The biomechanics of spondylolysis and spondylolysthesis

The etiology and predisposing factors of spondylolysis and spondylolysthesis have received considerable attention, but little on their biomechanics has been published. The goal of our article is to demonstrate a biomechanical model for the development of spondylolysis and spondylolysthesis. With mechanical equations it has been established that the mechanics of the development of spondylolysis and spondylolysthesis is similar, the spondylolysthesis occurs only if the ligament breaks. The development of spondylolysis and spondylolysthesis depends greatly on the strength of the pars interarticularis and the ligaments. The other important question is overloading of the spine, which can come from hyperextensed or hyperflexed movement, etc