The effect of surgical correction of Lenke types I and III scoliotic deformities on the spinal balance in patients aged 15–35 years

Objective. To analyze the effect of spinal deformity correction on the parameters of the frontal and sagittal balance in patients aged 15-35 years with Lenke types I and III idiopathic scoliosis. Material and Methods. The dynamics of sagittal and frontal parameters of the spinal balance was assessed in 268 patients aged 15 to 35 years with Lenke type I and III idiopathic scoliosis before and after surgical treatment. The patients’ quality of life and the number of postoperative complications were assessed depending on the imbalance severity. Results. More than half of patients (55.6 %) with Lenke types I and III idiopathic scoliosis have initial balance disorders, and 14.6 % of them have pronounced abnormalities. Significant balance disorders are predicted by severe scoliosis (85.3° ± 30.3°), greater L5 tilt (10.3 ± 7.9 before surgery; 5.3 ± 4.8 after surgery) and initial sagittal imbalance (32.75 ± 27.7), large residual scoliotic curve (43.3° ± 23.1°), large angle of residual thoracic kyphosis (32.3° ± 15.9°), and smaller angle of lumbar lordosis after surgery (52.3° ± 14.1°); p < 0.05. The main compensatory elements, in addition to PT and SS, are the angle of L5 tilt in the frontal plane and the L5–S1 angle in the sagittal plane. In young patients aged 15-35 years, disc mobility at the L5–S1 level is sufficient to achieve a more balanced body position, even with a significant change in the PI-LL ratio. Conclusion. In the long-term postoperative period, a pronounced imbalance of the spine increases the risk of mechanical postoperative complications up to 50 %, while the quality of life of patients does not decrease, and repeated surgical interventions are required in singular cases. Correction of scoliotic deformity allows increasing the number of patients without balance disorders by 6 %, and reducing the number of gross deviations by 2 times.