Background
Pedicle screw fixation with a simple rod derotation maneuver enables a powerful coronal and sagittal plane correction in scoliosis surgery. However, the ability of achieving rotational correction is still unclear.
Purpose
To introduce a new technique, direct vertebral rotation, and to compare the surgical results of direct vertebral rotation with those of simple rod derotation.
Methods
Study Design: A prospective study.
- 38 adolescent idiopathic scoliosis patients treated with segmental pedicle screw fixation were analyzed.
- The first group (n = 17) was treated by direct vertebral rotation; the second group (n = 21) was treated by simple rod derotation.
- All patients had a minimum follow-up of 2 years.
- Having similar preoperative curve patterns, both groups were evaluated for the deformity correction, lower instrumented vertebral tilt, and spinal balance.
- Apical vertebral rotation was evaluated by computed tomography scans.
- Surgical techniques of direct vertebral rotation were as follows: a precontoured rod was inserted into segmental screws on the concave side in thoracic scoliosis; a simple rod derotation was performed; and then the screws on the juxta-apical vertebrae, both on concave and convex sides, were rotated opposite direction to the rod derotation.
- Then, all the screws were sequentially tightened.
Results
- In the direct vertebral rotation group, the average preoperative apical vertebral rotation of 16.7 degrees was corrected to 9.6 degrees, showing 42.5% correction, whereas in the simple rod derotation group, the correction was negligible from 16.1 degrees to 15.7 degrees (2.4%).
- In the direct vertebral rotation group, the average preoperative thoracic curve of 55 degrees was corrected to 12 degrees (79.6%), and the lumbar curve of 39 degrees was corrected to 7 degrees (80.5%).
- In the simple rod derotation group, the preoperative thoracic curve of 53 degrees was corrected to 17 degrees (68.9%), and the lumbar curve of 39 degrees was corrected to 16 degrees (62.2%).
- The average lower instrumented vertebral tilt correction was 80.6% and 66.3% in the directvertebral rotation and the simple rod derotation group, respectively.
- There were statistically significant differences in the coronal curve, lower instrumented vertebral tilt, and rotational correction (P < 0.05, Mann-Whitney U test).
- Thoracic kyphosis was improved in both groups.
Conclusions
Segmental pedicle screw fixation with "direct vertebral rotation" showed better rotational and coronal correction than "simple rod derotation."
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