HYOMEX: a miniature universal testing machine for in vivo biomechanical studies

A miniaturized universal testing machine, HYOMEX, designed for biomechanically testing spinal structures of an anaesthetized research animal, such as a pig, is presented. A variety of mechanical applications such as static and dynamic tests, creep and relaxation tests, and fatigue tests with frequencies up to 20 Hz are possible. The system permits force control as well as displacement control. Continuous surveillance is made possible through interfacing the system to a computer. An application is presented where the viscoelastic behaviour in a porcine lumbar spine was measured.