Automatic Generation of Virtual Lumbar Motion Segments for Population-Based Simulation of Lumbar Spine Biomechanics

Author(s):  
Kelli S. Huls ◽  
Anthony J. Petrella

Computational modeling of the spine has become a viable option for evaluating new implants and procedures. Most models described in the literature, however, represent only a single subject and neglect the normal variation that exists among specimens. A probabilistic simulation comprised of virtual specimens representing a broad population of subjects can address this limitation and be used to evaluate implants or procedures pre-clinically. Challenges exist to applying probabilistic modeling techniques to biologic systems, and perhaps the greatest is parameterization of the anatomy to capture normal variation in shape from specimen to specimen. It’s also critical to implement soft tissues in a robust, automated manner that produces representative biomechanics. The purpose of our research is to overcome these challenges and develop a probabilistic framework to perform population-based studies of lumbar spine biomechanics. This paper describes our results to date for the automated generation of virtual lumbar motion segments.

Author(s):  
Kelli S. Barnes ◽  
Jeffrey R. Armstrong ◽  
Amit Agarwala ◽  
Anthony J. Petrella

Finite element modeling of the lumbar spine has advanced significantly in the last decade [1] and become a relatively well established method for examining fundamental biomechanics as well as new spinal implants and procedures. However, most of these models only represent a single subject and do not account for normal subject-to-subject variation. This limitation can be addressed using a probabilistic simulation in which virtual specimens are used to represent a broad population of subjects. The greatest challenge to implementing probabilistic techniques in biomechanical simulation is parameterization of anatomy to capture normal variation across subjects. In the present study, shape variation was captured using a statistical shape model (SSM) and implemented in a probabilistic framework to evaluate biomechanics of a single motion segment. The Monte Carlo (MC) method is a common probabilistic simulation technique that is robust even for non-monotonic or highly non-linear systems. The purpose of this study was to perform a probabilistic study of a lumbar motion segment using MC simulation to determine the sensitivity of spinal rotations to changes in geometry and soft tissue material properties.


Biosensors ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 67
Author(s):  
Song Joo Lee ◽  
Yong-Eun Cho ◽  
Kyung-Hyun Kim ◽  
Deukhee Lee

Knowing the material properties of the musculoskeletal soft tissue could be important to develop rehabilitation therapy and surgical procedures. However, there is a lack of devices and information on the viscoelastic properties of soft tissues around the lumbar spine. The goal of this study was to develop a portable quantifying device for providing strain and stress curves of muscles and ligaments around the lumbar spine at various stretching speeds. Each sample was conditioned and applied for 20 repeatable cyclic 5 mm stretch-and-relax trials in the direction and perpendicular direction of the fiber at 2, 3 and 5 mm/s. Our device successfully provided the stress and strain curve of the samples and our results showed that there were significant effects of speed on the young’s modulus of the samples (p < 0.05). Compared to the expensive commercial device, our lower-cost device provided comparable stress and strain curves of the sample. Based on our device and findings, various sizes of samples can be measured and viscoelastic properties of the soft tissues can be obtained. Our portable device and approach can help to investigate young’s modulus of musculoskeletal soft tissues conveniently, and can be a basis for developing a material testing device in a surgical room or various lab environments.


2021 ◽  
pp. 1-14
Author(s):  
Noura Hamze ◽  
Lukas Nocker ◽  
Nikolaus Rauch ◽  
Markus Walzthöni ◽  
Matthias Harders ◽  
...  

BACKGROUND: Accurate segmentation of connective soft tissues in medical images is very challenging, hampering the generation of geometric models for bio-mechanical computations. Alternatively, one could predict ligament insertion sites and then approximate the shapes, based on anatomical knowledge and morphological studies. OBJECTIVE: In this work, we describe an integrated framework for automatic modelling of human musculoskeletal ligaments. METHOD: We combine statistical shape modelling with geometric algorithms to automatically identify insertion sites, based on which geometric surface/volume meshes are created. As clinical use case, the framework has been applied to generate models of the forearm interosseous membrane. Ligament insertion sites in the statistical model were defined according to anatomical predictions following a published approach. RESULTS: For evaluation we compared the generated sites, as well as the ligament shapes, to data obtained from a cadaveric study, involving five forearms with 15 ligaments. Our framework permitted the creation of models approximating ligaments’ shapes with good fidelity. However, we found that the statistical model trained with the state-of-the-art prediction of the insertion sites was not always reliable. Average mean square errors as well as Hausdorff distances of the meshes could increase by an order of magnitude, as compared to employing known insertion locations of the cadaveric study. Using those, an average mean square error of 0.59 mm and an average Hausdorff distance of less than 7 mm resulted, for all ligaments. CONCLUSIONS: The presented approach for automatic generation of ligament shapes from insertion points appears to be feasible but the detection of the insertion sites with a SSM is too inaccurate, thus making a patient-specific approach necessary.


Spine ◽  
2005 ◽  
Vol 30 (3) ◽  
pp. 346-353 ◽  
Author(s):  
Pierre Roussouly ◽  
Sohrab Gollogly ◽  
Eric Berthonnaud ◽  
Johanes Dimnet

2012 ◽  
Vol 9 (1) ◽  
pp. 249-283 ◽  
Author(s):  
Drazen Brdjanin ◽  
Slavko Maric

This paper presents an approach to the automated design of the initial conceptual database model. The UML activity diagram, as a frequently used business process modeling notation, is used as the starting point for the automated generation of the UML class diagram representing the conceptual database model. Formal rules for automated generation cover the automatic extraction of business objects and business process participants, as well as the automatic generation of corresponding classes and their associations. Based on these rules we have implemented an automatic generator and evaluated it on a real business model.


2014 ◽  
Vol 4 (1_suppl) ◽  
pp. s-0034-1376583-s-0034-1376583
Author(s):  
J. Määttä ◽  
K. M. C. Cheung ◽  
J. Karppinen ◽  
D. Samartzis

2014 ◽  
Vol 14 (5) ◽  
pp. 789-798 ◽  
Author(s):  
Dean K. Stolworthy ◽  
Shannon A. Zirbel ◽  
Larry L. Howell ◽  
Marina Samuels ◽  
Anton E. Bowden

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