The outcome of three-dimensional correction on Lenke 5C adolescent idiopathic scoliosis by uniplanar pedicle screw combined with vertebral derotation technique

Objective To evaluate the outcome of three-dimensional correction by uniplanar pedicle screw combined with vertebral derotation technique for the treatment of Lenke 5C adolescent idiopathic scoliosis(AIS). Methods A retrospective review was conducted on patients with Lenke 5C AIS between February 2012 and August 2013. A total of 49 patients treated with posterior selective fusion by uniplanar or conventional pedicle screw were enrolled. Of these patients, 26 cases were included in the control group with an average age of 13.7 years old and the other 23 cases were included in the uniplanar pedicle screw(UPS) group with an average age of 13.2 years old. Patients were evaluated before surgery, after surgery and at the final follow-up in radiographic changes in lumbar and thoracic curve magnitude, thoracic kyphosis(TK), lumbar lordosis(LL) were evaluated in both groups. Apical vertebral rotation(AVR) were measured pre-and postoperatively by CT scans. Results After surgery, the average correction of the main curve was 75.9% and 77.5% in the control and UPS groups, respectively. No difference in the correction of the main curve magnitude between the two groups was observed. Corrections of AVR were 40.6%±16.5% in the control group and 57.4%±13.8% in the UPS group, showing a significant difference. No difference in the TK and LL was observed between the two groups. Patients were followed up for an average of 14.5 months in the control group and 13.6 months in the group UPS, showing no significant loss of correction. Conclusion Uniplanar pedicle screw provided a significantly better axial vertebral derotation as well as it can manage coronal misalignment and recover spine sagittal alignment effectively. Key words: Adolescent; Scoliosis; Spinal fusion; Bone screws