Sagittal balance and pelvic parameters--a paradigm shift in spinal surgery.

It has become evident in recent years that global assessment of spinal sagittal balance is necessary for optimal management of the degenerate spine. Pelvic parameters have been developed which appear to correlate well with the natural history of degenerative spine disorders and outcomes from surgery. Although these parameters have a limited evidence base, they are now in widespread use by spinal surgeons and, in particular, spinal deformity surgeons. It is necessary for all surgeons treating spinal pathology to have a working knowledge of the principles of spinal sagittal balance, to be able to recognise sagittal imbalance and its compensatory mechanisms. In this article we outline the main concepts of spinal sagittal balance and pelvic parameters and how these concepts are leading to a paradigm shift in the surgical management of spinal disorders. We propose that analysis of pelvic parameters of sagittal balance will form an essential part of the evaluation of new surgical techniques for spinal conditions.