Instrumentation techniques to prevent proximal junctional kyphosis and proximal junctional failure in adult spinal deformity correction—a systematic review of biomechanical studies

Background context Correction of adult spinal deformity (ASD) by long segment instrumented fusion is an increasingly common surgical intervention. However, it associated with high rates complications and revision surgery, especially in the elderly patient population. The construct stiffness thoracolumbar has been postulated to lead a higher incidence proximal junctional kyphosis (PJK) failure (PJF). Several cadaveric biomechanical studies have reported on techniques reduce PJF/PJK. As yet, no overview made these studies. Purpose To summarize evidence all that assessed PJK/PJF following ASD Study design A systematic review. Methods EMBASE MEDLINE databases were searched for human animal investigating effect various Studied techniques, test methods, range motion (ROM), intervertebral disc pressure (IDP) other relevant outcome parameters documented. Results Twelve met inclusion criteria. Four included non-human material. One study investigated prophylactic application cement augmentation (vertebroplasty), whereas remaining semi-rigid fixation achieve gradual transition zone forces at end construct, so-called topping-off. An increased terms ROM compared pedicle screw constructs was demonstrated sublaminar tethers, tape, pretensioned suture loops, transverse hooks laminar hooks. Furthermore, reduced IDP found after tapes Finally, two-level vertebroplasty resulted lower vertebral compression fractures flexion-compression experiment. Conclusions variety involving either posterior or reinforcement bodies, biomechanically assessed. low number variation protocols hampers direct comparison different techniques. determination what constitutes optimal its translation clinical practice, would aid further development Even though biomechanics are extremely important PJK/PJF, patient-specific factors should always be taken into account case-by-case basis when considering apply technique.