Orthopedic Biomechanics
Javad Mortazavi; Farzam Farahmand; Saeed Behzadipour; Ali Yeganeh
Volume 12, Issue 1 , June 2018, , Pages 63-74
Abstract
Intramedullary nailing is a common technique for treatment of femoral shaft fractures. Nail deformation after insertion into the bone, makes the distal hole locking a challenging task for the surgeon. The proximally mounted targeting systems for locating the position of the distal hole become ineffective ...
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Intramedullary nailing is a common technique for treatment of femoral shaft fractures. Nail deformation after insertion into the bone, makes the distal hole locking a challenging task for the surgeon. The proximally mounted targeting systems for locating the position of the distal hole become ineffective due to the nail deformation. The previous image-based techniques have often considered the shape of the distal end of the nail only to find the position and direction of the distal hole. The purpose of this study was to evaluate the hypothesis of possibility of locating the position of the distal hole using mechanical modeling and radiography data simultaneously. In the proposed method, according to the nail geometry (length to diameter ratio between 25 and 50), an Euler-Bernoulli beam model is used to simulate the mechanical behavior of the nail and calculate its deformation pattern. Then, by registering the deformation pattern with the sagittal radiography image of the nail, using iterative closest point algorithm, the nail deformation and the position of the distal hole are predicted. In order to evaluate the research hypothesis, a number of experiments were performed on five cadaveric femurs and the predicted and actual positions of the distal hole were compared. Results indicated that by using mechanical modeling and the imaging data of the nail curvature, the position of the distal hole could be predicted with a mean error of 0.84 mm and a maximum error of 1.3 mm. It is expected that by combining the proposed method with the image-based techniques, which make use of the shape data of the hole, a sub-millimeter error in locating the distal hole could be achieved in future.
Medical Robotics / Bio-Robotics
Mojtaba Sharifi; Saeid Behzadipour; Hasan Salarieh; Farzam Farahmand
Volume 9, Issue 1 , April 2015, , Pages 85-98
Abstract
In this paper, a transparent bilateral controller is developed for the control of telesurgery systems that have physical interactions with soft tissue. In this control method, the parameters of a viscoelastic model of the soft tissue are estimated during its interaction with the slave robot using an ...
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In this paper, a transparent bilateral controller is developed for the control of telesurgery systems that have physical interactions with soft tissue. In this control method, the parameters of a viscoelastic model of the soft tissue are estimated during its interaction with the slave robot using an on-line identification method. These estimated parameters are used inanimpedance control of the master robot which is in contact with the surgeon. Also, the slave robot tracks the master robot position using a tracking controller. Accordingly, it is shown that the transparency of the teleoperation system is obtained by estimating and realizing the dynamic parameters of the tissue for the master robot and providing the position tracking performance for the slave robot. The stability, and the position and force tracking performances are proved using the Lyapunov theorem. Moreover, the effectiveness of the proposed transparent bilateral controller is investigated by simulations performed on a piece of beef (as the soft tissue) using a two DOF robot with nonlinear dynamics. The proposed control strategy can be used in telesurgery, telesonography and telerehabilitation systems in which the robot interacts with soft tissues.
