Classification of normal sagittal spine alignment: refounding the Roussouly classification

• Published in: European spine journal 2018-08, Vol.27 (8), p.2002-2011
• Main Authors: Laouissat, Féthi, Sebaaly, Amer, Gehrchen, Martin, Roussouly, Pierre
• Format: Article
• Language: English
• Subjects: Adolescent; Adult; Anthropometry - methods; Classification; Female; Healthy Volunteers; Hip; Humans; Lordosis - diagnostic imaging; Lordosis - pathology; Male; Medicine; Medicine & Public Health; Middle Aged; Neurosurgery; Original Article; Pelvic Bones - anatomy & histology; Pelvic Bones - diagnostic imaging; Pelvis; Population studies; Postural Balance; Prospective Studies; Radiography; Reference Values; Sacrum; Sacrum - anatomy & histology; Sacrum - diagnostic imaging; Spine (lumbar); Spine - anatomy & histology; Spine - diagnostic imaging; Surgical Orthopedics; Vertebrae; Young Adult
• ISSN: 0940-6719; 1432-0932
• DOI: 10.1007/s00586-017-5111-x

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  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.