Ben Pradhan, Hyun W Bae

Study Design. Prospective, randomized, single-center study of Cortoss in the FDA Pivotal Vertebroplasty Study. This center enrolled 43 of the total 256 patients.
Introduction. Cortoss is an injectable bioactive, self-setting, radiopaque bone augmentation material shown to stabilize and provide immediate weight-bearing support to fractured vertebrae. This study assesses the safety and efficacy of the treatment of vertebral compression fractures with Cortoss compared to PMMA in the Multi-center Prospective Randomized Clinical Trial for Cortoss conducted under an FDA Investigational Device Exemption (G010122).
Methods. Twenty-two sites have enrolled 256 patients using a 2:1 randomization scheme (162 Cortoss, 94 PMMA). Patient outcomes were assessed by VAS, ODI, and SF-12. Patient evaluations were done at pre-op, pre- and post-treatment, 72-hous, 1-week, 1, 3, 6, 12, and 24-months. Inclusion criteria consisted of: a minimum pain level of 50 using a 100-point VAS, and ODI of >30%, osteoporotic compression fracture(s) at 1 or 2 levels, presence of edema on MRI or a positive bone scan and informed consent. Exclusion criteria included greater than 70% collapse, canal compromise, neurologic deficit at the level(s) treated or tumors. Post-operative CT and radiographs were used to quantify leakage, changes in gross morphology and subsequent fractures.
Results. A total of 43 consecutive patients (81% female) were treated at our institution; 26 were randomized to treatment and 17 to control. A total of 62 fractures were treated, 40 with Cortoss (1.54 level per pat.), 22 wit hPMMA (1.29 level per pat.). The average age was 80 and 82 in the Cortoss and PMMA groups respectively. Both groups showed similar and significant clinical improvements in VAS and ODI scores out to 12 months. The average volume injected per vertebra for the Cortoss group was 2.4cc, which is almost 40% less than the average of 3.9cc per level for the PMMA group. Leakages occurred in a similar frequency in both groups and were all asymptomatic; no cardiac irregularities or pulmonary emboli were reported in any patient.
Conclusions. These clinical results from a single institution suggest that Cortoss constitutes a good alternative to PMMA in obtaining immediate pain relief with vertebroplasty. These results are consistent with those obtained in Europe. In our series the amount of material necessary to obtain a clinical benefit appears to be less for Cortoss than for PMMA, which potentially also translates in smaller leaks. These results will be to be confirmed by the analysis of the pooled results of all 256 patients, which is expected in 2008.