A comparative analysis of sagittal spinopelvic alignment between young and old men without localized disc degeneration

The purpose of this study was to compare the sagittal spinopelvic parameters between young normal asymptomatic adults and older normal asymptomatic adults without localized segmental disc degeneration. Standing sagittal radiographs of the whole spine including the pelvis in 342 adult male volunteers (Group 1: n = 184, average age 21.2 years, range 19-28 vs. Group 2: n = 158, average age 63.8 years, range 53-79) were analyzed prospectively. Volunteers with history of spine operation, spinal disease, chronic pain in their back or legs, scoliosis, spondylolisthesis, 1-3 segmental disc space narrowing, and/or compression fractures in radiographs were excluded. The following parameters were included: thoracic kyphosis between T5 upper endplate (UEP) and T12 lower endplate (LEP), thoracolumbar kyphosis (T10 UEP - L2 LEP), T12 LEP-horizontal (H) angle (minus denotes EP above the H line), lumbar lordosis (T12 LEP - S1 UEP), lower lumbar lordosis (L4 UEP - S1 UEP), sacral slope, pelvic incidence and distances from C7 plumb/T12 plumb to the postero-superior endplate of S1. Group 2 (old men group) demonstrated larger thoracic kyphosis (30.1A degrees A A +/- A 8.6A degrees vs. 21.1A degrees A A +/- A 7.8A degrees in Group 1, P < 0.001), thoracolumbar kyphosis (10.0A degrees A A +/- A 7.5A degrees vs. 2.8A degrees A A +/- A 7.1A degrees in Group 1, P < 0.001), total lumbar lordosis at T12-S1 (57.3A degrees A A +/- A 8.8A degrees vs. 52.2A degrees A A +/- A 9.2A degrees in Group 1, P < 0.001), lower lumbar lordosis at L4-S1 (39.4A degrees A A +/- A 6.7A degrees vs. 32.4A degrees A A +/- A 6.4A degrees in Group 1, P < 0.001), a higher ratio of lower to total lumbar lordosis (69.5 +/- A 11.6 vs. 62.7 +/- A 10.6 % in Group 1, P < 0.001) and T12 LEP-H angle (-20.4A degrees A A +/- A 5.7A degrees vs. -15.7A degrees A A +/- A 5.1A degrees in Group 1, P < 0.001). There were no significant differences in sacral slope (36.5A degrees A A +/- A 7.3A degrees in Group 1 vs. 36.8A degrees A A +/- A 6.7A degrees in Group 2, P = 0.67) and pelvic incidence (46.5A degrees A A +/- A 7.7A degrees in Group 1 vs. 48.2A degrees A A +/- A 8.5A degrees in Group 2, P = 0.06). There was no significant difference in the measurement of distance from C7 plumb to the postero-superior endplate of S1 (-0.7 +/- A 2.4 cm in Group 1 vs. -0.3 +/- A 2.7 cm in Group 2, P = 0.197). However, the distance from T12 plumb to the postero-superior endplate of S1 (-0.7 +/- A 1.7 cm in Group 1 vs. -2.2 +/- A 1.7 cm in Group 2, P < 0.001) demonstrated a significant difference. The old men group demonstrated a significant increase in thoracic kyphosis, thoracolumbar kyphosis, total and lower lumbar lordosis, a higher ratio of lower to total lumbar lordosis, and a longer distance from T12 plumb to the postero-superior endplate of S1 without changes in sacral slope and global sagittal balance.