Classification of normal sagittal spine alignment: refounding the Roussouly classification

TY - JOUR

T1 - Classification of normal sagittal spine alignment

T2 - refounding the Roussouly classification

AU - Laouissat, Féthi

AU - Sebaaly, Amer

AU - Gehrchen, Martin

AU - Roussouly, Pierre

PY - 2018

Y1 - 2018

N2 - Purpose: Although the Roussouly classification of common variants in spinal sagittal alignment is well accepted, no studies have implemented it in an asymptomatic adult population. In addition, no study investigated the radiographic features of asymptomatic patients with an anteverted pelvis. The aim of this prospective radiographic study of 296 asymptomatic adults without spinal pathology was to investigate how the Roussouly classification could include the anteverted pelvis concept. Methods: Pelvic incidence (PI), sacral slope (SS), pelvic tilt (PT), and the lumbar parameters lumbar lordosis (Global LL), lordosis tilt angle (LTA), total number of lordotic vertebra (LL verteb), and C7 plumbline/sacrofemoral distance ratio (C7PL ratio) were evaluated in 296 healthy volunteers (126 males, 170 females; mean age, 27 years; range 18–48 years). Comparison between the five types of the Roussouly classification used Student, ANOVA, and Tukey tests for quantitative variables and χ 2 , Fischer, and Holm tests for qualitative variables. Results: Mean PI and PT were, respectively, (39°, 10°) for type 1, (41°, 10°) for type 2, (53°, 13°) for type 3, and (62°, 12°) for type 4 (p < 0.0001 and p < 0.01). A sizable portion (16%) of the population (type 3 AP) showed low-grade PI (mean, 48° ± 6°) despite having SS > 35°. PT was low or negative (mean 4° ± 3°). C7PL ratio was >1 (in front of the hip axis) in 13% of all cases, and between 0 and 1 (between sacrum and hip axis) in 49%. Conclusion: Although asymptomatic adults stood with stable global balance, the sagittal spinal alignment of healthy subjects, newly divided in 5 sagittal types, varied significantly. Type 3 AP appears as a new and unusual sagittal shape with low-grade PI, very low or negative PT, and hyperlordosis. Whereas most asymptomatic adults stood with C7PL behind the hip axis, a sizeable portion had C7 in front of the hip axis. This could be a new controversial aspect of ideal spinal balance.

AB - Purpose: Although the Roussouly classification of common variants in spinal sagittal alignment is well accepted, no studies have implemented it in an asymptomatic adult population. In addition, no study investigated the radiographic features of asymptomatic patients with an anteverted pelvis. The aim of this prospective radiographic study of 296 asymptomatic adults without spinal pathology was to investigate how the Roussouly classification could include the anteverted pelvis concept. Methods: Pelvic incidence (PI), sacral slope (SS), pelvic tilt (PT), and the lumbar parameters lumbar lordosis (Global LL), lordosis tilt angle (LTA), total number of lordotic vertebra (LL verteb), and C7 plumbline/sacrofemoral distance ratio (C7PL ratio) were evaluated in 296 healthy volunteers (126 males, 170 females; mean age, 27 years; range 18–48 years). Comparison between the five types of the Roussouly classification used Student, ANOVA, and Tukey tests for quantitative variables and χ 2 , Fischer, and Holm tests for qualitative variables. Results: Mean PI and PT were, respectively, (39°, 10°) for type 1, (41°, 10°) for type 2, (53°, 13°) for type 3, and (62°, 12°) for type 4 (p < 0.0001 and p < 0.01). A sizable portion (16%) of the population (type 3 AP) showed low-grade PI (mean, 48° ± 6°) despite having SS > 35°. PT was low or negative (mean 4° ± 3°). C7PL ratio was >1 (in front of the hip axis) in 13% of all cases, and between 0 and 1 (between sacrum and hip axis) in 49%. Conclusion: Although asymptomatic adults stood with stable global balance, the sagittal spinal alignment of healthy subjects, newly divided in 5 sagittal types, varied significantly. Type 3 AP appears as a new and unusual sagittal shape with low-grade PI, very low or negative PT, and hyperlordosis. Whereas most asymptomatic adults stood with C7PL behind the hip axis, a sizeable portion had C7 in front of the hip axis. This could be a new controversial aspect of ideal spinal balance.

KW - Anteverted pelvis

KW - Roussouly classification

KW - Sagittal balance

KW - Spinal alignment

U2 - 10.1007/s00586-017-5111-x

DO - 10.1007/s00586-017-5111-x

M3 - Journal article

C2 - 28455623

AN - SCOPUS:85018303289

SN - 0940-6719

VL - 27

SP - 2002

EP - 2011

JO - European Spine Journal

JF - European Spine Journal

IS - 8

ER -