Medical Device Non-Clinical Bench (Mechanical) Testing

Based on the medical device class risk level, medical device manufacturers and developers in the United States must submit regulatory approval applications to the US Food and Drug Administration. This blog post covers non-clinical bench performance testing, specifically mechanical testing, and its reporting as recommended by the FDA, and provides a list of mechanical testing machines to run medical device testing.

The Food and Drug Administration (FDA) describes non-clinical bench performance testing as performance testing that encompasses all bend testing and is dependent upon the specifics of the actual medical device or device type. Non-clinical bench testing includes but is not limited to: mechanical tests to determine properties such as fatigue lifecycle, tensile strength, compression strength, puncture resistance, and flexural strength.

Per FDA guidance documents, non-clinical bench test information must be included in the premarket approval (PMA) applications, humanitarian device exemption (HDE) applications, premarket notification (510(k)) submissions, investigational device exemption (IDE) applications, and De Novo requests. Testing can be performed by the device manufacturer or an independent test lab. The tests selected should address the verification of the design inputs and ensure safety and efficacy.

What to include in Non-Clinical Bench Performance Testing Reports

FDA Guidance Document Recommended Content and Format of Non-Clinical Bench Performance Testing Information in Premarket Submissions includes detailed information on ways to facilitate FDA’s review when reporting non-clinical bench performance testing information. Depending on the type of device and type of application, test report summaries of the conducted testing as well as complete test reports should be included with the premarket submission. For example, complete test reports are typically not needed for Special 510(k) applications. For 510(k) applications with substantial equivalence, test reports should discuss and demonstrate how the newly designed device is substantially equivalent to the proposed primary predicate while for PMA applications, test results should ensure reasonable safety and effectiveness.

Test Report Summaries
1. Tests Performed
2. Objectives of the Tests
3. Brief Description of the Test Methods
  1. Description of the test sample (whether it is a final, finished device, whether it is a part or a component or the entire device, etc.
  2. Sample size
  3. How the samples represent a clinically relevant worst-case scenario
  4. Consensus standards followed
4. Pre-defined Pass/Fail Criteria
  1. Identification of the acceptance or assessment criteria
5. Results Summary
  1. For quantitative assessments: mean, standard deviation, minimum, and maximum for normal data, summary parameters
  2. For qualitative data: number of observed characteristics by category, confidence/reliability level
  3. Specify whether the acceptance criteria were met and provide explanations if not
6. Discussions & Conclusions
  1. Discussion of how the test results support the overall submission
  2. Justification for the methods used to perform the testing, clinical/scientific/engineering basis for the acceptance criteria, outlying and anomalous results
  3. Relationship between the results and the intended performance of the device
7. Location of the Complete Test Report
8. Summary Table (Optional)
  1. Test Performed
  2. Device Description
  3. Sample Size
  4. Test Method/Applicable Standards
  5. Acceptance Criteria
  6. Unexpected Results
  7. Results
Complete Test Reports
1. Test Performed
2. Objective of the Test
3. Description of Test Methods
  1. Test Sample Information
  2. Test Sample Size/Selection
  3. Test Methods
4. Pass/Fail Criteria
5. Data Analysis Plan
6. Test Results
  1. Data
  2. Data Analysis
  3. Protocol Deviations
7. Discussions & Conclusions
Test Protocols

Mechanical Testing Equipment for Medical Devices

Complete test reports submitted to the FDA include information on the equipment used during non-clinical bench testing of medical devices. These are often presented with labeled diagrams or photographs of the test setup and test fixtures. Over the years, ADMET has worked with many medical device manufacturers to develop testing solutions that will ensure their products meet the necessary specifications. Below is a selection of testing systems used in medical device testing.

Universal Testing Machines

eXpert 2600 dual column and eXpert 7600 single column testing machines are well suited for testing syringes, suture material, medical packaging and tubing, external fixating devices, medical adhesives, and more. Researchers have also used these systems to test biologic tissues and gels. Whether it is testing to an in-house, ASTM or ISO standard, ADMET offers a full line of grips, fixtures, fluid baths and environmental chambers to meet your needs.

Fatigue Testing Machines

eXpert 5900 electrodynamic and eXpert 1900 servohydraulic fatigue testing systems can perform multi-million-cycle tests at ASTM and ISO specified frequencies. These systems are used to evaluate the mechanical properties of biologic materials, prostheses, spinal constructs, stents, hip, shoulder, and dental implants, elastomeric materials, and more. A variety of grips and strain measuring devices are available for determining properties such as elastic modulus, tensile strength and elongation. In addition, heated fluid baths are offered to facilitate testing in vitro.

eXpert 1900 – Hip Implant Fatigue Testing

eXpert 1900 series and 5900 series machines are commonly employed to perform the following ASTM and ISO tests:

Axial-Torsion Testing Machines

eXpert 8600 axial-torsion testing systems are used to determine the mechanical properties of bone screws, medical implant and body fusion devices, luer lock/luer taper fittings, adhesives, and more. The eXpert 8600 features high axial and torsional rigidity and have oil-free linear and rotary actuators for clean room operation. They also feature unlimited torsion actuator rotation, wide column spacings, and large actuator strokes for maximum flexibility.

eXpert 8600 axial-torsion testing systems can be configured to run ASTM F543 Annexes A1 – A4.

eXpert 8602 – ASTM F543 Testing

Torsion Testing Machines

eXpert 9000 torsion testing machines are ideal for determining the torsional properties such as torsional yield strength and breaking angle of bone screws, spinal constructs, intramedullary rods, biomaterials used in fracture repair, wire used in dentistry, and more. eXpert 9000 torsion testing systems feature:

Horizontal and vertical orientations
Static and fatigue testing solutions
Unlimited rotation in both directions
Secondary load cell for measuring axial tension/compression forces
Displacement transducer for measuring axial movement of the drive spindle

eXpert 9000 Vertical for Orthopedic Torsion Testing

eXpert 9000 Vertical – Orthopedic Torsion Testing

Controller & Software

ADMET’s MTESTQuattro controller software helps to satisfy the requirements of FDA CFR 21 Part 11 by creating a documentation trail whenever there are changes to test procedures. These changes result in creation of a record which indicates what was changed, when, and by whom.

Furthermore, MTESTQuattro allows CFR 21 Part 11 administrators to limit the access users have within the program on an individual basis. This ensures that the manner in which tests are performed, i.e. test procedures, can only be modified by authorized persons.

Conclusion

Full test reports for all test performed should be included for regulatory approval of medical devices. Further details can be found on FDA’s Non-Clinical Bench Performance Testing Information Guidance Document. Mechanical testing should be performed by accurate universal testing systems equipped with controls and software producing repeatable and reliable results. Talk to an ADMET Sales Engineer to discuss medical device testing equipment and the best fit for your application.