Direct Vertebral Rotation (DVR): A New Technique of 3-D Deformity Correction with Segmental Pedicle Screw Fixation in Adolescent Idiopathic Scoliosis (AIS)

Abstract

Study Design: A prospective study. Objectives: To introduce a new technique, direct vertebral rotation (DVR), and to compare the surgical results with those of a simple rod derotation (SRD). Summary of Background Data: Pedicle screw fixation, with a simple rod derotation maneuver, enables powerful coronal and sagittal plane corrections in scoliosis surgery. However, the ability for rotational correction is still unclear. Methods: Thirty-eight AIS patients, treated with segmental pedicle screw fixation, were analyzed. The first group (n=17) was treated by DVR, and the second (n=21) by SRD. Having similar preoperative curve patterns, both groups were evaluated for the deformity correction and spinal balance. Results: In the DVR group, the average preoperative AVR of 16.7°was corrected to 9.6°, showing a 42.5% correction, while in the SRD group, the correction was negligible, from 16.1°to 15.7°(2.4%). In the DVR group, the preoperative thoracic curve of 55°was corrected to 12°(79.6%), and the lumbar curve from 39°to 7°(80.5%). In the SRD group, the preoperative thoracic curve of 53°was corrected to 17°(68.9%), and the lumbar curve from 39°to 16°(62.2%). The average LIVT correction was 80.6 and 66.3% in the DVR and SRD group, respectively. There were statistically significant differences in the coronal curve, LIVT and rotational correction (p<0.05, Mann-Whitney u test). Conclusions: The segmental pedicle screw fixation with ‘direct vertebral rotation’showed better rotational and coronal corrections than the ‘simple rod derotation’.