King ii aDolescent iDiopathic scoliosis (lenKe b anD c): preDiction oF coronal Decompensation

Objective: To identify the predictive radiographic signs of trunk decompensation in King II AIS patients (Lenke B and C) who underwent selective thoracic arthrodesis with third generation material. Methods. A retrospective analysis was carried out of the preoperative radiographies, and those from the most recent follow-up, of twenty-two patients. The sample was divided in two groups: patients compensated after treatment (n=18) and patients who presented coronal decompensation (n=4). The two groups were compared to analyze possible postoperative predictive radiographic criteria of trunk decompensation. Results: The patients who developed coronal trunk decompensation showed a greater angular value, greater apical vertebral translation (AVT) and rotation (AVR) of the lumbar curve, and greater L4 obliquity in relation to the pelvis. Furthermore, the relationship between the thoracic curve AVT and AVR, for the angular value criteria, was smaller than for the patients with good evolution. Conclusions: Compensatory lumbar curves with similar angular value to the main thoracic curve, with greater translation and rotation of the apical vertebra and greater L4 slope, have a high probability of trunk decompensation after this surgical treatment. The small number of decompensated patients did not enable any predictive values of these variables to be defined.