Long before its current understanding, the concept of balance was common among spine surgeons dealing with deformities, but it was a hard one to transfer to clinical practice. Thanks to the pioneering work of Duval-Beaupere and followers, the idea of balancing the sagittal contour of the spine has gained scientific status and is now in the armamentarium of the skilled surgeon as the single most important tool to achieve superior clinical results in adult spinal deformity surgery.
Keywords: Adult spinal deformity; Anterior fusion; Posterior fusion; Sagittal balance; Sagittal profile.