Segmental pedicle screw fixation in the treatment of thoracic idiopathic scoliosis.

STUDY DESIGN: This retrospective clinical study compared the results of correction of idiopathic thoracic scoliosis using Cotrel-Dubousset segmental pedicle screw fixation with those of hooks and screws inserted in a hook pattern.

OBJECTIVES: The study's objective was to evaluate the efficacy and safety of segmental pedicle screw fixation in the management of idiopathic thoracic scoliosis.

SUMMARY OF BACKGROUND DATA: Seventy-eight idiopathic thoracic scoliosis patients were treated with Cotrel-Dubousset instrumentation from 1987 to 1991. Thirty-one were treated with hooks; 23 were treated with pedicle screws inserted in a hook pattern; and 24 were treated with segmental pedicle screws.

METHODS: After a minimum follow-up of 2 years (range, 25-52 months), the results of frontal, sagittal, and rotational correction of each group were compared and statistically analyzed using analysis of variance.

RESULTS: Major curve correction was 55% with hooks, 66% with hook pattern screws, and 72% with segmental screws, with loss of correction of 6%, 2%, and 1%, respectively. Compensatory curve correction was 57% with hooks, 67% with hook pattern screws, and 70% with segmental pedicle screws. In patients with hypokyphosis, all showed significant improvement with best restoration in segmental screws. Rotational correction of the apical vertebra measured by the Perdriolle method was 19% with hooks, 26% with hook pattern screws, and 59% with segmental screws. Thirteen screws (3%) were malpositioned, but they did not cause neurologic impairment or adversely affect the results of treatment.

CONCLUSIONS: Segmental pedicle screw fixation is a safe and effective method for correcting the triplanar deformity of the idiopathic thoracic scoliosis.