title: Prospective analysis of magnetic resonance imaging accuracy in diagnosing traumatic injuries of the posterior ligamentous complex of the thoracolumbar spine.
abstract: METHODS
  Prospective cohort study.
  
  
  OBJECTIVE
  To study magnetic resonance imaging (MRI) accuracy in diagnosing posterior ligamentous complex (PLC) damage, when applying the new dichotomic instability criteria in a prospective cohort of patients with vertebral fracture.
  
  
  BACKGROUND
  Recent studies dispute MRI accuracy to diagnose PLC injuries. They analyze the complex based on 3 categories (intact/indeterminate/rupture), including the indeterminate in the ruptured group (measurement bias) in the accuracy analysis. Moreover, fractures with conservative treatment (selection bias) are not included. Both facts reduce the specificity. A recent study has proposed new criteria where posterior instability is determined with supraspinous ligament (SSL) rupture.
  
  
  METHODS
  Prospective study of patients with acute thoracolumbar fracture, using radiography and MRI (FS-T2-w/short-tau inversion-recovery sequences). 1. The integrity (ruptured/unruptured) of each isolated component of the PLC (facet capsules, interspinous ligament, SSL, and ligamentum flavum) was assessed via MRI and surgical findings. 2. PLC integrity as a whole was assessed, adopting the new dichotomic stability criteria from previous studies. In the MR images, PLC is considered ruptured when the SSL is found discontinued, and intact when not (this excludes the "indeterminate" category). In surgically treated fractures, PLC stability as a whole was assessed dynamically (ruptured/unruptured). In conservative fractures, PLC stability was assessed according to change in vertebral kyphosis measured with the local kyphotic angle at 2-year follow-up (ruptured if difference is > 5°/unruptured if difference is < 5°).3. Comparative analysis among findings provided MRI accuracy in diagnosing PLC damage.
  
  
  RESULTS
  Fifty-eight vertebral fractures were studied (38 surgical, 20 conservative), of which 50% were in males; average age, 40.4 years. MRI sensitivity for injury diagnosis of each isolated PLC component varied between 92.3% (interspinous ligament) and 100% (ligamentum flavum). Specificity varied between 52% (facet capsules) and 100% (SSL). PLC integrity sensitivity and specificity as a whole were 91% and 100%, respectively.
  
  
  CONCLUSIONS
  Adopting the new stability criteria, MRI accuracy in PLC injury diagnosis increases. Specificity is increased (true positives) both in isolated component analysis and PLC as a whole.
authors.affiliation: From the Department of Orthopaedic Surgery, Spine Unit, Hospital Universitario de Getafe, Madrid, Spain.
authors.forename: Javier
authors.initials: J
authors.lastname: Pizones
authors.forename: Felisa
authors.initials: F
authors.lastname: Sánchez-Mariscal
authors.forename: Lorenzo
authors.initials: L
authors.lastname: Zúñiga
authors.forename: Patricia
authors.initials: P
authors.lastname: Álvarez
authors.forename: Enrique
authors.initials: E
authors.lastname: Izquierdo
mesh_terms: D015331:Cohort Studies; D005260:Female; D006801:Humans; D017846:Longitudinal Ligaments / Q000473:pathology*; D008159:Lumbar Vertebrae / Q000293:injuries* / Q000473:pathology; D008279:Magnetic Resonance Imaging / Q000592:standards*; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D016037:Single-Blind Method; D016103:Spinal Fractures / Q000175:diagnosis* / Q000453:epidemiology; D013904:Thoracic Vertebrae / Q000293:injuries* / Q000473:pathology