title: The influence of fat infiltration of back extensor muscles on osteoporotic vertebral fractures.
abstract: METHODS
  Retrospective study.
  
  
  OBJECTIVE
  To investigate the influence of fat infiltration at low back extensor muscles on osteoporotic vertebral fracture.
  
  
  BACKGROUND
  In persons with stronger back muscles, the risk of osteoporotic vertebral fractures will likely be lower than in those persons with weaker back muscles. However, the degree of influence of fat infiltration of the back extensor muscle on osteoporotic vertebral fracture remains controversial.
  
  
  METHODS
  Two hundred and thirty-seven patients who had undergone lumbar spine magnetic resonance imaging and bone mineral density (BMD) were enrolled in this study. The amount of low back extensor muscle was determined using the pseudocoloring technique on an axial view of the L3 level. The patients were divided into two groups: osteoporotic vertebral fracture group (group A) and non-fracture group (group B). The amount of low back extensor muscle is compared with BMD, degenerative change of disc, osteophyte grade of facet joint and promontory angle to reveal the association between these factors.
  
  
  RESULTS
  A negative correlation is found between age and the amount of low back extensor muscle (p=0.001). The amount of low back extensor muscle in group A and group B was 60.3%±14.5% and 64.2%±9.3% respectively, thus showing a significantly smaller amount of low back extensor muscle in the osteoporotic vertebral fracture group (p=0.015).
  
  
  CONCLUSIONS
  Fat infiltration of low back extensor muscle was increased in osteoporotic vertebral fracture patients. Therefore, fat infiltration of low back extensor muscle in an elderly person may be a risk factor of osteoporotic vertebral fracture.
authors.affiliation: Department of Orthopedic Surgery, Kwangju Christian Hospital, Gwangju, Korea.
authors.forename: Kwang-Young
authors.initials: KY
authors.lastname: So
authors.affiliation: Department of Orthopedic Surgery, Kwangju Christian Hospital, Gwangju, Korea.
authors.forename: Dae-Hee
authors.initials: DH
authors.lastname: Kim
authors.affiliation: Department of Orthopedic Surgery, Kwangju Christian Hospital, Gwangju, Korea.
authors.forename: Dong-Hyuk
authors.initials: DH
authors.lastname: Choi
authors.affiliation: Department of Orthopedic Surgery, Kwangju Christian Hospital, Gwangju, Korea.
authors.forename: Choong-Young
authors.initials: CY
authors.lastname: Kim
authors.affiliation: Department of Orthopedic Surgery, Kwangju Christian Hospital, Gwangju, Korea.
authors.forename: Jeong-Seok
authors.initials: JS
authors.lastname: Kim
authors.affiliation: Department of Orthopedic Surgery, Kwangju Christian Hospital, Gwangju, Korea.
authors.forename: Yong-Soo
authors.initials: YS
authors.lastname: Choi
keywords: Back extensor muscle; Bone mineral density; Fat infiltration; Osteoporotic vertebral fracture