Beam-Like rods do not Provide Additional Improvement to Thoracic Kyphosis Restoration when Compared to Sagittal Reinforced rods in Adolescents Undergoing Spinal Fusion with Pedicle Screw Instrumentation for Idiopathic Scoliosis

Abstract

Operative treatment of adolescent idiopathic scoliosis (AIS) with posterior spinal fusion aims for three-dimensional correction of coronal curve and thoracic kyphosis. Our aim was to compare two different designs of asymmetrical rods in adolescents who underwent a posterior spinal fusion with pedicle screw instrumentation for AIS with an emphasis on thoracic kyphosis restoration. This study was made with 76 consecutive adolescents (mean age 15.6 years, SD 2.0). Thirty-nine patients were operated with sagittal reinforced rods and 37 patients were operated with beam-like rods. The clinical and radiological results were assessed preoperatively, postoperatively, and during the follow-up visits at the outpatient clinic 6 months and 2 years after the surgery. At the last follow-up, the mean (SD) major thoracic curves were 13° (6.2°) and 13° (6.0°) (P= 0.717). Correction percentages were 75% in the sagittal reinforced group and 73% in the beam-like rod group (P= 0.517). The mean (SD) thoracic kyphosis was 24° (11°) and 22° (7.8°) at the two year follow-up in the sagittal reinforced rod group and beamlike rod group (P= 0.517). There was a slight negative correlation between the major curve correction and thoracic kyphosis change in both groups, although this was not statistically significant (R=-0.19, P= 0.094 in the sagittal reinforced rod group, R=-0.16, P= 0.180 in the beam like rod group). There are no significant differences in the coronal or sagittal deformity restoration in adolescent patients who underwent a posterior spinal fusion with sagittal reinforced rods and beam-like rods for adolescent idiopathic scoliosis.