Doodkorte RJP, Vercoulen TFG, Roth AK, et al. - A systematic review was conducted to summarize data of all biomechanical studies that have assessed techniques to decrease proximal junctional kyphosis and proximal junctional failure (PJK/PJF) following long segment instrumented spinal fusion in the adult spinal deformity (ASD) patient population. Researchers carried out to search EMBASE and MEDLINE databases for human and animal cadaveric biomechanical studies evaluating the impact of various surgical techniques to decrease PJK/PJF following long segment instrumented thoracolumbar spinal fusion in the adult patient population. They biomechanically assessed a variety of techniques, involving either posterior semi-rigid junctional fixation or the reinforcement of vertebral bodies. Nevertheless, the low number of studies and variation in study protocols hampers direct comparison of different procedures. Moreover, determination of what constitutes an optimal gradual transition zone and its translation to clinical practice would aid comparison and future establishment of different semi-rigid junctional fixation methods. Patient-specific factors should always be taken into account on a case-by-case basis when considering to apply a semi-rigid junctional fixation technique, even though biomechanics are extremely important in the development of PJK/PJF.