Influence of the mechanical definition of the functional spinal unit on the musculoskeletal modeling of the cervical spine

2015 ◽  
Vol n° 90 (4) ◽  
pp. 79
Author(s):  
Frédéric Marin
Author(s):  
Nicole A. Kallemeyn ◽  
Srinivas C. Tadepalli ◽  
Kiran H. Shivanna ◽  
Nicole M. Grosland

Preventive measures and treatment modalities for correcting spinal disorders benefit significantly from advancements aimed at understanding the biomechanics of the human spine in the normal as well as altered states [1]. Finite element (FE) modeling is a useful tool to understand the behavior of the cervical spine under such conditions. In order for an FE model to yield clinically relevant results, the geometry must be as realistic as possible [2], in addition to incorporating accurate material properties and boundary conditions. The spine’s anatomy is very complex, rendering it difficult to acquire accurate geometrical representations for FE analysis. Many meshes in the literature are based on simplified or idealized geometries, or are assumed to be symmetric about the sagittal plane [3]. Traditional meshing techniques are time consuming and tedious, and lack remeshing capabilities [2]. The ability to create hexahedral cervical spine FE models on a patient-specific basis is a desirable task because it can account for variations in anatomy, as well as provide insight for surgical planning/treatment. Our mesh development methods improve on existing multi-block meshing methods to make this possible. We have created a C45 functional spinal unit (FSU) using these techniques, and to date have validated it by comparison to data presented in the literature.


Cureus ◽  
2021 ◽  
Author(s):  
Christopher Williams ◽  
Mairin Jerome ◽  
Chaz Fausel ◽  
Ehren Dodson ◽  
Ian Stemper ◽  
...  

2004 ◽  
Vol 9 (2) ◽  
pp. 4-4 ◽  
Author(s):  
Robert H. Haralson

Abstract The AMA Guides to the Evaluation of Permanent Impairment (AMA Guides), Fifth Edition, presents an impairment paradox: Single-level fusions rating using the Diagnosis-related estimates (DRE) method often result in higher impairment values than do multilevel cervical spine fusions. In the AMA Guides, Chapter 15, The Spine, the definition of Cervical Category IV (alteration of motion segment integrity or bilateral or multilevel radiculopathy) changed from the definition in the fourth edition for Cervicothoracic Category IV (loss of motion segment integrity or multilevel neurological compromise) because of changes in the definition of “alteration of motion segment integrity,” which now also includes surgical arthrodesis. This applies only for single-level fusions because the AMA Guides, states the range-of-motion (ROM) method is used in situations when “there is alteration of motion segment integrity (eg, fusions).” The AMA Guides, Fourth Edition, rated impairment on the basis of the injury, not the surgical procedure, and the maximum whole person permanent impairment for a patient with a single-level, single-sided cervical radiculopathy who had a discectomy and fusion would be 15%, but the minimum award for a similar patient rated using the DRE method is 25%. The author reports that, for the reasons outlined, evaluators should rate all cervical fusions, including single-level fusions, using the ROM method.


Spine ◽  
2008 ◽  
Vol 33 (6) ◽  
pp. E178-E182 ◽  
Author(s):  
Yuichiro Morishita ◽  
Shinichi Hida ◽  
Masashi Miyazaki ◽  
Soon-Woo Hong ◽  
Jun Zou ◽  
...  

1966 ◽  
Vol 24 ◽  
pp. 3-5
Author(s):  
W. W. Morgan

1. The definition of “normal” stars in spectral classification changes with time; at the time of the publication of theYerkes Spectral Atlasthe term “normal” was applied to stars whose spectra could be fitted smoothly into a two-dimensional array. Thus, at that time, weak-lined spectra (RR Lyrae and HD 140283) would have been considered peculiar. At the present time we would tend to classify such spectra as “normal”—in a more complicated classification scheme which would have a parameter varying with metallic-line intensity within a specific spectral subdivision.


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