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.Summary of Background Data.
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).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.Conclusion.
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.