Predictive formula of ideal lumbar lordosis and lower lumbar lordosis determined by individual pelvic incidence in asymptomatic elderly population.

PURPOSE: This study aimed to obtain reference values of lumbar lordosis (LL) and lower LL (LLL) from normal asymptomatic groups, determine the relationship between them and pelvic incidence (PI), and establish the predictive formula for ideal LLL in the elderly Korean population. METHODS: Standing plain lateral radiographs of the whole spine, including the pelvis, were analyzed in asymptomatic adult male volunteers without back pain or prior surgery involving the spine or lower extremity. Volunteers with scoliosis, spondylolisthesis, segmental disk space narrowing, and/or compression fractures in the radiographs were excluded. The following parameters were measured: LL, LLL, and pelvic parameters including PI. The values of PI-LL and PI-LLL were calculated, and the formula using stepwise multiple regression analysis was made. A P value of < 0.05 was considered statistically significant. RESULTS: The study participants included 150 volunteers. All were male participants with an average age of 64.1 ± 6.4. The average value of height, weight, and body mass index was 167.0 ± 5.5 cm, 67.3 ± 9.8 kg, and 24.1 ± 3.1 kg/m2, respectively. The average LL was - 57.5° ± 9.0°, LLL was - 41.7° ± 7.0°, and PI was 48.6° ± 8.6°. The formula was established as follows: PI-LL = 0.38 × PI - 27.61 (R2 = 0.172), PI-LLL = 0.77 × PI - 28.69 (R2 = 0.516), ideal LL = 0.62 × PI + 27.61 (R2 = 0.348), and ideal LLL = 0.225 × PI + 28.63 (R2 = 0.083). CONCLUSIONS: The ideal values of PI-LL and PI-LLL were inconsistent, and they have a positive correlation with PI in asymptomatic elderly population. Our data would be helpful as a normal reference value of ideal LL and LLL according to PI. These slides can be retrieved under Electronic Supplementary Material.

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

INTRODUCTION: 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. MATERIALS AND METHODS: 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 (30.1° ± 8.6° vs. 21.1° ± 7.8° in Group 1, P < 0.001), thoracolumbar kyphosis (10.0° ± 7.5° vs. 2.8° ± 7.1° in Group 1, P < 0.001), total lumbar lordosis at T12-S1 (57.3° ± 8.8° vs. 52.2° ± 9.2° in Group 1, P < 0.001), lower lumbar lordosis at L4-S1 (39.4° ± 6.7° vs. 32.4° ± 6.4° in Group 1, P < 0.001), a higher ratio of lower to total lumbar lordosis (69.5 ± 11.6 vs. 62.7 ± 10.6 % in Group 1, P < 0.001) and T12 LEP-H angle (-20.4° ± 5.7° vs. -15.7° ± 5.1° in Group 1, P < 0.001). There were no significant differences in sacral slope (36.5° ± 7.3° in Group 1 vs. 36.8° ± 6.7° in Group 2, P = 0.67) and pelvic incidence (46.5° ± 7.7° in Group 1 vs. 48.2° ± 8.5° 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 ± 2.4 cm in Group 1 vs. -0.3 ± 2.7 cm in Group 2, P = 0.197). However, the distance from T12 plumb to the postero-superior endplate of S1 (-0.7 ± 1.7 cm in Group 1 vs. -2.2 ± 1.7 cm in Group 2, P < 0.001) demonstrated a significant difference. CONCLUSION: 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.