Interventional Spine

Verka Beric, FRCR, Keith Greenfield, PhD, Non ASSR Member

Scientific Paper

Purpose

Cortoss, Orthovita, is a high-strength, bone-bonding, composite engineered specifically to mimic the strength characteristics of human cortical bone. Unlike polymethylmethacrylate (PMMA), the orthopedic bone cement that is often used "off-label" in vertebral augmentation procedures, Cortoss has been engineered for the treatment of vertebral compression fractures. Cortoss is the only product in Europe approved for use in vertebral augmentation including the repair of vertebral compression fractures caused by osteoporosis and invasive tumors on the basis of prospective clinical data. Cortoss is not currently available for commercial distribution in the United States. The clinical efficacy of Cortoss for vertebral augmentation is examined at ultra-low injection volumes.

Methods & Materials

Twenty patients were treated with Cortoss for osteoporotic vertebral fracture. A maximum of three levels were injected during each procedure. Prevertebroplasty, 1 week and 1 month postvertebroplasty VAS, SF36 and ODI questionnaires were completed. Ten patients were treated with the more viscous preparation introduced in mid-2005.

Results

An average of 1.9 vertebrae were injected per procedure. The average volume of Cortoss injected was 0.5 ml per vertebra. This compares with 5-10 ml volumes of PMMA commonly used in each vertebra. Immediate pain relief was noted in the majority of patients with average VAS improvement of 49 points. Improvements in SF36 and ODI were observed also. One clinically nonsignificant leak occurred in the central pulmonary vasculature with the more liquid preparation, due to the low injected volume this was not clinically apparent.

Conclusion

Unlike PMMA, Cortoss interdigitates with the trabeculae providing a scaffold-like filling pattern, and thereby allowing lower volumes of material to be injected than traditionally administered with PMMA. As the Cortoss-to-bone interface continues to be strengthened over time, even with ultra-low volumes of Cortoss, there is a significant clinical improvement in patient symptoms. Importantly, this low volume reduces the risk of complications associated with the procedure due to extravasation. Cortoss is easier to use than PMMA, is as effective, even at ultra-low volume, and therefore, likely to be safer than PMMA for use in vertebroplasty.