PedBotLab: A Novel Video Game-Based Robotic Ankle Platform Created for Therapeutic Exercise for Children With Neurological Impairments.

AIMS: Assess the potential benefits of using PedBotLab, a clinic based robotic ankle platform with integrated video game software, to improve ankle active and passive range of motion, strength, selective motor control, gait efficiency, and balance. METHODS: Ten participants with static neurological injuries and independent ambulation participated in a 10-week pilot study (Pro00013680) to assess feasibility and efficacy of PedBotLab as a therapeutic device twice weekly. Isometric ankle strength, passive and active ankle range of motion, plantarflexor spasticity, selective motor control of the lower extremity, balance, and gait speed were measured pre- and post-trial. RESULTS: Statistically significant improvements were seen in flexibility, active range of motion, and strength in multiple planes of ankle motion. Ankle dorsiflexion with knee flexion and knee extension demonstrated statistically significant results in all outcome measures. No significant changes were observed in gait speed outcomes. CONCLUSIONS: The use of PedbotLab can lead to improvements in ankle strength, flexibility, and active range of motion for children with static neurological injuries. Future studies aim to evaluate the effect on gait quality and work toward developing a home-based device.

Evaluation of a novel MRI-safe needle guidance toolkit for streamlined arthrography procedures.

Currently, Magnetic Resonance arthrography procedures require two rooms and two imaging modalities: fluoroscopically guided needle insertion in a fluoroscopy suite, followed by diagnostic MRI in a separate MRI suite. The use of fluoroscopy for needle placement exposes patients to ionizing radiation, which is an important concern, especially in pediatrics. The need for two different rooms and coordinating times for these rooms complicates hospital resource scheduling and logistics. In addition, the added delays could expose younger children to additional risks associated with the use of general anesthesia. To address these issues, we propose a new technique to streamline the arthrography procedure. Our proposed technology aims to eliminate exposure to ionizing radiation and to streamline arthrography procedures that are conducted solely under MRI. This toolkit consists of a 3D slicer-based user interface, a spatially unique silicone grid template, and a hand-held needle guidance device. Together, these tools are intended to simplify and shorten the procedure while maintaining accuracy and precision comparable to the current gold standard procedure. In our cadaver study, we evaluated the feasibility and accuracy of our novel MRI-safe Needle Guidance Toolkit for MRI arthrography procedures, achieving an average targeting accuracy of 3.2 ± 1.0 mm. The results presented in this study showed the feasibility and promise of our novel MRI-safe needle guidance toolkit for arthrography procedures.

Toward Robust Partial-Image Based Template Matching Techniques for MRI-Guided Interventions.

We have developed an MRI-safe needle guidance toolkit for MRI-guided interventions intended to enable accurate positioning for needle-based procedures. The toolkit allows intuitive and accurate needle angulation and entry point positioning according to an MRI-based plan, using a flexible, patterned silicone 2D grid. The toolkit automatically matches the grid on MRI planning images with a physical silicon grid placed conformally on the patient's skin and provides the Interventional Radiologist an easy-to-use guide showing the needle entry point on the silicon grid as well as needle angle information. The radiologist can use this guide along with a 2-degree-of-freedom (rotation and angulation relative to the entry point) hand-held needle guide to place the needle into the anatomy of interest. The initial application that we are considering for this toolkit is arthrography, a diagnostic procedure to evaluate the joint space condition. However, this toolkit could be used for any needle-based and percutaneous procedures such as MRI-guided biopsy and facet joint injection. For matching the images, we adopt a transformation parameter estimation technique using the phase-only correlation method in the frequency domain. We investigated the robustness of this method against rotation, displacement, and Rician noise. The algorithm was able to successfully match all the dataset images. We also investigated the accuracy of identifying the entry point from registered template images as a prerequisite for a future targeting study. Application of the template matching algorithm to locate the needle entry points within the MRI dataset resulted in an average entry point location estimation accuracy of 0.12 ±0.2 mm. This promising result motivates a more detailed assessment of this algorithm in the future including a targeting study on a silicon phantom with embedded plastic targets to investigate the end-to-end accuracy of this automatic template matching algorithm in the interventional MRI room.

Validation of a novel path planner for stereotactic neurosurgical interventions-A retrospective clinical study.

BACKGROUND: The gold standard workflow for targeting structures in the brain involves manual path planning. This preoperative manual path planning is very time-intensive and laborious, especially when some outcome measures such as maximum ablation and penetration depth has to be optimised. METHODS: Our novel path planner generates an optimal path which maximises the hippocampus penetration and distance from critical structures using a precomputed cost map and a reward map. RESULTS: The average penetration ratio for 12 cases is 88.13 ± 23.23% for a resolution of 1° and a safety margin of 1 mm. Average run time for the path planner based on 1° resolution was 1.99 ± 0.68 min. CONCLUSIONS: Results show that the algorithm can generate safe and clinically relevant paths with a quantitative representation of the penetration depth and is faster than the average reported time for manual path planning.

PedBotHome: A Video Game-Based Robotic Ankle Device Created for Home Exercise in Children With Neurological Impairments.

PURPOSE: This pilot study assesses the feasibility of using PedBotHome to promote adherence to a home exercise program, the ability of the device to withstand frequent use, and changes in participant ankle mobility.PedBotHome is a robotic ankle device with integrated video game software designed to improve ankle mobility in children with cerebral palsy. METHODS: Eight participants enrolled in a 28-day trial of PedBotHome. Ankle strength, range of motion, and plantar flexor spasticity were measured pre- and posttrial. Performance was monitored remotely, and game settings were modified weekly by physical therapists. RESULTS: Four participants met the study goal of 20 days of use. There were statistically significant improvements in ankle strength, spasticity, and range of motion. CONCLUSIONS: PedBotHome is a feasible device to engage children with static neurological injuries in ankle home exercise. This pilot study expands the paradigm for future innovative home-based robotic rehabilitation.

Body-Mounted Robotic System for MRI-Guided Shoulder Arthrography: Cadaver and Clinical Workflow Studies.

This paper presents an intraoperative MRI-guided, patient-mounted robotic system for shoulder arthrography procedures in pediatric patients. The robot is designed to be compact and lightweight and is constructed with nonmagnetic materials for MRI safety. Our goal is to transform the current two-step arthrography procedure (CT/x-ray-guided needle insertion followed by diagnostic MRI) into a streamlined single-step ionizing radiation-free procedure under MRI guidance. The MR-conditional robot was evaluated in a Thiel embalmed cadaver study and healthy volunteer studies. The robot was attached to the shoulder using straps and ten locations in the shoulder joint space were selected as targets. For the first target, contrast agent (saline) was injected to complete the clinical workflow. After each targeting attempt, a confirmation scan was acquired to analyze the needle placement accuracy. During the volunteer studies, a more comfortable and ergonomic shoulder brace was used, and the complete clinical workflow was followed to measure the total procedure time. In the cadaver study, the needle was successfully placed in the shoulder joint space in all the targeting attempts with translational and rotational accuracy of 2.07 ± 1.22 mm and 1.46 ± 1.06 degrees, respectively. The total time for the entire procedure was 94 min and the average time for each targeting attempt was 20 min in the cadaver study, while the average time for the entire workflow for the volunteer studies was 36 min. No image quality degradation due to the presence of the robot was detected. This Thiel-embalmed cadaver study along with the clinical workflow studies on human volunteers demonstrated the feasibility of using an MR-conditional, patient-mounted robotic system for MRI-guided shoulder arthrography procedure. Future work will be focused on moving the technology to clinical practice.

MR-Conditional Actuations: A Review.

Magnetic resonance imaging (MRI) is one of the most prevailing technologies to enable noninvasive and radiation-free soft tissue imaging. Operating a robotic device under MRI guidance is an active research area that has the potential to provide efficient and precise surgical therapies. MR-conditional actuators that can safely drive these robotic devices without causing safety hazards or adversely affecting the image quality are crucial for the development of MR-guided robotic devices. This paper aims to summarize recent advances in actuation methods for MR-guided robots and each MR-conditional actuator was reviewed based on its working principles, construction materials, the noteworthy features, and corresponding robotic application systems, if any. Primary characteristics, such as torque, force, accuracy, and signal-to-noise ratio (SNR) variation due to the variance of the actuator, are also covered. This paper concludes with a perspective on the current development and future of MR-conditional actuators.

Toward Evaluation of the Subjective Experience of a General Class of User-Controlled, Robot-Mediated Rehabilitation Technologies for Children with Neuromotor Disability.

Technological advances in game-mediated robotics provide an opportunity to engage children with cerebral palsy (CP) and other neuromotor disabilities in more frequent and intensive therapy by making personalized, programmed interventions available 24/7 in children's homes. Though shown to be clinically effective and feasible to produce, little is known of the subjective factors impacting acceptance of what we term assistive/rehabilitative (A/R) gamebots by their target populations. This research describes the conceptualization phase of an effort to develop a valid and reliable instrument to guide the design of A/R gamebots. We conducted in-depth interviews with 8 children with CP and their families who had trialed an exemplar A/R gamebot, PedBotHome, for 28 days in their homes. The goal was to understand how existing theories and instruments were either appropriate or inappropriate for measuring the subjective experience of A/R gamebots. Key findings were the importance of differentiating the use case of therapy from that of assistance in rehabilitative technology assessment, the need to incorporate the differing perspectives of children with CP and those of their parents into A/R gamebot evaluation, and the potential conflict between the goals of preserving the quality of the experience of game play for the child while also optimizing the intensity and duration of therapy provided during play.

Body-Mounted Robotics for Interventional MRI Procedures.

This paper reports the development and initial cadaveric evaluation of a robotic framework for MRI-guided interventions using a body-mounted approach. The framework is developed based on modular design principles. The framework consists of a body-mounted needle placement manipulator, robot control software, robot controller, interventional planning workstation, and MRI scanner. The framework is modular in the sense that all components are connected independently, making it readily extensible and reconfigurable for supporting the clinical workflow of various interventional MRI procedures. Based on this framework we developed two body-mounted robots for musculoskeletal procedures. The first robot is a four-degree of freedom system called ArthroBot for shoulder arthrography in pediatric patients. The second robot is a six-degree of freedom system called PainBot for perineural injections used to treat pain in adult and pediatric patients. Body-mounted robots are designed with compact and lightweight structure so that they can be attached directly to the patient, which minimizes the effect of patient motion by allowing the robot to move with the patient. A dedicated clinical workflow is proposed for the MRI-guided musculoskeletal procedures using body-mounted robots. Initial cadaveric evaluations of both systems were performed to verify the feasibility of the systems and validate the clinical workflow.

Pedbothome: Robotically-Assisted Ankle Rehabilitation System For Children With Cerebral Palsy.

Our research team has developed two versions of an ankle robot for children with cerebral palsy. Both devices provide three degrees of freedom and are connected to an airplane video game. The child uses his/her foot as the controller for the plane and attempts to fly through a series of hoops arranged to manipulate the foot across the ankle joint. The first device is for lab-based therapy and four children have completed 20 sessions each with the device. The second device is for home-based therapy and two children have completed a 28-day trial using the device at home. Both studies were done under Institutional Review Board approval and all participants improved ankle range of motion. Further studies are ongoing to gather more data and validate the results.

Preclinical evaluation of an integrated robotic system for magnetic resonance imaging guided shoulder arthrography.

Shoulder arthrography is a diagnostic procedure which involves injecting a contrast agent into the joint space for enhanced visualization of anatomical structures. Typically, a contrast agent is injected under fluoroscopy or computed tomography (CT) guidance, resulting in exposure to ionizing radiation, which should be avoided especially in pediatric patients. The patient then waits for the next available magnetic resonance imaging (MRI) slot for obtaining high-resolution anatomical images for diagnosis, which can result in long procedure times. Performing the contrast agent injection under MRI guidance could overcome both these issues. However, it comes with the challenges of the MRI environment including high magnetic field strength, limited ergonomic patient access, and lack of real-time needle guidance. We present the development of an integrated robotic system to perform shoulder arthrography procedures under intraoperative MRI guidance, eliminating fluoroscopy/CT guidance and patient transportation from the fluoroscopy/CT room to the MRI suite. The average accuracy of the robotic manipulator in benchtop experiments is 0.90 mm and 1.04 deg, whereas the average accuracy of the integrated system in MRI phantom experiments is 1.92 mm and 1.28 deg at the needle tip. Based on the American Society for Testing and Materials (ASTM) tests performed, the system is classified as MR conditional.

Remotely Actuated Needle Driving Device for MRI-Guided Percutaneous Interventions: Force and Accuracy Evaluation.

This paper presents a 2 degrees-of-freedom (DOF) remotely actuated needle driving device for Magnetic Resonance Imaging (MRI) guided pain injections. The device is evaluated in phantom studies under real-time MRI guidance. The force and torque asserted by the device on the 4-DOF base robot are measured. The needle driving device consists of a needle driver, a 1.2-meter long beaded chain transmission, an actuation box, a robot controller and a Graphical User Interface (GUI). The needle driver can fit within a typical MRI scanner bore and is remotely actuated at the end of the MRI table through a novel beaded chain transmission. The remote actuation mechanism significantly reduces the weight and size of the needle driver at the patient end as well as the artifacts introduced by the motors. The clinician can manually steer the needle by rotating the knobs on the actuation box or remotely through a software interface in the MRI console room. The force and torque resulting from the needle driver in various configurations both in static and dynamic status were measured and reported. An accuracy experiment in the MRI environment under real-time image feedback demonstrates a small mean targeting error (<; 1.5 mm) in a phantom study.

Remotely Actuated Needle Driving Device for MRI-Guided Percutaneous Interventions.

In this paper we introduce a remotely actuated MRI-compatible needle driving device for pain injections in the lower back. This device is able to manipulate the needle inside the closed-bore MRI scanner under the control of the interventional radiologist inside both the scanner room and the console room. The device consists of a 2 degrees of freedom (DOF) needle driver and an actuation box. The 2-DOF needle driver is placed inside the scanner bore and driven by the actuation box settled at the end of the table through a beaded chain transmission. This novel remote actuation design could reduce the weight and profile of the needle driver that is mounted on the patient, as well as minimize the potential imaging noise introduced by the actuation electronics. The actuation box is designed to perform needle intervention in both manual and motorized fashion by utilizing a mode switch mechanism. A mechanical hard stop is also incorporated to improve the device's safety. The bench-top accuracy evaluation of the device demonstrated a small mean needle placement error (< 1 mm) in a phantom study.

Development of a shoulder-mounted robot for MRI-guided needle placement: phantom study.

PURPOSE: This paper presents new quantitative data on a signal-to-noise ratio (SNR) study, distortion study, and targeting accuracy phantom study for our patient-mounted robot (called Arthrobot). Arthrobot was developed as an MRI-guided needle placement device for diagnostic and interventional procedures such as arthrography. METHODS: We present the robot design and inverse kinematics. Quantitative assessment results for SNR and distortion study are also reported. A respiratory motion study was conducted to evaluate the shoulder mounting method. A phantom study was conducted to investigate end-to-end targeting accuracy. Combined error considering targeting accuracy, respiratory motion, and structure deformation is also reported. RESULTS: The SNR study showed that the SNR changes only 2% when the unpowered robot was placed on top of a standard water phantom. The distortion study showed that the maximum distortion from the ground truth was 2.57%. The average error associated with respiratory motion was 1.32 mm with standard deviation of 1.38 mm. Results of gel phantom targeting studies indicate average needle placement error of 1.64 mm, with a standard deviation of 0.90 mm. CONCLUSIONS: Noise and distortion of the MR images were not significant, and image quality in the presence of the robot was satisfactory for MRI-guided targeting. Combined average total error, adding mounting stability errors and structure deformation errors to targeting error, is estimated to be 3.4 mm with a standard deviation of 1.65 mm. In clinical practice, needle placement accuracy under 5 mm is considered sufficient for successful joint injection during shoulder arthrography. Therefore, for the intended clinical procedure, these results indicate that Arthrobot has sufficient positioning accuracy.

MRI Robots for Needle-Based Interventions: Systems and Technology.

Magnetic resonance imaging (MRI) provides high-quality soft-tissue images of anatomical structures and radiation free imaging. The research community has focused on establishing new workflows, developing new technology, and creating robotic devices to change an MRI room from a solely diagnostic room to an interventional suite, where diagnosis and intervention can both be done in the same room. Closed bore MRI scanners provide limited access for interventional procedures using intraoperative imaging. MRI robots could improve access and procedure accuracy. Different research groups have focused on different technology aspects and anatomical structures. This paper presents the results of a systematic search of MRI robots for needle-based interventions. We report the most recent advances in the field, present relevant technologies, and discuss possible future advances. This survey shows that robotic-assisted MRI-guided prostate biopsy has received the most interest from the research community to date. Multiple successful clinical experiments have been reported in recent years that show great promise. However, in general the field of MRI robotic systems is still in the early stage. The continued development of these systems, along with partnerships with commercial vendors to bring this technology to market, is encouraged to create new and improved treatment opportunities for future patients.

Robotically Assisted Long Bone Biopsy Under MRI Imaging: Workflow and Preclinical Study.

RATIONALE AND OBJECTIVES: Our research team has developed a magnetic resonance imaging (MRI)-compatible robot for long bone biopsy. The robot is intended to enable a new workflow for bone biopsy in pediatrics under MRI imaging. Our long-term objectives are to minimize trauma and eliminate radiation exposure when diagnosing children with bone cancers and bone infections. This article presents our robotic systems, phantom accuracy studies, and workflow analysis. MATERIALS AND METHODS: This section describes several aspects of our work including the envisioned clinical workflow, the MRI-compatible robot, and the experimental setup. The workflow consists of five steps and is intended to enable the entire procedure to be completed in the MRI suite. The MRI-compatible robot is MR Safe, has 3 degrees of freedom, and a remote center of motion mechanism for orienting a needle guide. The accuracy study was done in a Siemens Aera 1.5T scanner with a long bone phantom. Four targeting holes were drilled in the phantom. RESULTS: Each target was approached twice at slightly oblique angles using the robot needle guide for a total of eight attempts. A workflow analysis showed the average time for each targeting attempt was 32 minutes, including robot setup time. The average 3D targeting error was 1.39 mm with a standard deviation of 0.40 mm. All of the targets were successfully reached. CONCLUSION: The results showed the ability of the robotic system in assisting the radiologist to precisely target a bone phantom in the MRI environment. The robot system has several potential advantages for clinical application, including the ability to work at the MRI isocenter and serve as a steady and precise guide.

Repair of Tympanic Membrane Perforations with Customized Bioprinted Ear Grafts Using Chinchilla Models.

The goal of this work is to develop an innovative method that combines bioprinting and endoscopic imaging to repair tympanic membrane perforations (TMPs). TMPs are a serious health issue because they can lead to both conductive hearing loss and repeated otitis media. TMPs occur in 3-5% of cases after ear tube placement, as well as in cases of acute otitis media (the second most common infection in pediatrics), chronic otitis media with or without cholesteatoma, or as a result of barotrauma to the ear. About 55,000 tympanoplasties, the surgery performed to reconstruct TMPs, are performed every year, and the commonly used cartilage grafting technique has a success rate between 43% and 100%. This wide variability in successful tympanoplasty indicates that the current approach relies heavily on the skill of the surgeon to carve the shield graft into the shape of the TMP, which can be extremely difficult because of the perforation's irregular shape. To this end, we hypothesized that patient specific acellular grafts can be bioprinted to repair TMPs. In vitro data demonstrated that our approach resulted in excellent wound healing responses (e.g., cell invasion and proliferations) using our bioprinted gelatin methacrylate constructs. Based on these results, we then bioprinted customized acellular grafts to treat TMP based on endoscopic imaging of the perforation and demonstrated improved TMP healing in a chinchilla study. These ear graft techniques could transform clinical practice by eliminating the need for hand-carved grafts. To our knowledge, this is the first proof of concept of using bioprinting and endoscopic imaging to fabricate customized grafts to treat tissue perforations. This technology could be transferred to other medical pathologies and be used to rapidly scan internal organs such as intestines for microperforations, brain covering (Dura mater) for determination of sites of potential cerebrospinal fluid leaks, and vascular systems to determine arterial wall damage before aneurysm rupture in strokes.

Body-Mounted Robot for Image-Guided Percutaneous Interventions: Mechanical Design and Preliminary Accuracy Evaluation.

This paper presents a body-mounted, four degree-of-freedom (4-DOF) parallel mechanism robot for image-guided percutaneous interventions. The design of the robot is optimized to be light weight and compact such that it could be mounted to the patient body. It has a modular design that can be adopted for assisting various image-guided, needle-based percutaneous interventions such as arthrography, biopsy and brachytherapy seed placement. The robot mechanism and the control system are designed and manufactured with components compatible with imaging modalities including Magnetic Resonance Imaging (MRI) and Computed Tomography (CT). The current version of the robot presented in this paper is optimized for shoulder arthrography under MRI guidance; a Z-shaped fiducial frame is attached to the robot, providing accurate and repeatable robot registration with the MR scanner coordinate system. Here we present the mechanical design of the manipulator, robot kinematics, robot calibration procedure, and preliminary bench-top accuracy assessment. The bench-top accuracy evaluation of the robotic manipulator shows average translational error of 1.01 mm and 0.96 mm in X and Z axes, respectively, and average rotational error of 3.06 degrees and 2.07 degrees about the X and Z axes, respectively.

A new 4-DOF parallel robot for MRI-guided percutaneous interventions: Kinematic analysis.

In this paper, we present the concept of a novel 4-DOF parallel robot for MRI-guided percutaneous interventions. This system belongs to the class of patient-mounted robots, with two parallel circular stages along which two actuating joints move. As a first step, we present the concept of the robot and its kinematic analysis. This robot has the potential of increased rigidity and reduced inertial effect compared to its predecessor. It also minimizes the number of moving components, which enhances safety during the robot's operation.

External force estimation and implementation in robotically assisted minimally invasive surgery.

BACKGROUND: Robotically assisted minimally invasive surgery can offer many benefits over open surgery and laparoscopic minimally invasive surgery. However, currently, there is no force sensing and force feedback. METHODS: This research was implemented using the da Vinci research kit. An external force estimation and implementation method was proposed based on dynamics and motor currents. The dynamics of the Patient Side Manipulator was modeled. The dynamic model was linearly parameterized. The estimation principle of external force was derived. The dynamic parameters were experimentally identified using a least squares method. RESULTS: Several experiments including dynamic parameter identification, joint torque estimation, and external force estimation were performed. The results showed that the proposed method could implement force estimation without using a force sensor. CONCLUSIONS: The force estimation method was proposed and implemented and experimental results showed the method worked and was feasible. This method could be used for force sensing in minimally invasive surgical robotics in the future.