Significance and Use
Intervertebral body fusion devices are generally simple geometric shaped devices, which are often porous or hollow in nature. Their function is to support the anterior column of the spine to facilitate arthrodesis of the motion segment.
This test method is designed to quantify the subsidence characteristics of different designs of intervertebral body fusion devices since this is a potential clinical failure mode. These tests are conducted in vitro in order to simplify the comparison of simulated vertebral body subsidence induced by the intervertebral body fusion devices.
The static axial compressive loads that will be applied to the intervertebral body fusion devices and test blocks will differ from the complex loading seen in vivo, and therefore, the results from this test method may not be used to directly predict in vivo performance. The results, however, can be used to compare the varying degrees of subsidence between different intervertebral body fusion device designs for a given density of simulated bone.
The location within the simulated vertebral bodies and position of the intervertebral body fusion device with respect to the loading axis will be dependent upon the design and manufacturer's recommendation for implant placement.
1.1 This test method specifies the materials and methods for the axial compressive subsidence testing of non-biologic intervertebral body fusion devices, spinal implants designed to promote arthrodesis at a given spinal motion segment.
1.2 This test method is intended to provide a basis for the mechanical comparison among past, present, and future non-biologic intervertebral body fusion devices. This test method is intended to enable the user to mechanically compare intervertebral body fusion devices and does not purport to provide performance standards for intervertebral body fusion devices.
1.3 This test method describes a static test method by specifying a load type and a specific method of applying this load. This test method is designed to allow for the comparative evaluation of intervertebral body fusion devices.
1.4 Guidelines are established for measuring test block deformation and determining the subsidence of intervertebral body fusion devices.
1.5 Since some intervertebral body fusion devices require the use of additional implants for stabilization, the testing of these types of implants may not be in accordance with the manufacturer's recommended usage.
1.6 Units—The values stated in SI units are to be regarded as the standard with the exception of angular measurements, which may be reported in terms of either degrees or radians.
1.7 The use of this standard may involve the operation of potentially hazardous equipment. This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.