Mechanical Analogue Model of the Human Lumbar Spine: Development and Initial Evaluation Available to Purchase

Mechanical testing of spinal instrumentation on cadaveric spine segments can be challenging. In this study, a mechanical analogue lumbar spine model was developed to be similar in rigidity to that of cadaveric spine segments. Three models of an adult human lumbar spine were built from composite vertebrae, ligaments and discs created individually to reproduce the nonlinear mechanical properties of human components. These models and three calf lumbar spines were loaded in a biaxial mechanical test system in axial compression, torsion, right and left lateral bending, flexion and extension. Rigidities were calculated in the secondary linear load-displacement region. Load-displacement behavior was nonlinear for both analogue and calf spines. There was good reproducibility between the models. Average axial rigidity of the analogue spines was 86 N/mm versus 231 N/mm for the calf spines, possibly due to the calf flat-back. In the remaining loading modes, the analogue spine was 26–65% more rigid than young calf spines. Comparisons to human cadaveric spine segments are underway.