Currently, rigid fixation systems are the gold standard for degenerative disk disease treatment. Dynamic fixation systems have been proposed as alternatives for the treatment of a variety of spinal disorders. These systems address the main drawbacks of traditional rigid fixation systems, such as adjacent segment degeneration and instrumentation failure. Pedicle-screw-based dynamic stabilization (PDS) is one type of these alternative systems. The aim of this study was to simulate the biomechanical effect of a novel posterior dynamic stabilization system, which is comprised of dynamic (hinged) screws interconnected with a coiled, spring-based dynamic rod (DSDR), and compare it to semirigid (DSRR and RSRR) and rigid stabilization (RSRR) systems. A validated finite element (FE) model of L1-S1 was used to quantify the biomechanical parameters of the spine, such as range of motion, intradiskal pressure, stresses and facet loads after single-level instrumentation with different posterior stabilization systems. The results obtained from in vitro experimental intact and instrumented spines were used to validate the FE model, and the validated model was then used to compare the biomechanical effects of different fixation and stabilization constructs with intact under a hybrid loading protocol. The segmental motion at L4–L5 increased by 9.5% and 16.3% in flexion and left rotation, respectively, in DSDR with respect to the intact spine, whereas it was reduced by 6.4% and 10.9% in extension and left-bending loads, respectively. After instrumentation-induced intradiskal pressure at adjacent segments, L3-L4 and L5-S1 became less than the intact in dynamic rod constructs (DSDR and RSDR) except in the RSDR model in extension where the motion was higher than intact by 9.7% at L3-L4 and 11.3% at L5-S1. The facet loads were insignificant, not exceeding 12N in any of the instrumented cases in flexion. In extension, the facet load in DSDR case was similar to that in intact spine. The dynamic rod constructions (DSDR and RSDR) led to a lesser peak stress at screws compared with rigid rod constructions (DSRR and RSRR) in all loading cases. A dynamic construct consisting of a dynamic rod and a dynamic screw did protect the adjacent level from excessive motion.

References

1.
Cho
,
B. Y.
,
Murovic
,
J.
,
Park
,
K. W.
, and
Park
,
J.
,
2010
, “
Lumbar Disc Rehydration Postimplantation of a Posterior Dynamic Stabilization System
,”
J. Neurosurg. Spine
,
13
(
5
), pp.
576
80
.10.3171/2010.5.SPINE08418
2.
Sengupta
,
D. K.
,
2004
, “
Dynamic Stabilization Devices in the Treatment of Low Back Pain
,”
Orthop. Clin. North Am.
,
35
(
1
), pp.
43
56
.10.1016/S0030-5898(03)00087-7
3.
Mageswaran
,
P.
,
Techy
,
F.
,
Colbrunn
,
R. W.
,
Bonner
,
T. F.
, and
McLain
,
R. F.
,
2012
, “
Hybrid Dynamic Stabilization: A Biomechanical Assessment of Adjacent and Supraadjacent Levels of the Lumbar Spine
,”
J. Neuorsurg. Spine
,
17
, pp.
232
242
.10.3171/2012.6.SPINE111054
4.
Schmoelz
,
W.
,
Huber
,
J. F.
,
Nydegger
,
T.
,
Dipl–Ing, Claes
,
L.
, and
Wilke
,
H. J.
,
2003
, “
Dynamic Stabilization of the Lumbar Spine and Its Effects on Adjacent Segments: An in vitro Experiment
,”
J. Spinal Disord. Tech.
,
16
(
4
), pp.
418
423
.10.1097/00024720-200308000-00015
5.
Ianuzzi
,
A.
,
Kurtz
,
S. M.
,
Kane
,
W.
,
Shah
,
P.
,
Siskey
,
R.
,
van Ooij
,
A.
,
Bindal
,
R.
,
Ross
,
R.
,
Lanman
,
T.
,
Büttner-Janz
,
K.
, and
Isaza
,
J.
,
2010
, “
In Vivo Deformation, Surface Damage, and Biostability of Retrieved Dynesys Systems
,”
Spine
,
35
(
23
), pp.
E1310
E1316
.10.1097/BRS.0b013e3181d6f84f
6.
Goel
, V
. K.
,
Konz
,
R. J.
,
Chang
,
H. T.
,
Grosland
,
N. M.
,
Grobler
,
L. J.
, and
Chesmel
,
K. D.
,
2001
, “
Hinged-Dynamic Posterior Device Permits Greater Loads on the Graft and Similar Stability as Compared With Its Equivalent Rigid Device: A Three-Dimensional Finite Element Assessment
,”
J. Prosthet. Orthot.
,
13
(
1
), pp.
17
20
.10.1097/00008526-200103000-00013
7.
Sengupta
,
D. K.
, and
Herkowitz
,
H. N.
,
2012
, “
Pedicle Screw-Based Posterior Dynamic Stabilization: Literature Review
,”
Adv. Orthop.
,
2012
, p. 424268.10.1155/2012/424268
8.
Jahng
,
T.-A.
,
Kim
,
Y. E.
, and
Moon
,
K. Y.
,
2013
, “
Comparison of the Biomechanical Effect of Pedicle-Based Dynamic Stabilization: A Study Using Finite Element Analysis
,”
Spine J.
,
13
(
1
), pp.
85
94
.10.1016/j.spinee.2012.11.014
9.
Dooris
,
A. P.
,
Goel
,
V. K.
,
Grosland
,
N. M.
,
Gilbertson
,
L. G.
, and
Wilder
,
D. G.
,
2001
, “
Load-Sharing Between Anterior and Posterior Elements in a Lumbar Motion Segment Implanted With an Artificial Disc
,”
Spine
,
26
(
6
), pp.
E122
E129
.10.1097/00007632-200103150-00004
10.
Goel
, V
. K.
,
Grauer
,
J. N.
,
Patel
,
T. C.
,
Biyani
,
A.
,
Sairyo
,
K.
,
Vishnubhotla
,
S.
,
Matyas
,
A.
,
Cowgill
, I
.
,
Shaw
,
M.
,
Long
,
R.
,
Dick
,
D.
,
Panjabi
,
M. M.
, and
Serhan
,
H.
,
2005
, “
Effects of Charité Artificial Disc on the Implanted and Adjacent Spinal Segments Mechanics Using a Hybrid Testing Protocol
,”
Spine
,
30
(
24
), pp.
2755
2764
.10.1097/01.brs.0000195897.17277.67
11.
Grauer
,
J. N.
,
Biyani
,
A.
,
Faizan
,
A.
,
Kiapour
,
A.
,
Sairyo
,
K.
,
Ivanov
,
A.
,
Ebraheim
,
N. A.
,
Patel
,
T. C.
, and
Goel
,
V. K.
,
2006
, “
Biomechanics of Two-Level Charité Artificial Disc Placement in Comparison to Fusion Plus Single-Level Disc Placement Combination
,”
Spine J.
,
6
(
6
), pp.
659
666
.10.1016/j.spinee.2006.03.011
12.
Ivanov
,
A. A.
,
Kiapour
,
A.
,
Ebraheim
,
N. A.
, and
Goel
, V
.
,
2009
, “
Lumbar Fusion Leads to Increases in Angular Motion and Stress Across Sacroiliac Joint: A Finite Element Study
,”
Spine
,
34
(
5
), pp.
E162
E169
.10.1097/BRS.0b013e3181978ea3
13.
Kiapour
,
A.
,
Ambati
,
D.
,
Hoy
,
R. W.
, and
Goel
, V
. K.
,
2012
, “
Effect of Graded Facetectomy on Biomechanics of Dynesys Dynamic Stabilization System
,”
Spine
,
37
(
10
), pp.
E581
E589
.10.1097/BRS.0b013e3182463775
14.
Sairyo
,
K.
,
Goel
,
V. K.
,
Vadapalli
,
S.
,
Vishnubhotla
,
S. L.
,
Biyani
,
A.
,
Ebraheim
,
N.
,
Terai
,
T.
, and
Sakai
,
T.
,
2006
, “Biomechanical Comparison of Lumbar Spine With or Without Spina Bifida Occulta. A Finite Element Analysis,”
Spinal Cord
,
44
(
7
), pp.
440
444
.10.1038/sj.sc.3101867
15.
Oktenoglu
T.
,
Erbulut
,
D. U.
,
Kiapour
,
A.
,
Ozer
,
A. F.
,
Lazoglu
,
I.
,
Kaner
,
T.
,
Sasani
,
M.
, and
Goel
,
V. K.
,
2014
,“
Pedicle Screw-Based Posterior Dynamic Stabilization of the Lumbar Spine: In vitro Cadaver Investigation and A Finite Element Study
,”
Comput. Methods Biomech. Biomed. Eng.
(in press).10.1080/10255842.2014.890187
16.
Panjabi
,
M. M.
,
2007
, “
Hybrid Multidirectional Test Method to Evaluate Spinal Adjacent–Level Effects
,”
Clin. Biomech.
,
22
(
3
), pp.
257
265
.10.1016/j.clinbiomech.2006.08.006
17.
Mulholland
,
R. C.
, and
Sengupta
,
D. K.
,
2002
, “
Rationale, Principles and Experimental Evaluation of the Concept of Soft Stabilization
,”
Eur. Spine J.
11
(
s2
), pp.
S198
S205
.10.1007/s00586-002-0422-x
18.
Niosi
,
C. A.
,
Wilson
,
D. C.
,
Zhu
,
Q.
,
Keynan
,
O.
,
Wilson
,
D. R.
, and
Oxland
,
T. R.
,
2008
, “
The Effect of Dynamic Posterior Stabilization on Facet Joint Contact Forces: An in vitro Investigation
,”
Spine
,
33
(
1
), pp.
19
26
.10.1097/BRS.0b013e31815e7f76
19.
Ko
,
C.-C.
,
Tsai
,
H.-W.
,
Huang
,
W.-C.
,
Wu
,
J.-C.
,
Chen
,
Y.-C.
,
Shih
,
Y.-H.
,
Chen
,
H.-C.
,
Wu
,
C.-L.
, and
Cheng
,
H.
,
2010
, “
Screw Loosening in the Dynesys Stabilization System: Radiographic Evidence and Effect on Outcomes
,”
Neurosurg. Focus
,
28
(
6
), p.
E10
.10.3171/2010.3.FOCUS1052
20.
Schnake
,
K. J.
,
Schaeren
,
S.
, and
Jeanneret
,
B.
,
2006
, “
Dynamic Stabilization in Addition to Decompression for Lumbar Spinal Stenosis With Degenerative Spondylolisthesis
,”
Spine
,
31
(
4
), pp.
442
449
.10.1097/01.brs.0000200092.49001.6e
21.
Stoll
,
T. M.
,
Dubois
,
G.
, and
Schwarzenbach
,
O.
,
2002
, “
The Dynamic Neutralization System for the Spine: A Multi-Center Study of a Novel Non-Fusion System
,”
Eur. Spine J
,
11
(
Suppl 2
), pp.
S170
S178
.
22.
Welch
,
W. C.
,
Cheng
,
B. C.
,
Awad
,
T. E.
,
Davis
,
R.
,
Maxwell
,
J. H.
,
Delamarter
,
R.
,
Wingate
,
J. K.
,
Sherman
,
J.
, and
Macenski
,
M. M.
,
2007
, “
Clinical Outcomes of the Dynesys Dynamic Neutralization System: 1-Year Preliminary Results
,”
Neurosurg. Focus
,
22
(
1
), p. E8.10.3171/foc.2007.22.1.8
23.
Wu
,
J.-C.
,
Huang
,
W.-C.
,
Tsai
,
H.-W.
,
Ko
,
C.-C.
,
Wu
,
C.-L.
,
Tu
,
T.-H.
, and
Cheng
,
H.
,
2011
, “
Pedicle Screw Loosening in Dynamic Stabilization: Incidence, Risk, and Outcome in 126 Patients
,”
Neurosurg. Focus
,
31
(
4
), p.
E9
.10.3171/2011.7.FOCUS11125
24.
Würgler-Hauri
,
C. C.
,
Kalbarczyk
,
A.
,
Wiesli
,
M.
,
Landolt
,
H.
, and
Fandino
,
J.
,
2008
, “
Dynamic Neutralization of the Lumbar Spine After Microsurgical Decompression in Acquired Lumbar Spinal Stenosis and Segmental Instability
,”
Spine
,
33
(
3
), pp.
E66
E72
.10.1097/BRS.0b013e31816245c0
25.
Meyers
,
K.
,
Tauber
,
M.
,
Sudin
,
Y.
,
Fleischer
,
S.
,
Arnin
,
U.
,
Girardi
,
F.
, and
Wright
,
T.
,
2008
, “
Use of Instrumented Pedicle Screws to Evaluate Load Sharing in Posterior Dynamic Stabilization Systems
,”
Spine J.
,
8
(
6
), pp.
926
932
.10.1016/j.spinee.2007.08.008
26.
Bozkus
,
H.
,
Senoglu
,
M.
,
Baek
,
S.
,
Sawa
,
A. G.
,
Ozer
,
A. F.
,
Sonntag
, V
. K.
, and
Crawford
,
N. R.
,
2010
, “
Dynamic Lumbar Pedicle Screw-Rod Stabilization: In vitro Biomechanical Comparison With Standard Rigid Pedicle Screw-Rod Stabilization
,”
J. Neurosurg. Spine
,
12
(
2
), pp.
183
189
.10.3171/2009.9.SPINE0951
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