COMMUNICATION p7 : Interview with Dr Vincent Bryan ... - ArgoSpine

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N°6 - October 2002
News from the world of Spinal surgery and biomechanics
Special issue on :
Disc prosthesis
T H E O F F I C I A L A R G O S P U B L I C A T I O N
7Interview with
Dr Vincent Bryan
Executive Vice President of Medical
Affairs for Spinal Dynamics Corporation
JPSSSTSS
in Japan
12About
Dr Kiyoshi Kumano
:
The preconstrained
14ProDisc
disc prosthesis
with
Pr François Lavaste
16Interview
Biomechanics Laboratory
of ENSAM, Paris
with
Dr Thierry David
22Interview
Clinique Bois-Bernard
Argos North
America conference
32First
Breaking the frontiers

Summary
Communication
Interview with Dr Vincent Bryan 7
About JPSSSTSS in Japan 12
Interview with Dr Thierry David 22
Spine surgery at Tunis 28
Web review 42
Evaluation
Prodisc : the preconstrained disc prosthesis 14
Interview with Pr François Lavaste 16
3 rd poster presentation award - Argos symposium 2002 13
2 nd poster presentation award - Argos symposium 2002 30
Disc prostheses and arthrodesis in degenerative
disease of lumbar spine 44
Training
First Argos North America conference 32
18th annual CSRS-ES meeting 38
Fondation de l’Avenir for medical research 48
N°6 - October 2002
News from the world of Spinal surgery and Biomechanics

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Editorial
Alexandre TEMPLIER
ARGOS General Manager
Editor in Chief
( )
Dear Members and readers,
Mobility is one of the main functions of the spine, thereby the preservation of
spinal motion, when possible, is a major concern in spinal surgery nowadays. Thus,
in specific cases, spine arthroplasty may be an interesting alternative to fusion. But
what is the place of arthroplasty in today spine surgery and what are the best
indications for it ? Furthermore what choice do we have among the existing
prostheses ? How reliable are they ?
The answer to these questions may be found in the last 40 years of research and
development on disc prosthesis. Several types of prosthesis are today at the end
stage of pre-clinical study while others are in the phase of clinical trial. However,
in comparison with other artificial joint technologies such as those for the knee and
hip, progress in artificial disc technology has been fairly slow, even though latest
clinical results are quite promising. Why this discrepancy in development ? The
structural and functional complexity of the disc is certainly one of the major
reasons, while economic aspects may be another one. Moreover, the disc prosthesis
is supposed to replace only one out of three intervertebral joints, while the other
two remain intact, which makes the biomechanics of the artificial disc so different
from other joint prostheses. Most emphasis has been placed on lumbar disc, while
there are only few attempts directed towards cervical disc. Paradoxically, the
cervical prostheses, or at least the first one available today, (Bryan’s) seem to
progress faster. The explanation may be in the lack of multicenter evaluation of
lumbar prosthesis so far, although they have been largely evaluated locally in
several health care centers all over the world. All these topics are worthy matters
of debate. This is why we focused this issue on disc prostheses, and asked advice to
some of the best known specialists in the field.
We look forward to reading from you soon,
Christian MAZEL
ARGOS President
Warmest regards.
April 2002 - N° 5 ARGOS SpineNews 5

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INTERVIEW WITH
Dr Bryan, how did you come to
design a disc prosthesis ?
– In North West there is a very young
population which is very active in
outdoor activities, whether mountain
climbing, whether topping trees,
whether fishing and so on. Many
young people present to us with disc
herniations and early degenerative
changes in their spine and get
operated with the usual operating
procedure. Then these people are
coming to us after 5/ 6 years and in a
significant number of them, we find
ourselves re-operating not because
there was something that has failed in
the previous operations, their
symptoms have been relieved, but
rather that they were re-herniating or
developing degenerative changes at
the adjacent levels that were causing
them to return. And then they would
go back to the same jobs, and they
would come back again in the thirties
and we would operate them for the
third time. Just too many people were
being left with the situation where
they are becoming disabled because
we were fusing too many segments.
So you consider that the usual
procedure of fusion allows for
only a temporary relief of
symptoms ?
– That’s right. It relieved the
symptoms but it really did not treat
the disease. The fundamental disease
is that the biomechanical integrity of
the neck has to be maintained if one
expects a normal wear and tear
pattern. And once is fused or once is
degenerating then the biomechanics
of the neck change and the adjacent
levels pick up the shock and the load.
So I have been thinking about this for
many years - I had been influenced to
my early carrier by Howard Cloward
and others. These were the people
who had developed these anterior
fusion techniques, so I had a large
experience with them. In any event,
most of my early neurosurgical carrier
has been spent with both
microvascular as well as stereotactic
neurosurgery wherein the precision
and localization was very important to
the outcome, especially with
stereotaxis.
Stereotaxis is a means by which
one uses a frame which is screwed
onto the skull to localise a very small
lesion in the brain and you can
identify the target points and the
entry points as well.
Communication Interview with Dr V. Bryan
Doctor Vincent Bryan
Copyright© Spinal Dynamics Corporation
The brain surgery is a very
delicate surgery, isn’t it ?
– The surgeries in the brain are more
precision oriented because you have a
small target in the middle of the brain
and you don’t want to damage the
surrounding tissues.
On the other hand, when
approaching the situation in the
spine, and also having the benefit of
many people’s experience over the
prior 35 years, you are trying to solve
these problems and also use the
benefits of the advancements in
material sciences for the orthopaedic
community and also the
advancements in diagnostic
techniques such as CT scanning and
MRI scanning. So it was finally
possible to combine a fundamental
understanding physiology and the
pathology of degenerative disease and
apply to it this information of material
science having been brought about
over these prior 35 years. So, in 1993
I did the drawings of the device (disc
prosthesis) but I would like to point
out that equally important to the
device was the development of
precision instrumentations to place it
exactly.
In between the vertebral bodies ?
– Yes, and not just in between, but
exactly in between from front to back,
from right to left so that it was
perfectly balanced such that the axis
April 2002 - N° 5 ARGOS SpineNews 7

Communication Interview with Dr V. Bryan
Copyright© Spinal Dynamics Corporation
of rotation was exactly in the right
location. Whereas many of the
devices that had been developed, as
for example in lumbar spine, where
functional spacers moved but they
really did not cushion as the normal
vertebral disc.
We wanted to approach this in a
different way and we had a very good
fortune of beginning to work with the
biomechanics laboratory of the
University of Washington, which is
used by the team of the Boeing
aircraft people. So, we did have a very
sophisticated biomechanics
laboratory and personnel to facilitate
this and we worked with their
polymer chemistry laboratory to
basically create a disc which not only
could cushion but could also be very
resistant to wear, usually when some
polymer it cushions is softer and it
will wear faster. But the process to
which this is subjected in surface
chemistry is altered in such a way that
it is extraordinarily durable on the
outside while being very much more
resilient on the inside, springy if you
want. So we also wanted to change the
joint which in the human situation is
called an arthrodial joint which means
it is connected from one vertebrae
right through the disc to the other
vertebrae. When something is
connected that way, it is called
constrained, and constrained things
8 ARGOS SpineNews N° 6- September 2002
when you are using artificial material
tempt to wear down quickly. For
example, if you want to take a piece in
the middle and you move it back and
forth, it will fatigue and it will break;
whereas if its living situation, you can
move it back and forth and if it did
break, it could repair itself. But it
cannot happen of course with artificial
materials. So we wanted to change the
nature of the joint from an arthrodial
joint to restore something similar to
diarthrodial joint which is a joint
more like knee or elbow where there
is a membrane surrounding and there
is a fluid lubricant in it that
dramatically reduces the wear of the
surfaces. So this was the first such
joint that they made that way. There
were a number of technical hurdles
but they were addressed satisfactory.
Ultimately when we had completed
the device we wanted to test it early
and we spent the next two and a half
years building spine simulators.
Those simulators are running now
almost constantly testing these
materials. The device is basically
designed to restore a full range of
motion and also to provide for what’s
called coupled motions, which means
that when you flex you also translate.
You are not having only a pure flexion
but a combined motion of flexion,
rotation and translation which is the
real way the neck moves.
Also we wanted to have, as the real
neck works, a mobile axis of rotation
so that while the neck moves through
its position the axis of rotation
changes which is also important to not
overwork the facet joints. We also
wanted to re-establish what’s called
the entire column. All of those things
were accomplished by the device and
it was tested again in the simulators
for an extended period of time and
then we moved into the animal model.
It has been tested in adult male
chimpanzees which are as big as I am,
75 kg or more, and these are
remarkable animals wearing loads
more close to those in human than the
situation with the quadrupeds.
Chimpanzee is probably a very
close model to human. Is it really
the best one ?
– 98% of the gene type are the same
and the anatomy is very similar, and
they have an upright posture. This
was a survival study such that after
the end of the study we were able to
remove the devices and then go ahead
and fuse those vertebrae the way that
it presently could happen in standard
situation by interbody fusion and that
worked very well. So we were also
able to demonstrate that when you
put this device in, you could always
remove the device, go ahead and fuse,
if needed later.
Have you ever faced any
situation like this, to come back
to the fusion after having made a
disc arthroplasty with your
device?
– We are now over 700 of cases, well
over that number, and we had no reoperation,
not one. No is the answer.
The device seems really adapted
to human movements. Normally,
patients should live very long
with this kind of device without
having any problems.
Nevertheless, should patients
expect limitations of mobility or
any withdraw with it ? Did you
have any cases where you found
limitations in movement,

adjacent levels degeneration or
any other complications ?
– The motion that one sees after the
device is inserted is essentially the
same as the motion that is seen before
the devices is inserted. In other
words, if the joint was not moving
pre-operatively, that person is not a
candidate for the device. Because it
suggests an anomaly of the “front” of
the column which is perhaps
immobile but the middle of the
postural column may also have
degenerative at the point that they do
not allow motion even if you correct
the situation and you enter the
column. But if patients had had
motion pre-operatively the best
preponderance will show a motion
post-operatively. We are having a few
who have not. When we got back to
look at those, in the majority, an
overwhelming majority of those
simply were not evaluated preoperatively
to see if they had motion.
So we are not sure in some of them,
because films were not taken, if they
had motion and somewhere it was
thought that there was motion preoperatively
where in fact was not. I
have seen one case where the vision
for no motion after a period of time
post-operatively is unclear. But it is
hard to say because sometimes the
patients think they are moving their
neck, when you ask for some flexion
extension and after they just move
their head on the top vertebrae.
So you cannot really evaluate the
mobility at the level you are
interested in.
– That is exactly correct. In the case
that we are making reference to here,
sometimes it is difficult to know if you
really are seeing any motion at all. I
did think that the patient did have at
least some overall motion. And it
appeared that the amount of motion at
the level of the prosthesis was small.
Yet, there is this limitation in ability to
measure where there is a limited
amount of motion of about 2 degrees.
So you can see that there is some
motion that has been transmitted but
it is certainly not a full range of
motion. There are statistics on this
issue but probably those statistics
regarding motion will not bring this
out as to what the reason is for how
reduced motion was. But when we
did go back and reviewed all of those,
there was surprising that the principal
reason was that probably there was no
motion pre-operatively.
I think there will be a number around
10% where there is reduced motion
below 2 degrees. But the actual
reason for is probably in this kind of
category.
In general, it is not a very
common surgery. For the lumbar
spine, there are a lot of studies,
evaluation studies, prospective
studies that are developed in
several hospitals in Europe and
in the United States but it is not
a common surgery. Why is it so ?
The surgeons are quite used to
the knee and hip arthroplasty.
What happens with the disc
prosthesis?
– The principal reason is that up until
now, the prefered type of operation is
cervical discectomy and fusion, and it
is sort of a favoured operation for
neurosurgeons and orthopaedic
surgeons who are operating the neck
because patients do very well, they go
home quickly and they are usually
happy with the outcome. The
problem is that what really releases
the symptoms is the decompression.
When you take the pressure out the
nerve, you remove the herniated
fragment, you remove the bones spur,
the symptoms subside. The fusion is
being done because the anterior
surgical approach which removes the
disc in the process of getting the
herniated fragment or the bones spur,
leaves that interspace without a disc
and something has to be put there and
presently is fused either with bone or
with a cage, then fixed with some
plates and screws. But none of that
really is necessary. All of that is being
done simply because one chose to
take an anterior approach which has a
lot of advantages because the visibility
is good and patients do well.
However, the consequences of that
are really realized for in 5 or 6 years.
Communication Interview with Dr V. Bryan
That’s when people start to come back
for the second operation. And usually
by that time, the person is going to
different places, they move, they do
this or do that. Since they really look
at their outcome only for about 6
weeks, the surgeons have been under
the impression that everything is just
fine. Patients symptoms go away,
patients are satisfied, the bill gets paid
and that’s the end of it.
But in fact, what’s happening, if you
think of this in another way, what’s
called the end-stage of the
degenerative disc process is
spontaneous fusion and what the
surgeons is actually doing is
advancing the disease process itself.
In 1 hour of operating time he is
taking a functional space, destroying
the functional space and advancing it
all the way down stream to end-stage
disease. And in turn reducing marked
increased stress on the adjacent
levels, which when subjected to that
increased stress fail. And it takes them
a period of time to do that, the
literature is quite clear now, people
develop recurrent symptoms at a rate
of 2.9% per year. More than two thirds
of that group will come to reoperation.
So, in 10 years, about 29%
of people are having recurrent
symptoms, and more than 20% are
having a re-operation. But if you do
your first operation in the twenties,
your second operation in the thirties,
your third operation in the thirties, it
does not take long before you have a
very large population of people who
are not doing very well at all. So,
people have come to appreciate the
fact that it is important not to look at
this as just the patients’ symptoms but
to think of this once those symptoms
are present as that patient having a
disease which puts them on a fast
track, because adjacent levels will
degenerate more rapidly than they
would otherwise. But they can
treat this not just by doing a
decompression which is the same
whether you fuse or you put a
prosthesis in. Do not fuse if it is not
unstable. If it is unstable, fuse it, that
is what fusion was supposed to be all
about.
But if this is not unstable, you are just
fusing it because this is the approach
September 2002 - N° 6 ARGOS SpineNews 9

Communication Interview with Dr V. Bryan
that you were taught as a surgeon to
deal with the herniation or with other
symptom.
Which are the main indications
for this prosthesis ? Are there
any common indications for disc
prosthesis and for arthrodesis ?
Maybe in some cases, there is
confusion and the surgeon will
opt for fusion because he thinks
it would be the best solution.
There might be cases where it is
difficult to choose. Does it
depend on whether you can or
you cannot evaluate mobility ?
– You can always evaluate mobility if
you take the time to do it. What
happened is that the films are taken
and the surgeon never sees them and
then he goes to see them into the
operating room. By the time you look
at them, the patient is there and you
never really participate in taking of
the films. The fact is that I would
suspect that, at least for the numbers
that we have calculated here, over
95% of people presently being fused
in the cervical spine, who are
undergoing anterior cervical
discectomy and fusion presently, are
candidates for an artificial disc. So,
the vast majority, it looks like those
that are not candidates are those who
have no motion, or those that are
unstable or those that have other
disease states, which tend to weaken
the strength of the bone itself, such as
osteroporosis or rhumatoid artrosis
For the cervical spine it is quite
early to talk about the nucleus
prosthesis. But what is your
opinion on nucleus prosthesis in
general ? Are they as efficient as
the total disc prosthesis ? Are
the indications different?
– As you said, there are no nucleus
prosthesis for the cervical spine. The
experience is young in the lumbar
spine. In the lumbar spine, there are
perhaps reasons to consider a nucleus
prosthesis. I can discuss it in terms of
lumbar spine. But in the terms of
cervical spine, or frankly in terms of
the spine I guess in general, the
10 ARGOS SpineNews N° 6- September 2002
nucleus prosthesis is addressing part
of the problem but not the whole
problem. And since it is just as easy to
address the whole problem, it would
be preferred to address the whole
problem. In the lumbar spine,
however it is not just as easy to
address the whole problem
sometimes. So, there are maybe cases
so like a category of patients where
nucleus prosthesis as an initial
approach is a good one.
Since most of the evaluators in
Europe and in the United States
seem to have good results with
this prosthesis, what do you
think : is it an almost perfect or
already a perfect disc prosthesis
? Are there any further
developments you could suggest
given your experience ?
– We continue to learn every day of
course. I think this prosthesis is the
beginning. I guess I view it as the
model “T” as they say in America with
regard to the Ford Auto Company.
When they had their first car, it was a
model “T”. I think that is a lot that’s
right about it. There is so much more
to be learned as this prostheses are
put in. That will allow one to make
improvements of every type.
Biomaterials ?
-– We are very pleased with the
materials as they are. Actually all
kinds of material have been evaluated,
but we really are very pleased with
the materials as they are. On the other
hand, a large group of engineers
spend every day of their life
improving every millimetre of this
device. I don’t think they will ever
stop for the next 30 years. So I think
that there will be improvements. It is
a place to start. I think it was starting
at a very significantly high level. It’s
been extraordinarily well tested for
many years now. I think that is what’s
leading it to be clinically successful at
this point.
But by no means do I believe that this
is as good as it could get. That is for
sure!
I should hope that the whole process
will continue. And it will. So, to
answer to your question before, do I
believe that this is the beginning of a
change in the way that an unstable
degenerative disease is treated, when
there still has retained motion,
I most definitely do believe
that arthroplasty is the
way things will go in
the future.
According to
your
experience
in general,
but mainly in this
context, what would
be your advice?
– I think, that when
considering arthroplasty :
1. Start thinking of a patient who
presents with symptoms like
radiculopathy or myelopathy,
secondary to either a herniated disc
or a degenerative process as having
a disease. No longer should we
satisfy ourselves with treating the
symptoms alone, but we shoud
rather look to the long term effects
of the operations we are performing
and deal with the degenerative
process once the symptomatic has a
disease, which means reestablishment
of more nearly
normal biomechanics. That is what
it is all about. If you are not
thinking that way there’s absolutely
no reason to consider doing an
arthroplasty procedure. There is no
reason to do it because you can
solve the patients’ symptoms very
simply by doing a decompression.
Unfortunately, they’ll return. So
why is that such an important
answer ? Because it requires a
change in the minds of the
physicians. And unless they allow
themselves to do that, they go on to
retirement doing something which
is giving them good short terms
results.
2. The second one we didn’t discuss is
related to the fact that once making
the move to arthroplasty, it is going
to require a level of surgical
concentration, and precision
instrumentation unlike that which
Copyright© Spinal Dynamics Corporation

is typically required when doing
fusion procedures. This is because
the durability of the materials and
the appropriate biomechanics are
re-established only when the
device is properly positioned.
It is the reason why this
procedure may seem easier for
the neurosurgeon than for the
orthopaedic surgeon, given the
fact that the neurosurgeon is
continuously faced to high
precision surgeries ?
– When doing knee surgery, it was not
until they started to introduce
precision cut of the bones surfaces,
very precise cutting, placing jigs and
other such things. That is when knee
surgery took the leap into
contemporary success rates. So, in the
early days, using constraint knee
joints and much more arbitrary
placement, it was no success
for knee arthroplasty as it is today.
So though the neurosurgeon is used
to delicate intracranial operations, I
think that on the spine, both
disciplines have not required of
themselves in doing this type of
surgery in the neck, given the level of
precision that is required, nor have
they their instrumentation, that would
allow them to have that level of
precision. This basically takes sort of
reverse stereotaxis concepts and
applies them to proper propositioning
to get readily reproducible results.
This instrumentation allows us to
place the device and it allows the
device to be immediately stable as a
result of that precision. So that the
patient can wake up from the
operating table and, quite frankly, can
get up and walk around without a
collar, move the head all around and
go home.
Is surgical navigation useful in
this kind of procedure ?
– The system we use, is one we
developed here and it is called gravity
localisation system. We use gravity to
provide for navigational control. It is
not using an electronic means, such as
the Stealth unit, but clearly this is
navigating in a very unique novel and
extraordinarily reliable way. So, it
clearly has a navigation system. Could
you apply the other kind of systems to
it? Of course, you could. But frankly,
the time would be much longer, they
take a long time to prepare and to
register and it is simply not necessary
here because the precision we get is
greater than the precision that we
would get with the electronic
instrumentation.
Were there any special moments
in your experience that made you
change your way of thinking ? Or
get specific orientation in your
work?
– I was trained by a well-known
neurosurgeon whose name was Paul
Bucy. Most neurosurgeons in the
world know Paul Bucy. When I
finished the training, I remember him
putting his arms around my shoulder,
as he had the habit of doing with those
he trained, and he said : “You
remember, Vince, I did not train you
just to practice neurosurgery, but to
advance it because if you do not do it,
who is going to do it?” And what he
meant by that, he was not just talking
to me, he was talking to every
neurosurgeon, and what he was
saying was basically that : “Who else
is more qualified to identify where is
that need to be improved and had the
experience over time to actually be
able to do it. So, in a sense, when the
time is right and you know what the
Courtesy of Doctor Vincent Bryan
Communication Interview with Dr V. Bryan
problem is, you’ve been taking about
3 years, then do it. Do it basically! It
is your responsibility to do it.” I never
forgot that. And the opportunity came
to reduce my clinical practice and to
spend more time in a research lab
which we did in 1993, then moved to
spend 50% of time in a lab, and in
1995 close to 95% of the time. That’s
been that way, working with animals
and machines and other things, but
maintaining or at least trying to
maintain the highest level of basic
science so that we would never rush,
we could always go back and do the
basic work. Until we understood it
fully. So we had the luxury to get very
generous support from many people
to take our time to do it right. This is
what happened I think that was
probably a very critical moment there.
All along the way, there have been
many many others. But I do not want
to wear you out.
Thank you very much, Dr Bryan,
for this exciting depicting of your
adventure with the cervical disc
prosthesis.
– Interview by Anca Mitulescu
In short
Vincent Bryan is a Board Certified
Neurosurgeon and the Chairman and
Executive Vice President of Medical
Affairs for Spinal Dynamics
Corporation, which he founded in
1993 to develop the Bryan(tm)
Cervical Disc prosthesis and system.
Dr Bryan earned a Doctor of
Medicine Degree and completed his
neurosurgical residency with Dr
Paul Bucy in 1972, with subsequent
fellowships at the University of
Washington. Dr. Bryan has authored
many publications and given
numerous presentations on cervical
spine arthroplasty and related
subjects.
September 2002 - N° 6 ARGOS SpineNews 11

About JPSSSTSS
in Japan
“Dr Kijoshi KUMANO from
Tokyo is an active member of
ARGOS and a genuine friend
of our Society. We are pleased
to publish his brief
introduction to the Society he
founded 9 years ago - The
Japan Society for the Study of
Surgical Techniques for the
Spine and Spinal Nerves - with
the ambitious goal to bridge
the expertise of orthopaedic
surgeons and neurosurgeons
together. I enjoyed the
privilege to attend six editions
of the annual congress which
permits to Asian, European
and American Spine Surgeons
to share and confront the
newest surgical techniques and
ideas with Japanese colleagues
at the highest level, and I can
say that the ever-renewed
success of his bold initiative is
the best proof how right his
brilliant intuition was and
remains. We wish him a frank
success for the next JPSSSTSS
forum, well aware how
challenging such a meeting
may be.”
12 ARGOS SpineNews N° 6- September 2002
– CM. Laager
From left to right : Pr Jean-Paul Steib, Dr Kiyoshi Kumano, Dr William Blake Rodgers
IT IS A GREAT pleasure to
introduce our society to the
international community of spine
surgeons : The Japan Society for the
Study of Surgical Technique for Spine
and Spinal Nerves. (JPSSSTSS) on
this occasion. Nine founding
members, both orthopedic surgeons
and neurosurgeons, started our
society in 1993 with three objectives:
1. Motivated participation of
individual members, 2. Keeping
abreast with the international
community 3. Interdisciplinary
meeting of orthopedic surgery and
neurosurgery. The first annual
meeting was held under the
presidency of Dr Kiyoshi Kumano in
Tokyo in 1994. Since then the number
of members has increased to 400 and
eight annual two-day meetings have
been successfully held with about two
hundred spine surgeons attending
each meeting. There have been more
than ten foreign guest lecturers at
each meeting to give guest speeches
or to conduct hands-on sessions of
spinal surgery. Each meeting has had
main themes put on focus such as the
posterior approach of the cervical
spine, the operative strategy of spinal
disorders of the aged and new surgical
techniques of spinal surgery proposed
in the Kyoto meeting in 2001. In each
meeting we found increasing interest
among members in exchanging and
sharing knowledge and surgical
techniques of both orthopedic and
neurosurgery. In dealing with the
same diseases of spine and spinal
nerves there have been always
different approaches and different
ways of handling between us. By
meeting together we are now able to
get new ideas and suggestions from
each other. It is indeed the first step to
organize both orthopedic and
neurosurgeons to join together to
create a new independent specialty
for disorders of the spine and spinal
nerves in the near future. Our 9th
annual meeting of JPSSSTSS was
held in Nagoya city on 14 and 15
September 2002. under the
presidency of Dr Yuichiro Nishijima
who is well known as a spine surgeon
of minimum invasive spine surgery in
Japan. Main themes were 1.
minimally invasive spinal surgery,
2.lumbar intervertebral body fusion
and 3. difficult cases of spinal surgery.
Our homepage is available for further
details : www.jpstss.com
We hope many European spine
surgeons will be interested in our next
meetings. ■
– Kiyoshi Kumano, MD
Secretary of JPSSSTSS

THIRD POSTER PRESENTATION
AWARD - ARGOS SYMPOSIUM 2002
Lateral placement of a single cylindrical
threaded cage in 360° lumbar interbody
fusion for lumbar degenerative disorders
Good positionning of the cage
Purpose:
The purpose of this paper was to
study the efficacy of a single
cylindrical interbody cage in 360
degrees of fusion for degenerative
lumbar disorders either by
endoscopic surgery of by minimally
opening surgery.
Cage with posterior rod and screws instrumentation
Materials and Methods:
There were 43 patients who
underwent lateral placement of a
single cylindrical cage together with
pedicle screwing in 360 degrees
lumbar interbody fusion for
degenerative lumbar disorders since
1997. The mean age was 56 years. The
mean follow-up was 20 months. BAK,
TFC, NOVUS and HMA cages were
used. 17 patients were operated by
– WATANABE Kenichi MD, KUMANO Kiyoshi MD, MACHIDA Hideto MD,
NATSUYAMA Motonobu MD, UCHIDA Tsuyoshi MD,
Dept. of orthopedic surgery, Kantoh Rosai Hospital, Kawasaki JAPAN
endoscopic surgery
while 26 patients
were operated by
minimally opening
surgery. Results were
e v a l u a t e d
roentgenographically
about positioning,
migration (sinking),
sclerotic or clear zone
r e a c t i o n ,
dislodgement and
loss of lordosis.
Results:
19 cages were found in right place, 21
were in acceptable place but 19 cages
were in incorrect place on immediate
post-operative X-ray films. 51% of
cages were noted in migrated
position. Placement of cages was
better in minimally opening surgery.
Although no statistical difference was
noted, migration of cages was less in
younger age group, anterior location
in the disc space and long cages at
follow-up X-ray examination.
Conclusion:
Endoscopic surgical placement of
cylindrical cages needs a longer
learning curve. Cylinder cages alone
will not be strong enough to achieve
fusion event with pedicle screwing. It
may need bone grafting around cages.
Cylinder cages should be inserted at
anterior disc space and no longer
cages should be chosen to engage at
circumferential endplate vertebral
body. Osteoporosis was a risk factor. ■
Clear zone
Cage before migration
Cage migration
Bad positionning of the cage
(frontal and lateral view)
September 2002 - N° 6 ARGOS SpineNews 13

Evaluation The ProDisc
ProDisc :
the pre-constrained lumbar disc prosthesis
Dr Thierry Marnay,
Montpellier, France invented
ProDisc as an alternative to
spinal fusion for patients
suffering from degenerative
lumbar diseases of discal
origin, resistant to previous
conservative treatment.
Since 1990, Dr Marnay
implanted more than 250 disc
protheses in more than 170
patients under 65 years old
and a recent retrospective
study about the first 64 cases
(performed in collaboration
with Dr Villette, Dunkerque)
with a 7-11 year follow up
showed that most of these
patients experienced a
satisfactory clinical and
functional outcome.
Courtesy of Doctor Thierry Marnay
14 ARGOS SpineNews N° 6- September 2002
ProDisc concept :
As all disc prostheses, the ProDisc is
meant to restore the mobility at the
intervertebral level where the disc is
degenerated. The prosthesis is made
up of an inferior and a superior endplates,
both titanium made, to
encourage the bone growth into the
titanium and thus solidify the
construct and avoid
migration. A convex
shape dome of
polyethylene inserted
in the inferior endplate
articulates
with the concave
surface of the
superior one, thus
allowing for a motion
between the vertebral
bodies. On a kinematics
basis, this prosthesis has
only three degrees of
freedom, while the disc has six, so
it does not perfectly reproduce the
kinematics of the intervertebral discal
joint but cancels the shear forces
which overload the posterior facet
joints. On the other hand, this
prosthesis seems to give a solid
stability to the intervertebral joint.
Any antero-posterior or lateral
displacement is stopped, therefore
there is a good stability in those
directions. At the level of flexion
extension, lateral inflexion and axial
rotation, it has corresponding degrees
of freedom and should ensure an
almost normal motion in these
directions. From a biomechanical
point of view, this is a semiconstrained
prosthesis.
As for the surgical technique, the
anterior transperitoneal and
retroperitonial approaches are used to
place the implant in between the
vertebral bodies, depending on the
vertebral levels to be accessed.
Dr Marnay has recently published his
first study on the 64 operated patients
that received a disc prosthesis. A short
summary of his findings is presented
hereafter.
Patient Selection :
As in all cases of disc arthroplasty, the
patient selection is paramount. The

candidates for ProDisc are patients
between the age of the end of growth
and 65 years, suffering from
degenerative lumbar diseases that did
not react positively to previous
conservative treatment and that have
permanent and persistent lumbar
pain. Patients with too severe facets
degeneration, spine deformities,
stenosis, severe articular
degeneration and severe osteoporosis
are not candidates for disc
arthroplasty. Patients with previous
decompression may be selected for
arthroplasty, but those operated with
missing posterior elements following
laminectomy and/or facetectomy are
to be excluded as the risk of migration
and instability is too important.
Medical imaging investigation :
In order to detect any of these
abnormalities, Dr Marnay
systematically recommends both an
MRI and a CT imaging, conventional
myelography and discography. After
conventional X-Rays, that will show
the disc degeneration and the loss of
disc height, the CT scan is used in
order to expertise the articular facets
and to check their orientation as well
as to explore intracanalar pathology.
The MRI is particularly effective for
the detection of peridiscal
osteophytes that may indicate a risk of
spontaneous fusion after arthroplasty.
It will also provide the surgeon with
all the information on the ligaments
and on the adjacent discs. A
degenerated adjacent disc will favor
arthroplasty rather than fusion. The
vertebral bony status must be
analyzed with the Modic changes
classification.
In some cases, angiography may
prove useful in order to detect any
vascular abnormalities, thus
decreasing the risk of iatrogenic
vascular lesions.
Evaluation of the mobility :
The main purpose of disc arthroplasty
is to preserve the intervertebral
motion and provide stability, maintain
the proper intervertebral spacing and
act like a shock absorber, while
preserving the vascular, neural and all
other spinal structures. The
intervertebral mobility must be
evaluated pre- and post-operatively,
all along the clinical follow-up.
Dynamic sagittal and frontal X-rays
are compulsory for a good medical
practice in cases of disc arthroplasty.
They will allow for a local and global
analysis of the mobility in the
operated level and in the entire
lumbar spine.
Criteria for post-operative
clinical evaluation :
The evaluation of the global posture
must be checked on 30x90 cm upright
X-ray films providing the surgeon
with a global view of the spine and
pelvis in order to analyze postural and
balance parameters (pelvic tilt,
incidence, sacral tilt, sacral slope,
lordoses, kyphoses etc) as well as
intersegmental stability.
The maintenance of functional
intervertebral joint, especially the
articular facets, as well as the absence
of stenotic alteration, periprostetic
and intervertebral calcification must
be carefully checked.
As for the clinical scores, Dr Marnay
used the Lassalle-Beaujon score and
the Visual Analogical Scale for the low
back pain. Now he recommends SF36
and Oswestry scores for clinical
evaluation. Furthermore, the
radiculopathy, the quality of life and
the patient’s satisfaction are other
factors to be investigated.
General outcomes :
Evaluation The ProDisc
64 patients have been operated with
the ProDisc prosthesis between 1990
and 1993 and 55 were available for a
complete follow-up. Some of them
previously underwent either
discectomy or decompression.
As a global outcome, the immediate
complications were related to the
anterior approach and not to the
discal prosthesis and no long term
complications were noted, i.e.
anterior or posterior migration, intracorporal
subsidence. Moreover, no
adjacent level degeneration was noted
even after long term follow-up.
A significant improvement of the
quality of life and a high reduction in
lumbar and/or radicular pain were
observed in most of the patients and
only 4 patients required a posterior
approach revision and finally
underwent spinal fusion.
The main advantage of this prosthesis,
as of any disc prosthesis is precisely
that it does not inhibit a later fusion
by posterior approach, if needed.
Furthermore, there is no need to
remove the prosthesis in case of
fusion, since it will act as an
intervertebral spacer, maintaining the
disc height. Nevertheless, it is
essential that the surgeon be familiar
with anterior approaches and that he
keeps in mind the selection criteria. ■
– Thierry Marnay, MD.
Courtesy of Doctor Thierry Marnay
September 2002 - N° 6 ARGOS SpineNews 15

Evaluation Interview with Pr F. Lavaste
The first Biomechanics activity in
your lab began in 1972. How did
you started ?
– At that time, we were asked to study
the breaking strength of the different
parts of a lumbar vertebra.
We thus tested the vertebral body in
compression, the spinous process in
flexion, the pedicles… So all parts
constituting a vertebra were
mechanically tested up to their
breaking point. And the pedicles were
identified as being the most resisting
part of a vertebra.
This request came from Raymond
Roy-Camille in 1972, date at which
Raymond Roy-Camille had suggested
to stabilize the spine by using a
pedicular fixation. So our answer
completely followed the same way
that R. Roy-Camille was thinking of,
that is to say screw insertion in the
pedicle. Indeed, mechanically
speaking, the pedicle corresponded to
the strongest part of the vertebra.
That was the beginning of our activity
in the biomechanics field at the
ENSAM.
What was the role played by the
disc prosthesis in the
development of the Laboratoire
de Biomécanique ?
– We worked on the disc prosthesis
from 1974, that is 2 years later, always
with the team of R. Roy-Camille and
Gérard Saillant, and mostly with the
16 ARGOS SpineNews N° 6- September 2002
INTERVIEW WITH
Professor François Lavaste
Biomechanics laboratory of ENSAM
“We worked on the disc
prosthesis from 1974 always
with the team of Raymond
Roy-Camille and Gérard
Saillant, who asked us to study
a possibility to replace the
intervertebral disc following
the treatment of a herniated
disc…”
Copyright© Biomechanics laboratory of ENSAM - Paris
latter who asked us to study a
possibility to replace the
intervertebral disc following the
treatment of a herniated disc. By
working together, G. Saillant, R. Roy-
Camille and the Laboratoire de
Biomécanique which did not exist yet
at that time, we had the idea to
perform a silicone injection in the
cavity resulted from the treatment of
the herniated disc. Therefore we
searched for the silicones which
would have the same performance as
that of the intervertebral disc. So
mechanical tests were performed on a
series of silicones, which enabled to
select a silicone that seemed
appropriate as a substitute for a part of
the intervertebral disc since we were
only working on the cavity developed
following the curettage of the disc. We
then had to inject the silicone. We
chose an injection in liquid phase and
in situ polymerisation. We also had to
settle the problem of the air which
was introduced at the same time as
the silicone. Therefore we realized a
device with a vacuum pomp on one
side and with injection of silicone on
the other side. The void of air and the
injection of silicone were therefore
performed simultaneously. Then
polymerisation was made in situ. The
volume of the cavity was 2 cm 3 , which
is a small volume. The largest volume
was 4 cm 3 , when the treatment of the
herniated disc was the longest. Then
we realized simulations on fresh
cadavers to perform the technique of
injection. And just at that time was

published in the international
literature a similar attempt realized
by a team of German orthopaedic
surgeons from Cologne. Then with G.
Saillant, we met them and we noticed
that this team had had exactly the
same idea and that they had evaluated
this technique by injecting that
silicone on animals using St Bernard
dogs, having a vertebral skeleton with
dimensions rather close to the
dimensions of the human skeleton.
The only difference is that the statics
is not the same at all. But as far as the
operative technique was concerned,
this team was exactly at the same level
as us, that is to say that they were
injecting a silicone which was
polymerising in situ and they had
reached the animal experimentation
while we were evaluating it on human
anatomical specimens.
So there were two different
evaluations of the same
technique ?
– Two different and complementary
evaluations but originating from the
same idea. In the same time, attempts
have been made by another team
which had used a metal ball acting as
a substitute for the intervertebral disc.
It was a real disaster : the metal ball
went through the vertebral endplates
and obviously it could not work
properly.
Because it did not correspond at
all to the mechanical
performance of the disc ?
– Indeed, it gave a mechanical answer
which was completely different.
Therefore there was an immediate
intra spongy herniation of the metal
ball. All of these attempts have been
done at the same period.
Then we went on with G. Saillant.
Still working on anatomical
specimens, we equipped the vertebral
column with strain gauges. We thus
were able to prove that between the
deformations of the vertebral column
before introducing the “prosthesis”
(the question was only to replace the
nucleus) and after, the injection of the
silicone and the polymerisation were
rather different and that the injection
allowed to better distribute the
stresses on the vertebral endplates, so
to better distribute the deformations
on the vertebral body.
We obtained a 1 to 4 ratio in term of
deformation, therefore 4 times less
deformation when we were able to
inject the silicone, which is not
negligible. At the same time we were
keeping the intersomatic space thanks
to the injection of the silicone.
This work was communicated and
published in Ottawa in 1976. It was
the first international communication
of the Laboratoire de Biomécanique.
So, in a way, it was the entry
point of the Laboratoire de
Biomécanique on the
international scene ?
– Yes, indeed. And then it was
published in RCO (Revue de
Chirurgie Orthopédique) in 1978
under the name of R. Roy-Camille, G.
Saillant, C. Mazel and the ENSAM
team which was not yet at that time
the Laboratoire de Biomécanique.
So we can say that the disc prosthesis
is part of the first works of the
Laboratoire de Biomécanique.
Work thanks to which it began to
acquire an international
acknowledgment.
– Yes, the work on the nucleus
prosthesis enabled to present very
quickly the activities of the lab. So we
went on with this work with a team of
the CERMA, which is the Centre
d’Etude et de Recherche en
Médecine Aéronautique (Center of
Study and Research in Aeronautics
Medicine), depending on the French
Department of Defense. We made
this work with colonel Pierre
Candieu, who was army medical
officer, and thus we were given access
to the animal houses. So we were able
to evaluate this prosthesis on a
monkey, since the CERMA animal
houses had baboons, and we thought
that this type of animal was much
closer to the physical reality of the
Evaluation Interview with F. Lavaste
human body than the dog.
Therefore we injected the nucleus
prosthesis in the baboon with Pierre
Candieu’s team at the CERMA. It was
around 1980. This evaluation on the
animal model was working rather well
but very quickly arouse the economic
problem since we had to carry on, to
follow those animals and the cost was
relatively considerable. We were able
to show the feasibility of the studies
carried on at the CERMA but we
wanted to go further. And research
stopped at that point because we
could not find someone interested in
financing this type of research. The
manufacturers of silicone did not see
any interest because it was only a
question of a few cubic centimetres of
silicone, so for them it represented
only drawbacks with a risk of bio
incompatibility. Therefore they did
not follow this operation. As to the
manufacturers of surgical implants,
we were too much ahead compared to
what was done at the time to interest
them. It was rather the era of fusion.
So the research on the nucleus
prosthesis stopped there.
Did you go on with that research
later ?
– Not at the Laboratoire de
Biomécanique but other teams went
on with similar ideas. One similar
attempt is the one of Jean-Louis
Husson’s team from Rennes who
developed a disc prosthesis
constituted of a material quite
malleable which is injected through
the opening of the herniated disc and
which is rolling itself within this
cavity. So this idea was finally
resumed by other teams but a dozen
years later.
So it was too early to develop
such an idea when you began
the research ?
– Yes, far too early. It seems to me that
there already existed a patent on the
idea of injecting a product which is
rolling itself in the cavity of the
herniated disc, even at the time we
September 2002 - N° 6 ARGOS SpineNews 17

Evaluation Interview with Pr F. Lavaste
were carrying out our research. It is
true that there were plenty of ideas on
the disc prosthesis but there had been
no concrete realization, no concrete
experimentation. What we had done
with G. Saillant and R. Roy-Camille
was injection in liquid phase with in
situ polymerisation to avoid the risk of
migration of silicone fragments and
also of silicone propagation, by
injecting the whole in a latex
membrane placed inside the cavity.
Anyway, even nowadays, the disc
prosthesis is not really widely
used. This alternative to fusion is
not always considered. The
arthroplasty of the spine has still
to gain ground…
– At that time, R. Roy-Camille was the
first to fuse using pedicle screws and
it was precisely to find an alternative
to fusion that we considered this
solution to preserve the intervertebral
mobility and the intersomatic space.
We can say that the arthroplasty
of the knee, of the hip developed
quite quickly. It seems rather
surprising, in spite of the
research lead for some thirty
years, that the arthroplasty of the
spine is still in its early stages.
How can this “slow-paced”
development be explained ?
– The risk of the arthroplasty at the
spinal level is much more
considerable than at the level of the
knee or the hip. If the prosthesis
migrates posteriorly towards the
medullar cavity, the risk is very
important. I think that is the reason of
all those hesitations. Moreover,
particularly in the case of the silicone,
if this material migrates towards the
medullar cavity, it is a real disaster.
Concerning the experimentation on
an animal model, it goes very well but
we take no risk, we can allow
ourselves to make some attempts to
improve the surgical techniques, but
there is much difference between the
experimentation on an animal and the
experimentation on a human. I think
that is what explains the time between
18 ARGOS SpineNews N° 6- September 2002
the first ideas, the experimental
evaluation and then the beginning of
the first clinical evaluations.
Since then other designs have
appeared, including the SB Charity
prosthesis, which had an advantage
since they were mecanisms, such as
the articular prostheses of the knee,
therefore the risk was a little more
mastered. Yet there remained the risk
of nucleus migration towards the
medullar cavity. I am thinking of the
SB Charité prosthesis in particular.
There was also the risk of migration of
the prosthesis endplates through the
vertebral endplates.
Did the Laboratoire de
Biomécanique play an important
part in the development of the
SB Charité prosthesis ?
– The SB Charité prosthesis arrived at
the Laboratoire de Biomécanique a
long time after that, at the time when
Alexandre Templier was preparing a
post-graduate diploma in 1995-1996
taken before completing a PhD, when
Dr Jean Philippe Lemaire asked us if
we could study the performance of
the SB Charité prosthesis from a
biomechanical point of view. So we
implemented biomechanical
evaluations on this prosthesis using
anatomical specimens and we tested
this prosthesis as we test any spinal
osteosynthesis material, which
enabled to study the performance of
Copyright© Biomechanics laboratory of ENSAM - Paris
Finite element model of the lumbar spine
One of the first models of a functional unit
developped at the biomechanics laboratory
of ENSAM
the SB Charité prosthesis when the
spinal segment was loaded in
flexion/extension, in lateral inflexion,
and in torsion. We concluded that the
prosthesis had good performance on a
kinematics basis. We simply found
that there was no rigidity in torsion,
given how the prosthesis had been
designed. There was no limitation in
torsion and we noted excessive
mobility in axial rotation when the
prosthesis had been implanted, hence
a risk of overstress, of over constraint
at the level of the articular facets.
Therefore we suggested some
improvements of this prosthesis to
introduce a rigidity in torsion. At the
same time we developed, within the
framework of Alexandre Templier’s
project, a finite element model of the
SB Charité prosthesis implanted on a
vertebral segment.
What was the point of this
model ?
– This model allowed us to
corroborate what we had been able to
exploit and examine experimentally
with the numerical simulation. So we
noted again, by numerical simulation,
that there was an excess of mobility in
axial rotation and that this excess
mobility generated stresses at the
level of the articular facets, as soon as
torsion torque was applied, and that
on the other hand, for the other
solicitations in flexion/extension and
lateral inflexion, the performance was
correct, as we already noticed during
the experimentation on specimens.
Therefore there was a coherence
between the numerical study and the
Copyright© Biomechanics laboratory of ENSAM - Paris

Copyright© Biomechanics laboratory of ENSAM - Paris
experimental one. Finally this work
lead to several publications by Jean
Philippe Lemaire and Alexandre
Templier.
What are your conclusions on
this prosthesis ?
– If we want to summarize on the
biomechanical characteristics, in
terms of kinematics, this prosthesis
has a five degree freedom, the only
degree of freedom which is missing
on this prosthesis is compression, the
polyethylene core being quite rigid.
On the other hand, it has degrees of
freedom in flexion/extension, in
lateral flexion, in axial rotation, and in
antero-posterior or lateral shear
(thanks to the bi-spherical joint). So
we can say that this prosthesis is
subjected to little internal stress, as
for the prosthesis of the knee. This
prosthesis is self- adaptative in
kinematics, that is to say that the
instantaneous center of rotation of the
over-lying vertebra compared to the
under-lying vertebra remains free
In vitro experimentation for the nuclear
prosthesis.
thanks to the
design of this
prosthesis.
And what do you think of the
other disc prostheses ?
– Another disc prosthesis had been
proposed, with a hinge joint, and I
think we can compare it with the
reconstructive hinge prostheses of the
knee, which are subjected to too
much stress and have difficulty to
function, or at least to be long-lasting,
because the stress is too considerable
since there is only one degree of
freedom (flexion-extension).
At the end they will not restore
the real movement of the spinal
segment.
– No, they will wear out very quickly
at a given moment. I also spoke of the
ball-type prosthesis right at the
beginning. This idea was abandoned.
There was another prosthesis of
Evaluation Interview with F. Lavaste
spherical type, a little like the hip
prosthesis. On a kinematics basis, this
prosthesis does not correspond to disc
kinematics which has 6 degrees of
freedom, whereas the spherical
prosthesis has only three (it can only
rotate and not translate).
Nevertheless, this prosthesis,
although it is submitted to much
stress, has some interests, particularly
to stabilize the intervertebral
articulation. Any antero-posterior or
lateral displacement is stopped,
therefore there is a good stability in
those directions. At the level of flexion
extension, lateral inflexion
and axial rotation, it has
corresponding degrees of
freedom. Resuming the
parallel with the knee
prosthesis, we can say that it
is a semi-constrained
prosthesis. Concerning the
components of this
prosthesis, the inferior
endplate of the prosthesis
has a sphere and the
superior endplate has a
spherical cavity.
This prosthesis has been
developed by a Belgium
surgeon and resumed by Dr
Thierry Marnay and seems
to develop in the United States.
Finally there is a last type of
prosthesis, the Silent-Block type
prosthesis and a patent was registered
by the CEA (French Commissariat
d’Energie Atomique), by Roy-
Camille’s team and myself, which
resumes the idea of the nucleus
prosthesis. With this type of
prosthesis, all the disc is replaced by a
malleable material having a continuity
like the intervertebral disc. Today this
prosthesis is still under development.
Thank you very much for this
interview.
– Interview by Anca Mitulescu
September 2002 - N° 6 ARGOS SpineNews 19

Communication Interview with Dr T. David
How did you start to work with
the disc prosthesis ?
– I began to get interested in
prostheses at the Research
Laboratory at Calot Institute. As I
took an interest in prostheses, I had
seen prostheses in silicone, then I
read, since at that time we had far
more time to read than nowadays, a
summary in English in an article
published in a German journal,
Zeitschrift fur Orthopedie, in 1987,
written by Schellnach and Büttner
who were presenting their first results
on the SB Charité prosthesis. I wrote
to them, they invited me. So I went in
Germany, in East Berlin. I think that
is the reason why nobody believed
that it could work, because it came
from the East. Therefore, they never
welcomed visitors. I think I was the
first to go there. They gave me a warm
welcome, I saw two prostheses and
they even left me in a room with
patients, the first patients operated
with the Charité prosthesis. I could
speak to most of them in English. I
came back, I was convinced that it
was good, that we had to do that. So I
asked them to come to Berck to help
me with the first prosthesis. It was the
first one in France. They came on
January 31 st , 1989. I also convinced
Daniel Chopin, which was not an easy
thing, but he was ready to see it all the
same. That is how I began to implant
those prostheses.
Then I moved to Bois Bernard and
here I continued to implant
prostheses, during my liberal time,
which was not obvious at the
beginning because we
22 ARGOS SpineNews N° 6- September 2002
INTERVIEW WITH
Doctor Thierry
David
Bois Bernard private hospital
Dr Thierry David was a house
surgeon in Paris at Beaujon
hospital and at Pontoise
hospital. It was at that time
that he started to operate
scoliotic patients. He then
went to Berck at the Calot
Institute where he worked with
M. Cauchois, as a house
surgeon, Then, at the end of
his training as a house surgeon
in Berck, after one year spent
with M. Cauchois, he worked
for 6 months with Daniel
Chopin and then one year with
M. Maurel in paediatric
surgery. Then he came back as
registrar with M. Deburge.
After that, he finished his
residency with Daniel Chopin
at the Institut Calot at the end
of 1985, while returning in
Paris once a week to continue
with the spinal cases at
Beaujon hospital. He stayed in
Berck for 5 years where he
performed a lot of scoliosis
surgeries with Dr Chopin and
also some degenerative
surgeries. In 1990, he resigned
from Institut Calot and moved
to Bois Bernard Private
Hospital.
did not really know whether it worked
or not. But we did not have many
problems at the beginning since the
results were not bad, there were not
too many complications.
Is it a relatively easy surgery or
are there some particular
constraints ?
– It is not easy to implant a disc
prosthesis properly. At the beginning,
we did not have all the sizes that we
have nowadays, we had too small sizes
and they were often either a little too
much on the right or a little too much
on the left, not really well-centered,
that is why they were not working
properly. It was good at the
beginning, during one year, two years,
three years, then after a while, it was
not so good and we had sometimes
cases of spontaneous fusions, or back
pain since the articulations did not
work anymore. So on the first two
years, I had operated again quite a lot
of those patients for arthrodesis. 13
had a secondary arthrodesis, out of all
the patients I had operated in the first
2-3 years, so we concluded that we
needed biggest sizes and that they
had to fill in the maximum space
possible.
French surgeons have conducted
several evaluation studies on this
prosthesis even though it has
been designed by German
surgeons. Why ?
– The French were at the head of the
list simply because, given the political

changes that occured in Eastern
Germany following the fall of the
Berlin Wall, the German surgeons I
worked with had a lot of difficulties to
continue their work. Some of them
were simply forbidden to operate
anymore. So in 1990, they only had 75
prostheses and that was all. So the
French surgeons resumed their work.
In France, Schellnach implanted
prostheses with Dubois, with
Lemaire, with myself, etc… Dubois
implanted twelve prostheses and then
stopped but he told me that his
patients were not so bad. He had the
same problem of sizes. Onimus also
implanted some and I do not know
why he stopped. I think that Jean Paul
Steib implanted one or two, in
Strasbourg. In brief, at the end, we
were only two to go on with the
prosthesis in France: Jean Philippe
Lemaire and myself. There was also
Zeegers, a Dutch surgeon from
Maastricht, who had a lot of problems
in the Netherlands because of the
prostheses and who is now in Munich,
in a completely private hospital,
where he goes on to implant
prostheses.
So at the end the situation was that
people who continued with the
prosthesis had nothing to do with
Germany. Just because of political
matters. It is only now that Western
German begin to implant some, once
they had seen that quite a lot of
surgeons worldwide are implanting
the prosthesis. And Link is located in
Hambourg so they have relationships
with German surgeons, that is why
now they are implanting a lot of
prostheses. But now they have to face
competition with Prodisc.
Did the indications evolve with
time ? Were there complications
due to wrong indications ?
– Yes, everything evolved. For
example, if the articular processes are
not good, it is not a good indication. It
is the same if the disc is herniated too
much because often when the disc is
herniated too much, there is not much
mobility anteriorly. But on the CT
scan we can see the articulations and
if the patient is rather young, we can
say that it will work. When we restore
the height, the articulations have to
work behind. When the disc is
herniated too much and the patient
has already been operated before, we
must not restore the height too much
because it can often pull on the nerve
roots. So on the patients who have
already been operated, there is a risk
of paralytic problems.
The other evolution in the indications
comes from the fact that before we
only operated the patients suffering
from low back pain. Now we also
operate the patients who have a
relapse and who suffer from a disc
herniation at the same level. Instead
of re-operating them by posterior
approach, by performing a
laminectomy or an arthrodesis, we
prefer to treat them by anterior
approach.
Provided that there is no
instability ?
– It doesn’t matter because when we
restore the height, the instability can
be treated thanks to the prosthesis. It
is a discal instability so even if the
ligaments are slack posteriorly, if we
give height to the disc we stretch all of
them again, only by anterior
approach. I had some patients
suffering from instabilities who are
very fine today, with long follow up.
What is important is to restore the
height.
Did you happen to have some
cases for which the indications
match up the indications of
arthrodesis ? How do you
manage those situations ? How
do you make a therapeutic
choice ?
– I don’t perform a lot of arthrodeses
for low back pain, except on the
spondylolisthesis. The prosthesis does
not treat the spondylolisthesis, nor the
pars defect. If it is a degenerative
spondylolisthesis, a priori we operate
Communication Interview with Dr T. David
them because there is a stenosis and
therefore we treat them by posterior
approach. A prosthesis on a narrow
canal will not work because there is
the risk to have cauda equina
syndrome complications. We cannot
perform a distraction on something
which is already compressed. If we
perform a distraction, the patient will
have paralytic problems. So when
there is a spondylolisthesis, there is
often an arthrosic stenosis, therefore I
treat everything by posterior
approach, laminectomy, graft and
instrumentation, and it works very
well.
On the other hand, on the lysis, we
can discuss it. I have already had a
case on which I performed both, a
pars defect repair and a disc
prosthesis in a young patient. In that
case, we treat everything. But I do not
perform that on every pars defect. If
there is a severe discopathy, I only
perform a pars defect repair, but if I
have a case of very positive
discography, in young patients, who
certainly do not want to have an
arthrodesis, in this case we can
imagine both. It means two surgeries,
by posterior and anterior approach,
but if it can preserve their mobility,
then it is worth it.
Precisely, speaking of mobility, it
is a particularly mobile prosthesis
with 5 degrees of freedom. Is
there not a risk of excesive
mobility in axial rotation ?
– This prosthesis is even more mobile
than a normal disc since it has no
rigidity except in compression. But
the excessive axial rotation is stopped
by the articular processes posteriorly
and by the ligaments anteriorly. That
is the reason why it is important to
suture the ligaments. Tensing the
ligaments by restoring the height
limits the axial rotation. On the other
hand, we must not force it, we must
not have them make rotations too
early. The problem is that the axial
rotations will have to be measured
and for the moment we have no axial
rotations measurement. It is always
September 2002 - N° 6 ARGOS SpineNews 23

Indication for fusion in
lumbar disc herniation with or
without previous surgery. Is there
a place for disc replacement ?
Thursday 30 th and
Friday 31 st January 2003
Maison des Arts et Métiers
9bis avenue d’Iéna PARIS XVI
This year we
deeper into
indications of fu
herniation with
surgery. Can fu
option as a firs
herniation in se
replacement co
but is there an
stage of pathol
these intermed
really avoid fusi
the cases of pr
patients, (chem
percutaneous n
conventional di
the adequat op
Indeed, when a
Argos association - 64, rue Tiquetonne 75002 Paris FRANCE - Phone +33 3 21 21 59 64 - Fax +33 3 21 21 59 70 -

would like to go
details on the
sion in disc
or without previous
sion be a good
t treatment for disc
lective cases ? Disc
uld be an alternative
indication at this
ogy ? By considering
iate options can we
on or just delay it ? In
eviously operated
onucleolysis,
ucleotomy, laser or
scectomy) is fusion
tion and when ?
nd why do we
Email : marjorie@argos-europe.com
Faculty (left to right)
Pr Dieter GROB
Pr Bernard JEANNERET
Dr Jean-Philippe LEMAIRE
Dr Thierry MARNAY
Organizing committee
Dr Pierre ANTONIETTI
Dr Laurent BALABAUD
Dr Philippe BEDAT
Dr Jean-Paul FORTHOMME
Dr Franck GANEM
Dr Frank GOSSET
Dr Alain GRAFTIAUX
Pr Pierre KEHR
Dr Christian MAZEL
Pr Jean-Paul STEIB
Dr/Ing Alexandre TEMPLIER
Dr Richard TERRACHER
choose to perform spinal fusion in
primary or recurrent disc herniation ?
To answer these questions, we
would like to have your advice in
order to define together the best
indications for fusion in disc
herniation. We are sure that the
collegial atmosphere of this meeting,
favoring convivial and rigorous
debates, will once again stimulate all
of us for a fruitful discussion on this
topic and on all related aspects -
indications, clinical criteria, surgical
strategy and techniques. We
sincerely hope that this meeting will
be another great success and are
looking forward to welcoming you in
Paris next January.
Pre-programme
➥ Thursday January 30 th , 2003
13h20 to 17h00
Fusion as the first treatment
in lumbar disc herniation. Is
there a place for disc replacement ?
- indications, clinical criteria
- strategy and surgical method
➥ Friday January 31st , 2003
8h00 to 12h00
Fusion in the treatment of
previously operated lumbar disc.
Is there a place for disc
replacement ?
- indications, clinical criteria
- strategy and surgical method
➥ Friday January 31st , 2003
14h00 to 17h30
Oral presentations
Call for abstracts :
➥ Information and abstract submission at :
www.argos-europe.com/Abstract_Form.html
On the theme :
“Indication for
fusion in
lumbar disc
herniation
with or
without
previous surgery.
Is there a place for disc
replacement ?”
SIMULTANEOUS TRANSLATION
www.argos-europe.com

Communication Interview with Dr T. David
Courtesy of Doctor Thierry David
difficult to measure axial rotations on
dynamic X-rays. We would certainly
be able to measure them according to
the pedicles, but as it is a question of
a few degrees, it is not obvious. The
normal rotation is around 3 degrees
while the measurement techniques
are 5 degree precise. Finally, my
feeling is that there is no excessive
rotation.
To conclude, if the ligament
system is healthy, normally there
is no problem of hyper mobility in
torsion ?
– No. I think that the less the
prosthesis is constrained, the better it
is. First because there are several
rotation centers, as for a normal disc,
whereas the semi-constraint
prosthesis has only one rotation
center, then the articular processes
will be much more loaded. But there
is no study on the semi-constraint
prosthesis of Thierry Marnay. We
don’t know yet how it is going.
Moreover I conducted a study on the
constraints in the discs in relation to
arthrodeses. I stopped the study but I
have a series of patients with a 9 year
follow up on whom I studied the
overlying disc in relation to its preoperative
condition, and it is perfect.
There is no degeneration at the
overlying level whereas in the case of
an arthrodesis, the disc degeneration
at the overlying level is one of the
most embarrassing complications. To
sum up, we consider to have a good
result of the arthroplasty when the
segment is mobile in all directions
and in a well-balanced manner, that is
to say in sagittal flexion/extension, in
left/right axial rotation, in left/right
lateral flexion. An unbalanced
mobility is not a good result. Then
26 ARGOS SpineNews N° 6- September 2002
there are people who developed an
ossification around the prosthesis, as
in the case of the knee prosthesis and
this ossification will reduce the
mobility. We do not know the cause of
this phenomenon but when it
happens it can lead to spontaneous
fusion. It surely depends on the
power of each of us to ossify
haematomas which develop during
the surgery.
What will then be the part,
according to you, of the
arthroplasty in the treatment of
disc pathologies ?
– Arthroplasty is a good thing but we
must not exaggerate. We can not
implant prostheses in all cases. It is
not because people have some back
pain that we will immediately implant
a prothesis. That is the risk. Some
surgeons will implant one when it is
needed and when it is not. The
advantage is that the prosthesis is
implanted by anterior approach.
Surgeons operating the spine by
anterior approach are not that many.
That will be a limitation.
Then there are some cases which are
not a good indication at all for a
prosthesis. Like 70 year-old people
having an osteoporosis in an advanced
state. In those cases a prosthesis can
not be implanted. The prosthesis
must be useful and give a good
mobility in very active patients. At 30
year old people it is worth it, even at
60 in some cases. I operated a 60 yearold
patient who was a former regular
soldier, very active, who used to make
a lot of sport. His organism was that of
a 40 year-old person. I certainly could
not make an arthrodesis since he had
a very active life.
It explains why more time was
needed so that the disc
prosthesis be “adopted”
compared with the other types of
prostheses ?
– In my opinion, it is rather due to
economic factors. In France we began
a long time ago while in the United
States, they began 2 years ago and
now it is making very good progress.
And just because the American are
more open-minded, there are less
conflicts of interests. I also think that
the prostheses have suffered from the
presence of cages. The persons who
were involved in the development of
the cages have systematically refused
the prosthesis because the disc
prosthesis means the end of cages.
The day when the prosthesis arrives,
it is the end of cages. Anyway, the role
of cages is only to restore the height.
But in the spondylolisthesis, for
example, if the height is restored
posteriorly, we de-lordose. So we
must not restore the height, we must
decompress the nerve roots and
stabilize. Cages have been used a lot
for low back pain. The results were
good because the disc was completely
removed, so the source of pain was
also removed. That is the reason why
it gave good results.
With the SB Charité prosthesis, the
disc is also removed but the mobility
is preserved. There is no more risk of
pseudarthrosis. The bad result of a
prosthesis is fusion, which is a good
result for an arthrodesis.
So, at worst, we have a fusion ?
– Exactly. At worst, if we made a
mistake about the indication and if the
articular processes are bad, the
patient will have low back pain,
therefore we will have to make an
arthrodesis by posterior approach
while keeping the prosthesis. If you
put screws and rod posteriorly, the
prosthesis will play the role of a cage
since there will be a spontaneous
fusion anteriorly.
So it is an alternative which
allows not only to avoid fusion
for precise indications, but also
to temporise fusion in certain
cases. In this case, you have the
possibility to go backwards and
make a fusion.

Courtesy of Doctor Thierry David
Courtesy of Doctor Thierry David
Example of a failure with the SB Charité disc
prosthesis : early post-operative X-ray.
– This is exactly what I say to my
patients. And it is the same for the
pars defect repair. It is another
philosophy. It is a step ahead. If it
does not work we can always make
the arthrodesis whereas if we make an
arthrodesis, we have no possibility to
go backwards. Since 1992, when I
operated 60 patients, out of the 60, 13
had an arthrodesis. And since then, I
have now 350 patients and no more
case of arthrodesis. And for the pars
defect repair, I have no case of
arthrodesis whereas I started in 1995.
So all of these patients are not very
well but they have not pain enough to
have an arthodesis. Therefore, it is
interesting all the same. In my
opinion, arthrodeses for low back
pain, without deformation, will not
have a lot of indications anymore.
I think it has allowed to think
differently. Not to treat the X-rays but
rather to try to treat the patients, to
search for the origin of pain. With the
pars defect repair, it is the same.
Infiltrations in the lysis allow to see if
it works or if it does not. And we treat
there the origin of pain. X-rays are
taken every day and there are plenty
Post-operative X-ray at 5 years follow-up for successfull surgery with the SB Charité disc
prosthesis.
Communication Interview with Dr T. David
of people who have herniated and
degenerated discs but who have no
pain. Disc degeneration is a normal
ageing process which starts from 30-
35 years old onwards. But some
people have 2-3 degenerated discs,
others 10 or 12. And not every
degenerated disc is painful. Why are
some discs painful and others not, we
will probably know the reason later.
One of the reasons is genetic. Then
there are chemical factors. Some discs
are secreting particular substances.
Those patients will be treated. The
future holds genes therapies for disc
degeneration. It will certainly be the
end of spinal surgery for degenerative
pathologies. We are not yet at that
stage but it will come.
To conclude, what is the thing
that had the greatest impact
during this experience with
arthroplasty, with this disc
prosthesis ?
– I think I was very lucky to fall on
this article summary and to go to
Eastern Germany. It changed my life,
my clinical practice. It enabled me to
be invited in many meetings, to meet
extraordinary people. Yet there is
something incredible in that story :
the fact that it came from the East and
that nobody thought that the things
coming from the communist world
could work, particularly in medicine.
I think it is still the case. In Russia, for
example, some people found
extraordinary things that have never
been divulged. Like Illizarov, for
example, who was one of the few
eastern Europeans that managed to
communicate his technique…So all
these things are the consequences of a
short moment when I read a small
abstract. Quite fantastic, isn’t it ? ■
– Interview by Anca Mitulescu
September 2002 - N° 6 ARGOS SpineNews 27

Communication Spine surgery at Tunis
SPINE PATHOLOGY was
dominated for quite a long period
by the Pott disease and by the
sequella of the anterior acute
poliomyelitis. Acute poliomyelitis has
been eradicated since 1972 and the
number of tuberculosis cases is
drastically decreasing with the
sanitary development in Tunisia as
well as due to systematic vaccination.
These facts explain why infantile and
adolescent scoliosis, either idiopathic,
congenital or paralytic, is nowadays
the main pathology in spine surgery.
The instrumentation used to treat
scoliosis has evolved along the years.
After Harrington and Luque
instrumentations, we passed to the
new generation of instrumentation
such as CD, CCD, SCS and many
others. Our strong collaboration with
Pr Jean Dubousset allowed us to
establish a good practice in pediatric
spine surgery in Tunis.
Surgical treatment of spine trauma
developed almost simultaneously. The
Harrington rods and the Roy-Camille
plates were used for a very long
period, then we started to use
progressively rigid systems like CD
and SCS for trauma reduction and
fixation.
This development in spine surgery
was accompanied by the inauguration
of a center for functional
rehabilitation for patients with spine
trauma. At the same time, an
instrumentation center was also built,
near the Orthopedics Center.
These medical and paramedical
structures multiplied in Tunis -
Children Hospital, Charless Nicolle
Hospital, Aziza Othmana Hospital - as
well as in Souse, Sfax, Monastir and
Nabeul in order to address an
increasing need for all patients
around the country. Soon after,
Tunisia faced a rapid development of
28 ARGOS SpineNews N° 6- September 2002
Spine surgery
at Tunis :
STATE OF THE ART
Spine surgery started to
develop in Tunisia in the early
70’s when the Orthopedics
Center of Kassar Said was
built under the direction of Pr
M T Kassab. This center was a
direct consequence of a strong
collaboration between Tunisia,
USA, Canada and France.
degenerative spine surgery. The
degenerative pathologies are
expanding nowadays, but for quite a
long time patients with degenerative
spine were addressed directly to
neurosurgeons. It is only after several
years that degenerative spine started
being treated by orthopedists and has
now an important place in their
practice. For the last 15 years, we
have noticed an increase of the
number of patients suffering from
degenerative diseases in general and
more particularly spine degenerative
diseases, i.e. cervical arthrosic
myelopathy, spondylolisthesis,
lumbar scoliosis and lumbar stenosis.
This increase is mainly due to the
improvement of the life quality,
thereby the increase of life
expectancy of patients, requiring
more and more autonomy. The
treatment of spine degenerative
pathologies benefits nowadays of the
important progress in medical
imaging techniques, as well as in the
anesthesia-reanimation and in spinal
instrumentation. This is why after a
long period when spine surgery was
limited to decompression, we have
evolved, in parallel to the French
school, towards a better
comprehension of the
physiopathology, of biomechanics and
of the medical management of
patients. The fixation techniques as
well as the use of grafts are now
routine practices. The
instrumentations we use also evolved
and we privilege the semi-rigid
instrumentations, TWINFLEX type,
which proved to give satisfactory
results. This evolution was possible
due to permanent contacts and
exchange with the pioneers in this
kind of surgery, such as Dr Ch Mazel,
who taught several medical school
students from Tunis, Pr Senegas, Pr
Steib, Pr Onimus and many others.
Thus the spinal surgery for
degenerative pathologies but also for
trauma and deformities is now
practiced in a modern environment in
different university hospitals but also
in private healthcare centers. Last but
not least, the Tunisian social security
system, which now refunds all
medical imaging examinations (MRI,
CT, myelography etc) as well as the
osteosynthesis materials for all
patients, had a tremendous impact on
the development of spine surgery in
our country. ■
– Doctor Mongi Miladi

Evaluation Massive disc herniation
This prospective study
analyzed the results of
treatment in patients with
massive lumbar disc extrusions
at L4 - L5 level treated
surgically with three different
procedures. The goal was to
determine whether the
addition of transpedicular
instrumented or interbody
cage fusion improves the
clinical outcome in patients
undergoing decompressive
laminectomy.
30 ARGOS SpineNews N° 6- September 2002
SECOND POSTER PRESENTATION
AWARD - ARGOS SYMPOSIUM 2002
Massive
disc herniation
at L4-L5 level
– Fokter Samo K. and Vengust V
Department for orthopaedic surgery
Celje general hospital, Oblakova 5, 3000 Celje SLOVENIA
Materials and methods :
Fifteen patients who had symptomatic
acute massive disc herniation were
prospectively studied with a followup
of at least 2 years. All patients
underwent herniotomy with posterior
decompression as necessary. Patients
were randomized to a group, where
no additional procedure was
undertaken (Group A, 5 patients),
posterolateral fusion group with
transpedicular instrumentation
(Group B, 5 patients), and interbody
fusion group with cylinder titanium
cages (Group C, 5 patients). At final
follow-up the patients were asked to
fill-in the Oswestry questionnaire.
Clinical and radiological evaluation
was performed using scoring system
of the Japanese Orthopaedic
Association and score after Tria.

Evaluation Massive disc herniation
Results :
Overall, the clinical outcome was
excellent or good in 11 (73,3%) of
patients. There was one patient
graded fair in Groups B and C
respectively. In Group A one patient
was graded fair and one poor. The
patient graded poor required revision
surgery one year after index
procedure.
Conclusion :
Despite the groups were to small for
statistical analysis, the results of the
study suggest that patients
undergoing surgical treatment for
massive disc herniation at L4-L5 level
may do better if being fused at the
time of primary procedure.
References
1 Faibank JCT, Couper J, Davies
JB, O’Brien JP : The Oswestry
low back pain questionnaire.
Physiotherapy 1980; 66:271-3
2 Tokuhashy Y, Satoh K, Funami
S :
A quantitative evaluation of
the sensory dysfunction in
lumbosacral radiculopathy.
Spine 1991; 16:1321-8
3 Tria AJ, William JM, Harwood
D,
Zawadsky JP : Laminectomy
with and without spinal
fusion.
Clin Orthop 1987; 224:134-7
September 2002 - N° 6 ARGOS SpineNews 31

Dr Eric T. Jones
Dr Eric T. Jones did his medical school
training and also did research for his
PhD(Biochemistry) at the University of
Michigan. He also did his orthopedic training
there. He worked at the Mott Children’s
Hospital in Ann Arbor for 2 years prior to
moving to West Virginia in 1980. He is
currently Clinical Professor of Orthopedic
Surgery at West Virginia University where he
does Pediatric orthopedics and spine surgery.
He is a member of the Scoliosis and the
Cervical Spine Research Societies, the
Orthopedic Research Society, the Pediatric
Orthopedic Society in addition to ARGOS. He
is an editor for the Journal of Pediatric
Orthopedics and a consulting editor for the
Journal of Bone and Joint Surgery.
“As president of ARGOS-NA I hope that
we can provide a forum of free discussion
regarding the care and treatment of
spinal deformity and disease. We hope to
remain a relatively small group so that
those interested in spinal osteosynthesis
can meet together and discuss innovative
ideas and problem areas in an
atmosphere of an intimate group. Many
outlets are already available to present
results of large numbers of patients with
long-term follow-up. Usually by the time
these are collated and presented, the
methods are outdated and of historical
interest. ARGOS-NA will provide a
meeting atmosphere to bring new ideas
at an early stage of development to hear
criticism from their peers. The format of
the meeting will be similar to ARGOS,
with one main topic, however we will
also have small break-out group sessions
to continue to foster exchange of new
ideas in spinal deformity, cervical spine
disease, lumbar spine disease and spinal
osteosynthesis data collection. We think
ARGOS-NA along with ARGOS could be
a major contributor to collection and
sharing of spinal osteosynthesis data and
outcomes.”
32 ARGOS SpineNews N° 6- September 2002
First Argos North America confere
Breaking the
The inaugural meeting
of the newly founded ARGOS North America
Association was held at Nemacolin Woodlands
Resort and Spa, in Maryland, USA, from August
2nd to 3rd. About 40 participants gathered
around a fruitful discussion on a four session
scientific program.
Session 1 :
“In Situ contouring”
Pr Jean Paul Steib, Strasbourg, France
and Pr Eric T. Jones, Morgantown,
West Virginia, confronted their
experience with in situ contouring,
long follow-up versus medium followup.
Pr Steib, who is the conceptor of
the SCS instrumentation for scoliosis
correction by in situ contouring,
mainly dedicated to scoliosis
correction, but also applicable to
trauma, degenerative and tumor
surgical treatment, started his lecture
by presenting the philosophy of the
technique. He reminded that it is a
step by step procedure, allowing for
the separation of the corrective step
from the implant and rod insertion
step. The in situ contouring consists
in level by level and plane by plane
corrective maneuvers and the main
advantage in comparison with other
correction techniques comes from the
possibility to stop or to continue the
corrective actions at any moment of
the surgery, depending on the
stiffness of the spine and on the
severity of the deformity. In other
words, as Pr Steib put it, the surgeon
remains the master of the surgery he
is performing and his actions are not
dictated by the implant he is using.
Pr Jones continued the face to face, by
presenting his experience with in situ
contouring, with a medium term
follow-up (3 years) for his patients. He
stressed the importance of the
learning curve, and insisted on the
safety and easiness of this technique
once the surgeon is familiar with the
procedure. The technique is exciting,
said Dr Jones, mainly because the
outcome in terms of correction seems
to be better than in other techniques.
Nevertheless it is important to make
sure that the corrective actions
respect a well defined path, as
indicated by Pr Steib, in order to
avoid excessive stress in the implants
Dr Jones performing a workshop on the in situ
contouring technique.

nce :
frontiers
and to ensure an optimal correction
for each patient.
Session 2
“Lumbar degenerative
diseases”
The first speaker, Dr William R.
Dr William Blake Rodgers
Dr William Blake Rodgers did his B.S. at
the Yale University, New Haven,
Connecticut, in Molecular Biophysics and
Biochemistry and his medical training at
the Harvard Medical School, Boston,
Massachusetts. He was a surgical intern
at the Massachusetts General Hospital,
Department of Surgery, Boston, MA, and
an orthopaedic resident in the Harvard
Combined Residency Program in
Orthopaedic Surgery Massachusetts
General Hospital, Boston, MA. Since 1994,
he was a fellow in the same department
for two years and then a Ober Fellow in
Pediatric Orthopaedic Surgery at Boston
Children’s Hospital. In 1998 he was
certified in the American Board of
Orthopaedic Surgery. Among several
honors and awards, Dr Rodgers was
awarded the Clarence W Mendell and the
Richard Kilfoyle prizes, as well as Yale
University Summa Cum Laude. He is a
member of the American Academy of
Orthopaedic Surgeons, American
Association for the Advancement of
Science, American Medical Association,
European Association of Research Groups
in spinal OSteosynthesis (ARGOS), North
American Spine Society and other
prestigious societies and associations. He
is also the Vice-Chair of the Yale
University Development Board, ARGOS of
North America and Department of Surgery
St. Mary’s Health Center.
Zerick, Columbus, Ohio, presented
different scenarios for degenerative
lumbar pathologies, on various cases.
He emphasized that from the
neurosurgeon’s point of view, the goal
of the surgery remains the
decompression of the nerve roots in
patients suffering from back pain.
Then the stabilization of the spine by
arthrodesis may be performed by
different approaches. In his practice
“I think that all of those I’ve seen that
have been involved in the early stages
of ARGOS North America had the
opportunity to attend and participate
in the ARGOS Europe experience.
Some of us had the opportunity to go
further and see some of the things that
are growing up in Asia as related to
ARGOS and it has been rewarding
and enlightening to be involved in
what Dr Mazel, Pr Kehr, Pr Steib have
built. Those of us who have been to the
ARGOS Europe hope that we will be
able to bring the spirit, if not the
format, to North America. We very
much want the organization to be as
small and as fraternal and collegial as
ARGOS Europe. We also very much
like that the meeting be as open and as
free spirit. One of the great strengths
of the European meeting is the give
and take between the podium and the
audience that is uncommon in larger
North American meetings. The other
opportunities that we see for North
America are for the multicenter
studies among those of us involved,
and for cooperation between groups
around the country. One of the divides
in spine surgery in North America is
the divide between orthopedics and
neurosurgery. We are very interested
in this group in making sure that
everyone is welcome and that
everyone is involved. I am
orthopedics, Dr Zerick is
neurosurgeon, and we all want to be
certain that all sides of the issue are
he had a bad experience with cages
and therefore he recommends the
posterior arthrodesis with interbody
grafts which gives a higher rate of
fusion and a much better general
outcome for the patients.
Nevertheless, he concluded that the
selection of patients is still the main
difficulty in back pain surgery as well
as the patient matching to the surgery.
The arthrodesis is, in his opinion a
heard and that no one feels left out or
left behind.
The other thing we have learned from
Pr Steib, Pr Kehr, Dr Mazel has been
the idea of smaller groups that give
this familiar nature of the ARGOS.
ARGOS Europe has the advantage of
Paris, which North America does not
have. But we have the advantage of
size, which is a great strength. We are
hopeful that, over the course of time,
the membership will expand and
include all the North America, not just
the United States, including Canada,
Mexico, Central America. All people
that are interested in spine surgery are
welcome. The main reason behind
starting this organization is to make it
a small group of friends, rather than a
large multi room, multi day, multi
experience meeting that tends to
overwhelm the individual. We would
like to create here, just like it has been
done in Europe, a smaller group of
friends having similar experience and
willing to share it. All are welcome, all
are encouraged to participate.”
September 2002 - N° 6 ARGOS SpineNews 33

Dr Melvin D. Law
Dr Melvin D. Law did his medical school
training at the Medical College of Virginia,
Richmond, and got his B.S. degree in
Chemistry at the Virginia Commonwealth
University, Richmond. He did his internship in
general surgery, then his residency in
Orthopedic surgery and became a chief
resident at the University of Tennessee
College of Medicine, Chattanooga Unit.
Erlanger Medical Center. He was a Hogan
Spine Fellow at the Beth Israel Hospital
(Harvard Medical School) and did a
Fellowship in Trauma and Spine at the
Harborview Medical Center (University of
Washington). He is a member of the North
America Spine Society, the American
Academy of Orthopaedic Surgeons,
Nashville Academy of Medicine, Tennessee
Orthopaedic and J. Robert Gladden
Orthopaedic Societies. He is also a journal
reviewer for Spine (Chairman of the Spine
Review Committee since 2001) and board
member of ARGOS North America,
Centennial Medical Center Board of Trustees,
Nursing Resource Solutions and Premier
Orthopaedics and Sports Medicine PLC.
“I feel that ARGOS North America will be
the premier society for allowing
interactive surgeon participation in
discussions of topics of interest, new
ideas, case reports, controversies and
research related to spinal disorders.
Because of the small size of the group at
the meeting, all of those who attend the
ARGOS meeting will have a venue very
different from the large society meetings
where far more in depth discussions can
occur related to the topics presented. The
diverse group making up the ARGOS
board and the close relationship with
ARGOS Europe will provide a very
interesting and diverse basis for many
discussions and presentations.”
34 ARGOS SpineNews N° 6- September 2002
good option for discogenic pain and
facet pain, and he recommends
discography and MRI examination in
order to identify the type of pain, i.e.
discogenic or facet pain. He also
mentioned the need of a classification
for degenerative disc and/or
degenerative joint in order to
objectively evaluate which patients are
appropriate for surgery indications.
Further on, Pr Adnan A Abla,
Pittsburgh, Pennsylvania, made a
lecture on the incidence of the
pedicle screw failure in the lumbar
spine fusion and showed several cases
of pedicle breakage as well as of rod
slippage. The patients were surgically
treated for mainly degenerative
pathologies, i.e. spondylolisthesis,
type II and type III isthmic
spondylolisthesis, degenerative disc,
axial and discogenic low back pain,
lumbar stenosis. His explanation on
this frequent phenomenon stands in
the excessive forces applied on the
implant post-operatively.
Nevertheless, he confronted these
results with his previous experience
and concluded that the failure rate
related to screw breakage, rod
slippage or implant pull out is
significantly reduced, probably due to
better adapted diameters of the
screws.
A new surgical technique was
presented by Dr Kee B. Park, Cape
Girardeau, Missouri, the paramedian
Doctor Melvin Law and his wife at the Gala dinner.
approach for pedicle screw fixation.
The technique consists in minimizing
the incision by using fluoroscopic
localization, muscle splitting exposure
followed by fluoroscopic pedicle
screw insertion and finally
intratransverse fusion.
Faced to an increasing number of
indications for fusion, Dr Park
adopted this technique in order to
perform a minimally invasive surgery,
for patients with previously failed
lumbar interbody fusion. His results
show that the technique is a safe and
effective way of achieving posterior
arthrodesis with minimal muscle
destruction. Nevertheless, he only
recommends it for indications where
pedicle screw insertion is needed but
intradiscal and access is not required.
A particularly interesting study was
presented by Dr William Blake
Rodgers, Jefferson City, Missouri, on
the clinical outcomes of lumbar fusion
in morbidly obese patients. Dr
Rodgers operated 144 obese patients,
out of which 43 were morbidly obese
(>40% above the ideal body weight).
He pointed out the difficulty of such
surgery and made some useful
recommendations for surgeons who
would face similar situations, such as
specific positioning of the patient in
order to avoid risks of neuropathy. As
for the surgical technique itself, Dr
Rodgers suggested the use of large
diameter screws (7, 8, 9 mm) and

sacral fixation. Post-operatively, the
patients should be mobilized early to
avoid pneumonia and antibiotic
prophylaxis should be considered as
well as local antibiotics in order to
prevent from infection, which is more
frequent in the obese patients than in
the general population. Nevertheless,
his study showed that the lumbar
fusion in morbidly obese patients is
technically feasible and he found no
significant difference in complication
risks between morbidly obese and
simply obese patients. In these cases
too, the selection of patients is of
paramount importance for the success
of the surgery.
Session 3 :
“Guest Lectures”
The first guest lecture was given by
Raphael Dumas, who is a PhD
candidate at the Laboratoire de
Biomécanique, ENSAM, Paris,
France, whose work focuses on the
three dimensional assessment and
simulation of the surgical correction
of scoliosis by the in situ contouring
technique. His study is conducted in
collaboration with Pr Jean Paul Steib
and is based on the simulation
techniques previously developed at
the LBM-ENSAM Paris, as well as on
imaging processing techniques
developed in collaboration with the
Laboratoire de Recherche en
Imagerie et Orthopaedie (LIO) of the
École de Technologie Supérieure of
Montreal, Canada.
This biomechanical analysis of the
surgical correction by in situ
contouring relies on innovating
methods of three-dimensional
reconstruction of the spinal column
(by a method of stereoradiography)
and on the numerical simulation of
the surgical maneuvers (by finite
elements).
To date, twenty patients were able to
be analyzed in three-dimensions,
demonstrating a correction of the
scoliosis in the three planes of the
Professor Pierre Kehr with Professor Jean-Paul Steib at the Gala dinner.
Dr William R. Zerick
Dr William R. Zerick obtained his
Undergraduate Degree at the West
Virginia University in 1983 (BA
Chemistry) and his Medical Degree in
1988. He did his internship in
General Surgery at Charleston Area
Medical Center from 1988 to 1989 and
his residency in Neurological Surgery at
The Ohio State University from 1990 to
1994. He was a Fellow at Barrow
Neurological Institute, Phoenix Arizona
for 6 months in Spinal Surgery. He is
currently in private practice in an 11
man neurosurgical group in Columbus
Ohio.
Dr Zerick in the author or co-author of
5 papers and 3 book chapters.
He is the winner of the Resident of the
year, Neurological surgery, Ohio State
Neurosurgery Society, 1993 and the
Resident of the year, Columbus
Childrens Hospital 1990.
He is currently Medical Director Spinal
Surgery, Human Motion Institute,
Riverside Methodist Hospital Columbus
Ohio.
“Personally, I see the advantage of
having a North America ARGOS
being that we get to share in a world
wide view what is going on in the
Training First Argos North America conference
spine surgery as well as, I hope, to
spread world wide clinical trials. I
think that, unfortunately, sometimes
we fall into this trap of being trained
to certain practice and that we are
“married” to it and think that we are
grown-up, that our experience is the
right one. We’ve got national
meetings that are great meetings but
I think that my understanding of
how ARGOS works in the meetings
is that it is really a very unique form
to share information and philosophy
on a different scale, on a different
level, on an international scale. The
exchange of ideas in a very free
spirit is one of the greatest strengths
of ARGOS. So I think that this is the
main advantage to have ARGOS
North America adopting a similar
form and a similar spirit.”
September 2002 - N° 6 ARGOS SpineNews 35

Training First Argos North America conference
space. In particular, the axial rotation
of the apical vertebrae (the most
deviated) is corrected at 60%, while
the inter-vertebral axial rotation is
corrected at 78% at the level of the
end vertebrae of the curve (where it
reaches its maximum). For some of
these patients, the personalized
numerical simulation of the surgical
gesture has been realized and has
shown a progressive correction of the
scoliosis in the three planes of the
space. The research tools developed
in this project have been put at the
surgeon’s service so that he be able to
analyze and evaluate his surgical
technique.
Alexandre Templier, PhD, Paris,
France, is the general manager of
SurgiView, a French company
specialized in computer assisted
clinical research tools. He started his
lecture by reminding the main steps
in computer assisted surgery, starting
from the 80’s when stereotaxy was
first used in neurosurgery. Ever since,
the applications of computer sciences
in surgery are continuously
developing and computer assisted
pedicle screwing is one of the most
used tool in computer guided surgery
for the spine, in order to have a
precise positioning of the screws right
in the middle of the pedicle to avoid
neurological complications. All along
his lecture, Mr Templier pointed out
that even though the problem of
accurate positioning seems to be
solved, the surgeon faces another
important challenge nowadays, as he
does not know which is the optimal
fixation he should perform for a given
patient. In other words, the screws
are accurately placed to fix the spine
segment in a given position, but this
given position is arbitrary. Therefore,
before obtaining the optimum 3D
positioning of orthopaedic implants,
the real challenge for the next decade
will consist in defining this optimum
position with regard to the whole
posture and motion of patients. This
challenge will be taken up by
motivated practitioners involved in
cooperative prospective clinical
research, using appropriate tools to
36 ARGOS SpineNews N° 6- September 2002
save time and gain efficiency. In Mr
Templier’s opinion, the main key
points of clinical research processes
that will be drastically improved by
computer technology are clinical data
harvesting, measurements accuracy
and reproducibility, data sampling &
analysis, and statistical significance.
Calculation power was the first
revolution brought by computers. The
second one is Network connectivity,
opening large-scale data & resources
sharing possibilities. Computer
assisted clinical research will
undoubtedly be cooperative, thus
providing high statistical significance,
and allowing for experience sharing
among practitioners, for the ultimate
benefit of their patients.
Pr Pierre Kehr, Strasbourg, France
gave a magisterial lecture on the
different approaches to the lower
cervical spine: decompression, fusion
and disc prosthesis. These three
approaches are used either to act on
the discs and on the vertebral body by
antero-median approach in order to
enlarge the vertebral canal and the
vertebral foramen either by
transdiscal approach or by
corpectomy, or to free the vertebral
artery by antero-lateral approach.
Before citing the advantages and
drawbacks of each technique, Dr
Kehr recommended special care with
the delicate anatomy of this region,
mainly concerning the thyroid artery,
laryngeal, glossopharyngeal and facial
nerves, stellar ganglion… As for the
advantages of each technique, the
cage and plate or coral grafting is a a
very easy to perform approach, while
the corpectomy with coral or fibula
graft gives an excellent view of the
canal. The iliac bone graft and
osteosynthesis presents the advantage
of autologous graft. Finally the disc
prosthesis allows for preservation of
the motion and of the adjacent levels,
but the selection of the patients is
once again essential for a good
outcome. On the other hand, the main
drawbacks of arthrodesis, either by
cage and plate or by grafting and
osteosynthesis, is the loss of mobility
and the degeneration of the adjacent
levels, while the disc prosthesis
presents some risks of kyphotic block
and of secondary ossifications in some
cases.
Finally, Dr William Blake Rodgers
shared once again his experience by
presenting the outcomes of the
anterior cervical fusion. His study
focused mainly on the use of allograft
composites and on the cervical plate
evolution. The allografts were used in
order to improve the fusion rate in
anterior multilevel cervical plating, as
fusion non-unions are quite frequent
in cervical fusion with autograft
(reported pseudarthrosis rates of
about 40%). His study outlined that
the use of composites with cervical
plating presents no technical
problems and that there was no loss of
lordosis post-operatively. In spite of
some plate design modifications that
are needed to improve the chances of
fusion, Dr Rodgers concluded that a
combination of endplate burring,
allograft demineralised bone matrix
composite and dynamic anterior
plating have a very satisfactory
outcome in anterior cervical
multilevel fusion.
The scientific sessions were followed
by Pr Jones’ closing remarks. He
encouraged participants to give their
feed-back with regard to the form of
this meeting, as well as its scientific
content. He also mentioned that
Nemacolin Woodlands seems to be a
perfect location for the ARGOS North
America Meetings, perfectly
matching the friendly spirit of the
discussions and favoring collegial
debates. He expressed his wish to
welcome the participants next year, to
the next ARGOS North America
Meeting. ■
– Anca Mitulescu

Training 18th annual CSRS-ES meeting
18th annual meeting of the CSRS European section
Multidisciplinary
approaches to the
cervical spine
The 18th Annual Meeting of the
CSRS European Section was
held June 13-14 in Paris at the
Meridien Montparnasse Hotel.
More than 300 participants
convened to discuss several
aspects related to
multidisciplinary approaches
to the cervical spine. The
opulent surroundings and
collegial atmosphere belied the
vigorous and rigorous dialogue
on a variety of topics such as
modern analysis and
evaluation techniques, surgical
approaches, minimally
invasive surgery and
preservation of motion in the
cervical spine. The scientific
sessions and round tables
brought together a remarkable
panel of well known
orthopaedic surgeons,
neurosurgeons,
neurophysiologists, and neuroanatomists
as well as
biomechanics specialists from
all over the world.
THE PRESIDENT of the CSRS-
ES, also organizer of the 18th
Annual Meeting, Dr Christian Mazel,
from the Institut Mutualiste
Montsouris in Paris, welcomed the
participants and reminded the strong
link between the European section
and the US one. Indeed Cervical
Spine Society, with its two sections -
US and European - is a unique society
and reciprocal invitation of respective
section president to each meeting is a
38 ARGOS SpineNews N° 6- September 2002
From left to right : Doctor Mazel, Pr Itoh., Pr Crockard.
most efficient way of reinforcing
exchanges over the Atlantic towards a
better collaboration and a continuous
increase of the scientific level of the
society activities.
Surgical approaches in cervical
spine
During the first round table, Dr B
George (Paris, France) presented two
different approaches meant to expose
the vertebral artery at the craniocervical
junction : the posterolateral
approach consists in fully exposing
the posterior arch of the atlas, by a
lateral enlargement of the standard
midline approach. It is mainly
indicated for intradural tumors at the
foramen magnum level and for some
extradural and posterolateral lesions.
The anterolateral approach consists in
opening the field between the
sternomastoïd muscle and the internal
jugular vein, followed by a dissection
of the accessory nerve and the
exposure of C1 and C2 transverse
processes. This approach is essentially
used for extradural lesions.
Pr P Kehr (Strasbourg, France)
reminded that, whatever the
approach, the aim of the surgery is to
free the vertebral artery. He then
made a brief anatomical reminding to
better define the “unco-arterioradicular
crossroads”, located
between the cervical transverse
processes. The anatomy around the
vertebral artery is very delicate, as the

path of the artery is extremely tight.
Therefore, Dr Kehr explained the
mechanisms of arthrosis or posttraumatic
lesions that will result in
vertebral artery deviation and/or
compression, mainly dynamic, which
will be responsive for blood flow
troubles.
Furthermore, Dr R Robert (Nantes,
France) described some anatomical
aspects of cervicalgia, in comparison
with lumbalgia. His studies indicate
that the neurological distribution of
the somatic and sympathetic systems
are similar in the cervical and lumbar
regions.
Faced to the serious complications
associated with anterior transcervical
approaches in tumours, such as severe
deformities, post-operative alteration of
shoulder mobility and cervical posture,
Dr D Gunenwald (Paris, France)
developed a new transmanubrial
technique that avoids muscular section
and respects the scapular girdle
articulations. As described by Dr
Grunenwald, this new technique
allows for a good control of the
subclavian vessels and the brachial
plexus as well as a sufficient exposure of
the anterior part of the cervicothoracic
spine. He then presented the technical
aspects of this new approach.
Polyarthritis in cervical spine
A very interesting study was
presented by the team of Leiden
University Medical Center,
Netherlands. Dr Peul and his
colleagues performed a comparison of
several fixation techniques in cases of
instability in patients classified as
Ranawat class 3-B, i.e. C1C2 posterior
fixation without spinal cord
decompression, craniocervical
fixation, transoral approach for cord
decompression and dorsal
craniocervical decompression. The
results of their study showed that the
mortality rate according to Crockard
is unacceptably high (40%) in the first
six months after surgery, in
comparison with Ranawat class 2 and
3-A patients (2%). Nevertheless, these
techniques seem safe enough and the
complication rate is low in
experienced hands and are justified if
craniocervical pathology is
progressive and is associated with
neurological deterioration during
follow-up. Given this controversial
situation, Dr Peul and his team
suggested that a randomised clinical
trial be set up in order to evaluate the
real effectiveness of these surgeries.
Furthermore he described the main
evaluation indexes to be taken into
account in the clinical trial.
Minimally invasive techniques
Dr T Shiraishi (Japan) presented a
new technique based on interlaminar
decompression for cervical
spondylotic myelopathy, that
consisted in decompressing the spinal
cord by removing the cephalad half of
the laminae and of ligamenta flava.
This technique allows for the
preservation as a unit of the
continuity from the posterior arches
to the semispinalis cervicis and
multifidus muscles. The procedure
was compared to a classical open-door
laminoplasty and the results of the
study indicated lower morbidity with
a better preservation of neck motion
and cervical lordosis. Nevertheless,
even though this technique seems to
allow for a less invasive interlaminar
decompression for the posterior
extensor mechanism, further
evaluation should be performed, as
the reported preliminary results were
obtained for a small population of 18
myelopathic patients (minimum
follow-up 2 years). Another Japanese
team from Osaka University Graduate
School of Medicine developed a new
en-block laminoplasty procedure
without dissection of paraspinal
muscles in order to avoid
malalignment and segmental
instability, frequently associated with
laminoplasty for cervical myelopathy.
Dr N Hosono presented the technical
aspects of the procedure he
performed on 37 patients up to now
(mean follow-up 27 months), as well
as the evaluation method, based on
radiological and clinical indexes. He
reported good results and concluded
that the technique may avoid
undesirable kyphosis or instability
after surgery because the
paravertebral muscles, which play an
Training 18th annual CSRS-ES meeting
important role in maintaining the
cervical lordosis, are left intact.
New investigation techniques
Once again, the Biomechanics
Laboratory of ENSAM (Paris, France)
proved their mastery in analysis tools
development for the study of the
spine. B Fréchede, PhD presented a
neck model developed by means of an
explicit finite element method. The
geometry of the model includes the
head, C1-T1 vertebrae and discs,
ligaments, soft tissues and muscles,
taking into account the contacts
between articular facets and spinal
processes. Skin was also represented
in the model by membrane elements.
Mechanical features were taken from
the literature as well as from injury
criteria. The model was fully validated
in terms of kynematics and injury
mechanisms. The main advantage of
this model is its potential in injury
mechanisms simulation, yielding
better understanding of the effects of
various constraints and a better posttraumatic
assessment of injuries.
A simultaneous study conducted
by the same team, presented by Pr W
Skalli (Paris, France), investigated the
mechanical properties of human
cervical spine segments by applying
pure moments in order to obtain
load/displacement curves. They
recorded the C5-C6 intervertebral
motions, using a Two Micrometric
Heads device, when pure rotational
moments of 2 Nm of
flexion/extension, bilateral axial
torque and bilateral lateral bending
were applied on C4, for nine cadaver
spines. The results of the study
proved very relevant for the
understanding of the cervical spine
motion and allow for a documentation
of the main and 3D coupled
displacements of cervical spine
segments.
C Chiquet, from the same
laboratory, investigated the possibility
of assessment of cervical motion by
3D ultrasonic tracking system. He
described a protocol implemented in
hospitals that allows for a very precise
analysis of the cervical spine
kinematics. With measurements taken
on a large scale, this study anticipates
September 2002 - N° 6 ARGOS SpineNews 39

Training 18th annual CSRS-ES meeting
the possibility of identifying a specific
signature of the patients after trauma.
This protocol may be used in the
future both for diagnosis purposes
and for evaluation during the clinical
follow-up.
Preservation of motion in cervical
spine
One of the areas of agreement among
participants was the preservation of
motion in cervical spine surgery.
Indeed, the cervical spine plays a
major role in the mobility of the head
and thereby influencing the global
balance of the patient. Thus the
preservation is essential, but the
indications for orthopaedic treatment
or reconstruction surgery should be
carefully weighted in order to avoid
possible complications associated
with instability (neurological
disorders, secondary displacements
etc). Dr D Brinkert (Strasbourg,
France), speaking on behalf of Dr A
Grosse, emphasized the importance
of the indication in reconstruction
preserving motion in cases of the dens
trauma and mal unions. Based on his
experience, the best surgical
technique he would recommend for
unstable dens fractures is axial dens
screwing, as it respects the anatomy
and the physiology of the atlantoaxial-joint,
thereby ensuring
functional rehabilitation, especially
rotational function. He then discussed
the dens non-unions problem,
reminding that non-unions may be
with regular sides or with bone
defect, requiring different
approaches, either axial screwing with
bone graft for the former or the Louis’
transoral approach for the latter, both
methods allowing for the preservation
of motion.
Dr M Ruf (Karlsbad, Germany),
speaking on behalf of Dr J Harms,
Pr Ullrich and his wife and Pr Anderson.
40 ARGOS SpineNews N° 6- September 2002
concurred with Dr Grosse about the
major biomechanical and anatomical
particular features of the occipitocervical
junction, in comparison with
the other spine regions. He considers
that the reconstruction or the fusion
indications should be based on an
exact knowledge of the biomechanics
and anatomy in order to analyze the
different types of fractures and to
decide for the appropriate treatment.
The major difference from other spine
regions is that in the occipito-cervical
junction fractures, the motion can be
preserved in certain cases while in the
rest of the spine fracture treatment
usually leads to stiffening of the spine.
As for the free communications on
this topic, several techniques were
presented:
Dr M Ruf (Karlsbad, Germany)
presented his long term results in 6
patients operated after unstable
Jefferson fractures (C1-C2). His
technique consisted in a transoral
reduction and C1 osteosynthesis that
would make it possible to restore
congruency in the atlanto-occipital
and atlanto-axial joints while
preserving the rotatory mobility in the
C1-C2 joint.
Two most interesting papers focused
on the evaluation of the Bryan system,
the first cervical prosthesis available
nowadays. The first study, presented
by Dr Jan Goffin (Leuven, Belgium)
was conducted through a multi-center
collaboration between 9 surgeons in 7
health care centers in Europe
(Belgium, United Kingdom, France,
Germany, Sweeden, Italy). The
multicenter clinical trial wished to
evaluate the efficiency and the
morbidity associated with this new
device in patients suffering from disc
herniation and spondylotic changes in
C3-C4 and C6-C7 levels, with
radiculopathy and/or myelopathy, in
comparison with standard anterior
cervical decompression and fusion. 97
patients underwent the disc
arthroplasty and were included in the
clinical trial. The evaluation consisted
in comparing pre and post-operative
pain and functional criteria, i.e.
neurological function, range of
motion. The results on 46 patients at 1
year and 10 patients at 2 years follow-
up showed encouraging results in
terms of range of motion, and most of
then (more than 80%) had excellent or
good clinical scores after surgery
(modified ODOM). Nevertheless, the
range of motion measurements
method is not described. Therefore,
the figures obtained should be
analysed with regard to the accuracy
of measurements. Longer follow-up
should provide more reliable results.
A simultaneous evaluation of the
immunologic response of the Bryan
Cervical Disc prosthesis was
performed in a caprine model. The
methods employed and the results of
this study were presented by Dr PA
Anderson (Mercer Island, WA, USA).
11 Nubian goats were included in the
study and they all underwent the
surgical procedure as required in
humans and the results were
compared to 1 baseline control animal
that was sacrificed immediately after
surgery. Survival periods were
defined for 3 different groups at 3, 6
and 12 months post-operative
respectively. Samples of tissues were
harvested and examined in order to
detect any debris migration,
inflammatory reaction, biologic
response to particulates at all organs.
No neurological complication or pain
was observed. Slight signs of debris
migration as well as small number of
particulates present in local tissues
were noted after 6 months, but no
inflammatory reaction was identified.
However, an evaluation on a longer
post-operative period is expected in
order to conclude on the immunologic
security associated with the use of this
device in humans.
Risks associated with cervical
spine surgery
Two lectures were dedicated to the
oesophagus injuries associated with
cervical spine surgery. Dr P Thoreux
(Bobigny, France) made a summary of
literature findings related to
dysphagia and oesophageal
perforation, stating that these
sequelae are often underestimated as
well as their possible consequences.
Dysphagia can be explained by
haematoma, oedema by preoperative
compression of the oesophageal wall,

Pr Korres and Pr Ullrich and their wifes.
infectious process, regional
denervation or adhesion between the
oesophagus, pre-vertebral muscles
and the edge of vertebral body. As for
the oesophageal perforation, it is
probably the most dangerous
complication associated with anterior
cervical spine surgery as it involves
the vital prognosis.
Fortunately, it only occurs very
rarely and is mainly due to
preoperative trauma or delayed one,
related to hardware conflict, or a
consequence of initial trauma. The
investigations to be performed in case
of dysphagia are the sagittal or frontal
X-ray, chest X-ray, oesophography,
oesophagoscopy, CT examination. As
for the attitude to be adopted in order
to prevent these complications
consists in using a rigid tracheal tube
allowing for preoperative location of
the upper respiratory system and of a
modified Cloward cervical retractor,
with smooth teeth on the side of
oesophagus and carotid artery, with a
45° angle between the sharp blades
and the straight perpendicular to help
positioning under the longus colli
muscles. An inspection of the
oesophageal wall before closure is
also mandatory.
In contrast with Dr P Thoreux
findings, Dr B Gayet (Paris, France)
mentioned the results of a French
survey of 270 patients, that show a
mortality of the cervical perforation of
the oesophagus of 18.5%. Moreover,
the oesophageal perforations are the
most severe digestive pathology with
a mortality rate of 45% secondary to
sepsis and particularly to mediastinal
infection or abscess. As diagnosis
detection or pre-therapeutic
assessment, Dr Gayet recommends
barium swallow, endoscopy , CT scan
and, in case of pleural effusion, a
puncture for research of amylasemia,
polymicrobial infection, methylene
blue. Medical treatment with
antibiotics, perfusions etc is
mandatory and exclusive medical
therapy may be sometimes proposed.
As for the surgical treatment of the
perforation, it is limited to
oesophagectomy, local drainage or
suture. Dr Gayet then presented the
details of the surgical technique of
repair and finished his presentation
by mentioning that cervical drainage
is mandatory as well as CT scan
evaluation of mediastinal lesions and
in some cases a thoracotomy may be
necessary. He concluded by
reminding the mortality rate of this
complication, that can be reduced to 0
only by an aggressive approach.
The future of cervical spine
diagnosis and treatment.
As Dr Anderson explained during his
lecture, the future in cervical spine
diagnosis and treatment will be based
on a better knowledge of both the
anatomy and physiology of the
cervical spine. New findings in
biomechanics as well as new
technological assessments will
redefine the role of the surgeon as
well as the skills he will have to
acquire.
Thus, the diagnosis in spine
surgery will be based on investigation
methods allowing for a better
understanding of the pathogenesis as
well as the evolution process while
the cervical spine surgery will
become minimally invasive, providing
neural protection thereby allowing for
a better neural regeneration and will
probably be often delivered
percutaneously. Furthermore, given
the new developments towards
arthroplasty, the cervical spine
surgery will be oriented more and
more towards the preservation of
motion, the indications for fusion
being left for severe cases of
instability. ■
– Anca Mitulescu & Christian Mazel
Mario Boni Award
Two winners, one for oral communication, one for poster presentation,
were awarded this year:
With 122 votes, the winner for the Best Oral
Communication Award is Dr Ernst SIM et al. (Wien,
Austria) for the communication about “Atlanto-axial
rotatory subluxation in children. A clinical and postmortem
study”.
Authors : SIM E., SCHWARZ N., LENZ M.,
BERZLANOVICH A.
Training 18th annual CSRS-ES meeting
With 117 votes, the winner for Best Poster Award is Dr
Tateru SHIRAISHI et al. (Tochigi, Japan) for the poster
about : “Technique for muscle-preserving laminoplasty
(TEMPL) of the cervical spine to maintain cervical
mobility and stability.”
Authors : SHIRAISHI T., YATO Y., YOSHIDA H., ABE T.
September 2002 - N° 6 ARGOS SpineNews 41

Internet Web review
www.alphaklinik.com
Alpha Klinik is located in Munich,
Germany, and specializes in minimal
invasive knee and spine surgery. They
have made a name around the world
by developing and perfecting minimal
invasive techniques. Their name
symbolizes the first letter in the
Greek alphabet, just as their clinic
wishes to symbolize the first in
experience, technology and a
progressive attitude towards surgery
of the Knee and Back.
www.artificialdisc.com
This website is designed to educate
both physicians and the general
public about the new, revolutionary
technologies for replacing human
spinal discs with artificial discs.
Although fellowship trained in Spinal
42 ARGOS SpineNews N° 6- September 2002
Web review
Orthopedic surgery appears on the internet in a variety of contexts
ranging from academic institutional websites and websites for
commercial ventures to personal webpages for individual surgeons.
Educational material and product information is now avalaible around
the clock.
Surgery, Dr Rolando Garcia (Florida),
Editor, emphasizes the role of
prevention and non-operative care of
most spinal conditions.
www.spinalneurosurgery.com
Spinalneurosurgery.com is a website
dedicated to the surgical management
of patients with spinal disorders. This
website has been created by Associate
Professor Lali Sekhon, a spinal
neurosurgeon*. Dr Sekhon is an
Australian neurosurgeon with special
interests in all manner of spinal
conditions.
This website is for patients
contemplating surgery, or recovering
from surgery. It is also for
professionals who may wish to refer
complex spinal cases from throughout
the world.
www.spineuniverse.com
SpineUniverse is dedicated to the
mission of being the most
comprehensive Internet portal for
information on the spine. They seek to
educate the public to the full range of
technologies, services, treatments and
research available on the subject of
spinal disorders.
Their fundamental goal is to marry
the best minds and the best
companies into a dedicated portal that
fulfills our prime objective to educate
the public. SpineUniverse is a
collaborative effort of medical
professionals to serve the community
of individuals suffering from back
pain. SpineUniverse came into being
with the initial support and
investment of spine specialists and
medical companies around the
country. The new International Board
brings together more spine specialists
from around the world.
www.bioeng.ucsd.edu
Bioengineering was established at
UCSD in 1966, just after the founding
of the campus, and has been
graduating BS and PhD students
since the early 70’s. Bioengineering
was originally associated with the
department of Applied Mechanics

and Engineering Science, but in 1994
became independent department. At
present, there are 13 core faculty, 20
post doctoral fellows, 30 research
faculty and affiliates, and many
collaborating faculty from other
departments that participate in
instructional activities. There are
presently over 100 undergraduates in
each class completing degrees in
bioengineering, premedical, and
biotechnology majors, with a new
undergraduate major in
bioinformatics recently inaugurated.
At the graduate level, there are
presently over 40 students working
toward Master of Science (MS) and
Master of Engineering (MEng)
degrees and over 70 students
pursuing PhD and combined
MD/PhD degrees. There is also a new
interdisciplinary PhD program in
bioinformatics within the department,
involving faculty from chemistry,
biology, physics, math and computer
science.
UCSD graduates in Bioengineering
are currently employed in a variety of
positions in education, medical,
industrial and governmental service
at local and national levels.
www.spinearthroplasty.org
The Spine Arthroplasty Society is a
special interest group of medical and
associated specialists devoted to the
field of clinical and structural
amelioration and restoration of the
joints of the spinal column. The
Society’s focus is on restoration, or
replacement and potential return to
normal function lost by degenerative
conditions of spinal joints, especially
where prostheses or orthoses may be
required to accomplish these goals.
While spine fusion may be the most
widespread option for treating low
back pain conditions today, in the near
future, the options associated with
Spine Arthroplasty will be available
alternatives in treating spinal
problems. The Spine Arthroplasty
Society (SAS) was established on this
platform and the society’s focus will
be on all advances in spinal treatment
with a baseline credo of promoting
“the science” and not “the product”.
The society’s goal will be to promote
the ethical exchange of knowledge,
research and education to restore
function and comfort to degenerative
conditions of spinal joints, especially
the intervertebral disc. The Society
will advance the philosophy of natural
spinal mobility through dissemination
of educational materials to spinal
surgeons, the medical community and
the lay public.
Reflecting globalization, the society
will not be ‘’regionalized” but be a
contemporary and open forum for
educating specialists throughout the
world. Reflecting on the availability of
the Internet as a communications
resource the Society will extensively
use its web site in addition to staging
of more traditional meetings and
publications.
www.memced.org
The Maurice E. Müller Center for
Continuing Education and
Documentation (MEM-CED) was
established in 1974, for the purpose of
advancing the field of orthopaedic
surgery by education, documentation
and evaluation. MEM-CED is a noncommercial
non-profit branch of the
Maurice E. Müller Foundation. It is
the center’s philosophy that each of
these components is crucial to its
overall mission of contributing to the
national and international
improvement and maintenance of
quality orthopaedic care.
www.neurosurgery.org
Founded in 1931 as the Harvey
Cushing Society, the American
Association of Neurological Surgeons
(AANS) is a scientific and educational
association with nearly 5,500
members worldwide. The AANS is
dedicated to advancing the specialty
of neurological surgery in order to
provide the highest quality of
neurosurgical care to the public. All
Active members of the AANS are
Board-certified by the American
Board of Neurological Surgery.
Neurological surgery is the medical
specialty concerned with the
prevention, diagnosis, treatment and
rehabilitation of disorders that affect
the spinal column, spinal cord, brain,
nervous system and peripheral
nerves. The AANS is dedicated to
advancing the specialty of
neurological surgery in order to
provide the highest quality of
neurosurgical care to the public.
… and don’t forget to connect to
the Argos website
Web review Web review
September 2002 - N° 6 ARGOS SpineNews 43

Evaluation Disc prostheses and arthrodesis
Disc prostheses and
arthrodesis in
degenerative disease
of lumbar spine
The National Agency for Accreditation
and Evaluation in Health (ANAES)
Medicine today is seeing very
rapid development of new
technologies for the
prevention, treatment and
diagnosis of disease. Decisionmakers
in the health service
and health care professionals
have to make choices and
define strategies on the basis
of criteria of safety, efficacy
and benefit. The National
Agency for Accreditation and
Evaluation in Health (ANAES)
evaluates these various
strategies, produces a
summary of available
information and disseminates
its conclusions to all partners
involved in health care. Its role
is to provide assistance with
the individual and collective
decision-making process :
- it keeps the public authorities
informed of the state of
scientific knowledge, its
implications for medicine,
organisation and financing,
and its impact on matters of
public health,
- it helps health care
establishments provide the
best response to patients’
needs in order to improve
health care,
- it helps health professionals
define and implement the
best strategies for diagnosis
44 ARGOS SpineNews N° 6- September 2002
and treatment, in conformity
with the criteria to be met.
This document fulfils this
mission. The information it
contains has been
independently produced using
rigorous scientific methods.
The information comes from a
review of the international
literature and from
consultation with experts.
– Professor Yves MATILLON
Executive Director
The full report (French and English)
is available from ANAES
Service communication & diffusion
159, rue Nationale
75640 Paris Cedex 13
The positions and recommendations
expressed in this document are those
of ANAES and none of the experts
consulted is regarded as individually
responsible for them.
THE TECHNIQUES used to treat
degenerative lesions of the lumbar
spine aim to free compressed nerve
structures and to provide stability.
Three types of stabilisation technique
are used : (1) lumbar arthrodesis,
which is designed to eliminate all
movement between two or more
vertebrae, (2) artificial discs, which
are designed to re-establish disc
function while preserving mobility,
(3) ligament replacements, which are
not dealt with in this report and
about which very few data have been
published. This evaluation was
concerned with the efficacy of the
arthrodesis and disc prosthesis
techniques. The available literature
does not compare the two
techniques. The purpose of lumbar
arthrodesis is to join two or more
lumbar vertebrae. The procedure
sacrifices the function of the
intervertebral disc. The procedure is
performed for various forms of
lumbar spine disease or lesions. This
evaluation was concerned with
degenerative disease of the lumbar
spine, which includes :
- the following degenerative lesions
: disc degeneration, degenerative
spondylolisthesis, degenerative
lumbar scoliosis, lumbar stenosis
and lumbar instability without
spondylolisthesis;
- failure of previous procedures
(i.e. nucleolysis, surgical
discectomy, spinal canal

decompression, or previous
arthrodesis).
Many techniques have been
developed to fuse two vertebrae; they
differ in the surgical approach used,
the site of the bone graft, the type of
bone graft, and whether or not
internal fixation is used. Depending
on the disease or lesion concerned,
arthrodesis may be performed alone
or combined with procedures for
releasing nerve structures. In
contrast, the purpose of an artificial
disc is to preserve mobility between
two vertebral bodies by replacing the
disc. Several types of prosthesis, using
metal and/or polymers, have been
developed but, in practice, only one
model is used at the present time. It is
not known how often either of these
procedures is performed in France. In
epidemiological terms, chronic low
back pain, to which many studies have
been devoted, remains the best
known of the diseases for which these
procedures are used. Scandinavian
studies have estimated the prevalence
of low back pain to be 60-65% over a
lifetime. French data are fragmentary.
In a report published in 1994, the
French Public Health Committee
(Haut Comité de la Santé Publique)
estimated that 52 out of 1000 visits to
general practitioners concerned
problems with the spine and 36 of
them disc problems (low back pain or
sciatica). There are no
epidemiological data on other
conditions such as lumbar stenosis,
degenerative spondylolisthesis or
repeat procedures because of earlier
failure.
Efficacy of arthrodesis in
degenerative disease of the
lumbar spine
It is difficult to study lumbar
arthrodesis, and the poor design of
available studies means that only
tentative conclusions can be drawn
from a critical review of the literature.
Most studies include different forms
of disease or lesions, generally
grouped under the term of “low back
pain”. This term covers clinical
entities which are probably diverse
and which remain very poorly
defined. The lack of definition is
mainly a result of the difficulty in
relating the symptoms experienced by
the patient to anatomical
abnormalities identified by imaging;
such abnormalities are also very
common in the general population,
although they may not produce
symptoms. This lack of a link between
symptoms and anatomical
abnormalities makes it difficult to
interpret the studies that have been
published. There would seem to be
some evidence that lumbar
arthrodesis is effective in
degenerative spondylolisthesis. None
of the techniques used for arthrodesis
has been shown to be clearly superior
or inferior to any of the others in
terms of clinical efficacy. When low
back pain is associated with nerve
root pain or with a neurogenic
claudication syndrome, and a
standard X-ray reveals no
spondylolisthesis, there is no
evidence in the literature that surgical
treatment which includes both
decompression and arthrodesis is
superior to surgical treatment by
decompression alone. In isolated low
back pain, there is no evidence for the
efficacy of arthrodesis compared with
another form of treatment, which
What is ANAES ?
Evaluation Disc prostheses and arthrodesis
could be either medical or surgical
(particularly disc prostheses).
Similarly, studies have not supplied
specific evidence for or against
arthrodesis in cases where previous
surgery has failed. It is not possible to
compare the various arthrodesis
techniques, which differ in approach,
in the use of fixation systems or the
type of bone graft, since no
randomised controlled trials
comparing approaches or type of bone
graft were found. In posterolateral
arthrodesis, the use of some form of
fixation seems to increase the level of
fusion without significantly modifying
the clinical result. The literature
currently available does not offer any
clear evidence that there are any
advantages in using endoscopic
arthrodesis or minimally invasive
techniques. However, it seems likely
that these techniques may be useful in
the future under certain conditions
and in indications which have yet to
be defined. Overall, lumbar
arthrodesis is not well documented.
Nevertheless, experts consider that,
under certain circumstances which
need to be better defined, this
technique can be of real benefit to
patients.
The National Agency for Accreditation and Evaluation in Health is a
Public Administrative Establishment established by the law of 24 April
1996 reforming the public and private hospital service, and by Decree
no. 97-311 of 7 April 1997. This new agency is continuing and consolidating
the missions of its predecessor ANDEM, and has undertaken new
activities, such as establishing an accreditation procedure in public and
private health care establishments in France.
ANAES’ Executive Director is Professor Yves Matillon, and the Agency
is governed by an Administrative Council. The Scientific Council is divided
into two sections, an Evaluation section and an Accreditation section.
ANAES’ two missions are to establish the state of knowledge
concerning strategies for prevention, diagnosis and treatment of disease,
and to promote improvements in the quality and safety of care, both in
hospitals and in the independent sector.
In response to a formal request from its various partners (authorities, institutions,
professional associations, etc.) or on the initiative of its
Scientific Council, the Agency carries out evaluation studies using the
explicit methods and principles which it has formulated, which are based
on a rigorous analysis of the scientific literature and on the opinion of
health professionals. This work makes it possible for institutions and
health professionals alike to base their decisions on the most objective
information possible.
September 2002 - N° 6 ARGOS SpineNews 45

Evaluation Disc prostheses and arthrodesis
Evaluation of arthrodesis of the
lumbar spine : prospects
The literature thus does not provide
answers to the main question of
whether or not lumbar arthrodesis is
effective in degenerative disease. The
way in which patients who may
benefit from lumbar arthrodesis are
selected by the specialist is therefore
based on a case-by-case analysis of the
patient’s condition and relies on a set
of clinical and radiological criteria. In
addition, there are important
methodological problems in setting
up high-quality therapeutic studies.
There are a number of proposed
lines of development :
1. A long-term three-stage strategy
could be established to ensure better
use of lumbar arthrodesis.
- A first stage might seek to achieve a
better understanding of current
practice. A prospective
observational study in one or more
regions of France could help define
the current indications without
influencing practice in any way.
- In view of the lack of precise
disease frameworks, the working
group suggested that the second
stage might be to use the results of
such an observational study and a
formal consensus-seeking method
(such as RAND) to establish broad
categories of indications for lumbar
arthrodesis. For instance,
differentiating patients with signs of
neurological disorders (nerve root
pain, intermittent claudication)
from patients with isolated
recalcitrant low back pain but no
sign of neurological disorder would
appear to be valid; similarly, it
would seem legitimate to
differentiate patients who have not
undergone any surgical procedure
from patients who have already had
surgery. Recommendations could
be drawn from this consensus.
- The third stage might evaluate the
implementation of
recommendations and their impact
on both medical practice and
efficacy of this form of treatment.
Such a strategy would be ambitious
46 ARGOS SpineNews N° 6- September 2002
and costly, but it would provide
answers to many questions posed by
doctors, users and reimbursing
organisations.
2. A clinical research strategy, in
specific indications, could provide a
rigorous comparison of the
techniques used; such a strategy
could be implemented more rapidly
and probably more easily than the
previous proposal. The two strategies
proposed here are not mutually
exclusive; they are complementary in
their objective of achieving a better
assessment of lumbar arthrodesis,
which remains poorly evaluated
despite the very large number of
publications on the subject and the
fact that the procedure has been in
use for many years.
Evaluation of the efficacy of disc
prostheses
Although some surgeons now have
ten years’ experience, the use of disc
prostheses cannot be regarded as a
routine practice. The use of such
devices needs more careful evaluation
before it becomes widespread. Use of
these prostheses should therefore be
restricted to a small number of
centres which are equipped to carry
out a properly designed clinical study.
These centres should have both the
technical capability to perform the
procedure and the ability to carry out
and monitor a well-designed clinical
study. This would enable a better
quantification of short-term
morbidity, long-term results and
complications, and would help
identify preferred indications. Studies
should ideally be comparative studies
Working group experts
Professor Claude Argenson, spine surgery, Nice;
Dr. Arnaud Blamoutier, spine surgery, Rennes;
Dr. Thierry David, spine surgery, Bois-Bernard;
Professor Alain Deburge, orthopaedic surgery, Clichy;
Dr. Christian Espagno, neurosurgeon, Cornebarrieu;
Professor Claude Manelfe, neuroradiologist, Toulouse;
Dr. Christian Mazel, orthopaedic surgery, Paris;
Professor Gilles Perrin, neurosurgeon, Lyons;
Dr. Denis Rolland, rheumatologist, Bourges;
Professor Jean-Paul Steib, spine surgery, Strasbourg;
Professor Jean-Pierre Valat, rheumatologist, Tours.
carried out over a sufficiently long
period. A comparison could be made
with medical treatment or with
arthrodesis, for which it is also
necessary to define precise
modalities. A follow-up period of 10
years or longer is desirable because of
the potential complications which
may occur in the long term, such as
degradation of fixation material and/or
degradation of components subject to
friction. In addition, it could be useful
to establish a registry for prostheses,
which would record information
concerning patients who have been
fitted with prostheses, date of
implantation and, if appropriate, date
of removal. Simple data such as this
would make it possible to evaluate the
life span of disc prostheses. ■
The literature analysis and report
were produced by Dr. Rémi
Nizard under the supervision of
Dr. Agnès Lepoutre, project
manager. This work was
supervised by Dr. Bertrand Xerri,
Head of the Technology
Assessment Department.
Documentary research was
carried out by Mme. Hélène
Cordier, Head of the
Documentation Department, with
the help of Mlle. Sylvie Lascols.
Secretarial services were
provided by Mlle. Laurence
Touati.
We would like to thank the
members of ANAES’ Scientific
Council, who kindly reread this
document and provided useful
criticism.

Communication Fondation de l’avenir
Fondation de l’Avenir
for medical research
In 1987, the Mutualité Fonction Publique took
the initiative to create the Fondation de
l’Avenir, and brought an initial capital ~3.8
million € (25 million French francs). The
Association Française de Cautionnement
Mutuel also made a donation of ~300.000 € (2
million French francs) to increase this capital.
In 1998 the Fondation de l’Avenir was stateapproved
as a common interest organization
and is now the fifth private organization in
France to support medical research.
“In 1987 we were very few involved in this
foundation. At that time, in France, the
applied research in the surgery field used to
be badly coordinated and fairly neglected in
comparison with the fundamental research,
although it certainly is an essential field in
health care. By creating the Fondation de
l’Avenir, we intended to make it possible for
the transfer of the technological and scientific
progress towards medical field in general,
more particularly towards surgery. This is our
mission.” said Jean Pierre Davant, President
of the Foundation between 1987 and 1999.
Today the Foundation brings together
surgeons and physicians from various fields,
working in the biggest hospitals in France, and
supports research projects all over the
country. The Foundation is now well known
and highly appreciated by researchers, as its
impact on the improvement of surgical
techniques and healthcare practice is
increasing every day. It supports financially
about forty research projects per year in these
fields. Since 1987, 500 research projects have
received financial support from the
foundation, representing a total amount of
11.5 Meuros.
48 ARGOS SpineNews N° 6- September 2002
The 2nd Meeting Of the
Fondation de l’Avenir was held
April, 9th 2002 at the Institut
Mutualiste Montsouris, in Paris.
Four main topics were developed
during the round tables :
1. Spine surgery : when and why,
what risks and what future ?
2. Retina and cornea : encouraging
research.
3. Presbyacusia : what solutions could
be proposed to 4 million French
people ?
4. The liver graft and its alternatives
The spinal pathologies have several
components - cellular, genetic,
biomechanical environmental,
psychological etc - thereby the
orthopaedic and surgical treatments
should take into account all these
factors that influence not only the
pathologic evolution but also the
clinical and functional outcome after
treatment. In this context, the
Fondation de l’Avenir found it natural
to support multi- disciplinary
research projects, encouraging the
teams involved to consider the spine
as a global entity.
We will present hereafter the round
table discussion on the spine surgery
and on the risks that may occur in this
field. Most of these projects were
substantially supported by the
Fondation de l’Avenir, after evaluation
and approval of the Scientific Board.
The research teams presenting their
work owe to the Foundation part of
their protocol set up as well as the
preliminary results of their studies
allowing for the building-up of the
complex puzzle of spine pathologies
and treatments.
This discussion started by a
presentation of Doctor Christian
Mazel, Head of the Department of
orthopaedic surgery at the Institut
Mutualiste Montsuris, Paris, who
explained that spine surgery, in spite
of its bad reputation, may be a
necessity in certain severe

Professor Yves Pouliquen
pathologies, like tumours,
deformities, traumas and
degenerative diseases.
The spine surgery aims to restore the
physiological functions of the spine,
mainly the posture, balance and
mobility. In severe cases, the spinal
fusion is necessary in order to
stabilize the spine, after having
decompressed the nerve roots and/or
the spinal cord, as well as after having
removed a tumour situated onto one
or several vertebrae, or after having
performed correction maneuvers on a
deformed spine.
The risks to be taken into account
were presented by Professor Jean-
Noël HEULEU, from the Centre de
Médecine Physique et de
Réadaptation, la Châtaigneraie.
The technological and scientific
progress in spine surgery offers today
a large range of medical devices
making it possible to improve the
clinical investigation as well as the
surgery itself. The risk comes often
from the fact that the medical schools
are nowadays emphasizing more the
technical aspect than the human one
in the training of the young surgeons.
The clinical evaluation remains
crucial. The MRI, CT, X-rays and all
other modern investigation
techniques should not diminish the
importance of the clinical exam. The
direct contact with the patient may
sometimes provide the surgeon with
particular information that will make
it possible to avoid surgery. One
should always consider that the
surgery is the ultimate solution, but
not necessary the best one. In cases
when the surgery has to be
performed, the post-operative
rehabilitation is the warrant of a
satisfactory clinical and functional
result and has to be both technical
and psychological. Modern
technology cannot replace humanism,
and this is the main statement a
surgeon or a physician should always
remember.
The medical imaging investigation
procedures were brilliantly presented
by Professor Jean-Claude DOSCH,
Head of the Radiology Department at
the Centre de Traumatologie et
d’Orthopédie de Strasbourg. The
conventional X-ray film is the first and
most utilized technique for all spinal
pathologies. In complement to the
static X-rays, the dynamic X-rays offer
the possibility to study the mobility of
spinal segments in order to detect
abnormal movements and instability.
Nevertheless, this technique cannot
provide the surgeon with all the
information needed on both the bony
and the soft tissues. Therefore, CT
scan is often used for fractures, but an
MRI becomes absolutely necessary in
cases of intervertebral disc diseases.
For arthritic joints, the CT scan makes
it possible to represent the joint in
three dimensions for a qualitative
evaluation.
The technological progress is obvious,
but one cannot forget that most of
these techniques allow investigation
on patients in lying position, while the
main functions of the human spine are
balance and posture control in
standing position. Therefore, future
research studies should target the
development of revolutionary
investigational techniques on
standing patients as well as on
dynamic MRI.
Professor Wafa Skalli, from the
Laboratoire de Biomécanique,
ENSAM, Paris, then presented the
main aspects of personalized 3D
geometrical and mechanical
modelling of the spine using
stereroradiography, a less invasive
technique than the CT scan that
proves to be very accurate. The
models are designed in order to help
the surgeon in his daily practice, by
allowing him to analyze the spine in
three dimensions, before and after
Communication Fondation de l’Avenir
surgery, as well as at any time during
the follow-up. Furthermore, the
mechanical modelling consists in
incorporating into the model both the
physical properties of the bony and
soft tissues and the mechanical
behaviour of a given spine. These
models are already used in order to
test spinal implants and they will soon
make it possible to simulate certain
surgical manoeuvres, to compare
different concepts, to have an image
of the predictive result for a given
patient before entering the operating
theatre. In the future, the surgeon will
have the possibility to make a
complete planning of his surgical
strategy and also to evaluate preoperatively
the results of his surgical
maneuvers.
The cellular aspects of spinal
pathologies were then presented by
Doctor Serge Poiraudeau. His studies
aim at better defining the factors
responsible for the interveretebral
disc degeneration, since 95 % of back
pain is due to degenerative
pathologies. Two main groups of disc
related pathologies can be defined :
degeneration and disc hernia.
Therefore two different approaches
should be considered :
- the mechanical approach that will
study the mechanical constraints in
the disc, that might result in disc
hernia in cases of complex
pathological constraints;
- the cellular approach which takes
into consideration the different
tissues of the intervertebral disc.
Dr Serge Poiraudeau believes that
mechanical constraints in the disc
could influence the production of
matrix proteins, which would have
certain consequences on the
behaviour and on the degenerative
process of the intervertebral disc.
The study of the results of different
stimuli on the intervertebral disc
under mechanical constraints will
probably allow in the future the
development of local chemical,
genetic or cellular therapies, that will
make it possible to avoid surgery in
some specific cases.
Another important research topic in
spinal surgery is synthetic grafts.
They are often necessary in spinal
September 2002 - N° 6 ARGOS SpineNews 49

Communication Fondation de l’avenir
surgery, but Professor Norbert
Passuti, from Nantes, and Hervé
Petite (INSERM) underlined the
potential risks associated with the use
of allografts :
- small quantity, often insufficient;
- complications such as pain, scars,
excessive bleeding, fractures.
With allografts, there is a risk of
transmissible viral diseases. Thus,
recent research projects focus on the
development of a hybrid bone.
The reference in this study is the
autogenous graft, that incorporates a
calcified basis, growth factors, osseocompetent
cells. The studies in
cellular engineering started in 1990.
After having studied animal bone, it
seemed that the human cells could
proliferate in culture. To make these
cells efficient, they have to colonize a
specific environment, a biomaterial,
that has to meet several
requirements :
- to be biocompatible;
- to have appropriate physical and
mechanical features;
- to be permeable for blood vessels;
- to be easy to produce.
Copyright© Fondation de l’Avenir
Professor Yves Pouliquen
50 ARGOS SpineNews N° 6- September 2002
Polymers and matrixes meet these
requirements. The results of the
current study on sheep will probably
allow for the production of a specific
cellular therapy product.
What is the evolution of scoliosis ? Is
scoliosis evolving towards
stabilization or towards worsening ?
These are just some of the questions
Doctor Eric Viguier, surgeon at
ENVA (École Nationale Vétérinaire
d’Alfort), would like to answer after
having developed an experimental
scoliotic model in the sheep.
The aim of this study is to create an
animal model as similar as possible to
the human model. This is why big
animals cannot be used, as the
vertebrae dimensions are
fundamental in this context. This
study is already well advanced, but
the scoliosis pattern that has been
observed in the animal model is not
yet completely reproducible.
Nevertheless, the observed deviations
are constant. In the near future, the
results of this experimental study will
probably allow the researcher to
extrapolate their
conclusions to
human scoliotic
model. The aim of
this animal model
is to make it
possible to test
different spinal
implants designed
for scoliosis
correction.
The role of
informatics in
spine surgery was
then presented by
Doctor Alexandre
Templier, General
Manager of
Surgiview, Paris,
who underlined
the limits in today
use of informatics
as well as main
developments
that could be
useful in routine
clinics.
The concept, a
priori relatively
large, of
computer-aided surgery, is often
assimilated to the surgical navigation
(surgical gesture guided by image) or
to robotics (semi-automated
realisation of a surgical gesture). The
major interest of these technologies
lies essentially in the precision and
exactitude they bring to the
realization of the surgical gesture. In
the particular case of the spine
surgery, the navigation only applies to
the pedicular trajectory which
requires a very precise gesture
because of the major neurological
risks associated to this surgical act.
But apart from the accuracy of the
gesture, the spinal surgeon is
confronted with a major uncertainty
regarding the restoration of the spinal
and global balance of the patient,
following the surgery. Indeed, today
there is no consensus relative to the
way the ideal profile of a spinal
osteosynthesis is determined for a
given patient. Yet in most cases, the
objective of the spinal surgery is to
restore a physiological posture and
balance. The lack of consensus on the
way to precisely adjust the curves of a
spinal osteosynthesis for each patient
can be explained by the lack of tools
enabling to accurately analyze the
geometry of bones, articulations,
muscles and ligaments, the articular
kinematics and the global posture of
patients. The development of this new
generation of tools is the objective of
several research projects developed
in collaboration with the Laboratoire
de Biomechanique, ENSAM, Paris
and the Laboratoire de Recherche en
Orthopédie et Imagerie Médicale,
ETS, Montréal.
The round table rich presentations on
several aspects of spine surgery were
followed by a very animated
discussions between the round table
participants and the floor. The
afternoon sessions were entirely
dedicated to the other three round
tables that brought together high
scientific level researchers from all
over the country. The following
presentations and discussions proved
once again the impact of the
Fondation de l’Avenir on the
development of medical research in
France. ■
– Anca Mitulescu