The present invention relates to a dynamic fixation member adapted for implantation in a patient by posterior attachment to a first vertebra of a spine of the patient using a first pedicle screw and a first connector, and to a second vertebra using a second pedicle screw and a second connector, the dynamic fixation member comprising a first rod arm adapted for connection to the first pedicle screw by the first connector, and a second rod arm adapted for connection to the second pedicle screw by the second connector and a deformable portion connected to the first and second rod arms, the deformable portion including a plurality of branch segments interconnected by a plurality of hinges, wherein the plurality of branch segments and the plurality of hinges are configured around an opening, wherein at least three hinges of the plurality of hinges are oriented in a plane that is coplanar with the first and second pedicle screws wherein when implanted posteriorly in the patient, the dynamic fixation member allows controlled bending motion of the first vertebra relative to the second vertebra while limiting sagittal translation of the first vertebra relative to the second vertebra with lengthening and shortening of the deformable portion.
