TY - JOUR
T1 - Human L3L4 intervertebral disc mean 3D shape, modes of variation, and their relationship to degeneration
AU - Peloquin, John M.
AU - Yoder, Jonathon H.
AU - Jacobs, Nathan T.
AU - Moon, Sung M.
AU - Wright, Alexander C.
AU - Vresilovic, Edward J.
AU - Elliott, Dawn M.
N1 - Funding Information:
Funding was provided by National Institutes of Health grants R01AR050052 and RC1AR058450 .
PY - 2014/7/18
Y1 - 2014/7/18
N2 - Intervertebral disc mechanics are affected by both disc shape and disc degeneration, which in turn each affect the other; disc mechanics additionally have a role in the etiology of disc degeneration. Finite element analysis (FEA) is a favored tool to investigate these relationships, but limited data for intervertebral disc 3D shape has forced the use of simplified or single-subject geometries, with the effect of inter-individual shape variation investigated only in specialized studies. Similarly, most data on disc shape variation with degeneration is based on 2D mid-sagittal images, which incompletely define 3D shape changes. Therefore, the objective of this study was to quantify inter-individual disc shape variation in 3D, classify this variation into independently-occurring modes using a statistical shape model, and identify correlations between disc shape and degeneration. Three-dimensional disc shapes were obtained from MRI of 13 human male cadaver L3L4 discs. An average disc shape and four major modes of shape variation (representing 90% of the variance) were identified. The first mode represented disc axial area and was significantly correlated to degeneration (R2=0.44), indicating larger axial area in degenerate discs. Disc height variation occurred in three distinct modes, each also involving non-height variation. The statistical shape model provides an average L3L4 disc shape for FEA that is fully defined in 3D, and makes it convenient to generate a set of shapes with which to represent aggregate inter-individual variation. Degeneration grade-specific shapes can also be generated. To facilitate application, the model is included in this paper's supplemental content.
AB - Intervertebral disc mechanics are affected by both disc shape and disc degeneration, which in turn each affect the other; disc mechanics additionally have a role in the etiology of disc degeneration. Finite element analysis (FEA) is a favored tool to investigate these relationships, but limited data for intervertebral disc 3D shape has forced the use of simplified or single-subject geometries, with the effect of inter-individual shape variation investigated only in specialized studies. Similarly, most data on disc shape variation with degeneration is based on 2D mid-sagittal images, which incompletely define 3D shape changes. Therefore, the objective of this study was to quantify inter-individual disc shape variation in 3D, classify this variation into independently-occurring modes using a statistical shape model, and identify correlations between disc shape and degeneration. Three-dimensional disc shapes were obtained from MRI of 13 human male cadaver L3L4 discs. An average disc shape and four major modes of shape variation (representing 90% of the variance) were identified. The first mode represented disc axial area and was significantly correlated to degeneration (R2=0.44), indicating larger axial area in degenerate discs. Disc height variation occurred in three distinct modes, each also involving non-height variation. The statistical shape model provides an average L3L4 disc shape for FEA that is fully defined in 3D, and makes it convenient to generate a set of shapes with which to represent aggregate inter-individual variation. Degeneration grade-specific shapes can also be generated. To facilitate application, the model is included in this paper's supplemental content.
UR - http://www.scopus.com/inward/record.url?scp=84902094638&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=84902094638&partnerID=8YFLogxK
U2 - 10.1016/j.jbiomech.2014.04.014
DO - 10.1016/j.jbiomech.2014.04.014
M3 - Article
C2 - 24792581
AN - SCOPUS:84902094638
SN - 0021-9290
VL - 47
SP - 2452
EP - 2459
JO - Journal of Biomechanics
JF - Journal of Biomechanics
IS - 10
ER -