Preoperative Scoring System for Prediction of Early Adjacent Vertebral Body Fracture After Balloon Kyphoplasty Using X-Rays Taken in a Non-Weight-Bearing Position

Background: Prevention of adjacent vertebral body fracture (AVF) following balloon kyphoplasty (BKP) is a key challenge. The objective of this study was to develop a scoring system that could be more extensively and effectively used to determine the surgical indications for BKP. Methods: The study involved 101 patients aged 60 years or older who had undergone BKP. Logistic regression analysis was used to identify risk factors for early AVF within 2 months following BKP. Scoring was based on the odds ratio for risk factors, and cut-off values were determined from the receiver operating characteristics curve. The correlation between the total scores and the incidence of early AVF, and the area under the curve for the logistic regression model predicting early AVF using the scoring system were investigated. Results: 29 cases (28.7%) experienced early AVF after BKP. The scoring system was created as follows: 1) age (<75 years: 0 points (P), ≥75 years: 1P), 2) number of previous vertebral fractures (0: 0P, 1 or more: 2P), and 3) local kyphosis (<7°: 0P, ≥7°: 1P). The total scores were found to be positively correlated with the incidence of early AVF (r = 0.976, P = 0.004). The area under the curve of the scoring system for predicting early AVF was 0.796. The incidence of early AVF was 4.2% at ≤1P and 44.3% at ≥2P (P < 0.001). Conclusions: A scoring system which can be applied to a broader patient population was developed. In cases where the total score is 2P or more, alternatives to BKP should be considered.