Abstract
Introduction
Vertebral compression fracture (VCF) is a unique type of fractures involving the body of vertebrae. It is associated with a significant decline in functionality and poor quality of life. Osteoporosis, or decreased bone density, is one of the leading causes of VCF. It is commonly seen amongst elderly, especially in post-menopausal women. Vertebroplasty (VP) is a minimally invasive percutaneous technique that involves injecting cement into a pathologic vertebral body, with the aim of pain relief and deformity correction. It is considered the best next line of management when conservative management fails to control symptoms. Although considered minimally invasive, VP has ~1 to 5% risk of clinically evident complications. Where, cement extravasation is the most commonly reported in the literature. Cement viscosity is considered the single most important predictor of the risk of extravasation. Unfortunately, injecting high viscosity cement is difficult to utilize in real practice. We invented a new device capable of injecting high viscosity with ease and at a distance to avoid radiation. The aim of this study is to confirm the efficacy and safety of the new device on cadaveric vertebrae.
Materials and Methods For this prospective case-control cohort study, 126 osteoporotic vertebral bodies were harvested form 14 fresh whole human cadavers. DEXA scan and simple X-rays were performed on all specimens to confirm the diagnosis of osteoporosis, and to rule out any pre-existing fractures. A total of 80 vertebral were included in the study. Computer-randomization software was used to allocate specimens over two main groups, Conventional VP and New Device. Both groups were further subdivided into two subgroups, High-Viscosity and Low-Viscosity. A custom device was used on each vertebra to induce a compression fracture. All augmentations were done following the same method commonly practiced in clinical treatment. X-ray radiographs were used to measure and compare cement distribution within the body between groups.
Results
Injecting high viscosity cement was associated with a lower leakage volume compared with low viscosity cement, with a mean of 0.06cc for the Conventional VP and 0.08cc with the New Device. High viscosity cement was associated with no leakage into the spinal canal. It was also associated with a low incidence of vascular extravasation (p < 0.001). The mean volume of cement leakage in the low viscosity group was 0.23cc and 0.15cc, for the Conventional VP and New Device respectively. In both groups, the most common site for leakage was the vertebral end plate, which was exhibited more in the low viscosity group (71.5%) compared with the high viscosity group (42.5%). The preset target amount of cement to be injected was reached in 99% of the time when injecting high viscosity cement with the New Device, compared with 62% using the Conventional VP. In both groups, there was no correlation between the amount of cement injected and the amount of leakage.
Conclusion
The new device is capable of injecting high viscosity cement easily, with a lower incidence of cement leakage. It also minimized the risk of radiation exposure to the surgeon.