this study, we present the potential benefits of a micro-force sensing robot in vitreoretinal surgery. Our main contribution is implementing fiber Bragg grating based force sensing in an active tremor canceling handheld micromanipulator, known as Micron, to measure tool-to-tissue interaction forces in real time. Implemented auditory sensory substitution assists in reducing and limiting forces. In order to test the functionality and performance, the force sensing Micron was evaluated in peeling experiments with adhesive bandages and with the inner shell membrane from chicken eggs. Our findings show that the combination of active tremor canceling together with auditory sensory substitution is the most promising aid that keeps peeling forces below 7 mN with a significant reduction in 2-20 Hz oscillations.

Optical coherence tomography scanning with a handheld vitreoretinal micromanipulator.

An active handheld micromanipulator has been developed that is capable of automated intraocular acquisition of B-mode and C-mode optical coherence tomography scans that are up to 4 mm wide. The manipulator is a handheld Gough-Stewart platform actuated by ultrasonic linear motors. The manipulator has been equipped with a Fourier-domain common-path intraocular OCT probe that fits within a 25-gauge needle. The paper describes the systems and techniques involved, and presents preliminary results of B-mode and C-mode scans.

Force sensing micro-forceps for robot assisted retinal surgery.

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.

Hybrid tracking and mosaicking for information augmentation in retinal surgery.

Current technical limitations in retinal surgery hinder the ability of surgeons to identify and localize surgical targets, increasing operating times and risks of surgical error. In this paper we present a hybrid tracking and mosaicking method for augmented reality in retinal surgery. The system is a combination of direct and feature-based tracking methods. A novel extension for direct visual tracking using a robust image similarity measure in color images is also proposed. Several experiments conducted on phantom, in vivo rabbit and human images attest the ability of the method to cope with the challenging retinal surgery scenario. Applications of the proposed method for tele-mentoring and intra-operative guidance are demonstrated.

Component-based software for dynamic configuration and control of computer assisted intervention systems: Release 1.0.

This paper presents the rationale for the use of a component-based architecture for computer-assisted intervention (CAI) systems, including the ability to reuse components and to easily develop distributed systems. We introduce three additional capabilities, however, that we believe are especially important for research and development of CAI systems. The first is the ability to deploy components among different processes (as conventionally done) or within the same process (for optimal real-time performance), without requiring source-level modifications to the component. This is particularly relevant for real-time video processing, where the use of multiple processes could cause perceptible delays in the video stream. The second key feature is the ability to dynamically reconfigure the system. In a system composed of multiple processes on multiple computers, this allows one process to be restarted (e.g., after correcting a problem) and reconnected to the rest of the system, which is more convenient than restarting the entire distributed application and enables better fault recovery. The third key feature is the availability of run-time tools for data collection, interactive control, and introspection, and offline tools for data analysis and playback. The above features are provided by the open-source cisst software package, which forms the basis for the Surgical Assistant Workstation (SAW) framework. A complex computer-assisted intervention system for retinal microsurgery is presented as an example that relies on these features. This system integrates robotics, stereo microscopy, force sensing, and optical coherence tomography (OCT) imaging to transcend the current limitations of vitreoretinal surgery.

Automatic online spectral calibration of Fourier-domain OCT for robotic surgery.

We present a new automatic spectral calibration (ASC) method for spectral Domain optical coherence tomography (SD-OCT). Our ASC method calibrates the spectral mapping of the spectrometer in SD-OCT, and does not require external calibrating light source or a commercial spectral analyzer. The ASC method simultaneously calibrates the physical pixel spacing of the A-scan in static and dynamic environments. Experimental results show that the proposed ASC method can provide satisfactory calibration for SD-OCT to achieve high axial resolution and high ranging accuracy, without increasing hardware complexity.

Prototyping a Hybrid Cooperative and Tele-robotic Surgical System for Retinal Microsurgery.

This paper presents the design of a tele-robotic microsurgical platform designed for development of cooperative and tele-operative control schemes, sensor based smart instruments, user interfaces and new surgical techniques with eye surgery as the driving application. The system is built using the distributed component-based cisst libraries and the Surgical Assistant Workstation framework. It includes a cooperatively controlled EyeRobot2, a da Vinci Master manipulator, and a remote stereo visualization system. We use constrained optimization based virtual fixture control to provide Virtual Remote-Center-of-Motion (vRCM) and haptic feedback. Such system can be used in a hybrid setup, combining local cooperative control with remote tele-operation, where an experienced surgeon can provide hand-over-hand tutoring to a novice user. In another scheme, the system can provide haptic feedback based on virtual fixtures constructed from real-time force and proximity sensor information.

Towards automatic calibration of Fourier-Domain OCT for robot-assisted vitreoretinal surgery.

We present a new real-time automatic spectral calibration (ASC) method for Fourier domain optical coherence tomography (FD OCT) that can be automatically performed by the system. The ASC method proposed can be performed during OCT scanning operation and does not require an external calibrating light source or a commercial optical spectrum analyzer. Spectral data used for calibration can be interferograms obtained from an arbitrary sample which may have complicated internal structures, such as ones found in biological tissue. Moreover, our ASC method incorporates known robot motion to calibrate physical pixel spacing of the A-scan in static or dynamic environments. Experimental results show that our ASC method can provide high-performance calibration for FD OCT in terms of axial resolution and ranging accuracy without increasing hardware complexity.