title: Relationship between thoracic hypokyphosis, lumbar lordosis and sagittal pelvic parameters in adolescent idiopathic scoliosis.
abstract: OBJECTIVE
  Sagittal spine and pelvic alignment of adolescent idiopathic scoliosis (AIS) is poorly described in the literature. It generally reports the sagittal alignment with regard to the type of curve and never correlated to the thoracic kyphosis. The objective of this study is to investigate the relationship between thoracic kyphosis, lumbar lordosis and sagittal pelvic parameters in thoracic AIS.
  
  
  METHODS
  Spinal and pelvic sagittal parameters were evaluated on lateral radiographs of 86 patients with thoracic AIS; patients were separated into hypokyphosis group (n = 42) and normokyphosis group (n = 44). Results were statistically analyzed. The lumbar lordosis was lower in the hypokyphosis group, due to the low proximal lordosis. The thoracic kyphosis was not correlated with any pelvic parameters but with the proximal lordosis. The pelvic incidence was correlated with sacral slope, pelvic tilt, lumbar lordosis and highly correlated with distal lumbar lordosis in the two groups. There was a significant linear regression between thoracic kyphosis and proximal lordosis and between pelvic incidence and distal lordosis.
  
  
  CONCLUSIONS
  We can consider that the proximal part of the lordosis depends on the thoracic kyphosis and the distal part depends on the pelvic incidence. The hypokyphosis in AIS is independent of the pelvic parameters and could be described as a structural parameter, characteristic of the scoliotic deformity.
authors.affiliation: Department of Paediatric Orthopaedic Surgery and Scoliosis Surgery, Hôpital Pédiatrique CHU LENVAL, 57 avenue de la Californie, 06200, Nice, France, clement.jl@pediatrie-chulenval-nice.fr.
authors.forename: Jean-Luc
authors.initials: JL
authors.lastname: Clément
authors.forename: Anne
authors.initials: A
authors.lastname: Geoffray
authors.forename: Fatima
authors.initials: F
authors.lastname: Yagoubi
authors.forename: Edouard
authors.initials: E
authors.lastname: Chau
authors.forename: Federico
authors.initials: F
authors.lastname: Solla
authors.forename: Ioana
authors.initials: I
authors.lastname: Oborocianu
authors.forename: Virginie
authors.initials: V
authors.lastname: Rampal
mesh_terms: D000293:Adolescent; D001699:Biometry; D005260:Female; D006801:Humans; D007738:Kyphosis / Q000150:complications / Q000000981:diagnostic imaging*; D008141:Lordosis / Q000150:complications / Q000000981:diagnostic imaging*; D008159:Lumbar Vertebrae / Q000000981:diagnostic imaging; D008297:Male; D010384:Pelvic Bones / Q000000981:diagnostic imaging; D011859:Radiography; D012600:Scoliosis / Q000150:complications / Q000000981:diagnostic imaging*; D013131:Spine / Q000000981:diagnostic imaging*; D013904:Thoracic Vertebrae / Q000000981:diagnostic imaging