Toward certifiable optimal motion planning for medical steerable needles

Medical steerable needles can follow 3D curvilinear trajectories to avoid anatomical obstacles and reach clinically significant targets inside the human body. Automating steerable needle procedures can enable physicians and patients to harness the full potential of steerable needles by maximally leveraging their steerability to safely and accurately reach targets for medical procedures such as biopsies. For the automation of medical procedures to be clinically accepted, it is critical from a patient care, safety, and regulatory perspective to certify the correctness and effectiveness of the planning algorithms involved in procedure automation. In this paper, we take an important step toward creating a certifiable optimal planner for steerable needles. We present an efficient, resolution-complete motion planner for steerable needles based on a novel adaptation of multi-resolution planning. This is the first motion planner for steerable needles that guarantees to compute in finite time an obstacle-avoiding plan (or notify the user that no such plan exists), under clinically appropriate assumptions. Based on this planner, we then develop the first resolution-optimal motion planner for steerable needles that further provides theoretical guarantees on the quality of the computed motion plan, that is, global optimality, in finite time. Compared to state-of-the-art steerable needle motion planners, we demonstrate with clinically realistic simulations that our planners not only provide theoretical guarantees but also have higher success rates, have lower computation times, and result in higher quality plans.

Flexible Pressure Sensors Based on Microcrack Structure and Composite Conductive Mechanism for Medical Robotic Applications

With the advancement of intelligent medical robot technology, machine touch utilizing flexible sensors has emerged as a prominent research area. In this study, a flexible resistive pressure sensor was designed incorporating a microcrack structure with air pores and a composite conductive mechanism of silver/carbon. The aim was to achieve enhanced stability and sensitivity with the inclusion of macro through-holes (1-3 mm) to expand the sensitive range. This technology solution was specifically applied to the machine touch system of the B-ultrasound robot. Through meticulous experimentation, it was determined that the optimal approach involved uniformly blending ecoflex and nano carbon powder at a mass ratio of 5:1, and subsequently combining the mixture with an ethanol solution of silver nanowires (AgNWs) at a mass ratio of 6:1. This combination of components resulted in the fabrication of a pressure sensor with optimal performance. Under the pressure testing condition of 5 kPa, a comparison of the resistance change rate was conducted among samples using the optimal formulation from the three processes. It was evident that the sample of ecoflex-C-AgNWs/ethanol solution exhibited the highest sensitivity. Its sensitivity was increased by 19.5% compared to the sample (ecoflex-C) and by 11.3% compared to the sample (ecoflex-C-ethanol). The sample (ecoflex-C-AgNWs/ethanol solution), which only incorporated internal air pore microcracks without through-holes, exhibited sensitive response to pressures below 5 N. However, with the addition of through-holes, the measurement range of its sensitive response increased to 20 N, representing a 400% increase in the measurement range.

[Feasibility analysis of puncture robot technology for the application of acupuncture robot]

The difficulties such as how to accurately locate acupoints and safely insert needles are presented in acupuncture robot. The puncture robot with high technological similarity to acupuncture robot is getting mature, and a large number of human trials and animal experiments have been conducted for the development of puncture robot. Through comparing the similarities and differences between puncture robot and acupuncture robot in the aspects of through-skin puncture, needle insertion and needle removal, the valuable technology of puncture robot is analyzed for the development of acupuncture robot, and the crucial direction of technology migration is determined. ①Integrating the mechanical feedback and medical imaging technology and utilizing the multi-modal perception to achieve the safety of acupuncture operation. ②Emphasizing the integration of the existing designs of chest puncture robot to realize the acupuncture operation with inhalation and exhalation involved. ③Focusing on the development of relevant technology of automatic needle removal through conducting the actual scenario of treatment with acupuncture robot in patients under non-anaesthetic condition.

Path Planning for Obstacle Avoidance of Robot Arm Based on Improved Potential Field Method

In medical and surgical scenarios, the trajectory planning of a collaborative robot arm is a difficult problem. The artificial potential field (APF) algorithm is a classic method for robot trajectory planning, which has the characteristics of good real-time performance and low computing consumption. There are many variants of the APF algorithm, among which the most widely used variants is the velocity potential field (VPF) algorithm. However, the traditional VPF algorithm has inherent defects and problems, such as easily falling into local minimum, being unable to reach the target, poor dynamic obstacle avoidance ability, and safety and efficiency problems. Therefore, this work presents the improved velocity potential field (IVPF) algorithm, which considers direction factors, obstacle velocity factor, and tangential velocity. When encountering dynamic obstacles, the IVPF algorithm can avoid obstacles better to ensure the safety of both the human and robot arm. The IVPF algorithm also does not easily fall into a local problem when encountering different obstacles. The experiments informed the RRT* algorithm, VPF algorithm, and IVPF algorithm for comparison. Compared with the informed RRT* and VPF algorithm, the result of experiments indicate that the performances of the IVPF algorithm have significant improvements when dealing with different obstacles. The main aim of this paper is to provide a safe and efficient path planning algorithm for the robot arm in the medical field. The proposed algorithm can ensure the safety of both the human and the robot arm when the medical and surgical robot arm is working, and enables the robot arm to cope with emergencies and perform tasks better. The application of the proposed algorithm could make the collaborative robots work in a flexible and safe condition, which could open up new opportunities for the future development of medical and surgical scenarios.

CochleRob: Parallel-Serial Robot to Position a Magnetic Actuator around a Patient's Head for Intracochlear Microrobot Navigation

Our work introduces a new robotic solution named CochleRob, which is used for the administration of super-paramagnetic antiparticles as drug carriers into the human cochlea for the treatment of hearing loss caused by damaged cochlea. This novel robot architecture presents two key contributions. First, CochleRob has been designed to meet specifications pertaining to ear anatomy, including workspace, degrees of freedom, compactness, rigidity, and accuracy. The first objective was to develop a safer mathod to administer drugs to the cochlea without the need for catheter or CI insertion. Secondly, we aimed at developing and validating the mathemathical models, including forward, inverse, and dynamic models, to support the robot function. Our work provides a promising solution for drug administration into the inner ear.

Suppression of Clothing-Induced Acoustic Attenuation in Robotic Auscultation

For patients who are often embarrassed and uncomfortable when exposing their breasts and having them touched by physicians of different genders during auscultation, we are developing a robotic system that performs auscultation over clothing. As the technical issue, the sound obtained through the clothing is often attenuated. This study aims to investigate clothing-induced acoustic attenuation and develop a suppression method for it. Because the attenuation is due to the loss of energy as sound propagates through a medium with viscosity, we hypothesized that the attenuation is improved by compressing clothing and shortening the sound propagation distance. Then, the amplitude spectrum of the heart sound was obtained over clothes of different thicknesses and materials in a phantom study and human trial at varying contact forces with a developed passive-actuated end-effector. Our results demonstrate the feasibility of the attenuation suppression method by applying an optimum contact force, which varied according to the clothing condition. In the phantom experiments, the attenuation rate was improved maximumly by 48% when applying the optimal contact force (1 N). In human trials, the attenuation rate was under the acceptable attenuation (40%) when applying the optimal contact force in all combinations in each subject. The proposed method promises the potential of robotic auscultation toward eliminating gender bias.

Towards fully automated robotic platform for remote auscultation

BACKGROUND

Since most developed countries are facing an increase in the number of patients per healthcare worker due to a declining birth rate and an ageing population, relatively simple and safe diagnosis tasks may need to be performed using robotics and automation technologies, without specialists and hospitals. This study presents an automated robotic platform for remote auscultation, which is a highly cost-effective screening tool for detecting abnormal clinical signs.

METHOD

The developed robotic platform is composed of a 6-degree-of-freedom cooperative robotic arm, LiDAR camera, and a spring-based mechanism holding an electric stethoscope. The platform enables autonomous stethoscope positioning based on external body information acquired using the LiDAR camera-based multi-way registration; the platform also ensures safe and flexible contact, maintaining the contact force within a certain range through the passive-actuated mechanism.

RESULTS

Our preliminary results confirm that the robotic platform enables estimation of the landing positions required for cardiac examinations based on the depth and landmark information of the body surface. It also handles the stethoscope while maintaining the contact force without relying on the push-in displacement by the robotic arm.

CONCLUSION

The developed robotic platform enables the estimation of the landing positions and handling the stethoscope while maintaining the contact force, which promises the potential of automatic remote auscultation.

Visual servoing of continuum robots: Methods, challenges, and prospects

BACKGROUND

Recent advancements in continuum robotics have accentuated developing efficient and stable controllers to handle shape deformation and compliance. The control of continuum robots (CRs) using physical sensors attached to the robot, particularly in confined spaces, is difficult due to their limited accuracy in three-dimensional deflections and challenging localisation. Therefore, using non-contact imaging sensors finds noticeable importance, particularly in medical scenarios. Accordingly, given the need for direct control of the robot tip and notable uncertainties in the kinematics and dynamics of CRs, many papers have focussed on the visual servoing (VS) of CRs in recent years.

METHODS

The significance of this research towards safe human-robot interaction has fuelled our survey on the previous methods, current challenges, and future opportunities.

RESULTS

Beginning with actuation modalities and modelling approaches, the paper investigates VS methods in medical and non-medical scenarios.

CONCLUSIONS

Finally, challenges and prospects of VS for CRs are discussed, followed by concluding remarks.

Contact Compliance Based Visual Feedback for Tool Alignment in Robot Assisted Bone Drilling

In recent decades, robot-assisted surgery has been proven superior at providing more accurate outcomes than the conventional one, particularly in minimally invasive procedures. However, there are still limitations to these kinds of surgical robots. Accurate bone drilling on the steep and hard surface of cortical bone is still challenging. The issues of slipping away from the target entry point on the bone surface and subsequently deviating from the desired path are still not completely solved. Therefore, in this paper, a force control is proposed to accompany the resolved motion rate controller in a handheld orthopedic robot system. The force control makes it possible to adjust the contact compliance of the drill to the bone surface. With the proper contact compliance, the drill can be prevented from deflecting in contact with the bone surface, and will eventually be directed to the target entry point. The experiments on test jig and vertebra phantom also show that the robot under the proposed contact compliance visual feedback control structure could produce better usability positioning accuracy under various contact disturbances than its counterpart.

[Research and development of intelligent medical equipment and internationalization of acupuncture and moxibustion: thoughts from researchers of acupuncture robot]

Under the background of artificial intelligence, the internationalization of acupuncture and moxibustion has braced an important opportunity. Intelligent medical equipment for acupuncture and moxibustion has entered from the laboratory into the clinic. However, the current research focuses on optimizing acupuncture treatment technology rather than innovating acupuncture theory. Internationally, the westernization of traditional acupuncture and the dilution of its characteristics are worrying. It is urgent to promote the China-led international standards of acupuncture and moxibustion and the patent protection of traditional acupuncture and moxibustion. Intelligent medical equipment will play the role of media, and promote the internationalization of traditional acupuncture and moxibustion with standardized and highly-integrated intelligent medical equipment for acupuncture and moxibustion, and integrate modern scientific and technological achievements. It is a feasible way for the internationalization of acupuncture and moxibustion.

A Human Gesture Mapping Method to Control a Multi-Functional Hand for Robot-Assisted Laparoscopic Surgery: The MUSHA Case

This work presents a novel technique to control multi-functional hand for robot-assisted laparoscopic surgery. We tested the technique using the MUSHA multi-functional hand, a robot-aided minimally invasive surgery tool with more degrees of freedom than the standard commercial end-effector of the da Vinci robot. Extra degrees of freedom require the development of a proper control strategy to guarantee high performance and avoid an increasing complexity of control consoles. However, developing reliable control algorithms while reducing the control side’s mechanical complexity is still an open challenge. In the proposed solution, we present a control strategy that projects the human hand motions into the robot actuation space. The human hand motions are tracked by a LeapMotion camera and mapped into the actuation space of the virtualized end-effector. The effectiveness of the proposed method was evaluated in a twofold manner. Firstly, we verified the Lyapunov stability of the algorithm, then an user study with 10 subjects assessed the intuitiveness and usability of the system.

Development of a Novel Anesthesia Airway Management Robot

Non-invasive positive pressure ventilation has attracted increasing attention for air management in general anesthesia. This work proposes a novel robot equipped with two snake arms and a mask-fastening mechanism to facilitate trachea airway management for anesthesia as well as deep sedation and to improve surgical outcomes. The two snake arms with supporting terminals have been designed to lift a patient's jaw with design optimization, and the mask-fastening mechanism has been utilized to fasten the mask onto a patient's face. The control unit has been developed to implement lifting and fastening force control with safety and robustness. Loading experiments on the snake arm and tension experiments on the mask-fastening mechanism have been performed to investigate and validate the performances of the proposed anesthesia airway management robot. Experiments on a mock person have also been employed to further verify the effectiveness and reliability of the developed robot system. As an early study of an anesthesia airway management robot, it was verified as a valid attempt to perform mask non-invasive positive pressure ventilation technology by taking advantage of a robotic system.

A Vascular Intervention Assist Device Using Bi-Motional Roller Cartridge Structure and Clinical Evaluation

Conventional vascular intervention procedures present issues including X-ray exposure during operation, and an experience-dependent success rate and clinical outcome. This paper presents a novel robotic system using modularized bi-motional roller cartridge assemblies for robotic vascular interventions, specifically percutaneous coronary interventions (PCIs). The patient-side robot manipulates instruments such as the guiding catheter, guidewire, balloon/stent catheter, and diagnostic sensor catheter via commands from the user interface device, which is controlled by the physician. The proposed roller cartridge assembly can accommodate instruments of various sizes with an active clamping mechanism, and implements simultaneous translation and rotation motions. It also implements force feedback in the physician-side system, to effectively monitor the patient-side system’s status. The positioning accuracy and precision in using the robotic system showed satisfactory performance in a phantom-based test. It was also confirmed, through animal experiments and a pilot clinical trial, that the system demonstrates feasibility for clinical use.

Improved Integrated Robotic Intraocular Snake

Retinal surgery can be performed only by surgeons possessing advanced surgical skills because of the small, confined intraocular space, and the restricted free motion of instruments in contact with the sclera. Snake-like robots could be essential for use in retinal surgery to overcome this problem. Such robots can approach from suitable directions and operate delicate tissues when performing retinal vein cannulation, epiretinal membrane peeling and so on. In this study, we propose an improved integrated robotic intraocular snake (I²RIS), which is a new version of our previous IRIS. This update focuses on the dexterous distal unit design and the drive unit design. The proposed dexterous distal unit consists of small elements with reduced contact stress. The proposed drive unit includes a new wire drive mechanism where the drive pulley is mounted at a right angle relative to the actuation direction (also, relative to the conventional direction). A geometric analysis and mechanical design show that the proposed drive mechanism is simpler and easier to assemble and yields higher accuracy than the conventional drive mechanism. Furthermore, considering clinical use, the instrument of the I²RIS is detachable from the motor unit for cleaning, sterilization, and attachment of various surgical tools. Weighing merely 31.3 g, the proposed mechanism is only one third of the weight of the conventional IRIS. The basic functions and effectiveness of the proposed mechanism are verified by experiments on 5:1 scaled-up models of the dexterous distal unit and actual-size models of the instrument and motor units.

Sensor-Embedded Automatic Grasping Forceps for Precise Corneal Suture in Penetrating Keratoplasty

In penetrating keratoplasty (PKP), the proper corneal suture placement is very important for successful transplantation and restoring functional vision. Generating sutures with accurate depth is difficult for the surgeon because of the tissue’s softness, lack of depth information, and hand tremors. In this paper, an automatic cornea grasping device is proposed, which detects when the device reaches the target suture depth. When the device reaches the target depth, the device rapidly grasps the cornea to prevent error induced by human hand tremors. In the paper, the performance of the proposed sensor, the actuator, and the device are experimentally verified with ex vivo experiment. The result showed that the proposed device could enhance the accuracy and precision of the corneal suture depth.

Autonomous Robot for Removing Superficial Traumatic Blood

Objective: To remove blood from an incision and find the incision spot is a key task during surgery, or else over discharge of blood will endanger a patient's life. However, the repetitive manual blood removal involves plenty of workload contributing fatigue of surgeons. Thus, it is valuable to design a robotic system which can automatically remove blood on the incision surface. Methods: In this paper, we design a robotic system to fulfill the surgical task of the blood removal. The system consists of a pair of dual cameras, a 6-DoF robotic arm, an aspirator whose handle is fixed to a robotic arm, and a pump connected to the aspirator. Further, a path-planning algorithm is designed to generate a path, which the aspirator tip should follow to remove blood. Results: In a group of simulating bleeding experiments on ex vivo porcine tissue, the contour of the blood region is detected, and the reconstructed spatial coordinates of the detected blood contour is obtained afterward. The BRR robot cleans thoroughly the blood running out the incision. Conclusions: This study contributes the first result on designing an autonomous blood removal medical robot. The skill of the surgical blood removal operation, which is manually operated by surgeons nowadays, is alternatively grasped by the proposed BRR medical robot.

A novel fluoroscopy-based robot system for pedicle screw fixation surgery

BACKGROUND

Robot-assisted pedicle screw insertion has gained popularity in the spinal surgery field. Due to high cost, these spinal robots are not extensively applied in clinical surgeries. Developing an effective robot system with low cost and high clinical acceptability is one of the future trends.

METHODS

We developed a novel fluoroscopy-based robot system for pedicle screw insertion. Four live pigs were conducted with percutaneous pedicle screw insertion. Robot-assisted surgery was performed on the left side of pedicle, while the right opposite side is placed by freehand. The respect accuracy, surgical time and fluoroscopy time were recorded.

RESULTS

Robot-assisted group achieved 100% (23/23) accuracy. The average times (6.4 ± 1.7) for intraoperative fluoroscopy usage per procedure were lesser than freehand group (12.5 ± 3.6), and the surgical time (6.8 ± 2.1 min) per screw was reduced compared with freehand group (12.1 ± 4.8 min).

CONCLUSIONS

Our robot system is cost-effective and feasible for pedicle screw placement. Low economic cost makes it easier for extensive application in primary hospitals.

Magnetic resonance and ultrasound image-guided navigation system using a needle manipulator

PURPOSE

Image guidance is crucial for percutaneous tumor ablations, enabling accurate needle-like applicator placement into target tumors while avoiding tissues that are sensitive to injury and/or correcting needle deflection. Although ultrasound (US) is widely used for image guidance, magnetic resonance (MR) is preferable due to its superior soft tissue contrast. The objective of this study was to develop and evaluate an MR and US multi-modal image-guided navigation system with a needle manipulator to enable US-guided applicator placement during MR imaging (MRI)-guided percutaneous tumor ablation.

METHODS

The MRI-compatible needle manipulator with US probe was installed adjacent to a 3 Tesla MRI scanner patient table. Coordinate systems for the MR image, patient table, manipulator, and US probe were all registered using an optical tracking sensor. The patient was initially scanned in the MRI scanner bore for planning and then moved outside the bore for treatment. Needle insertion was guided by real-time US imaging fused with the reformatted static MR image to enhance soft tissue contrast. Feasibility, targeting accuracy, and MR compatibility of the system were evaluated using a bovine liver and agar phantoms.

RESULTS

Targeting error for 50 needle insertions was 1.6 ± 0.6 mm (mean ± standard deviation). The experiment confirmed that fused MR and US images provided real-time needle localization against static MR images with soft tissue contrast.

CONCLUSIONS

The proposed MR and US multi-modal image-guided navigation system using a needle manipulator enabled accurate needle insertion by taking advantage of static MR and real-time US images simultaneously. Real-time visualization helped determine needle depth, tissue monitoring surrounding the needle path, target organ shifts, and needle deviation from the path.

Magnetically Actuated Soft Capsule Endoscope for Fine-Needle Biopsy

Wireless capsule endoscopes have revolutionized diagnostic procedures in the gastrointestinal (GI) tract by minimizing discomfort and trauma. Biopsy procedures, which are often necessary for a confirmed diagnosis of an illness, have been incorporated recently into robotic capsule endoscopes to improve their diagnostic functionality beyond only imaging. However, capsule robots to date have only been able to acquire biopsy samples of superficial tissues of the GI tract, which could generate false-negative diagnostic results if the diseased tissue is under the surface of the GI tract. To improve their diagnostic accuracy for submucosal tumors/diseases, we propose a magnetically actuated soft robotic capsule robot, which takes biopsy samples in a deep tissue of a stomach using the fine-needle biopsy technique. We present the design, control, and human-machine interfacing methods for the fine-needle biopsy capsule robot. Ex vivo experiments in a porcine stomach show 85% yield for the biopsy of phantom tumors located underneath the first layers of the stomach wall.

Robotic Transrectal Ultrasound Guided Prostate Biopsy

We present a robot-assisted approach for transrectal ultrasound (TRUS) guided prostate biopsy. The robot is a hands-free probe manipulator that moves the probe with the same 4 DoF that are used manually. Software was developed for three-dimensional (3-D) imaging, biopsy planning, robot control, and navigation. Methods to minimize the deformation of the prostate caused by the probe at 3-D imaging and needle targeting were developed to reduce biopsy targeting errors. We also present a prostate coordinate system (PCS). The PCS helps defining a systematic biopsy plan without the need for prostate segmentation. Comprehensive tests were performed, including two bench tests, one imaging test, two in vitro targeting tests, and an IRB-approved clinical trial on five patients. Preclinical tests showed that image-based needle targeting can be accomplished with accuracy on the order of 1 mm. Prostate biopsy can be accomplished with minimal TRUS pressure on the gland and submillimetric prostate deformations. All five clinical cases were successful with an average procedure time of 13 min and millimeter targeting accuracy. Hands-free TRUS operation, transrectal TRUS guided prostate biopsy with minimal prostate deformations, and the PCS-based biopsy plan are novel methods. Robot-assisted prostate biopsy is safe and feasible. Accurate needle targeting has the potential to increase the detection of clinically significant prostate cancer.

Medical Robotics in Bone Fracture Reduction Surgery: A Review

Since the advantages of precise operation and effective reduction of radiation, robots have become one of the best choices for solving the defects of traditional fracture reduction surgery. This paper focuses on the application of robots in fracture reduction surgery, design of the mechanism, navigation technology, robotic control, interaction technology, and the bone-robot connection technology. Through literature review, the problems in current fracture reduction robot and its future development are discussed.

Use of a Force-Torque Sensor for Self-Calibration of a 6-DOF Medical Robot

The aim of this paper is to improve the position accuracy of a six degree of freedom medical robot. The improvement in accuracy is achieved without the use of any external measurement device. Instead, this work presents a novel calibration approach based on using an embedded force-torque sensor to identify the robot’s kinematic parameters and thereby enhance the positioning accuracy. A simulation study demonstrated that our calibration approach is effective, whether or not any measurement noise is present: the position error is improved, inside the robot target workspace, from 12 mm to 0.320 mm, for the maximum values, and from 9 mm to 0.2771 mm, for the mean errors.

Body-mounted robotic instrument guide for image-guided cryotherapy of renal cancer

PURPOSE

Image-guided cryotherapy of renal cancer is an emerging alternative to surgical nephrectomy, particularly for those who cannot sustain the physical burden of surgery. It is well known that the outcome of this therapy depends on the accurate placement of the cryotherapy probe. Therefore, a robotic instrument guide may help physicians aim the cryotherapy probe precisely to maximize the efficacy of the treatment and avoid damage to critical surrounding structures. The objective of this paper was to propose a robotic instrument guide for orienting cryotherapy probes in image-guided cryotherapy of renal cancers. The authors propose a body-mounted robotic guide that is expected to be less susceptible to guidance errors caused by the patient's whole body motion.

METHODS

Keeping the device's minimal footprint in mind, the authors developed and validated a body-mounted, robotic instrument guide that can maintain the geometrical relationship between the device and the patient's body, even in the presence of the patient's frequent body motions. The guide can orient the cryotherapy probe with the skin incision point as the remote-center-of-motion. The authors' validation studies included an evaluation of the mechanical accuracy and position repeatability of the robotic instrument guide. The authors also performed a mock MRI-guided cryotherapy procedure with a phantom to compare the advantage of robotically assisted probe replacements over a free-hand approach, by introducing organ motions to investigate their effects on the accurate placement of the cryotherapy probe. Measurements collected for performance analysis included accuracy and time taken for probe placements. Multivariate analysis was performed to assess if either or both organ motion and the robotic guide impacted these measurements.

RESULTS

The mechanical accuracy and position repeatability of the probe placement using the robotic instrument guide were 0.3 and 0.1 mm, respectively, at a depth of 80 mm. The phantom test indicated that the accuracy of probe placement was significantly better with the robotic instrument guide (4.1 mm) than without the guide (6.3 mm, p<0.001), even in the presence of body motion. When independent organ motion was artificially added, in addition to body motion, the advantage of accurate probe placement using the robotic instrument guide disappeared statistically [i.e., 6.0 mm with the robotic guide and 5.9 mm without the robotic guide (p = 0.906)]. When the robotic instrument guide was used, the total time required to complete the procedure was reduced from 19.6 to 12.7 min (p<0.001). Multivariable analysis indicated that the robotic instrument guide, not the organ motion, was the cause of statistical significance. The statistical power the authors obtained was 88% in accuracy assessment and 99% higher in duration measurement.

CONCLUSIONS

The body-mounted robotic instrument guide allows positioning of the probe during image-guided cryotherapy of renal cancer and was done in fewer attempts and in less time than the free-hand approach. The accuracy of the placement of the cryotherapy probe was better using the robotic instrument guide than without the guide when no organ motion was present. The accuracy between the robotic and free-hand approach becomes comparable when organ motion was present.

Endocavity Ultrasound Probe Manipulators

We developed two similar structure manipulators for medical endocavity ultrasound probes with 3 and 4 degrees of freedom (DoF). These robots allow scanning with ultrasound for 3-D imaging and enable robot-assisted image-guided procedures. Both robots use remote center of motion kinematics, characteristic of medical robots. The 4-DoF robot provides unrestricted manipulation of the endocavity probe. With the 3-DoF robot the insertion motion of the probe must be adjusted manually, but the device is simpler and may also be used to manipulate external-body probes. The robots enabled a novel surgical approach of using intraoperative image-based navigation during robot-assisted laparoscopic prostatectomy (RALP), performed with concurrent use of two robotic systems (Tandem, T-RALP). Thus far, a clinical trial for evaluation of safety and feasibility has been performed successfully on 46 patients. This paper describes the architecture and design of the robots, the two prototypes, control features related to safety, preclinical experiments, and the T-RALP procedure.

Application study of medical robots in vascular intervention

BACKGROUND

Based on the background of minimally invasive surgery and applications of medical robots, a vascular interventional robotic system has been developed that can be used in the field of vascular intervention.

METHODS

The robotic system comprises a propulsion system, an image navigation system and a virtual surgery training system. Integration of the three systems constitutes a vascular intervention prototype robotic system used to carry out in vitro vascular intervention and animal experiments.

RESULTS

On a transparent glass vascular model, a catheter was shown to enter an arbitrary branch of the vascular model with catheter motion meeting the requirements of clinical vascular intervention surgery (VIS); i.e. error band of catheter motion < 0.5 mm. In the animal experiments, 1.33-2.00 mm (4F-6F) diameter catheters were selectively inserted successfully into predefined targets in the animal, such as the renal, cardiovascular and cerebrovascular artery. Compared with conventional manual surgery, the time for robotic surgery is a little longer. There were no operative complications in the animal experiments.

CONCLUSIONS

These simulation and animal study results demonstrate that this vascular interventional robotic system allows doctors to perform angiography remotely and prevents them from radiation exposure. The system may be the basis for further clinical applications of vascular intervention.