[Sagittal deformity. Basic principles of surgical strategies].

There is a large body of literature supporting the importance of restoring sagittal balance to the spine. The main message is this: regardless of the specific surgical strategy and treatment or pathology, rebalancing results in a positive patient outcome. Complex deformity patients need to be evaluated with attention to the global balance and the operative planning and strategy must be adapted accordingly. Spinal fusions are not always considered within the framework of sagittal balance. Unsuccessful outcome including continued pain, adjacent level disease, accelerated degenerative changes of the spine, pseudarthrosis and hip and knee changes, may then ensue. Certainly, those patients need to be re-evaluated with attention to the global balance of the spine. The reason for the outcome may be sagittal imbalance and osteotomy techniques as well as fusion extension may be needed. The postoperative outcome can only be improved when the sagittal balance is already considered in the planning and treatment strategy during initial correction surgery. Concerning sagittal balance a paradigm shift seems to occur.