A surgical implant is used for imparting stability to the thoraco-lumbar spine by fixation of the implant to the spine with segmental spinal instrumentation. The implant comprises a unitary rod having a generally rectangular configuration formed by a pair of spaced apart branches, mirror image duplicated of one another and equally spaced apart along their entire length. A bight end piece interconnects the branch pair at the superior end portion thereof while a gate forming end piece closes the inferior end portion of the branch pair except for a small gate opening. The gate opening facilitates sublaminar wiring for fixation of the implant to the spine.
