Abstract
Percutaneous vertebroplasty (PVP), where vertebral bodies are injected with polymethylmethacrylate (PMMA) cement, is used to treat various spinal lesions. Although the complication rate for PVP is low, thermal damage caused by the exothermic curing of PMMA has been implicated.
This study was to measure the temperatures reached during PVP as PMMA cures as well as assessing the cement volume effect and inter cement differences. Validating spinal cord monitoring during PVP was also undertaken.
In the in vivo experiment each of the lumbar vertebral bodies of 10 sheep were injected with one of two cements and one of two volumes. Thermocouple monitoring was undertaken at the bone cement interface. While undertaking the in vivo experimental studies 6 sheep underwent epidural monitoring using Motor Evoked Potentials (MEPs).
The mean peak temperature at the bone-cement interface was 49.5 C (3.0ml Simplex); 61.47 C (6.0ml Simplex); 42.1 C (DePuy 3ml) and 47.2 (DePuy 6ml). Spinal cord monitoring showed that when cement was injected into the correct location within the trabeculae of the vertebral body no change in amplitude monitoring was noted. When leakage occurred, deliberate or unintended, amplitude changes were noted.
Using cement volumes similar to those used in human clinical practice in a sheep model we were able to monitor temperature changes. The temperature of the bone cement interface reached temperatures that are known to cause tissue necrosis. Using epidural monitoring we were able to detect leakage of cement during injection.
The abstracts were prepared by Editorial Secretary Jean-Claude Theis. Correspondence should be addressed to NZOA at Department of Orthopaedic Surgery, Dunedin Hospital, Private Bag 1921, Dunedin, New Zealand.
