Kyphoplasty does not maintain all restored height postoperatively: a prospective, comparative study.

From January to December 2008, balloon kyphoplasty was performed on 45 consecutive female patients with primary single-segment vertebral compression fractures as an inpatient procedure. All of the treated vertebral bodies were located within the thora-columbar region (T11-L2). Demographic data such as age, body mass index, fracture age, hospital stay, lumbar spine bone mineral density, and amount of bone cement injected per vertebrae were recorded. Patients were analyzed clinically by ambulatory status and the visual analog scale (VAS) for pain. Lateral radiographs were used to measure changes in anterior vertebral height. Mean anterior vertebral height increased from 58.9%+/-12.50% pre-kyphoplasty to 79.8%+/-7.12% post-kyphoplasty (P<.001).Two groups were defined based on the percentage of height restoration achieved: group A (18 patients) with a height restoration of at least 20%, and group B (27 patients) with a height restoration of 0% to 19.99% post-kyphoplasty. Mean anterior vertebral height restored in groups A and B was 28.2%+/-7.2% and 12.1%+/-6.2%, respectively (P<.05). Four patients in group A and none in group B had height loss at the treated vertebral level (P<.05). Both VAS and ambulatory status were improved after treatment (P<.05) with no significant difference between the 2 groups. Kyphoplasty can restore the collapsed vertebral height, but patients with greater height restoration were more vulnerable to a loss of corrected height.