High density all-pedicle screw technique in correction of high-degree (≥70 degrees) scoliosis with sequential derotation without osteotomies

Abstract

Background: Pedicle screws have become the principal method for scoliosis correction by allowing secure segmental three-column fixation, with many advantages over other fixation methods. This prospective study was conducted in 23 patients to evaluate the efficacy and safety of high-density pedicle screws in the correction of high degrees (≥70 degrees) of adolescent idiopathic scoliosis with sequential derotation without osteotomies. Methods: The traditional posterior approach was done with pedicle-screw instrumentation at each level of the concave side unless the pedicle was hypoplastic or markedly deformed and could not support pedicle-screw purchase. For the convex side, the surgeons instrumented at least the three lower-most vertebrae, three upper-most vertebrae, and at least three apical vertebrae. The mean preoperative Cobb angle of the major curve was 82.34 degrees. Results: The Cobb angle had been corrected to 19.65 degrees postoperatively and to 20.69 degrees at latest follow-up. The percent of curve correction was 76.1%. The Scoliosis Research Society (SRS) 22 questionnaire score improved significantly from a mean of 2.3 preoperatively to 3 at latest follow-up. There was no metal failure or pseudarthrosis detected during the follow-up period. The high-density screw technique allows control of each vertebra in the curve. Using a tough rod with a rod derotation technique aligns the coronal position of each vertebra. Conclusions: A high-density pedicle-screw technique through a posterior-only approach is a safe, effective method for treatment of severe adolescent idiopathic scoliosis avoiding the anterior approach-related complications. Level of Evidence: Level IV.