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Lumbar Integrated Fixation Devices-Best Practices for Biomechanical Evaluation Under Fatigue Loading

Catalog of Regulatory Science Tools to Help Assess New Medical Devices 

 

This regulatory science tool presents a lab method for executing in vitro human cadaver fatigue loading and multidirectional flexibility assessment of lumbar integrated fixation device constructs. Please see appendix.  

 

Technical Description

This tool provides recommended best practices for performing in vitro human cadaver based biomechanical evaluation of lumbar integrated fixation devices (IFDs) under fatigue loading. This tool also describes recommendations for performing multidirectional flexibility assessment of IFD constructs in the intact state, before and after the fatigue loading, to quantify the effect of the IFD on segmental range of motion (ROM). The tool Appendix describes recommendations for:

  • Specimen preparation
  • Study design
  • Biomechanical testing
  • Data analysis

Intended Purpose

This tool may be helpful and applicable for medical device manufacturers in evaluating the long-term biomechanical stability of IFDs and evaluating the following post-operative risks:

  • Fracture of the IFD or fixation anchors/screws, or both
  • Migration of the IFD or fixation anchors/screws, or both
  • Damage to the vertebral body
  • Insufficient segmental stabilization

Testing

Use of this tool has been demonstrated in the following peer-reviewed publication for comparing long term biomechanical stability of a generic IFD (investigational implant) with a generic anterior plate and cage device (control implant):

Limitations

This tool provides best practices for the biomechanical evaluation of IFDs under fatigue loading along with multidirectional flexibility assessment of IFD constructs before and after fatigue loading. Extrapolation of this tool to other medical device types may not be appropriate. This tool may not replace the need for clinical data, animal testing, or other methods, as appropriate, and described in documents such as:

Supporting Documentation

This paper describes the recommended loading methods, specimen conditions, and analysis parameters for in vitro human cadaver biomechanical stability testing of spinal implants

The multidirectional flexbility loading protocol used for our validation study was based on the following papers:

Contact

Tool Reference

  • In addition to citing relevant publications please reference the use of this tool using RST24OP05.01