Total intervertebral spine disc prostheses (artificial discs) are used as motion preserving replacements for patients with damaged or degenerated discs in the spine. The development of artificial discs comes with a number of challenges that must be accounted for. Not only do prosthetic discs need to allow for movement and provide stability, but they must also keep up with everyday life (activities of daily living or ADL). Motion preserving implants also must meet a higher bar of safety and efficacy than fusion systems since they are required to preserve the anatomical motion for as long as possible. This more rigorous testing regime requires a team that understands the design challenges, regulatory environment, and the required rigor in tackling a problem such as this.
The prosthetic’s long-term ability to function in the body and perform daily activities is the impetus of its clinical use, testing of artificial discs helps establish whether or not it will do so in a clinical environment. Before submitting a new device to the FDA for approval, establishing that it is capable of long-term use is essential. This pre-clinical process predicts mid- to long-term wear characteristics of these novel devices.
Testing standards for in-vitro wear of total intervertebral spine prosthetic devices have been issued by both the International Organization for Standardization (ISO Standard 18192-1) and the American Society for Testing and Materials (ASTM F2423). With the application of ISO Standard 18192-1, also known as the spinal disc wear test, the dynamic behavior of intervertebral spine disc prostheses is established before they are used in a clinical setting.
ISO 18192-1: Implants for Surgery
The International Organization for Standardization (ISO) is a global national standard coalition that issued Standard 18192-1, the spinal disc wear test, in 2008. With the application of ISO Standard 18192-1, the mid-range wear behavior of an artificial disc is evaluated. This critical pre-clinical process, along with characterization testing (F2346 (link)) is a critical part of a successful submission.
This test assesses lumbar and cervical prostheses, but it does not apply to partial disc replacements (e.g. facet joint replacements, nucleus replacements, annuls replacements and active ISS systems. ISO 18192 specifies the range of motion, loading criteria and phasing of the axes, lateral bend, flexion extension, rotation, and compression, that the artificial disc will be subjected to. This is a coupled motion test that using axis phasing to generate an ADL (Activities of Daily Living) approximation for the device. This test is also performed in Bovine Serum to better mimic the body’s physiological condition.
The test is conducted by four moving axes (Mx, My, Mz, and Z) in order to simulate the in-vivo conditions. ISO Standard 18192-1 tests are performed with deionized water and diluted newborn calf serum with a protein content of 20g/l. Generally, simultaneous testing is applied to six specimens and two soak controls. The specimens’ weight loss establishes the amount of wear according to ISO 14242-2. After 10 million cycles, the test is stopped.
Working with Empirical Technologies Corp.
When it comes to regulatory approval, the quality of testing makes a big difference. The caliber of talent conducting tests also influences the outcomes. Here at Empirical Technologies, we work with an exceptional and talented team that is dedicated to providing top-notch mechanical testing. We perform standard tests across the board, including ISO 18192-1 testing.
With a wealth of knowledge and over 20 years of experience in the industry, Empirical can work with you to mechanically test your medical devices. As an industry leader in the testing and submission of orthopedic prosthetics, Empirical Technologies has the expertise to help your device receive approval in the United States and on international markets.
Contact us today to request an estimate for ISO 18192-1 testing for your intervertebral spine disc prosthetic.
Please refer to the ISO website for the most up to date information on ISO 18192-1 or visit our Quality Standards page to see additional accredited test standards performed at our certified testing laboratory.