Authors :
TUNG-HSUAN WU; M.D, RONG-DAR TSUO; M.D, TAI-HSIN TSAI
Volume/Issue :
Volume 7 - 2022, Issue 4 - April
Google Scholar :
https://bit.ly/3IIfn9N
Scribd :
https://bit.ly/37xRKEb
DOI :
https://doi.org/10.5281/zenodo.6516299
Abstract :
The purposes of this in vitro study are that to
investigate if the cord pretension and spacer in posterior
dynamic stabilization affects the flexibility in sheep
lumbar spine.
Methods
Eight sheep lumbar spine in the intact state, Dynesys
with neutral spacer and 300N cord pretension, Dynesys
with neutral spacer and no cord pretension, Dynesys with
300N without spacer, and rigid rod fixation were
evaluated. The range of motion (ROM) and neutral zone
(NZ) of flexion-extension, lateral bending and axial
rotation were measured calculated to evaluate the
flexibility of sheep lumbar spine.
Results
There were significant decrease the ROM and NZ in
flexion -extension, in lateral bending (ROM, p<0.001; NZ,
p<0.001) after implantation of Dynesys or rigid fixator. On
comparing the effect of the cord pretension, the ROM and
NZ in flexion-extension was significant difference between
the instrumentation of Dynesys with 300N pretension and
Dynesys without pretension was found (ROM, p=0.013;
NZ, p=0.037). On comparing the effect of the spacer, there
was no significant difference in ROM and NZ between the
instrumentation of Dynesys with spacer and Dynesys
without spacer in all principal motion direction. Dynesys
assembly without spacer showed more stiffness than rigid
fixator.
Conclusions
On the basis of this in vitro study, the kinematic
behavior of Dynesys is similar to the rigid rod fixation. The
flexibility of Dynesys was reduced when assembly with 300
N cord pretension. The cord pretension and spacer plays
important role in flexibility of Dynesy
Keywords :
Dynamic Neutralization Stabilization System, In Vitro, Sheep, Lumbar Vertebrae
The purposes of this in vitro study are that to
investigate if the cord pretension and spacer in posterior
dynamic stabilization affects the flexibility in sheep
lumbar spine.
Methods
Eight sheep lumbar spine in the intact state, Dynesys
with neutral spacer and 300N cord pretension, Dynesys
with neutral spacer and no cord pretension, Dynesys with
300N without spacer, and rigid rod fixation were
evaluated. The range of motion (ROM) and neutral zone
(NZ) of flexion-extension, lateral bending and axial
rotation were measured calculated to evaluate the
flexibility of sheep lumbar spine.
Results
There were significant decrease the ROM and NZ in
flexion -extension, in lateral bending (ROM, p<0.001; NZ,
p<0.001) after implantation of Dynesys or rigid fixator. On
comparing the effect of the cord pretension, the ROM and
NZ in flexion-extension was significant difference between
the instrumentation of Dynesys with 300N pretension and
Dynesys without pretension was found (ROM, p=0.013;
NZ, p=0.037). On comparing the effect of the spacer, there
was no significant difference in ROM and NZ between the
instrumentation of Dynesys with spacer and Dynesys
without spacer in all principal motion direction. Dynesys
assembly without spacer showed more stiffness than rigid
fixator.
Conclusions
On the basis of this in vitro study, the kinematic
behavior of Dynesys is similar to the rigid rod fixation. The
flexibility of Dynesys was reduced when assembly with 300
N cord pretension. The cord pretension and spacer plays
important role in flexibility of Dynesy
Keywords :
Dynamic Neutralization Stabilization System, In Vitro, Sheep, Lumbar Vertebrae