A system for treating a spinal deformity in a skeletally mature or immature spine comprising: at least three vertebral anchor means for anchoring into three different vertebral bodies (100,101,101'), respectively, the vertebral anchor means optionally being positionable in the vertebral bodies in a non-linear manner; and at least one flexible interconnection means for attaching to the vertebral anchor means in a non-linear manner, the flexible interconnection means being rigidly attached to at least two vertebral anchor means and attached to an intermediate vertebral anchor means through a gliding interconnection, wherein the flexible interconnection means either: constrains spinal growth in at least one direction thereby creating tension on at least one of the vertebral anchor means and the flexible interconnection means, causing the resulting flexible interconnection means to be less non-linear after growth than the flexible interconnection means prior to spinal growth, wherein the tension causes a tensioning of the interconnecting elements, thereby causing a rotation of the intermediate vertebrae due to interaction with the flexible interconnection means; or permits deliberate intervertebral alignment changes by intra-operatively tensioning the flexible interconnecting means, thereby creating tension on at least one of the vertebral anchor means and the flexible interconnection means, causing the resulting flexible interconnection means to be less non-linear after growth than the flexible interconnection means prior to spinal growth, wherein the tension causes a distraction of the vertebral anchor means at the end vertebrae, thereby causing a rotation of the intermediate vertebrae due to interaction with the flexible interconnection means, characterised in that the intermediate vertebral anchor means comprises a head, a lower member positioned beneath the head, a connecting passage provided by or defined between a bottom portion of the head and an upper portion of the lower member, a threaded passage and a blocking screw which can be seated in the threaded passage and permits a firm locking of the flexible interconnection means to the head, the gliding interconnection being provided or facilitated by the connecting passage. at least three vertebral anchor means for anchoring into three different vertebral bodies (100,101,101'), respectively, the vertebral anchor means optionally being positionable in the vertebral bodies in a non-linear manner; and at least one flexible interconnection means for attaching to the vertebral anchor means in a non-linear manner, the flexible interconnection means being rigidly attached to at least two vertebral anchor means and attached to an intermediate vertebral anchor means through a gliding interconnection, wherein the flexible interconnection means either: constrains spinal growth in at least one direction thereby creating tension on at least one of the vertebral anchor means and the flexible interconnection means, causing the resulting flexible interconnection means to be less non-linear after growth than the flexible interconnection means prior to spinal growth, wherein the tension causes a tensioning of the interconnecting elements, thereby causing a rotation of the intermediate vertebrae due to interaction with the flexible interconnection means; or permits deliberate intervertebral alignment changes by intra-operatively tensioning the flexible interconnecting means, thereby creating tension on at least one of the vertebral anchor means and the flexible interconnection means, causing the resulting flexible interconnection means to be less non-linear after growth than the flexible interconnection means prior to spinal growth, wherein the tension causes a distraction of the vertebral anchor means at the end vertebrae, thereby causing a rotation of the intermediate vertebrae due to interaction with the flexible interconnection means, constrains spinal growth in at least one direction thereby creating tension on at least one of the vertebral anchor means and the flexible interconnection means, causing the resulting flexible interconnection means to be less non-linear after growth than the flexible interconnection means prior to spinal growth, wherein the tension causes a tensioning of the interconnecting elements, thereby causing a rotation of the intermediate vertebrae due to interaction with the flexible interconnection means; or permits deliberate intervertebral alignment changes by intra-operatively tensioning the flexible interconnecting means, thereby creating tension on at least one of the vertebral anchor means and the flexible interconnection means, causing the resulting flexible interconnection means to be less non-linear after growth than the flexible interconnection means prior to spinal growth, wherein the tension causes a distraction of the vertebral anchor means at the end vertebrae, thereby causing a rotation of the intermediate vertebrae due to interaction with the flexible interconnection means,