[Low cement distribution index is a risk factor for refracture of the adjacent segments after percutaneous vertebroplasty]

OBJECTIVE: To investigate the impact of cement distribution index on the occurrence of refracture in the adjacent segments after percutaneous vertebroplasty. METHODS: This retrospective analysis was conducted among 143 patients who received percutaneous vertebroplasty for osteoporotic vertebral compression fracture between April, 2011 and April, 2014. Of the 134 patients with complete follow-up data, 18 had adjacent segment fracture within 1 year following the surgeries (re-fracture group), and 116 patients without new fracture served as the control group. All the patients underwent X-ray examinations after the surgery and according to the position and shape, the cement in the vertebrae were classified into 5 types (Ⅰ to Ⅴ), and the volume-cubage index was computed based on the cement volume and vertebral cubage. Age, gender, bone mineral density (BMD), cement distribution index, volume-cubage index, and cement leakage were evaluated in the 2 groups, and the variables with significant differences between the 2 groups were analyzed in Logistic regression analysis. RESULTS: BMD was significantly lower and the rate of cement leakage was significantly higher in the re-fracture group than in the control group (P < 0.05). Significant difference was found in cement distribution index between the 2 groups (P < 0.05) but not in age, gender, cement volume or volume-cubage index (P>0.05). Logistic regression analysis indicated that BMD, cement leakage and cement distribution index all significantly affected the occurrence of adjacent vertebral fractures following percutaneous vertebroplasty. CONCLUSION: A low BMD, cement leakage and a low cement distribution index are all risks factor of adjacent vertebral fracture after percutaneous vertebroplasty.