Overview - ISO 18192-3:2017 (Impingement-wear testing for lumbar disc prostheses)
ISO 18192-3:2017 specifies a laboratory test procedure and corresponding environmental conditions to simulate and evaluate impingement wear of lumbar total intervertebral spinal disc prostheses under adverse kinematic conditions. The standard focuses on reproducing clinically relevant impingement scenarios (extension, flexion, lateral bending, combined motions) to assess wear, damage and worst-case contact behavior of lumbar prostheses in a controlled, physiological-like environment.
Key topics and technical requirements
- Scope and principle
- Simulate repeated contact between design features using axial load and time-varying angular displacement.
- Consider extension (commonly reported), flexion, lateral bending and combined motions; axial rotation can be combined if needed to reproduce clinically relevant scars.
- Definitions
- Important terms: impingement, range of motion (ROM), distance between centre of rotation and point of impingement (DCI), and axial load during impingement (ALI).
- Test specimens and controls
- Recommended minimum: six specimens (or justified fewer); at least three per size when multiple sizes are tested.
- For polymer components, include a load soak control to measure creep and fluid uptake.
- Weighing precision: 0.1 mg for non-absorbing specimens.
- Fluid and environmental conditions
- Test medium: calf serum diluted with de‑ionized water to 20 g ± 2 g protein/l, prepared per ISO 18192-1.
- Temperature, lubrication and enclosure per ISO 18192-1.
- Apparatus and performance
- Test machine conforming to ISO 4965-1 and ISO 23788 with coordinate system aligned to device centre of rotation.
- Motion control: ±1° accuracy at motion extrema and ±5% cycle-time phasing.
- Force control: axial force tolerance ±5% of maximum and ±5% phasing.
- Test method details
- Develop load/displacement profiles prior to testing; ROM shall be exceeded by at least 2° in the impingement direction and the impingement region must be offloaded each cycle.
- Example: extension impingement using a 7.5 Nm moment; compute ALI by dividing the moment by DCI (in metres).
- Annexes
- Annex A: gravimetric wear measurement method (normative).
- Annex B: justification of the test method (informative).
Practical applications and users
- Who uses this standard:
- Spinal implant manufacturers (design validation, product development)
- Biomechanics and wear testing laboratories
- Regulatory bodies and notified bodies reviewing preclinical performance data
- R&D teams performing risk analysis and worst-case testing
- Typical applications:
- Preclinical wear and durability evaluation of lumbar disc replacements
- Comparative testing of materials and designs under adverse kinematics
- Supporting regulatory submissions and lifetime performance claims
Related standards
- ISO 18192-1 - Loading/displacement parameters and environmental conditions for wear testing (lumbar)
- ISO 4965-1 - Dynamic force calibration for uniaxial fatigue testing
- ISO 23788 - Verification of alignment of fatigue testing machines
Keywords: ISO 18192-3:2017, impingement-wear testing, lumbar spinal disc prostheses, wear testing, spinal implant testing, total intervertebral spinal disc prostheses.