Clinical and radiographic results of balloon kyphoplasty for treatment of vertebral body metastases and multiple myelomas.

Kyphoplasty is a minimally invasive procedure that is used to augment vertebral body strength. This technique has been commonly used to treat osteoporotic, vertebral body compression fractures. The technique was also used to augment painful metastatic vertebral fractures. The objective of this study was to review the clinical and radiological results after kyphoplasty in patients with vertebral body compression fractures due to spinal metastasis and multiple myeloma and to determine factors that may affect outcome. Thirty-one patients had 41 vertebral body fractures secondary to spinal metastasis or multiple myeloma. A kyphoplasty procedure was performed on 39 levels. The pain and neurological status were evaluated using the visual analogue scale (VAS) score and the American Spinal Injury Association classification scale scores, respectively. Radiological evaluations were used to measure vertebral body height loss (VBHL) and the segmental kyphosis angle before and after surgery. The major symptoms that patients presented with included pain (25 patients); and neurological deficit (four patients). Two patients presented with no symptoms because the metastases were found during cancer screening. The mean (+/-standard deviation [SD]) VAS score was 7.2+/-2.2 before surgery and 1.6+/-1.3 after surgery. The mean preoperative VBHL was 27.8+/-11.3% for the thoracic spine and 27.7+/-12.5% for the lumbar spine. VBHL values were reduced to 22.4+/-10.0% and 18.4+/-10.4% for the thoracic and lumbar spine after surgery, respectively. The segmental kyphosis angles decreased from 21.2+/-11.4 degrees to 17.0+/-9.8 degrees for the thoracic spine and from 15.3+/-8.8 degrees to 10.4+/-7.2 degrees for the lumbar spine after surgery. There was a correlation between the symptom duration and VBH restoration rate. There was no correlation between the amount of injected polymethylmethacrylate and pain relief. We concluded that kyphoplasty is a safe and effective procedure for treating painful vertebral body fractures caused by metastasis and multiple myeloma. It can restore VBH and correct the kyphosis angle. While the increased amount of the injected PMMA led to its leakage, it did not contribute to restoration of the VBH or kyphosis correction. Therefore, one should avoid injection of excessive amounts of PMMA.