Untreated severe scoliosis results in a serious malposition of the back, restrictive lung disease and increases mortality compared with the normal population. Idiopathic scoliosis rarely reaches a severe degree. In the treatment of severe scoliosis, preoperative head traction of several weeks' duration has proven a safe and effective method of correcting the malposition, and will also make scoliosis surgery technically easier. Most cases of severe scoliosis can be treated with anterior pedicle screw instrumentation, and vertebrectomy is only seldom required.