title: MRI features of the psoas major muscle in patients with low back pain.
abstract: OBJECTIVE
  The purpose was to investigate the changes of the psoas major muscles (PM) cross-sectional area (CSA) and fat infiltration in the PM and to investigate the association between the morphology of the PM and expression of the degenerative changes of lumbar spine in patients with low back pain (LBP).
  
  
  METHODS
  T2-weighted scans for measurements of the CSA and analysis of fat infiltration were performed on 42 patients and 49 controls using a 1.5 Tesla MR system. For a quantitative analysis of fat tissue infiltration a 4-grade visual scale was used.
  
  
  RESULTS
  Patients had bigger CSA of the PM than controls at the levels of L3/L4 and L4/L5 intervertebral disc (P < 0.05). Patients with apparent degenerative changes of the lumbar spine had smaller CSA of the PM compared to the patients without apparent changes at the levels of L3/L4 and L4/L5 (P < 0.05). At the levels of L4/L5 and L5/S1 patients with present Modic changes in the lumbar vertebral bodies showed smaller CSA of the PM compared to the patients without Modic changes (P < 0.05). However, CSA of the PM in the patients with degenerative changes of lumbar spine and Modic changes was still bigger than the one of the controls. At all analyzed levels correlation between CSAs of the PM and fat infiltration of the lumbar paraspinal muscles was negative.
  
  
  CONCLUSIONS
  Results suggest increased activity of the PM in LBP patients but PM also remains active regardless of the presence of degenerative and Modic changes of the lumbar spine.
authors.affiliation: Department of Anatomy, School of Medicine, Br. Branchetta, 20, 51000, Rijeka, Croatia, juraj.arbanas@medri.uniri.hr.
authors.forename: Juraj
authors.initials: J
authors.lastname: Arbanas
authors.forename: Ivan
authors.initials: I
authors.lastname: Pavlovic
authors.forename: Verner
authors.initials: V
authors.lastname: Marijancic
authors.forename: Hrvoje
authors.initials: H
authors.lastname: Vlahovic
authors.forename: Gordana
authors.initials: G
authors.lastname: Starcevic-Klasan
authors.forename: Stanislav
authors.initials: S
authors.lastname: Peharec
authors.forename: Snjezana
authors.initials: S
authors.lastname: Bajek
authors.forename: Damir
authors.initials: D
authors.lastname: Miletic
authors.forename: Daniela
authors.initials: D
authors.lastname: Malnar
mesh_terms: D000273:Adipose Tissue / Q000473:pathology; D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D006801:Humans; D055959:Intervertebral Disc Degeneration / Q000473:pathology*; D017116:Low Back Pain / Q000473:pathology*; D008159:Lumbar Vertebrae / Q000473:pathology*; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D064170:Paraspinal Muscles / Q000473:pathology; D016658:Psoas Muscles / Q000473:pathology*; D012447:Sacrum / Q000473:pathology; D055815:Young Adult
references.citation: Man Ther. 2008 Feb;13(1):43-9
references.pmid: 17070721
references.citation: Behav Modif. 1998 Jan;22(1):62-77
references.pmid: 9567737
references.citation: Man Ther. 2008 Aug;13(4):349-56
references.pmid: 17556006
references.citation: Spine (Phila Pa 1976). 1998 Apr 15;23(8):928-31
references.pmid: 9580961
references.citation: Radiology. 2007 Oct;245(1):43-61
references.pmid: 17885180
references.citation: Eur Spine J. 2007 Jul;16(7):977-82
references.pmid: 17334791
references.citation: Spine (Phila Pa 1976). 2006 Aug 1;31(17):1888-99
references.pmid: 16924205
references.citation: AJNR Am J Neuroradiol. 2008 May;29(5):838-42
references.pmid: 18272564
references.citation: Spine (Phila Pa 1976). 2005 May 15;30(10):1173-80
references.pmid: 15897832
references.citation: Eur Spine J. 2000 Aug;9(4):266-72
references.pmid: 11261613
references.citation: Clin Radiol. 2000 Feb;55(2):145-9
references.pmid: 10657162
references.citation: Eur Spine J. 2002 Feb;11(1):89-90
references.pmid: 11931072
references.citation: Eur Spine J. 2006 Jun;15(6):764-73
references.pmid: 15895259
references.citation: Clin Biomech (Bristol, Avon). 1992 May;7(2):109-19
references.pmid: 23915688
references.citation: Spine (Phila Pa 1976). 1993 Jun 1;18(7):830-6
references.pmid: 8316880
references.citation: Arthritis Res Ther. 2003;5(3):120-30
references.pmid: 12723977
references.citation: Spine (Phila Pa 1976). 2005 Dec 1;30(23):2621-30
references.pmid: 16319748
references.citation: Br J Radiol. 2011 Aug;84(1004):709-13
references.pmid: 21081573
references.citation: Spine (Phila Pa 1976). 2004 Nov 15;29(22):E515-9
references.pmid: 15543053
references.citation: Spine (Phila Pa 1976). 2001 Sep 1;26(17):1873-8
references.pmid: 11568697
references.citation: BMC Med. 2007 Jan 25;5:2
references.pmid: 17254322
references.citation: Eur Spine J. 2000 Dec;9(6):577-85
references.pmid: 11189930
references.citation: Radiology. 2006 Sep;240(3):786-92
references.pmid: 16926328
references.citation: Spine (Phila Pa 1976). 1995 Apr 15;20(8):928-35
references.pmid: 7644958