title: Asymmetry of the cross-sectional area of paravertebral and psoas muscle in patients with degenerative scoliosis.
abstract: OBJECTIVE
  This study was undertaken to assess the change of psoas and paravertebral muscles in patients with degenerative scoliosis.
  
  
  METHODS
  Eighty-five patients with degenerative scoliosis were evaluated with simple radiography for the location and direction of the apex of scoliosis, coronal Cobb's angle, rotational deformity and lumbar lordosis, and with magnetic resonance imaging scan at the apex level of each patient, the cross-sectional area (CSA) and the fatty infiltration rate (FI) of bilateral paravertebral and psoas muscles were measured and the values of convex and concave side were compared.
  
  
  RESULTS
  Fifty-three patients had apex of curves on the left side and thirty-two patients on the right. The mean Cobb's angle was 17.9°. The difference index of CSA (CDI) of psoas and multifidus muscle at apex of curvature level was significantly larger in convex side rather than that in concave side (by 6.3 and 8.4 % with P = 0.019 and 0.000, respectively). FI of each muscle showed no significant difference.
  
  
  CONCLUSIONS
  Hypertrophy of the muscles on the convex side is suggested as the explanation of this asymmetry rather than atrophy of the muscles on the concave side as muscle atrophy is known to be associated with increased fatty infiltration.
authors.affiliation: Department of Orthopaedic Surgery, Seoul National University College of Medicine, Seoul National University Hospital, 101 Daehang-no, Chongno-gu, Seoul, 110-744, Korea.
authors.forename: Hyoungmin
authors.initials: H
authors.lastname: Kim
authors.forename: Choon-Ki
authors.initials: CK
authors.lastname: Lee
authors.forename: Jin S
authors.initials: JS
authors.lastname: Yeom
authors.forename: Jae Hyup
authors.initials: JH
authors.lastname: Lee
authors.forename: Jae Hwan
authors.initials: JH
authors.lastname: Cho
authors.forename: Sang Ik
authors.initials: SI
authors.lastname: Shin
authors.forename: Hui-Jong
authors.initials: HJ
authors.lastname: Lee
authors.forename: Bong-Soon
authors.initials: BS
authors.lastname: Chang
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D064170:Paraspinal Muscles / Q000473:pathology*; D016658:Psoas Muscles / Q000473:pathology*; D011859:Radiography; D012600:Scoliosis / Q000000981:diagnostic imaging / Q000473:pathology*