Abstract
Aim:
To establish whether there is a direct relationship between pelvic morphology and lumbar segmental angulation in the sagittal plane.
Methods:
40 lateral whole spine radiographs with normal sagittal profiles were reviewed. Pelvic incidence (PI), Lumbar Lordosis (LL), Thoracic Kyphosis (TK) and segmental angulation at each level from L1 to the sacrum were measured (from endplate to endplate) distinguishing the vertebral body and intervertebral disc contribution. Pearson correlation coefficients were used to analyse any relationship between pelvic parameters and segmental angulation.
Results:
A strong correlation was found between pelvic incidence and total lumbar lordosis and angulation at cephalad lumbar segments (L12, L23 and L34) P<0.0001 with the increased lordosis primarily (four fifths on average) found at the intervertebral disc. The proportion of total lumbar lordosis contributed at L45 and L5S1 reduced as pelvic incidence increased (P<0.0001).
Discussion:
PI can predict segmental angulation. Although the majority of lumbar lordosis is produced at L45 and L5S1, cephalad-lumbar segments sequentially become increasingly important as PI increases. This describes a continuum that allows segmental abnormalities to be identified when compensation in adjacent segments maintains normal total LL. It also paves the way for anatomical reconstruction in degenerative adult deformity based on pelvic morphology.
Conflict Of Interest Statement: No conflict of interest.
