Current concepts of adolescent idiopathic scoliosis

Adolescent idiopathic scoliosis (AIS) is a complex three-dimensional deformity of the spine, accompanied by frontal curves, fixed vertebral rotations, and a flattening of the sagittal physiological curves. The most important goal of treatment is to prevent spinal curve progression, because if the curves reach advanced degrees, they may cause systemic problems. In general, patients with curves up to 20-25 degrees are observed and given an exercise program; curves between 25-40 degrees are given thoraco-lumbar spinal braces; curves exceeding 40-45 degrees are best treated by surgery. Posterior spinal fusion (PSF) with instrumentation is the most common surgical procedure and remains gold standard for thoracic and double major curves, which account majority of AIS cases. Anterior approaches have some advantages, as they allow to achieve higher correction rates with a lower fusion level compared to posterior techniques, especially in the lumbar region. Among other advantages are also a smaller blood loss and a lower risk of neurologic injury. The development of new anesthetic techniques and of modern multimodal spinal cord monitoring have made surgical interventions more efficient, reliable, fast, safe and comfortable. The use of antifibrinolytic drugs (tranexamic and epsilon-aminocapronic acid) may reduce the perioperative blood transfusion requirement. 3D radiographic imaging methods enhance preoperative planning and postoperative evaluation. Intraoperative use of navigation systems give knowledge about curves in difficult anatomic situations.