Radiological outcome of postoperative sagittal balance on standing radiographs in comparison to intraoperative radiographs in prone position when performing lumbar spinal fusion.

Measuring lordosis angles intraoperatively resulted in almost the same values as measurements in standing plane radiographs postoperatively, despite prone position. These findings could especially be shown for the level L4-S1. The intraobserver reliability was almost perfect for both, intra- and postoperative measurements. In conclusion, the intraoperative measurement of a lumbar lordosis angle can perfectly predict the postoperative result.