1072 SIJ Fusion Device Testing

Abstract

INTRODUCTION: Screw use for SIJ fixation began in the 1980s with the FDA first classifying SIJ fusion devices in 2002. For 40 years, no standardized test method existed. Various methodologies (for bone screw, intramedullary nail, or spinal fusion implants) were modified to accommodate the design and function of sacroiliac devices including ASTM F543’s torsion, pullout, and insertion tests, ASTM F1264’s three- or four-point bending tests, and ASTM F2193’s cantilever bending tests. For many years, SIJ fusion screw indications were limited to fixation of pelvic bones for sacroiliac joint disruptions and degenerative sacroiliitis. While the FDA typically accepted performance testing according to combinations of the aforementioned tests, the specific test expectations have been relatively undefined with inconsistent testing batteries from submission to submission. METHODS: Collaboration among testing experts, manufacturers, and FDA regulators within ASTM’s Spinal Devices sub-committee resulted in the development and publication of ASTM F3574 (Standard Test Methods for Sacroiliac Joint Fusion Devices) based on physiologic loading conditions in the joint as documented in published studies. These tests included: For SI Screws: • Static/dynamic cantilever bending •Static torsion •Driving torque •Pullout For SI Posterior Spacers: •Static/dynamic shear •Static/dynamic torsion. RESULTS: The medical device industry now has access to standardized test methods for SI devices while the FDA or other regulators now have device specific test methods to recommend for pre-clinical testing. CONCLUSIONS: Many new standards drag through years of development and refinement within sub-committees, but ASTM F3574 developed quickly due to efforts of the Spinal sub-committee task group to meet the needs for SI fusion devices.