Sixty-five consecutive scoliosis patients, 25 with idiopathic deformities and 40 with postpoliomyelitis deformities, were treated by preoperative correction, segmental spinal instrumentation with arthrodesis, and no postoperative immobilization. The follow-up ranged from 12 to 25 months (average, 18 months); no patients was lost to follow-up. The initial deformity varied from 35 degrees to 140 degrees (average, 69 degrees), and the final correction varied from 53% to 93% (average, 72%). The average loss of correction was 1.5 degrees, or 2%. The complications in this group were two infections and two pseudoarthroses. The author believes that segmental spinal instrumentation gives a planned maximum correction of scoliotic deformities, provides a satisfactory method of rigid internal fixation of the spine that needs no external fixation, and leads to rapid efficient arthrodesis.