Clinical Study

Clinical testing for the Ascendx VCF Repair System included a prospective and multicenter evaluation of 60 subjects treated with the Ascendx System and the Ascendx cement.  Outcomes evaluated included acute procedural success, pain, function, and adverse events including leakage and subsequent fractures. Follow-up was performed at discharge and 1, 3, 6, and 12 months post-treatment.  Results were compared to an investigation using the same cement without the Ascendx in 113 subjects, an investigation for 29 subjects undergoing treatment with the predicate device and 31 subjects undergoing vertebroplasty, and results for kyphoplasty procedures performed with the predicate device and PMMA cement that are published in literature.  

The effectiveness results compare favorably with results reported in the vertebral augmentation literature, a PMMA cement control study, and a kyphoplasty study conducted with a competitive device. Specifically, subjects treated with the Ascendx System experienced an average improvement in mean VAS pain score at 30 days of 50.52 mm (5.05 cm) compared to baseline, which compares well to the typical improvement noted in the medical literature of between 1.89 and 7 cm. The subjects treated with the Ascendx system had an average improvement in mean VAS at 12 months of 66mm.  In the cement study, VAS scores improved by 58mm at 30 days (1 month), and improved by 66.8mm at 12 months.  The competitive product study also had similar improved VAS scores over the twelve month follow-up.  At 30 days, VAS scores improved by 4.633cm and had improved by 4.433cm by 12 months as shown in the graph below.
For the Ascendx study, improvements in ODI scores at 30 days compared to baseline (31.17-point improvement) are also consistent with the literature, which reports a range from 19.5 points to 31.7 points, with most studies reporting improvement in the 20-30 point range.  The average improvement in mean ODI at 12 months was 45.22 points.  This also compares favorably with the competitive product study, in which there was an average improvement in mean ODI at 3 and 12 months of over 36 points as shown in the graph below.

Overall subject quality of life generally improved after treatment with the Ascendx VCF Repair System.  Specifically, considering the norm-based domain scores, in general the study population fell below the U.S. population mean of 50, as would be expected in an osteoporotic compression fracture population. Both the PCS and the MCS scores continually improved from baseline through the final follow-up timepoint at twelve months for patients who underwent VCF repair with the Ascendx VCF Repair System as shown in the table below.  Thus, by the conclusion of the study, subjects demonstrated MCS scores very similar to the overall U.S. population, although PCS scores were still notably below the U.S. population mean of 50.  However, this finding is consistent with the average age and prevalence of comorbid conditions in the study population. Therefore, the SF-36 results demonstrated overall improvement in health-related quality of life post-procedure.
In addition, the safety results for the Ascendx study compare favorably with results reported the vertebral augmentation literature, the cement study, and the competitive device study.  The investigator-reported cement extravasation in the Ascendx study was determined to be 16.7% of subjects, whereas published kyphoplasty studies have reported rates of 0-59%.  The cement study using the same cement had similar cement extravasation rates of 36.3%.  The competitive product study performing kyphoplasty using the predicate device also had similar cement extravasation rates of 31.0%.  
 
Adjacent fracture rates for the Ascendx IDE study were also within the ranges found in the literature for kyphoplasty and were similar when compared to the cement study. In the Ascendx study, there were 10 subjects (16.7%) with reported adjacent level fractures during the follow-up period. Comparatively, adjacent level fracture rates of 4-25% have been reported in the kyphoplasty literature.  The cement study had an adjacent fracture rate of 16.8%.  If these rates are adjusted for the number of subjects who returned at the 12-month follow-up visit, the Ascendx IDE had 20.1% (10/49) adjacent level fractures compared to 20.2% (19/94) fracture rate for the cement study cohort.
 
Improvement in pain, function and quality of life was significant after treatment with the Ascendx VCF Repair System, while complications were minimal.