A spinal plating system for vertebral fixation includes a plate, a compression screw, multiple fixation members and polyaxially adjustable locking rings. The plate is shaped to conform to the curvature of the spine and the surfaces of the vertebral bodies. The compression screw fits through an insert, and together they are guided by the plate as the screw is driven into one of the vertebrae, producing compression between the adjacent vertebrae. A retaining lip on the plate prevents backout of the compression screw. The polyaxial locking rings can be polyaxially pivoted to attain a desired orientation, and are lockable to the plate to maintain the orientation. The fixation members fit through openings in the polyaxial locking rings and the plate to fix the plate to the vertebrae. Locking the polyaxial locking rings fixes the position of the fixation members relative to the plate, and prevents backout of the fixation members.