LAUSR

OBJECTIVE Bone cement augmentation procedures (vertebroplasty and kyphoplasty) are the primary treatments for osteoporotic vertebral compression fracture (VCF). However, these procedures are associated with various problems resulting in subsequent fracture. The purpose of this study was to evaluate the spinal instability factors related to subsequent fracture after vertebral augmentation procedures. METHODS We retrospectively reviewed patients who underwent augmentation procedures for osteoporotic VCF. Between May 2011 and November 2014, 285 patients (vertebroplasty, n = 231; kyphoplasty, n = 54) were enrolled. Subsequent fractures were classified into 4 types based on the fracture patterns: 1) no subsequent fracture, 2) neofracture, 3) hammer fracture (new vertebral fractures involving another vertebra without a definitive history of trauma), and 4) kyphotic compression fracture. We analyzed subsequent fracture patterns and their occurrence rates according to factors that may induce subsequent fracture and developed a predictive scoring system with respect to the hammer fracture occurrence rate. We classified all cases into 4 groups (A,B,C,D) according to Spinal Instability Predictive Scoring System score. Groups A, B, C, and D were defined by total scores of 0∼5, 6∼10, 11∼15, and 16∼20, respectively. RESULTS The subsequent fracture types for vertebroplasty were as follows: no subsequent fracture (n = 112; 48.28%); hammer fracture (n = 65; 28.02%); neofracture (n = 35; 15.09%); and kyphotic compression fracture (n = 19; 8.19%). According to the total scores, the occurrence rate of subsequent hammer fracture (no subsequent fracture, hammer fracture, neofracture, and kyphotic compression fracture) were as follows: group A (84.21%, 0%, 10.52%, and 5.26%), group B (64.58%, 10.45%, 12.5%, and 12.5%), group C (39.39%, 33.3%, 15.15%, and 12.12%), and group D (11.67%, 63.3%, 21.67%, and 3.33%). CONCLUSIONS Predictive scores can be calculated and used to predict the possibility of subsequent fracture according to scores. Group D showed the highest predictive scores and will need more preventative treatment.