Clinical Experiences of Transforaminal Balloon Decompression for Patients with Spinal Stenosis

Lumbar spinal stenosis is a commonly treated with epidural injections of local anesthetics and corticosteroids, however, these therapies may relieve leg pain for weeks to months but do not influence functional status. Furthermore, the majority of patients report no substantial symptom change over the repeated treatment. Utilizing balloon catheters, we successfully treated with three patients who complained persistent symptoms despite repeated conventional steroid injections. Our results suggest that transforaminal decompression using a balloon catheter may have potential in the nonsurgical treatment of spinal stenosis by modifying the underlying pathophysiology

The NOGO Receptor NgR2, A Novel αVβ3 Integrin Effector, Induces Neuroendocrine Differentiation in Prostate Cancer

Androgen deprivation therapies aimed to target prostate cancer (PrCa) are only partially successful given the occurrence of neuroendocrine PrCa (NEPrCa), a highly aggressive and highly metastatic form of PrCa, for which there is no effective therapeutic approach. Our group has demonstrated that while absent in prostate adenocarcinoma, the αVβ3 integrin expression is increased during PrCa progression toward NEPrCa. Here, we show a novel pathway activated by αVβ3 that promotes NE differentiation (NED). This novel pathway requires the expression of a GPI-linked surface molecule, NgR2, also known as Nogo-66 receptor homolog 1. We show here that NgR2 is upregulated by αVβ3, to which it associates; we also show that it promotes NED and anchorage-independent growth, as well as a motile phenotype of PrCa cells. Given our observations that high levels of αVβ3 and, as shown here, of NgR2 are detected in human and mouse NEPrCa, our findings appear to be highly relevant to this aggressive and metastatic subtype of PrCa. This study is novel because NgR2 role has only minimally been investigated in cancer and has instead predominantly been analyzed in neurons. These data thus pave new avenues toward a comprehensive mechanistic understanding of integrin-directed signaling during PrCa progression toward a NE phenotype

In Vivo Estimation of Human Forearm and Wrist Dynamic Properties

It is important to estimate the 3 degree-of-freedom (DOF) impedance of human forearm and wrist (i.e., forearm prono-supination, and wrist flexion-extension and radial-ulnar deviation) in motor control and in the diagnosis of altered mechanical resistance following stroke. There is, however, a lack of methods to characterize 3 DOF impedance. Thus, we developed a reliable and accurate impedance estimation method, the distal internal model based impedance control (dIMBIC)-based method, to characterize the 3 DOF impedance, including cross-coupled terms between DOFs, for the first time. Its accuracy and reliability were experimentally validated using a robot with substantial nonlinear joint friction. The 3 DOF human forearm and wrist impedance of eight healthy subjects was reliably characterized, and its linear behavior was verified. Thus, the dIMBIC-based method can provide us with 3 DOF forearm and wrist impedance regardless of nonlinear robot joint friction. It is expected that, with the proposed method, the 3 DOF impedance estimation can promote motor control studies and complement the diagnosis of altered wrist and forearm resistance post-stroke by providing objective impedance estimates, including cross-coupled terms

Active compliance control for the rehabilitation robot with cable driven transmission

In this paper, we proposed a TDC based F/T sensorless active compliance control algorithm for a rehabilitation robot (KARES II). The preference of compliance of the disabled is presented by clinical testing at Korea National Rehabilitation Center with the disabled. The KARES II was designed to work 12 predefined tasks which are very essential for helping the disabled. Among the tasks, some contact tasks between the robot and the disabled exist. Therefore, TDC based F/T sensorless compliance control algorithm is developed for these tasks without additional cost. We verified the proposed algorithm with experiment. Also for the practical use, suitable compliance for contact tasks is chosen by clinical testing at Korea National Rehabilitation Center.clos

Stochastic estimation of human arm impedance under nonlinear friction in robot joints: a model study

The basic assumption of stochastic human arm impedance estimation methods is that the human arm and robot behave linearly for small perturbations. In the present work, the degree of influence of nonlinear friction in robot joints to the stochastic human arm impedance estimation is identified. Internal model based impedance control (IMBIC) is then proposed as a means of making the estimation accurate by compensating for the nonlinear friction. From simulations with a nonlinear Lugre friction model, it is observed that the reliability and accuracy of the estimation are severely degraded with nonlinear friction. In contrast, the combined use of stochastic estimation and IMBIC provides with accurate estimation results even with large friction. Furthermore, the performance of suggested method is independent of human arm and robot posture, and human arm impedance. Therefore, the IMBIC will be useful in measuring human arm impedance with conventional robot, as well as in designing a spatial impedance measuring robot, which requires gearing

Sensorless and modeless estimation of external force using time delay estimation: application to impedance control

This paper proposes an external force estimation algorithm that requires neither dynamical models nor force-torque (F/T) sensors. Considering cost reduction, 'indirect estimation' of external force can be preferable to 'direct sensing' of the force. However, the explicit use of robot dynamical models, required by most previous studies on 'indirect estimation' of external force, can be practically unfavorable due to inevitable modeling errors as well as arduous identification of system parameters. As a remedy for this problem, the Time-Delay Estimation (TDE) scheme has been incorporated in this research. TDE efficiently provides an accurate estimate of nonlinear robot dynamics including external force. Using TDE, the external force has been effectively and efficiently estimated without F/T sensors or robot dynamical models. Through application to impedance control of a robot, the practical advantages of the proposed estimation algorithm are demonstrated. © 2011 The Korean Society of Mechanical Engineers and Springer-Verlag Berlin Heidelberg.