Biomechanical assessment of the stabilization capacity of monolithic spinal rods with different flexural stiffness and anchoring arrangement.

摘要: Abstract Background Spinal disorders can be treated by several means including fusion surgery. Rigid posterior instrumentations are used to obtain the stability needed for fusion. However, abrupt stiffness variation between stabilized and intact segments leads proximal junctional kyphosis. The concept of spinal rods with variable flexural is proposed create a more gradual transition at end instrumentation. Method Biomechanical tests were conducted on porcine spine (L1–L6) assess stabilization capacity different stiffness. Dual-rod constructs containing three kinds (Ti, Ti–Ni superelastic, half stiff-half superelastic) implanted using two anchor arrangements: pedicle screws all levels or except upper instrumented vertebra in which case replaced transverse process hooks. Specimens loaded forward flexion, extension, lateral bending before after implantation constructs. effects specimen stiffness, mobility, intradiscal pressures, forces evaluated. Finding differences rod properties had moderate impact biomechanics when only used. this effect was amplified hooks as anchors. Interpretation Combining softer (Ti–Ni superelastic provided motion level applied less force anchors, potentially improving load sharing