Calcium phosphate cement leakage after percutaneous vertebroplasty for osteoporotic vertebral fractures: risk factor analysis for cement leakage

Object. The purpose of this study was to analyze the risk factors for leakage of calcium phosphate cement (CPC) after vertebroplasty for osteoporotic vertebral fractures and to determine whether the vertebral body (VB) leakage caused any changes in the therapeutic benefits. Methods. Between August 2000 and April 2002, the authors performed 65 CPC-assisted vertebroplasty procedures in 55 patients with thoracic or lumbar osteoporotic vertebral fractures. Back and low-back pain were evaluated using the visual analog scale and the duration of analgesic medication requirement. Factors related to CPC leakage and the postoperative outcome were analyzed. There was a small amount of VB CPC leakage in 23 cases. In 10 of 23 cases, leakage into the epidural space was found. Although VB CPC leakage was independently associated with high initial age, female sex, high bone mineral density (BMD), short injury-surgery interval, and injection via the unipedicular route in the logistic regression analysis, there was no factor associated with CPC leakage into the epidural space. Cement leakage into the epidural space reduced the immediate therapeutic effects on fracture-related pain (p = 0.0128). All patients in whom cement leaked into the epidural space had improved by the 2-week follow-up examination. Conclusions. Advanced initial age, female sex, high BMD, a short interval from injury to surgery, and injection via the unipedicular route may increase the incidence of CPC leakage. Cement leakage into the epidural space attenuated only the immediate therapeutic effects of CPC-assisted vertebroplasty.