scholarly journals The LP-ESP® lumbar disc prosthesis with 6 degrees of freedom: development and 7 years of clinical experience

2013 ◽  
Vol 23 (2) ◽  
pp. 131-143 ◽  
Author(s):  
Jean-Yves Lazennec ◽  
Alain Aaron ◽  
Adrien Brusson ◽  
Jean-Patrick Rakover ◽  
Marc-Antoine Rousseau
Author(s):  
Samuel Brehm

Abstract The device outlined in this paper is 3D printable cervical disc prosthesis that uses a compliant mechanism to behave biomechanically like a natural cervical intervertebral disc. The device is DMLS printed out of biocompatible titanium as a single part, and can be manufactured to the custom length, width, height, and lordotic angle desired for the patient. The device has 6 degrees of freedom for flexion, extension, and lateral bending. The device has 0.83 mm of max compression with a compressive stiffness of 473.1 N/mm. The device consists of compliant mechanism with two plates fused on the top and bottom. The mechanism is essentially two perpendicular beams fused at their midpoints. The beams act as rotational as well as compressive springs. This allows the rotational and compressive range of motion. This design is intended to minimize the production of wear debris, which is a problem with prosthetics. It also provides the ability for a disc prosthesis to be easily custom manufactured for the patient.


10.5772/53726 ◽  
2013 ◽  
Author(s):  
Jean-Yves Lazennec ◽  
Alain Aaron ◽  
Adrien Brusson ◽  
Jean Patrick ◽  
Marc Antoine

2011 ◽  
Vol 200 (1) ◽  
pp. 47-53 ◽  
Author(s):  
Sabine Scheibe ◽  
Mario M. Dorostkar ◽  
Christian Seebacher ◽  
Rainer Uhl ◽  
Frank Lison ◽  
...  

2015 ◽  
Vol 35 (4) ◽  
pp. 341-347 ◽  
Author(s):  
E. Rouhani ◽  
M. J. Nategh

Purpose – The purpose of this paper is to study the workspace and dexterity of a microhexapod which is a 6-degrees of freedom (DOF) parallel compliant manipulator, and also to investigate its dimensional synthesis to maximize the workspace and the global dexterity index at the same time. Microassembly is so essential in the current industry for manufacturing complicated structures. Most of the micromanipulators suffer from their restricted workspace because of using flexure joints compared to the conventional ones. In addition, the controllability of micromanipulators inside the whole workspace is very vital. Thus, it is very important to select the design parameters in a way that not only maximize the workspace but also its global dexterity index. Design/methodology/approach – Microassembly is so essential in the current industry for manufacturing complicated structures. Most of the micromanipulators suffer from their restricted workspace because of using flexure joints compared to the conventional ones. In addition, the controllability of micromanipulators inside the whole workspace is very vital. Thus, it is very important to select the design parameters in a way that not only maximize the workspace but also its global dexterity index. Findings – It has been shown that the proposed procedure for the workspace calculation can considerably speed the required calculations. The optimization results show that a converged-diverged configuration of pods and an increase in the difference between the moving and the stationary platforms’ radii cause the global dexterity index to increase and the workspace to decrease. Originality/value – The proposed algorithm for the workspace analysis is very important, especially when it is an objective function of an optimization problem based on the search method. In addition, using screw theory can simply construct the homogeneous Jacobian matrix. The proposed methodology can be used for any other micromanipulator.


Soil Research ◽  
2002 ◽  
Vol 40 (8) ◽  
pp. 1399 ◽  
Author(s):  
B. L. Henderson ◽  
E. N. Bui

A new pH water to pH CaCl2 calibration curve was derived from data pooled from 2 National Land and Water Resources Audit projects. A total of 70465 observations with both pH in water and pH in CaCl2 were available for statistical analysis. An additive model for pH in CaCl2 was fitted from a smooth function of pH in water created by a smoothing spline with 6 degrees of freedom. This model appeared stable outside the range of the data and performed well (R2 = 96.2, s = 0.24). The additive model for conversion of pHw to pHCa is sigmoidal over the range of pH 2.5 to 10.5 and is similar in shape to earlier models. Using this new model, a look-up table for converting pHw to pHCa was created.


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