We hypothesize that a direction-dependent flow resistance exists in the intervertebral disc due to constriction flow in the cartilage endplates. A comparison of the hydrostatic pressure in the nucleus of the healthy intervertebral disc during daily loading with the relatively low osmotic swelling pressure during rest, suggests the necessity of such directiondependent flow resistance to ensure that all the fluid exuded from the disc during loading is recovered during rest. A physical model demonstrating the direction-dependent resistance of constriction flow in a poroelastic solid is presented. A finite element model was developed and validated against this physical model. The finite element model showed that decrease of the constriction hole area not only increases the resistance to fluid flow, but also causes the direction-dependency of flow resistance to decrease. Through this mechanism, endplate sclerosis could affect normal daily fluid exchange in the intervertebral disc, resulting in decreased mass transport and/or dehydration of the disc. [S0148-0731(00)00406-4]

Issue Section:
Technical Papers
Keywords:
Intervertebral Disc, Endplate, Cartilage, Poroelastic, Fluid Flow, Biomechanics, Finite Element Analysis, biological fluid dynamics, osmosis, swelling, biocontrol, physiological models, finite element analysis, mass transfer, porosity, flow through porous media, orthopaedics
Topics:
Cartilage, Finite element analysis, Finite element model, Flow (Dynamics), Fluids, Intervertebral discs, Pressure, Valves, Disks, Permeability, Fluid dynamics
1.
Adams
,
M. A.
,
McNally
,
D. S.
, and
Dolan
,
P.
,
1996
, “
‘Stress’ Distributions Inside Intervertebral Discs: The Effects of Age and Degeneration
,”
J. Bone Joint Surg. Br.
,
78
, pp.
965
–
972
.
2.
McNally
,
D. S.
, and
Adams
,
M.
,
1992
, “
Internal Intervertebral Disc Mechanics as Revealed by Stress Profilometry
,”
Spine
,
17
, pp.
66
–
73
.
3.
Urban
,
J. P. G.
, and
McMullin
,
J. F.
,
1988
, “
Swelling Pressure of the Lumbar Intervertebral Discs: Influence of Age, Spinal Level, Composition and Degeneration
,”
Spine
,
13
, pp.
179
–
187
.
4.
Nachemson
,
A.
, and
Elfstroem
,
G.
,
1970
, “
Intravital Dynamic Pressure Measurements in Lumbar Discs
,”
Scand. J. Rehabil. Med.
,
S1
, pp.
5
–
40
.
5.
Wilke
,
H. J.
,
Neef
,
P.
,
Caimi
,
M.
,
Hoogland
,
T.
, and
Claes
,
L. E.
,
1999
, “
New in Vivo Measurements of Pressures in the Intervertebral Disc in Daily Life
,”
Spine
,
24
, pp.
755
–
762
.
6.
Urban
,
J. P. G.
,
1987
, “
Factors Influencing the Fluid Content of Intervertebral Discs
,”
Adv. Microcirc.
,
13
, pp.
160
–
170
.
7.
Ayotte
,
D.
,
Tepic
,
S.
, and
Ito
,
K.
,
1999
, “
Fluid Flow in the Intervertebral Disc and Its Relation to Disc Degeneration
,”
J. Bone Joint Surg. Br.
,
81
, p.
67
67
.
8.
Setton
,
L. A.
,
Zhu
,
W.
,
Weinbaum
,
M.
,
Ratcliff
,
A.
, and
Mow
,
V. C.
,
1993
, “
Compressive Properties of the Cartilaginous End-Plate of the Baboon Lumbar Spine.
”
J. Orthop. Res.
,
11
, pp.
228
–
239
.
9.
Mow
,
V. C.
,
Kuei
,
S. C.
,
Lai
,
W. M.
, and
Armstrong
,
C. G.
,
1980
, “
Biphasic Creep and Stress Relaxation of Articular Cartilage in Compression: Theory and Experiments
,”
ASME J. Biomech. Eng.
,
102
, pp.
73
–
84
.
10.
Bernick
,
S.
, and
Cailliet
,
R.
,
1982
, “
Vertebral End-Plate Changes With Aging of Human Vertebrae
,”
Spine
,
7
, pp.
97
–
102
.
11.
Roberts
,
S.
,
Menage
,
J.
, and
Eisenstein
,
S. M.
,
1993
, “
The Cartilage End-Plate and Intervertebral Disc in Scoliosis: Calcification and Other Sequelae
,”
J. Orthop. Res.
,
5
, pp.
747
–
757
.
12.
Nachemson
,
A.
,
Lewin
,
T.
,
Maroudas
,
A.
, and
Freeman
,
M. A. R.
,
1970
, “
In Vitro Diffusion of Dye Through the End-Plates and the Annulus Fibrosus of Human Lumbar Inter-Vertebral Discs
,”
Acta Orthop. Scand.
,
41
, pp.
589
–
607
.
13.
Gibson, L. J., and Ashby, M. F., 1988, Cellular Solids: Structure and Properties, Pergamon Press, New York.
14.
Happel, J., and Brenner, H., 1983, Low Reynolds Number Hydrodynamics, Martinus Nijhoff, Den Hague.
15.
Buschmann
,
M.
,
Soulha
,
J.
,
Shirazi-Adl
,
A.
,
Jurvelin
,
J. S.
, and
Hunziker
,
E. B.
,
1998
, “
Confined Compression of Articular Cartilage: Linearity in Ramp and Sinusoidal Tests and the Importance of Interdigitation and Incomplete Confinement
,”
J. Biomech.
,
31
, pp.
171
–
178
.
16.
Ayotte, D., Tepic, S., and Ito, K., 2000, “Direction-Dependent Resistance to Flow in the Endplate of the Intervertebral Disc: An Ex Vivo Study,” J. Orthop. Res., submitted.
17.
Cassidy
,
J. J.
,
Hiltner
,
A.
, and
Baer
,
E.
,
1990
, “
The Response of the Hierarchical Structure of the Intervertebral Disc to Uniaxial Compression
,”
J. Mat. Med.
,
1
, pp.
69
–
80
.
18.
Maroudas
,
A.
,
Stockwell
,
R.
,
Nachemson
,
A.
, and
Urban
,
J.
,
1975
, “
Factors Involved in the Nutrition of the Human Lumbar Intervertebral Disc: Cellularity and Diffusion of Glucose in Vitro
,”
J. Anat.
,
120
, pp.
113
–
130
.
19.
Urban
,
J. P. G.
,
Holm
,
S.
,
Maroudas
,
A.
, and
Nachemson
,
A.
,
1977
, “
Nutrition of the Intervertebral Disc, An in Vivo Study of Solute Transport
,”
Clin. Orthop.
,
129
, pp.
101
–
114
.
20.
Urban
,
J.
,
Holm
,
S.
, and
Maroudas
,
A.
,
1978
, “
Diffusion of Small Solutes Into the Intervertebral Disc: An in Vivo Study
,”
Biorheology
,
15
, pp.
203
–
223
.
21.
Ogata
,
K.
, and
Whiteside
,
L. A.
,
1981
, “
Nutritional Pathways of the Intervertebral Disc, An Experimental Study Using Hydrogen Washout Technique
,”
Spine
,
6
, pp.
211
–
216
.
22.
Maroudas, A., 1980, “Physical Chemistry of Articular Cartilage and the Intervertebral Disc,” The Joints and Synovial Fluid, Sokoloff, L., ed., Academic Press, New York, pp. 240–293.
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