A viscoelastic artificial disc may more closely replicate normal stiffness characteristics of the healthy human disc compared with first-generation total disc replacement (TDR) devices, which do not utilize viscoelastic materials and are based on a ball and socket design that does not allow loading compliance. Mechanical testing was performed to characterize the durability and range of motion (ROM) of an investigational viscoelastic TDR (VTDR) device for the lumbar spine, the Freedom® Lumbar Disc. ROM data were compared with data reported for the human lumbar disc in the clinical literature. Flexibility and stiffness of the VTDR in compression, rotation, and flexion/extension were within the parameters associated with the normal human lumbar disc. The device constrained motion to physiologic ranges and replicated normal stress/strain dynamics. No mechanical or functional failures occurred within the loads and ROM experienced by the human disc. Fatigue testing of the worst case VTDR device size demonstrated a fatigue life of 50 years of simulated walking and 240 years of simulated significant bends in both flexion/extension and lateral bending coupled with axial rotation, with no functional failures. These results indicate that the VTDR evaluated in this mechanical study is durable and has the ability to replicate the stiffness and mechanics of the natural, healthy human lumbar disc.

1.
Merrill
,
C.
, and
Elixhauser
,
A.
, 2007, “
Hospital Stays Involving Musculoskeletal Procedures, 1997–2005
,” HCUP Statistical Brief No. 34, Agency for Healthcare Research and Quality, Rockville, MD, available at http://www.hcup-us.ahrq.gov/reports/statbriefs/sb34.pdfhttp://www.hcup-us.ahrq.gov/reports/statbriefs/sb34.pdf, accessed Aug. 9, 2010.
2.
Turner
,
J. A.
,
Ersek
,
M.
,
Herron
,
L.
,
Haselkorn
,
J.
,
Kent
,
D.
,
Ciol
,
M. A.
, and
Deyo
,
R.
, 1992, “
Patient Outcomes After Lumbar Spinal Fusions
,”
JAMA, J. Am. Med. Assoc.
0098-7484,
268
(
7
), pp.
907
911
.
3.
Boos
,
N.
, and
Webb
,
J. K.
, 1997, “
Pedicle Screw Fixation in Spinal Disorders: A European View
,”
Eur. Spine J.
0940-6719,
6
(
1
), pp.
2
18
.
4.
Bono
,
C. M.
, and
Lee
,
C. K.
, 2004, “
Critical Analysis of Trends in Fusion for Degenerative Disc Disease Over the Past 20 Years: Influence of Technique on Fusion Rate and Clinical Outcome
,”
Spine
0362-2436,
29
(
4
), pp.
455
463
.
5.
Christensen
,
F. B.
, 2004, “
Lumbar Spinal Fusion. Outcome in Relation to Surgical Methods, Choice of Implant and Postoperative Rehabilitation
,”
Acta Orthop. Scand. Suppl.
0300-8827,
75
(
313
), pp.
2
43
.
6.
Spine Interbody Research Group
,
Sasso
,
R. C.
,
LeHuec
,
J. C.
, and
Shaffrey
,
C.
, 2005, “
Iliac Crest Bone Graft Donor Site Pain After Anterior Lumbar Interbody Fusion: A Prospective Patient Satisfaction Outcome Assessment
,”
J. Spinal Disord. Tech.
,
18
, pp.
S77
S81
.
7.
Park
,
P.
,
Garton
,
H. J.
,
Gala
,
V. C.
,
Hoff
,
J. T.
, and
McGillicuddy
,
J. E.
, 2004, “
Adjacent Segment Disease After Lumbar or Lumbosacral Fusion: Review of the Literature
,”
Spine
0362-2436,
29
(
17
), pp.
1938
1944
.
8.
Harrop
,
J. S.
,
Youssef
,
J. A.
,
Maltenfort
,
M.
,
Vorwald
,
P.
,
Jabbour
,
P.
,
Bono
,
C. M.
,
Goldfarb
,
N.
,
Vaccaro
,
A. R.
, and
Hilibrand
,
A. S.
, 2008, “
Lumbar Adjacent Segment Degeneration and Disease After Arthrodesis and Total Disc Arthroplasty
,”
Spine
0362-2436,
33
(
15
), pp.
1701
1707
.
9.
Rahm
,
M. D.
, and
Hall
,
B. B.
, 1996, “
Adjacent-Segment Degeneration After Lumbar Fusion With Instrumentation: A Retrospective Study
,”
J. Spinal Disord.
0895-0385,
9
(
5
), pp.
392
400
.
10.
Huang
,
R. C.
,
Girardi
,
F. P.
,
Cammisa
,
F. P.
, Jr.
,
Lim
,
M. R.
,
Tropiano
,
P.
, and
Murnay
,
T.
, 2005, “
Correlation Between Range of Motion and Outcome After Lumbar Total Disc Replacement: 8.6-Year Follow-Up
,”
Spine
0362-2436,
30
, pp.
1407
1411
.
11.
Chung
,
S. S.
,
Lee
,
C. S.
, and
Kang
,
C. S.
, 2006, “
Lumbar Total Disc Replacement Using ProDisc II: A Prospective Study With a 2-Year Minimum Follow-Up
,”
J. Spinal Disord. Tech.
,
19
(
6
), pp.
411
415
.
12.
Huang
,
R. C.
,
Tropiano
,
P.
,
Marnay
,
T.
,
Girardi
,
F. P.
,
Lim
,
M. R.
, and
Cammisa
,
F. P.
, Jr.
, 2006, “
Range of Motion and Adjacent Level Degeneration After Lumbar Total Disc Replacement
,”
Spine J.
,
6
(
3
), pp.
242
247
.
13.
Putzier
,
M.
,
Funk
,
J. F.
,
Schneider
,
S. V.
,
Gross
,
C.
,
Tohtz
,
S. W.
,
Khodadadyan-Klostermann
,
C.
,
Perka
,
C.
, and
Kandziora
,
F.
, 2006, “
Charite Total Disc Replacement—Clinical and Radiographical Results After an Average Follow-Up of 17 Years
,”
Eur. Spine J.
0940-6719,
15
(
2
), pp.
183
195
.
14.
Huang
,
R. C.
,
Girardi
,
F. P.
,
Cammisa
,
F. P.
, Jr.
, and
Wright
,
T. M.
, 2003, “
The Implications of Constraint in Lumbar Total Disc Replacement
,”
J. Spinal Disord. Tech.
,
16
(
4
), pp.
412
417
.
15.
Blumenthal
,
S.
,
McAfee
,
P. C.
,
Guyer
,
R. D.
,
Hochschuler
,
S. H.
,
Geisler
,
F. H.
,
Holt
,
R. T.
,
Garcia
,
R.
, Jr.
,
Regan
,
J. J.
, and
Ohnmeiss
,
D. D.
, 2005, “
A Prospective, Randomized, Multicenter Food and Drug Administration Investigational Device Exemptions Study of Lumbar Total Disc Replacement With the CHARITE Artificial Disc Versus Lumbar Fusion: Part I: Evaluation of Clinical Outcomes
,”
Spine
0362-2436,
30
(
14
), pp.
1565
1575
.
16.
Lemaire
,
J. -P.
,
Carrier
,
H.
,
Ali
,
E. -H. S.
,
Skalli
,
W.
, and
Lavaste
,
F.
, 2005, “
Clinical and Radiological Outcomes With the CharitéTM Artificial Disc: A 10-Year Minimum Follow-Up
,”
J. Spinal Disord. Tech.
,
18
(
4
), pp.
353
359
.
17.
Freeman
,
B. J. C.
, and
Davenport
,
J.
, 2006, “
Total Disc Replacement in the Lumbar Spine: A Systematic Review of the Literature
,”
Eur. Spine J.
0940-6719,
15
, pp.
439
447
.
18.
Krishnaney
,
A. A.
,
Park
,
J.
, and
Benzel
,
E. C.
, 2007, “
Surgical Management of Neck and Low Back Pain
,”
Neurol. Clin.
0733-8619,
25
(
2
), pp.
507
522
.
19.
Iatridis
,
J. C.
,
Weidenbaum
,
M.
,
Setton
,
L. A.
, and
Mow
,
V. C.
, 1996, “
Is the Nucleus Pulposus a Solid or a Fluid? Mechanical Behaviors of the Nucleus Pulposus of the Human Intervertebral Disc
,”
Spine
0362-2436,
21
(
10
), pp.
1174
1184
.
20.
Iatridis
,
J. C.
,
Setton
,
L. A.
,
Weidenbaum
,
M.
, and
Mow
,
V. C.
, 1997, “
The Viscoelastic Behavior of the Non-Degenerate Human Lumbar Nucleus Pulposus in Shear
,”
J. Biomech.
0021-9290,
30
(
10
), pp.
1005
1013
.
21.
ASTM Standard F2423, 2005, “
Standard Guide for Functional, Kinematic, and Wear Assessment of Total Disc Prostheses
,” ASTM International, West Conshohocken, PA.
22.
ASTM Standard F2346, 2005, “
Standard Test Methods for Static and Dynamic Characterization of Spinal Artificial Discs
,” ASTM International, West Conshohocken, PA.
23.
Berkson
,
M. H.
,
Nachemson
,
A.
, and
Schultz
,
A. B.
, 1979, “
Mechanical Properties of Human Lumbar Spine Motion Segments—Part II: Responses in Compression and Shear; Influence of Gross Morphology
,”
ASME J. Biomech. Eng.
0148-0731,
101
, pp.
53
75
.
24.
Tencer
,
A. F.
,
Ahmed
,
A. M.
, and
Burke
,
D. L.
, 1982, “
Some Static Mechanical Properties of the Lumbar Intervertebral Joint, Intact and Injured
,”
ASME J. Biomech. Eng.
0148-0731,
104
(
3
), pp.
193
201
.
25.
White
,
A. A.
, III
, and
Panjabi
,
M. M.
, 1990,
Clinical Biomechanics of the Spine
,
2nd ed.
,
Lippincott Williams & Wilkins
,
Philadelphia, PA
, pp.
9
and
107
.
26.
Eijkelkamp
,
M. F.
,
van Donkelaar
,
C. C.
,
van Horn
,
J. R.
,
Huyghe
,
J. M.
, and
Verkerke
,
G. J.
, 2001, “
Requirements for an Artificial Intervertebral Disc
,”
Int. J. Artif. Organs
0391-3988,
24
(
5
), pp.
311
321
.
27.
Li
,
S.
,
Patwardhan
,
A. G.
,
Amirouche
,
F. M.
,
Havey
,
R.
, and
Meade
,
K. P.
, 1995, “
Limitations of the Standard Linear Solid Model of Intervertebral Discs Subject to Prolonged Loading and Low-Frequency Vibration in Axial Compression
,”
J. Biomech.
0021-9290,
28
(
7
), pp.
779
790
.
28.
Kimura
,
S.
,
Steinbach
,
G. C.
,
Watenpaugh
,
D. E.
, and
Hargens
,
A. R.
, 2001, “
Lumbar Spine Disc Height and Curvature Responses to an Axial Load Generated by a Compression Device Compatible With Magnetic Resonance Imaging
,”
Spine
0362-2436,
26
(
23
), pp.
2596
2600
.
29.
Schultz
,
A. B.
,
Warwick
,
D. N.
,
Berkson
,
M. H.
, and
Nachemson
,
A. L.
, 1979, “
Mechanical Properties of Human Lumbar Spine Motion Segments—Part I: Responses in Flexion, Extension, Lateral Bending, and Torsion
,”
ASME J. Biomech. Eng.
0148-0731,
101
, pp.
46
52
.
30.
Pearcy
,
M.
,
Portek
,
I.
, and
Shepherd
,
J.
, 1984, “
Three-Dimensional X-Ray Analysis of Normal Movement in the Lumbar Spine
,”
Spine
0362-2436,
9
(
3
), pp.
294
297
.
31.
Panjabi
,
M.
,
Henderson
,
G.
,
Abjornson
,
C.
, and
Yue
,
J.
, 2007, “
Multidirectional Testing of One- and Two-Level ProDisc-L Versus Simulated Fusions
,”
Spine
0362-2436,
32
(
12
), pp.
1311
1319
.
32.
Panjabi
,
M.
,
Malcolmson
,
G.
,
Teng
,
E.
,
Tominaga
,
Y.
,
Henderson
,
G.
, and
Serhan
,
H.
, 2007, “
Hybrid Testing of Lumbar CHARITÉ Discs Versus Fusions
,”
Spine
0362-2436,
32
(
9
), pp.
959
966
.
33.
Phillips
,
F. M.
,
Cunningham
,
B.
,
Carandang
,
G.
,
Ghanayem
,
A. J.
,
Voronov
,
L.
,
Havey
,
R. M.
, and
Patwardhan
,
A. G.
, 2004, “
Effect of Supplemental Translaminar Facet Screw Fixation on the Stability of Stand-Alone Anterior Lumbar Interbody Fusion Cages Under Physiologic Compressive Preloads
,”
Spine
0362-2436,
29
(
16
), pp.
1731
1736
.
34.
McAfee
,
P. C.
,
Cunningham
,
B.
,
Holsapple
,
G.
,
Adams
,
K.
,
Blumenthal
,
S.
,
Guyer
,
R. D.
,
Dmietriev
,
A.
,
Maxwell
,
J. H.
,
Regan
,
J. J.
, and
Isaza
,
J.
, 2005, “
A Prospective, Randomized, Multicenter Food and Drug Administration Investigational Device Exemption Study of Lumbar Total Disc Replacement With the CHARITÉ Artificial Disc Versus Lumbar Fusion: Part II: Evaluation of Radiographic Outcomes and Correlation of Surgical Technique Accuracy With Clinical Outcomes
,”
Spine
0362-2436,
30
(
14
), pp.
1576
1583
.
35.
David
,
T.
, 2007, “
Long-Term Results of One-Level Lumbar Arthroplasty: Minimum 10-Year Follow-Up of the CHARITÉ Artificial Disc in 106 Patients
,”
Spine
0362-2436,
32
(
6
), pp.
661
666
.
36.
Zigler
,
J.
,
Delamarter
,
R.
,
Spivak
,
J. M.
,
Linovitz
,
R. J.
,
Danielson
,
G. O.
, III
,
Haider
,
T. T.
,
Cammisa
,
F.
,
Zuchermann
,
J.
,
Balderston
,
R.
,
Kitchel
,
S.
,
Foley
,
K.
,
Watkins
,
R.
,
Bradford
,
D.
,
Yue
,
J.
,
Yuan
,
H.
,
Herkowitz
,
H.
,
Geiger
,
D.
,
Bendo
,
J.
,
Peppers
,
T.
,
Sachs
,
B.
,
Girardi
,
F.
,
Kropf
,
M.
, and
Goldstein
,
J.
, 2007, “
Results of the Prospective, Randomized, Multicenter Food and Drug Administration Investigational Device Exemption Study of the ProDisc-L Total Disc Replacement Versus Circumferential Fusion for the Treatment of 1-Level Degenerative Disc Disease
,”
Spine
0362-2436,
32
(
11
), pp.
1155
1162
.
37.
Guyer
,
R. D.
,
McAfee
,
P. C.
,
Banco
,
R. J.
,
Bitan
,
F. D.
,
Cappuccino
,
A.
,
Geisler
,
F. H.
,
Hochschuler
,
S. H.
,
Holt
,
R. T.
,
Jenis
,
L. G.
,
Majd
,
M. E.
,
Regan
,
J. J.
,
Tromansauser
,
S. G.
,
Wong
,
D. C.
, and
Blumenthal
,
S. L.
, 2009, “
Prospective, Randomized, Multicenter Food and Drug Administration Investigational Device Exemption Study of Lumbar Total Disc Replacement With the CHARITE Artificial Disc Versus Lumbar Fusion: Five-Year Follow-Up
,”
Spine J.
,
9
(
5
), pp.
374
386
.
38.
Nachemson
,
A. L.
, 1981, “
Disc Pressure Measurements
,”
Spine
0362-2436,
6
(
1
), pp.
93
97
.
39.
Han
,
J. S.
,
Goel
,
V. K.
,
Ahn
,
J. Y.
,
Winterbottom
,
J.
,
McGowan
,
D.
,
Weinstein
,
J.
, and
Cook
,
T.
, 1995, “
Loads in the Spinal Structures During Lifting: Development of a Three-Dimensional Comprehensive Biomechanical Model
,”
Eur. Spine J.
0940-6719,
4
(
3
), pp.
153
168
.
40.
Hedman
,
T. P.
,
Kostuik
,
J. P.
,
Fernie
,
G. R.
, and
Heller
,
W. G.
, 1991, “
Design of an Intervertebral Disc Prosthesis
,”
Spine
0362-2436,
16
(
6
), pp.
S256
S260
.
41.
Schmalzried
,
T. P.
,
Szuszczewicz
,
E. S.
,
Northfield
,
M. R.
,
Akizuki
,
K. H.
,
Frankel
,
R. E.
,
Belcher
,
G.
, and
Amstutz
,
H. C.
, 1998, “
Quantitative Assessment of Walking Activity After Total Hip or Knee Replacement
,”
J. Bone Jt. Surg., Am. Vol.
0021-9355,
80
(
1
), pp.
54
59
.
42.
Morlock
,
M.
,
Schneider
,
E.
,
Bluhm
,
A.
,
Vollmer
,
M.
,
Bergmann
,
G.
,
Muller
,
V.
, and
Honl
,
M.
, 2001, “
Duration and Frequency of Every Day Activities in Total Hip Patients
,”
J. Biomech.
0021-9290,
34
(
7
), pp.
873
881
.
43.
U.S. Food and Drug Administration
, 2004, “
Summary of Safety and Effectiveness Data: CHARITÉ Artifical Disc
,” available at http://www.accessdata.fda.gov/cdrh_docs/pdf4/P040006b.pdfhttp://www.accessdata.fda.gov/cdrh_docs/pdf4/P040006b.pdf, accessed May 25, 2010.
44.
U.S. Food and Drug Administration
, 2006, “
Summary of Safety and Effectiveness Data: PRODISC®-L Total Disc Replacement
,” available at http://www.accessdata.fda.gov/cdrh_docs/pdf5/P050010b.pdfhttp://www.accessdata.fda.gov/cdrh_docs/pdf5/P050010b.pdf, accessed May 25, 2010.
45.
Jacobs
,
J. J.
,
Hallab
,
N. J.
,
Urban
,
R. M.
, and
Wimmer
,
M. A.
, 2006, “
Wear Particles
,”
J. Bone Jt. Surg., Am. Vol.
0021-9355,
88
, pp.
99
102
.
46.
Harper
,
M. L.
,
Dooris
,
A.
, and
Paré
,
P. E.
, 2009, “
The Fundamentals of Biotribology and Its Application to Spine Arthroplasty
,”
SAS J.
,
3
(
4
), pp.
125
132
.
47.
van Ooij
,
A.
,
Oner
,
F. C.
, and
Verbout
,
A. J.
, 2003, “
Complications of Artificial Disc Replacement: A Report of 27 Patients With the SB Charité Disc
,”
J. Spinal Disord. Tech.
,
16
(
4
), pp.
369
383
.
48.
Phillips
,
F.
,
Diaz
,
R.
, and
Pimenta
,
L.
, 2005, “
The Fate of the Facet Joints After Lumbar Total Disc Replacement: A Clinical and MRI Study
,”
Spine J.
,
5
(
4
), p.
S75
.
49.
Lemaire
,
J. P.
,
Skalli
,
W.
,
Lavaste
,
F.
,
Templier
,
A.
,
Mendes
,
F.
,
Diop
,
A.
,
Sauty
,
V.
, and
Laloux
,
E.
, 1997, “
Intervertebral Disc Prosthesis. Results and Prospects for the Year 2000
,”
Clin. Orthop. Relat. Res.
0009-921X,
337
, pp.
64
76
.
50.
Shim
,
C. S.
,
Lee
,
S. H.
,
Shin
,
H. D.
,
Kang
,
H. S.
,
Choi
,
W. C.
,
Jung
,
B.
,
Choi
,
G.
,
Ahn
,
Y.
,
Lee
,
S.
, and
Lee
,
H. Y.
, 2007, “
Charité Versus ProDisc: A Comparative Study of a Minimum 3-Year Follow-Up
,”
Spine
0362-2436,
32
(
9
), pp.
1012
1018
.
51.
Park
,
C. K.
,
Ryu
,
K. S.
, and
Jee
,
W. H.
, 2008, “
Degenerative Changes of Discs and Facet Joints in Lumbar Total Disc Replacement Using ProDisc II: Minimum Two-Year Follow-Up
,”
Spine
0362-2436,
33
(
16
), pp.
1755
1761
.
52.
de Kleuver
,
M.
,
Oner
,
F. C.
, and
Jacobs
,
W. C.
, 2003, “
Total Disc Replacement for Chronic Low Back Pain: Background and a Systematic Review of the Literature
,”
Eur. Spine J.
0940-6719,
12
(
2
), pp.
108
116
.
53.
Link
,
H. D.
, 2002, “
History, Design and Biomechanics of the LINK SB Charité Artificial Disc
,”
Eur. Spine J.
0940-6719,
11
, pp.
S98
S105
.
You do not currently have access to this content.