Adult degenerative deformity: principles of sagittal balance, classification and surgical management

Deformity has always been part of the gradual spinal degenerative process occurring in older ages causing pain and disability. The shift of the adult population towards older ages has rendered this entity a much more frequent problem requiring treatment. Restoration of global balance is important to achieve pain relief and improve health related quality of life. Advances in the understanding of the spinal balance provided insight into the goals of surgical treatment. Moreover, progress of instrumentation expanded the spectrum of possible operations. However, the altered bone biology and presence of medical co-morbidities define the surgical limitations and restrict the number of patients who are fit to undergo such major surgery. This article reviews the fundamental principles of spinal balance and clinical aspects of adult deformity. There is no doubt that surgical correction plays an important role in the management of this condition but this is not indicated for all patients. Indications for deformity correction and treatment options are discussed. Finally the complications are presented as this is an important parameter for a sound patient selection process.