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Nitinol for Medical Devices - Grado Zero Espace Srl

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<strong>Nitinol</strong> <strong>for</strong> <strong>Medical</strong> <strong>Devices</strong><br />

Fundamentals of Shape Memory<br />

<strong>Nitinol</strong> Processing<br />

Design and Application<br />

Where is <strong>Nitinol</strong> Used?<br />

<strong>Medical</strong> Device Characteristics<br />

Design Case Studies<br />

Environmental Effects<br />

1


Applications of <strong>Nitinol</strong><br />

2


<strong>Nitinol</strong> History<br />

1970 First aircraft applications<br />

1975 Orthodontic arches — first superelastic application<br />

1980 Guidewires<br />

1985 Instrument components<br />

1990 Stents<br />

3


Where is <strong>Nitinol</strong> Used?<br />

Constrained Recovery<br />

4


Where is <strong>Nitinol</strong> Used?<br />

Actuators<br />

5


Where is <strong>Nitinol</strong> Used?<br />

Actuators<br />

<strong>Grado</strong> <strong>Zero</strong> <strong>Espace</strong> S.l.r.<br />

6


Where is <strong>Nitinol</strong> Used?<br />

Superelasticity<br />

7


Where is <strong>Nitinol</strong> Used?<br />

Thermal Actuation<br />

Dr. Charles Dotter<br />

9


Where is <strong>Nitinol</strong> Used?<br />

<strong>Medical</strong><br />

<strong>Devices</strong><br />

10


<strong>Nitinol</strong> <strong>Medical</strong> Device Characteristics<br />

Biomechanical<br />

Compatibility<br />

Elastic Deployment<br />

Thermal Deployment<br />

Kink Resistance<br />

Constancy of Stress<br />

Dynamic Interference<br />

Hysteresis / Biased Stiffness<br />

Fatigue Resistance<br />

Biocompatibility<br />

MR Compatibility<br />

11


MR Compatibility<br />

12


Guidewires<br />

Elastic Deployment<br />

Kink Resistance<br />

Fatigue Resistance<br />

Biocompatibility<br />

MR Compatibility<br />

SMA, Inc.<br />

13


Bone Reamers<br />

Kink Resistance<br />

Fatigue Resistance<br />

Biocompatibility<br />

MR Compatibility<br />

Zimmer<br />

14


Needle/Wire Localizer<br />

Elastic Deployment<br />

Kink Resistance<br />

Biocompatibility<br />

Homer Mammalok® (Mitek)<br />

15


RF Tissue Ablation<br />

Elastic Deployment<br />

Kink Resistance<br />

Fatigue Resistance<br />

Biocompatibility<br />

RITA <strong>Medical</strong> Systems, Inc.<br />

16


Baskets<br />

Elastic Deployment<br />

Kink Resistance<br />

Dynamic Interference<br />

Fatigue Resistance<br />

Biocompatibility<br />

MR Compatibility<br />

17


Organ Retrieval<br />

Elastic Deployment<br />

Kink Resistance<br />

Fatigue Resistance<br />

Biocompatibility<br />

MR Compatibility<br />

Covidien<br />

18


Snares<br />

Elastic Deployment<br />

Kink Resistance<br />

Dynamic Interference<br />

Fatigue Resistance<br />

Biocompatibility<br />

MR Compatibility<br />

ev3<br />

19


Embolic Protection <strong>Devices</strong><br />

BSC<br />

Abbott<br />

Elastic Deployment<br />

Kink Resistance<br />

Dynamic Interference<br />

Fatigue Resistance<br />

Biocompatibility<br />

MR Compatibility<br />

Cordis<br />

ev3<br />

20


Deflectable Instruments<br />

Endius Flextip<br />

Surgical Innovations<br />

Endius<br />

Elastic Deployment<br />

Kink Resistance<br />

Biocompatibility<br />

MRI Compatibility<br />

21


Flexible Micrograsper<br />

Bacher<br />

Elastic Deployment<br />

Kink Resistance<br />

Fatigue Resistance<br />

Biocompatibility<br />

MR Compatibility<br />

22


Heart Valve Sizer<br />

De<strong>for</strong>mable Martensite<br />

Fatigue Resistance<br />

Biocompatibility<br />

St. Jude<br />

23


Vascular Closure <strong>Devices</strong><br />

<strong>Nitinol</strong> Needles<br />

Perclose<br />

Elastic Deployment<br />

Kink Resistance<br />

Fatigue Resistance<br />

Biocompatibility<br />

Abbott<br />

24


Suture Anchor<br />

Biomechanical Compatibility<br />

Elastic Deployment<br />

Biocompatibility<br />

MR Compatibility<br />

Mitek 25


Bone Staples<br />

Biomechanical Compatibility<br />

Thermal Deployment<br />

Fatigue Resistance<br />

Biocompatibility<br />

MR Compatibility<br />

BME, Inc.<br />

26


Spinal Cage<br />

Depuy Spine<br />

Biomechanical Compatibility<br />

Elastic Deployment<br />

Biocompatibility<br />

MR Compatibility<br />

27


Septal Occlusion<br />

Biomechanical Compatibility<br />

Elastic Deployment<br />

Biocompatibility<br />

MR Compatibility<br />

AGA <strong>Medical</strong> W.L. Gore 28


Vena Cava Filters<br />

Cordis<br />

C.R. Bard<br />

29


Stents and Stent Grafts<br />

Stents use a wide range of properties<br />

Biomechanical Compatibility<br />

Elastic or Thermal Deployment<br />

Kink Resistance<br />

Constancy of Stress<br />

Dynamic Interference<br />

Hysteresis / Biased Stiffness (COF and Crush Resistance)<br />

Fatigue Resistance<br />

Biocompatibility<br />

MR Compatibility<br />

30


Neuro<br />

Carotid<br />

Esophagus<br />

Trachea<br />

Biliary<br />

Colon<br />

Urinary Tract<br />

“The human body is a<br />

series of tubes just waiting<br />

to be stented”<br />

Dr. Paul S. Teirstein, 1998<br />

Coronary<br />

Aorta<br />

Iliac<br />

Femoral<br />

Popliteal<br />

Non-Vascular<br />

Vascular<br />

31


<strong>Nitinol</strong> Self-Expanding Stents<br />

Coil Stents<br />

Woven Wire Stents<br />

“Wiggle Wire” Stents<br />

“Slotted Tube” Stents<br />

Abbott<br />

ev3<br />

BSC<br />

Medtronic<br />

32


Design: Case Studies of<br />

Engineering Challenges of Selected<br />

<strong>Nitinol</strong> <strong>Medical</strong> <strong>Devices</strong><br />

33


Case Study 1:<br />

Homer Mammalok<br />

A f = -10˚C, 14˚C, 27˚C<br />

Challenge: Determine the Effect of A f<br />

on Deployment Stress and Strain<br />

34


Effect of A f on Tensile Properties<br />

35


FEA of Hook Retraction<br />

36


FEA Strain Distribution<br />

δAf = TT - Af<br />

STRAIN<br />

37


FEA Stress Distribution<br />

δAf = TT - Af<br />

STRESS<br />

38


Case Study 2: Stents<br />

Challenges:<br />

Determine stresses and<br />

strains during loading<br />

and deployment<br />

Optimize in vivo <strong>for</strong>ces<br />

39


Loading into the Catheter<br />

41


Chronic Outward Force<br />

COF<br />

42


Radial Resistive Force (RRF)<br />

RRF<br />

43


Stress and Strain Analysis<br />

44


Stress - Strain Distribution<br />

45


Radial Force Testing<br />

Is there an ideal A f <strong>for</strong> a stent? What are the effects of A f ?<br />

46

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