Risk factors of recompression of cemented vertebrae after kyphoplasty for osteoporotic vertebral compression fractures

Purpose To evaluate the risk factors correlated with loss of cemented vertebral body height after kyphoplasty in patients with osteoporotic vertebral compression fractures. Methods Thirty-four consecutive patients with single-level osteoporotic vertebral compression fractures who underwent kyphoplasty in the Affiliated Hospital of Jiangsu University between January 2012 and August 2014 were retrospectively analysed. Eight independent variables (age, gender, body mass index, pre-operative T-score in bone mineral density, the volume of polymethylmethacrylate injected, pre-operatively vertebral body height, the restoration of body height and the distance between polymethylmethacrylate and endplate) were assessed. The recompression of body height was the dependent variable. Multivariate linear regression analyses were used to determine the factors associated with recompression of body height. Results Multiple linear regression analyses indicated that the recompression of cemented vertebral body height was correlated with the distance between polymethylmethacrylate and endplate (P=0.008, b'=0.489). The final multiple linear regression model, which included only the distance between polymethylmethacrylate and endplate, resulted in a formula that accounted for 41.02 % of the recompression of body height. Conclusions The distance between polymethylmethacrylate and endplate is an important risk factor of recompression of cemented vertebrae after kyphoplasty for patients with osteoporotic vertebral compression fractures.