This part of ISO 18192 defines a test procedure for the relative angular movement between articulating components, and specifies the pattern of the applied force, speed and duration of testing, sample configuration and test environment for use for the wear testing of total intervertebral spinal disc prostheses. Both lumbar and cervical prostheses are addressed. This part of ISO 18192 is not applicabe to partial disc replacements, such as nucleus replacements or facet joint replacements. The test method focuses on wear testing. Additional mechanical tests, such as fatigue testing, can be required. This part of ISO 18192 does not reproduce the complex in vivo loads and motions. The wear data obtained with this test method enables comparison between different types of implants, but can differ from the clinical wear performance. The user of this part of ISO 18192 can consider running additional wear tests addressing specific safety issues of the individual implant design under test.