title: Association Between Lumbar Spine Sagittal Alignment and L4-L5 Disc Degeneration Among Asymptomatic Young Adults.
abstract: METHODS
  Cross-sectional observational study on the relationship between the degrees of disc degeneration and sagittal alignment in asymptomatic healthy individuals.
  
  
  OBJECTIVE
  This study sought to determine whether the sagittal spine alignment subtype is related to the prevalence of lumbar disc degeneration.
  
  
  BACKGROUND
  Sagittal balance and spinopelvic parameters might be risk factors for disc degeneration.
  
  
  METHODS
  A total of 70 asymptomatic participants (36 women and 34 men) without regular physical activity were categorized according to the four subtypes of sagittal alignment proposed by Roussouly. All participants underwent magnetic resonance imaging of the lumbar spine (1.5T) and panoramic radiography of the spine. The degree of disc degeneration was graded using T2-weighted images according to the Pfirrmann classification. Spinopelvic parameters and vertebral curvatures were measured on digital panoramic radiographs using Surgimap software. Interobserver analyses for the Pfirrmann classification and spinopelvic parameters were assessed using the weighted Kappa and intraclass correlation coefficient (ICC), respectively.
  
  
  RESULTS
  The Kappa associated with disc degeneration classification was 0.79 (95% confidence intervals 0.72-0.87). The ICCs were excellent, with small confidence intervals for all spinopelvic parameters. The type II group (flat lordosis) showed a higher frequency of degenerated discs at L4-L5 (P = 0.03) than the type IV group (long and curved lumbar spine). No significant differences in disc degeneration were observed among the four subtypes at the other disc levels. We found a negative, moderate correlation between the spinopelvic parameters and the occurrence of disc degeneration in the type II group.
  
  
  CONCLUSIONS
  The Roussouly subtype II sagittal alignment is significantly associated with disc degeneration at L4-L5 in asymptomatic young adults. Our results support the hypothesis that spinal sagittal alignment plays a role in early disc degeneration.
  
  
  METHODS
  3.
authors.affiliation: Division of Radiology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, São Paulo, Brazil.
authors.forename: Rafael
authors.initials: R
authors.lastname: Menezes-Reis
authors.affiliation: Division of Radiology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, São Paulo, Brazil.
authors.forename: Gustavo Perazzoli
authors.initials: GP
authors.lastname: Bonugli
authors.affiliation: Division of Radiology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, São Paulo, Brazil.
authors.forename: Vitor Faeda
authors.initials: VF
authors.lastname: Dalto
authors.affiliation: Department of Biomechanics, Medicine, and Rehabilitation of the Locomotor Apparatus, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, São Paulo, Brazil.
authors.forename: Carlos Fernando Pereira
authors.initials: CFP
authors.lastname: da Silva Herrero
authors.affiliation: Department of Biomechanics, Medicine, and Rehabilitation of the Locomotor Apparatus, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, São Paulo, Brazil.
authors.forename: Helton Luiz Aparecido
authors.initials: HLA
authors.lastname: Defino
authors.affiliation: Division of Radiology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, São Paulo, Brazil.
authors.forename: Marcello Henrique
authors.initials: MH
authors.lastname: Nogueira-Barbosa
mesh_terms: D000328:Adult; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D055959:Intervertebral Disc Degeneration / Q000000981:diagnostic imaging*; D008159:Lumbar Vertebrae / Q000000981:diagnostic imaging*; D008161:Lumbosacral Region / Q000000981:diagnostic imaging*; D008279:Magnetic Resonance Imaging; D008297:Male; D011187:Posture; D055815:Young Adult