8th International Argos Symposium p12 - ArgoSpine

N°9 - April 2004 

SpineNews 

News from the world of Spinal surgery and Biomechanics 

www.argos-europe.com 

6The 8th International 

Argos Symposium 

Adjacent level degeneration after fusion 

20A classification 

of biomaterials 

Yves Debacker 

Consultant in Biomaterials 

substitutes in 2004 

Claude Schwarz 

23Bone 

Founding president 

of Pro Biomateria Group (GECO) 

as a bone supply 

Pr Evelyne Lopez 

32Nacre 

Muséum d’histoire naturelle 

Paris FRANCE 

N. Francaviglia 

37Biospacer 

Sant’Elia Hospital 

Caltanissetta ITALY 

with Charles D. 

Ray, MD, MS, FACS, FRSH 

39Interview 

Snowmass Village, Colorado USA 

Focus on : 

Biomaterials 

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

N°9 - April 2004 

SpineNews 

News from the world of Spinal surgery and biomechanics 

Summary 

Communication 

8th International Argos Symposium 6 

Best poster presentation award 12 

Interview with Charles D. Ray 39 

Evaluation 

Nacre as a bone supply 32 

Biospacer : an innovative intervertebral alumina spacer 37 

Training 

A classification of Biomaterials 20 

Bone substitutes in 2004 23 

Clinical case discussion 46 

Argos SpineNews - N°9 April 2004 3

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4 Argos SpineNews - N°9 April 2004

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Editorial 

Alexandre TEMPLIER, PhD > 

ARGOS General Manager 

Editorial Director 

The ever-expanding use of biomaterials is 

revolutionizing spinal surgery. Indeed, these 

adjuncts have now become essential parts 

of daily practice. 

Currently, biomaterials are used to replace defective or damaged bone, augment or 

enhance spinal fusion, and limit or prevent perineural fibrosis. Clearly, however, the 

ever-expanding biomaterial options available to the spinal surgeon highlight how far 

these products have developed, and how much potential development remains. 

The term “Biomaterials” can be used broadly to encompass all 

materials that can be safely implanted into the human body. 

Traditionally, the definition has been somewhat more narrow, 

excluding metallic compounds, even those that are biologically 

active. Furthermore, biomaterials can be sub-classified into 

resorbable and non-resorbable varieties. The non-resorbable 

biomaterials – ceramics, bioglass, polymers, and poly-carbons – will 

not be discussed in this issue. Our primary focus will be on 

resorbable materials, whether active or inert. 

Because this topic has captured the imagination of all spinal 

surgeons, we will dedicate this issue to investigating certain 

fundamental questions. What are these compounds ? How do they 

work in the body ? Where can they best be applied to spinal surgery ? 

Specifically, we have asked some of the world’s leading experts to 

share with us their ideas and opinions on biomaterial options for bone 

substitution, fusion augmentation, and vertebroplasty reconstruction. 

We hope that you will enjoy your reading. ● 

< Christian MAZEL, MD 

ARGOS President 


8th Argos Symposium 

Communication 

The 8th International Argos Symposium was held 

on January 29 and 30, 2004, at Maison des Arts & 

Métiers Paris FRANCE. 

More than 300 participants from all over the world gathered 

to discuss on the adjacent levels degeneration after lumbar 

fusion. 

“Degeneration of adjacent levels after fusion” was the topic 

chosen for the 8TH Argos International Symposium, held in Paris, 

on January 29 & 30, 2004. The invited speakers contributed to 

an interesting debate on this very controversial topic. Pr Jean- 

Louis Husson, MD from the University of Rennes, France, Jean- 

Marc Fuentes, MD from Montpellier, France, described the 

natural history of spinal degenerative diseases. Pr Jean-Claude 

Dosch, MD from the University of Strasbourg, France, reviewed 

the medical imaging of degenerative spine. The second part of 

the Symposium was dedicated to the causes of disc 

degeneration at the levels above and below fused segments. 

The next day Pr Wafa Skalli, PhD from the Laboratoire de 

Biomécanique de l’École Nationale Supérieure des Arts et 

Métiers, presented an overview of the biomechanical behaviour 

of the levels adjacent to the fused segment. Then, Pierre 

Roussouly, MD from the Centre des Massues in Lyon, France, 

and Gilles Dubois, MD from Toulouse, France, discussed the 

different methods currently in use to prevent or treat 

degeneration, i.e. detailed sagittal balance analysis and new 

surgical techniques allowing a better protection of adjacent 

levels. The well-known phenomenon of adjacent level 

degeneration after spinal fusion is well-described but poorly 

understood. It is common, but not routine ; it is progressive, but 

maybe slow or rapid in developing. It is a cause for consternation 

and debate, but its causes are myriad and controversial. 

The last session was devoted to open oral communications. In a 

change from previous years, there were special sections of the 

oral communications devoted to papers from Argos-North 

America and Argos-Belgium. A special presentation was made of 

the research that won the 2004 Argos Thesis Award. The best 

poster communication was selected by electronic vote of the 

meetings’ participants and, as is traditional every year, there was 

constant, rapid interaction – both verbal and electronic – 

between the audience and the speakers. 

8 TH International 

Argos Symposium 

“Adjacent levels degeneration after lumbar 

fusion. How to prevent it ? What to do ?” 

Session 1 

The first two discussants for the first session were Pr Jean- 

Louis Husson, MD, Rennes, France and Jean-Marc Fuentes, 

MD, Montpellier, France. Pr Husson opened the session with 

a presentation on the natural history of degeneration in the unoperated 

spine. During his talk, he insisted on the fact that 

“instability” is often an improper term used for what should be 

called “destabilization”. In his opinion, destablization has two 

phases, i.e. elastic and plastic, that occur when spinal flexion 

constraints are lost. Therefore, muscle degeneration plays a 

major role in disc degeneration. Pr Husson then described the 

4 stages of the lumbar disc degeneration 

(DIVA–Dysfonctionnement Intervertebral Acquis/Acquired 

Intervertebral Dysfunction) : Elastic deformation, Occasional 

Dysfunction, Dynamic Stenosis, Degenerative Pseudo- 

Spondylolisthesis or rotatory dislocation. Throughout this 

continuum, there is progressive histological devolution into 

irreversible degeneration of the disc. 

Following Pr Husson’s lecture, Dr Jean-Marc Fuentes 

presented a contrasting point of view on degeneration of unoperated 

spine. In his opinion, there are innate factors and 

acquired factors that lead to disc degeneration sooner or later. 

Dehydration of the discal matrix after the age of 40 is a 

common process that will yield a decrease in discal height and 

disc bulging. In 20 to 30% of the population, annulus fissures 

occur after the age of 30, which will lead to increased pressure 

in the disc and later to ostheophyte formation and, eventually, 

to disc calcification. Posterior arch atrophy is a reaction to this 

process. In conclusion, he indicated that an olisthesis higher 

than 3 mm combined with a 15° angulation will probably result 

into lumbar destabilization. He stressed, furthermore, that the 

posterior joints play a major role in the degeneration process. 


Communication 


The roundtable discussion of the first session involved Jean- 

Louis Husson, Jean-Marc Fuentes, Pierre Roussouly and 

Gilles Dubois who collectively debated the differences 

between the two approaches to spinal destabilization. Jean- 

Louis Husson argued that destabilization occurs when 

anatomical “brakes” are overloaded while Jean-Marc Fuentes 

countered that the spinal degeneration is an age-related 

patient specific process. In other words, while Jean-Louis 

Husson would consider degeneration mostly a chemical 

process, Jean-Marc Fuentes emphasizes the mechanical 

component of destabilization. Pierre Roussouly, MD, Lyon, 

France, added that the sagittal balance and posture as well as 

muscles will greatly impact the development of degenerative 

phenomena. 

An interesting question was discussed in detail : Why do some 

patients complain of pain while others, with the same clinical 

signs of degeneration, do not ? In each case, P Roussouly 

analyses all possible factors and stresses that one must 

differentiate between dynamic pain resulting from facetal 

dysfunction and postural pain arising from muscular 

alteration. In reply, Jean-Louis Husson said that he always 

tries to identify the definitive pain generator. He added that 

the retraction of ischiocavernous muscles should be prevented 

in order to unload the lumbo-sacral transition segment. Jean- 

Marc Fuentes believes that pain does not always come from 

radicular compression but from sometimes venous stasis. He 

also indicated that, in his opinion, obesity will maintain spinal 

pathology but plays no major role in the development of the 

degenerative disease. 

The second part of the first session was dedicated to imaging 

of the degenerative spine, presented by Pr Jean-Claude 

Dosch, MD, Illkirch, France. In contrast to spine surgeons, 

the radiologist’s description of degeneration does not take into 

account the chronology of the destabilization process. In this 

context, the role of the radiologist is to use the appropriate 

medical imaging methods in order to detect all of 

degeneration’s signs. Thus, MRI is mostly utilized to detect 

discal degeneration while static Xrays will show a loss of disc 

height. As for destabilization, dynamic Xrays, i.e. 

flexion/extension lateral radiographs, are the most appropriate 

studies, even though MacNab traction osteophytes, which are 

destabilization indicators, may be detected on static Xrays as 

well. As for the facet joint dysfunction and stenosis, both CT 

scan and Xrays will allow for detection. 

In conclusion, Pr Dosch indicated that degenerative lesions 

are quite frequent, even in asymptomatic volunteers with as 

many as of them showing degenerative signs. Later on, 

pathologic degeneration may occur depending on the 

individual situation at a given moment. Pr Christian Mazel, 

MD, Paris, France and Jean-Marc Fuentes, MD closed the first 

session with two lectures on adjacent level degeneration after 

fusion. Pr Mazel reminded the audience that up to 50-70% of 

operated patients will develop adjacent level degeneration 5 to 

10 years after surgery. Furthermore there is no consistant 

pattern of adjacent level degeneration, nor is its pattern and 

development dependant on the initial diagnosis – HNP, 

stenosis, spondylolisthesis, or discopathy. Pr Mazel stressed 

the importance of a thorough pre-operative evaluation of 

destabilization and instability. Second, but no less important, 

he believes that the patient’s position on the operating table 

plays a major role in the sagittal correction. Instrumentation 

features are also very important, in situ contouring may help 

to restore the sagittal balance, but remains highly operatordependent. 

In conclusion, adjacent level degeneration after 

fusion is multifactorial. Therefore careful pre-operative 

evaluation and surgical planning are mandatory. 

Jean-Marc Fuentes then explained that degeneration after 

fusion is still a controversial issue, emphasizing that some 

believe that all degeneration after fusion is directly due to the 

fusion while others would argue that post-fusion degeneration 

follows the same pattern as the natural degenerative process. 

With this much controversy about the causes of this 

degenerative process, one would not expect consensus about 

the methods available to prevent it. Several instrumentation 

modifications have been proposed - semi-rigid 

instrumentation (Twinflex) as developed by Mazel, 

ligamentoplasty as proposed by Graff, dynamic neutralization 

as recommended by Dubois or, today’s hottest topic, discal 

arthroplasty. Jean-Marc Fuentes concluded by reminding the 

audience that the aging process is inevitable for us all. 

A heated discussion followed these two lectures. Gilles Dubois 

remarked that Modic I stage, when asoociated with pain, used 

to be and still is a good indication for fusion but it is now 

proven that this stage may be reversible after orthopaedic 

treatment and dynamic stabilization. In reply, Pr Dosch 

argued that Modic I was often associated with subtle subclinical 

instability. Pr Jean-Paul Steib, Strasbourg, France, 

emphasized the role of discography to detect painful discs, 

while P Roussouly reminded again the importance of sagittal 

balance and of the construct length to prevent adjacent level 

degeneration. In addition, Franck Ganem, MD, Caen, France 

said that he often sees patients that will not develop pain in 

spite of a degenerated adjacent level because their postural 

balance has been maintained or reconstructed. Pr Wafa Skalli, 

Paris, France added that muscles play a vital, and often 

overlooked, role in the re-balancing process. Good muscular 

tone would probably explain the absence of pain in certain 

patients with evident adjacent level degeneration after fusion. 

Session 2 

The second session began with a description of the 

biomechanical behavior of the adjacent levels after fusion 

presented by Pr Wafa Skalli, Paris, France. Pr Skalli showed 

the importance of Finite Element Modeling for the simulation 

of the biomechanical behavior of vertebral and discal 

structures, either individually and collectively, within the 

spine. This new and evolving techniques allow for the 


8th Argos European Symposiumschool Communication of surgery 

Buzzer vote results 

Thursday 29 st January 2004-pm 

You are : 

simulation of alterations in disc constraints in pathological 

situations as well as after fusion. The latest studies in the field 

show that a slight alteration in the gravity line (10 mm ventral 

from its physiological location) will result in a 10-fold increase 

in the loads seen by the disc. Nevertheless, the body may 

compensate for these alterations with good muscular tone. In 

Pr Skalli’s words, posture plays a paramount role in the 

degeneration process – in either the un-operated or postfusion 

spine. She stressed that 50% of lumbar motion is 

concentrated between L4 and S1. Fusion of these segments 

necessitates stress transfer to adjacent discs and the hip joints. 

Excellent muscular tone and balance are required to 

compensate for such a significant alteration in spinal motion. 

New computerized tools for dynamic analysis, such as 

SpineView ® (SurgiView, Paris, France) are now available to 

quantify postural parameters and the Mean Centers of 

Rotation (MCR) for lumbar and cervical spinal units. Mobility 

is defined both by the amplitude of the flexion extension 

movement and by the way the movement is obtained through 

the MCRs. The location of these centers of rotation will 

indicate whether or not the vertebral units have a 

physiological movement, whatever the amplitude of the 

movement. MCR analysis must be included when 

investigating the degenerative spine, before and after surgery, 

Orthopaedic surgeon 

Neurosurgeon 

Researcher 

Radiologist 

Other profession 

52% 

Both 

You are from : 

Africa 

Asia 

Australia 

Europe 

North America 

South Africa 

49% 

33% 

3% 

3% 

13% 

28% 

English speaker 

21% 

French speaker 

3% 

10% 

0% 

18% 

1% 

In your professional activity, 

how many spine surgeries 

do you perform per year ? 

According to you, adjacent 

level degeneration 

after fusion can 

be avoided thanks to : 

69% 

less than 30 years old 

between 30 & 40 years old 



60 years old & more 

Male 

Female 

13% 

4% 

19% 

34% 

32% 

11% 

87% 

How many times did you 

attend the Argos Symposium ? 

Once 

Twice 

Three times 

Four times or more 

0 to 50 

50 to 100 

100 to 150 

150 & more 

A preoperative analysis of the sagittal balance 

A complementary soft restabilization 

A dynamic fusion 

A combination of all these 

35% 

20% 

10% 

35% 

22% 

29% 

17% 

32% 

40% 

8% 

13% 

40% 

Are you convinced about 

the interest of posterior 

soft stabilization systems ? 

Yes completly 

I would rather say yes 

I would rather say no 

Not at all 

24% 

32% 

24% 

19% 

> Visit of the posters 

Have you ever used a system 

intended to avoid adjacent level 

degeneration overlying a fusion ? 

Yes 

No 

49% 

51% 


Communication 


as they can prove to be excellent predictors of degeneration. 

Muscle modeling by means of Finite Element Models is also 

available. Since muscular compensation is one of the main 

factors that affect restabilization and mobility transfer, 

individual analysis of the muscular capacity may provide a 

prognosis on the success or failure of fusion. 

Gilles Dubois then presented the biomechanical issues related 

to the soft stabilization techniques. Research studies have 

shown that mobility increases at the upper adjacent level and 

will decrease at the lower adjacent level after fusion. To achieve 

the same global displacement, upper levels are required to 

move more. Dr Dubois believes that the controversies 

surrounding the biomechanics of the adjacent level after fusion 

are, yet unresolved but, in his opinion, adjacent levels may be 

preserved by a dynamic neutralization device. 

Next, Pierre Roussouly, Lyon, France, discussed the “ideal” 

physiological balance hypotheses, emphasizing the 

importance of the pelvic incidence in defining the best posture 

for a given individual. In his opinion, the pelvic incidence will 

determine the compensatory capacities of each individual, i.e. 

a lower incidence will result in a lower capacity of 

compensation. He also presented a computerized tool 

designed by his research team for the calculation of the 

posture and balance parameters from plain Xrays. The 

research studies he conducted led him to classifiy the sagittal 

profiles into 4 groups, depending on the pelvic and spinal 

parameters. Each class has different prognostic factors for 

early or late degeneration. He also stated that spinal 

curvatures are not always defined by same vertebrae, e.g. 

theoretical L1-L5 lordosis does not necessarily correspond to 

the real lordosis, which is defined by the vertebrae located at 

the area of curvature change. Depending on the sacral slope, 

the lordosis apex will change. 

The discussion that followed the second session was mostly 

concerned with compensation ability. P. Roussouly explained 

that a balanced posture requires that C7 be always placed 

directly above the center of gravity. However, as added by Pr 

Skalli one cannot “force” postural balance, which depends on 

different morphotypes. Nevertheless, prognostic factors do exist 

and should be taken into consideration in order to help the 

patient develop individual compensation strategies. In response 

to Dr Roussouly, Jean-Marc Fuentes reminded the audience 

that, whatever the spinal pathology, the labyrinth system will 

always bring head in an adequate position. So, he asked, why 

use C7 instead of the center of external acoustic meatus 

(CEAM) ? Pierre Roussouly replied that pelvic parameters 

should be the starting point in posture and balance analysis. 

Pr Christian Mazel raised the issue of pain in the seated 

position. Is there any biomechanical reason for this ? Pr W 

Skalli responded that when seated, the individual is in a 

hypolordotic situation, and that the thereby tensed ligaments 

result in an alteration in proprioception and, thus, the muscles 

will not be appropriately activated. 

Guest speakers round table discussion : 

> From left to right : G. Dubois, MD, Pr JL. Husson, JM Fuentes, MD, P. Roussouly, MD, Pr W. Skalli, PhD 


8th Argos European Symposiumschool Communication of surgery 

Future potential topics in Argos symposiums : 

- arthritic lumbar scoliosis, correction 

and decompression or 

decompression & fixation ? 

Interesting 

Unintersting 8% 

92% 

- degenerative spondylolisthesis : 

decompression and fixation 

or decompression alone ? 

- Cervical disc prostheses, 

indications, complications, 

results 

Buzzer vote results 

Friday 30 st January 2004-pm 

Interesting 

Unintersting 

Interesting 

Unintersting 

16% 

15% 

84% 

85% 

In rebuttal, P Roussouly argued that the seating position is not 

necessarily more risky than standing, particularly standing and 

bending and lifting as laborers do. At the same time, there is 

no general rule for fusion indications. In cases of painful 

instability fusion may be the best alternative, but one must not 

forget that some patients are more likely to recover with 

physiotherapy than others. Therefore fusion should be 

indicated mostly for patients with very stiff spines, when 

reeducation is impossible. 

According to you, adjacent 

level degeneration 

after fusion can 

be avoided thanks to : 

Detailed appreciation of the session : 

Knowledge content 

Profitability in my practice 

Poor 

Fair 

Good 

Excellent 

2% 

6% 

Personnal interest 

Poor 

Fair 

Good 

Excellent 

Welcome conditions 

Excellent 

Good 

1% 

8% 

A preoperative analysis of the sagittal balance 

A complementary soft restabilization 

A dynamic fusion 

A combination of all these 

30% 

29% 

63% 

62% 

45% 

47% 

Poor 

Fair 

Good 

Excellent 

0% 

0% 

Quality of animation 

Poor 

Fair 

Good 

Excellent 

Scientific sessions 

Excellent 

Good 

8% 

33% 

5% 

20% 

2% 

10% 

Average 7% 

Average 11% 

44% 

45% 

67% 

67% 

30% 

59% 

The last part of the session was dedicated to the presentation 

of soft stabilizations of the adjacent level of fusion. These 

techniques, presented by Gilles Dubois, are meant to prevent 

degeneration by dynamic neutralization of abnormal 

movements. In laboratory testing, the Dynesis system was 

able to normalize the movement of the levels adjacent to the 

fused segment. Examples were provided that showed Modic I 

degeneration reversing over time in segments stabilized by 

the Dynesis system. These phenomena could be explained by 

rehydration of the disc. Christian Mazel asked if there was an 

increased risk of developing kyphosis with Dynesys. Gilles 

Dubois answered that there does not appear to be a significant 

risk since Dynesys strives to restore physiological lordosis. Pr 

Jean Louis Husson then asked whether osteolysis around the 

screws had been observed, presumably due to excessive 

stiffening. Dr Dubois replied that the fixation is customized to 

the individual patient and, therefore, no excessive rigidity was 

noticed. 

A pertinent question was raised by the audience : Is there an 

“ideal” posture that all fusions should aspire to recreate or 

should individual morphotypes be taken into account? P 

Roussouly explained that a “bad” spine will always be a “bad” 

spine, meaning that morphotypes must always play an 

important role in decision making. Nevertheless, he advocated 

restoration of lordosis when possible. ● 


Free oral presentation session : 

This year’s symposium ended with a series 

of very interesting and original free oral 

presentations. 

Frank Fumich, MD, and 

Melvin Law, MD, from 

Argos North America 

presented 3 papers on 

evaluation studies of new 

techniques, i.e 

> Frank Fumich, MD 

microplate laminoplasty 

for cervical stenosis, cage and pedicle 

screw stabilization with morselized 

autograft for the lumbar spine and 

biportal transforaminal endoscopy for 

treatment of pyogenic lumbar discitis. 

Later on, Jean Legaye, 

MD, from Argos 

Belgium first explained 

the importance of gravity 

measurements for the 

assessment of sagittal 

> Jean Legaye, MD 

balance during his first 

talk. Passing to a totally different field, Dr 

Legaye then exposed the performances 

and limits of navigation in spine surgery. 

Agnes Raould, MD, from 

Beaujon Hospital, 

France (team of 

Professor Pierre Guigui, 

MD) gave a talk on the 

importance of the 

> Agnès Raould MD 

evolution of mean 

centers of rotation (MCR) of levels 

adjacent to a postero-lateral lumbar 

fusion. Indeed the evolution of the MCRs 

location plays a major role in the 

mechanical behavior of lumbar spine and 

may therefore predict adjacent 

degeneration, concluded Ms Raould.4 

David Mitton, PhD, from 

the Biomechanics 

Laboratory of ENSAM, 

presented an original 

study on the dynamic 

response 

of 

> David Mitton, PhD 

intervertabral discs, 

based on an experimental approach. The 

study allowed the evaluation of the 

intervertebral disc’s viscoelastic 

properties and the results of the study 

showed high correlations between these 

properties and the degeneration grade. A 

direct consequence of this study may be 

the design of more appropriate nonfusion 

systems for lumbar motion 

restoration. 

After this Biomechanics session, Kiyochi 

Kumano, MD, from Japon, discussed the 

changes in lumbar sagittal alignment after 

TLIF, based on a radiological evaluation. 

His study on 36 patients operated 

between December 2000 to June 2003 

with TLIF for degenerative lumbar 

diseases, showed that lombosacral lumbar 

lordoses in single level fusions were stable 

several months postoperatively. He 

thereby concluded that the single level 

fusion with TLIF is more advantageous 

than the multi level one. 

> Antonio Castellvi, MD 

The evaluation of the 

impact of semirigidity on 

the prevention of 

adjacent level 

degenerative disc 

disease is the purpose of 

a prospective study 

presented by Antonio E. Castellvi, MD, 

from Florida, USA. Dr Castellvi intends 

to enroll up to 100 patients in 2 years, 

with either L5-S1 DDD, dynamic 

stenosis, or iatrogenic instability and 

failed previous fusion, in order to have a 

clear estimation of the clinical outcome 

after fusion with semirigid 

instrumentation. 

Michel Bidermann, MD, Switzerland, 

presented his results involving 20 

patients who have underwent 

monosegmental fusion above the L5-S1 

level, in order to determine whether or 

not the floating L4-L5 fusion leads to 

better mobility recovery than 

lumbosacral fusions. His study showed 

that a good outcome of L4-L5 fusions is 

correlated with preoperative clinical and 

radiological signs of instability. 

Therefore, Dr Bidermann concluded that 

the best indication for L4-L5 fusions is 

instability in young patients. 

During the non-fusion techniques 

session, several speakers addressed the 

new stabilization system called Dynesys. 

Othmar Schwarzenbach, MD, form 

Switzerland, presented his first clinical 

results involving 42 patients operated 

with the Dynesys stabilization system in 

addition to PLIF or PLF. Olivier Ricart, 

MD, France, presented the results of a 

prospective study in patients suffering 

from spinal stenosis with degenerative 

spondylolisthesis, while Darrell 

Goertzen, Switzerland discussed the 

effects of flexible devices in motion at the 

adjacent segment after lumbar fusion. 

Another non-fusion restabilization 

instrumentation is the Wallis device. 

Panagiotis Korovessis, 

MD, used this device in 

24 patients in order to 

prevent adjacent levels 

> Panagiotis Korovessis, MD 

degeneration after 

lumbar fusion. His study 

showed that the use of 

such a device in addition to fusion 

maintained the lumbar lordosis and 

reduced disc mobility. No alteration of 

posterior vertebral displacement in 

extension was observed. However, 

olisthesis in flexion increased. G. Matgé, 

MD, Luxemburg, then presented a 

review of interspinous fixation systems, 

dynamic neutralization ones as well as 

the semirigid fixation devices, in order to 

better define the appropriate indications 

for each of these systems. He concluded 

that the non-fusion systems, when used 

instead of rigid systems, may not only 

have a curative indication but also onein 

the prevention of junction syndrome. In 

his opinion, except for severe lytic 

spondylolisthesis, rigid fixation should 

not be indicated anymore for 

degenerative lumbar instability. 

Finally, J.R. Jinkins, MD, 

USA, presented the first 

clinical results of the 

clinical trials on the 

upright, weight bearing, 

dynamic-kynetic MRI 

> Randy Jinkins, MD 

device for spine analysis. 

The potential relative beneficial aspects 

in spinal imaging of the stand-up MRI 

over that of recumbent MRI include the 

revelation of occult disease dependent on 

axial loading, the unmasking of kinetic 

dependent disease, and the ability to scan 

the patient in the position of clinically 

relevant signs and symptoms. ● 

A. MITULESCU, P. KEHR, C. MAZEL 

Argos SpineNews - N° 9 April 2004 11

Bone substitutes in 2004 

Communication 

1 2 

Best poster 

presentation award : 

Inter-individual variations 

of the cervical spine biomechanics 

and postural parameters. 

Methods : 

Eighteen asymptomatic subjects (9 men and 9 

women), mean age : 31 years (23-51), mean 

weight : 68 Kg (52-93) were included in the 

study. A stereoradiography exam (fig. 1, 2) (front 

and lateral Xrays) in a standing position, using a 

specific low irradiation Xray system was used to 

obtain a 3D reconstruction of the subject C0-C7 

cervical spine (fig. 3) [1] . 

– R. Saintonge, A. Assi, V. Pomero 

B. Frechede, S. Laporte, W. Skalli 

Laboratoire de biomécanique 

de l’ENSAM Paris FRANCE 

Context : 

The cervical spine posture and global loads 

induced by head weight are important in the 

cervical spine pathology analysis, but they are not 

yet well documented. Our aim is to analyze the 

inter-individual variations of the cervical spine 

biomechanical and postural parameters using the 

EOS low irradiation Xray system 

and 3D reconstruction. 

3 

The external envelopes of the neck and head 

were also reconstructed (fig. 4). Frontal and 

sagittal curvatures between the intervertebral 

level of C3-C7 were then calculated, as well as 

the posterio-anterior and lateral location of the 

center of external acoustic meatus (CEAM, 

estimating the gravity center of the head [2] ) with 

12 Argos SpineNews - N° 9 April 2004

Communication Bone substitutes in 2004 

regard to the intervertebral center of C7-T1. A 

mass distribution model of the head and of neck 

slices allowed to estimate global loads at each 

intervertebral level (fig. 5). The head mass was 

evaluated using a regression equation based on 

the subject weight and head perimeter (fig. 6) [3] . 

The mass of each neck intervertebral slice were 

obtained using density, volume and center of 

gravity of vertebrae and soft tissues (fig. 7) [4] . 

4 

5 

Results : 

The observed cervical spine curvatures were 

straight (5 subjects) or lordotic (11 subjects) 

(fig. 8). For the lordotic curve, the mean sagittal 

curve was 20° (6.5-43°) and the mean frontal 

curve was 11° (4.6-21°). The mean CEAM 

location was 33 mm (4-77 mm) 

anterior to C7-T1 center. CEAM 

was often laterally deviated, left or 

right, 5 to 13mm, either left (2 

subjects) or right (6 subjects). The 

main global loads were 

compression forces and flexion 

moments (see table). A slight 

lateral bending moment also was 

observed, reaching 0.4 Nm. 

Discussion and Conclusion : 

Head location varied in a wide range 

inducing inter-individual variations 

in flexion moments. The global loads 

obtained were compatible with 

published load tolerances [5] . This 

study underlines relationship 

between global intervertebral loads 

and spine configuration. Future 

muscle regulation model should 

allow to better understand normal or 

pathologic cervical spine behavior. 

References : 

[1] V. Pomero, D. Mitton et al, Clin 

Biomech, 2004, in press. 

[2] JM. Vital and J. Senegas, SRA, 

vol. 8, pp. 169-73, 1986. 

[3] C. Clausser, J. Mc Conville, 

and J. Young, AMRL-TR-69- 

70, 1969. 

[4] J. Mc Conville, C. Clausser, 

and J. Cuzzi, AFAMRL-TR-80- 

119, 1980. 

[5] R. W. Nightingale, BA. 

Winkelstein et al, J Biomech, 

vol. 35, pp. 725-32, 2002. 

Acknowledgements : 

1. 3D reconstruction methods 

were developed in collaboration 

with LIO Montréal. 

Loads due to gravity : mean (extreme) values 

Global intervertebral loads for the cervical spine in standing position (mean and extreme values) 

C0-C1 C1-C2 C2-C3 C3-C4 C4-C5 C5-C6 C6-C7 C7-T1 

Compression forces (N) 41 (37-49) 44 (41-52) 46 (42-53) 48 (43-56) 49 (44-58) 51 (45-60) 54 (47-64) 57 (50-69) 

Flexion moments (Nm) 0,6 (0-2) 0,6 (0-2,1) 0,7 (0-2,2) 0,7 (0-2,3) 0,8 (0-2,5) 0,9 (0-2,7) 1 (0-3) 1,3 (0,2-3,3) 

2. EOS system was developed in 

collaboration between LBM- 

ENSAM, SVP Hospital, LIO, 

Pr Charpak and Biospace 

company. 

6 7 

8a 

8b 

Fig 1 : Stereoradiography in the EOS ® system 

Fig 2 : Frontal and lateral X rays in standing position 

Fig 3 : 3D reconstruction of C0-C7 [1] 

Fig 4 : 3D reconstruction of head and neck envelope 

Fig 5 : Calculation of loads due to gravity forces 

Fig 6 : Calculation of the head mass 

Fig 7 : Calculation of the mass and COG of 

intervertebral slices 

Fig 8 : Types of curvature 

8a : Straight for 5 subjects 

8b : Lordotic for 11 subjects 

Mean sagittal curve : 20° (6.5-43) 

Mean frontal curve : 11° (4.6-21) 


Third Annual 

ARGOS NORTH AMERICA 

CONFERENCE 

West Coast Attitude, East Coast Latitude 

Lumbar Degenerative Diseases : 

When and How to Fuse ? 

Indications, Graft Alternatives and Instrumentation. 

6-7 AUGUST 2004 

Sessions to include : 

- Scoliosis 

- Lumbar Fusion 

- Biologic graft alternatives 

Educational objectives : 

Following this course, participants should : 

- Understand the relevant benefits and limitations of biologic alternatives 

to autologous grafting 

- Compare and contrast the various surgical approaches to the treatment 

of lumbar degenerative conditions and relative merits and limitations 

- Have a working understanding of several different instrumentation 

alternatives for fusion of the degenerative lumbar spine. 

- Begin to understand the relative role of fusion vs. discal arthroplasty in 

the treatment of the degenerative lumbar spine. 

This activity has been planned and implemented in accordance with the Essential Areas and Policies of the Accreditation 

Council for Continuing Medical Education (ACCME) through the joint sponsorship of the WVU School of Medicine and 

ARGOS North America. The WVU School of Medicine is accredited by the Accreditation Council for Continuing Medical 

Education to provide continuing medical education for physicians. The WVU Office of CME designates this educational 

activity for a maximum of 11.5 category 1 credits toward the AMA Physician’s Recognition Award. Each physician should claim only 

those credits that he/she actually spent in the activity. 

Educational Grant provided 

by REO SpineLine, LLC

GUEST SPEAKERS 

TO INCLUDE: 

Julie Bearcroft, PhD 

Edward Benzel, MD 

John E. Hall, MD 

John F. Kay, PhD 

Henry J. Mankin, MD 

Jack Parr, PhD 

Jean-Paul Steib, MD 

Michael Y. Wang, MD 

C ALL FOR ABSTRACTS 

Electronic submission deadline : 

June 1, 2004 11:59 pm cst 

Submit to : argosNA@argosna.org 

Submission rules : 

• Abstracts must be submitted by June 1, 2004. All abstracts 

received after that date will not be considered. 

• Abstract must be submitted electronically. 

• Abstract must be submitted in English 

• Abstract must contain the following : 

- No more than 200 words 

- Title 

- List all authors associated with the abstract 

- Presenting author 

- Presenting Author contact information - phone, fax, 

eMail address, mailing address. 

- Institutional affiliations 

• Abstracts are reviewed by ARGOS-NA board members and 

will be read in “blind” fashion. 

• ARGOS-NA will send notification of acceptance via eMail 

to the presenting author on or after June 15, 2004. 

Policies : 

- ARGOS-NA reserves the 

right to withdraw an abstract 

at any time. 

- Presenters of the accepted 

abstracts must register for 

the meeting and pay their 

own expenses. 

- All presenters must adhere 

to the AMA code of Medical 

Ethics, Opinion 8.061 “Gifts 

to Physicians form Industry” 

- All presenters are required 

to provide Conflict of 

Interest Disclosure information 

and FDA disclosure. 

- Authors will be listed in 

Final Program. ARGOS-NA 

will not assume responsibility 

of information provided 

inaccurately. Once an abstract 

is accepted, additional 

authors cannot be added 

- Prior to submission of your 

abstract please ensure that 

you are available to present 

at the meeting. If it is 

impossible for you to present 

your abstract at the 

assigned time, you must 

choose a substitute presenter 

or request to be withdrawn. 

Once Final program 

is printed we will be unable 

to make changes. 

- To withdraw an abstract, 

the presenter must notify 

ARGOS-NA via eMail.

– Pr Kiyoshi Kumano 

FOUNDER & PRESIDENT OF 

THE JPSSSTSS 

– Shigeru Hirabayashi 

CHAIRMAN OF THE 11TH 

MEETING OF THE JPSSSTSS 

11 th Annual meeting of the 

JPSSSTSS * 

18-19 SEPTEMBER 2004 

*Japan Society for the Study of Surgical Techniques for Spine and Spinal Nerves 

Omiya Sonic City Hall 

Omiya Saitama 

www.sonic-city.or.jp 

Sonic-City BLDG 5F, 1-7-5 

Sakuragi-cho, Omiya-ku, 

Saitama-shi, Saitama 

330-8669 JAPAN 

The 11th Annual Meeting of the Japan 

Society for the Study of Surgical 

Techniques for the Spine and Spinal 

Nerves (JPSTSS) will be held at Omiya 

Sonic City Hall, Omiya, Saitama, on the 

18th and 19th September, 2004. As 

President of the meeting, I would like to 

give a few words of greeting. 

Last year, the memorable 10th annual meeting 

was held under Dr. Hiroshi Takahashi as 

President. Starting this year, the society enters 

into its second decade. There are three 

fundamental ideas of the JPSTSS society. First, to 

actively welcome foreign doctors and exchange 

each idea. Second, to encourage cooperation 

among doctors of different departments involved 

in treating the spine and spinal cord to discuss 

many unresolved problems. Third, to encourage 

individual participation in the meeting, that is, 

without restriction due to policies at the place of 

employment. These ideas have been maintained 

since foundation of the society in 1994. The 

numbers of participants who agree with the ideas 

have been increased year by year. The journal of 

the society has been published since 1999. 

Currently, the JPSTSS society has grown to 

become one of the representatives of Japanese 

medical society for study of spine and spinal cord. 

Recently, the concept of EBM (Evidence-Based 

Medicine) has become widely established even in 

Japan and the evidence presented seem to become 

absolute guidelines in medicine. The main 

purpose of this concept is to objectively 

reconsider medical outcomes that have previously 

been subjectively determined by doctors 

themselves. Certainly, this concept has one proper 

direction. However, the evidence is the integrated 

result obtained statistically by comparing cases. 

Therefore, there is possibility that problems 

existing in each individual has disappeared or is 

masked. The evidence may be changed or affected 

by the selection of objects and methods adopted. 

We must recognize that the evidence is evidence 

obtained under restricted conditions, and 

therefore, is not an absolute guideline. Everyday 

we surgeons face patients who have these 

problems and must cure and care each patient in 

a manner suitable for the individual conditions. 

The purpose of the JPSTSS society is to manage 

these individual complexities by making efforts to 

devise surgical techniques. This is one alternative 

direction that differs from that of EBM. 

I have selected two main themes for the 11th 

meeting. One is the surgical management for 

disorders at the junction of the spinal column, a) 

the craniocervical junction, b) the cervicothoracic 

junction. The other is new or recently devised 

surgical techniques for lumbar spinal canal 

stenosis. The junction of the spinal column is 

very peculiar from both anatomical and 

biomechanical perspectives. The disorders at the 

levels are sometimes difficult to manage, 

especially at the craniocervical and cervicothoracic 

junctions, and the treatment must be more 

intensively discussed. Although lumbar spinal 

canal stenosis (LSCS) is a common disease, the 

pathomechanism has not yet been fully 

elucidated. Despite the fact that LSCS is a 

complex syndrome, the treatment has previously 

been discussed as if it is one disease. Treatment of 

this syndrome must be developed in accordance 

with each pathomechanism. 

Omiya is the center of Saitama Shin-Toshin (new 

metropolitan) and convenient to access from 

anywhere in Japan including Narita Airport. 

Omiya Sonic City Hall, the venue for the 11th 

meeting, is very near Omiya Station and adjacent 

to Omiya Palace Hotel. I hope that many doctors 

will take part in the meeting and discuss many 

issues actively. I expect the meeting will be a 

suitable opening for our second decade. 

– Shigeru Hirabayashi 

Department of Orthopaedic Surgery 

Saitama Medical Center, Saitama Medical 

School

Argos’ members list 

Algeria 

Dr BENCHENOUF Mohamed Kamel 

Argentina 

Pr AYERZA Ivan R 

Dr BERNASCONI Juan Pablo 

Dr COLL Pedro Ariel 

Dr D’INNOCENZO Alysudro Cesar 

Dr FERNANDEZ BOAN Osvaldo 

Dr GELOSI Frederic J 

Dr GRECCO Marcelo HG 

Dr LANARI ZUBIAUR Felipe 

Dr LEGARRETA Aroldo Carlos 

Dr MARIANO Noël 

Dr MONAYER Jose Luis 

Dr MOUNIER Carlos Maria 

Dr NEMIROVSKY Carlos E 

Dr PATALANO Luis A 

Dr PLATER Pablo 

Dr RAMANZIN Victor Gust 

Dr RAMIREZ Gustavo 

Dr RODRIGUEZ Roberto Carlos 

Dr ROSITTO Gabriel 

Dr ROSITTO Victor 

Dr RÜDT Tomas 

Dr SELSER Jorge Guillermo 

Dr SEMBER Eduardo 

Dr SIRNA Pablo Mario 

Dr SOLA Carlos A 

Dr SOSA Eduardo Angel 

Dr ZISUELA Roberto Gustavo 

Belgium 

Dr COSTA Henri* 

Dr DELEFORTRIE Guido 

Dr DESMETTE Damien* 

Dr EL BANNA Sabri* 

Dr FORTHOMME Jean-Paul* 

Dr MATHEI Frédéric* 

Dr LEGAYE Jean 

Dr RYSSELINCK Yves 

Brazil 

Dr HÜBNER André Rafaël* 

Canada 

Pr DE GUISE Jacques* 

China 

Dr LEONG John* 

Egypt 

Dr EL-HADIDI Talaat 

Dr SALAH Hossam 

France 

Dr ANTONIETTI Pierre* 

Dr ABIKHALIL Joseph 

Dr ARTIERES Xavier 

Dr BALABAUD Laurent* 

Dr BERNARD Pierre 

Dr BOGORIN Ioan 

Dr BOUVET Robert 

Dr BRAUN Emmanuel 

Dr CORDONNIER Denis* 

Dr CHOPIN Daniel (Honorary member) 

Dr CIAUDO Oreste 

Pr DEBURGE Alain (Honorary member) 

Dr DEHOUX Emile 

Dr DESROUSSEAUX Jean-François* 

Dr DOSCH Jean-Claude* 

Pr DUBOUSSET Jean* 

Dr/Ing DUMAS Raphaël* 

Dr DUPUIS Raphaël 

Dr EDOUARD Brice 

Dr FINIELS Pierre-Jacques* 

Dr GAGNA Gilles 

Dr GANEM Franck* 

Dr GOSSET Franck* 

Dr GRAFTIAUX Alain* 

Pr GUIGUI Pierre 

Dr GUILLAUMAT Michel (Honorary member) 

Dr HEISSLER Pierre* 

Dr HOVORKA Etienne 

Dr JABY Yves 

Dr JUDET Henri* 

Pr KEHR Pierre* 

Pr LAVASTE François* 

Dr LEMAIRE Jean-Philippe 

Dr LEONARD Philippe 

Pr LOUIS René (Honorary member) 

Dr MARMORAT Jean-Luc* 

Pr MAZEL Christian* 

Dr/Ing MITULESCU Anca Andreia* 

Dr MORENO Pierre 

Pr NAZARIAN Serge 

Pr ONIMUS Michel (Honorary member) 

Pr POINTILLART Vincent (Honorary member) 

Dr RAKOVER Jean-Patrick 

Dr RAMARE Stéphane 

Dr RICART Olivier* 

Pr SAILLANT Gérard (Honorary member) 

Dr SAMAHA Dominique 

Pr SENEGAS Jacques (Honorary member) 

Pr SKALLI Wafa* 

Dr SORBIER Joël* 

Dr STEIB Jean-Paul* 

Dr TALEGHANI David Hamid 

Dr/ing TEMPLIER Alexandre* 

Dr TERRACHER Richard* 

Dr VITAL Jean-Marc* 

Germany 

Dr DANNENBERG Jens 

Pr HARMS Jüergen 

Dr KRAPPEL Ferdinand 

Pr WEIDNER Andreas 

Greece 

Dr KALIVAS Lambros 

Dr KORRES Demetre (honorary member)* 

Dr KOROVESIS Panagiotis 

Dr PATSIAOURAS Thomas 

Pr SAPKAS George 

Dr TSAFANTAKIS Manolis 

Dr ZACHARIOU Konstantinos Zacharias 

Hungary 

Dr CSERNATONY Zoltan 

Pr ILLES Tamas* 

India 

Dr MENON K Venugopal* 

Israël 

Dr BRUSKIN Alexander 

Dr CASPI Israel 

Dr LEVINKOPF Moshe 

Dr NERUBAY Jacob* 

Pr SHOHAM Moshe* 

Italy 

Dr ACAMPORA Sergio 

Dr ASCANI Elio PhD 

Dr BADO Flavio 

Dr BASSANI Roberto 

Dr BONACINA Paolo 

Dr BONFIGLIO Giuseppe 

Dr BUSCH Rolf 

Dr/Ing D’AMICO Moreno* 

Pr DENARO Vincenzo 

Dr FRANCAVIGLIA Natale 

Dr GAMBADORO Cesare Maria 

Dr LAAGER Charles-Marc* 

Dr RODIO Dario 

Pr ROSA Michele Attilio 

Dr RUSSO Tullio Claudio 

Pr SALPIETRO Francesco 

Dr TAMORRI Marco 

Dr UGGERI Massimo 

Pr VENTURA Fausto 

Japan 

Dr DEZAWA Akira 

Dr KUMANO Kiyoshi* 

Dr KUNOGI Jun-Ichi* 

Dr TSUNODA Nobuaki 

Korea 

Pr CHO Jae-Lim 

Pr KIM Young-Soo (Honorary member) 

Pr KIM Yung-tae 

Dr LEE Sang Ho 

Pr OH Seong-Hoon 

Luxembourg 

Dr WIJNE Adrien* 

Marocco 

Dr BENZAKOUR Thami 

The Netherlands 

Dr LUITJES Willem F 

New Zealand 

Dr DUTOIT Francois 

Nigeria 

Dr ADEBULE Gbolahan 

Poland 

Dr ZARZYCKI Daniel 

Portugal 

Dr CANNAS Joao 

Dr DE ALMEIDA Luis 

Romania 

Pr JIANU Mihai* 

Senegal 

Dr SEYE Seydina Issa Laye SENEGAL 

Slovenia 

Dr CORBACHO GIRONES Jose Maria 

Dr FOKTER Samo K* 

South Africa 

Dr WASSERMAN Johan 

Spain 

Dr ALVAREZ RUIZ Fernando 

Dr BOTELLA Carlos 

Dr BRAGADO NAVARRO Diego 

Dr CABRERA MEDINA Sergio 

Dr CAMPUZANO Alfonso 

Dr CASAMITJANA FERRANDIZ JM* 

Dr CHAROSKY Sebastian 

Dr CIMARA DIAZ J Ignacio 

Dr CORBACHO GIRONES Jose Maria 

Dr DE BLAS ORLANDO Alvaro 

Dr DE MIGUEL VIELBA Jose Antonio 

Dr DIAZ-MAURINO Juan 

Dr ECHEVERRI BARREIRO Angel Jorge* 

Dr FERNANDEZ BOAN Osvaldo 

Dr FERNANDEZ GONZALEZ Manuel 

Dr FERNANDEZ MANCILLA Fernando 

Dr FONT VILA Frederic 

Dr GARCIA RODRIGUEZ Luis Antonio 

Dr GIMENEZ Antonio 

Dr GONZALEZ Francisco 

Dr GONZALEZ RODRIGUEZ Ernesto 

Dr GONZALEZ SAMANIEGO Angel 

Dr HERNANDEZ GARCIA Cesar 

Dr HERNANDO ARRIBAS Carlos 

Dr HEVIA Eduardo 

Dr HUERTA Juan 

Dr ISLA GUERRERO Alberto 

Dr MARTIN BENLLOCH Antonio* 

Dr LAGUIA Manuel 

Dr LLOMBART AIS Rafael 

Dr LOPEZ-OLIVA MUNOZ Felipe 

Dr LOZANO-REQUENA Juan Antonio 

Dr LUNA Carlos 

Dr MARUENDA Jose Ignacio 

Dr MATA Pedro Ramon 

Dr MATA Jr Pedro Ramon 

Dr PEREZ JIMENEZ Cesar 

Dr RODA FRADE Enrique 

Dr SANCHEZ VERA Manuel 

Dr SANFELIU GINER Miguel 

Dr SANTOS BENITEZ Hugo 

Dr SOPESEN MARIN José Luis 

Dr VELLOSO LANUZA Agustin 

Dr VICENTE THOMAS Javier 

Dr VILAR PEREZ Julio Alfonso 

Switzerland 

Dr BEDAT Philippe* 

Dr BIEDERMANN Michel 

Dr DUTOIT Michel* 

Pr JEANNERET Bernhard 

Dr KAECH Denis* 

Dr LUTZ Thomas Walter 

Dr SCHIZAS Constantin* 

Dr SELZ Thierry* 

Syria 

Dr ALOMAR Taha 

Tunisia 

Dr KAMOUN Mohamed Habib 

Dr KHOUADJA Fathi 

Dr LADEB M Fethi 

Dr M’BAREK Mondher 

Dr MILADI Mongi* 

Dr TRABELSI Mohsen 

Turkey 

Pr HAMZAOGLU Azmi 

United Kingdom 

Pr O’BRIEN John P* 

USA 

Dr ALBERT Michael 

Dr BECKNER Mark 

Dr BITAN Fabien* 

Dr BONASSO Christian L 

Dr COX Curtis 

Pr FARCY Jean-Pierre* 

Dr HOFFMAN William 

Pr IBRAHIM Kamal 

Dr JALLO George 

Dr JONES Eric T* 

Dr KNAPP D Raymond 

Dr LANGE David 

Dr LAW JR Melvin 

Dr LEONE Vincent J 

Dr LOWE Robert W 

Pr MARGULIES Joseph 

Dr MUNSON Gregory 

Dr PARK Kee 

Dr PHILLIPS Jonathan 

Dr PINO Wilbert 

Dr REZAIAN SM 

Dr RODGERS William* 

Dr SCHNEIER Michael 

Dr SCHWAB Frank 

Dr SHARF Howard 

Dr SWANK Michael L 

Dr TAYLOR Brett 

Dr ULLRICH Christopher* 

Dr VELISKAKIS Kostas P 

Dr/Ing WARDEN Karen E* 

Dr WILES David* 

Pr WOLF Alon 

Dr ZERICK William R* 

* Full members being entitled to sponsor 


2004 new members 

Roberto Bassani, MD 

Orthopaedic and Spine Surgeon 

IRCCS Policlinico Universitario 

“San Matteo” - Pavia ITALY 

robertobassani@hotmail.com 

Thami Benzakour, MD 

Orthopaedic and Trauma Surgeon/Spine 

Director of Zerktouni Orthopaedic Clinic 

Angle Bd 9 Avril & Bd Abdou 

20100 Casablanca MOROCCO 

t.benzak@menara.ma 

Pierre Bernard, MD 

Clinique Saint-Martin 

Allée des Tulipes 

33608 Pessac FRANCE 

pb@cad-fr.com 

Former student of Pr Sénégas (University 

Hospitals of Bordeaux, France) and of Pr 

Dubousset (Saint-Vincent de Paul 

Hospital, Paris, France), Dr Bernard did 

most of his training and clinical practice 

at the Hôpitaux de Bordeaux from 1985 

to 2000. Since 1999 he has a private 

practice is spine surgery with Centre 

Aquitain du Dos, Clinique Saint Martin. 

Mark Beckner, MD 

8701 Maitland Summitt Blvd 

32810 Orlando (FL) USA 

Michel Biedermann, MD 

Orthopedic and trauma surgeon 

Main activity : Trauma, Children, Spine 

Hôpitaux de la Ville de Neuchâtel 

2000 Neuchâtel SWITZERLAND 

pir-bie@bluewin.ch 

Giuseppe Bonfiglio, MD 

Head of CTO 

Hospital Spine Surgery Dept 

Via Bignami 

20126 Milano ITALY 

giuseppebonfi@tiscalinet.it 

Carlos Botella, MD, PhD 

Head Division Neurosurgery 

Hospital General Universitario de Alicante 

Pintor Baeza, s/n - 03010 Alicante SPAIN 

cbotella@neurocirugia.com 

Dr Botella graduated in Medicine and 

Surgery at the Medical School of 

Valencia (Spain) in 1978. He did his 

Neurosurgery residency in Hospital La 

Fe (Valencia, Spain) from 1982 to1987 

and earned his PhD “cum laude” at the 

Medical School of Valencia (Spain) in 

1993. Since 1995 he is the head of the 

Neurosurgery Division at the General 

Hospital of Alicante (Spain). 

Sebastian Charosky, MD 

Orthopeadic Surgeon 

Institut Calot, Secretariat Rachis 

54 rue du Dr Calot 

62608 Berck FRANCE 

scharosky@hotmail.com 

Dr Charosky graduated with honours 

from the university of Buenos Aires. 

Former Resident of the Dupuytren 

Institut in Buenos Aires, Argentina. He is 

a member of the Groupe d’Étude de la 

Scoliose and of the Argentina 

Orthopeadic Association He is now 

working as a fellow in the Calot Institut, 

in the Spine Surgery Department 

directed by Dr Daniel Chopin. 

Oreste Ciaudo, MD 

Ortopaedic surgeon 

40 boulevard Victor Hugo 

06000 Nice FRANCE 

dr.ciaudo@wanadoo.fr 

Dr Ciaudo did his training at Pitié 

Salpétrière with Pr R Roy-Camille and 

has working in private practice in 

orthopaedic surgery of the spine since 

1983. He earned a Doctorate in Anatomy 

and in Law and is currently working as an 

expert for the Court. 

Curtis Cox, MD 

Neurosurgery-Spine Specialists Inc. 

1705 Christy Drive Suite 201 

65101 Jefferson City (MO) USA 

William Hoffman, MD 

1155 Dunn Road 

63136 St Louis (MO) USA 

Dennis Raymond 

Knapp Jr, MD 

Nemours Children’s Clinic 

Division of Pediatric 

Orthopaedic Surgery 

83 West Columbia Street 

Orlando, FL 32806 USA 

rknapp@nemours.org 

Dr Knapp graduated the Medical School 

at the West Virginia University in 1981. 

He did his residency in Orthopaedics at 

the West Virginia University from 1981 

to 1986 and he was a fellow in Pediatric 

Orthopaedics at theOrlando Regional 

Health-Care System from 1986 to 1987. 

Melvin D. Law, MD 

Spine, Reconstructive Spine 

Surgery & General Orthopaedics 

Centennial Medical Center 

Physicians Plaza 

2400 Patterson Street Suite 300 

37203 Nashville (TN) USA 

tnspine@aol.com 

Dr Melvin D. Law did his medical school 

training at the Medical College of 

Virginia, Richmond and 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 

NASS, the AAOS, 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. 

Gregory O. Munson, MD 

Spine Surgeon 

Jewett Orthopaedic Clinic, PA 

2876 South Osceola Avenue 

320806 Orlando (FL) USA 

Dr Munson graduated the Medical 

School at the University of Missouri in 

1975. He was a spine fellow at the 

Southern Illinois University in 1981. He 

works with Jewett Orthopaedic Clinic, 

P.A. since 1982. 

Wilbert Pino, MD 

10131 W. Forest Hill Blvd 

33414 Welington (FL) USA 

Jean-Patrick Rakover, MD 

Centre de Chirurgie Vertebrale 

Clinique du Pré 

13 av René Laennec 

72018 Le Mans FRANCE 

j-p.rakover@wanadoo.fr 

From 1984 to 1991, Dr Rakover did his 

internship in several hospitals in France, 

among which Pitié Salpétrière Hospital, 

Paris, with Pr R Roy-Camille and Saint 

Vincent Hospital, Paris, with Pr J 

Dubousset. He graduated the Medical 

School at the Université Paris VI in 1991, 

then he was a Chief Resident in 

Ortopaedic Surgery with Pr R Roy- 

Camille at the Pitié Salpétrière Hospital 

in Paris. Dr Rakover is the author of over 

25 scientific papers, presented and/or 

published in national and international 

meetings and journals. 

surgical internship at the New England 

Deaconess Hospital, Boston, 

Massachusetts from 1992 to 1993 and his 

Orthopaedic Residency and was a Chief 

Resident at the Massachusetts General 

Hospital, Boston, Massachusetts, within 

the Harvard Combined Program, 

from1993 to 1998. From 1998 to 1999 he 

was a fellow in spine surgery in the 

Department of Orthopaedic Surgery of 

Thomas Jefferson University, 

Philadelphia, Pennsylvania. 

Howard Sharf, MD 

4000 Park St. N 

33709 St Petersburg (FL) USA 

Manolis Tsafantakis, MD 

41 Agia Paraskevi 

15343 Athens GREECE 

Thomas Patsiaouras, MD 

Orthopaedic Surgeon 

Asklepeion Hospital 

Vas. Paulou 1, Voula - Athens GREECE 

thomaspa@hol.gr 

Jonathan H. Phillips, MD 

Practices: Nemours Children’s Clinic 

Orthopaedic Division 

83 W. Columbia Street 

Orlando, Florida 32806 USA 

jphillips@nemours.org 

Dr. Phillips attended St. George’s 

Hospital Medical School at the 

University of London in London, 

England. He did his residency in 

Indianapolis, Indiana USA and a 

fellowship in Pediatric Orthopaedics with 

the Gillette Children’s Hospital in St. 

Paul, Minnesota USA and the Shriner’s 

Hospital for Crippled Children in 

Minneapolis, Minnesota USA. Dr. 

Phillips has been practicing in Pediatric 

Orthopaedics for 11 years. 

Francois Du Toit, MD 

MB ChB, M Med (Orth) (Pret) 

Consultant Orthopaedic Surgeon 

Rotorua Hospital, 83 Mountain Road 

Rotorua Rotorua NEWZEALAND 

devon15a@xtra.co.nz 

Dr Du Toit is a member of the South 

African Spine Society, South African 

Orthopaedic Association, AO Alumni, 

NEW ZEALAND Pedicle Club. 

Brett A. Taylor, MD 

Assistant Professor of Orthopaedic 

Surgery Adult Spine Specialist 

Washington University 

School of Medicine, Department of Orthopaedic 

Surgery One Barnes 

Jewish Hospital Plaza, Suite 11300 

63110 St. Louis, Missouri USA 

Dr Taylor graduated the Harvard 

University Medical School, Boston, 

Massachusetts in 1992. He did his 

Konstantinos 

Zachariou, MD 

Director of Scoliosis & Spine Unit 

Saint Paul’s Kat Hospital 

Nikis 2, Kifisia 

Athens 145 61 GREECE 

kzax@hol.gr 

Dr Zachariou has been involved into the 

Nationwide School Screenings and 

Research on Scoliosis and other spinal 

deformities since 1976. Among other 

achievements, i.e. design, manufacturing 

and clinical application of orthopaedic 

braces, he is the first user of 

transpedicular screws for spinal fixation 

in Greece in 1988. Dr Zachariou is a 

member of AAOS, ESS, EFORT, NYAS, 

AASS, ARGOS, HAOST, CHOS and the 

author of more than 200 announcements 

and publications in major National and 

International Meetings and Scientific 

Journals. 


A classification of biomaterials 

Training 

A Classification 

of Biomaterials 

– Yves Debacker 


About… 

… Yves Debackaer 


(Clinical & Regulatory Affairs) 

Yves Debacker 

earned his PhD in 

Pharmaceutical 

Sciences and in 

Biochemistry and he 

also graduated the 

IAE of Lille, France 

in Business Management. He 

worked as an International Project 

Manager, General Manager and 

consultant for well known Drugs 

and Biomedical devices 

manufacturers. He was an 

international project manager for 

Bristol Myers Squibb holding and 

its subsidiary Zimmer, where he 

was in charge of clinical and 

regulatory affairs for bone 

substitutes. He also developed the 

collagen based range of 

biomaterials for Sofamor Danek 

where he was the general 

manager of the drugs and 

biomaterials subsidiary. 

… 

The term “Biomaterials” can be used broadly to encompass all 

materials that can be safely implanted into the human body. In 

common parlance, however, “biomaterials” are defined more 

narrowly and exclude metallic biomaterials, such as titanium or 

stainless steel, even though they are intensively used for 

implants. Historically, the first developments in biomaterial 

science consisted of finding a good biomaterial and testing its 

bio-compatibility, then trying to find as many applications as 

possible for that material. Nowadays biomaterials are custom 

designed to address a specific, precisely formulated need. This 

see change was caused by two factors. Firstly, technological 

progress has allowed customization of material production. 

Once materials could be reliably manufactured, the attitude 

toward their use evolved with phenomenal rapidity. The need for 

biomaterials is as old as time, but the explosive growth in the 

last three decades is derived from these changes in production 

and attitude. Wood and ivory were found in Egyptian mummies 

but, until recently, one could not refine the chemical properties 

of material. Once the first modern biomaterials were developed, 

health care professionals began to more clearly define their 

needs. The ability to design the products coupled with a more 

demanding clientele has produced the wide range of options 

currently available. 

THE PURPOSE of this article is to offer a general 

classification system for biomaterials. By codifying a 

classification system, we can better understand the best uses 

of specific products. For the purposes of our discussion, the 

main classification of biomaterials will derive from their 

resorption properties ; all these materials will thus be divided 

into resorbable or non-resorbable. 

Non-resorbable Biomaterials 

Alumina ceramics, bio-glass produced from silica salts, 

polymers (PEEK-polyetheretherketone, carbon fibres, PEpolyethylene, 

PMMA-polymetacrylate) are the most 

commonly used non-resorbable biomaterials. In spinal 


Training 

A classification of biomaterials 

surgery, the materials have been fashioned into 

interbody cages and spacers. Others have been 

used for bone replacement, such as the use of 

alumina ceramics for vertebral body 

replacement after corpectomy. 

Resorbable Biomaterials 

The resorbable biomaterials may be 

further divided into two classes : active 

and passive biomaterials. 

The resorption phenomenon at its most basic 

level is a chemical interaction between the 

biomaterial itself and the cells of the host. 

Passive biomaterials are materials that allow 

tissue development and tissue ingrowth inside 

the material network. The newly created tissue 

will then be integrated into and resorbed by 

the tissues around. This category includes most 

of the currently available biomaterials : 

• Bio-polymers : either natural (collagen, 

hyaluronic acid, chitosan, etc) or synthetic 

(PLLA, PGA or a mixture of both) 

• Resorbable ceramics (HAP-hydroxyapatite, 

TCP-tricalcium phosphates, BCP-biphasic 

ceramics) and phosphocalcium cements. 

These materials can be bio-chemically 

engineered to address different needs. For 

example, PLLA can be fashioned into resorbable 

interbody cages, while some other polymers 

(like hyaluronate) have anti-adhesion 

characteristics and may be used to reduce perineural 

adhesions. Hydroxyapatite and tricalcium 

phosphate have long been used for bone 

replacement. Phosphocalcium cements, as new 

and growing products, have been produced to 

act as an injectable viscous putty to fill bone 

voids. 

Active biomaterials directly act at the tissue or 

cellular level. These products release a chemical 

meditator that causes differentiation of 

precursor cell lines. Any material that has a true 

bio-chemical impact on tissues or cells is 

considered an active biomaterials. 

Active biomaterials may also be used as a carrier 

for therapeutic agents into the body. The 

biomaterial will, in this case, serve as an inert 

matrix into which the active agent - hormones, 

antibiotics, oncologic material - is infused and 

from which the material will be released into the 

body. 

Combinations of various biomaterials 

also hold great promise. Take for 

example, polylactic acid (PLLA) 

which is easily resorbable but is not 

osteo-conductive and, when 

resorbed, may induce fibrosis instead 

of bone formation. By adding a 

ceramic which is osteo-inductive but 

less resorbable, a material can be 

produced that yields a bone-forming 

resorbable composite. 

The border between active and 

passive biomaterials has become 

quite indistinct. Few of the newer 

products are either purely passive or 

active. As an example, researchers 

have recently shown that ceramics, 

which should be totally inert 

(passive), can induce slight bone 

formation (active) when implanted 

into muscle. This blurring of 

boundaries has led to a 

subclassification of biomaterials based 

on the activity of the individual 

chemical components of the product 

rather than of the material as a whole. 

Currently, spinal surgeons use 

biomaterials as fillers for bony 

defects, extenders or augmenters of 

graft materials, and as stabilizing or 

reconstituting frameworks for 

vertebroplasty. Devices and implants 

such as interbody cages have also 

been produced from biomaterials. 

Active biomaterials are currently 

being used as growth factors or antiadhesive 

agents for specific surgical 

indications. 

Newer trends in bio-material 

research are focussing on the 

development of autologus bone cell 

lines that form bone itself after reimplantation 

in the body and may 

help to repair or replace severely 

damaged body parts. The frontier of 

this research remains ever-changing 

and the potential limitless. ● 

… He also worked for Merck 

Biomet and for Boerhinger 

Mannheim as a biomaterials 

engineer and he was Clinical and 

Regulatory Affairs vice president 

for Europe for Regeneration 

Technology, a tissue bank based in 

California, USA, manufacturer of 

grafts for orthopaedic surgery. 

Among his clients, we may cite 

WRIGHT CREMASCOLI, DEPUY, 

LINK, HOWMEDICA ; SOFAMOR 

DANEK, FMS, KASIOS, 

ARTHREX ; EUROSURGICAL, 

ISOTIS, REGENERATION 

TECHNOLOGY, BIOBANK, 

TUTOGEN, BIOMET ; SPINE 

SOLUTIONS, ABS, LINKSPINE, 

STRYKER BIOTECH, ORTHOVITA. 

Today he is also an associate 

professor in Biomaterials at the 

Lariboisière - St Louis School of 

Medicine, Université Paris 7. Yves 

Debacker is member of numerous 

scientific societies, acting in the 

field of biomaterials : GESTO 

(groupe de recherche sur les 

substituts tissulaires osseux - 

research group on bone tissue 

substitutes), GRIO (groupe de 

recherche et d’informations sur 

l’ostéoporose - research and 

information group on osteoporosis), 

GRIBOI (groupe de recherche sur 

les biomateriaux injectables - 

research group on injectable 

biomaterials), AETB (association 

européennes des banques de 

tissus - European association of 

tissue bank), AATB : American 

association of tissue bank. ● 

Contact information : 

13 Gravier du robinet 

59117 Werdicq Sud FRANCE 

TEL+33 (0)3 20 39 28 60 

Fax+33 (0)3 20 39 03 79 

yves.debacker@orange.fr 


Agenda 

Training 

ISCAS-8th Annual Conference of the 

International Society for Computer Aided 

Surgery 

June 23-26, 2004 - Chicago, IL USA 

www.cars-int.de 

State of the Art in Chronic Low Back Pain 

April 4-6, 2004 - Bodrum TURKEY 

www.vitalmedbodrum.com 

BritSpine 2004 III 

Combined Meeting of British Scoliosis Society, 

British Cervical Spine Society, Society for Back 

Pain Research, British Association of Spinal 

Surgeons 

April 28-30, 2004 - Nottingham ENGLAND 

www.qmc.nhs.uk/britspine 

2004 POSNA Annual Meeting 

April 28-May 1st, 2004 - St Louis, Missouri USA 

www.posna.org 

Advanced Techniques in Spinal 

Decompression & Fixation 

April 16-18, 2004 - St Louis, MO USA 

http://pawslab.slu.edu 

NASS Spring Break : Innovations in Spine Care 

April 22-24, 2004 - Boca Raton, FL USA 

www.spine.org 

55th Annual Meeting of the German Society 

of Neurosurgery (DGNC) 

1st Joint Meeting with the Hungarian 

Neurosurgical Society 

25-28 April 2004 - Cologne GERMANY 

www.dgnc.de 

Bone Summit : The Clinical Science of 

Making New Bone 

May 13-15, 2004 - Cleveland, OH USA 

www.clevelandclinicmeded.com 

IOF World Congress on Osteoporosis 

May 14-18, 20004, Rio de Janeiro BRAZIL 

www.osteofound.org 

Agenda 

Meetings of interest for spine surgeons 

and Biomechanics specialists 

ASIA, American Spinal Injury Association 

30th Annual Scientific Meeting 

May 14-16, 2004 - Denver, CO USA 

www.asia-spinalinjury.org 

6th European Trauma Congress 

May 16-19, 2004 - Prague Congress Centre 

CZECH REPUBLIC 

www.guarant.cz - www.trauma2004.com 

4th Annual AAOS/OTA Trauma Course : 

Current Management Concepts, Techniques 

and Practical Solutions 

May 20-23, 2004 - Phoenix, AZ USA 

www.aaos.org 

1st National Congress of the Romanian 

Society of Pediatric Orthopaedics and Trauma 

May 26-29, 2004 - Calimanesti, Caciulata 

ROMANIA 

www.sorop.ro 

Spineweek 2004 : 

Combined Meeting of Leading Spine Societies : 

International Society for the Study of the Lumbar 

Spine (ISSLS) - Spine Society of Europe (SSE) 

Cervical Spine Research Society European Section 

(E-CSRS) - Sociedad Iberolatinoamericana de 

Columna Vertebral (SILACO) - Sociedade 

Brasileira de Patologia da Coluna Vertebral 

(SBPCV) - Asia-Pacific Orthopaedic Association 

Spinal Section (APOA) 

May 30-June 5, 2004 - Porto PORTUGAL 

www.medicongress.com/spineweek 

International Research Society for Spinal 

Deformities Meeting 

June 10-12, 2004 - Vancouver, British Columbia 

CANADA 

www.interprofessional.ubc.ca/irssd 

The 10th Advanced Techniques in Cervical 

Spine Decompression & Stabilization 

July 30-Aug 01, 2004 - St Louis, MO USA 

http://pawslab.slu.edu 

New Techniques in Orthopaedics 

Aug 04-06, 2004 - Brisbane AUSTRALIA 

kevin@wickhams.com.au 

coralyn@wickhams.com.au 

Argos North America 2004 

August 6-7, 2004 - Nemacolin Woodlands Resort 

& Spa, Farmington, PA USA 

argosNA@argosna.org 


Interdisciplinary Neck Course 

Sept 10, 2004 - Helsinki FINLAND 

www.oerg.at 

3rd World Congress World Institute of Pain 

Sept 21-25, 2004 - Barcelona SPAIN 

http://wipain.org 

3rd SICOT/SIROT Annual International 

Conference 

26-29 September 2004 - Havana CUBA 

www.sicot.org 

TraumaCare 2004 

Oct 15-17, 2004 - Sydney, NSW AUSTRALIA 

www.traumacare2004.com 

19th Annual Meeting of the North American 

Spine Society 

Oct 26-30, 2004 - Chicago, IL USA 

www.spine.org 

5th World Congress on Low Back and Pelvic Pain 

Nov 10-13, 2004 - Melbourne AUSTRALIA 

www.worldcongresslbp.com 

Spine Surgery : Advanced Applications and 

Techniques 

Nov 19-21, 2004 - Rosemont, IL USA 

www.aaos.org 

SOFCOT (Société Française de Chirurgie 

Orthopedique et Traumatologique) 

Nov 09-12, 2004 - Paris FRANCE 

www.sofcot.com.fr 


Training 

Clinical case discussion 

Bone substitutes 

in 2004 

– Claude SCHWARTZ 

Founding president of Pro Biomateria group (GECO) 

Bone substitutes are frequently used in orthopedic and trauma 

surgery as an alternative or an additional adjunct to bone grafts. 

The use of biomaterials as yet another substitute has enjoyed a 

rapid development in the last few years. 

THIS GROWTH can be explained by two major problems 

with both autograft and allograft usage : the first one is the 

associated morbidity, as well as the volume deficiency of iliac 

autograft, a deficiency that is well recognized by spinal 

surgeons as they badly need it ; the other reason is the fear of 

a potential infectious contamination as well as the reported 

failures of allografts in some long term studies, which may be 

immunologically mediated. Some indications for the use of 

biomaterials are no longer in question, others are undergoing 

investigations and still much needs to be learned in this 

exciting field. Certainly, autologous bone graft is still the gold 

standard and it is obvious that we should not hesitate to use it 

when we have the possibility. From the time of its inception, 

in posterior spinal surgery, the articular processes and various 

resected bone fragments have been kept to be used as local 

autografts.Every user knows the associated complications and 

the morbidity of iliac autografts but it has been but seldom 

quantified ; publications on the subject are rare on this very 

well recognized subject. A recent meta-analysis [1] on 30 years 

(1966 to 1997) of publications in orthopedic surgery has had 

the merit to review the subject and the results were quite 

astonishing : there is no less than 49% associated morbidity ! 

These authors have thus listed these as residual problems 

which are far from being exceptions : 29% developed chronic 

pain at the iliac graft harvest level. There were cosmetic 

deformity or concern in 40% of the cases. Other problems 

consist of : 10% resultant hematomas, 1.2 to 1.7% infection 

rate, 5% hernias, fractures of the anterior iliac spine, and 

rarely injuries of nerves or arteries. Moreover, the quantity of 

the harvested cancellous graft is often far from desirable. All 

this has obviously encouraged many investigators to search for 

an alternative solution to the use of autografts. Allograft, which 

has recently come under even more scrutiny for possible 

infectious complication [2] , seems generally to have been 

adequately tried and tested for the past twenty years following 

the publications of our American and Canadian colleagues, 

Harris [3] , then Mankin [4] and Gross [5] . Like some of them who 

began at that time to use it in this indication (most often in 

cryo-preserved form) we observed that some ten years later 

some patients had iterative pseudarthrosis. During those 

revision surgeries, we found little traces of allografts 

remaining, both for cases with massive grafts and split grafts. 

This resorption phenomenon, which is sometimes almost 

complete has been shown to us during a meeting organized in 

Quimper : Lazennec and La Pitié-Salpêtrière team had shown 

disturbing CT scans of allografts which had became literally 

hollow over time. Unfortunately this fundamental work does 

not seem to have been published. Considering that this 

phenomenon is quite frequent and severe, it is likely to be 

immunologically mediated. Some authors like B Loty [6] , AA 

Czitrom [7] , MC Horowitz [8] and most of all GE Friedlaender [9] 

had mentioned this possible immunologic rejection. At that 

time, it was common to think that frozen bone did not lead to 

an immunologic reaction, and that respecting blood type 

compatibility would be largely sufficient. When we preformed 

biopsies of allografts in revision surgeries for pseudarthroses, 

we had the histological confirmation of our worries : there 

were still signs of bone necrosis in the remaining allograft, 

both in block or split, with a few spindly trabeculae of new 

bone (fig. 1). Incorporation or true fusion remained superficial 

and never exceeded 2 to 3 mm in depth, what we readily call 

surface osteo-conduction, instead of true incorporation. In the 

literature, there are but a few publications stating long term 

success of allografts, (i.e. after over ten to twelve years) Such 

1 

Histology of morselized allograft after 5 years (C SCHWARTZ, Colmar) 


w w w . a r g o s - e u r o p e . c o m 

PRELIMINARY PROGRAM : 

Session 1 : 

- Total vertebrectomty : when ? 

- Multimetastatic patients : what strategy ? 

Session 2 : 

- How to treat a recurrent tumor ? 

- When not to operate a metastatic patient ? 

Lectures : 

- New trends in treatment of tumors 

by radiotherapy 

- Complications during and after total 

“en bloc” corpectomy 

GUEST SPEAKERS TO INCLUDE : 

Stefano Boriani, MD 

ITALY 

Alan M Levine, MD 

USA 

John G Heller, MD 

USA 

Vincent Pointillart, MD FRANCE 

Antonio Martin Benlloch, MD SPAIN 

Katsuro Tomita, MD 

JAPAN 

ORGANIZING COMMITTEE : 

Pierre ANTONIETTI, MD 

Laurent BALABAUD, MD 

Philippe BEDAT, MD 

Jean-Paul FORTHOMME, MD 

Frank GANEM, MD 

Alain GRAFTIAUX, MD 

Mihai JIANU, MD 

Pierre KEHR, MD 

Christian MAZEL, MD 

Pr Wafa SKALLI, PhD 

Jean-Paul STEIB, MD 

Anca MITULESCU, PhD 

Alexandre TEMPLIER, PhD 

Richard TERRACHER, MD 

TH 

INTERNATIONAL AR 

“Pitfalls in spin 

THURSDAY 27 TH AND FRI 

MAISON DES ARTS ET MÉTIERS

GOS SYMPOSIUM 

al metastasis” 

AY 28 TH JANUARY 2005 

9 BIS AVENUE D’IÉNA PARIS XVI 

2005 STUDENT THESIS AWARD 

Rewarding the best thesis in spinal surgery or Biomechanics. 

The Argos Thesis Award recognizes outstanding medical 

and/or Biomechanics research targeting a contemporary clinical 

problem in the management of spinal pathologies. This 

award is open to all scientists having completed a PhD or PhD 

candidates at the end of their PhD program as well as to 

medical students for a Master of Sciencies Thesis or for a 

Medical School Thesis. 

Nominees must not have completed/defended their research 

work prior to November 2002. A cover letter specifying the 

candidate’s interest in being considered for the Argos Thesis 

Award, 2 copies of the final manuscript of the thesis (in the 

original language*) and 3 copies of a long abstract (in English), 

i.e. up to 5 pages, clearly presenting the nominee’s work and 

having the nominee as first or sole author should be submitted 

to the Argos Secretary Office no later than October 1st 2004 

(see also Instructions for long abstract presentation). 

The award decision will be based on the quality and originality 

of the research work, its potential impact on the management 

of spinal diseases, its clear and rigourous presentation. 

The awardee is expected to attend the 9th International Argos 

Symposium in Paris, next January and to deliver a presentation 

of the work recognized by the award (7’ oral presentation + 3’ 

discussion). 

The award includes a 1000€ prize, winner’s travel and accomodation 

expenses on the occasion of the 9th International Argos 

Symposium, publication of the long abstract in the European 

Journal of Orthopaedic Surgery and Traumatology (EJOST). 

Instructions for long abstract preparation : 

To prepare your long abstract please refer to the Instructions to 

Authors in the European Journal of Orthopaedic Surgery and 

Traumatology (EJOST). For more information, please visit 

Springer website www.springerlink.com 

*Depending on Argos Board members capacities of reading 

the original language, i.e. at least one Board member curently 

reads and speaks your language. For more information, please 

contact Marjorie Salé : 

marjorie@argos-europe.com 

CALL FOR ABSTRACT 

Electronic submission deadline September 1, 2004 

Submit to abstract@argos-europe.com or directly on the website : 

www.argos-europe.com/abstract.html 

Submission rules : 

• Abstracts must be submitted by September 1st, 2004. All 

abstracts received after that date will not be considered 

• Abstracts must be submitted electronically 

• Abstracts must be submitted in English 

• Abstract recommended format : 

- Title 

- List all authors associated with the abstract 

- Main headlines : 1) Introduction and purpose 

2) Material and Methods - 3) Results - 4) Discussion and 

conclusion - 5) References - 6) Acknowledgements 

- Presenting Author contact information (phone, fax, eMail 

address, mailing address) 

- Institutional affiliations 

- Abstracts should not exceed 500 words 

• Abstracts are reviewed by the members of the Argos 

Scientific Committee and will be read in “blind” fashion. 

• Argos will send notification of acceptance via eMail to the 

presenting author on or after November 22, 2004.


Training 

confirmation would be necessary and more and more 

questions are arousing on this subject. Heterologous grafts 

have been used ever since the 19th century, but very early 

after Ollier [10] showed the existence of immunological 

problems. Xenografts had a renewal of popularity in the 50’s 

when Maatz [11] and his collaborators Graf et Lentz in Germany 

developed a bovine bone of which they had removed a 

maximum proteins by a process of dissolution : it was the hour 

of glory of Kiehl’s bone, which was short-lived in front of 

clinical failures, more late but constant, because of the 

remaining organic fraction. Progress to improve the purity of 

xenografts enabled to improve the tolerance ; however there 

had never been a true integration [12] , even in interbody 

arthrodesis [13, 14] and our experience [15, 16] with a prepared bovine 

bone (Surgibone ® ), on about thirty cases in various 

implantation sites confirms it in every case (fig. 2, 3). To that 

substitutes because of their regular porous structure and 

interconnected internal architecture, not unlike the human 

bone. There is the Porites variety which was most successful, 

marketed under the name Biocoral ® after various treatments of 

purification and chemical transformations. This ceramic is 

composed of about 98% of calcium carbonate, and thus is 

different from the human bone, which contains much less. In 

our experience there must be a total absence of contact with 

an organic fluid, such as synovial fluid, which seems to be able 

to slow down and even stop the re-colonization by the 

recipient’s cells. This is what can more probably explain the 

failures, with sequestration and aseptic serous discharges, 

which have been described and published both in 

traumatology and in opening osteotomies in the superior 

tibia [18, 21] . On the contrary, in spine surgery good results were 

reported [22] (fig. 4). The good results obtained with all those 

above-mentioned substitutes are far from being constant ; they 

4 

Coral (Biocoral © postoperatively, after 1 year, 2 years and 6.5 years, in a cervical interbody graft (P KEHR, 

Strasbourg) 

2 

Bovine Xenograft (Surgibone © behind the anterior tibia tuberose after 7 years and in a femur length 

adjustment after 5 years (C SCHWARTZ, Colmar) 

3 

Histology of bovine xenograft after 5 years in a femoral cortical zone 

(C SCHWARTZ, Colmar) 

was further added the problem of bovine spongiform 

encephalitis with a potential risk of contamination still 

possible by the said non conventional contamination agents 

which has obviously eliminated the interest for those 

xenografts. The bovine bone turned into ceramics at high 

temperature is one of the natural ceramics that has been 

hardly used [17] . On the subject of ceramics from natural origin 

as another biomaterial substitute, the coral must be revisited. 

Formed from the skeleton of marine animals of which 

numerous species exist, some of them have been used as bone 

vary a lot both according to implantation sites and to the type 

of bone substance loss, in addition, of course, to the type of 

substitute itself. Two paths have been the most explored by 

this research, that of calcium phosphate ceramics, mainly 

synthetic, and that of phosphocalcic cements, still called ionic 

or hydraulic. Their integration in the skeleton is different ; as 

well as their indications. Phosphocalcic cements are very old 

since Dresman [23] at the end of the last century reported about 

ten cases of various bone filling with calcium sulfate, also 

called plaster of Paris. For some fifteen years they were 

subjected to very interesting works by various high level 

teams [24, 26] . Those cements have been introduced on the market 

only recently, with clinical experiences which are still very 

limited. They result from an acid-base or hydrolysis reaction 

depending on cases with formation of different crystals fit into 

each other. For those phosphocalcic cements, considering the 

experimental works and the first clinical results, whether there 

is or not an absence of general or topical toxicity, despite a 

certain acidity during the reaction ; there is no harmful 

exothermic reaction either ; this is a stoichiometric reaction 

which is therefore very sensitive to the presence of water or of 

various ions, which can disturb it and therefore make the 

properties of cement vary once the cement has set ; the 

directions for use must therefore be strictly followed and most 

of all we must avoid an implantation site that would be too 

liquid and that would slow down or even inhibit the setting, 

which means that the implantation site must be accordingly 

prepared. Those cements look likely to resorb gradually and 

be progressively replaced by bone, as they disappear, without 


Training Bone substitutes in 2004 

slowing down the usual bone callus formation. The resorption 

velocity depends on the cement solubility, which depends 

itself on the setting characteristics. Besides there is the 

possibility which is still theoretical to add antibiotics (or even 

other active principles) ; their sustained release could 

constitute a considerable contribution in some treatments, as 

that of osteomyelitis. Those cements require an 

extemporaneous preparation, which means that it takes time, 

variable in length according to the operating room 

temperature ; they also must preferably be injectable, so that 

they can be inserted by minimal approach in the site and must 

well conform to substance loss which are sometimes deep and 

rifted ; then they must harden within a reasonable time for 

intraoperative use and have sufficient mechanical resistance. 

Finally there is the cost issue which is more and more 

important in surgery. This poses a real challenge. Some of 

these cements have appeared or are currently appearing on 

the market with very precise indications.Thanks to their 

mechanical properties, those bone substitutes can be used to 

complete the osteosynthesis ; they can be likely to replace a 

loss of post-traumatic substance in site of cancellous bone 

tissue, to help stabilizing a standard osteosynthesis only ; they 

are not adhesive substance. The fracture by compression in 

extension of the aging wrist, the pushing down of cancellous 

tissue in some fractures of tibial plates and of calcaneum 

(fig. 5, 6) are probably good indications ; for the moment, they 

rely on the results of the first series that could have been 

published on the fracture of the wrist [27, 28] . Another indication 

5 

Fig 5 : Ionic cement (Norian SRS © postoperatively and after 3 years in the distal radius (C SCHWARTZ, 

Colmar) 

Fig 6 : Ionic cement (Eurobone © 6 weeks postoperatively in the calcaneum (C SCHWARTZ, Colmar) 

can be the filling by injection of small benign tumors (like 

chondromas of phalanxes) after curettage by a minimal 

invasive approach ; in such cases, the patient could resume an 

activity almost immediately without particular need for further 

protection or immobilization. Considering experimental 

studies, there is also the possibility to use an injectable cement 

in some cases of vertebroplasty ; if all problems of rheology are 

solved, such technique will obviously be more satisfying than 

the use of acrylic cement. Therefore we can imagine that they 

be used as complementary treatment in some traumatic 

fractures with loss of cancellous substance of the vertebral 

body, which will perhaps enable to lighten the different 

osteosynthesis constructs in proportion, thanks to the filling of 

6 

the void by a solid bio-active substitute. More recently have 

appeared suspensions in aqueous phase of different pure or 

composite phosphocalcic ceramics ; they are also injectable 

but have no mechanical property ; our first uses in filling of an 

aqueous hydroxyapatite suspension (Ostim 35) show an 

excellent tolerance of the product and a quick and good quality 

consolidation of opening osteotomies where we have used it. 

(fig. 7, 8). This use is still too recent and isolated to already 

draw conclusions. As far as synthesis phosphocalcic ceramics 

7 

Hydrohylapatite aqueous suspension (Ostim 35 © after one year in the proximal tibia, after osteotomy (frontal 

and sagittal Xrays). (C SCHWARTZ, Colmar) 

are concerned, they are most often the result of a very high 

temperature heating (over 1000°C or 1100°C), called fritting, 

of a slurry, suspension of basis powders with a pore forming 

material, whose sublimation leads to macro-pores forming 

(from 100 to 500 microns of diameter) indispensable to bioactivity 

; micro-porosity, which considerably increases the 

surface of exchange with biologic fluids, corresponds to the 

interstices between grains assembled by matter bridges 

between themselves, interstices remaining after fritting. So 

those ceramics are bio-active that means they directly react 

with biological fluids and neighbouring cells, and this occurs 

all the more so since they have an important surface of 

exchange. The first works [29, 30] are already quite old, resulting 

mostly from research in the field of odontology and maxillofacial 

surgery. The first clinical series in humans seem to have 

been Australian and Japanese authors [31] , quite rapidly 

followed by Daculsi, Passuti and their collaborators in 

France [32, 34] . Various publications, particularly from De Bruijn, 

[35, 37] 

Mainard and Frayssinet and their collaborators have 

focused on the relationship between physico-chemical 

characteristics and osteo-integration. For their part, Le Huec 

and Clément [38] published very interesting experimental 

results proving the use to the spot of radio-labeled calcium, 

component of the ceramic, for bone reconstruction in the 

rabbit, but the existence of bio-activity itself has been known 

for a long time [39, 40] . Osteo-integration of ceramics in human 

bone, without fibrous interface between recipient bone and 

substitute, or between substitute and restored bone, has been 

[41, 42] 

proven more recently on the basis of convincing 

histological results. The conclusion is that it probably occurs 

on the following mode (fig. 9, 10) : there is first a migration 

phase of monocytic cells or multinucleate cells at the material 

surface without any vascular or connective consequence. Then 

8 



Training 

9 10 

Fig 9 : First stages of the integration of bi-phased ceramics (Eurocer ® ) (HA) 

Fig 10 : Total integration of bi-phased ceramics (Eurocer © ). A relatively spongious bony tissue filled the 

ceramic (HA). The latter was fragmented by bone remodeling. Bone trabeculae penetrated within the 

ceramic structure. 

we observe a fibroblasts and vascular elements infiltration, 

forming a connective loosened tissue, in the pores. We then 

observed a osteoblasts differentiation at the ceramic surface 

and the synthesis of an extra cellular bone matrix on this 

surface constituting an immature bone tissue. Finally there is 

a remodeling of this immature bone tissue, and then a very 

progressive remodeling of the ceramic, both replaced with a 

mature bone tissue. This phenomenon could be visualized up 

to some 5 to 6 mm depth in the bi-phasic porous 

ceramic.There is today two main types of ceramics : the beta 

tricalcium phosphate and the bi-phasic ceramics ; the latter 

have a variable percentage of hydroxiapatite and of tricalcium 

phosphate and are increasing on the market. However beta 

tricalcium phosphate alone is still used [43, 46] . Saragaglia shows 

quite interesting x-rays on the long term about such use in 

tibia opening osteotomies, with a perfect integration, but with 

much less resorption than what was first expected and that 

could have been described 

by others (fig. 11). As in 

every use of synthesis bone 

substitutes, whatever the 

anatomical site, the respect 

of standard practice in 

orthopaedic surgery is still 

necessary : thus a good 

preparation is needed 

together with a meticulous 

cleaning of the recipient site 

11 

Tricalcium Phosphate (Biosorb © after 5 years in the 

proximal tibia, after osteotomy (D SARAGAGLIA, 

Grenoble) 

to be in contact with a living 

bone. Therefore all of the 

granuloma must be removed 

in a prosthesis 

pseudarthrosis ; ceramics 

have no osteo-inducer effect in man, contrary to what has been 

proved in the dog [47] . After that, scraping of this recipient bone 

must be performed, especially if it is stiff and sclerotic ; this 

can be performed either with the bur or with a rongeur, 

depending on the local status and the operating site ; some 

minimal-perforations can be performed with a very thin drill, 

all this to favour the “escaping” of bone cells which are meant 

to gradually colonized those ceramics, and up to a certain 

depth. They are used only as reconstruction material. The 

addition of various autologous bone fragments which have 

been found on the spot (bone fragments resulting from 

reaming, fragmentation of laminas and other articular 

processes, osteophytes or possible ossifications) constitutes a 

certain biological benefit. A group of surgeons of the GECO 

(Groupe d’études pour la chirurgie osseuse - Group of Study 

for Bone Surgery), the Pro Biomateria group, has drawn up a 

book of requirements (pore size, global porosity, chemical 

composition with respective rates of hydroxyapetite and 

tricalcium phosphate) for 2 new bi-phasic ceramics according 

to their daily use. The first one (Eurocer 400 ® ), in form of 

granules with a diameter of a few millimetres, has nothing 

really original and is like other ceramics of this type ; it has 

been used and is still used in every case of significant loss of 

bone substance in which a mechanical support was not 

needed ; the second one (Eurocer 200 ® ), presented under 

various forms (discs, cubes, sticks…) has a mechanical 

resistance in compression 

similar to that of the 

cancellous bone. This was 

quite innovative at the time. 

It has been progressively 

and cautiously used in cases 

with significant absence/loss 

of substance, with a size 

sufficient enough to receive 

a graft, and in which a 

mechanical contribution was 

also needed [48, 49] (fig. 12). 

12 

Oonishi [50] had opened the 

Reconstruction of a stage 4 cotyle in a 78 year old 

woman with bi-phased ceramic granules and blocs 

(Eurocer © , after 6.5 years (C SCHWARTZ, Colmar) 

way with a published report 

two years before on the use 

of pure hydroxyapatite in 

thin granules to press sealed acetabulums on it. In review of 

our radiological results, use of granules seems beneficial, as 

contributing to reconstruction material on the spot, along the 

osteotomies performed in the approach of femurs (and along 

intra-operative fractures which sometimes occur) in difficult 

revision surgeries of the femurs (fig. 13). Our results were 

13 

Reconstruction with bi-phased ceramic granules and blocs (Eurocer © of 2 femurs in an 83 year old woman, after 2 

years in the right femur and 3 years in the left femur (C SCHWARTZ, Colmar) 

confirmed by F Gouin [51] for the cotyle and by L Sedel [52] for the 

femur. From 1996, through the impetus given by P Lecestre, 

we have used ceramics in cases of significant loss of bone 

substance in traumatology [53] (fig. 14). Successful results have 

been obtained with regularity. The absence of complications 

characteristic of those substitutes explains that the indications 

rapidly expanded to some pseudarthroses, as well as to 

osteotomies and to benign tumors [53] . Other teams of 


Training Bone substitutes in 2004 

References 

14 

Reconstruction of a burst inferior femur with bi-phased ceramic granules (Eurocer © after 1 month on the left 

side and after 18 months on the right side (P LECESTRE, La Rochelle) 

investigators had a similar approach concerning synthesis 

[43, 46, 54, 55] 

calcium phosphate ceramics (fig. 15, 16). Finally, 

honour when honour is due, our Pro Biomateria team took of 

15 

Fig 15 : Bone filling after benign tumor resection with bi-phased ceramic granules 

(Triosite © after 5 years (F GOUIN, Nantes) 

Fig 16 : Bi-phased ceramic granules (Eurocer © in a proximal tibia osteotomy, after 2.5 years 

(P LE COUTEUR, St Herblain) 

course an instant interest in the applications of synthesis 

substitutes in spinal surgery : JP Rakover, E Laloux and G 

Gagna published their first results on a large series of posterior 

fusions [56] , JP Steib on interbody fusions [57] (fig. 17). Besides, 

spinal surgery was the first to be concerned [21, 33] in France by 

the use of ceramics in orthopaedic surgery. However this 

spinal surgery also poses the most problems of evaluation 

since imaging is still often difficult to interpret and therefore 

clinical results are the only true available criteria, in addition 

to a few histological results [42] after material removals ; 

However as years go by, according to Delecrin and a team 

from Nantes [58] , who have worked a lot on this subject, it seems 

that ceramics combined with bone found on the spot could 

safely and accurately allow to avoid a complementary 

autologous graft harvest (both in postero-lateral fusions and in 

interbody fusions). The evolution of 

technologies has allowed the finalization of 

various synthesis bone phosphocalcium 

substitutes, accurately, safely and 

progressively replacing anything that could 

have been used so far. In addition, 

iatrogenic complications of those 

substitutes do not exist due to the way they 

are manufactured and to their composition. 

Clinical results on the medium term (almost 

up to 10 years) seem encouraging ; for this 

reason it seems quite natural that they are 

gaining wider acceptance and are used 

more frequently. ● 

17 

Interbody fusion with bi-phased ceramic granules (Eurocer ® ) (JP STEIB, Strasbourg) 

16 

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communications devises used to foster 

the progress of research on the 

mechanosensory system in bone. The 

general phrase “mineralized tissue 

research” rather than the specific phrase 

“research on the mechanosensory system 

in bone” is used in the naming the 

website and describing these activities 

because it is believed that focus on the 

topic described by the specific phrase 

will actually involve almost all of the 

topics covered by the general phrase. 

The primary objective of this proposed 

communication activity is to create 

interest, a sense of community, and 

enhanced understanding in mineralized 

tissue research amongst all the 

participants, especially the involved 

graduate and undergraduate students. 

This will be achieved by assimilating 

information and making this information 

accessible and useful to national and 

international participants and researchers 

and the public at large. ● 

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Your website may be interesting for our 

readers. Please send the address to : 


Biomateria 

www.biomateria.com 

In September 2000 the new Biomateria 

site was launched, open to anyone with 

an interest in biomaterials, medical 

Bonenet 

www.bonenet.net 

This website is designed to foster the 

progress of research on the 

mechanosensory system in bone. The 

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Nacre as a European bone supplyschool 

Evaluation of surgery 

Nacre as a bone supply : 

basic data lead up 

to a promising alternative 

* Museum National d’Histoire 

Naturelle. Département des Milieux 

et Peuplements Aquatiques. USM 

401. UMR CNRS 5178. 7, rue 

Cuvier 75231 Paris cedex 05. 

** Département de Chirurgie 

Orthopédique, Clinique Jouvenet, 

Square Jouvenet 75016 Paris. 

*** CHRU de Fort de France. Sce 

de Chirurgie Orthopédique et 

traumatologique. BP 632 97261 

Fort de France Martinique Cedex. 

– Evelyne Lopez*, Pierre Antonietti**, 

Olivier Delattre***, Christian Milet*, 

Sophie Berland* 

About 10 years ago, mother-of-pearl or “nacre” 

was discovered to be bone biocompatible and 

basic studies (1, 2) have demonstrated the 

physiological conditions for their compatibility. 

Nacre and bone are both biogenic calcified 

compounds and both result from a 

biomineralization process in which mineral is 

deposited onto an organic matrix scaffold. 

IT IS WELL KNOWN that the bone matrix 

entraps molecules triggering bone 

regeneration. Nacre undergoes self-repair when 

damaged and this process also involves a cellular 

stimulation. Ongoing research reports the 

retrieval of like-proteins in the mineralizing 

matrix from distant taxa, not only for molecules 

involved in calcium binding, but also for those 

related to growth factors or cytokines. 

Consequently, these results support of the 

conservation of molecular signals for 

biomineralization control within the organic 

framework of biomineralized structures. Our 

working hypothesis is that the nacre matrix is a 

source for molecular signals that possess the 

ability to trigger bone cell commitment. Raw 

nacre bioactivity in bone systems was 

established by means of in vivo experiments. We 

used the mother-of-pearl inner layer of the shell 

of Pinctada maxima, a bivalve mollusk. The 

Pinctada nacre is composed of calcium 

carbonate crystallized in aragonite form on an 

organic matrix scaffold. 

The osteogenic activity of the nacre was 

investigated in the vertebral trabecular bone of 

sheep [3] . Cavities, 3mm in diameter, were 

prepared in the upper lumbar vertebrae via a 

posterior lateral extracanal percutaneous route 

(fig. 1a). Raw nacre, in powder form, was 

evaluated as an injectable bone void filler while 

the control cavities were left empty. The control 

specimens confirmed that the cavities were 

above critical size ; at 12 weeks, spontaneous 

bone healing was at a standstill and only a ring of 

new bone formation lining the edge of the cavity. 

A quiescent marrow lattice filled 62% of the 


Evaluation 

Nacre as a bone supply 

control cavities. The vertebral cavities filled with the nacre in 

powder form underwent a trabecular bone regeneration 

process and bone ingrowth occurred at the expense of the 

nacre (fig. 1b). Radiographic analysis showed that new bone 

formation was fully mineralized bone and subjected to 

remodeling, i.e., equivalent to normal, healthy bone (fig. 1c). 

The osteogenic effects of nacre were also evaluated in a rabbit 

model [4] . An intertransverse arthrodesis, between the fifth and 

sixth lumbar vertebrae, was performed with either autologous 

iliac crest bone or nacre powder mixed with autologous blood. 

The results indicate that Pinctada nacre can, like autologous 

bone, stimulate the formation of a bone bridge between the 

transverse processes of rabbit lumbar vertebrae. The spines 

implanted with nacre revealed bone between the vertebrae 

starting 5 weeks post-implantation. The nacre implanted at 

sites lacking stem cells or precursor cells led to endochondral 

bone formation (fig. 2). This suggests the release of active 

factors from the nacre as it dissolves leading to the recruitment 

and differentiation of fibroblasts from the connective tissue 

between the transverse processes to give rise to bone cells. 

In this experimental series, where nacre was used in powder 

form, bone ingrowth occurred at the expense of the nacre 

material. On the other hand, in a series of in vivo experiments, 

raw nacre pieces were designed for large bone defects and 

used as replacement bone devices in the femur of the sheep [5] . 

In this form, the nacre pieces showed a persistence in the 

bone without alteration of the implant’s general shape over a 

period of 12 months. However, there was surface microerosion 

at the edge of the nacre implant and new bone formation 

occured after implantation. Histological analysis showed that 

osteogenesis began within an intervening activated cell layer. 

Xray diffraction electron microscopy performed at the 

interface of the nacre and the recipient tissue characterized 

the initial step of osteogenesis to be a calcium and phosphorus 

rich layer, the elements of the bone mineral phase [6] . The 

complete sequence of osteogenesis resulted in direct contact 

between newly formed bone and the nacre, thereby anchoring 

the nacre implant (fig. 3). 

References 

1. E. Lopez, C. Milet, M. Lamghari, L. Pereira-Mouriès, S. Borzeix & S. Berland. 

The dualism of nacre. Key Engineering Materials, 2004, 254-256 : 733-736. 

2. P. Wesbroek, F. Marin. A marriage of bone and nacre. Nature 1998 ; 392: 

861-862. 

3. M. Lamghari, S. Berland, A. Laurent, H. Huet, E. Lopez. Bone reactions to 

nacre injected percutaneously in the vertebrae of sheep. Biomaterials, 2001, 

22 (6) : 555-562. 

4 M. Lamghari, P. Antonietti, S. Berland, A. Laurent, E. Lopez. Arthrodesis of 

lumbar spine transverse processes using nacre in rabbit. Journal of Bone and 

Mineral Research, 2001, 16 (12) : 2232-2237. 

5. O. Delattre, S. Berland, E. Lopez, Y. Catonné. La nacre : substitution du 

cartilage et de l’os Revue de Chirurgie Orthopédique, 1999, 85 (5) : 530. 

6. G. Atlan, O. Delattre, S. Berland, A. Le Faou, G. Nabias, D. Cot, E. Lopez. 

Interface between bone and Nacre implants in sheep. Biomaterials, 1999, 20 : 

1017-1022. 

7. L. Pereira, C. Milet, MJ. Almeida, M. Rousseau, F. Robichon, E. Lopez. 

Biological effect of the water-soluble matrix extract from the nacre of the 

bivalve mollusk Pinctada maxima on vertebrate cell proliferation and 

differentiation. Bone, 2001, 28 (5) : S249 

8. MJ. Almeida, L. Pereira, C. Milet, J. Haigle, M. Barbosa, E. Lopez. Comparative 

effects of nacre water-soluble matrix and dexamethasone on the alkaline 

phosphatase activity of MRC-5 fibroblasts. Journal of Biomedical Materials 

Research, 2001, 57 : 306-312. 

9. M. Rousseau, L. Pereira-Mouriès, M. J. Almeida, C. Milet, E. Lopez. The 

water-soluble matrix fraction extracted from the nacre of Pinctada maxima 

produces earlier mineralization of MC3T3-E1 mouse pre-osteoblasts. 

Comparative Biochemistry and Physiology A, 2003, 135 (2) : 271-278. 

Figure 1a : General image (scanning) of a sheep 

lumbar vertebrae showing the route of the bone void. 

Figure 1b : Microradiograph of an undecalcified 

section of a nacre injected vertebral cavity at 12 

weeks. New bone formation occurred within the bone 

void filled with the nacre powder (N). The bone foci 

formed at the expense of the nacre filling material. 

Recipient bone at the edge of the bone void (B). 

(magnification x25) 

Figure 1c : A higher magnification shows that new 

bone formation is subjected to remodeling. Numerous 

concentric bone-forming units are observed which, 

with remodeling, give rise to elongated trabeculae. 

Newly formed bone is being fully mineralized ; the 

Xray density is related to the degree of maturity of the 

mineralizing bone. (magnification x25) 


Nacre as a bone supply 

Evaluation 

We demonstrated that the nacre organic matrix is the source 

for the signal molecules responsible for bone cell stimulation. 

Recent cellular biology studies have shown that the 

dissolution products of the organic matrix of nacre control the 

stimulation of osteoprogenitor cells [7, 8, 9] . The water-soluble 

components of the organic matrix were extracted from nacre 

following a patented process ; no demineralization step was 

performed. In in vitro experiments, bone cells and bone stem 

cells were supplied with the extracted nacre water-soluble 

matrix. Bone cells cover a variety of phenotypes - we used the 

different mammalian cell types involved in bone regeneration. 

The cells were chosen to provide a set of osteogenic lineage 

from precursors to differentiated and mature bone cells. Bone 

marrow stromal cells, fibroblasts (MRC5 cell line), and 

preosteoblasts (MC3T3-E1 cell line) were supplied with the 

nacre water-soluble matrix extract. The commitment of these 

cells to bone formation was assessed by means of alkaline 

phosphatase activity and osteocalcin measurements. The 

effects of the nacre organic matrix extract were compared to 

those of well-known bone inducers, dexamethazone and BMP- 

2. The nacre organic extract induces the recruitment of bone 

marrow stromal cells and the maturation of osteoblastic cells 

up to the bone matrix mineralization phase. This effect was 

assessed by the increase in osteocalcin production, a specific 

marker of bone matrix mineralization in the cultures. 

Bone marrow cells, supplemented with the nacre organic 

extract, started to mineralize after 14 days of culture. 

Meanwhile, the osteocalcin level increased consistently, 

corroborating the maturation of the bone marrow cells into 

bone forming cells. 

The MRC5 fibroblastic response to the nacre organic extract 

treatment was an early increase in alkaline phosphatase 

activity when compared with the differentiating factors effects 

in the control groups. Alkaline phosphatase activity and 

osteocalcin measurements showed that preosteoblastic cells 

were induced to maturation, up to mineralization in MC3T3- 

E1 cultures. 

The organic matrix isolated from Pinctada nacre contains the 

signals responsible for bone cell commitment, e.g., the 

biological activity of the whole nacre that we observed in the 

in vivo studies. Indeed, this matrix acts, in particular, on bone 

cell recruitment and differentiation until the final step of 

mineralization. 

The nacre can provide a biomaterial basis for bone 

regeneration. For a biomaterial to be successful, bioactivity 

must be achieved. The objective in bone reconstruction is 

biomechanical quality of the newly formed bone and/or the 

bone provided by an implant. Implant fixation implies the 

need to obtain a strong bond while preserving physiological 

conditions and normal stress patterns. Failure of the interface 

integrity between host bone and a bone graft implant results 

in loosening and continues to be the leading cause of bone 

implant fracture. Our studies gave evidence that bone and 

nacre can form a hybrid interactive system, transient or 

sustained, because the durability of implanted nacre is shaperelated. 

Nowadays, biomaterials are not only dedicated to 

replace organs, they are required to have bioactive properties 

so that the self repairing capability of the tissue is stimulated. 

Nacre belongs to this generation of biomaterials. 

The mother-of-pearl from the Pinctada shell has proven to be 

a biomaterial that stimulates bone regeneration. Basic studies 

have shown that nacre is bone biocompatible and is a natural 

delivery system for signals inducing the bone cells and their 

precursors to take part in a healthy bone formation process. ● 

Figure 2a : Light microscopy of an histologic 

undecalcified section 11 weeks after arthrodesis using 

a nacre graft. Endochondral bone formation process 

occurred after nacre implantation. N = nacre, C= 

cartilage, B = bone. Toluidine blue staining. 

(magnification x16) 

Figure 2b : Contact microradiograph of a section at 

the arthrodesis site. Nacre particles (N) remain at the 

edge of newly formed mineralized bone in which bone 

trabeculae are organized around bone marrow spaces. 

(magnification x2). 

Figure 3 : Microradiograph of an undecalcified 

section of trabecular bone provided by a raw piece of 

nacre implant (N). One year after the implantation, the 

nacre implant is sustained. Bone ingrowth and 

remodeling occurred within the recipient tissue and 

trabeculae bridge the nacre implant. 

34 Argos SpineNews - N° 8 April 2004

Communication 

Litterature update 

Source PubMed - Keywords : biomaterials & spinal 

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Evaluation Biospacer ® 

With this in mind and in co-operation with Fin- 

Ceramica Faenza, we designed, produced and 

clinically tested a range of intervertebral spacers 

for the cervical spine. These spacers, 

made of Al2O3 Alumina with a 

bioactive coating (CE #0546), are 

designed to perform better in the 

most common clinical situations 

where interbody fusion is needed in 

the cervical spine. 

The shape of the implant has been 

designed to optimize immediate 

mechanical stability through alumina 

posts ; crevices and holes within the 

device facilitate bone in-growth and 

fusion. The advantages of the new 

device may be summarized thusly : 

BIOSPACER ® 

an innovative intervertebral Alumina spacer with a 

bioactive coating for the cervical spine surgery 

– N Francaviglia MD 

CM Laager PhD 

A Nataloni PhD 

Introduction 

The intervertebral spacers we designed to perform 

cervical fusions are made of Al2O3 Alumina with a 

bioactive coating and, compared to those currently 

in use, represent a step forward both in terms of 

design and materials. The particular shape of this 

new spacer has been designed using the finite 

element analysis (FEM*) in order to take into 

account the loads which the spacers will bear, and 

to plan to optimize the implants’ response to 

compression and flexion stress. 

* See Ceramica Acta, N°5/97, p. 5-13, 1997 

outstanding biocompatibility, 

anatomic and functional design, and 

proven bioactivity In this brief report, 

we present our results, at maximum 

follow-up of seven years, using this 

new device. 

Methods 

The Biospacer ® was designed based 

on a finite element analysis of the 

cervical spine from C1 to C7. After a 

thorough investigation of various 

available biomaterials we chose an 

Al2O3 ceramic (composed of crystals 

of Al2O3 with a polycrystalline 

structure) with a bioactive glass 

coating in a complete range of sizes. 

We chose the Al2O3 ceramic because 

the mechanical properties of the material are ten 

fold stronger than bone (after examination under 

the ISO 6474 Standard). The Biospacer ® has a 

About… 

… Natale Francaviglia 

Natale Francaviglia was born in 

Catania, Italy, in 1953. He 

graduated the medical and surgery 

school cum laude and published 

his thesis on 

“Coiling and kinking 

of the internal 

carotidis” in 1977. 

From 1980 to 1981 

he specialized in 

Neurosurgery. 

(Specialization thèsis on 

“Myelopathy due to cervical 

spondylartrosis”). He practiced as 

a neurosurgeon in several 

Neurosurgery departments in the 

world : Amsterdam, Upsala, 

London (with Professor Crockard), 

Hanover (with Professor Samii), 

Washington (with Professor 

Sekhar). From 1991 to 1996 he 

was a professor of Neurosurgery 

at the University of Genova. Since 

2000, he is the Head of the 

Neurosurgery department of 

Sant’Elia Hospital in Caltanissetta, 

Italy. 

Dr Francaviglia performed more 

than 1600 surgeries in Genova and 

about 800 in Caltanissetta, and 

published almost 100 scientific 

papers and book chapters. ● 


Biospacer ® 

Evaluation 

micro-porous surface (manufactured using a 

proprietary technology) with pores of 0.05-0.06 

microns with a grain dimension of 2-5 microns. 

This microscopic architectural configuration 

optimizes coating with the bioactive glass and 

facilitates bony in-growth (fig. 1). The bioactive 

glass is derived from silica and sodium and 

calcium phosphates. Its ceramic properties have 

been modified in the microcrystalline phase to 

enhance bioreactivity during chemical bone 

resorption and reconstitution. At a chemical 

level, the goal is to activate immediate ionic 

exchange between the coating and the adjacent 

bone to produce an autologous hydroxyapatite 

and thus form an active bone-implant interface. 

Surgical procedure 

The surgical technique utilized is the standard 

anterior microscopic decompression facilitated by 

the use of the Caspar distractors. After preparation 

of the fusion bed, stainless steel trials are used to 

determine implant size. The Biospacer is then 

implanted and compressed. Fluoroscopy is used to 

confirm position. In multi-level procedures, an 

anterior cervical plate is applied. Postoperatively, 

patients wear a Philadelphia cervical collar for 8 

weeks (fig. 2). 

The follow-up period ranged from 3 months to 7 

years (with an average follow-up of 42.3 months 

and a standard deviation of ± 27.8 months). 

Cervical anterior-posterior and flexionextension 

lateral radiographs were obtained at 

two, six and twelve months after surgery (fig. 3a 

& 3b). Computerized tomography was obtained 

at six and twelve months. 

Fig 3a - Check CAT patient treated at one level 

Fig 3b - Check CAT patient treated at two level 

Results 

One hundred and two patients were treated 

with the Biospacer, six were lost to follow-up. In 

the remaining 96 patients, successful fusion was 

achieved in all cases. Implant stability was 

observed in all cases with no evidence of 

subsidence of any of the implants. Follow-up 

radiographs confirmed maintenance of the 

lordosis achieved at surgery and the CT scans at 

six and twelve months demonstrated bony ingrowth 

into the pores and bonding of the bone to 

the implant surface. 

Complications 

None. 

Patients groups 

Between 1996 and 2003 the senior author has 

treated 102 patients with a total of 144 

Biospacers ® implants. 64 of the procedures were 

at one level, 33 at two levels, 4 at three levels 

and 1 at four levels. Patients were operated for 

degenerative or traumatic cervical pathologies. 

70 were men and 32 were women. Patients’ ages 

ranged from 35 to 73 years with a mean age of 52 

years : 

Pathology 

Disc extrusion 

Trauma 

Spondylosis 

Pseudarthrosis 

Patients treated 

50 

16 

35 

1 

Conclusion 

This brief article reports our experience with the 

Biospacer ® for anterior cervical fusion at followup 

out to seven years. The three dimensional 

architecture of the implant facilitates immediate 

stability. The high compressive strength of the 

microporous alumina ceramic is a prerequisite 

to implant survival over the thousands of motion 

cycles that the cervical spine undergoes on a 

daily basis. Finally, the active bioglass coating 

enhances osteointegration of the spacer. Based 

on the long-term postoperative results, we 

believe our technique of interbody fusion is safe 

and effective. The use of the implant has 

eliminated the need for autogenous graft (and its 

incumbent morbity) and provided reliable 

fusion with preservation of cervical lordosis. The 

Biospacer ® not only acts as a spacer for 

reconstructing the defect left by decompression 

but also serves as a scaffold on which the fusion 

mass can be laid down. ● 


Communication 

Interview with C. Ray 

Interview with 

Charles Ray 

“ 

When I was 9 years old, I knew that I wanted to be a doctor 

and my father, who was an engineer, also wanted me to be an 

engineer. I was also very mechanical ; at age 11 or 12, I could 

take a clock apart, then put it back together and it would work. 

Mechanical aptitude is something outside of education and 

intelligence. It is a set of skills that not everyone has. Today, I 

know of surgeons who are great thinkers but who are not 

mechanically so capable. They cannot help it because they do 

not have the same cerebellum. Anyway, I ultimately became 

involved in the field of spine work through my training in both 

neurosurgery and engineering. Approaching engineering, I 

started in physics, then became involved in engineering 

activities, then I did some graduated work in engineering 

during the time that I was a resident in neurosurgery. When I 

went to the Mayo clinic, for a graduate program in 

neurophysiology, a program was started between the Mayo 

clinic and the University of Minnesota in bio-engineering. I was 

one of the four students. Later, I taught a course in engineering 

as applied to medicine for the Clinic Staff. Organizing this 

course, which I later also gave after I went on the staff at Johns 

Hopkins Medical School as well as in Switzerland, forced me to 

put all such thoughts in proper perspective. As a result, I 

ultimately published a very large book on the principles of 

medical engineering. 

When I was 9 years old, I knew 

that I wanted to be a doctor… 

” 

interested in bio-engineering and others. Several were very 

creative people, like Vladimir Zworykin, who invented the 

television tube and camera. His brother was the founder of 

RCA (Radio Corporation of America). A Canadian friend, John 

Davis initiated the International Institute of Bio-Engineering 

based in Paris. We established a journal, with an international 

membership. This group formed a basis for further societies, 

but as industry became involved everything changed. More 

importantly, once the US-FDA (Food and Drug Administration) 

became involved in 1978, things really changed. While a fellow 

in the Mayo clinic I was given a key to the machine shop, since 

I was already a skilled machinist. Working there in the evenings 

1 2 

* Diversification of medical devices - from laparoscopy to electric stimulation 

My involvement in bio-engineering began in 1958, quite early, 

so I had the chance to meet several others who pioneered this 

field. There were NASA people, astronauts, professors 

Fig 1 : Drawing of a stereotactic brain instrument, affixed to the skull of a patient. The orientation components 

are visualized on Xray films and adjusted to reach the desired target. A hollow guide pin is drilled and driven 

into the skull and a narrow electrode probe inserted through it afterwards. Electroencephalographic 

recordings are made from the multicontact probe to localize foci of epileptic discharges prior to brain 

resection to stop the seizures. This device system was the only surgical device ever manufactured and sold in 

IBM. A component of the system is in the Design Collection of the Museum of Modern Art in New York City. 

Fig 2 : Drawing of the instrument of figure 1 attached by nailing to the skull, showing the orientation adjusted 

to reach the deep brain target (point 40). The probe length was then chosen. 



Communication 

I developed and prototyped a brain stereotactic machine and 

deep brain diagnostic electrodes which later became the only 

medical devices ever manufactured and sold by IBM. A 

component of this system is in the design collection of the 

Museum of Modern Art in New York. A small number of the 

systems were sold, but with FDA controls coming along, it was 

too complex and expensive to prepare all the documentation, 

that is, too expensive for a small marketed device, so it was 

abandoned. 

At John Hopkins, in Baltimore, I began to work on my book of 

1300 pages, entitled “Medical Engineering”, published in 1974 

but is now available again in offprint. This reference and 

teaching book details the entire field of medical engineering ; it 

required seven and a half years to finish, mostly while I lived 

and worked in Switzerland. 

Hoffman-La Roche, the pharmaceutical giant, became interested 

in diversifying into medical devices. A scout came to one of our 

meetings of the International Society of Bio-Engineering and 

asked me if I would come to Basel start this diversification in 

medical devices. I had never worked in industry. When I was at 

the Mayo Clinic I met Earl Bakken the founder of Medtronic. 

Thus, when I went into industry in Switzerland, Earl came to me 

and invited me to come and work with him at Medtronic. At that 

moment, I felt that I had a moral commitment to continue in 

Basel as long as it would be successful. I found that working in 

Switzerland was somewhat difficult. Many Swiss are interesting 

and personable people but from a business point of view they are 

difficult. So, after five years, having had considerable 

interference with upper management I felt the need to move on. 

At Roche I unsuccessfully proposed a variety of potential 

projects. One proposal in 1968, long before anyone else thought 

about it was instrumentation for laparoscopic surgery. But they 

expressed no interest in working on “gadgets”. Another long term 

project was the development of in vivo chemistry, using special 

solid state electrodes and fiber optic reflection/absorption 

spectroscopy to do wet chemistry inside the body. Some of these 

concepts are now slowly coming from other laboratories. The 

problem I had was many of the projects were away before their 

time and therefore speculative. We did, however, develop solid 

state oxygen electrodes and for measuring lactic acid levels in the 

arterial circulation of the body, which turned out to be a very 

good way to predict impending shock. After it was clear that the 

majority of these long-term projects were of no interest there and 

Earl Bakken had come again to ask me to come to Medtronic to 

start a diversification for them, I agreed. The diversification I 

started at Medtronic, now the world’s largest medical device 

company, made use of adapted cardiac pacemaker 

instrumentation to stimulate nerve tissue for pain and motion 

control. So the TENS units as well as peripheral nerves 

stimulators, vagus nerve stimulators, spinal cord stimulators, 

deep brain and cerebellum stimulators were used for pain and 

also for the control of abnormal movement and ultimately for 

epilepsy. 

“ 

…the major cause of chronic 

disabling pain in North America 

was bad surgery of the spine… 

” 

These devices all started in my department there. Later I told 

Mr. Bakken that the development of the implantable pulse 

generators based on heart pacemaker technology had reached 

the point where there was nothing major left to be done. 

However, most important then was to find the targets in the 

body in which the electrodes should be placed, and to adapt the 

electrodes and pulse forms to best perform the stimulation. 

Thus the pressing need was for clinical applications. He agreed 

and I started a neurological rehabilitation institute in 

Minneapolis. It soon became obvious that the major cause of 

chronic disabling pain in North America was bad surgery of the 

spine and the use of oil contrast media for spinal myelography. 

These had the problems of nerve root injury and the potential 

for producing adhesions in the intradural space and its 

contained nerve tissue. These problems led to terrible pain 

conditions having little chance for cure. So we developed 

electrodes and targets for stimulation of the various nerve 

tissues which effectively blocked the pain sensations, giving 

relief in most cases. This Institute for Low Back and Neck Care 

in Minneapolis was begun together with a young neurosurgeon 

Charles Burton who had formerly been a resident of mine when 

I was on the faculty of John Hopkins. This institute was started 

in 1982, and is still prominent after 21 years. It is one of the 

original multidisciplinary spine institutes of the world. We had 

three neurosurgeons, three orthopaedic surgeons, three nonsurgeons 

and several certified physician’s assistants in our 

practice. That’s when I learned more about fusions, also 

learning to be dissatisfied with fusion technology in use at that 

time, 1986-1990. This was interbody fusion with bone alone, 

which did not work very well. Because of my engineering 

background, I worked on different methods such as 

approaching fusion through the facets joints then into the disc 

space. The method proved to be both hazardous and too 

difficult for surgeons to learn, however. 

When I attended the NASS (North American Spine Society, my 

being one of its founders) meeting 1987 in Canada, Doctor George 

Bagby gave a lecture showing the use of a perforated tubular 

device that he called “baskets” to create fusions in the necks of 

horses, I suddenly realized that if this basket were threaded, like 

3 4 

Fig 3 : Photography of Ray-Threaded Fusion Cages (TFC), developed and patented by the author. Over 

200,000 of these fusion devices have been successfully implanted in the USA and many countries of the 

world, without the need for additional instrumentation, pedicle screws, etc. 

Fig 4 : Drawing by the author showing the placement of Ray-TFC devices into the intervertebral disc space to 

promote a fusion. 


Communication 


bone had been described by a Spanish surgeon friend, Ortero-Vich 

of Cordoba, Spain, then I would have a fusion cage. Thus, I 

developed the Ray threaded fusion cage, the instrumentation for it 

and the surgical technique. It has since been used in about 300 000 

people around the world. However, after working with the cage for 

five or six years, I again decided that there had to be something 

additional for chronic, disabling disc pain. 

“ 

The fusions, although they serve 

well in selected cases, are not the 

best solution for many spine 

problems 

” 

For the last 16 or more years I had been doing intensive studies 

on the biology and pathology of the human intervertebral disc, 

beginnning at a time when few others were seriously studying 

the disc and its nucleus, except for investigators, like Jill Urban 

of London, and Gosh who had published a book on the biology 

of the disc, and a few others. From an engineering point of 

view, I assumed that the nature of the annulus depended upon 

the nature of the nucleus that in turn depended upon the nature 

of the endplate. And understanding this combination was the 

real approach that led to the development of a replacement for 

the disc nucleus. 

Fig 5 : Drawing of the new Prosthetic Disc Nucleus (Ray-PDN) placed into the emptied disc nucleus cavity to 

replicate the normal function of the nucleus, restore mobility and height of the disc space and relieve back 

pain. These devices (now inserted in about 3000 patients in 37 countries) ; are implanted in a dehydrated 

condition ; they then draw in water and swell, filling the emptied nucleus cavity, lifting and tightening the 

surrounding fibers of the outer disk annulus, restabilizing the spine segment. They are used to prevent postdiscectomy 

collapse with latent degeneration and to remove the necessity for a rigid fusion at selected spinal 

levels. A cervical spine version is also being developed. This easily implanted device may well replace the 

need for most spinal fusions and total artificial discs in the future. 

When the vertebral endplate is damaged or degenerated with 

age, the normal transmission of nutrients through it to the 

nucleus is largely finished. This loss of transport of nutrients 

into and anerobic waste products removal out of the nucleus is 

why the nucleus degenerates. The normall swelling of the 

nucleus hydrogel tightens and stabilizes the annulus. When the 

nucleus degenerates, much like letting the air out of an 

automobile tire, the tire (like the annulus) deflates, buckles, 

delaminates and fails. This prosthetic disc nucleus (PDN) had 

to be made of an inert hydrogel with considerable swelling 

power that did not depend upon endplate transport. This 

realization led to the development of the PDN, requiring about 

sixteen years. A key component was finding a proper polymer 

About… 

… Charles Dean Ray, MD 

Charles dean Ray, MD, MS, FACS, FRSH was born in 

Americus, Georgia, USA, Aug 1, 1927. He earned his A.B. in 

Pre-med Sciences, in Physics, at Emory University, Atlanta, GA, 

in 1950, and his M.S. with Honours in Experimental Physics at 

the University of Miami, in 1952. He was in charge of graduate 

courses in Bioengineering at the Christian Brothers Col., 

Memphis, & the Univ. of Minnesota, Mayo Clinic. Later on, he 

also graduated with honors the Medical College of Georgia, 

1956. 

From 1956 to1957, he was a surgical Intern, then from 1957 to 

1962 neurosurgical resident at the Semmes-Murphey Clinic, 

Baptist Memorial Hospital, Memphis. In 1960 he became a 

Research Associate, Director of Neurosurgical Research Lab, 

University of Tennessee, Memphis, and from 1962 to 1964 he 

was also a Fellow in Neurophysiology and Course study & 

Lecturer in Bioengineering at the Mayo Clinic and Foundation. 

From 1964 to 1968 he was an Assistant Professor of 

Neurosurgery, Lecturer in Bioengineering, Director of the 

Neurometrics Laboratory, John’s Hopkins University and 

Hospital, Later on he moved to Switzerland and then Chief of 

Department of Medical Engineering, Corporation Vice-Dierector 

F. Hoffman-LaRoche & Co and also a visiting professor and 

Lecturer in Bioengineering, Bürgerspital, Univ. of Basel, 

Switzerland. He collaborated with Medtronic, Minneapolis, and 

acted as a Corporate Vice-President for almost 7 years (1972 - 

1979), and later on as a Senior Consultant (1979-1992), Neuro 

Division, being very much involved in the medical research. By 

the same period he was a Clinical Associate Professor in 

Neurosurgery at the University of Minnesota (1972-1982), 

Industry Rep. Advisory Panel on Neurology Devices, U.S.Food 

and Drug Admin, Washington, DC, (1975-1979), Editor-in-Chief, 

Medical Engineering, (1968-1974). and Medical Progress 

Through Technology (1970-1980), member of the Editorial 

Board, Medical Instrumentation, and other similar journals. 

From 1975 to 1982 he was the Chief of the USA Delegation for 

Neurosurgical Devices, ISO (International Organization for 

Standards). 

From 1980 to 1996 he was a President and Chairman of the 

Board for CeDaR Surgical Inc. and Senior Director, Spinal 

Neurosurgeon Institute for Low Back & Neck Care, Minneapolis, 

member of the Board of Directors (1977-1997), Herman Miller, 

Inc. (Fortune 500 Company), Zeeland, Michigan. Just after, in 

1996, he became the Director of Research & Development for 

the Spinal Research & Education Foundation, Norfolk VA until 

1999. He is also Past President and First chairman of Board for 

the North American Spine Society. Today Dr Ray acts as a 

neurosurgeon in the Medical Staff at Sentara Hospitals, (Norfolk 

General, Leigh Memorial), Norfolk, VA, he is the President of the 

American College of Spine Surgery, member of the Board of 

… 



Communication 

… Directors, American Board of Spine Surgery, Director 

Emeritus, Spinal Neurosurgeon, Institute for Low Back & Neck 

Care, Minneapolis MN, Senior Member of the American 

Medical Association, American Association of Neurological 

Surgeons & Congress of Neurological Surgeons, Senior Life 

Member, Institute of Electrical and Electronic Engineers, Board 

member for Spine-Health.Com, Chairman Emeritus & Medical 

Director, RayMedica Inc., Minneapolis, President InveRay, 

Ltd.Yorktown, VA, Member of the Board of Directors, A.A.M.I. 

Foundation, Chairman of the Committee on Materials and 

Devices, World Federation of Neurosurgical Societies, Editorial 

Reviewer for SPINE 

Member of the Joint Section of Spine & Peripheral Nerves, 

AANS/CNS, member of the Editorial Board and Publications 

Committee for the North American Spine Society 

President of the International Spinal Arthroplasty Society, 

member of the Amerercian College of Physician Executives, 

National Associate Member of The Oriental Institute, University 

of Chicago, and Archaeological Institute Of America. 

He is also a visiting professor in over 25 countries around the 

world. He was also the nominee of several prestigious honors : 

Distinguished Alumnus, Medical College of GA, 1994. Leon 

Wiltse Award (research and leadership in spinal surgery) NASS 

1997. Alpha Omega Alpha (Honor Medical Society) 

Sigma Xi (Science) 

WHO’S WHO in : The World, America, Midwest, Frontiers of 

Science, Science & Engineering, and Biomedical Engineering, 

American Men and Women of Science 

Cosmos Club (Washington, D.C.) 

Wisdom Society Honoree 

Recipient “Golden Spine Award” 1985. Pres. Discretionary 

Award, Medical College of GA,’53 

Bausch & Lomb Scientific award, Tech. High School 1945. For 

the design of the PDN (Prosthetic Disc Nucleus), he received 

the Gold Prize for the Most Important Medical Device Design of 

2000. Charles D. Ray published over 350 papers, including 2 

books on medical engineering, 1 on spinal surgery, 6 

monographs, 52 US & over 100 foreign patents, 2 device 

standards, many special reports, audio-visuals & original papers, 

abstracts or chapters. 

His works cover various fields, such as : neurosurgery, spinal 

surgery, clinical neurophysiology, medical business, health care 

administration, clinical engineering, psychometrics, research & 

development, medical/surgical materials & devices, medical 

ethics and regulatory control of med. devices. ● 

which would behave like the nucleus ; then we had to find a 

way to contain the polymer, the surgical technique to implant it 

and so on. Interestingly enough, there were no polymers 

available which would (1) hydrate rapidly under pressure, (2) 

allow for daily fluctuation in height in order to pump the 

nucleus juices through the endplate and (3) have the expansile 

ability to lift the disc space, when the normal force on the disc 

can be as much as 1.8 times the total body weight. This is a very 

large pressure distributed over a small surface area. So finally 

we modified a biocompatible polymer so that it could perform 

these tasks. 

“ 

The molecular construction of the 

nucleus tissue cannot be imitated. 

” 

The means to achieve these functions is to permit the hydrogel 

to absorb water from surrounding tissues, while bearing the 

pressure. We found that if the polymer is manufactured so that 

it is in planar layers, therefore anisotropic, then under pressure 

while it is absorbing water, the layers slide apart and the 

height, therefore the volume of the prosthetic nucleus 

decreases. I have a patent on this expansile behavior. This 

change in height from day over night, performed by the normal 

nucleus tissue behaves opposite to our prosthetic nucleus, 

because when the normal nucleus absorbs water it increases in 

height, which could not be imitated by polymers, and still 

under pressure, fluctuate or pump. The molecular construction 

of the nucleus tissue cannot be imitated. It is too complex, a 

strange material, able to exchange free water under changes in 

presure, functioning in a strange way unlike any other 

hygrtoscopic material in nature. Even the animal nucleus 

material is different, being more fluid, more oil like, not having 

the same lifting power, which is not needed in quadrupeds. On 

finally developing the polymer pellet to be implanted, having 

the lifting power we needed, it was too rigid and if we 

increased the water content to soften the pellet before it was 

inserted it was too big. So we had to learn how to control the 

polymer size versus hydration so that even though we increased 

the hydration, promoting a faster hydration after implantation, 

the height was reduced ; no easy task. The trick here was to 

subject the layered partly hydrated polymer pellet to higher 

pressure during manufacturing before being implanted in the 

patient. Achieving these goals was almost like black magic, 

because there was no science that led us to it - only trial and 

error. 

“ 

Material science generally is almost 

like black magic 

” 

One almost cannot predict how metal alloys will behave so one 

must make trials. Material science generally is almost like black 

magic. Polymers and co-polymers are largely the same. Indeed, 


Communication 


so is the pharmacokinetics of pharmaceuticals. We were 

fortunate to have stumbled into the right combination not 

because we were so very smart but because we were very 

persistent. And now the PDN device is working remarkably 

well, better than I had ever expected. We have now implanted 

more than 2000 cases in 36 different countries of the world. 

This is why I travel a lot, to perform demonstrative surgery in 

these countries. We have a great research, development and 

professional marketing team that has made these effects come 

true. Every good project has to have a good team. 

I do not know of anybody more fortunate than I am, with these 

opportunities at this stage of science and by staying focused on 

the spine. Indeed, I feel that God has blessed me immensely. 

“ 

…it takes experience to know what 

not to do… 

” 

I knew Prof. Roy Camille, a real genius in spinal stabilization. 

I do not perform scoliosis surgery, and do not appreciate or 

have need for long segment fusion, which present completely 

different biomechanical problems. The lumbar spine and much 

of the thoracic and cervical spine use short segment fusions. 

Arthur Steffe and Leon Wiltse are close colleagues and I used 

several of their devices and methods, interfacing as well with 

practically every surgeon of note in the spine field. It’s been a 

wonderful opportunity that will not come again because these 

pioneers are mostly gone. Today’s spine pioneers are involved 

in other things, particularly in spine arthroplasty. These giants 

include Karin Büttner Janz, Thierry Marnay, Hansen Yuan, Hal 

Mathews and others, plus several internationally famous 

surgeons who perform these methods with good clinical 

success. They are all members of the latest group of young 

lions, although none of us is very young anymore ; clearly, it 

takes time and experience to know what not to do. Classical 

training primarily teaches us what we should do, but it is only 

at the operating table and in a clinical environment that we 

learn what we should not do and what we cannot do ; these are 

equally important things that guide us. 

destruction of structural mechanics. So, to preserve anatomy 

and biology of a joint and not destroy it mechanically, leads to 

the concept of arthroplasty ; to repair the function of the disc, 

although not necessarily the structure. In a word, it is to 

stabilize without pain and without fusion. One of the clever 

things in medicine is knowing, in devices as in pharmaceuticals, 

what can be done functionally that does not necessarily appear 

the same structurally. This is like automobiles, which do not 

resemble covered wagons but they accomplish the same things. 

I think that the next target is to go after the source of the 

problem, to affect the endplate. It is the endplate that regulates 

or controls the biological and physiological behavior of the 

nucleus, which then affects the behavior and the structure of 

the annulus. So, when the endplate becomes sick or damaged, 

at the present time the result is irreversible. This is why I do not 

trust the idea of tissue transplants, genetic manipulation, 

cloning and the like to replace a sick nucleus, as long as the 

endplate is sick. One cannot improve the technique of warfare 

unless the supply lines are working. Therefore the project for 

the future is to heal the endplate. However, we do not fully 

know why normal endplates become damaged. At the present 

time there is no way to reverse most of the many degenerative 

processes. We do know that cigarette smoking damages 

endplates, some of the vasoactive drugs may damage them, but 

we otherwise have limited knowledge of what affects them, 

other than trauma or collapse. So the competition to develop 

proper arthroplasty devices arises not from existing devices, 

per se, but from knowledge in the field of biology, its 

physiology. My friend, Doctor Bob Mulholland, from 

Nottingham, England, an editor of the Journal of Bone and 

Joint Surgery, feels very strongly the same. Typical in science, 

when we run to the end of our knowledge we must circle back 

to study the fundamentals. ● 

“ 

… the competition to develop 

proper arthroplasty devices arises 

not from existing devices, per se, 

but from knowledge in the field of 

biology, it’s physiology … 

” 

None of us is endowed with the power to predict the future. We 

can only predict trends ; the trend is now towards the 

preservation of anatomy and restoration of physiology without 

6 

Fig 6 : Drawing of a surgical kneeling frame for spine 

surgery, attached to the end of a standard operating table. 

Fig 7 : Drawing showing a patient in the kneeling position on 

the operating platform of Figure 3. On the back is a sterile 

'ring' that holds a variety of essential devices, such as 

retractors and illuminators used during surgery. Several 

additional patents detail these ancillary devices. 

7 



Training 

In early 2001, she underwent a T6-S1 posterior fusion. The 

construct consisted of pedicle screws at T6-9, L1-3 on the left. 

There were screws at T6-9 on the right. For unclear reasons, a 

short rod was employed on the left at L1-3 with pedicle 

screws. No instrumentation was performed of L4, L5, or S1. 

Iliac bolts were placed bilaterally. 

Within six months the iliac bolts disconnected from the rods. 

The patient developed progressive loss of ambulatory ability, 

right leg radiculopathy, and severe, unrelenting back pain. She 

was unable to stand, sit, or lie comfortably. Two years after 

surgery, she sought an opinion from another surgeon. 

On examination, both ankle jerk reflexes were absent, straight 

leg raising on the right produced pain at 30°, and, on standing 

she pitched forward unto her walker. The distal ends of the 

rods were palpable through the skin, and stuck out like sticks 

when she stood up. 

Clinical 

case 

discussion 

Case presentation : 

The patient is an 82 yo female who initially underwent a 

decompressive laminectomy from L3-5 in 1997 (at age 76). 

About one year later, she developed severe back and leg pain 

and radiographs showed an unstable spondylolisthesis of L3-4. 

She was treated with an instrumented L3-5 postero-lateral 

fusion. Her pain initially improved but then she developed a 

recurrence of low back and bilateral radicular pain in 2000. By 

report, CT-myelography showed stenosis above her fusion. 

At the time of my evaluation, radiographs revealed 

displacement of the iliac bolts from the rods and an unstable 

listhesis of L3-4. 

She was treated surgically with anterior discectomies and 

interbody fusions at L2-3, L3-4, L4-5. Vertebral body screws 

were placed anteriorly at L2, 3, 4. On the same operative day, 

the posterior hardware was removed and a reconstruction was 

performed with pedicle screws bilaterally at T6, 7, 8, 9, L1, 2, 

3, 4, 5, and S1. Divergent sacral alar fixation was also 

employed. 

Currently, she is 8 months after surgery and walking with a 

cane. She has rare right leg discomfort and occasional back 

pain relieved by anti-inflammatory medicines. 

– W.B. Rodgers, MD 

Spine Midwest 

Jefferson City, MO, USA 

82 years old female : 

2 years TLS fusion 

Hardware failure at 6 months post-op. 

Revised anterior and posterior. 


Training 


Case comment 1 : 

“ 

From the history it transpired that this lady at the age of 80 

underwent posterior stabilization from T6 to the pelvis for 

spinal stenosis cranial to a previously decompressed and 

stabilized spine (L3 to L5). 

The initial construct appears unusually long and with rather 

poor caudal fixation. In addition there appears to be an amount 

of sagital imbalance. This explains the failure of this long 

construct. It was interesting to note that the rod disconnected 

rather than the iliac bolts cut out. The revision has nicely 

addressed the sagital imbalance and distal fixation 

insufficiency. 

Nevertheless I still find this construct rather long. One could 

have perhaps considered during the previous (i.e. 2001) 

surgery limiting the stabilization to the decompressed level(s) 

taking into account the age of the patient. Alternatively one 

could stop at T10 or T11. 

Such long constructs in the elderly can be a problem. 

Pseudarthrosis is not uncommon and implant loosening is a 

major concern. In fact Zurbriggen et al* reported their long 

term experience in 40 patients with degenerative scoliosis 

(slightly different setting) treated surgically and noted that in 

half of them they had to remove the metalwork on average 4 

years later due to painful loosening. One would hope that the 

addition of anterior fixation limits this problem. I have to 

admit that I would personally hesitate to offer front and back 

same day surgery to a 82 year old lady. If the penultimate 

fixation was limited to L2 one might have got away with it for 

a couple of years… 

* Zurbriggen C. Markwalder TM. Wyss S. Long-term results in patients treated 

” 

with posterior instrumentation and fusion for degenerative scoliosis of the lumbar 

spine. Acta Neurochirurgica. 141(1):21-6, 1999. 

– Dr Constantin Schizas MD MSc Orth FRCS 

Médecin Associé 

Hôpital Orthopédique de la Suisse Romande, Lausanne SWITZERLAND 

(former Consultant Spinal Surgeon Whittington Hospital, London UK) 

Case comment 2 : 

“ 

The case presented hereafter is strange. Why strange ? 

Because we do not know the diagnosis and the indication. We 

suppose it is an anterior imbalance, i.e. camptocormia, due to 

muscular deficiency. 

Why strange ? Because the spinal instrumentation with a great 

lever arm is bound to be dismantled and a single point of 

rod/screw fixation into the sacro-iliac joint has to maintain the 

whole spine and the head. This assembly together with the 

obvious absence of anterior bone graft explain why it was 

bound to be dismantled. The high lumbar instrumentation, 

through which the long rod is not inserted, supposes that the 

deformation was important in the thoraco-lumbar area. As a 

French former student of Mister Roy-Camille, on one hand I 

am surprised by the audacity of the surgeon who inserts 

screws in the high thoracic spine, on the other hand I don’t 

understand his prudery concerning the lack of implants in the 

low lumbar spine. 

On a 82 year old patient, the bone is never of exceptional 

quality, therefore the spine has to be multi-instrumented to 

obtain a solid fixation. The mobility is important as shown on 

the selective Xrays. Morover there is certainly an extensive 

pseudarthrosis. The deformation may therefore be considered 

as being flexible. A posterior surgery would probably solve the 

reduction problem but an anterior surgery will have to solve 

the stability issue. 

First, a posterior approach with removal of the 

instrumentation should be performed, cleaning of the spine, 

opening of all articulations and posterior osteotomies if 

needed. Then the spine should be re-instrumented keeping 

the same screw holes (larger diameter) and of course 

multiplying the fixation points in almost each instrumented 

vertebra in staggered rows. The sacral fixation will have to 

include a pedicular, alar and iliac fixation. A posterior graft and 

the rods will then be inserted. 

Once both rods have been inserted and the implants closed 

but not tightened, the bending of both rods must be 

performed at the same time, around each lumbar screw, one 

after the other, which will allow for a good restoration of the 

patient’s lumbar lordosis, by means of repeated maneuvers all 

along the spine. Then the anterior approach should be 

assessed. 

It seems obvious that the posterior surgery on a 82 year old 

patient is already a great challenge, but it will remain fruitless 

if an anterior intervertebral support is not put forward. This 

anterior surgery could be performed on the same day or a few 

weeks after. The approach will be at best video-assisted with 

small incisions but will have to include the whole lumbar part 

from T12 to S1 or even a little higher than T12. The graft could 

be composed of bone substitutes and cages could be used but 

they might sink into this soft bone. Once the graft is solid and 

if the sagittal balance 

” 

has been restored, the patient will be 

Ok. Good luck ! ● 

– Professor Jean-Paul Steib 

Hospital Physician - Spinal surgery, Hip and foot surgery 

Hôpitaux Universitaires de Strasbourg 

Hôpital Civil, Strasbourg FRANCE

8th International Argos Symposium p12 - ArgoSpine

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