Innovation of a Humanoid Robotic Wrist

Microbial Biotechnolog

BIOMECHANICS OF THE DISTAL RADIOULNAR JOINT WITH A MALALIGNED DISTAL RADIUS

Distal radius fractures are the most common fractures in humans and frequently have suboptimal outcomes, fostering considerable discussion with regard to treatment. This body of work was based on the postulate that quantifying the biomechanics, specifically the kinematics and loading of the distal radial ulnar joint (DRUJ) before and after simulated distal radius malalignment would provide important new information to the treatment of these fractures. Furthermore, an investigation into the effect of soft- tissues would further the biomechanical understanding of these disorders. In light of the foregoing, a distal radial implant to simulate malalignment in vitro was designed and developed. An instrumented ulnar load cell was also employed to measure the load transfer at the distal ulna. A series of in vitro studies employing simulated muscle loading to produce forearm rotation were conducted using an upper extremity joint simulator. The distal radial implant and ulnar load cell were implanted and an electromagnetic tracking device was used to record the motion of the radius and ulna. The kinematics and joint loading of the native forearm were measured at the beginning of each testing and compared with simulated distal radial deformities. As the severity of distal radial deformities worsened, a gradual loss of forearm rotation, a progressive change in kinematic patterns and an increasing alteration in the load transfer at the distal ulna was quantified. No absolute threshold in distal radial deformity was noted before joint dysfunction was markedly disturbed. This is in agreement with clinical findings as patients with malunited Colles’ fractures often present iii with reduced range of motion, joint stiffness and pain, suggesting that this pain may be in part be due to the increase in joint loading required to generate forearm rotation. Sectioning the triangular fibrocartilage complex, which is commonly injured in association with distal radial fractures, restored rotation and reduced the loading on the joint; however, this resulted in greater alteration of DRUJ kinematics. In conclusion, this work has provided valuable information to assist biomechanists and clinicians in understanding the implication of both osseous and soft tissue disorders of the distal radius and provides better evidence to improve patient outcomes

The Development and Application of a Forearm Simulator to Investigate Radial Head Biomechanics

The forearm is a complex articular unit, with poorly understood biomechanics. A novel forearm simulator to facilitate physiologic testing of cadavers for multiple clinical scenarios was designed, manufactured and validated. A number of outcome measurements were potentiated including the forearm’s resistance to rotation, radiocapitellar contact pressure and area as well as IOM loads. Testing of changes to forearm biomechanics due to radial head excision and variations of radial head arthroplasty dimensions was conducted. Radial head arthroplasty using the correct radial head length and diameter recreated the biomechanics of an intact forearm. Radial head excision as well an implant of non-anatomic length or diameter created abnormal radiocapitellar joint properties and load transfer within the forearm. The simulator had good repeatability and reproducibility. If radial head arthroplasty is clinically required, an implant that is similar in dimensions to the native radial head maintains native forearm biomechanics

Robotic System Development for Precision MRI-Guided Needle-Based Interventions

This dissertation describes the development of a methodology for implementing robotic systems for interventional procedures under intraoperative Magnetic Resonance Imaging (MRI) guidance. MRI is an ideal imaging modality for surgical guidance of diagnostic and therapeutic procedures, thanks to its ability to perform high resolution, real-time, and high soft tissue contrast imaging without ionizing radiation. However, the strong magnetic field and sensitivity to radio frequency signals, as well as tightly confined scanner bore render great challenges to developing robotic systems within MRI environment. Discussed are potential solutions to address engineering topics related to development of MRI-compatible electro-mechanical systems and modeling of steerable needle interventions. A robotic framework is developed based on a modular design approach, supporting varying MRI-guided interventional procedures, with stereotactic neurosurgery and prostate cancer therapy as two driving exemplary applications. A piezoelectrically actuated electro-mechanical system is designed to provide precise needle placement in the bore of the scanner under interactive MRI-guidance, while overcoming the challenges inherent to MRI-guided procedures. This work presents the development of the robotic system in the aspects of requirements definition, clinical work flow development, mechanism optimization, control system design and experimental evaluation. A steerable needle is beneficial for interventional procedures with its capability to produce curved path, avoiding anatomical obstacles or compensating for needle placement errors. Two kinds of steerable needles are discussed, i.e. asymmetric-tip needle and concentric-tube cannula. A novel Gaussian-based ContinUous Rotation and Variable-curvature (CURV) model is proposed to steer asymmetric-tip needle, which enables variable curvature of the needle trajectory with independent control of needle rotation and insertion. While concentric-tube cannula is suitable for clinical applications where a curved trajectory is needed without relying on tissue interaction force. This dissertation addresses fundamental challenges in developing and deploying MRI-compatible robotic systems, and enables the technologies for MRI-guided needle-based interventions. This study applied and evaluated these techniques to a system for prostate biopsy that is currently in clinical trials, developed a neurosurgery robot prototype for interstitial thermal therapy of brain cancer under MRI guidance, and demonstrated needle steering using both asymmetric tip and pre-bent concentric-tube cannula approaches on a testbed

Design of a Bio-Inspired 3D Orientation Coordinate System and Application in Robotised Tele-Sonography

International audienc

Development of an In-Vitro Passive and Active Motion Simulator for the Investigation of Shoulder Function and Kinematics

Injuries and degenerative diseases of the shoulder are common and may relate to the joint’s complex biomechanics, which rely primarily on soft tissues to achieve stability. Despite the prevalence of these disorders, there is little information about their effects on the biomechanics of the shoulder, and a lack of evidence with which to guide clinical practice. Insight into these disorders and their treatments can be gained through in-vitro biomechanical experiments where the achieved physiologic accuracy and repeatability directly influence their efficacy and impact. This work’s rationale was that developing a simulator with greater physiologic accuracy and testing capabilities would improve the quantification of biomechanical parameters. This dissertation describes the development and validation of a simulator capable of performing passive assessments, which use experimenter manipulation, and active assessments – produced through muscle loading. Respectively, these allow the assessment of functional parameters such as stability, and kinematic/kinetic parameters including joint loading. The passive functionality enables specimen motion to be precisely controlled through independent manipulation of each rotational degree of freedom (DOF). Compared to unassisted manipulation, the system improved accuracy and repeatability of positioning the specimen (by 205% & 163%, respectively), decreased variation in DOF that are to remain constant (by 6.8°), and improved achievement of predefined endpoints (by 21%). Additionally, implementing a scapular rotation mechanism improved the physiologic accuracy of simulation. This enabled the clarification of the effect of secondary musculature on shoulder function, and the comparison of two competing clinical reconstructive procedures for shoulder instability. This was the first shoulder system to use real time kinematic feedback and PID control to produce active motion, which achieved unmatched accuracy ( These developments can be a powerful tool for increasing our understanding of the shoulder and also to provide information which can assist surgeons and improve patient outcomes

Flexible robotic device for spinal surgery

Surgical robots have proliferated in recent years, with well-established benefits including: reduced patient trauma, shortened hospitalisation, and improved diagnostic accuracy and therapeutic outcome. Despite these benefits, many challenges in their development remain, including improved instrument control and ergonomics caused by rigid instrumentation and its associated fulcrum effect. Consequently, it is still extremely challenging to utilise such devices in cases that involve complex anatomical pathways such as the spinal column. The focus of this thesis is the development of a flexible robotic surgical cutting device capable of manoeuvring around the spinal column. The target application of the flexible surgical tool is the removal of cancerous tumours surrounding the spinal column, which cannot be excised completely using the straight surgical tools in use today; anterior and posterior sections of the spine must be accessible for complete tissue removal. A parallel robot platform with six degrees of freedom (6 DoFs) has been designed and fabricated to direct a flexible cutting tool to produce the necessary range of movements to reach anterior and posterior sections of the spinal column. A flexible water jet cutting system and a flexible mechanical drill, which may be assembled interchangeably with the flexible probe, have been developed and successfully tested experimentally. A model predicting the depth of cut by the water jet was developed and experimentally validated. A flexion probe that is able to guide the surgical cutting device around the spinal column has been fabricated and tested with human lumber model. Modelling and simulations show the capacity for the flexible surgical system to enable entering the posterior side of the human lumber model and bend around the vertebral body to reach the anterior side of the spinal column. A computer simulation with a full Graphical User Interface (GUI) was created and used to validate the system of inverse kinematic equations for the robot platform. The constraint controller and the inverse kinematics relations are both incorporated into the overall positional control structure of the robot, and have successfully established a haptic feedback controller for the 6 DoFs surgical probe, and effectively tested in vitro on spinal mock surgery. The flexible surgical system approached the surgery from the posterior side of the human lumber model and bend around the vertebral body to reach the anterior side of the spinal column. The flexible surgical robot removed 82% of mock cancerous tissue compared to 16% of tissue removed by the rigid tool.Open Acces