title: Painful lumbar spondylolysis among pediatric sports players: a pilot MRI study.
abstract: BACKGROUND
  For children and adolescents who are very active athletes, fresh lumbar spondylolysis is the main pathologic cause of lower back pain (LBP). However, regarding the terminal-stage spondylolysis (pars defect), there have been few studies to clarify the pathomechanism of LBP. The purpose of this study is to clarify the cause of LBP associated with pars defects in athletes. This is the first report showing a possible pathomechanism of LBP in active athletes with painful pars defect.
  
  
  METHODS
  Six pediatric athletes (5 boys and 1 girl) below 18 years old with painful bilateral lumbar spondylolysis were evaluated. In all cases, spondylolysis was identified as terminal stage (pseudoarthrosis) on CT scan. To evaluate the inflammation around the pars defects, short time inversion recovery (STIR) MRI was performed along with the sagittal section. Fluid collection, which is an indicator of inflammatory events, was evaluated in 12 pars defects as well as in 12 cranial and caudal adjoining facet joints.
  
  
  RESULTS
  Inflammation (i.e., fluid collection) was observed in all 12 pars defects in six subjects at the pseudoarthrotic pars defects. In terms of facet joints, 7 of 12 (58%) pars defects showed fluid collection at the cranial and/or caudal adjoining joints on STIR MRI.
  
  
  CONCLUSIONS
  The present study showed that inflammation was always present at the pars defects and in some cases at the adjoining facet joints. Thus, it is not difficult to understand how, during sports activity, inflammation may first occur at the pseudoarthrotic site and then spread to the adjoining facet joints. This mechanism could cause LBP associated with terminal-stage (pseudoarthrotics) spondylolysis in athletes.
authors.affiliation: Department of Orthopedic Surgery, Teikyo University Mizonokuchi Hospital, 3-8-3 Mizonokuchi, Takatsu-ku, Kawasaki 213-8507, Japan. sairyokun@hotmail.com
authors.forename: Koichi
authors.initials: K
authors.lastname: Sairyo
authors.forename: Toshinori
authors.initials: T
authors.lastname: Sakai
authors.forename: Yasuyoshi
authors.initials: Y
authors.lastname: Mase
authors.forename: Tamiyo
authors.initials: T
authors.lastname: Kon
authors.forename: Isao
authors.initials: I
authors.lastname: Shibuya
authors.forename: Yasuo
authors.initials: Y
authors.lastname: Kanamori
authors.forename: Tatsuo
authors.initials: T
authors.lastname: Kosugi
authors.forename: Akira
authors.initials: A
authors.lastname: Dezawa
mesh_terms: D000293:Adolescent; D002648:Child; D005260:Female; D006801:Humans; D017116:Low Back Pain / Q000209:etiology*; D008159:Lumbar Vertebrae; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D010865:Pilot Projects; D011446:Prospective Studies; D013169:Spondylolysis / Q000150:complications*; D013177:Sports