Implantable devices take many forms from cardiovascular, endovascular, neurovascular stenting, and associated delivery systems to heart valves and pacemakers, through to auditory and ocular implants, such as intraocular or contact lenses. Many of these devices are wonderful creations of modern medical engineering that aid physicians, surgeons, and medical specialists in the treatment of various diseases and conditions.
With stringent requirements from regulations, manufacturers must demonstrate that they have considered risks of device failure and satisfactorily mitigated against them. Mechanical testing of implantable devices is performed in vitro to aide designers and researchers in gathering performance data ahead of device approval and clinical use. Although mechanical testing does not begin to simulate the complete in vivo conditions that devices undergo, it does allow experimental validation and provides more accurate data for Finite Element Analysis (FEA) and computer modelling of them to be undertaken.
Mechanical testing takes many forms, from testing of the constituent metals and alloys to compression and flexural testing of complete devices, through to dynamic simulation of pressure pulsation. Some examples of testing configurations are:
- Tensile Testing of Nitinol Wire to ASTM F2516
- Three-Point Bending of Balloon Expandable Vascular Stents and Stent Systems to ASTM F2606
- Stent Dislodgement Force from a Balloon Catheter
- Radial Force Evaluation of Stent Grafts
- Evaluation of Radial Forces from Embolic Filters
- Fatigue Testing of Stent Materials and Structures– An Alternative to ASTM F2477
- Compression Test on Intraocular Lenses
- Tensile Testing of Contact Lenses in a Temperature-Controlled Bath
Testing systems that can be used for implantable devices include the 3340 and 3360 Series, 5940 and 5960 Series, and the ElectroPuls™ dynamic test instruments. Other testing systems, such as torsion, multi-axial and impact, can also be used.