This article is more than 5 years old. Information may no longer be current.
PMMA recommended over CaP for balloon kyphoplasty for osteoporotic fractures
Kyphotic endplate angle improved from –12° to –6°, with no significant loss of correction at 1 year.
Patients being treated for osteoporotic vertebral fractures by percutaneous balloon kyphoplasty fared better with polymethylmethacrylate than with calcium phosphate.
The researchers said calcium phosphate (CaP) should be reserved for osteoporotic Type AI fractures.
Trial participants had osteoporotic fractures of vertebral bodies in the thoracolumbar spine, a fracture age of less than 4 months, and were older than 65 years. Exclusion criteria consisted of tumor lesions and additional posterior instrumentation.
Investigators included 56 patients with 60 osteoporotic vertebral fractures in the study. Thomas R. Blattert, MD, PhD, presented the findings of this prospective, randomized clinical trial at the North American Spine Society annual meeting in Seattle.
|
|
Images: Blattert T. |
CaP vs. PMMA
Surgeons randomly applied CaP carbonate cement and polymethylmethacrylate (PMMA) to 30 cases each. All of the fractures were classified as Type A; of those, 19 were classified Type AIII, meaning the fracture left a posterior wall fragment. Fifty-two patients experienced postoperative pain relief, improving from 2.1 to 8.2 on the Visual Analog Scale. The kyphotic endplate angle improved from –12° to –6°.
Blattert and colleagues found no statistically significant difference between the groups regarding pain relief or restoration of the end plate angle after 1 year. The researchers performed clinical and radiological follow-ups at 1 day, 6 weeks, and 3, 6, and 12 months postoperatively.
|
|
Loss of correction
“The main complication … is the loss of correction in some of these patients visible on the native X-ray at 6 weeks postoperatively,” Blattert said. “They were all mended with the calcium phosphate, and they all were Type AIII fractures.”
He added that there was no loss of correction in Type AIII fractures with PMMA, whereas the CaP was fragmented, broken and showed a definite loss of correction.
“All calcium phosphate cements available right now have insufficient mechanical strength data in terms of lateral bending, shearing and extension,” he told Orthopedics Today.
The mechanical properties for PMMA were sufficient for the axial compression and lateral bending/extension; however, for CaP, the mechanical properties for lateral bending/extension were insufficient. The mechanical properties for axial compression were sufficient.
Although Blattert found PMMA was better than CaP for balloon kyphoplasty in osteoporotic burst fractures, there are risks when using cement. With PMMA, there was a higher risk of vascular embolism and cement extrusion, he said, while with CaP the hardening process was more problematic and there was a risk for substantial loss of correction in Type AIII fractures. Therefore CaP is not suitable for applications facing lateral bending, shearing or extension forces, ie, burst fractures, Blattert added.
|
|
|
For more information:
- Blattert TR. Suitability of calcium phosphate in osteoporotic vertebral body fractures – a prospective, randomized clinical trial of balloon kyphoplasty comparing calcium phosphate versus polymethylmethacrylate. #105. Presented at the North American Spine Society 21st Annual Meeting. Sept. 26-30, 2006. Seattle.
- Thomas R. Blattert, MD, PhD, chief consulting surgeon, Clinic for Trauma, Reconstructive and Plastic Surgery and Spine Center, Leipzig University Hospital, Leibigstr. 20, D-04103 Leipzig, Germany; +49-341-97-17-348; Thomas.blattert@medizin.uni-leipzig.de. He has no direct financial interest in the products discussed in this article. He is a paid consultant for Kyphon Europe Inc.