Three types of sagittal alignment regarding compensation in asymptomatic adults: the contribution of the spine and lower limbs
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A comprehensive understanding of normative sagittal profile is necessary for adult spinal deformity. Roussouly described four sagittal alignment types based on sacral slope, lumbar lordosis, and location of lumbar apex. However, the lower limb, a newly described component of spinal malalignment compensation, is missing from this classification. This study aims to propose a full-body sagittal profile classification in an asymptomatic population based on full-body imaging.
This is a retrospective analysis of a prospective single-center study of 116 asymptomatic volunteers. Cluster analysis including all sagittal parameters was first performed, and then ANOVA was performed between sub-clusters to eliminate the non-significantly different parameters. This loop was repeated until all parameters were significantly different between each sub-cluster.
Three types of full-body sagittal profiles were finalized according to cluster analysis with ten radiographic parameters: hyperlordosis type (77 subjects), neutral type (28 subjects), and compensated type (11 subjects). Radiographic parameters included knee angle, pelvic shift, pelvic angle, PT, PI–LL, C7–S1 SVA, TPA, T1 slope, C2–C7 angle, and C2–C7 SVA. Age was significantly different across compensation types, while BMI and gender were comparable. Age-matched subjects were randomly selected with 11 subjects in each type. ANOVA analysis revealed that all parameters but PT and C2–C7 angle remained significantly different.
The current three compensation types of full-body sagittal profiles in asymptomatic adults included significant changes from cervical region to knee, indicating that subjects should be evaluated with full-length imaging. All three types exist regardless of age, but the distribution may vary.
KeywordsAsymptomatic volunteers Sagittal alignment Full-body profile Lower limbs
The manuscript submitted does not contain information about medical device(s)/drug(s).
Compliance with ethical standards
Conflict of interest
All authors declare that they have no competing interest.
- 3.Nielsen D, Hansen L, Dragsted C, et al (2014) Clinical correlation of SRS-Schwab classification with HRQOL measures in a prospective non-US cohort of ASD patients. In: Int. Meet. Adv. Spine Tech. (IMAST), July 16–19Google Scholar
- 12.Protopsaltis TS, Schwab FJ, Bronsard N et al (2014) The t1 pelvic angle, a novel radiographic measure of global sagittal deformity, accounts for both spinal inclination and pelvic tilt and correlates with health-related quality of life. J Bone Joint Surg Am 96:1631–1640. doi: 10.2106/JBJS.M.01459 CrossRefPubMedGoogle Scholar
- 19.Diebo BG, Ferrero E, Lafage R et al (2015) Recruitment of compensatory mechanisms in sagittal spinal malalignment is age and regional deformity dependent: a full-standing axis analysis of key radiographical parameters. Spine (Phila Pa 1976) 40:642–649. doi: 10.1097/BRS.0000000000000844 CrossRefGoogle Scholar
- 22.Lafage R, Liabaud B, Diebo B et al (2016) Defining the role of lower limbs in compensating for sagittal malalignment. Presented at AAOS, Orlando, FLGoogle Scholar