Clinical results of an open prospective study of a bis-GMA composite in percutaneous vertebral augmentation

In this open prospective trial, 53 patients with acute pain from osteoporotic vertebral fracture related to osteoporosis or malignancy underwent vertebral augmentation with a new bisphenol-a-glycidyl dimethacrylate (bis-GMA) resin (Cortoss, Orthovita, Malvern, Pa, USA). Treatment consisted of up to 8 ml of Cortoss injected into a given vertebra. The procedure encompassed single and multiple injections (including the contralateral hemivertebra, to a maximum of 3 vertebral levels). Follow-up was at 4 and 8 days and at 1, 3, and 6 months. The primary efficacy end point was patient-rated pain using a 100-point visual analog scale (VAS, with 100 as severest pain) on day 4 following treatment; secondary end points were analgesic use and quality-of-life and disability scores from the Oswestry Disability Index (ODI) and a short-form 12-item questionnaire (SF-12). The present report contains interim results collected up to the 1-month post-treatment time point. At baseline, the group's mean VAS score was 69, indicating moderate to severe pain; at day 4, 32 of 53 patients (60.4%) reported a 30% or greater reduction in baseline pain accompanied by a VAS pain score less than 50 (mean 38.1). Pain reduction was maintained at 1 month (mean VAS 31.3). The average ODI score at baseline was 55, suggesting significant disability among participants prior to Cortoss treatment. Following treatment, the ODI scores were significantly reduced from these baseline levels (day 8, 47.4; 1 month, 33.6). Further, SF-12 physical and mental component scores at 1 month after treatment increased from baseline by 26% and 11%, respectively; while analgesic use decreased concomitantly, primarily among patients with underlying osteoporosis. A total of 20 adverse events were deemed to be device-related. The most frequent clinically significant adverse events attributed to Cortoss were leakage of Cortoss from within the vertebral body at placement (12%), back pain (7%), and unspecified pain (7%). These results indicate that vertebral augmentation with Cortoss rapidly reduces pain, decreases disability, and improves physical functioning in patients with painful vertebral compression fractures.