The Effect of Changes in Segmental Lordosis on Global Lumbar and Adjacent Segment Lordosis After L5-S1 Anterior Lumbar Interbody Fusion.

The degree of compensatory loss of lordosis at the adjacent level L4-L5 correlated with the extent of segmental lordosis creation at the index L5-S1 level. This may suggest that the L4 to S1 segment acts as a "harmonious unit," able to accommodate only a certain amount of lordosis and further increases in segmental lordosis may be mitigated by loss of adjacent-level lordosis.