It for spinal fixation system (380) include that tail portion bar part (10) can be connected and skull bar part (30) can be with adjustment mechanism with regulating mechanism (20) in jointed rod assembly (5). Adjustment mechanism is constructed such that the bar part on tail portion and head surrounds joint shaft, the bar portion of tail portion perpendicularly to the longitudinal axis and head relative to each other. Rotation occurs outside in response to magnetic field. The adjustable size of the bar part on tail portion and head is that other pieces compatible of hardware is fixed for backbone, such as bone anchor (such as pedicle screw), occipitalia, pressure reducer, etc.. The bar portion on tail portion and head, can not be absorbed by strong, rigidity, biocompatible materials. Jointed rod assembly is advantageously used for spinal fixation system and method for spinal fixation.
