A spine or spinal rod has a cross-section defining angled sides that cooperate with a spinal rod opening of a spinal rod holder. In one form, the spine rod has an essentially pentagonal cross-section that thus essentially defines angled sides or side surfaces that interact with the spinal rod holder opening to positively seat the spine rod into the spinal rod holder and prevent spine rod from rotation. In the pentagonal cross-section form, the spine rod has a top or posterior side/side surface, a bottom or anterior side/side surface, a first lateral side/side surface, a second lateral side/side surface, a first angled sub-lateral side/side surface and a second angled sub-lateral side/side surface. The first and second angled sub-lateral sides/side surfaces provide contact with angled sides of the spine rod holder opening. In another form, the spine rod has an essentially V-shaped cross-section that defines sides/side surfaces that interact with the spinal rod holder opening. Preferably, but not necessarily, the spine rod is formed of PEEK. Other bio-compatible materials, however, may be used.