title: Variables associated with active spondylolysis.
abstract: METHODS
  Retrospective non-experimental study.
  
  
  OBJECTIVE
  To investigate variables associated with active spondylolysis.
  
  
  METHODS
  A retrospective study audited clinical data over a two year period from patients with suspected spondylolysis that were referred for a SPECT bone scan. Six exploratory variables were identified and analysed using uni- and multi-variate regression from 82 patient records to determine the association between symptomatic, physical and demographic characteristics, and the presence of an active spondylolysis.
  
  
  METHODS
  Tertiary level multidisciplinary private practice sports medicine clinic.
  
  
  METHODS
  All patients with low back pain that required a SPECT bone scan to confirm suspected spondylolysis. 82 subjects were included in the final sample group.
  
  
  METHODS
  The six exploratory variables included Age, Gender, Injury duration, Injury onset, Sports participation and the result of the Single Leg Hyperextension Test. The dependent outcome variable was the result of the SPECT bone scan (scan-positive or scan-negative).
  
  
  RESULTS
  Adolescent males had a higher incidence of spondylolysis detected by SPECT bone scan compared to other patients and a statistically significant association was demonstrated for both age (p=0.01) and gender (p=0.01). Subjects with an active spondylolysis were nearly five times more likely to be male and aged less than 20 years. Furthermore, the likelihood ratio indicated that adolescent males with suspected spondylolysis were three and a half times more likely to have a positive bone scan result. The Single Leg Hyperextension Test did not demonstrate a statistically significant association with spondylolysis (p=0.47).
  
  
  CONCLUSIONS
  Clinicians assessing for a predisposition to the development of spondylolysis should consider the gender and age of the patient and not rely on the predictive ability of the Single Leg Hyperextension Test.
authors.affiliation: The Back Institute, 107 Mana Esplanade, Wellington, New Zealand. chris.gregg@tbihealth.co.nz
authors.forename: Chris D
authors.initials: CD
authors.lastname: Gregg
authors.forename: Sarah
authors.initials: S
authors.lastname: Dean
authors.forename: Anthony G
authors.initials: AG
authors.lastname: Schneiders
mesh_terms: D000293:Adolescent; D000328:Adult; D005260:Female; D006801:Humans; D017116:Low Back Pain; D008297:Male; D009520:New Zealand / Q000453:epidemiology; D016017:Odds Ratio; D012044:Regression Analysis; D012189:Retrospective Studies; D013169:Spondylolysis / Q000175:diagnosis* / Q000000981:diagnostic imaging / Q000453:epidemiology; D015899:Tomography, Emission-Computed, Single-Photon; D055815:Young Adult