Biomedical Brochure

8/10/2019 Biomedical Brochure

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Solutions for Biomedical Testing

SolutionsforBiomedicalTesting


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BiomaterialsPages 18 - 23

BiomechanicsPages 16 - 17

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Longer life expectancy, an increasingly active population and

scientific advances are fueling a tremendous demand for new

and improved biomedical devices and materials. As technology

evolves, researchers and manufacturers face the enduring task

of delivering biomaterials and products that combine high

quality with life-long performance.

Biomedical testing allows the performance and compatibility of

new materials and medical devices to be proven in vitro,

without putting patients at risk, and for the evaluation of critical

and complex issues in a controlled and repeatable manner.

In addition to helping new products meet essential regulations

such as Food and Drug Administration (FDA) compliance,

biomedical testing allows the quality of medical products to be

verified in a production line, and the development of new and

innovative solutions in the laboratory.

This brochure outlines some of the testing challenges facing

different sectors of the biomedical community and how they are

successfully addressed using Instrons BioPulsTM solutions. As

you read further, youll get a sense of how Instron can help you

with your research and bring your own products to market and

improve the quality of life for the people who use them.

Spine TestingPages 13 - 15

Hip TestingPages 6 - 8


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Instron is proud to be setting the pace in the dynamic and

broad biomedical testing industry. Today, Instron's unmatched

knowledge and experience are reflected in our BioPuls TM

range of application-centric solutions. These unique testing

innovations advance the understanding of material properties

and performance across a vast spectrum of biomaterials and

medical products.

Instron has engineered the BioPuls range to be the most

advanced solution for biomedical testing challenges. With

demands as diverse as low force testing on native tissues to

complex multiaxial simulation of spinal segments, we have

ensured that our products best fit the needs of individual

customers and provide many years of superior performance.

With no compromises on quality or performance, the BioPuls

designs reflect Instron's leading product design philosophy,

where data integrity, safety and protection of investment are

paramount. Whether you are engaged in cutting-edge

research or critical quality assurance on the production floor,

there is a BioPuls testing solution available from Instron.

Application Excellence

Instron's global team of biomedical applications specialists and

professional engineers delivers an array of BioPuls turnkey solutions for

biomaterials, orthopaedics, biomechanics, medical devices and dental

testing. Our dedicated Biomedical Applications Team continues to

advance their application knowledge and experience through strongcustomer relationships, active participation on standards committees

and conference attendance.

Testing Leadership

Since 1946, Instron has been the leading provider of testing equipment

for every kind of material and structure. For decades, our experience

and global perspective has enabled us to be at the forefront of

biomedical testing.

Global Support and Service

Today, Instron has offices in 17 countries and a staff of over

1200 dedicated professionals who speak more than 20 languages.

Instron offers an extensive range of calibration and verification services

and is supported by a vast network of field service engineers.

The Benchmark for Quality

Instron develops its solutions with systems, measurement standards and

procedures that meet or exceed the requirements of standards such as

ISO 9001. With focus on our customers our quality standards are second

to none.

A Rewarding Partnership

We understand the challenges you face, and we will help you meet them.

With a commitment to ongoing product development, compliance to

standards and uncompromising quality, BioPuls is your ideal partner for

materials testing today and in the future.


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Decades of success in using orthopaedic implants for the

restoration of normal function to arthritic joints and for

post-trauma stabilization and repair, has led to a proliferation

of new materials, designs and applications. Dozens of joint

replacement products, most commonly for the hip, spine and

knee joints, are available on the market. As they represent

the most complex mechanical systems in the body,

articulating joints provide implant designers with many

challenges to overcome. Most notably, designers must apply

their knowledge of joint kinematics and loads to their designs

to ensure life-long performance. Physiological forces

dependent on the patient's body weight and physical

activities, motions in up to six degrees-of-freedom, and the

need for a near frictionless bearing surface, are all taken into

consideration in attempts to replicate the joint. In addition,

the effects of stress shielding and wear must be studied and

the service life of the implant in vivo must be verified. All this

fuels a fast-growing need for more complex and anatomically

correct testing protocols.

Instron in Orthopaedics

Instron's experience of testing in orthopaedics is considerable: from

basic static testing of raw materials, to impact loading of joint

components, through to complete simulation for evaluating the fatigue

and wear properties in vivo. Through every phase of implant

development, Instron's innovative BioPuls solutions meet a vast array

of demands found within the orthopaedics field. Offerings include theunmatched Dual-Station strategy of simulator accessories that

significantly reduces testing time when carrying out long-term wear

and durability tests.

This section highlights the range of orthopaedic applications Instron is

actively involved in with its customers.

d

BioPuls Dual-Station ISO hip simulator


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Hip Simulation

The Challenge

Wear of Total Hip Replacements (THR)has been identified as one of the major

causes of osteolysis and consequently

implant failure. ASTM F 1714

Standard Guide for Gravimetric Wear

Assessment of Prosthetic Hip Designs

in Simulator Devices was developed

to evaluate the wear properties of

ceramic and polymeric materials

used as bearing surfaces in hip joint

replacement prostheses. It represents

a more physiological simulation than

basic wear-screening tests such as pinor ring-on-disk.

d

The BioPuls Dual-Station ASTM hip simulator on an

8874 system. The axial-torsional actuator, in

combination with the fixture, generates four-axis

motion in the upper wear station.

Our Solution

The BioPuls Dual-Station ASTM hipsimulator incorporates the gravimetricmethod as per the ASTM standard. It providesan accurate and cost-effective solution forfour degrees-of-freedom hip wear simulationand is offered as an accessory for the 8874axial-torsional test system.

The system applies physiologicallyaccurate loads and motions in axialflexion-extension, abduction-adductionand internal-external rotation on a testspecimen maintained under in vivoconditions. Easy system control isenabled through Instron's user-friendlyinterfaces and fatigue software.

Plot of Wear (mg) Against No. of Cycles

(Gravimetric Method)

Plot of Wear (mg) Against No. of Cycles

(Wear Debris Collection)

Wear results consistent with clinical performance

To conform to ASTM requirements, hip wearsimulators must use two specimens; one testspecimen and one control specimen. Thisstrategy is necessary to eliminate possibleerrors due to fluid absorption into thespecimen or those associated with creep of thebearing materials. Instron's unique Dual-Station design enables simultaneous testing ofboth specimens, a solution whose simplicityand flexibility is unmatched. Without Dual-Station capability, both specimens must eitherbe tested in series, taking over four months tocomplete a single test, or occupy two testsystems in parallel.

The 8874 is aversatile testsystem that inaddition to thelong-term wearsimulation tests,can be easilyreconfigured toaccommodate a full range

of other biomechanical tests.

d

d

BioPuls Dual-Station ASTM hip simulator CADmodel with upper wear station and lower

control station.


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The Challenge

With the vast array of differing hipimplant designs and materials available

in the market, the ISO 14242 standard

Implants For Surgery - Wear Of Total

Hip Joint Prostheses creates a common

platform for evaluating wear

performance. It details a strict set

of testing parameters including

load/ motion profiles, implant

alignment, the conditions for

environmental simulation and a defined

test procedure. The standard also

specifies clear methods formeasurement of implant wear.

dBioPuls Dual-Station ISO hip

simulator on 8874 system

Our Solution

The BioPuls Dual-Station ISO hip simulatorwas designed to address the more demandingrequirements of ISO 14242. The simulator isoffered as an accessory for 8870 test systems,providing a unique approach for hip weartesting that conforms to the requirements ofboth the ASTM and ISO standards.

Unlike other standards, ISO specifies that thehip motions must be generated by the femoralhead, not the acetabular cup, a commonfailure with other hip simulator designs.Femoral and acetabular components mustalso be mounted in the physiologicalposition - the femoral head distal tothe acetabular cup. This BioPulssimulator system generatesphysiological load/ motioncombinations as defined by theISO standard to permit accurategeneration of wear of thehip implant.

The BioPuls ISO simulator was designed

around Instron

's unmatched Dual-Stationstrategy, allowing users to increaseboth productivity and flexibility.Both stations feature environmentalbaths for accurate simulationof in vivo conditions.

d

BioPuls ISO hip simulator. The wear test

station generates loads and motions within

the femoral head.

d

BioPuls Dual-Station ISO hip simulator CAD model

with upper control station and lower wear station.


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Our Solution

A static test based on ISO 7206-9 characterizesthe ability of a femoral head, whether ceramicor metallic, to resist torques normallyassociated with implant use in vivo. The testtakes place in an environmental bath filledwith deionized water and maintained at atemperature of +37 C . While applying astatic compressive preload a transverse torqueis ramped until the head begins to rotate.

The BioPuls fixture accommodates both

metallic and non-metallic hip implants, andis suitable for a wide variety of geometries.

Our Solution

ISO standards have been established to test for

both abnormal and normal fatigue loading.

g The ISO 7206-4 standard simulates

loading when proximal loosening has

occurred. Loads are applied through the

femoral head of the hip implant to

induce compressive, bending and

torsional stresses.

g The ISO 7206-6 standard examines fatigue

of the implant neck, which is more

consistent with a correctly fixed implant

subjected to normal in vivo loading.

The BioPuls femoral fatigue fixture was

specifically designed to meet and exceed therequirements of the ISO tests. The fixtureincludes a low friction loading head andadapters for mounting to the 8870 fatiguesystem. The fixture can also be easily adaptedto suit other test machines and test set-ups.The flexible specimen holder is also providedto accommodate a wide variety of hipgeometries, offset angles, embedding materialsand embedding depths.

The fixture also accommodates an

environmental chamber for complete invivo simulation.

Modular Hip Implants

Femoral Components

The Challenge

After surgery involving modular hipimplants, the detachable head must

remain immobile on the stem as the

patient recovers and returns to normal

levels of activity. Motion of ceramic

heads will cause wear of the metallic

stem, while fretting of metallic heads

can cause stress corrosion. Either

condition will lead to premature

implant failure.

The Challenge

Following surgery, proximal loosening

and stress shielding can occur as a

result of normal activity and can lead to

abnormal loading profiles. Fatigue

testing of hip implants is used to

determine the endurance properties by

simulating the dynamic loading of the

implant during gait.

d

The embedding fixture ensures correct implant

alignment for the test

d

BioPuls femoral fatigue fixture using patented

DynacellTM

load cell technology

d

BioPuls axial-torsional grips with quick latch

environmental bath


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systems, all stations are subjected to identicalload and motion conditions, allowingcomparative studies for the evaluation of thefriction and wear properties of the implants.Each test station is instrumented separatelyand can simulate the soft tissue restraintsassociated with the preservation or resectionof ligaments.

Individual microprocessor-controlledpumping systems for joint lubrication are

used for each test station. This criticaldesign feature allows for wear debriscollection and measurement without riskof cross-sample contamination.

Our Solution

The Instron Stanmore knee wear simulator isunique in its ability to simulate physiologicaland mechanical conditions in the knee joint toproduce clinically relevant and accepted wearresults. The simulator was originally designedby University College London (UCL)Department of Biomedical Engineering atStanmore Royal National OrthopaedicHospital, under the guidance of ProfessorPeter Walker, and is now manufactured,serviced and supported by Instron. It was

designed specifically to allow development ofthe draft ISO standard ISO/TC150/SC4Wear of Total Knee Joint Prosthesis, Loadingand Displacement Parameters for Wear TestingMachines and Corresponding EnvironmentalConditions for Test, now released asISO 14243.

The high-productivity design allowsmultiple knee implants to be tested atthe same time. The simulatorapplies controlled forces inthe axial, anterior-posterior

and interior-exterioraxes, while applying aflexion-extension motion,under the Grood and Suntayjoint models. With common drive

Knee Simulation

The Challenge

Total Knee Replacement (TKR)for arthritic and degenerative conditions

of the knee is a successful and

cost-effective therapy. It is being

conducted with greater frequency

due to increased life expectancy as

well as extension of the therapy to

younger patients. Despite its success,

failures still occur, with wear of

implant materials being a major

contributing factor.

Knee joint simulators seek to replicate

the physiological and physical

conditions that affect the wear process

in order to determine the mechanical

limits of the materials and designs used

in the implant. Time-varying forces of

realistic levels must be applied to the

artificial knee joint while the simulator

flexes, extends and rotates the joint

cyclically over long periods.

d

The four station Instron Stanmore knee simulator

d

Knee implant is subjected to four

controlled and two unconstrained

degrees-of-freedom


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Our Solution

The BioPuls Dual-Station knee simulatorprovides both force and displacement control

to exceed the current ISO 14243 testingrequirements. This simulator combines thesame proven kinematics as the Instron

Stanmore knee simulator with the advancedfeatures of the 8870 test systems and 8800controller. The result is greater control,

repeatability and flexibility for future tests.

The unit applies physiologically accurate loads

and ranges of motion on a test specimen whilein an environmental bath maintained at+37 C. A multiaxis load cell is incorporatedto fully characterize and control specimen

loads. A universal mounting arrangementaccommodates fixtures for a variety of kneedesigns, including mobile, condylar andhinge types.

The Challenge

As biomechanical research into kneeimplants becomes more advanced,

there is an increasing demand for full

simulation of knee kinematics.

With demands for more flexible

simulation, much higher accuracy than

comparative studies is often required, as

well as the capability to test in both force

and displacement control. There is also

much interest in subjecting knee

implants to conditions normally

associated with severe gait loads and

motions, such as those induced from

running or stair climbing.

d

BioPuls Dual-Station ISO knee simulator allows both force and displacement control

To conform to ISO requirements, knee wearsimulators must use two specimens: onetest specimen and one control specimen.

This strategy is necessary to eliminatepossible errors due to fluid absorption intothe specimen or those associated with creepof the bearing materials. The uniqueDual-Station design of the BioPuls simulatorallows a control specimen to be tested

simultaneously with the test specimen,reducing test time significantly.

While principally intended for the study ofknee joint wear, the simulator can also test forother failure modes such as fatigue failure ofstressed components, advanced laxity studies

or dislocation of the implant. The 8870 testsystem can be easily converted to a standardtest frame for other types of testing. Thisincreases the versatility of the test system andallows the full range of biomechanical andbiomaterial tests to be conducted.

d

Wear test station subjected to four controlled

and two unconstrained degrees-of-freedom


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Our Solution

An Instron axial-torsional 8874 system withthe addition of an anterior-posterior actuatorallows researchers to conduct in vitro testson the internal/ external rotation andanterior/ posterior translation stability of theknee joint while it is subjected to normal gaitloads. The effects of component and ligamentmisbalance on the passive stability of theknee joint can then be assessed.

The additional actuator and fixturing can

be removed from the integral T-slot table toallow other accessories to be used foradditional tests. This offers the

ultimate in flexibilityfor biomechanical laboratoriesthat perform a variety of tests.

Passive Stability

The Challenge

Total Knee Replacement (TKR) allowsthe damaged and degenerated articular

surfaces of knee joints to be replaced

with prosthetic components. The laxity

of the knee joint can be affected by the

partial removal of ligaments and other

soft tissue constraints. Excess laxity

places soft tissue under abnormal

strains, causing instability in the joint

and ultimately, joint failure. If the knee

is too rigid, the patient will not have a

normal and comfortable range of

motion. An optimum level of knee laxity

is desired.

d

An 8874 system with anterior-posterior actuator allowing laxity

and tribology studies to be conducted

d

Knee implant fixture on an 8874 system

(Photo courtesy of Southampton University, UK)

A reliable mechanical model and test systemthat can assess the passive stability and laxityof a knee joint is a valuable tool in the designand selection of the optimum replacementknee. Surgical techniques andinstrumentation can also benefit, as thesecan be refined preoperatively to reducecomponent misalignment andligament misbalance.


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Our Solution

For all spinal construct testing, Ultra HighMolecular Weight Polyethylene (UHMWPE)blocks are used rather than vertebrae toeliminate the variances that bone propertiesand geometry may introduce.

Instron's universal test systems are idealfor static tensile and compressive tests.Static software test packages recordload displacement curves and performcalculations required by the ASTM standard.

For application of torsional strain any ofInstron's torsion tabletop test systems areideal. The 55MT MicroTorsion system can beused when multiple revolutions are required.The 8842 torsional DynaMight is a versatilesystem capable of 135 rotation. The systemalso offers the flexibility to handle both axialand torsional fatigue testing, in eitherhorizontal or vertical configurations.

Spinal Constructs

The Challenge

During normal patient activity, spinalconstructs can be subjected to high in

vivo loading, which may result in

catastrophic failure. Simple static

testing must be performed to evaluate

the compressive, tensile and torsional

loading required to fracture the

spinal construct.

Service life testing of spinal constructs is

critical as fatigue failure is more

common than catastrophic failure.

Loading is typically applied with a

constant-amplitude load-controlled

sinusoidal waveform, running in excess

of five million cycles.

ASTM F 1717 'Standard Test Methods

for Spinal Implant Constructs in a

Vertebrectomy Model' specifies methods

for both the static and fatigue testing of

spinal implant assemblies.

d

A universal test system determines the

compressive load to failure of a spinal instrument.

Both the video and clip-on extensometers monitor

local displacement of the spine specimen.

A DynaMight system determines the fatiguecapabilities of a spinal construct.

(Photo courtesy of Empirical Testing Corporation

and Spinal Concepts)

d

55MT MicroTorsion system for applying torsional strain to spinal implant constructs

Instron's 8870 and 8840 tabletop fatiguesystems achieve exceptional response andaccuracy across the frequency range and areideal for durability testing of spinal constructs.Control features, such as adaptive control andinertial compensation using Dynacell,

optimize system response, waveform fidelityand resolution.

d


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Our Solution

The BioPuls multiaxis modular spine testsystem allows load application in up tosix axes, supporting mechanical testingof spinal column sections includingoccipital/ cervical, cervical, thoracic andlumbar/ sacral. Building on the provenfoundations of the SMART spine tester, jointlydeveloped between Instron and the NationalUniversity of Singapore, the latest Instrondevelopment provides improved simulationof spinal kinematics.

Using successful clinical models, such asthose developed by White and Panjabi, theInstron system follows the free-end approachto spine testing. This approach results inmore physiological movement of eachvertebra with respect to one another, witheach axis of motion independently controlledand measured.

The multiaxial spine testing work head can beadded to an 8800 series fatigue test system.This is a cost-effective alternative to

purchasing a dedicated spine system. Thesystem also relies on use of multiaxial loadcells to fully characterize the loads induced inthe specimen. The 8800 controller providesthe exceptional control accuracy required formulti-axis testing. MAX software providespower and flexibility, including generation ofcomplex command waveforms andoptimization of data acquisition and storage.

Spine Simulation

The Challenge

The spine is the most complexmechanical system in the human body,

capable of six degrees-of-freedom

motion. Coupled motions have a

significant effect on a construct or disc

implant that cannot be predicted with

simple uniaxial testing. Multiaxial

testing helps further the understanding

of spine kinematics, aiding in the

design of new instruments and implants

that allow a more physiological range

of motion.

d

Instron's second generation BioPuls six axis

modular spine system


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Our Solution

A multistation system allows the testing ofmultiple specimens simultaneously to generatecomparative data. The BioPuls multistationIVD and prosthesis test system provides up tofour degrees-of-freedom motion, for coupledlateral and flexion-extension movements.The load frame accommodates up to five teststations and a soak control station. Eachstation can be operated and controlledindependently, and each is isolated from theothers to prevent cross contamination.

The testing software generates dynamicloading profiles to simulate physiologicalloading of the disc. The 8800 controllerensures sharp response to commandwaveforms, regardless of how many axes orstations are used. The test ends whenspecimens have been subjected to a specifiednumber of load profile cycles or when a discexperiences a failure such as a fatigue crack,substantial material loss or separation fromthe vertebrae.

Intervertebral Disc Prostheses

The Challenge

Intervertebral Disc (IVD) prostheses areused to replace damaged intervertebral

discs. There are two main types of IVDs:

articulating and load-resistant.

For load-resistant designs in particular,

cyclic loading may result in wear and

cause a decrease in disc height over

time. Wear testing typically requires

completion of millions of cycles, at a

frequency at or below 2 Hz to prevent

specimen heating and thus inaccurate

results. This many loading cycles at

relatively low speed takes weeks, even

months, of continuous run time

to complete.

ASTM and ISO standards for wear

testing of all types of IVD prostheses

are under development and will

require multiaxial simulation of

wear kinematics.

d

A compressive axial preload is applied to an

IVD, in conjunction with a cyclic torsion load

d

BioPuls multistation IVD prothesis test system


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Our Solution

An Instron fatigue testing system allowsresearchers and manufacturers to determinethe visco-elastic behavior of different areas ofthe sole. Fatigue loading tests are used toinvestigate parameters like energy absorptionand dynamic stiffness when performingactivities such as running and jumping.

Advanced features of our systems includeinertial compensation with Dynacell,trimodal control, and adaptive control

(where the control-loop terms adapt asspecimen stiffness changes). WaveMaker

software can run complex loading profiles,such as a starting ramp to a certain load, arunning cycle and a step-response(simulating a jump or a sudden impact).

Athletic Footwear

The Challenge

A person walking will experience loadsof up to three times their body weight at

the heels and up to eight times body

weight when exercising. Sports

footwear seeks to absorb some of this

impact loading and prevent it from

being transmitted to the body.

Different parts of the sole are tailored to

have different properties. The heels of

sport shoes are designed to absorb heel

impact energy, while the forefoot area

can enhance an athlete's performance

during push-off by acting like a spring

rather than dissipating the energy.

Determining the dynamic properties

and performance of these complex

visco-elastic materials in the sole is vital

to producing optimal footwear design.

d

The energy absorption and dynamic properties of a

running shoe are characterized using an 8800 system.

Our Solution

Impact testing is the most common methodfor evaluating the effectiveness of differentbarrier and cushioning materials used in themanufacture of helmets. The Dynatup

9250HV drop tower is a versatile instrumentwith a spring-assisted velocity accelerator forimpact velocities up to 20 meters per secondand impact energies up to 1,670 Joules to

accommodate a variety of different impacttesting methodologies.

For testing of the strap material, an Instronuniversal testing system may be used withscrew action grips, elastomeric roller gripsor the preferred pneumatic side action grips,for basic tensile tests to evaluate load to breakand tensile strength. Impulse softwareallows the user to easily calculate otherresults such as stress at preset strain valuesor the elastic modulus.

Protective Headgear

The Challenge

In many sporting activities, such as

football, cycling, horseback riding and

skiing, a helmet is the only method of

protection from sudden impact to the

head resulting from a fall or collision.

The use of protective headgear and

helmets has been proven to prevent fatal

head injuries and reduce the severity of

non-fatal head injuries in comparison to

incidents where helmets were not worn.

In order for these protective devices to

function properly, a variety of different

tests must be performed to ensure their

effectiveness. Such testing must

determine the impact strength of the

outer shell and the inner cushioning of

the helmet and the strength of the

strapping material.

d

A Dynatup impact test system is used to

determine the impact resistance of a football

helmet in order to verify that the materials and

design are sufficient for use on the playing field.


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Our Solution

Instron's MicroTester system offers theprecision necessary for low-force testing oftissues and biomaterials in tension,compression, flexure and fatigue. With thecorrect selection of a load cell and lightweightgrips, the system has an exceptional capabilityto run very low force tests. A digital encodermounted directly to the loading actuatorprovides accuracy and resolution surpassingthat possible with a standard lineardisplacement transducer. The MicroTester

also provides a much higher resolution thantraditional test systems for measuringextremely low loads, often in the subgramrange. The four-term 5800 closed-loopcontroller further enables accurate loadmeasurement and test control.

Tissues: Low Force

The Challenge

Many soft tissues, such as skin orcollagen, are delicate specimens with

low ultimate strength values. A test

system should be highly sensitive to low

force measurements and small

displacements in tension, compression,

flexure and fatigue. The in vivo

conditions must also be preserved, to

ensure that the mechanical properties of

natural tissues are maintained and that

bio-engineered tissues are tested in

their working environment.

The system features a two column design witha servoelectric actuator that minimizes noisein the test results without the need forhydraulic oil or compressed air, making itsuitable for clean room environments.The MicroTester can be configured verticallyor horizontally to fit on any laboratoryworkbench and for easy mounting of atemperature-controlled environmental bath

and optical instruments.

MicroTester in horizontal configuration using flat submersible grips in an environmental bath

d

25 N fatigue rated submersible flat grips

d

Micro three-point bend fixture with saline tank

d

Instron's MicroTester is extremely versatile for a

variety of low force tissue tests in both vertical

and horizontal configurations

d


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20 dBioPuls dual skin bath with the screw action grips

on an DynaMightTM

machine for tension-tension

fatigue of tendons

dEsophagus sample in BioPuls versa-grips for in vitro

tensile testing

d

Esophagus ends wrapped in paper to aid in gripping

d

BioPuls submersible versagrips in a single skin bath

are ideal for gripping higher-strength ligaments and

tendons and testing to failure

Our Solution

Within the BioPuls range there is a widechoice of high and low-capacity fixtures andenvironmental baths for tensile and fatiguetesting of a variety of tissues. These solutionsoperate with any Instron test system thatprovides advanced electronics for precision,reliability and control.

Alignment is less of a concern with soft tissuesthan with harder materials, but the problemsof gripping are much more severe. The

gripping solution is often specific to thecharacteristics of the specimen material andthe conditions of the test. The wide variety ofBioPuls options include line contact jaw faces,roughened grip surfaces, interlocking waveprofile faces, adhesively bonding of thespecimen ends, staples or stitched ends,through to freezer or cryogenic grips.

Soft Tissues: Uniaxial

The Challenge

Testing of human tissues such asligaments, tendons, the spinal cord and

the esophagus is essential to the

characterization of their behavior in

vivo. Testing is performed to determine

material properties used to set design

specifications for bio-engineered

replacement tissues and determine

expected values in surgical simulation

and modeling tools. In order to

accurately replicate tissue behavior

during testing, it is essential that the

physiological conditions are maintained.

Non-contacting strain measurementtechniques are often preferred to eliminateproblems associated with local stressconcentrations and deformation at thecontacting points. A video extensometer isparticularly suitable and can be used to offerhigh accuracy strain measurement, even withspecimens tested in environmental baths.


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Our Solution

The BioPuls low-force planar-biaxial softtissue system was developed to performmechanical testing and property analysis ofsoft planar biomaterials, native tissues andtissue-engineered scaffolds.

The configurable system consists of fourfatigue-rated actuators mounted to anair-suspended isolation table. The systemis capable of running both uniaxial andbiaxial tests to offer ultimate flexibility for

soft tissue testing.

The 8800 controller is capable of providingtrue planar-biaxial control, giving bothtranslation and deformation control in bothaxes. This aids in the ability for highlyaccurate specimen center-point control,allowing the use of optical instrumentsmounted above the specimen. Such

The Challenge

Planar biaxial testing of soft tissues isoften required to fully characterize the

inherent anisotropic properties of the

tissue or to set-up biaxial stress-strain

states to provide more accurate in vivo

simulation. With uniaxial testing, fibers

may realign along the test axis, altering

the mechanical properties of the tissue.

In addition, constitutive models cannot

be developed based on uniaxial

testing alone.

The gripping technique must be

capable of securely holding soft tissues

without causing damage, and lateral

deformations must be unrestricted in

order to ensure homogeneous specimen

deformation in the gauge area under

biaxial loading. In addition to this,

strain measurement must not damage

the tissue or cause stress concentrations

and be able to account for strain in all

directions of loading.

instrumentation includes non-contactingvideo extensometry for precise measurementsof strain in two dimensions or microscopesystems for structural observations. Theexceptional resolution of the controllerensures accuracy when measuring theextremely low loads associated with manysoft tissues.

A simple gripping method based on suturesand pulleys distributes the loading forces

equally around the specimen, allowingsimultaneous testing along the x and y axes.The entire system is easily configured with ourBioPuls temperature-controlledenvironmental baths, for simulation ofphysiological conditions during testing.

dTissue sample with suture grips and unique

non-contacting biaxial strain measurement system

BioPuls planar-biaxial system for soft tissue testing

Soft Tissues: Biaxial

d


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Our Solution

Instron's test systems provide the ability toperform variable speed tensile, compressive,indentation, flexure and fatigue testing on avariety of different bone specimens, fromsmall sections to intact long bones. Withdiversity in specimen size and geometry, theBioPuls fixturing is often unique to theobjective of the test. BioPuls offers a full lineof test fixtures including potting, tensile, bendand indentation fixtures and compressionplatens for testing of any bone specimen type.

Bone

The Challenge

Understanding the mechanicalproperties and behavior of bone helps

researchers develop replacement

materials and for regenerative solutions

to treat problems such as osteoporosis.

Test data on the mechanical behavior of

bone under combined loading patterns

experienced in vivo also helps

researchers create accurate models for

purposes such as predicting fracture in

patients and evaluating fracture

treatment protocols.

Bone is a naturally anisotropic material,

exhibiting different mechanical

properties in different directions. The

composition and loading response of

hard cortical and spongy cancellous

bone differ greatly and therefore require

a variety of testing solutions to accurately

characterize the tissue in vivo.

There are several items of interest where

testing bone is concerned: the fractureline will differ depending on the type and

combination of forces applied; the rate of

loading; and the moisture content, all of

which influence the mechanical

properties of bone.

d

Fixture applies shear loading to the femoral head of a rat femur

d

Compression test on a wet bone sample with

external strain measurement between platens

Strain measurement is also dependent uponspecimen size and geometry. For flat orround bone specimens, a clip-onextensometer may be mounted directly.For small, delicate specimens or those withirregular geometry, an LVDT may bemounted to the test fixtures. In some cases,a non-contacting video extensometer mayalso be an appropriate option.

An environmental bath is easily adapted to

any of the test systems and is used to ensurethat both hard cortical bone and softcancellous bone remain moist to provideresults indicative of the bone's behavior in thehuman body.

Software allows for versatility and simplemodification of the loading sequences toaccurately simulate loading in vivo. Inaddition, calculations such as elastic modulus,tensile strength and percent strain are simpleto set up and modify before or even after thetests have been conducted.

A DynaMight TM test system performs fatigue testing

on a whole bone

d


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23

Our Solution

The BioPuls solution for testing nitinol wireconforms to standard ASTM F 2063, StandardSpecification for Wrought Nickel-TitaniumShape Memory Alloys for Medical Devices andSurgical Implants. Pneumatic cord and yarngrips are most effective in obtainingmaximum stress at failure by reducing thestress concentration on the specimen at thegrip faces and by allowing easy loading andalignment of the specimen. This approachalso prevents wear of grip faces due to the

hardness of the material.

The non-contacting video extensometer allowshighly accurate strain measurement, whileeliminating failures associated with clip-onextensometers. Markers on the wire allow thevideo extensometer to track the relativeposition of markers throughout the test.

Nickel Titanium (Nitinol)

The Challenge

The shape memory and superelasticcharacteristics of nitinol make it an

extremely desirable material for many

medical devices. These include devices

such as stents, dental wires, internal

fracture fixation devices, catheter guide

wires and pins and biopsy forceps.

Nitinol wire is thin yet very hard and

causes numerous problems with

gripping. Unless the correct gripping

technique is used, failure of the wire

often occurs within the jaw face. When

measuring strain, the test system's

position transducer is often insufficient

to obtain accurate measurements.

Further, contacting extensometry may

introduce errors such as those caused by

the slippage of knife-edges or local

deformation at the contact point.

d

1 kN BioPuls pneumatic cord and yarn grips and

the video extensometer are successfully able to

test the ultimate strength of nitinol wire without

premature failure of the specimen as a result of

gripping or measuring strain.

Our Solution

Instron's 8800 fatigue systems are ideal fordurability testing of artificial heart valves andthe materials used in their production. Thesystems are capable of running dynamic testsacross a wide frequency range of manyelastomeric materials. A low force Dynacell

combined with lightweight grips is used tominimize inertial errors in the load readingand achieve exceptional control accuracy.An environmental bath provides in vivosimulation and determines how biologicalreactions to the elastomeric materialwill affect valve stability and life performance.

dAn 8872 system with wave profile grips for

fatigue testing of viscoelastic thin films

down to loads less than 10 N in solution

Replacement Materials

The Challenge

Heart valves are a very dynamic

component of the human body, opening

and closing with every heartbeat.

Elastomeric compounds are often anideal choice as a constituent material in

the manufacture of artificial valves as

well as replacement tissues, as they can

offer excellent durability and

long-term reliability.


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Our Solution

With a wide variety of needles available,

fixturing is unique to the objective and

application of the tests and results.

Test configurations such as the BioPuls

multineedle test fixture reduce testing time

in needle production and quality control

processes. Instron also offers a robust

single needle fixture that provides significant

advantages for research and development.

24

Regulatory agencies worldwide have set stringent

performance standards for nearly every category of medical

device. Today, bringing a new medical device to market

requires in-depth knowledge of all of its characteristics, from

properties of the raw materials to long-term performance

under complex service conditions. The testing required tomeet the wide variety of standards spans nearly every type of

mechanical test, including tension, compression, impact,

fatigue and hardness. For single-use products, testing is

particularly important during material selection to maximize

the trade-off between performance and cost. For implantable

devices, testing protocols ensure that the materials and

design will stand up to prolonged use in vivo.

This section provides a glimpse into some of the application

solutions Instron has provided to its medical device

customers. You will see how our engineers have addressed a

variety of applications, from standard items such as glovesand bandages to specialized products such as laparoscopy

instruments and orthopaedic fixation devices.

Needle Insertion Force

The ChallengeNeedle insertion force measurement is a

critical parameter for needle developers

as well as in quality control to ensure

patient safety. In recent years,

researchers and manufacturers have

invested significant resources in

developing surgical simulation and

preoperative planning tools, which

require parameters such as needle

insertion force. Insertion force is also

a key value in characterizing needle

geometry and sharpness, and in

understanding the effects of velocity,

viscosity and frictional force along the

needle axis during insertion into

soft tissues.

dThe BioPuls multineedle test fixture (upper)

and rotational membrane holder (lower)

increase the rate of testing on up to eight

needles at multiple penetration points

d

The BioPuls curved needle tester is used to ensure

that the needle is sharp enough to puncture tissue

and strong enough to retain its shape during use

d

A single straight needle fixture (upper) and variable

angle membrane holder (lower) are often used in

research and development processes for

characterizing needle sharpness


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Plunger Force for Needles and Syringes

Our Solution

Fixturing specific to the nature and

application of the test is usually required.

The lower grip is typically designed to hold

the barrel, and an upper unit is designed to

either eject liquid from the barrel in a

compression test or inspire liquid into the

barrel in a tensile test.

The Challenge

Needles and syringes must be tested to

ensure that the forces necessary to move

the plunger and eject fluid from the

barrel are not too high or too low.

These forces depend on many factors

including the device materials, viscosity

of the liquid, radiation processes used

for sterilization and instrument design.

When testing needles, the host tissue

into which the fluid is injected is

another factor influencing

device performance.

d

dd

A horizontal 5544 universal testing system with fixturing is used to

compare the effect of various medication viscosities on the breakout

and sustaining forces required to eject liquid from the barrel

The In-SpecTM 2200 or a 5544 universal testing

system with standard compression platens can

be used to evaluate breakout and sustaining

forces required to move the needle plunger

Instron universal testing systems can be

configured in either an upright or horizontal

position to utilize these fixturing options. In

some cases, the horizontal configuration is

advantageous because it allows accurate

simulation of the instrument in its functional

position. This configuration may also prevent

any sediment in the liquid from clogging the

barrel or needle tip during the test.


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Stents

The Challenge

Stents are used to support the arterial

walls after angioplasty. Typically, a stent

remains in the artery permanently,

improving blood flow to the heart.

Stent manufacturers need to measure

tensile strength and tensile strain of the

material to learn how much force the

wire can withstand and how much it

can stretch. Too little strain and the

stent will not be sufficiently flexible; too

much strain and it will not maintain its

functional shape.

d

A 5569 universal testing system with 1 kN

pneumatic side action grips with serrated faces

and video extensometer is used for testing

stent material in tension with high precision

strain measurement

dA close-up of the wire specimen loaded in the

pneumatic grips and marked with a 25.4 mm (1 in)

gauge length for measuring of strain with the

video extensometer

Bandages

The Challenge

Bandages are a commonly used

product whose materials and designs

are characterized by their ability to

carry a tensile load - i.e., how much

force they can withstand before failure

occurs in tension. Measurement of

mechanical properties allows

evaluation of bandage performance

while providing insight for

manufacturing processes and

quality control.

Our Solution

The primary objective for characterizing stent

material is determining tensile strength and

strain at break. For accurate strain

measurement, a non-contacting video

extensometer is preferred and is the only

feasible choice when wire samples will not

support the weight of conventional strain

devices. The video extensometer also prevents

premature failure of the wire associated with

the knife-edges of clip-on extensometers.

Pneumatic side action grips or screw grips

with serrated faces are proven the BioPuls

solutions for gripping this material.

Combined with software, this test

configuration allows the user to generate

stress-strain curves and report a variety

of results.

Our Solution

A standard tensile test is used to evaluate

tensile strength and elongation at break, twoimportant parameters in product development

and quality control. However, special

consideration must be given to testing these

materials without causing unwanted failures.

BioPuls elastomeric grips and pneumatic

grips are suitable for testing multistranded

woven materials used in bandages without

causing premature failure at the jaw faces.

Non-contacting strain measurement is

required where highly accurate measures of

strain are necessary. Our video extensometerenables precise measures of elongation

without damaging the material under test.

d

Elastomeric grips are used to evaluate the strength

of bandages in tension


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Sutures

Our Solution

Typical tests include a 'straight-pull' test,

which evaluates the tensile strength and

elongation of the suture material itself, and a

'knot-pull' test, which evaluates the tensile

strength of specific knotting techniques used

during surgery. Tests can be conducted in a

saline bath to evaluate the strength of suture

material under physiological conditions. The

fluid environment and body temperature can

change material properties, and such changes

must be understood before the materials areused in surgery.

The BioPuls pneumatically activated cord

and yarn grips, as well as manual capstan

grips, are ideal for gripping suture material.

Wrapping the material around the mandrel

ahead of the clamp eliminates high stress

points that lead to premature failure. Typical

test set-ups use a universal testing system.

For on-site and quality control testing, the

In-Spec 2200 portable handheld and

benchtop testers, combine low cost, and

portability with the precision required forlow-force suture testing and a PDA-based

data acquisition system.

The Challenge

Sutures are manufactured from a variety

of absorbable and non-absorbable

materials, and may be a single filament

or braided with or without coating.

Tensile strength and strain are critical

measures of performance during and

after surgical procedures. The strength

of different knotting techniques must

also be evaluated. The test method must

determine breaking strength and

corresponding percent elongation,

accurately measure strain withoutdamaging material and adhere to

Food and Drug Administration

(FDA) guidelines.

d

A 3345 universal testing system, configured with

pneumatic cord and yarn grips, is used to perform a

knot-pull test on suture material.

d

The In-Spec 2200 benchtop testing system is capable

of accurately and reliably evaluating the tensilestrength of sutures in the laboratory, on the

production line or in the field.

dClose-up of suture grips


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Our Solution

Testing is normally divided into two stages.

The first stage involves manual simulation

of the device using a

measurement and monitoring

system; the second is

designed to reproduce thesimulation in a test

machine. The

DynaMight testing

system supports

both configurations.

28

Our Solution

BioPuls pneumatic grips are ideal for

gripping delicate materials without tearing

or causing slippage. The grips allow for

adjustable gripping pressure and a choice of

face dimensions and surfaces, such as

rubber-coated, serrated, wave-profile or

flat metallic. Instron's high resolution,

non-contacting video extensometer provides

accurate strain measurement without

damaging the specimen. By attaching two

small markers to the sample, the video

extensometer precisely measures elongation

without extraneous loads or knife-edges to

distort the results. The video extensometer

and pneumatic grips are readily adapted to

any of Instron's universal testing systems,

which are engineered for precise control

and accurate alignment.

Medical Gloves

d

A 5544 universal testing system configured with

side action screw grips and rubber-coated faces

can be used for evaluating the tensile strength of

medical gloves

dThe DynaMight testing system configured withBioPuls fixturing is used to accurately simulate

grasping and twisting motions and perform

fatigue testing of a laparoscopic device

The Challenge

Medical gloves can be manufactured

from materials, such as latex, nitrile

and vinyl, all of which must adhere

to performance levels specified

by the FDA as well as international

standards (ASTM D 6319-00ae3,

ASTM D 5250-00e4, EN 455-2,

ISO 11193-1, ISO/AWI 11193-2).

The aging effects of the material

must be evaluated to ensure that

cross-contamination of the examiner

and the patient does not occur. Testingshould examine the strength and

elongation of the material at break to

ensure that measured values fall within

normal ranges of use. The main testing

difficulty usually involves measuring

strain, since traditional strain

measurement devices risk damaging the

material and causing unwanted failures

at the attachment points.

Laparoscopic Instruments

The Challenge

Laparoscopic surgery requires that

small and intricate mechanical devices

deliver large cutting or clamping forces

in a part of the body that would

otherwise be inaccessible to the

surgeon. Failure of such a device can

cause serious complications duringsurgery. Therefore, a series of static,

dynamic and simulation tests are

necessary to ensure durability, reliability

and integrity of a given design.

Evaluation includes measurement of

potentially harmful loads (through

squeezing and twisting) and

reproduction of these loads under

controlled conditions.

In the first stage of testing, strain gauges are

attached to the device at two locations to

accurately record loads during grasping and

twisting motions. Grasping and twisting

strains are continuously recorded during

aggressive use of the instrument. Peak valuesare used to set limits that the device is expected

to endure.

In the second stage of testing, which is based

on data from the manual simulation, two sets

of fatigue tests are developed. The first set

recreates and simulates grasping fatigue

(using an axial fatigue test system); the

second recreates and simulates twisting

fatigue (using a torsional fatigue test system).


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Our Solution

Testing is based on standard ASTM F 382,

Standard Specification and Test Method for

Metallic Bone Plates. The BioPuls test

fixture accurately replicates bending

movement during a single cycle test as well

as fatigue evaluation of the plate material and

design. The four-point bending fixture is

comprised of two loading rollers near the

center of the loading fixture and two support

rollers at the ends of the fixture. Rollers are

available in various sizes to cater for different

size bone plates.

The fixture was designed for use with the 8870

series fatigue testing system, which is ideally

suited to both static and dynamic tests. The

set-up can also incorporate a deflectometry

system (both in and out of an environmental

bath) to measure central deflection of the

fixation device.

Plate Fixation Devices

The Challenge

Metallic bone plates are used during

orthopaedic reconstructive surgery to

provide alignment and fixation of two

or more bone segments. The strength

and stiffness of the plate must allow the

bone to heal properly while providing

structural support. Quantification of

bending characteristics, such as

bending strength and bending stiffness

can provide surgeons with insight into

plate performance, while allowing

researchers to compare plate materialsand designs. The fatigue life of the

device over a specific time period or

range of maximum loading must also

be determined.

d

Stainless steel BioPuls bend fixture used to evaluatebending moments and to run durability tests on an

8870 test system.

d

Plate and angled orthopaedic fixation devicesAngled Fixation Devices

Our Solution

Testing is based on standard ASTM F 384,

Standard Specifications and Test Methods for

Metallic Angled Orthopedic Fracture Fixation

Devices. For static testing, a ramped

compression load is applied until the fixation

device plastically deforms or a set deflection isreached. The objective is to determine the

static bending stiffness of the plate. Four-point

bending and fatigue testing, using an 8870

fatigue testing system, is also necessary to

accurately evaluate the fixation device. The

fixture is designed to work with or without a

saline bath and can be adapted to suit a variety

of specimen sizes and geometries.

The Challenge

Angled orthopaedic fixation devices are

used to treat fractures in the

metaphyseal areas of long bones.

Loading creates a compression-

bending load at the angled portion,

which must be evaluated for strength

and stiffness by researchers when

comparing materials and designs, and

also by the surgeon to predict

performance. Fatigue life over a

specific time or loading range must

also be determined. For these reasons,

the test fixture must simulate

compressive loads experienced by the

angled portion of the plate as a result

of body weight.

d

An 8870 fatigue testing system with a BioPuls

fixture for an angled orthopaedic fixation device


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Surgical Tubing, Fittings and Catheters

Our Solution

In all testing applications, whether evaluating

the mechanical properties of the tubing itself,

or assessing the strength of the connection

between the tubing and the fittings, correct

gripping of the tubing is essential to

obtaining accurate measurements. BioPuls

pneumatically activated cord and yarn grips

or manual capstan grips are designed to

securely grip surgical tubing while ensuring

that test specimens fall within the gauge area.

For modulus and yield calculations, a

non-contacting strain measurement device

is necessary to accurately measure elongation

and prevent failures due to knife-edges or

clip-on extensometers. Our video

extensometer enables precise strain

measurement without damaging the tubing.

Instrons universal testing systems are ideal

for these testing requirements. For more

advanced applications, such as evaluating the

frictional force of surgical tubing in tortuosity

tests, a horizontal test configuration may be

necessary. Using the horizontal test frame,

tubing developers and quality control

specialists can design their own test method

for measuring various frictional, insertion and

removal forces of all types of tubing. For both

the upright and horizontal test frames, anenvironmental bath can easily be added to

the test space to ensure measurements are

taken under physiological conditions.

The Challenge

Surgical tubing is used in a wide range

of applications, such as drains, feeding

tubes, irrigation and surgical

procedures, and comes in many shapes

and sizes with dozens of possible

interconnections and fittings. The

mechanical performance of these items

is critical, as failure could seriously

endanger patients. Testing

requirements include failure of the

material, failure at joints and

simulation of physiological parameters.In more advanced cases, tortuosity tests

may be used to evaluate frictional forces

experienced within catheters as they are

fed through arterial vessels.

d

A 5545 universal testing system configured with

side action screw grips and serrated faces is used

to compare the strength of a fitting with the

ultimate strength of the tubing material

d

The In-SpecTM 2200 portable testing system is

capable of accurately and reliably evaluating the

tensile properties of medical devices and

materials in the laboratory, on the production

line or in the field

d

Tensile strength, strain at break and elastic

modulus measurements are acquired for thin-wall

tubing specimens using a 3345 universal testing

system, pneumatic side action grips and a long

travel extensometer


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Our Solution

Instron's Tear, Peel, Friction (TPF) software

module contains preconfigured methods for

conducting three different peel tests: T-peel,

90 peel and 180 peel. Using a high data

acquisition rate to ensure the peel profile is

accurately characterized, the strength of the

adhesive bond can be evaluated using the

basic calculation of maximum force on an

absolute peak, or using more advanced

calculations such as the average of a specific

number of peaks, troughs or combination ofboth. Users have great flexibility in specifying

where measurement begins and ends,

enabling the software to calculate a broad

range of results.

Medical Packaging

The ChallengeThe medical device industry is moving

toward prepackaged disposable devices

such as surgical instruments and

syringes. The tensile strength of the

adhesives used for such packaging must

be assessed according to ASTM F 88 to

ensure sterilization of instruments

during shipment and during storage at

the customer site.

d

A 3342 universal testing system with 250 N capacity pneumatic side action grips and line contact faces isused to grip disposable syringe packaging in a T-peel test. Such tests allow quality personnel to investigate

the seal strength of their packaging methods and to ensure the sterility of the devices after delivery.

d

The In-Spec 2200 portable testing system is

capable of accurately and reliably evaluating seal

strength of various types of medical packaging in

the laboratory, on the production line or in the field.

Typical set-ups use Instron's universal testing

systems configured with BioPuls

pneumatically activated side action grips,

which together provide the precise control and

accurate alignment required. Another option

for on-site and quality control testing are the

In-Spec 2200 portable handheld and

benchtop testers, which offer low cost, light

weight, mobility and precision for low force

suture testing together with a PDA-based data

acquisition system.


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Our Solution

Breast implant testing is conducted to evaluate

the performance of the design or material of a

specific implant, and also for comparison with

others on the market. A compression-fatigue

test is used to evaluate the strength and life of

the implant over time. With the implant

mounted between compression platens, the

test system must allow for cyclic compression

of the implant for 2 million cycles at 200

cycles per minute. Instron's fatigue testing

systems provides excellent accuracy and

waveform fidelity when performing such

fatigue tests in either load or position control.

MAX software allows easy set-up of these

straightforward cyclic tests, with variable data

collection rates to optimize data storage and

ensure that important data from events such

as yield or failure is collected. Fatigue test

systems can be run at higher frequencies to

reduce test time without compromising the

integrity of the test.

An impact resistance test is performed to

ensure that the implant does not fail under

sudden force. This test involves dropping a

specified mass vertically onto the implant.

In order to accurately control velocity and

acceleration of the mass, as well as collect

maximum impact load and deformation

values, a Dynatup drop tower is highly

recommended. The 9250HV with Impulse

machine control and data acquisition system

accurately delivers a repeatable impact to thespecimen while collecting load, time and

energy data.

Tensile tests are commonly performed on the

shell material to evaluate maximum strain

and integrity of the joints. Gripping the

material and accurate strain measurement

are key factors in the test configuration.

Instron's universal testing system together

with pneumatic side action grips and a video

extensometer accurately measures strain to

ensure that the material does fail prematurely.

Breast Implants

The Challenge

Breast augmentation and reconstruction

are common operations for women who

have suffered a mastectomy or for

cosmetic purposes. Implants are

manufactured with an outer shell,

usually made of an elastomer like

silicone, and filled with either silicone

or saline. The shape and size of implant

designs vary to accommodate patient

preferences. The mechanical

characteristics of these devices must be

evaluated, following standardsEN 12180 and ISO 14607, to ensure

patient safety over time.

d

An 8872 fatigue testing system with compression platens evaluates the fatigue properties of a breast implant

dThe Dynatup 9250HV drop tower is used to

evaluate the strength of the implant under impact


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The Challenge

A variety of testing applications are

related to blades and protective covers

to ensure safety to both users and

patients. The fitting of protective

covers must be assessed to ensure that

sterilization is preserved and the user

protected. For retractable blades, the

opening and closing forces must be

characterized. Similarly, tools with

removable blades must be

characterized to ensure that the forces

required to attach the blade are withinfunctional ranges, and the tool's

gripping mechanism is strong enough

to ensure that the blade will not be

removed during use.

Blades and Protective Covers

Our Solution

Due to the various shapes and sizes of these

tools, application specific fixtures or the

BioPuls pneumatic side action grips are ideal

for many applications. The pressure gauges

can be adjusted to carefully grip the device

without damaging the underlying instrument,

while providing enough pressure to prevent

slipping. In each case, the test set-up involves

loading the device into the fixture and running

the test at a speed that mimics actual use.

Using software, blade suppliers have fullcontrol over the testing process.

d

Tip pull off testing is performed with a BioPuls

upper fixture and a versa grip at the base of a

universal testing system

Disability Aids: Hip Protector

Our Solution

Evaluation of the performance of a hip

protector is conducted by simulating a fall

using an impact test system. By specifying

crosshead weight, drop height, velocity and

acceleration, test configurations can be

designed to accurately reproduce forces

produced during a fall.

The Dynatup 9250HV impact testing system

allows for all of these configurations, and the

Impulse machine control and data

acquisition system simplifies measurements

of maximum load, time to max load, time to

failure, total time, impact energy and energy

to max load. Results from such tests assist

researchers and engineers in the design of

protective devices, and help physicians

properly prescribe these devices to prevent

patient injury.

The Challenge

Accidental falls are a leading cause of

injury among elderly people.

Specifically, hip fractures are the largest

single injury resulting from falls in

patients aged 65 to 74 years.

Biomechanical analysis shows that the

maximum force on the hip when fallingapproaches three times body weight.

This can be reduced by about a third

using a protective device. The device

must be able to absorb and dissipate

impact energy and be comfortable

enough to wear on a daily basis.

d

The impact resistance of a hip protector is evaluated

using a Dynatup 9250HV impact test system


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Our Solution

The BioPuls test fixtures meet and exceed the

ISO requirements by addressing alignment of

the specimen during preparation as well as

preventing loss of alignment during testing.

The specimen preparation accessory follows

the ISO recommendations for set-up of the

specimen prior to test. It comes with a

complete set of tools including cups and studs

for multiple test specimens.

The tensile and shear adhesion test fixtures

are unique testing solutions with self-aligning

capability. The solution for tensile testing of

dental adhesion is an easy-to-use fixture

designed to correct angularity misalignments.The dental adhesion shear test fixture

incorporates frictionless bearings to minimize

measurement errors, and includes a range of

shear tools.

Tensile and Shear Adhesion

The Challenge

A key concern for dental restorative

materials and adhesives is their tensile

and shear bond strength to the tooth

enamel. However, alignment errors

associated with angularity and

concentricity of the specimen can make

pure tensile and shear testing difficult.

The ISO 11405 and ISO 7405 standards

seek to address this problem with

fixtures that ensure specimen alignment

during test set-up.

Understanding the mechanisms of everyday processes such

as eating and cleaning can help dentists and oral surgeons

find the optimal methods for maintaining healthy teeth.

Besides cosmetic considerations, dental restorations, such as

crowns, have to last and provide years of pain free and usefulservice. Evaluating the mechanical behavior of restorative

materials is important in establishing their function. Besides

the wear behavior of restorative materials, the durability of

the adhesives used in restorations is also vital to

implant longevity.

Instron's range of dental testing solutions encompasses these

wide variety of challenges.

d

BioPuls shear adhesion fixture

dSpecimen preparation accessory

d

Fixtures enable tensile adhesion strength of dental

materials to be evaluated


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Our Solution

The BioPuls micro three-point bend fixture

provides specialized features for testing

according to ISO 6872. The fixture addresses

the issues of alignment and parallelism that

are vital for these tests.

The fixture is engineered to ensure high

precision of span distances and centering.

The unit features and includes various sized

anvils with mounting in a V-slot for high

anvil parallelism.

Flexural Strength

The Challenge

ISO 6872 defines the basic requirements

for flexural testing of dental materials.

To accommodate the small specimen

size, a miniature bend fixture with the

ability to incorporate different anvil

diameters is required.

Our Solution

The BioPuls dental wear simulator is a

versatile and powerful tool for both

comparative wear studies and investigation of

wear mechanisms. The simulator is a dual

axis test system that works in mixed mode

control, allowing simulation of the

mastication cycle.

Loading during the gliding stage is achieved

by programming a load profile. As the molars

are in contact at this stage, it is vital for a

simulator to ensure that no impact or overload

occurs. Instron's advanced control systems

can detect and react within one millisecond to

prevent any overload.

Wear Testing

The Challenge

Wear is an important factor in the

longevity of dental restorative materials.

By simulating the mastication cycle, thewear performance and durability of

dental materials such as sealants and

amalgams can be assessed.

Research focuses on two main areas:

use of a standardized mastication

cycle to evaluate comparative wear

on a range of dental materials and

identification of different

wear mechanisms.

The key stages of simulated masticationare opening, crushing and gliding.

These stages require different control

methods - opening and crushing are

conducted in position control, while

gliding is performed in load control.

This control system, coupled with the

flexibility of the simulator design, opens a

range of testing opportunities for dental

researchers. Loading profiles can be varied to

simulate not just mastication but also bruxing

and clenching effects, enabling investigation

into a variety of wear mechanisms.

Multibody wear testing is also possible, as the

simulator allows abrasive food slurries to be

introduced into the test cell.

d

Micro three-point bend fixture for flexural tests

dAn 8872 system with BioPuls biaxial fixture

enabling mastication cycle to be simulated


36/40


37/40

37

Dynamic and FatigueTest Systems

Instron offers different types of servohydraulic

systems for a variety of applications and

laboratory environments. Single-column

models are cost-effective solutions for

biomaterials characterization and durability

testing of small components right on your

desktop while the table model systems aremore flexible for a variety of single and

multiaxial biomedical and component testing.

Systems are supplied as standard with the

patented Dynacell technology and

FastTrack 8800 controller, featuring benefits

such as adaptive control and choice of

user interface.

Impact Systems

Dynatup impact systems are designed to meet

very basic drop weight tests through to highly

sophisticated instrumented configurations and

offer low to high impact energy and velocity

capabilities that meet global standards.

The unmatched VHS series of high rate

systems use servohydraulic technologycombined with the advanced features of the

FastTrack 8800 controller to perform high

strain rate testing on a variety of biomaterials

and products.

Torsion Testers

Instrons line of torsion testers provides

dependable torsion and axial-torsion testing

capability. With a choice of electromechanical

or servohydraulic drive mechanisms and

Instroncontrol electronics, these torsion testers

are versatile and easy-to-use for many static

and dynamic biomedical applications.

d

The FastTrack 8870 series of dynamic systems

enables both static and dynamic testing of

biomaterials and medical products. The advanced

features of the FastTrack 8800 controller make it

an ideal testing platform for single-axis through to

complex multi-axis testing.

d

The VHS 20/ 20-25 system allows impact loads of

up 20 kN with speeds up to 25 m/s. With unique

control and data acquisition technology, a wide

range of grips and accessories is available to suit

differing application requirements.

d

The 55MT MicroTorsion system provides

continuous rotation testing of medical and

orthopaedic devices, where torsional forceswill help researchers and engineers understand

device performance.


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38

d

Instron's range of grips offers a solution for a wide

variance of specimens from thin fibers to metal

components, with load capacities starting at less

than 1 N. The grips pictured above are ideal

for elastomeric specimens, such as bandages or

latex gloves.

d

Special purpose fixtures, such as the four-point bend

fixture used here for flexion of titanium alloys often

used in fracture fixation devices, are available in a

variety of sizes and load capacities to accommodate

specimens of varying lengths and bend strengths.

d

Temperature controlled environmental chambers

are available in a range of sizes to accommodate

specimens from collagen to orthopaedic implants.

Many baths have a dual skin design to prevent

turbulence in the circulating fluid from affecting

the test results.

Instron offers an extensive selection of accessories,

including grips, fixtures, baths and software packages, that

are easily adapted to any test frame and are guaranteed to

fulfill almost any testing requirement. The range of BioPulsTM

accessories provides our customers with unmatched

versatility and flexibility in biomedical testing. In someinstances, our standard offerings do not accommodate the

variability of specimens or testing requirements. Through our

wealth of testing experience and engineering expertise, we

specialize in developing unique application-centric solutions

to meet these needs. Under the guidance of our Biomedical

Applications Team, we will ensure that all of your testing

requirements are met.


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39

Grips

g Lever action fiber grips

gScrew action grips

g Elastomeric grips

g Cord and yarn grips

g Wedge action grips

g Hydraulic grips

g Pneumatic grips

Special Purpose Fixtures

g Friction testing fixtures

g Peel testing fixtures

g Flexure fixtures

g Compression fixtures

g T-slot tables

d

Bluehill 2 software is a software package that offers the ultimate in

simplicity and power for biomedical testing. Its easy-to-use web-like

interface provides users with familiar features, such as cut and paste and

the ability to quickly and easily email reports. Furthermore, Bluehill 2 offers

unmatched flexibility in the configuration of methods, results and reports,

according to your preferences.

d

The Advanced Video Extensometer (AVE) offers high accuracy and resolution

in strain measurement. It is especially beneficial when the specimen under

test cannot support the weight of a traditional clip-on extensometer, as in the

case of soft tissues or nitinol.

Extensometry

g Video extensometer

gClip-on strain gauge extensometers

g Elastomeric long travel extensometers

g Linear Variable Displacement Transducers

(LVDT's)

g High Resolution Digital (HRD)

automatic extensometers

Baths and Chambers

g Temperature controlled and circulating

dual column baths

g High and low temperature

environmental chambers

g High and low temperature accessories

Software

g Bluehill

2- Fully integrated suite of

application modules for all types of

materials testing

g Series IX- Standard methods for

simple testing

g FastTrack Applications Suite - Advanced

fatigue and sequence loading applications

g Impulse - Data acquisition and

analysis system for impact testing

g Partner - Advanced software for static

and torsional testing requirements

g ComplianceBuilder - Software module

provides capabilities to comply with21 CFR 11


40/40

orporate Headquartersstron Corporation

25 University Avenue

orwood, MA 02062-2643 USA

el: +1 800 564 8378

+1 781 575 5000

ax: +1 781 575 5725

uropean Headquartersstron Limited

oronation Road

igh Wycombe, Bucks

P12 3SY United Kingdom

el: +44 1494 464646

ax: +44 1494 456814

ndustrial Products Group00 Liberty Street

rove City, PA 16127-9005 USA

el: +1 800 726 8378+1 724 458 9610

ax: +1 724 458 9614

ST GmbHandwehrstrasse 65

armstadt, D-64293 Germany

el: +49 6151 3917-0

ax: +49 6151 3917-500

For information on Instron products and services call your local worldwide sales, service and technical support offices:

USANorth America IMT Sales and Service Center

Sales Tel: +1 800 564 8378

Service and Technical Support Tel: +1 800 473 7838

North America IST Sales and Service Center

Sales and Service Tel: +1 248 553 4630

CANADAToronto Tel: +1 905 333 9123

+1 800 461 9123

SOUTH AMERICA, CENTRAL AMERICA,MEXICO AND CARIBBEANBrazil

Sao Paulo Tel: +55 11 4689 5480

Caribbean, Mexico, South America

and Central America

Canton Tel: +1 781 821 2770

EUROPEUnited Kingdom, Ireland,

Sweden, Norway and Finland

High Wycombe Tel: +44 1494 456815

Benelux and Denmark

Edegem Tel: +32 3 454 0304

France

Paris Tel: +33 1 39 30 66 30

Germany and Austria

Darmstadt Tel: +49 6151 3917 444

Italy

Milan Tel: +39 02 390 9101

Spain and Portugal

Barcelona Tel: +34 93 594 7560

ASIAChina

Beijing Tel: +86 10 6849 8102

Shanghai Tel: +86 21 6215 8568

India

Chennai Tel: +91 44 2 829 3888

Japan

Tokyo Tel: +81 44 853 8520

Osaka Tel: +81 6 6380 0306

Nagoya Tel: +81 52 201 4541

Korea

Seoul Tel: +82 2 552 2311/5

Singapore Tel: +65 6774 3188

Taiwan

Hsinchu Tel: +886 35 722 155/6

Thailand

Bangkok Tel: +66 2 513 8751/52

AUSTRALIAMelbourne Tel: +61 3 9720 3477

Documents

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