[Risk factors for the collapse of cemented vertebral bodies after the minimally invasive vertebral augmentation procedures].

OBJECTIVE:To evaluate the incidence rate, the independent factors, and the prevention measures of the collapse of cemented vertebral bodies after minimally invasive vertebral augmentation procedures including percutaneous vertebroplasty (PVP) and percutaneous kyphoplasty(PKP). METHODS:From January 2012 to June 2013, 154 patients with single segmental osteoporotic vertebral compression fractures(OVCF)were treated with PVP or PKP. There were 65 males and 89 females, ranging in age from 57 to 90 years old, with a mean of (76.20±9.35) years old. All the patients were followed up, and the duration ranged from 6 to 30 months, with a mean of (15.43±6.81) months. All the patients were arranged to perform X-ray examination, and some of the patients were arranged to do MRI examination during the follow up period. Possible risk factors were studied including gender, age, surgical approach(PVP or PKP), lumbar spine bone mineral density, treated vertebral level, the presence of osteonecrosis in the vertebral body, filling pattern of the cement, and the restoration of anterior vertebral height. The Chi-square test and the multivariate Logistic regression model were used to analyze the risk factors. RESULTS:The collapse of cemented vertebral bodies were found in 29 patients, and the total incidence rate of following time was 18.83%. A Multivariable Logistic Regression analysis revealed that the independent risk factors affecting the incidence rate of the collapse included surgical approach (OR=0.171, P=0.010), lumbar spine bone mineral density(OR=0.242, P=0.024), the presence of osteonecrosis in the vertebral body(OR=12.225, P=0.003), filling pattern of the cement(OR=10.461, P=0.000), and anterior vertebral height restoration(OR=0.316, P=0.019). CONCLUSIONS:The incidence rate of the collapse was high and was associated with many risk factors. Surgical approach, lumbar spine bone mineral density, the presence of osteonecrosis in the vertebral body, filling pattern of the cement, and anterior vertebral height restoration were the independent risk factors affecting the incidence rate of the collapse. Careful selection of patients before operation, symmetric cement distribution and fluid aspiration during operation, positive treatment of osteoporosis after operation would be the potential ways to avoid collapse of cemented vertebral bodies.