Figure 4From: Biomechanical evaluation of immediate stability with rectangular versus cylindrical interbody cages in stabilization of the lumbar spineThe Dartec® (Stourbridge, UK) material testing machine, with a spine model in the testing jig. A spine model is mounted in the jig, for eccentric loading using a 10 cm lever arm. 'P' indicates the position of the 50 N preload, applied through a 40 cm lever arm, in the opposite direction from the fulcrum, at the bottom end of the specimen.Back to article page