Argos SpineNews 2

April 2001

News from the world of Spinal surgery and biomechanics

Focus on :

The spine engine :an original theory on human locomotion

A new bipedicular implant

TIM-C : a laboratoryfor the 3rd millenium

Medical applications ofshape memory alloys

Interview with Pr FrançoisLavaste - Part 2

NEW Technologiesin Spine SurgeryNEW Technologiesin Spine Surgery

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

Interview with Pr. François Lavaste : what is biomechanics? 8

Readers Forum 14

PRAXIMInterview with Mr Stéphane Lavallée 19

Fifth International Argos Symposium: A Spine Odyssey 24

Agenda 29

Web review 50

Interview with Professor S. GracovetskyThe Spine Engine 33

OMNI-AXIAL Connector 40

Retrospective study on medical applications ofshape-memory alloys 42

Mrs. Jocelyne TroccazTIM-C Laboratory 15

Orthopaedic Surgery & Robotics at theTechnion’s Robotics Lab 47

Evaluation

Communication

Training

April 2001

News from the world of Spinal surgery and Biomechanics

SSuummmmaarryy

communicationWhat Biomechanics is ?

8 ARGOS SpineNews N° 3- April 2001

Who are the Frenchbiomechanical engineers?

I think that the physiologist SimonBouisset is a major figure in the field ofmovement analysis, while Comolet wasa famous biomechanical engineer in thefluid biomechanics field. When he died,this whole branch of biomechanics wasalmost orphaned. Finally, JoannesDimnet represents an important figurein the field of osteoarticularbiomechanics.

What have been the main phasesin the history of the LBM?

The LBM was created in 1972, but itonly really became a truly structuredlaboratory after 1979. In 1985, the teamof scientists, formerly working in theUniversity of Paris XII, invited us toparticipate in a DEA (postgraduatetraining programme) that they had set

up in 1981. They suggested that weinclude a biomechanics specialty in thisdiploma. Our collaboration with theCNRS (Centre National pour laRecherche Scientifique) (FrenchNational Scientific Research Center)started in 1996 and was formalized in1998. One year later, LBM was grantedCOFRAC quality certification, which issomewhat an exceptional situation for aresearch laboratory. Very fewlaboratories have obtained this type ofaccreditation. I think only two CNRSlaboratories have been granted thisaccreditation.

Is it true that Raymond RoyCamille contacted you personallyto propose a researchcollaboration?

Yes, when he came to propose this work,he was head of the department oforthopaedics of Poissy hospital in thewestern suburbs of Paris. About oneyear later, he was appointed head of thedepartment of orthopaedics at Pitié-Salpêtrière hospital. Thus, we becameneighbours, geographically, but he haddeveloped his approach at a time whenwe were not at all involved in this field.Our subsequent collaboration greatlyfacilitated all of our efforts. Our meetingwith Jean Dubousset and the Sofamorcompany was a second important step inthe history of the LBM. This happenedin 1988, i.e. when Mrs Skalli joined ourteam. In fact, our collaboration withSofamor was initiated by Guy Viart, whowas Chief Executive Officer at the time.I think he asked us to present ourbiomechanical activities dedicated tothe spine at Rang du Fliers, in the north

of France.

How did this collaboration withmanufacturers start?I think this collaboration started as a theresult of interventions by clinicians, whoinitially came to LBM for postgraduatetraining in biomechanics. When theysubsequently questioned the variouscompanies supplying them with theirproducts and were unable to find asolution to their problems, theysuggested that the manufacturerscontact ENSAM. This circuitconstituted a major step in thedevelopment of the LBM. Whenclinicians and manufacturers came toENSAM to validate their mechanicalideas, we advanced from a highlyintuitive field to a much more objectivefield.

What was Guy Viart contributionto this development?

He is obviously one of the leadingfigures who developed this link betweenthe LBM and industry. In reality, thislink is actually an association betweensurgeons, manufacturers and researchlaboratories.

Would it be conceivable for otherspecialties to be involved in thisassociation?

This association is already spreading toother areas. We need the skills of amaterials specialist to solve problems ofwear, and a biocompatibility specialist,i.e. a chemist. We will also need amechatronician (combination of

Interview with Pr. Franç

what is biomechanics?This third issue of Argos SpineNews includes the final part of the inter-

view with François Lavaste. After defining the field of biomechanics andafter briefly describing the history of the prestigious laboratory that he

manages, François Lavaste hereafter explains why the LBM is situated atthe crossroads of science, medicine and industry.

Stereoradiography - a 3D medical imaging

technique (Collaboration study: LBM

ENSAM Paris - ETS, Ecole Polytechnique

Montréal)

mechanics, electronics and dataprocessing) as we intend toprogressively install systems inside thehuman body that could be controlledfrom outside the body (see article onnanotechnologies ARGOS SPINENEWS No. 2). Consequently, we are nolonger dealing with mechanics alone,but mechanics plus electronics, plusdata processing and materials.Biomechanical engineers are obliged tocomplete their research teams with thecontributions of other specialists.

Would you say that this processconstitutes an additional step inthe evolution of biomechanics?

Yes, these changes are clearly illustratedby the collaborations in the field ofimaging. We obviously need to give ashape, a geometry to our mechanicalobjects and our models. Imaging wasinitially standardized, but now there is agrowing trend towards personalization.In the longer term, imaging will alsoprovide us with information aboutmechanical characteristics. This is whythis type of collaboration is so important.

The LBM stands at thecrossroads between science andindustry.I would even say that it is at thecrossroads between science, industryand clinical practice.

While visiting your website, wenoticed that you place particularemphasis on the concept of amultidisciplinary approach. So

how is your research organizedwithin the LBM?In relation to the concept of amultidisciplinary approach, I would saythat two basic disciplines are associated:orthopaedics and mechanics. Each ofthese disciplines then uses certaincomplementary skills. For example,imaging in the case of orthopaedics.Sometimes our work is conducted incollaboration with surgeons specializedin vascular systems. On the mechanicalside, we need computer programmersand automaticians. Certain skills beyondthe field of mechanics must be added.

What are the current relationsbetween the LBM and the worldof surgery?

I think we have two sorts of relationswith the sphere of surgery. Firstly, wehave relations in the field of training, aswe have trained almost 150 surgeonssince 1985, who now form a networkthroughout France, and thus we have a

contact in almost every teaching hospitalin France. For example, in the East ofFrance, we collaborate with ProfessorJ.P. Steib, and, in the South-West, withProfessor J.M. Vital. I especiallyremember the first batch of graduates in1985.

Do many surgeons still want topursue this training?

Yes, there is a strong demand on the partof clinicians, but we can only accept tensurgeons per year. This is certainly not agreat number each year, but it meansthat only the most motivated surgeonsare able to join our team. This alsoexplains the close bonds that have beenestablished with various hospitals. Fiveor six members of the ARGOSassociation are surgeons who havecompleted this biomechanics training.

You are also a member of ARGOS;in what way can the Association

April 2001 - N° 3 ARGOS SpineNews 9


ois Lavaste : PART

Numerical model of the spine - Collaboration LBM - Sofamor Danek



contribute to the exchangesbetween biomechanicalengineers and surgeons, andpossibly manufacturers?

It is always the same objective:topromote closer bonds betweenspecialists from various disciplines. It isa forum in which each member canbenefit from the other's experiencewithout any further reason. This isimportant, as, in the early days of LBM,people predicted that our project wouldfail since we would never be able tocollaborate with the medical profession,a closed and self-confident world. Wewere even warned that we wouldbecome servants to these “superior”masters. But the reality was verydifferent, as the relationships that weestablished through formation of theDEA training programme allowed us tounderstand and respect each other.

Has the LBM established jointprojects with industry andespecially with the automobileindustry?

Our collaborations with the automobileindustry represent a knowledge transferfrom orthopaedics to the automobileindustry. We made every effort todemonstrate the advantages ofmodelling the human body as we hadpreviously done for orthopaedics. It took6 months of discussion to convincethem, because they were not at all ready

to accept this type of approach. At thetime, they were essentially working withmechanical dummies, but we eventuallyconvinced them to undertake anoperation supported by the FrenchMinistry of Research. This was in 1990,and the process then started to developfairly rapidly. Car manufacturers werealready interested in biomechanicsusing dummies, and tests with cadaversplaced in vehicles. They simulated theshock and then examined the lesionscaused to the bodies. We provided arepresentation of the human body withour digital models and simulations.

Has this type of collaborationbetween the LBM and carmanufacturers also beendeveloped in other countries?

I think that France was one of theleading cou ntries in this field. We wereone of the first countries to possess a

complete model of the humanbody designed to simulate thebehaviour of the body inresponse to shocks. Thingsthen moved very rapidly; fiveyears later, in 1990, we alreadyhad the first elements of thevirtual human body. In 1998,our modelling was operationaland, at the same time, ourapproach was adopted byseveral other countries. Today,in 2000, most carmanufacturers are interested

in live models, but this wasn't the case atthe outset.

Why did you decide to developthis collaboration with theautomobile industry when youcould have confined yourinterests to the surgical field?

The director of biomechanical researchof two leading French car manufacturers(PSA, Renault) was a doctor. He had anidea very similar to our own concerningthe value of biomechanics both in thefield of orthopaedics and in the field ofprotection of the body in motor vehicles.This convergence of our two viewpointsand this easy relationship convinced usof the advantages of working together.We initiated a period of cooperationthrough a whole series of doctoratetheses.

Is it still just as difficult tocollaborate with the automobileindustry?

No, it has now become routine. We workwith car manufacturers in the context ofEuropean contracts. It has now becomestandard practice. Our work isconducted in collaboration with theINRETS (Institut National deRecherche sur les Transports et leurSécurité - National Transport SecurityResearch Institute). Our research andthat of the automobile industry areclosely related.

Optoelectronic motion capture of the lower limb on stairs (left) and analysis of the gait (right)

Mechanical and geometrical modelling of

the lower cervical spine

Experimental study of the behaviour

of an instrumented lumbar segment

with the VICON optoelectronic system

▲

▲

Do car manufacturers nowsystematically call onbiomechanical engineers whenstudying a new project?

Biomechanics has gradually become anintegral part of the design of a motorvehicle, but this is obviously not the onlyelement to be taken into account. This isan interesting development, as theengineers and scientists that we havetrained now work in the researchdepartments of leading car manufacturers,where they use models which weredesigned at the LBM in the frame of ourresearch. We have progressed from a fairlyabstract idea, considered to be somewhatbizarre, to a very concrete application: atechnological transfer in the field of cardesign.

Isn't this a form of «reward»?

I recently received a call from one of myformer doctorate students. I asked himwhat he was doing now, and he repliedthat he was in charge of setting up all ofthe infrastructure to allow application ofthe models designed at LBM for a leadingFrench car manufacturer. This means thatwe were not unrealistic when weproposed this research programme tenyears ago!

Do other areas of industry makeuse of the services provided bybiomechanics?

There is another field of application withwhich I am much less familiar. It concernsmilitary applications, both in the field ofaeronautics and the army. They have verydifferent objectives, as they want todetermine the behaviours of the humanbody either to protect it or to destroy it.We have not had any experience in thisfield. It is a branch of biomechanics whichpublishes fewer papers and which is lesspresent in the scientific community, but itis nevertheless a reality!



PURPOSE :The purpose of this training is to provide the main principles of mechanicsin order to apply them in the study of the biomechanical behaviour ofbony structures, ligaments, muscles (spine, coxo-femoral joint, knee…)- in order to better analyze the mechanical functions of the skeleton,either healthy or pathological

- in order to optimize the design and manufacturing of mechanical devicesallowing to restore or assist the damaged functions (prostheses,ostheosynthesis materials …)

The training addresses to:- Orthopædics surgeons (fellows, MD, hospital staff, department heads); - Medical doctors in functional rehabilitation;- Biomedical engineers and technicians

PROGRAM :■ Joint Kinematics and dynamics

• theoretical principles • experimental tools:

- Fastrak electromagnetic 3D measuring device- Zebris ultrasound 3D measuring device- Vicon opto-electronic 3D measuring device

■ Eperimental analysis of the biomechanical behaviour of the spine, the knee … ■ The use of the Finite Elements Modelling technique in Biomechanics ■ Geometrical and mechanical modelling of the spine and of the human skeleton

joints ■ Modelling and experimental analysis of the behavior of spinal implants and

joint prostheses ■ Workshops on geometrical and mechanical modelling using the Finite

Elements Method

LANGUAGE: French only

REGISTRATION FEE: 7 000 FF.

LOCATION : ENSAM de Paris - 151 bd de l'Hôpital – 75013 PARIS

CONTACT: Michel POMPIDOU – Training Programmes Manager

PHONE: +33(0)1.44.24.64.90

BOOKING: FAX: +33 (0)1.44.24.64.74

REGISTRATION LIMIT: 10 people.

Initiation to BIOMECHANICSfor Implant Design and Manufacturing

(Experimental analysis and modelling)

4 days training : 7, 8, 11, 12 juin 2001

Do you have any contacts withthis branch of biomechanics?

I know that it exists ... I have certainideas about their research, but I do nothave any direct contact with them. Ithink that they have their ownspecialized teams, and that they conducta very particular type of research. Is itpossible to develop a projectile that cantravel throughout the body and destroyit? Is it possible to determine how theprojectile reacts when it meets aresistant material such as bone? Can thissame projectile be deviated to that it hasa larger trajectory, etc. ? These are thetypes of problems that military scientiststry to solve. It nevertheless remains abiomechanical approach. They have alsodesigned models to investigate thesequestions. There have been attempts tocollaborate in the context of the "Fenit"programme, which was set up by theFrench Ministry of Transport andIndustry to improve problems ofsecurity, ergonomy and comfort relatedto road transport. We held a jointmeeting with military scientists at whichthey have presented their researchprogrammes. We have also evaluatedthe mechanical characteristics of thearmy's fixation device (a bone fracture

stabilization system) but, in thisparticular case, the applicationconcerned orthopaedics.

Back on the subject oforthopaedics, what are the maincontributions of the LBM tospinal surgery?

I don't know whether we can claim tohave contributed to the progress ofspinal surgery, but I think we haveprovided certain objective elements tothe assessment of biologic phenomena.We have developed simulations usingdigital models tested on anatomicspecimens in order to obtainquantitative information. Once again, Idon't think we can claim to have madean extraordinary contribution, but Ithink that we have facilitated a betterunderstanding of biomechanicalphenomena within the spine: itsbehaviour, function, reaction to implants(and everything concerning boneremodelling around implants),stabilization of the human body, and thecorrection of scoliosis. We haveprovided greater objectivity to thesurgeon's subjective assessment. We arenow working with clinicians in thesurgical planning phases. They preparethe procedure on the basis of data of the

clinical examination andradiographs, i.e. qualitativeelements. The surgeon examineshis patient and then uses hissurgical experience. As anexample, we can provide him,with a quantitative analysis of therigidity of scoliotic curvatures bysimulating the behaviour of thespine, which enables the surgeonto integrate additional informationinto planning of the surgicalprocedure. When we reconstructthe spine in three dimensions andobtain spatial geometric data, wetry to understand how optimally torestore the vertebral column andreduce scoliotic curvatures.

What are LBM's main projects?

Essentially,we have two main types ofprojects. At the level of basic research,we are developing increasingly precisemodels, towards a virtual human body.Another actively growing field is ourdesire to assist in preoperativeassessment, intraoperative practice, andpostoperative evaluation. We are nottrying to hold the surgeon's hand, butrather to provide him with informationduring the surgical procedure.Providing the surgeon with real-timeinformation about the state of thecurvature on which he is operating andon the degree of correction of thiscurvature constitutes a good example ofobjective assessment. Globally, a visualdisplay will allow the surgeon to see thestate of progress of the spine duringtreatment and, in parallel, it will alsoprovide him with quantitativeinformation about the curvature to beincreased. This information will allowthe surgeon to optimize the procedurewithout replacing the surgeon by arobot. Qualitative and quantitative dataare combined to ensure an increasinglyeffective procedure. ■

Interview by C.S. Parent



Study of the mechanical

behaviour of a femur in

monopodal position

3D FEA modelling of the human

knee (LBM-ENSAM, Compared

Anatomy Laboratory - Natural

History Museum, Paris, URA

CNRS 1137)

3D FEA modelling of a knee

prosthesis (LBM-ENSAM,

CEDIOR)

communicationReaders Forum


Readers ForumReaders Forum

To the editorial staff of ARGOS Spine News,

Please allow me to congratulate you on thisbeautiful new publication, ARGOS Spine News. Iwish to comment on your interview with PrFrançois Lavaste. You posed the question: Whatis biomechanics? I would offer the observationthat Orthopaedic Surgery is a combination medicalsciences surgical art and mechanical principle whichwhen is applied in human, and thus is Biomechanics.

In light of this, we should not forget the work ofNicolas Andry, a leader of eighteeneth centurymedicine who wrote his thesis in Orthopaedics in 1744.(editor’s note:how could he write his thesis in 1744, if he died in 1742?) He hadobserved gardeners supporting falling trees and applied thismechanical principle to the design of a brace for correcting kyphosisin children. This principle, as demonstrated in my letterhead, becamethe accepted symbol of orthopaedics.

Nicolas Andry studied medicine at Rome and Paris and received thedegree in medicine in 1697 at age 39. Four years later he wasappointed as professor in the college de France and a member of theeditorial board of the Journal des (editor’s note: what is this?) In1724, he assumed the post of Dean of Faculty of Medicine.

Andry actually coined the word “Orthopedie”. To quote: “As to thetitle, I have formed it of two Greek Words, viz, Orthos, which signifiesstraight (sic) or free from deformity, and pais, a child. Out of thosetwo words I have created L’Orthopedie to describe my differentmethod of preventing and correcting deformities in children.” Hisbook contains fundamental information on curvature of spine,clubfeet, and congenital dislocation of the hip. Andry died in 1742,one year after the publication of L’Orthopedie.

A brief glance at L’Orthopedie will remind us of the debt we asorthopaedic surgeons owe this great man. It is now time that werecognize him as the founder of biomechanics, too.

ASN: What led you to the field ofcomputer-assisted surgery?

JT: I trained in computer science andjoined the TIMC laboratory after adoctorate thesis in Grenoble incomputer science or, more precisely,robotics in a laboratory with no activityin the biomedical field. In 1990, Idecided to spend a year at TIMC tobroaden my range of skills in robotics. Iwas immediately attracted by theclinical application of this field and, assuch, I did not leave the laboratory atthe end of the year. I was a researchscientist from 1990 to 1996, when I wasappointed director of the CAMSPgroup.

ASN: When and why was theTIMC laboratory founded?

The TIMC laboratory was founded inthe early1980s within Joseph FourierUniversity, then called Universitéscientifique, technologique et médicale(scientific, technological and medicaluniversity) (Faculties of medicine andscience). The Dean, Professor Sarrazin,wanted to create a research departmentcomposed of scientists, clinicians andbiologists and to pursuemedicalprogress by novel scientificapproaches. In 1982, JacquesDemongeot, medical doctor andmathematician, created this department,which was initially called "theDepartment of Biostatistics". It wasrenamed TIMC (Techniques del'Imagerie, de la Modélisation, et de laCognition - Imaging, Modelling, andCognition Techniques) but maintains

the same multidisciplinary approach ofclose research collaboration, withoutplacing the engineer at the service of theclinicians, or vice versa.

ASN: What are the main activitiesof the TIMC?

The common denominator of all of ourresearch activities is the application ofmathematics and computer science tomedicine and biology. The TIMC is nowcomposed of 8 teams, ranging from basicscience to more applied research(modelling, image processing, artificialintelligence, microtransducers, genomicdatabases, physiology of breathing,CAMSP)and we have a very broad rangeof research topics.

ASN: Who are your main clinicalpartners?

Proximity facilitates our collaborationwith about twenty departments ofGrenoble teaching hospital, ProfessorPhilippe MERLOZ, (in spinal surgery),Professor SARAGAGLIA (SouthHospital, Department of Orthopaedics),and Professor Remi JULLIARD(Clinique Mutualiste of Grenoble), are afew of our closest colleagues. As you cansee, our clinical partnerships areessentially local.

ASN: Do the engineers workingin the TIMC regularly visitsurgical departments?

It all depends on the type of researchwork. Relatively basic research, such as

the design of a new robot, does notrequire regular presence in the clinicalsetting, at least in the early phases. Incontrast, other projects require part-time or full-time presence of cliniciansin the laboratory in order to define theneeds and the environmentalconstraints, and the presence ofengineers in the operating room forvalidation and clinical trials.

ASN:How is the laboratorycomposed?

The TIMC is composed of about 130people: one-half are permanent, andhalf are post-doctorate fellows ordoctorate students. The CAMSP team iscomposed of about 30 people andreceives about fifteen students per year(DEA, engineering students, DESS orMaster's students).

ASN: You introduced the conceptof CAMSP, which is broader thanthat of computer-assistedsurgery. What are your activitiesbeyond the medical and surgicalprocedure per se?


trainingTIMC Laboratory

Mrs. Jocelyne TroccazThe director of the CAMSP group (computer-assisted medical and surgical

procedures) in the TIMC laboratory (Techniques de l'Imagerie, de laModélisation, et de la Cognition), kindly allowed us to visit her laboratory,

near Grenoble teaching hospital. She gave us a guided tour of one of theleading centers in computer-assisted surgery research.

trainingTIMC Laboratory


We have worked or are currentlyworking in a number of non-surgicalareas, such as medical imaging (imagerepositioning, data superimposition), incollaboration with radiologists; we arealso currently working with radiologiststo develop 3D reconstructions fromintraoperative radiographs obtained bydigital transducers. Radiotherapy isanother research field (both for planningand conduct of treatment). We are alsoworking in the field of respiratorymedicine in the form of computer-assisted bronchoscopy . These are just afew of our ongoing projects.

ASN: What are the maininternational CAMSP researchlaboratories?

It is hard to give a complete list. Thelargest laboratory was formed relativelyrecently at Johns Hopkins University(Baltimore, USA) by Professor RussellTAYLOR. Professor TAYLOR has adeep robotics background (he designedthe Robodoc system) and after working

with IBM for many years, he coagulateda research team around the theme ofCAMSP with the usual 3 axes (research,training, and industrial partnerships),with the financial support of the USgovernment.In the United States, the researchcenters in Boston, around MIT andHarvard University, and in Pittsburgh atUPMC Shadyside (See. ARGOS NEWSPINE No. 2) also play a leadingpredominant role. We often work withthe Helmöltz Institute team in Aachen,Germany; Paolo DARIO's team isparticularly interested inmicrotechnologies and robotics. InSwitzerland, Professor Lutz NOLTE atthe Müller Institute has specialized incomputer-assisted orthopaedics. Anumber of teams have been set up inEngland, for example the London teamdirected by Prof. Brian DAVIES andProf. David HAWKES. In France,centres such as INRIA, are morespecifically devoted to medical imagingand various image processingtechniques. The TIMC is, in terms ofthe number of projects developed andthe quality and close proximity of itsclinical partners, clearly one of the mainCAMSP laboratories in the world.

ASN: Who are the key peoplewho have nurtured theserelatively young disciplines overthe last ten years?

Without hesitation, Russell TAYLOR inthe United States, whose work on theRobodoc system is largely responsiblefor the media coverage of thesetechnologies.

In France, Philippe CINQUIN wasresponsible for the development ofsurgical navigation technologies in theGrenoble region in the eighties, but itmust be remembered that this workwould not have seen the light of daywithout the assistance of the clinicianswith whom we work. In spinal surgery,for example, a real long-termpartnership has been developed withProfessor MERLOZ.

ASN: What proportion of yourresearch activity is devoted toorthopaedic surgery?

I don't think it would be an exaggerationto say that almost 50% of our clinicalactivity concerns the field oforthopaedics. We have many projectsconcerning navigation in surgery of thespine, pelvis, and knee (totalarthroplasty, ligamentoplasty), andconcerning medical imaging. Half of ourclinical partnerships and the variousongoing European projects concernorthopaedic surgery.

ASN: How are cliniciansintegrated into your researchprojects?

This integration is primarily "structural",as the laboratory is partially composed ofmedical doctors. Secondly, severaldoctors and surgeons complete theirdoctorate-of-science theses at theTIMC, on a part-time basis,simultaneously with their everydayclinical practice. Once again, ourproximity to the Grenoble teaching

Peroperative 3D surface reconstruction of the lumbosacral spine using an ultrasound (echogaphy) system.

Percutaneaous screwing of the sacroiliac joint.

Semi-active serial robot. The robot is not

moving the pen, but the human hand is guided

by the robot on a pre-program track. Some

areas can be allowed, some others forbidden.


trainingTIM-C Laboratory

hospital is a major advantage in thiscontext. These clinicians generally workin teams with an engineer, who is alsopreparing a doctorate-of-science thesis.The contribution of doctors usuallyconcerns defining needs andconstraints, modalities ofexperimentation, and clinical validation.They are obviously a central componentof the industrial partnership.

ASN: In your opinion, what arethe major contributions ofCAMSP to spinal surgery at thepresent time?

At present, our work centers onnavigation techniques for pediclefixation , but these contributions arediversifying even as we speak.

ASN: For example?

Enhanced endoscopic surgery isprobably one of the main objectives ofCAMSP over the next decade. Thecombination of navigation andendoscopy technologies will soon allowthe development of new minimallyinvasive techniques for spinal surgery.With the progress in intraoperativeimaging, techniques will evolve andnew surgical approaches will bepossible. The integration of newtransducers into surgical

instrumentation could alsobe a factor in technicalimprovement.

ASN: Computer-assisted pediclefixation currentlyappears to hesitatebetween tomographicnavigation (CT scan)and fluoronavigation.Where is thistechnology going?

The choice of one or otherof these two modalities willundoubtedly depend on the clinicalsetting. The high radiation dosageincumbent in CT would prevent it frombeing used systematically, especially inadolescent scoliosis. MRI may representan alternative in this setting. Theefficacy of fluoronavigation has yet to bedemonstrated. Fluoronavigation is verypromising since it does not require asophisticated preoperative examinationand uses less radiation, but, for themoment, it can only provide mediumquality 2D images, which are markedlyinadequate in severe spinal deformities.In any case, these techniques willcertainly be improved over the next fewyears. We are also working ontechniques of intraoperativerepositioning of 3D CT reconstructionsof the spine by ultrasound, which willopen new perspectives in minimallyinvasive surgery.

ASN: In your opinion, what is thefuture of robotics in spinalsurgery?

Like all aspects of spinal surgery, this isa difficult question! The presence ofsensitive anatomic structures, such asnerve roots and the dura, makes the useof robots particularly hazardous,requiring extremely careful and detailedrisk assessment and, quite probably, thedesign of new robotic approaches.

Unlike the classical robotic approachesto orthopaedic surgery (Robodoc - ISS,Caspar - Orthomaquet), our roboticapproach is not independent (the robotautomatically performs part of theprocedure), but dependent (theprocedure is performed entirely by thesurgeon, but limited in space by therobot during the most delicate phases,as if a "third hand" guided the surgeon'shand to ensure that the procedurefollows the preoperative plan).Miniaturization of robotic components,especially operating devices andtransducers, will allow the clinicaldiffusion of these robots in the nearfuture.

ASN: As the new millenniumbegins, we are watching anInternet explosion. What is therole of the Internet in thedevelopment of CAMSP?

The Internet will undoubtedly have adominant influence on training andteleteaching. In my opinion, remote-controlled surgery (or telesurgery) viaInternet at sites geographically distantfrom each other, will be confined to thefield of isolated demonstration for manyyears to come.On the other hand, sharing of scientificdata and know-how between centersspecialized in a particular medical or

Image Guided Orthopaedic Surgery (Fluoronavigation)

Images guided pedicular screwing

surgical discipline is rapidly changingthe face of current teaching methods inmedicine and surgery, but we mustremember to pay particular attention tothe source and reliability of these data!

ASN: Do you have anyteleteaching project underway?

The VOEU project (Virtual OrthopaedicEuropean University) is an Europeanproject following two other projects:IGOS (Image Guided OrthopaedicSurgery) and IGOS 2. These twoprojects were designed to ensure thedevelopment and clinical validation ofCAMSP systems in orthopaedic surgery.The VOEU project is designed todevelop computer technologies in thearea of orthopaedic surgery teaching.Several trials of access to trainingthrough Internet have been organized,especially in the field of pharmacologyat the Grenoble Faculty of Medicine.These courses are interactive and notexclusively comprised of text. Forexample, various multimediaquestionnaires allow self-assessment ofcandidates. In the context of the VOEUproject, models of orthopaedic surgerytraining courses and simulation tools(clinical models or surgery simulators)are being developed, in the fields ofknee, hip, and pelvis surgery, and

shoulder arthroscopy.

ASN: What are your objectivesfor the next ten years?

In the field of orthopaedic surgery,particular emphasis will be placed onthe development of tools facilitatingminimally invasive surgical procedures.Endoscopy, repositioning techniqueswithout palpation, such as ultrasound, or3D interpretation of digital subtractionx-rays (ongoing European MI3 Project)are several examples. We can also expectprogress in image processing tools andthe development of new visualizationsystems which will facilitate the clinical

use of surgical navigation systems. Modelling of clinical data and anatomicinformation, especially concerning softtissues, is a rapidly growing field ofresearch at TIMC (mainly in cardiac andgastrointestinal surgery). Collaborationsbetween our discipline andbiomechanics will be one of the mainfactors leading to innovation over theyears to come. The spine, for example,has been the subject of manybiomechanical studies performed bylaboratories such as LBM-ENSAM,directed by Professor FrançoisLAVASTE and Wafa SKALLI (SeeARGOS SPINENEWS No. 2),especially concerning geometric andmechanical modelling of the healthy,injured and reconstructed spine, butalso associated implants and surgicaltechniques. These laboratories are alsoincreasingly developing their researchin the fields of medical imaging, which isalso one of our areas of interest.Biomechanics and computer-assistedsurgery are complementary dsciplines,which must collaborate more in the nearfuture to enhance the development of aglobal therapeutic continuum, frompersonalized modelling to the surgicalprocedure and beyond to long-termfollow-up of the clinical results.

ASN: PRAXIM company, thesubject of another interview inthis issue, is one of your mostimportant partners. Can you tellus more about this partnership?PRAXIM previously ensured the linkbetween research and industrialization(in the context of our partnerships withmajor companies such as Medtronic,Sofamor, Danek, or Aesculap). Thisengineering activity has gradually beenreplaced by an autonomous activity anddirect industrialization. The industrialapplication of TIMC's research isessentially ensured by PRAXIM, whichnow produces its own navigation station(Surgetics). ■

Interview by A. Templier


trainingTIM-C Laboratory

Information Flow diagram in Computer Aided Surgery Systems development

3D surface matching by deformation of a 3D

statistical model

ASN: Can you explain to us whatled you to the field of computer-assisted surgery?

SL: During my training as an engineerat Sup'Télécom in Brest, I becameinterested in the biomedical field and Iworked for companies in this field whileI was a student. I started a thesis inGrenoble in the TIMC laboratory in1986, with Philippe CINQUIN, whowas in the process of creating hisCAMSP team (computer-assistedmedical and surgical procedures). Mythesis subject concerned computer-assisted percutaneous nucleolysis basedon CT images, and it seems to me thatthis problem has still not been entirelysolved.

ASN: When and why was thePRAXIM company created?

PRAXIM was founded in 1995 when agroup of scientists, including myself,initially directed by Philippe CINQUINand later by Jocelyne TROCCAZ,decided to develop a structure thatwould facilitate the laboratory researchby association with leading medicalcompanies such as B-Braun (Aesculap),Medtronic, Sofamor, Danek, or Stryker.

ASN: What are your fields ofinterest apart from orthopaedicsurgery?

We are currently bringing products tomarket in three fields. The first isorthopaedic surgery in general, thesecond is ENT (See Figure), intranasal

and cranial surgery, and the third isdental and maxillofacial surgery, with aspecialization concerning computer-assisted dental implantology.

ASN: What percentage of yourwork is devoted to orthopaedicsurgery?

Orthopaedic surgery has a predominantplace in PRAXIM, in line with currentmarket trends. We believe thatwe havean authentic explosion in computer-assisted surgery in orthopaedics at thepresent time, and we are participating inthis explosion, in both development andmarketing. The first PRAXIMdevelopments were applications in knee(See figure) surgery and spinal surgery.

ASN: Can you briefly describethe international computer-assisted orthopaedic surgerymarket?

There are approximately 1,500computer-assisted surgery systemsthroughout the world at the presenttime, but only several hundred are

devoted to orthopaedics andtraumatology. This is a very rapidlyemerging market as a result of severalfactors. The first one concerns thegrowing demand expressed by patientsand identification of the real potentialapplications of these technologies tosolve various problems in orthopaedics.The locomotor apparatus is particularlysuitable to computer-assisted surgery,which essentially concerns integrationof 3D geometry, modelling, andregistration. The second factor concernsthe orthopaedic implant manufacturers,who consider these systems aninnovative and often clever way ofpresenting and promoting their know-how, and of providing their customerswith a real added value.The third factor concerns the demandby orthopaedic surgeons, who viewthese systems as a natural step in theevolution of technological and scientificprogress that makes their surgicalpractice more reliable, increasinglyeffective, and less invasive.As a result of all of these factors, severalhundreds of these systems should be inuse in every industrialized country inthe near future.


communicationPRAXIM

Interview with

Mr Stéphane LavalléeChief Executive Officer of PRAXIM (Perception, Raisonnement, Action enMédecine - Perception, Reasoning, Action in Medicine), is one of the worl-d's leaders in computer-assisted surgery. He presents his approach to this

rapidly growing market and these new technologies.

Surgetics screen of the ENT navigation

software

Total Knee replacement planning

(Femoral implant).

communicationPRAXIM


ASN: You are marketing anopen navigation station(SURGETICS) (See figures).What are the main advantages ofthis open device?

Two computer-assisted orthopaedicsurgery systems are available at thepresent time: the so-called "closed"systems, reserved for a specific implantmanufacturer, and the "open" systems,such as our Surgetics device. Opendevices satisfy the surgeon's demand tobe able to work on multiple applicationswith implants from variousmanufacturers, who are oftencompetitors. The interest of an opensystem is to allow the surgeon toperform knee arthroplasty withmanufacturer X, spinal surgery withmanufacturer Y, anterior cruciateligament reconstruction withmanufacturer Z, and perform hip orshoulder arthroplasty with anothermanufacturer, etc.

ASN: What applications will beavailable on SURGETICS withinthe next two years?

We are going to start with the mainapplications in orthopaedic surgery,which obviously include the spine, witha number of different variants.This alsoincludes knee arthroplasty, either totalor unicompartimental; kneeligamentoplasty; lower limbosteotomies, total hip arthroplasty andtraumatology, and especially femoralpinning. Applications such as theshoulder or ankle arthroplasty will bedeveloped subsequently.

ASN: You are a partner ofSURGIVIEW, specialized in thedevelopment of computer-assisted diagnosis and clinicalfollow-up systems in orthopaedicsurgery. What is the purpose ofthis partnership?

Navigation, which is at the core of theoperating room, is able to take varioustypes of data into account, and providevery precise quantitative data derivedfrom a computerized surgical protocollike those developed by Surgiview. If westopped at this point, we would lose animportant potential benefit of thesesystems, which integrate these data intothe management of the operating roomand in the surgeon's everyday practice,thus providing patients with an ever-increasing quality of care. Ourpartnership with SURGIVIEW is anessential and strategic partnership.

ASN: Computer-assisted pediclefixation appears to hesitatebetween classical navigation (CTscan) and fluoronavigation. Whatis your position?

The use of preoperative 3D imagingremains essential in cases with severespinal deformities. In other morecommon and less complicated cases,fluoronavigation can be sufficient. Inaddition to these two techniques, bothpart of our portfolio, we propose anintermediate solution, based onintraoperative image acquisition usingfluoroscopy, with 3D geometricreconstruction using an "atlas" type ofstatistical model (See Figure). Thisapproach is designed to combine thesimplicity of fluoroscopy with the threedimensional reconstruction availablewith computerized.

ASN: In your opinion, what arethe major innovations likely to bedeveloped over the next fiveyears in spinal surgery?

I think two main innovative aspects willbe combined. The first aspect, aboutwhich everyone is talking, is minimallyinvasive surgery, which is difficult toimplement with currently availabletechnologies. It will become easier andeven simple with the futureSURGETICS technology. The secondaspect is global visualization of the spineduring surgery, combined withpreoperative planning designed toensure an optimal procedure accordingto the patient's preoperativemorphological and functionalconfiguration.

ASN: In your opinion, what arethe main obstacles to thedevelopment of robotics inorthopaedic surgery?

I believe that, up to now, we have alwaysput "the cart before the horse". I comefrom a robotics background, in which Ideveloped an active system devoted tostereotactic neurosurgery. I havesubsequently changed my mind, as theso-called "passive" navigation systemsoffer a number of functional options - an

SURGETICS Station

added value whose limits cannot evenbe suspected at the present time - andsolve multiple problems. Robotics,initially used as a response to theseproblems, now appears to be an error;an error which is even harder to justifyin view of the high cost of these systems,which are technically difficult todevelop. I think that, in the long term,robotics will be an "instrumentalancillary", in which navigation will

constitute the first level ofancillary, although some of itsphases could possibly berobotized, to ensure greaterprecision and increasedsecurity. Moreover, robots arenot purely "active", such asRobodoc and Caspar robots,but can also be semi-active, inthis case, the robot, often muchmore compact, simply guidesthe surgeon's movements, andprotects certain high-riskzones.

ASN: A knee surgeondoes not have the sameconcerns as a spinalsurgeon. You aredeveloping applicationsfor orthodontists, ENTsurgeons, etc. How doyou deal with thesemultidisciplinary

requirements?

We are in contact with a wide range ofsurgical specialties and we adopt apragmatic approach to this diversity. Westrive to find solutions to very concreteand very specific problems in co-operation with clinicians. Ourpartnerships with surgeons at theforefront of their field, and withmanufacturers of implants, allow us toacquire all of the knowledge necessaryto develop our systems. An all-purpose

SURGETICS machineobviously does not exist.We have developed asoftware and equipmentplatform responding to allof the generic needs ofsurgery, but the

development of each application isessential and differs each time, just asthe problems to be addressed also differ.

ASN: Who are your scientific andclinical partners?

Our main scientific partner is the TIMClaboratory, situated a few metres fromour premises, with its CAMSPdepartment directed by JocelyneTROCCAZ. We have exclusive rights toabout ten of this laboratory's patents, inour fields of activity.We have an increasing number ofclinical partners. For the moment, theyessentially operate in the Grenobleregion and mainly consist, in the field oforthopaedics, of Professor MERLOZ'steam at Grenoble teaching hospital forthe spine, and Professor JULIARD'steam at the Clinique Mutualiste inGrenoble.

ASN: What are PRAXIM'sobjectives for the next five years?

Our objectives are to meet the growingmarket demand by positioning ourselvesas one of the leaders in orthopaedic,ENT, and maxillofacial surgery. We thenhope to establish our presence in othermarkets as a result of technologicalderivation.

ASN: And your objectives for thisyear?

Our short-term objectives are to launchour first products. 2001 is the year ofSURGETICS, particularly in the fieldsof intranasal, dental and orthopaedicsurgery. Several applications for theknee, in collaboration with variousindustrial partners, will immediatelyprovide users with an open solution. Wewill also launch a first product for spinalsurgery this year. ■



communicationPRAXIM

Stephane Lavallée and the SURGETICS Station

3D Matching of a statistical

model to the real anatomical

surface

(example of the Tibia)

THANK YOU FOR YOUR CONTRIBUTION !

WE WILL SEE YOU NEXT YEAR…

Photos taken from the5TH International

Argos symposium

communicationFifth International Argos Symposium


SESSION One, "A Virtual Trip onthe Spine Planet," was devoted to

imagery. Mr. Leonard Fass (GeneralElectric) provided an overview ofinnovations and future prospects inspinal imaging, emphasizing that MRI,CT scans, and standard X-rays are usedin a complementary way. MRI and CTscan present certain advantages, such ashigh contrast, direct axial imaging,surgical operation control, multi-slicereconstruction, and virtual endoscopy ofthe spine. While CT scan offers imagesof the bone and calcium, MRI is suitedto visualize bone marrow and spinalnerves. For the time being, ligamentsand scar cannot be visualized with thesetwo techniques. For nerve imaging, it isstill necessary to use intravenouscontrast agents, which make thesetechniques semi-invasive. Volume

rendering shows arteries and bloodvessels in relation to the spine. Mr. Fassmentioned that improvements must bemade to eliminate artifacts in ultra-high(100 micron) resolution. In the future,the trend will be from closed MRIsystems, which offer better imagequality, to open systems, which are moredynamic. Professor Jacques De Guise of theImaging & Orthopedics ResearchLaboratory in Montreal spoke on "3DImagery: Realism vs. Accuracy." Hereviewed various imagery techniquesfor orthopedic surgery, outlining theiradvantages, disadvantages, and potentialdifficulties. Traditional CT scanproduces multi-slice images, but newtechnology has led to spiral images andvoxels (3D data sets). The speakerdiscussed the four possibilities using CT.The first is the classical axial acquisition(re-slicing), which provides 2D images;it presents the advantage of being quickand simple to use. One disadvantage isthat it requires data interpolation.Second is MIP (maximum intensityprojection). This technique is mostappropriate for vascular pathologies; it isalso quick, simple, and gives 2D images.Artifact is the main problem with thistechnique. The third method describedby Professor De Guise is surface

rendering, which offers 2D-3D contourdetection, polygonal models, andcomputer graphics. Surface renderingprovides visualization in real time and issimple and quick. However, it requiresan enormous amount of data andreproduces only the surface of objects.The source of incongruities may be hardto determine. Although the images itproduces are quite impressive, thistechnique requires the presence of anexpert, is long and fastidious, andinvolves a complex method ofautomatization. Volume rendering, thefourth possibility, involves projectingthe 3D data set onto the imaging planeand offers the advantage of being avirtual X-ray, allowing anatomic cuts forteaching anatomy. However, it requiresa huge amount of data; it is operator-dependent; it produces artifacts; and it iscomputer-intensive. There is no direct

Fifth International

Argos Symposium:

A Spine OdysseyJanuary 26th, 2001 - Maison des Arts & Métiers - ParisAs the crowning event in a week dedicated to the spine, the Fifth Argos Symposium focused on theuse of technological innovations in spinal surgery. Dr. Christian Mazel opened the day's events andwelcomed Argos members and other participants.

Mr Leonard FASS (General Electric) Pr. Jacques De Guise, PhD

access to 3D geometry. The speakerexplained that biplanar radiographycould replace CT scans. It is veryprecise and uses low-dose radiography.This technique, however, is only asurface rendering technique andrequires the assistance of an expert aswell as a priori information. In conclusion, Professor De Guisestressed that these are virtual images,which may very well differ from reality.One may rightly ask, "What is real andwhat is virtual?" There have beenrelatively few studies on the precision ofthese techniques and their clinicalrelevance (M.W. Vannier et al, Iowa).The speaker concluded that there aremany 3D methods and no perfecttechnique; the choice depends on thecontext. For optimum precision, oneneeds a large data set, time, and theassistance of an expert. After a wealth of information from anengineering perspective, the nextpresentations were given by clinicians.Professor Jean-Claude Dosch outlinedthe latest innovations and contributionsto diagnosis and new therapeuticperspectives. In the field of digitalradiography, he reviewed conventionalX-ray techniques: CT, MRI, PET(Positron Emission Tomography). Prof.Dosch discussed clinical applications of

the above-mentioned techniques. Theyare used for spinal trauma using 3D and2D images. Multitissue imaging has fewapplications currently. He stressed thatthe clinical application of 3D imagesessentially concerns the detection ofintervertebral dislocation and unilateralluxation. He then reviewed clinicalexamples using MRI imaging indegenerative pathologies: myelo-MRI,dynamic MRI, and in post-operativediagnosis of infections. In hisconclusion, Prof. Dosch emphasizedhow valuable imaging techniques are fordiagnosis and therapeutics; one may askwhether France is lagging behind in theacquisition of the necessary equipment.These techniques are not 100% reliableand surgeons should not forgetconventional techniques (X-rays). In thefuture, and to reduce artifacts,techniques can be combined. The panelemphasized the complementary natureof the various techniques. Clearly, onecannot sacrifice precision for the sake ofimage quality, regardless of howbeautiful the pictures may be. Session Two focused on "The State of theArt in Robotics and Spine Surgery." Thefirst speaker, Dr. François Laborde, is acardiac surgeon who heads anexperimental surgery laboratory inwhich robots are used. The goal of

robotics in surgery is to improve thesurgeon's autonomy and offeradvantages for patients; the speakerexpressed the need for more progresstoward reaching these goals. Dr. Laborde reviewed the three types ofrobotic systems currently available(Intuitive, Zeus, Caspar). Theadvantages of mini-invasive surgeryusing robotics for the patient include:smaller incision, less pain, shorterhospital stay, faster recovery, greaterpatient comfort, etc. For the surgeon,advantages are primarily improvedergonomics, greater control, savings incosts and time, etc. The main advantagein using robots is automatic response,image-guided positioning, and thetarget-tracking system, in addition to thehigh level of precision. Using robotsrequires past experience with videosurgery plus dry and wet lab training.Dr. Laborde warned that the learningcurve must definitely be taken intoaccount when a surgeon is consideringthe use of robotics. The speaker alsoaddressed the ethical/philosophicalconsiderations related to this kind ofsurgery. In the next speech, "Is There a Robot inthe Operating Room?" Dr. AdrianLobontiu presented an intuitive robotmade by Intuitive Surgical (Mountain



Pr. Jacques De Guise, Phd

Mr Leonard FASS,

Pr. Christopher Ullrich, MD

Pr. Jean-Claude Dosch, MD

JanuarMaison des A

Argos’ symposium> January 31st, 2002

13h30 to 17h30

and February 1st, 200208h30 to 12h00

Free communications> February 1st, 2002

14h00 to 16h00

The lumbar and lumbo-sacraldegenerative spine

6TH

ArgosAs every year, the 6th ARGOS Meeting willtake place at the “Salons des Arts & Métiers”in Paris. This beautiful private parisian man-sion seems to adapt perfectly to the meeting spi-rit. Indeed, it favours conviviality, exchange ofviews and dialogue. The symposium will lastfrom Thursday afternoon to Friday Morning.Friday afternoon will be devoted to free com-munications.

To give the good indication of a lumbar orlumbo-sacral fusion is the guarantee of a

good functionnal and clinical result. This is thekey point of the treatment. Several schools,even philosophies are opposite in this field.However, it is certainly possible to access to arather common attitude. That’s why we wishto have the opinion of few of you to help us todefine easily what can be considered as the“good indication”.

The second point that highly contributs to thequality of the result is the surgery’s strategy.Which levels are to be fixed? What kind offusion to do? These are important factors,which will influence the results. The topic iswide, source of many questions and examina-tions. This year, we only wish to discuss theindications and the surgery’s strategy in thetreatment of lumbar stenosis associated to anadult scoliosis or/and or to an arthritic spondy-lolisthesis, as well as in isthmic lysis and gradeone spondylolisthesis. The years 2003 and 2004will allow us to study the other indications offusion as regards of the common or post-discec-tomy low back pain, the disc herniation themulti operated spine and high grade spondylo-listhesis. We hope to have the pleasure to meetyou during these next meetings. ■

Lumbar awhich ind

In lumbar in isthmic

Dr Philippe BEDATDr Jean-Paul FORTHOMMEDr Frank GOSSETDr Alain GRAFTIAUXPr Pierre KEHRDr Christian MAZELPr Jean-Paul STEIBDr/Ing Alexandre TEMPLIERDr Richard TERRACHER

Scientificcommittee :

www.argos-europe.com

y 31 and February 1st 2002Arts et Métiers - 9bis avenue d’Iéna PARIS XVI FRANCE

Internationals symposium

and lumbo-sacral fusions :dications, which strategies ?stenosis associated to spinal deformities,c lysis and grade one spondylolisthesis.



View, California). He showed two shortfilms to demonstrate the range ofsurgical possibilities using the da Vincirobotics system in cardiovascularsurgery (coronary bypass) andlaparoscopic surgery (hernia repair,nissen procedure, adrenalectomy, etc.). After the presentation, Dr. ChristianMazel showed a film of himselfperforming open surgery on the duramater of a lamb with a robot. Althoughhe said the experience was interesting,this approach requires substantialtraining before it may be useful for thesurgeon; otherwise robotics is toocomplex to use and highly time-consuming, and therefore ofquestionable benefit for the patient.

Session Three, "Navigation in thePedicle," focused on surgery usingcomputer navigation systems. The firstspeaker, Mr. Harry Freitag, presentedthe "AESCULAP SPOCS" 3Dnavigation system. This SurgicalPlanning and Orientation ComputerSystem, developed in Germany hasapplications in neuro and spine surgeryand ENT. It has dedicated functions forvirtual screw position planning andsurgical guidance for screw implantationand provides real-time tracking ofinstruments. Prof. Pierre Kehr, the next speaker,described his experience with theSPOCS system. He was initiallyenthusiastic but found it very time-consuming in practice. He showed avideo of his team using the deviceduring a real operation, which hecommented upon for the audience.

First, patient CT data are transferred tothe SPOC device, one vertebra at a time.Next, the surgeon must place sixlandmarks per vertebra (superior andinferior articular apophyses and two forthe spinal processes). The surgeon thenplaces the virtual pedicular screws,calculating the entry/exit points, target,angle, etc. The synchronization phaseconsists of matching reality to the virtualdata that were fed into the system. Dr.Kehr reported that he had to start eachstep over more than once to ensureproper virtual placement of the screwsbefore actual surgery. Once thepreparatory phase was complete, thedevice enabled easy navigation. The speaker stressed the learning curve,once again. In addition, the system is notintuitive and requires mastery of thesoftware.Professor Philippe Merloz spoke aboutfluoronavigation. The C-arm is acommonly-used tool, but alone it doesnot provide axial images and is oftenresponsible for errors in spine surgery.Fluoronavigation uses the C-arm andimage-guided instruments, andcalibration target with embeddedLEDs, as well as a computer. Prof.Merloz described pedicular screwplacement using a fluoroscope,consisting of C-arm set-up referenceframe fixation; camera alignment; andinstrument calibration. The speaker outlined the advantages offluoronavigation, which is a moreintuitive method: it does not requirepre-operative CT, and there is no needto make a model or establish landmarks.However, it requires manual dataacquisition. Discussion of CT-based navigation and

fluoronavigation emphasized that forgreater efficiency, technicians should bein charge of support and preparatorysteps and pre-operative scanning shouldbe standardized. The panel once againstressed that the two techniques arecomplementary and not antagonistic. Inthe future, the combination of CT andultrasound will probably revolutionizethe field of imaging. The afternoon session was devoted toInternet and the medical practice. Itopened with Dr. Franck Schwabpresentation, "The Internet Experienceof a Surgeon" which he summed upvividly: "Developing a website is likefishing: it may sound easy, but it can bea real challenge." Internet isincreasingly affecting all the realms ofour daily lives, health care included.Today, 44% of Americans use internetand 36% refer to it for medicalinformation. For a surgeon, what are thebenefits of creating a website? Whatkind of resources are needed? What arethe options? What can we offer topatients? Such were the questions

addressed by Dr. Schwab(www.orthospine.com). The benefits arenumerous, since a website enablesindividual physicians or groups ofphysicians to provide specializedinformation to the patients who wouldotherwise consult other sources ofinformation — industrial or commercial.The site can also provide practicalinformation on hospital location, hours,answer FAQs (frequently askedquestions), offer extended patientcontact, etc.Dr. Alexandre Templier then

Pr. Gérard Saillant, MD & Dr. Christian Mazel, MD

Pr. Pierre Kehr, MD

Dr. Franck Schwab, MD & Pr. Gérard Saillant, MD

A g e n d aA g e n d a

4th Israeli Symposium on ComputerAided Surgery, Medical Robotics andmedical ImagingMay 17, 2001, Tel-Aviv, IsraelPhone: +972-4-829-3264Fax: +972-4-832-4533 E-mail: [email protected] http://www.cs.huji.ac.il/~josko/isracas2001.html/

3rd International Conference on 3DDigital Imaging and ModelingMay 28 – June 1st, 2001, Québec,CanadaPhone: (613) 993-0414Fax: (613) 993-7250 E-mail: [email protected]://www.vit.iit.nrc.ca/3DIM2001/

4th International Pediatric RadiologyMay 28 – June 1st , 2001, Paris ,Francee-mail: [email protected] & [email protected]://www.ipr2001.org/

International Conference on Augmented,Virtual Environments and 3D ImagingMay 30 – June 1st , 2001, Mykonos,GrècePhone : +30.31.464160Fax : +30.31.464164E-mail : [email protected]://www.iti.gr/icav3d/

The Fourth Combined Meeting of theOrthopaedic Research Societies of theUSA, Canada, Europe and JapanJune 1 – 3, 2001, Rhodos, GreecePhone : (847)698-1625 Fax : (847)823-4921http://www.ors.org/

Medical Imaging and AugmentedRealityJune 10 – 12 2001, Hong KongPhone : (852) 2609-8433Fax : (852) 2603-5024 Email : [email protected]://www.cse.cuhk.edu.hk/~miar2001/

IX Mediterranean Conference onMedical and Biological Engineering andComputingJuly12-15 , 2001, Pula, CroatiaPhone: +385 1 61 29 938Fax: +385 1 61 29 652E-mail: [email protected]://www.crombes.hr/MEDICON2001/

International Society for the Study ofthe Lumbar Spine June 19-23, 2001, Edinburgh, Scotlandhttp://www.issls.org/

Computer Assisted Radiology andSurgeryJune 27 – 30, 2001, Berlin, GermanyPhone.: +49 -30- 314 73100 bFax: +49 -30- 314 23596Email: [email protected]://www.cars-int.de/

XVIIIth Congress of the InternationalSociety of Biomechanics

July 8-13, 2001, Zurich, SwitzerlandPhone: ++41 1 633 61 17Fax: ++41 1 633 11 24E-mail : [email protected]://www.isb2001.ethz.ch/

25th Annual Meeting of the AmericanSociety of BiomechanicsAugust 8 – 11, 2001, San Diego,California, USAPhone : (858) 534-3940Fax : (858) 534-7672E-mail: [email protected]://www.asb-biomech.org/

3rd Annual Meeting of the SpineSociety of Europe September 4 - 8, 2001, Gotenburg,SwedenPhone: +46-31-342 34 05Fax: +46-31-82 35 84E-mail: [email protected]://www.eurospine.org/Meetings/es.01.html

The 57th Annual Congress of theH.A.O.S.T (Hellenic Association ofOrthopaedic Surgery and Traumatology)Sept. 12 -16, 2001, Athens, GreecePhone: +30 1 685 4156Fax: +30 1 685 4187

36th Annual Meeting of the ScoliosisResearch SocietySeptember 19-22, 2001, Cleveland,USAPhone : (847) 698-1627Fax : (847) 823-0536http://www.srs.org

The 1st International Symposium onMeasurement, Analysis and Modelingof Human FunctionsSeptember 21 – 23, 2001, Sapporo,JaponPhone: +81-45-924-5654Fax: +81-45-924-5684e-mail: [email protected]://www.ito.dis.titech.ac.jp/ISHF2001/

BIOMECHANICA IV (OrthopaedicResearch Society) September 23- 25, 2001, Davos Suissehttp://www.biosolutions.net/motion_analysis/Biomechanica_IV.htm

4th International Conference on MedicalImage Computing and ComputerAssisted Intervention

October 14-17, 2001, Utrecht, PaysBasPhone: +31 30 250 6695Fax : +31 30 251 3399E-mail: [email protected]://www.miccai.org/

16th Annual Meeting of the NorthAmerican Spine SocietyOctober 31st –November 3rd, 2001,Seattle, USAhttp://www.spine.org/


communicationAgenda

proceeded to describe the ARGOSwebsite, www.argos-europe.com. TheArgos website features the three mainfocuses of Argos: communication,training, and evaluation. The site liststhe association's offices, commissions,organization chart, and contacts andprovides information about Argos-sponsored events. The training sectionoffers a list of training centers whichhost surgeons from the world over, and alist of Argos partners. The next speaker, ProfessorChristopher Ullrich, addressed theissue of information technology andmethods for storing, retrieving, anddistributing medical images. Heoutlined the advantages and drawbacksof five methods.With film-based image dispatching andinterpretation, images are easilydisorganized and lost, and it is difficultto dispatch them efficiently. Videorequire a great deal of storage space andis processed using toxic chemicals thatcontaminate the environment.Electronic image dispatching andinterpretation is fast, dependable, andflexible. Images remain organized. Thishigh resolution medium can be usedwith sophisticated software. However,display equipment is expensive and thismethod generates high infrastructurecosts. Other drawbacks include the factthat this method requires skilledtechnicians; equipment quicklybecomes obsolete; and sophisticatedcomputer tools can be intimidating andcounter-intuitive. PACS is the buzzword that describes thethird approach. Prof. Ullrich explainedthat PACS (Picture Archiving and

Communications Systems) are intendedto be used by a radiology department,not an entire hospital, much less thewhole world. PACS offer easydistribution and data exchange withother hospital departments. However,this system usually requires proprietarysoftware on each display computer thataccesses the system. Moreover, systemsmay quickly grow obsolete and requirelarge bandwidths to handle ever-growing data sets. The fourth approach relies on Internet-related developments. Universal webbrowsers allow user-specificapplications; all upgrades come from acentral server; and multiple users canaccess the system simultaneously. Dueto concern about data security, privacyand security standards are already inplace (firewalls, SSL, VPN, etc.). Application service providers are thefifth and final option. With this system, a«vendor» owns the computer and afacility/hospital enters into a contract touse it. The facility will use a givenvendor as long as the service provided issatisfactory ; otherwise it can switcharound until it finds a satisfactoryvendor. The downside is a certaindegree of loss of local control by thehospital or facility. In his presentation entitled, "To evaluatein order to communicate," Dr. AlexandreTemplier addressed basic issues such as:Evaluation is a continuous andcollective approach; but what is itspurpose? One evaluates for the future,but what is the future of orthopædicsurgery? Evaluation, as a continuousand collective process, is an essentialpart of the surgeon's responsibility as adecision-maker. Dr. Templierunderscored the importance of thecontinuity of assessment throughout theentire clinical process. As the patientgoes through all the clinical steps, fromhis first visit to the doctor to theoperating room, the physician isconstantly analyzing and evaluating:from the pre-operative stages to surgery,(consulting room, diagnosis, tests, X-rays, etc.) to post-operative evaluation.

Depending on the result of surgery, thesurgeon must analyze the reasons forsuccess or failure. Post-operative follow-up is thus a crucial stage of the process,but surgeons still lack adequateassessment tools. Secondly, Dr. Templierunderscored the collective aspect ofevaluation, allowing surgeons to becomefamiliar with each other's standards; thismeans improving communicationbetween surgeons. To this end,prospective multicentric studies can bevery useful. The future of evaluation,according to Dr. Templier, may lie innavigation, if image-guided surgery isimplemented by pre-operativemeasuring and quantifying techniques.Now the question is, will these newtechniques really benefit the profession,or are they a passing fad? The future willtell; nevertheless, one clear point is thattoday's evaluation tools must beclinically relevant, reliable, non-invasive, and easy to use, withreproducible results. Of course, thesetechnological advances will neverreplace surgeon's experience andscientific expertise, but their potentialshould not be underestimated.Ms. Isabelle Lucas Baloup, a lawyerlicensed to practice with the Paris court,delivered a speech on "Internet inmedical and surgical practice in France"from a legal viewpoint. She began byasking, "Is the law the worst enemy ofsurgical progress?" The Internet isinternational, but each country has itsown laws. A physician's use of theInternet in France is governed byFrench civil and penal law, and themedical profession's code of ethics.French law will apply if the informationon Internet is available in France. ■



Dr. Alexandre Templier, PhD

Maître Isabelle Lucas Baloup

ASN:Professor Gracovetsky, canyou describe the path that hasled you to devote your career tothe study of the spine?

SG: I graduated from the EcolePolytechnique Fédérale in Lausanne in1968, with a degree in nuclear physicsand I also obtained a Ph.D. from theUniversity of British Columbia in 1971.My meeting with Harry Farfan in 1974gave me the opportunity to work in thebiomedical field. At that time, Harry wasat the heart of a renewed effort involvinga number of research scientists, such asAlf Nachemson, which culminated inthe foundation, in Montréal, of theInternational Society for the Study ofthe Lumbar Spine which is now the

undisputed leader in this field. Theatmosphere was electric and I wascarried away by this "brainstorm". I thenspent about ten years trying tounderstand the characteristics of a"normal" spine, by means ofmathematical simulations and analysesin the pathology laboratory. The manycontradictions between experimentaldata and the theories of the timegradually led me to reject many widelyheld beliefs and, in 1983, led to theformulation of a hypothesis combiningthe essential aspects of the work of manyauthors into a coherent theory able toexplain the structural and functionaldevelopment of the locomotorapparatus. This was called the "SpinalEngine" theory, which was the subject ofnumerous criticisms, but has never

really been replaced. It thereforeappears to partially correspond toreality. This theory led me to developinstruments to measure clinical spinefunction. One of these instruments,called a "Spinoscope", led to the creationof a company that operated for a numberof years.

ASN:Can you describe your workenvironment before your recentretirement?

SG: I was working in a company called"Spinex", which comprised a very largeresearch department, exclusivelydesigned to develop commercialapplications of our research. Workstarted at the Concordia University inMontréal (Faculty of engineering andcomputer sciences), where I was afaculty member for 27 years. Today, I ammore specifically interested in themedical decision process, i.e. tounderstand the elements which leaddoctors to arrive at a diagnosis for thecause of our eternal nemesis, low backpain. Since 1992, my main areas ofinterest have been expert systems andstructuring of knowledge in order tomore clearly understand why a clinicianadopts one treatment strategy ratherthan another. I have tried to integratespinal function as measured by variousinstruments, with more conventionalmethods such as radiology, painassessment and clinical observations in


evaluationThe Spine Engine

Interview with Professor

S. Gracovetsky

Professor Serge Gracovetsky kindly granted us this interview while he wasin Amsterdam for a university seminar on the biomechanics of the locomo-

tor apparatus.

“The Spine Engine: A unified theory of the Spine?”

“If the leg cannot rotate the pelvis, then what rotates the pelvis ?? It has to be the spine.

But how ??”

Human Gait

What we

want

What we

have



order to establish a multidisciplinaryapproach.

ASN:You mentioned ProfessorsFarfan and Nachemson withwhom you worked. In whatcontext did you conduct thesecollaborations?SG: My collaboration with Harry Farfaninvolved 7 to 8 hours a week and lastedapproximately from 1974 to 1985. Weconducted a large number of studies andpublished many papers together. Harryhad exceptional intuition and vision,extending well beyond conventionalmedicine. He believed that spinalproblems were due to excess mechanicaltorsion. Nachemson, an impulsive andbrilliant man, saw most spinal problemsin terms of disk compression. WhenFarfan and Nachemson were on thesame podium at any congress organizedanywhere on the planet, you could besure of a fierce, and well-reasoned,battle of wits. My own work was greatlyinfluenced by the jousting betweenthese two exceptional personalities. Thespinal engine theory actually representsa compromise between these twoextreme points of view supported byFarfan and Nachemson. This theorydemonstrates the irreducible linkbetween compression and torsionphenomena which are an integral part ofthe principle of human locomotion.

ASN: What are the generalprinciples of your Spinal Enginetheory?

SG: The main idea is that locomotion isan activity which takes precedence to allother activities. The individuals of aspecies must move in order to surviveand enjoy vital bodily freedom.However, we need to define certainlimits to this hypothesis. According to

this theory, the animal must travel frompoint A to point B by consuming aminimum of energy, in a constantgravitational field, with, as a corollary,that while walking, the variousstructures (bone, ligaments and muscles)must be submitted to a minimum ofstress. Anatomy therefore emerges asthe solution and not the given parameterof the problem. All of the possible solutions to thisproblem have led to many anatomicconfigurations, and our anatomy is onlyone expression of these numerouspossibilities. The human body as weknow it today, is mainly the consequenceof the need to effectively walk on twofeet in a constant gravitational field. Thespinal engine oscillates within thisgravitational field.

ASN: What, then,is the role of the

spine in the locomotion?

SG: I consider the spine to be the"primary" engine, in the etymologicalsense of the word. This primary engine,so obvious in our ancestors the fish, hasnot travelled towards the lower limbsover time, although its role has becomemore obscure and may appear to besecondary to the role of the lower limbs.However, this logic is faulty, as we areable to "walk" on our knees withrelatively little adaptation, whichdemonstrates that our legs are not trulyessential to human locomotion. Awooden leg is just as effective. It wouldbe conceivable to cut the femur onecentimeter above the knee withoutsignificantly affecting walking. Thistherefore raises the question: how farcan we cut the femur before affectinghuman locomotion. The answer is thatthe lower extremity can be completely

«Are the legs really

necessary ???»

Compression Torsion

“Pathology gives data on how the spine is used

in life. Any explanation for human gait must

incorporate these pathological findings.”

removed without interfering with theprimary movement of the pelvis. Thisstatement may appear somewhatexcessive, but it is supported by thefacts.

Prof. Gracovetsky then showedus a film on his computer,representing a man with no legsand no stumps walking bysuccessively advancing hisischial tuberosities, as if he hadlegs. The spinal mechanics thenappeared to be the engine of thislocomotion, which appeared toso closely resemble normalwalking.

It is obviously preferable to have legs,but they only amplify the movements ofthe pelvis, and their functional roleremains secondary.

ASN: Can you briefly describethe interrelations between thespine, the pelvis and the lowerlimbs?

SG: The spinal engine is quite obviousin the case of a snake or a lizard, butwhen a high level of power needs to bedeveloped, the muscles of the trunk areinsufficient. To increase the volume ofenergy-generating muscles, they had tobe displaced outside of the abdominalcavity, to the legs. The first role of thelegs is to support the energy sources,which enable us to move at high speeds.However, rotation of the pelvis (as thepelvis rotates around a vertical axiswhen we walk) with muscles whichdraw the pelvis downwards leads to aproblem of efficacy. This problem isresolved by using the earth'sgravitational field as the site ofintermediate storage, in which themuscle energy released by the legs witheach step is temporarily stored and thenrecovered during the monopodal stancephase. This energy impulse thenascends up the leg and is filtered by the

leg, so that it reaches the vertebralcolumn with the appropriate phase andamplitude. The spine can therefore usethis energy to mobilize eachintervertebral joint, and to rotate eachvertebra and the pelvis in an appropriatefashion. Movement of the vertebralcolumn, especially its axial rotationmovement, is therefore derived from thehip extensor muscles.

ASN: What happens in the staticposition?

SG: The anatomic structures whichconnect the spine to the lower limbs areconsiderable. Take biceps femoris or thehamstrings, for example; the forcegenerated by the hamstrings arechannelled by the sacrotuberousligament, which controls longissimuslumborum and latissimus lumborumsituated on either side of the lumbarspine. Part of the sacrotuberousligament then controls the iliocostalisthoracis muscle up to the superior partof the thoracic spine. Two transverseplanes (the right hamstrings control partof the muscles connected to the left sideof the thorax and vice versa) constituteanother direct link between thehamstrings and the superior part of thethoracic spine. Another importantlinking element consists of gluteusmaximus which crosses the medialaspect of the spine to be attached tolatissimus dorsi, which controls arm

movements. All of these connectionsform a sort of cross-pyramid of the back,which ensures very strong mechanicalintegrity from the upper limbs to thelower limbs.

ASN: Can you place theconfiguration of the humanlocomotor apparatus, as weknow it, in the context ofevolution?

SG: The presumed starting point (as it isonly a hypothesis) is that primitive fish,450 million years ago, moved in thesame way as modern fish, i.e. by a lateralinflection movement of the spine. Fishwhich subsequently ventured onto dryland were faced with several problems,the first being to move by planting theirfins into the mud by means of analternating movement. This axialrotation movement combined with thelateral flexion movement resulted in themovements of flexion and extension.Thus, the simple need to move oversmall pebbles led our fish to inventflexion and extension movements. Thissame flexion-extension movementsubsequently allowed galloping and thedevelopment of the lower limbs, as thepara-axial muscles gradually movedoutside of the abdominal cavity tobecome hamstring muscles, in order toincrease the brute power available forlocomotion. Some of these vertebratessubsequently returned to the sea, while



" Only half the available muscle power is used. Each step

advances the animal by one shoulder width "



retaining their capacities for flexion-extension movements acquired duringtheir "stay" on dry land. These animalsare marine mammals, which alsobreathe in a very different way from fish.The hypothesis that these marinemammals are descendants of terrestrialquadrupeds, at their turn descendedfrom marine animals is now generallyaccepted.The inevitable increase in the musclemass of the legs then made an uprightposture possible. Finally, the need toadvance and therefore to pivot the pelvisin two alternating ways, gave rise to thespinal mechanics that we now knowtoday.

ASN: When we listen to youspeak, we have the impressionthat you are neither a doctor, nora biomechanical engineer. Howwould you describe yourself?

SG: I have never thought about it, but I

am certainly proud to have contributedto solving certain problems. Thesolutions that I proposed were thesubject of a great many criticisms,sometimes more destructive thanconstructive, but in the final analysis,the need to reply to these criticisms wasa major element that helped me topresent my ideas more rigorously. It istrue that I sometimes felt that certaincriticisms did not always reflect adisagreement based on good faith, and Isometimes answered in a way that I nowregret.

ASN: Don't you think that yourtheory was the subject of somuch criticism because you didnot belong to any clearlyidentified discipline?

SG: I was not trying to solve theproblem of human locomotion. Manyother scientists more erudite thanmyself possessed the necessary

elements to converge on this vision ofthe spinal engine. Lowett in 1898 (acentury ago!) came close to this solution,but did not take the last step, as itappeared far too incongruous. I can alsothink of people like Farfan, Nachemson,Pope, Winter and many others. All in all,it wasn't my place to find this solution,but rather all these other people whohad infinitely more knowledge andexperience in relation to the spine. I felta need and I saw a gap in the logic ofour knowledge at the time. I was veryyoung when I entered this field (I wasappointed Professor at ConcordiaUniversity in Montréal in 1970), with acertain independence of mind, and Istarted by studying everything that mypredecessors had done. It took me 3years to review thousands ofpublications on the subject, which Irefined to 600 or 700 papers that Iconsidered to be important. There werepapers all over my office: on the floor, incabinets. I was therefore faced withstrong and often divergent opinionsvoiced by honest people and I askedmyself how I could incorporate all ofthese diverging views into an all-encompassing theory, a sort of unifyingtheory, as is often the case in physics.Then, one day in January 1983, Isuddenly had a vision : I saw the spinewalking, a sort of slow-motion film. Ithen had to formulate this vision into atheory which was mathematically soundand publish it, which I did for the firsttime in 1985.

ASN: What are your currentprojects?

SG: I made a lot of errors in the way inwhich systems for the diagnosis of spinaldiseases should be designed. I fought formany years to promote the use of ameasurement platform, which can begreatly improved. When I started, abouttwenty years ago, computers were veryslow, and measurement systems wererelatively inefficient. Currently availablesolutions will inevitably integrate digital

“Solution: Change locomotor design to advance by one body length at each step”

“Lordosis is a unique feature of the human

spine”

“Lateral bending with lordosis induces an

axial torque”

imaging, slightly more advanced toolsfor the assessment of pain, some of thepatient's psychological aspects, andfunction. This should provide a moreaccurate description of the patient,which will obviously not be perfect, butwhich, in any case, would be better thanthe system available at the present time.The decision to perform surgery andevaluation of its impact on all of thelocomotor apparatus are essential, and Iam going to continue to patent severalideas and continue in this direction.

ASN: ARGOS is above all anetwork of orthopaedic surgeonsand neurosurgeons. Do you havea special message for ourmembers and readers?

SG: The diagnosis of spinal diseases,especially low back pain, is problematicin at least 90% of cases. Nevertheless,the current healthcare system expectsthe doctor to find a permanent solutionto an insoluble problem. Healthauthorities need to recognize that lowback pain is a difficult condition todiagnose, and provide appropriateresources to help the medicalprofession. In my opinion, fees formedical procedures concerning low

back pain should be considerably

increased so that the doctor can spend

the necessary time to establish the

preoperative and postoperative

diagnoses using appropriate tools, while

maintaining the same level of income. ■




“The leg transfers the heel strike energy to

the spine. It is a mechanical filter.

The knee is a critical part of that filter

Improper energy transfer will affect spinal

motion

Functional assessment of the spine ought to be

part of the assessment of knee surgery”

“The spine is an engine driving the pelvis

Human anatomy is a consequence of function.

The knee cannot be tested in isolation.

It is part of the overall function and purpose

of the musculoskeletal system”

ContactInformation:Serge Gracovetsky

[email protected] DauphineSt Lambert QC

Canada J4S 1N3

Serge Gracovetsky wishesto acknowledge the

considerable contributionmade by numerous

individuals: N Newman,M Richards, S Asselin,

V. Vidovic, ...

Proximal Facet Preservation i

using a new OMNIPreliminary North A

W.B. Rodgers, M.D. (Jefferson City, MO)

evaluationOMNI-AXIAL Connector

Introduction

DAMAGE to the cephalad facet jointremains one of the technical

difficulties arising from transpedicularspinal fixation systems. We describe anovel OMNI-AXIAL screw-rodconnector for the SCS/CLARIS SpinalClip instrumentation system that allowsgreater offset from the joint and maydecrease late facetal degeneration andresultant post-fusion back pain.Preliminary North American results of aconsecutive series of eighty lumbarinstrumentation procedures (min f/u 3months) using the new connector arereported.

Methods

Static and fatigue laboratory testingwere performed using the CunninghamProtocol on the OMNI-AXIALconnector. Static testing consisted ofstandard sub-construct and fourscrew/connector-rod construct flexionstudies on the Instron 8511. A 25-mmflexion arm was used with loads appliedat 13 N/sec for sub-construct flexion. A45-mm lever arm between load

directions and arms with a 76-mmsuperior-inferior screw distancecomprised the four screw/connector-rodflexion testing. Comparisons were alsomade to existing implant systems.

The OMNI-AXIAL connector wassubsequently used as the cephaladscrew-rod connector in a consecutiveseries of 80 lumbar fusion procedures.Fusions were performed forspondylolisthesis, degenerative diskdisease, recurrent herniated nucleuspulposus, scoliosis, neoplastic andmetastatic disease, and failed ALIF.Forty-two patients had undergone priorlumbar surgery and nine had had priorinstrumentation. Fifty-nine patients

were actively abusingtobacco.

Three patients hadsimultaneous anteriorfusion procedures.Autogenous iliac crestgraft was used in allcases except two.

Demineralized bone matrix(ALLOMATRIX, Wright MedicalTechnology Inc., Memphis, TN) andcancellous allograft was used to augmentthe autograft in sixty-four procedures.Calcium phosphate derived from coral(ProOsteon, Interpore-Cross Int.,Irvine, CA) was used to augment theautograft in eight cases.


Undesired propagation of fusion

(pseudarthrosis) with proximal

facet damage.

Revision. Note proximal

facet preservation.

Case report

43 yo F, 157 cm, 120 kg, gr III

spondylolisthesis

Index Procedure:

L5-S1 fusion with reduction to gr I

Outcome:

9 days post, L5 pedicle fx during

physiotherapy

S1 screw failure

Secondary Procedure:

Revision to L4-S1 fusion

Technical Point:

Reduction requires 2-level fusion

Divergent alar screw augments sacral fixation

n Lumbar Fusion Procedures

-AXIAL Connectormerican Experienceand David R. Lange, M.D. (St. Louis, MO)

evaluationOMNI-AXIAL Connector

Results

Sub-construct testingrevealed rod bending (atmean 53 daN load) prior toany rotational slippage ofthe connector. Fourscrew/connector-rod testingyielded 63 daN loads towithout any connectormovement. Two sampleswere fatigue tested at5,000,000 cycles with 20daN load.Preliminary clinical results(min 3 months, range 3-12months) have beenencouraging with routineprogression toward fusionand no complicationsrelated to the newconnector.

Conclusion

The SCS/CLARIS Spinal Clipinstrumentation system OMNI-AXIALconnector permits caudal displacementof the rod-screw interface. Thistranslation coupled with the narrowdiameter of the transpedicular screwpost permits proximal construct fixationwith minimal damage to the cephaladfacet. Proximal facet preservation maydiminish later post-fusion back pain.

March 2001 - N° 3 ARGOS SpineNews 41

ComplicationsSeroma 2Deep Infection 1Hardware failure 1

DemographicsAge(mean) 54.1 yrsMale 47Female 33Tobacco 59Prior lumbar surgery 42Prior instrumentation9

Diagnosis Primary SecondaryTumor 4DDD 28 24Spondylolisthesis 20 5

Gr I 10, Gr II 7, Gr III 3

Rec HNP 11Failed ALIF 2Pseudarthrosis 8 3Fracture 1 2Scoliosis 6Stenosis 31

The first biomedical

applications of shape memory

alloys (SMA) appeared 20

years ago. Since then,

researchers have been working

on the expanded properties of

these alloys, engineers have

exploited them to develop new

medical devices and surgeons

have spread innovative

surgical techniques throughout

the world.

AS it is now well-established thatalmost 80% of the world-wide

innovative technologies are described inexisting patents, it seemed interesting tosummarize these 20 years of researchand development through aretrospective study ofthe patents issuedin this field since 1978.We will see that specific analysis appliedto a patent database can give precisetechnologic and market trends. Thefollowing statistics have been extractedfrom WPI database (Word Patent Index)which covers more than 20 millionpatents issued in 40 industrializedcountries for 20 years.

Industry segmentsWe have found that 3695 patents havebeen published on SMA since 1978,among which 365, exactly 10%, dealwithmedical applications.Furthermore, the InternationalClassification of Patents reveals whichspecific areas are covered by these 365patents. Among the 3 main biomedicalfields of application of SMA, thebreakdown is: Orthopedics cardio vascular dental45 % 44 % 11 %Tab.1 : Percentage of patents on variousmedical applications of SMA

Publication yearsThe evolution of the number of patentsper year gives valuable informationabout the maturity level of a technology:depending whether the number ofpatents is increasing or decreasing, itmeans that the technology involved iseither innovative or has reach the limitof its evolution.Here, the number of patents isconstantly increasing since 1982, whichproves that the biomedical use of SMAis still growing.

Priority countries

The priority country is the first countryof publication of a patent. Thedistribution of priority countries gives agood indication of the leading nations ina specific technology.It shows the overwhelming leadership ofJapan and United States, with 144 and132 with first publications respectively.

Designated states

The designated states are the countrieswhere a patent is extended between 12and 18 months after its first registration.This gives a good trend of the potentialeconomic markets as seen by thecompanies who publish these patents.It seems that the market is quitebalanced between North America(US+CA – 197 patents) and the Pacific area (JP+AU – 227 patents) and that theEuropean market is considered far lessimportant (DE+FR+RU+GB – 111patent).

Conclusion

This retrospective study based uponpatents’ statistical analysis highlights the


evaluationShape-memory alloys

Retrospective study on medic

applications of shape-memor

Fig.1 : Evolution of the number of patents per year

trends followed by SMA in thebiomedical field :- Japanese and North Americanleadership- increasing development for more than15 years.It can be concluded that despitemanufacturing difficulties, relativelyhigh cost and severe market regulations,shape-memory alloy applications aresuccessfully finding their way to impacta growing number of medical devices.


al

y alloys

Fig.2 : Distribution of priority countries

considering the number of patents published

Fig.3 : Designated countries according to the

number of patents extended

Anne VilleneuveEconomic Intelligence Department

ManagerINNOTECH, Technological

Resources Centre221 avenue du Pdt Wilson,

93214 St Denis la Plaine cedex,France

ARGOS NewsARGOS Member CardThanks to all ARGOS members, the 5th ARGOS International Symposium on thenew technologies dedicated to medical practice had a tremendous success in termsof exchange between participants as well as for the quality of the communicationspresented.To celebrate this event, we are pleasedto offer you the ARGOS Member Card.This card represents first of all a sign ofour gratitude but also the recognition ofyour membership. This strictlypersonal card (renewed every year) canbe used as a badge for our meetingsand it also guarantees certainadvantages to ARGOS Members:• The access to our private forum onthe ARGOS Web Site (www.argos-europe.com) • 20% to 30% discount on car rent with AVIS for your professional and personal useall over the world. This is only the beginning of a longer list of advantages the ARGOS board are justabout to negotiate for you with several international groups.

Spinal Column Pathology Association of Argentina : new authorities We are pleased to inform you that from March 21, 2001 new authorities will betaking office at this important Argentine medical institution. Dr. Horacio Sarrameawill be conducting the Association's new stage of management as its President.

First ARGOS Belgium meetingThe first ARGOS Belgium Meeting was held in Mons, Belgium, on April, 21st 2001under the presidency of Dr Henri Costa, ARGOS Belgium President.The theme of this meeting was: "Surgery & radiography of the lumbar spine : stateof the art".

ARGOS Italian OfficeThe ARGOS board is pleased to inform you that a new ARGOS office is now openfor you in Italy.ARGOS Italian Office Via Capecelatro, 8120148 Milano MIItalyFor more information, please contact the ARGOS Italian office secretaryGina MenegazziPhone/ Fax: + 39 02 36 50 84 19 - [email protected]

Updated E-mail addresses For a more efficient communication between the ARGOS board and the ARGOSmembers, please send your e-mail address to the ARGOS secretary:Marjorie Salé – ARGOS SecretaryPhone: +33 3 21 21 59 64 - Fax: +33 3 21 21 59 70 - [email protected]

Please feel free to contact us whenever you have an interesting topic youwould like us to write about in our journal.

Alexandre Templier Anca MitulescuEditorial Director Editor in [email protected] [email protected]

ASN : Mr. Wolf, could you give ussome information about theTechnion and the Robotics-lab inthe Mechanical EngineeringDepartment (history, structure,direction, activities) ?

AW : The Technion’s campus is locatedin the beautiful city of Haifa,surrounded with natural forest of theCarmel mounting, watching the Haifabay. Technion has been established aftersome years of intense pioneeringactivities, among which Prof. AlbertEinstein was deeply involved. theTechnion opened its doors in 1924,becoming Israel’s first modernuniversity (Prof. Albert Einstein was thePresident of the first Technion Society).The first undergraduate class consistedof 16 students in two areas ofinstruction; Civil Engineering and

Architecture. During the years theTechnion has broaden its research fields,and today, it contains 19 faculties, 40research centers, 11 research institutesand 15 centers for excellence. Statisticaldata from the years 1999-2000 implythat there were 12,700 students learningat the Technion (the number is growingand is expected to reach 15,000 by theyear 2004).The faculty of Mechanical Engineeringwas one of the first faculties established(1948), its aim is to prepare students todeal with challenges in such a way as toenable them to take front line positionsin developing technologies in allindustrial fields as well as dealing withadvanced computer-aided technologies.The student receives a strongfoundation in basic subjects such as:mathematics, physics, computers,dynamics, thermodynamics, flow theory,strength and control theory. The facultyoffers a number of areas of specializationwhich include a varied list of electivecourses, such as: advanced design andmanufacturing, robotics, mechatronics,electro-optics, computer systems,micromechanics, energy, automation,control nuclear energy etc. The robotic laboratory is one of twelvelaboratories in the J.W. Ullman Centerfor Manufacturing and Robotics (Head:Prof. Moshe Shpitalni). The head of thelaboratory is Prof. Moshe Shoham. The

robotic lab focuses on developinganalytical and mathematical tools for thedesign and analysis of robots in general.Few years ago, we were one of thepioneer groups to specialize in specialtypes of robots called parallel robots.

ASN : What are your currentprojects in computer-aidedorthopaedic surgery ?

AW : We have several projects in our labregarding medical applications. At thebeginning, in order to examine thefeasibility of using a robot manipulatorguided by a pre-operative ComputerAided Design program for medicalapplications, a surgical tool and a forcesensor were attached to an existingcommercial robot . Based on the pre-


trainingTechnion’s Robotic Lab

Orthopaedic Surgery &

Robotics at the

Technion’s Robotic Lab

Alon Wolf (M.Sc), PhD Student in the Robotics Lab at the Mechanical Engineering Department ofthe Technion (Israel Institute of technology). In this article Mr. Wolf gives us some input about

current projects, and new developments of the robotics lab. His particular work is focused on spi-nal surgical procedures, which could be usefully assisted by robotics technologies. The design of a

micro-robot for spine surgery is in progress.

Bone shape by

a robot to fit

an implant for

total knee

replacement

Pre-operative planner for total knee

replacement



operative planner, the robot was able toshape a bone, under controlled force, tofit a given implant for the total-kneereplacement procedure. One of theresults of this research was that we haveidentified parallel - structured robot asbest suited for medical applications. Asan outcome, a prototype of a parallel sixdegrees-of-freedom robot (RSPR3) hasbeen constructed for manipulating alaparoscopic/arthroscopic camera inminimally invasive surgeries. We havealso held an investigation in which anefficient registration method for robotic-assisted surgery was developed.Registration is a critical stage, in whicha geometric relationship such asposition and orientation of the patient’sbone relative to the robot’s tools isestablished intra-operatively. Currentregistration techniques often needimplantation of artificial fiducialmarkers or digitizing devices such asoptic or magnetic sensors or laserscanners, which complicate theregistration procedure. We developed aregistration process using a surface

matching technique, which does notrequire any marker implantation. In thisresearch, we used the robot itself as adigitizer eliminating the need for anextra localizer.In another work by Prof. Charit wedefined the geometry of knee and hipjoints and designed a new obliqueosteotomy technique for leg Perthesdisease.The last project related to computer-aided orthopaedic surgery is for spineapplications. In this work we develop amini-light-weighted robot for spinaloperation procedures. The roboticsystem is designed to work in a semiactive and active operational mode,meaning for guidance of the medicaltool during operation, at first and lateron for performing an operationprocedure actively. The robot isregistered to a 3D spinal model, builtfrom CT, MRI, or Fluoroscopic personaldata of the operated patient. We havealready held few preliminaryexperiments in which the concept of therobotic system has been testedsuccessfully, and the first robot is nowbeing built and should be testedclinically before June 2001. The Israeliministry of science sponsors thisresearch, and we cooperate with Pr. LeoJoskowicz from the Hebrew Universityof Jerusalem. For the entire project ofmedical robotic systems we collaboratewith many orthopedic departments inIsraeli hospital, especially with theCarmel-Hospital OrthopedicDepartment headed by Dr. Moshe

Roffman.

ASN : What are the mainnon-confidenciel projectsof your laboratory in thenext 5 years ?

AW : Beside spinal applications(which are mostly confidential, asthey are currently in a stage ofpatent), and knee surgery, we arebeginning to focus on other newmedical fields, such as eye

surgery, dental, and invasive microautonomic robots, to operate forexample in the blood stream and thedigestive-system. We are alsodeveloping new robotic techniques forMEMS applications ; this researchcalled “the factory of the Future” issupported by the Israeli-Frenchministers of science, and we cooperatewith Prof. Jean-Pierre Merlet fromINRIA Sophia Antipolis.

ASN : Today Robotics suffersfrom a bad image amongOrthopaedic Surgeons. Do youthink this could change in thenear future, and if so, how?

AW : Indeed robots suffer from a “badimage” among some orthopaedicsurgeons, my opinion is that it is due toa lack of knowledge and in a way to asociological barrier, and a fear from amechanical device that is sometimessuperior to human ability and perhapscan overcome and replace us. Observingrobots troughout their short history,they have been a threat to human beingsand were not fully accepded. The word“Robot” entered common usage withthe publication of the first play RossumeUniversal Robots by Karel Capek, aCzechoslovakian, who published this in1921. It was a parody on utopian society,where machines performed allunpleasant work and man was free toenjoy a life of leisure. In the vision of theFuture created in motion pictures,robots were and are automatic systemsthat respond to do man’s bidding andoccasionally, of course, becomebelligerent turn into of their master.Such activities provoked a fear frommachines in the minds of the lay publicand led the creative author Isaac Asimovto develop his “Three Laws ofRobotics”, published in 1942:1. Robots may not injure a human being,or, through inaction, allow a humanbeing to come to harm.2. A robot must obey the orders given itby human being except by such ordersRegistration process

6-DOF parallel robot

for laparoscopic/Arthroscopic

that would conflict with the first law.3. A robot must protect its own existenceas long as such protection does notconflict with the first or second law.In my opinion, robotic systems shouldbe integrated into operationalprocedures in such a way that will notprovoke any fear from loosing control,hence those systems should provide fullcontrol during operation to thephysician in charge. Rather thanworking in an active mode (where therobot performs actively operationalprocedures), the robots should work, atthe beginning, in a semi-active mode, ora passive mode. In the first mode, therobot acts as an assistant during theoperation. The robot could do that byholding a tool in a steady position,guiding accurately cut tools, or bypreventing the operation tool to moveout of the desired operative region. Inthe passive mode, the robot is fullycontrolled by the surgeon; this mode isusually used for teleoperation (as waspresented in the 5th Argos symposium).Another important thing is that roboticsystems should not be forced to

operational procedure but only to thoseprocedures where they are clearlysuperior to the human hand. Forexample: a robot could follow a path(curve in space) much more accuratelythen a human hand. It has very goodrepeatability ability, it can perform verydelicate tasks (such as microscopictasks), and of course, it can bedownloaded with real time information

from a computer system. By providingthe robot with real time information, ithas no need for a view of the operationarea, hence it could be used inpercutanoues procedures (e.g. forguiding).

ASN : You have applied tobecome a member of ARGOS. Doyou already have something tosay, or an announce to send toour members or readers?

AW : I believe that the three primepurposes of ARGOS (Communication,Training, Assessment) are veryimportant and in order to drivemedicine forward corporations andshare of knowledge should be carrieddaily. I hope that ARGOS will broadenits activity and that ARGOS’ memberscould assist, advise, and give a feedbackto each other in a constructive way. Weat the robotic lab are willing tocooperate and advise others in aspectsrelated to our specialties. ■




A simulated endoscopic task

6-DOF Stewart

platform for MEMS

6-DOF parallel robot

Contact Information :Robotic Lab

Technion, Israel Institute of TechnologyMechanical Engineering Department

Haïfa, Israël 32000

Tel : +972-4-8293264 [Moshe Shoham] /+972-4-8293169 [Alon Wolf]Fax : +972-4-8324533Email : [email protected] [MosheShoham][email protected] [Alon Wolf]Website : http://robotics.technion.ac.ilTeam Members : Pr. Moshe Shoham, Alon Wolf, NabilSimaan, Michael Burman

Prof. Moshe Shoham

www.caos-international.org

The International Society for Computer

Assisted Orthopaedic Surgery

(abbreviated "CAOS-International")

The purpose of The InternationalSociety for Computer AssistedOrthopaedic Surgery, a non-profitorganization, is to bring together thoseindividuals throughout the world, who,by their contributions and activities inthe areas of research, clinical study, andclinical use, have indicated or areindicating interest in computer assistedorthopaedic surgery.Its further purpose will be to serve as aforum for the exchange of information ofboth an investigative and clinical nature

which relates to preoperative planning,intraoperative execution andpostoperative follow up by means ofcomputer assistance.

Finally, the Society aims to promote anew partnership between orthopaedicsurgeons and technologists as anecessary basis for the successfulintegration of computer assisted surgicaltools and techniques into the dailyclinical routine.CAOS-International will seek toaccomplish these goals by holding oneannual meeting and related workshopsand by disseminating information to it asan organization either at these meetingsor independently, by stimulating basicand clinical research, and by organizingpostgraduate teaching programs andassisting Universities in developinggraduate and post-graduate teachingprograms.

The Society shall collaborate and co-operate with other associations andbodies whose efforts are directed at thesame objectives and whose interest areallied with or are similar to those of theSociety itself.

www.iscas.org

The International Society of Computer

Aided Surgery

The aims of Computer Aided Surgeryare to advance the utilization ofcomputers in the administration oftreatment to patients, to evaluate thebenefits and risks associated with theintegration of advanced digitaltechnologies into surgical practice; toprovide a means to disseminate clinicaland basic research relevant tostereotactic surgery, minimal accesssurgery, endoscopy, and surgicalrobotics; to encourage interdisciplinarycollaboration between engineers andphysicians in developing new conceptsand applications; to educate cliniciansabout the principles and techniques ofcomputer assisted surgery andtherapeutics; and to serve theinternational scientific community as amedium for the transfer of newinformation relating to theory, research,and practice in biomedical imaging andthe surgical specialties. The scope of Computer Aided Surgeryencompasses all fields within surgery, aswell as biomedical imaging andinstrumentation, and digital technologyemployed as an adjunct to imaging indiagnosis, therapeutics, and surgery.Topics featured include frameless aswell as conventional stereotaxicprocedures, surgery guided by


internetWeb review

Web reviewOrthopedic surgery appears on the internet in a variety of contexts ranging from academic institutionalwebsites and websites for commercial ventures to personal webpages for individual surgeons. Educationalmaterial and product information is now avalaible around the clock.

ultrasound, image guided focalirradiation, robotic surgery, and othertherapeutic interventions that areperformed with the use of digitalimaging technology.

www.ista.to

The International Society for Technology

in Arthroplasty

ISTA grew out of a series of annualinternational symposia first held inGermany in 1988, focusing on thedevelopment of custom prostheses forarthroplasty. The society was formallyincorporated in Switzerland in 1990 asthe International Society for the Studyof Custom Prostheses (ISSCP) followingthe meeting in Nice. As the society'shorizon expanded to encompass abroader range of interests, the name waschanged to ISTA in 1994.

It is composed of surgeons, basicscientists, engineers, andrepresentatives of industry, and itspurpose is to promote interdisciplinaryadvances in the science and technologyof joint replacement. ISTA sponsors anannual symposium designed to foster anexchange of information andcooperation in research efforts on aninternational level. It is governed by aboard of directors with world wide,multi-disciplinary representation.

www.ors.org

The Orthopaedic Research Society (ORS)

was founded in 1954 and incorporated asa non-profit organization in 1982. Thepurposes of the ORS are to promote,support, develop and encourage researchin orthopaedic surgery, musculoskeletaldiseases, musculoskeletal injuries anddisciplines related thereto; to provide,encourage, develop and sponsoreducational activities related to theforegoing; and to provide forums fordissemination of knowledge in thesefields. The intent of these efforts is toimprove the care of patients withmusculoskeletal diseases and injuries. TheSociety has approximately 1,700members. Activities of the Society toserve its stated purposes include anAnnual Meeting and publication of theJournal of Orthopaedic Research in whichthe musculoskeletal communitycommunicates the current state oforthopaedic research.

www.med.unimarburg.de/orthop/eors

European Orthopaedic Research Society

Registered in München, 1991, thisservice was established to promotecommunication among and betweenmembers and the EORS office inMarburg, Germany.

www.issls.org

The International Society for the Study

of the Lumbar Spine

The purpose of The InternationalSociety for the Study of the LumbarSpine, a non-profit organization foundedin 1974, is to bring together thoseindividuals throughout the world, who,by their contributions and activities bothin the area of research and clinicalstudy, have, or are indicating interest inthe lumbar spine in health and indisease.

Its further purpose is to serve as a forumfor the exchange of information of bothan investigative and clinical naturewhich relates to low back pain anddisability.


internetWeb review


ChristianMazel, MD

President

Jean-Paul

Forthomme, MD

Vice President

AlexandreTemplier, Msc, PhD

General manager

PierreKehr, MD

Executive secretary

AlainGraftiaux, MD

Treasurer

Communication committee

Training committee

Evaluation committee

WafaSkalli, PhD

President of thecommittee

JacquesDe Guise, PhD

MichelDutoit, MD

AlainGraftiaux, MD

ChristianMazel, MD

Juan AntonioMartin, MD

HenryJudet, MD

PhilippeBedat, MD

PierreKehr, MD

Charles-MarcLaager, PhD

Jean-PaulForthomme, MD

HenriCosta, MD

Jean-PaulSteib, MD

President of thecommittee

Jean-PaulForthomme, MD

FranckGosset, MD

FrançoisLavaste, PhD

RichardTerracher, MD

Jean-MarcVital, MD

OOrrggaanniizzaattiioonn cchhaarrtt

ARGENTINA Dr Ivan R. AYERZADr Juan Pablo BERNASCONIDr Pedro Ariel COLLDr Alysudro Cesar D'INNOCENZODr Osvaldo FERNANDEZ BOANDr Frederic J. GELOSIDr Felipe LANARI ZUBIAURDr Aroldo Carlos LEGARRETADr Jose Luis MONAYERDr Luis A. PATALANODr Pablo PLATERDr Victor G. RAMANZINDr Gustavo RAMIREZDr Roberto Carlos RODRIGUEZDr Victor ROSITTODr Gabriel ROSITTODr Tomas RÜDTDr Jorge Guillermo SELSERDr Eduardo SEMBERDr Pablo Mario SIRNADr Carlos A. SOLADr Eduardo Angel SOSADr Roberto Gustavo ZISUELA

BELGIUM Dr Henri COSTADr Guido DELEFORTRIEDr Damien DESMETTEDr Sabri EL BANNA*Dr Jean-Paul FORTHOMME*Dr Jean LEGAYEDr Frédéric MATHEIDr Yves RYSSELINCK

BRAZIL Dr André Rafaël HÜBNER

CANADA Pr Jacques DE GUISE*

CHINA Pr John LEONG

EGYPT Dr Talaat EL-HADIDI

FRANCE Dr Joseph ABIKHALILDr Pierre ANTONIETTIPr Claude ARGENSONDr Xavier ARTIERESDr Mohamed Kamel BENCHENOUFPr Robert BOUVETDr Emmanuel BRAUNDr Ihem CHERRAKPr Denis CORDONNIER*Pr Alain DEBURGEDr Jean-François DESROUSSEAUX*

Pr Jean-Claude DOSCHDr Ing Raphäl DUPUISDr Brice EDOUARDDr Gilles GAGNADr Franck GOSSET*Dr Alain GRAFTIAUX*Dr Pierre GUIGUIDr Michel GUILLAUMATDr Pierre HEISSLERDr Etienne HOVERKADr Yves JABYDr Henri JUDET*Pr Pierre KEHR*Pr François LAVASTE*Dr Jean-Philippe LEMAIREDr LEONARDPr René LOUISDr Jean-Luc MARMORATDr Christian MAZEL*Dr Serge NAZARIANPr Michel ONIMUSDr François PODDEVINDr Stéphane RAMAREDr Olivier RICARTPr Gérard SAILLANTDr Jacques SENEGASPr Wafa SKALLI*Dr Joël SORBIER*Pr Jean-Paul STEIB*Dr David Hamid TALEGHANIDr Ing Alexandre TEMPLIER*Dr Richard TERRACHER*Pr Jean-Marc VITAL*

GERMANY Dr Jens DANNENBERGDr Ferdinand KRAPPELPr Andreas WEIDNER

GRECE Dr Panagiotis KOROVESSISDr Demetre KORRES*Pr George SAPKAS

HUNGARY Dr Zoltan CSERNATONYDr Tamas ILLES*

ISRAEL Dr CASPIDr Moshe SHOHAMDr Alon WOLF

ITALY Dr Flavio BADODr Paolo BONACINADr Luigi CATANIDr Ing Moreno D'AMICOPr Vincenzo DENARO

Dr Charles-Marc LAAGER*Dr Tonino MASCITTIPr Giovanni PERETTI*Dr Carlo PIERGENTILIDr Dario RODIODr Michele Attilio ROSA

JAPAN Dr Akira DEZAWADr Kiyoshi KUMANODr Jun-Ichi KUNOGIDr Nobuaki TSUNODA

LUXEMBOURG Dr Adrien WIJNE*

POLAND Dr Daniel ZARZYCKI

PORTUGAL Dr Joao CANNASDr Luis DE ALMEIDA

ROMANIA Pr Mihai JIANU

SENEGAL Dr Seydina Issa Laye SEYE

SLOVENIA Dr Samo K. FOKTER

SOUTH AFRICA Dr Johan WASSERMAN

SPAIN Dr Fernando ALVAREZ RUIZDr Diego BRAGADO NAVARRODr Sergio CABRERA MEDINADr Alfonso CAMPUZANODr J.M. CASAMITJANA FERRANDIZDr J. Ignacio CIMARA DIAZDr Jose Maria CORBACHO GIRONESDr Alvaro DE BLAS ORLANDODr Jose Antonio DE MIGUEL VIELBADr Angel Jorge ECHEVERRIBARREIRO*Dr Manuel FERNANDEZ GONZALEZDr Fernando FERNANDEZ MANCILLADr Frederic FONT VILADr Luis Antonio GARCIADr Antonio GIMENEZDr Francisco GONZALEZDr Ernesto GONZALEZ RODRIGUEZDr Angel GONZALEZ SAMANIEGODr Cesar HERNANDEZ GARCIADr Carlos HERNANDO ARRIBASDr Eduardo HEVIADr Juan HUERTADr Alberto ISLA GUERRERODr Manuel LAGUIA

Dr Rafael LLOMBART AISDr Juan Antonio LOZANO-REQUENADr Carlos LUNADr Antonio MARTIN BENLLOCH*Dr Jose Ignacio MARUENDADr Cesar PEREZ JIMENEZDr Enrique RODA FRADEDr Manuel SANCHEZ VERADr Miguel SANFELIU GINERDr Hugo SANTOS BENITEZDr Jose Luis SOPESEN MARINDr Agustin VELLOSO LANUZADr Javier VICENTE THOMASDr Julio Alfonso VILAR PEREZ

SWITZERLAND Dr Philippe BEDAT*Pr Michel DUTOIT*Dr Bernhard JEANNERETDr Denis KAECHDr Thomas Walter LUTZDr Thierry SELZ

SYRIA Dr Taha ALOMAR

THE NETHERLANDS Dr Willem F. LUITJES

TUNISIA Dr Mohamed Habib KAMOUNDr Fathi KHOUADJADr M. Fethi LADEBDr Mondher M'BAREKDr Mongi MILADI*

UK Dr John P. O'BRIENDr Constantin SCHIZAS

USA Dr Michael ALBERT

Dr Fabien BITAN*Dr Jean-Pierre FARCY*Pr Kamal IBRAHIMDr Eric JONESDr David LANGEDr Vincent J. LEONEDr Robert W. LOWEPr Joseph MARGULIESPr S.M. REZAIANDr William RODGERSDr Michael SCHNEIERDr Michael L. SWANKDr Kostas P. VELIS

* Full members being entitled tosponsor


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