title: Sex differences in predicting chronicity of low-back pain after acute trauma using lumbar muscle area.
abstract: OBJECTIVE
  The aim of this study was to investigate sex differences in predicting chronicity of low-back pain after acute trauma using cross-sectional areas of paraspinal (multifidus and erector spinae) and psoas muscles.
  
  
  METHODS
  Between January 2006 and December 2010, a total of 54 patients were interviewed at least 6 mos after the trauma event. The subjects were classified into chronic low-back pain group and improved low-back pain group according to the presence of low-back pain for more than 6 mos. The cross-sectional area of the multifidus, erector spinae, and psoas muscles was measured at the level of the lower margin of the L3 and L5 vertebrae using magnetic resonance imaging.
  
  
  RESULTS
  The cross-sectional area of the multifidus and erector spinae muscles at L5 in the chronic low-back pain group was significantly smaller than that of the improved low-back pain group (P < 0.05) in the men. There were no significant differences in the other parameters between the groups in the men. There were no significant differences in any parameters in the women.
  
  
  CONCLUSIONS
  In the men, the cross-sectional area of the multifidus and erector spinae muscles at the lower lumbar level can be considered to be prognostic factors for the chronic low-back pain after acute trauma. The authors thus suggest that strengthening of lumbar paraspinal muscles could be helpful for preventing chronicity of low-back pain.
authors.affiliation: From the Department of Rehabilitation Medicine, CHA Bundang Medical Center, CHA University, Gyeonggi-do, Republic of Korea. The new affiliation for Dr. Ryu is Department of Rehabilitation Medicine, Seoul National University Bundang Hospital, Seoul National University College of Medicine, Seongnam, Korea.
authors.forename: Hak Il
authors.initials: HI
authors.lastname: Lee
authors.forename: Seok Tae
authors.initials: ST
authors.lastname: Lee
authors.forename: MinYoung
authors.initials: M
authors.lastname: Kim
authors.forename: Ju Seok
authors.initials: JS
authors.lastname: Ryu
mesh_terms: D000328:Adult; D019567:Back Injuries / Q000150:complications / Q000473:pathology*; D059350:Chronic Pain / Q000209:etiology* / Q000473:pathology*; D005260:Female; D006801:Humans; D017116:Low Back Pain / Q000209:etiology / Q000473:pathology*; D008159:Lumbar Vertebrae; D008279:Magnetic Resonance Imaging; D008297:Male; D064170:Paraspinal Muscles / Q000473:pathology*; D011237:Predictive Value of Tests; D016658:Psoas Muscles / Q000473:pathology*; D012189:Retrospective Studies; D012307:Risk Factors; D012737:Sex Factors; D055815:Young Adult