A pre-assembled spine stabilization system configured to be implanted into adjacent vertebral bodies, said system comprising: - a first bone fastener, including a head and a shaft that extends form the head; - a second bone fastener, including a head and a shaft that extends form the head; - a first tulip assembly comprising a first tulip element, having a first saddle and a first ring, and a second tulip element, wherein the first tulip element of the first tulip assembly is configured to attach to the first bone fastener; - a second tulip assembly comprising a first tulip element, having a second saddle and a second ring, and a second tulip element, wherein the first tulip element of the second tulip assembly is configured to attach to the second bone fastener; - a first rod member that extends from the first tulip assembly to the second tulip assembly, wherein the first rod member is disposed on the first saddle and the second saddle; and - a second rod member that extends from the first tulip assembly to the second tulip assembly, characterized in that - the first bone fastener is retained in the pre-assembled first tulip assembly via the first ring engaging a lower portion of the first bone fastener head and the second bone fastener is retained in the pre-assembled second tulip assembly via the second ring engaging a lower portion of the second bone fastener head, - wherein the first saddle engages an upper portion of the first bone fastener head and the second saddle engages an upper portion of the second bone fastener head, - wherein the first ring is spaced apart from the first saddle and the second ring is spaced apart from the second saddle, and - wherein the first saddle is movable with respect to the first ring and the second saddle can is movable with respect to the second ring. - a first bone fastener, including a head and a shaft that extends form the head; - a second bone fastener, including a head and a shaft that extends form the head; - a first tulip assembly comprising a first tulip element, having a first saddle and a first ring, and a second tulip element, wherein the first tulip element of the first tulip assembly is configured to attach to the first bone fastener; - a second tulip assembly comprising a first tulip element, having a second saddle and a second ring, and a second tulip element, wherein the first tulip element of the second tulip assembly is configured to attach to the second bone fastener; - a first rod member that extends from the first tulip assembly to the second tulip assembly, wherein the first rod member is disposed on the first saddle and the second saddle; and - a second rod member that extends from the first tulip assembly to the second tulip assembly, characterized in that - the first bone fastener is retained in the pre-assembled first tulip assembly via the first ring engaging a lower portion of the first bone fastener head and the second bone fastener is retained in the pre-assembled second tulip assembly via the second ring engaging a lower portion of the second bone fastener head, - wherein the first saddle engages an upper portion of the first bone fastener head and the second saddle engages an upper portion of the second bone fastener head, - wherein the first ring is spaced apart from the first saddle and the second ring is spaced apart from the second saddle, and - wherein the first saddle is movable with respect to the first ring and the second saddle can is movable with respect to the second ring.