Stochastic analysis of multilevel artificial disc replacement and impact on spinal balance

Different opinions exist about the reasonability of total disc replacement in the human lumbar spine in the case that more than one natural disc should be replaced by an artificial one. Simulation of the biomechanical situations after surgery can help to estimate the reasonability of these procedures. The spinal shape during upright standing after surgery can be used to estimate clinical success. It is generally assumed that the body chooses such postures which require least energy, thus the spinal shape for standing after surgery can be determined by optimization, and judgments can be given as to how far multilevel disc replacement is sensible.