Eighteen consecutive patients with scoliosis surgically treated by posterior correction and fusion were recruited. The major coronal curve averaged 65.8 degrees (range 51 degrees -87 degrees ). Eight patients were treated by hybrid constructs and four of them had anterior release before posterior surgery. Ten patients were treated by posterior correction and fusion alone with pedicle screw instrumentation. Flexibility was assessed by radiographs using the active bending and the fulcrum bending techniques. Two correction indices were not statistically different between the two groups. However, there was a tendency towards better correction in the screw group: mean surgical correction was 62.6+/-11.8% in the hook group and 71.6+/-12.3% in the screw group (p=0.07). Comparable pre- and post-operative radiographic results may indicate the advantages of posterior-only segmental pedicle screw instrumentation over hybrid constructs.