A method for rotating a vertebra or vertebrae in a spine that is curved using a vertebral osteosynthesis device that includes polyaxial screws, linking rods, clamping parts, tightening nuts, and set screws. The method includes the steps of: implanting two series of the screws, clamping parts, and linking rods completely tightening the tightening nuts of a first series of screws on the convex side of the spine curvature completely tightening the set screws of a second series of screws on the concave side of the spine curvature tightening the tightening nuts of the second series and tightening the set screws of the first series.
