Evaluation of Intraosseous Pressure during Pelvic Percutaneous Cement Injection: An In Vitro Study in Swine

BACKGROUND: A minimally invasive procedure for symptomatic pelvic bone metastasis is a feasible option for advanced cancer patients, and bone cement injection plays an essential role. Pulmonary embolism caused by thrombus, fat, or tumor emboli is a major complication related to bone cement injection, and increasing intraosseous pressure is a predisposing factor. This study aimed to quantify the degree of pressure change in the pelvic bone during percutaneous bone cement injection and investigate whether there is a significant decrease in intraosseous pressure when a decompressive route is additionally established. METHODS: Bone cement injection into the acetabulum of swine pelvises by simulating the actual surgical procedure in terms of the injection method, bone cement, and surgical instruments was performed while recording the intraosseous pressure. Twenty swine pelvises were used and grouped into a decompression group and a non-decompression group. Bone cement injection and pressure measurement were conducted in the same way in both groups, but an additional decompressive route was established for each pelvis in the decompression group. Continuous variables were compared using the Mann-Whitney test. RESULTS: The mean amount of injected bone cement was 19.8 mL and 20.3 mL and the mean speed of bone cement injection was 0.14 mL/sec and 0.12 mL/sec in the decompression group and the non-decompression group, respectively. The mean peak intraosseous pressures was 10.5 kPa with decompression and 37.8 kPa without decompression, and the difference was statistically significant (p < 0.01). CONCLUSIONS: Intraosseous pressure during bone cement injection into swine pelvises was similar to that during vertebroplasty or kyphoplasty. When the additional decompression route was established, the intraosseous pressure decreased to one third the level.