Satisfactory restoration of thoracic kyphosis in Lenke I AIS curves using bilateral vertebral coplanar alignment: an international multicenter experience

Review of a prospective multicenter registry. To report the correction of the thoracic sagittal profile in Lenke 1 curves using the bilateral vertebral coplanar alignment (BVCA) maneuver. All-pedicle-screw construtcs provide satisfactory coronal correction but fail to accurately restore the frequent thoracic hypokyphosis of Lenke 1 curves. BVCA is a recently described technique focused on restoration of the normal thoracic kyphosis alignment in AIS patients. A non-consecutive series of 49 AIS patients underwent surgical correction of the deformity by only posterior pedicle screw construct. Coronal and sagittal curve correction was assessed by conventional standing X-rays at preoperative and 2-year follow-up visits. BVCA reduction maneuvers include the correction of the deformity, while descending an implantable rod within slotted tubes attached to the convex side screws. Restoration of physiologic kyphosis is achieved by spreading the distal ends of the tubes at the thoracic spine using different-sized spacers. Mean preoperative Cobb of the MT curves was 58.4° and was corrected at 70.9%. Preoperative apical vertebral rotation was 18.6° on average and was corrected at 52.9%. T5–T12 kyphosis showed a significant improvement from a mean angle of 18.8º (95% CI 13.3–24.8) to 23.5º (95% CI 20.1–26.1) at 2-year follow-up (a 25% increase) (p = 0.040). Patients with (−) sagittal modifier gained 13.9º on average; those with ( +) modifier decreased 24.0°, and patients with N sagittal modifier remained almost unchanged (2.9°). Differences in the changes of the thoracic sagittal profile between the three groups were statistically significant (p < 0.001). After surgical correction of scoliosis, 87.8% of the patients were considered normokyphotic. Clinical results have proven the ability of BVCA to obtain good correction of the deformity in the coronal plane, similar to other methods. However, this technique permits a more relevant restoration of thoracic kyphosis.