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MAGNETIC RESONANCE IMAGING
CLARITY OF BAGUERA C®, PRODISC C®
AND PCM ® CERVICAL
A NOVEL LUMBAR DISC REPLACEMENT DEVICE
BAGUERA® L : DESIGN AND BIOMECHANICAL
M. PEDRAM (1), P. ESPOSITO (2)
D. NORIEGA (1), M. ARQUEROS (2)
nterior lumbar interbody
fusion is a traditional surgical treatment for degenerative disc disease that remains
symptomatic despite non-operative management.
An alternative approach to fusion
surgery of the lumbar spine is to
restore motion to the diseased segment with a lumbar disc prosthesis.
Clinical studies have reported
increased biomechanical loading
at the adjacent motion segments
following fusion.
Use of BAGUERA® L may minimize this problem. In these biomechanical tests, the BAGUERA® L
implant maintained motion and
stability of the lumbar spine when
tested under physiologic motion
and loading conditions.
The goal of the disc prosthesis was
to replace the diseased disc while
preserving and/or restoring the
motion at the operated spinal level.
Pre-clinical test in an in vivo loading environment are the success
of such devices to confirm the
safety and efficacy.
A
he objective of this study is
to compare postoperatively
imaging characteristics of 3
cervical arthroplasty devices at the
level of implantation and at adjacent levels.
To assess adequacy of postoperative visualization of neural structures with cervical disc replacement, a study conducted in 2007
comparing several cervical discs
replacement has shown that titanium devices with or without polyethylene inlay allow satisfactory
monitoring of the adjacent and
operated levels.
The study concluded that devices
containing non titanium metals
prevented accurate postoperative
assessment with magnetic resonance imaging at the surgical and
adjacent levels.
T
Materials and Methods
Preoperative and postoperative
magnetic resonance imaging with
12 patients who had undergone cervical arthroplasty were assessed for
imaging quality. Four cases each of
Baguera C®, Prodisc C® and PCM®
devices were analyzed. Two independent radiologists scored twice
sagittal and axial T2 – weighted
images using the Jarvik four point
scale. Statistical analysis was performed comparing quality before
surgery and after disc implantation
at the operated and adjacent levels
and between implant types.
Hopital Clinico Universitario - Valladolid.
Center for Radiology Diagnosis - Valladolid.
Results
Preoperative images of patients in
all implant groups had high-quality images at operative and adjacent levels. Baguera C® device
allowed satisfactory visualization
of the canal, exit foramina, cord
and adjacent levels after arthorplasty (average of 44.75).
Visualization was significantly
impaired in PCM® (average of 25)
and Prodisc C® (average of 29.75)
cases at the operated level and in
both the spinal cord and neural
foramina.
At the adjacent levels, image quality was statistically poorer in PCM®
and Prodisc C® than the ones of
Baguera C®.
Conclusion
Postoperative visualization of neural structures and at adjacent levels
after cervical arthroplasty is variable among current available
devices.
Devices containing non titanium
metals (cobalt-chrome-molybdenum alloys in the PCM® and
Prodisc C®) prevent accurate postoperative assessment with magnetic resonance imaging at the surgical and adjacent levels.
Titanium device with polyethylene
Baguera C® allow for satisfactory
monitoring of the adjacent and
operated levels.
This information is crucial for any
surgeon who wishes to assess adequacy of neural decompression
and where monitoring of adjacent
■
level is desired.
Materials and Methods
The BAGUERA® L is an articulating lumbar disc replacement device
comprised of two titanium plates
coated with DIAMOLITH® that
1- Clinique St Martin - Bordeaux.
2- Clinique des Diaconesses - Strasbourg.
interact through a semi-constrained
(with or without controlled translation device) nucleus.
The titanium plates reduce artifacts
and allow for an MRI control.
The plates are coated with DIAMOLITH® to improve conductivity
and to eliminate the risk of wear
debris.
The BAGUERA® L concept allows
for choosing the mobility of the
nucleus intraoperatively, without
changing the superior or inferior
plates.
The movement of the mobile nucleus
is controlled to respect rotation
movements.
The shape of the inferior plate and
the nucleus enable an absorbability of up to 0.25mm thus allowing
absorption of shocks and vibrations 10 times more than a flat surface design.
The porous titanium coating as
well as the 10 upper and lower fins
guarantee primary stability of the
device and prevent it from being
expulsed or rotated.
This implant allows flexion/extension, axial rotation, lateral bending, and anterior/posterior translation.
Results
Wear testing was performed on
BAGUERA® L under normal physiological loads and motions in
order to quantify the amount of
wear debris generated by the
device.
This test consists in an application
of alternative compressive load
with a maximum of 2000N on the
prosthesis combined with a rotation movement for 20 million
cycles at 1,7Hz.
The wear or geometrical deformation value are absolutely correct
and so vlidate its resistance.
Static tests were conducted. The
ultimate compressive load was of
8404N for adisplacement of 1,26
mm.
The Yield compressive load was
4190N for a displacement of 0,53
mm.
Dynamic tests consisted of an
application of alternative compressive load comprised between 380N
and 3800N.
The system resists under these
conditions for 10 million cycles at
5Hz.
Conclusion
Extensive laboratory wear testing
has shown excellent wear characteristics of the BAGUERA® L
Lumbar Disc.
Compared to the intact spine, the
BAGUERA® L implant maintained
a natural range of lumbar mobility
and stability during flexion, extension, and lateral bending.
Unlike fusion, use of the BAGUERA®
L prosthesis to treat symptomatic
degenerative lumbar disc disease is
expected to minimize biomechanical stress at adjacent motion seg■
ments.
THÉRAPIE INTRA-THÉCALE ET ARTHRODÈSE RACHIDIENNE
POSTÉRIEURE : MISE AU POINT À PROPOS DE 7 CAS
ET REVUE DE LA LITTÉRATURE
C.DELECOURT , C. MORIN, D. CHOPIN ET S. CHAROSKY
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Une banque de données
de plus de 1000 articles
es IMC en particulier non
marchants peuvent bénéficier du traitement de la spasticité par voie intra-thécale et
d’une chirurgie pour scoliose avec
arthrodèse rachidienne étendue le
plus souvent jusqu’au sacrum.
L
Institut Calot, groupe Hopale.
Le Rachis - Tome 5 - N° 3 Mai - Juin 2009
11
L’association de ces 2 traitements
n’est pas sans poser de problèmes
liés à la technique chirurgicale et à
une éventuelle majoration de la
morbidité.
Matériels et méthodes
Il a été tenté de répondre à ces
questions par l’étude de la littéra-
ture et de la série de 7 patients
ayant bénéficié d’une thérapie
intra-thécale (TIT) avec pompe et
cathéter (KT) et d’une arthrodèse
rachidienne postérieure (ARP).
3 situations différentes sont rencontrées : le KT est présent lors de
la réalisation de l’ARP (2 cas), le
KT est mis en place dans la même