Measuring, preserving, and restoring sagittal spinal balance.

The past decade has witnessed dramatic improvement in understanding and treatment of sagittal plane deformity. The authors have reviewed several studies that have clarified normative values for sagittal plane geometry as well as the role of the pelvis as we understand it today. In the treatment of lumbar degenerative disease with a fusion procedure, proper patient positioning and adherence to a thoughtful surgical plan are critical in the preservation of sagittal balance. In the event that restoration of sagittal alignment is required, it is best accomplished by the use of osteotomies, the techniques for which are described.