Radiofrequency-targeted vertebral augmentation versus traditional balloon kyphoplasty: radiographic and morphologic outcomes of an ex vivo biomechanical pilot study

Brian E Dalton,¹ Andrew C Kohm,2 Larry E Miller,^3,4 Jon E Block,⁴ Robert D Poser<sup>2

1</sup>Tri-State Neurological Surgeons, Erie, PA, ²DFINE, Inc, San Jose, CA, ³Miller Scientific Consulting, Inc, Arden, NC, ⁴The Jon Block Group, San Francisco, CA, USA

Purpose: Traditional balloon kyphoplasty (BK) is a common treatment for symptomatic vertebral compression fractures. The purpose of this study was to compare a novel vertebral augmentation technique, radiofrequency-targeted vertebral augmentation (RF-TVA), to BK for restoration of vertebral height, cavity creation, and polymethylmethacrylate (PMMA) delivery and interdigitation into the surrounding trabeculae.
Methods: This ex vivo biomechanical pilot study utilized 16 osteoporotic cadaveric vertebral bodies in a standardized fracture model to compare unipedicular RF-TVA (n = 8) to bipedicular BK (n = 8). Four specimens from each group were tested in loaded and unloaded conditions. All specimens were imaged, assessed for height restoration, and sectioned to observe PMMA distribution. A subset of specimens underwent computed tomography scanning to assess cavity creation and trabecular architecture prior to cement delivery.
Results: Anterior height restoration was greater with RF-TVA (median: 84%, interquartile range: 62%–95%) compared to BK (median: 69%, interquartile range: 60%–81%), although the difference did not achieve statistical significance (P = 0.16). Anterior height restoration was numerically greater under loaded (median: 70% versus 66%) and unloaded (median: 94% versus 77%) conditions with RF-TVA versus BK. RF-TVA produced more discrete cavities and less native trabecular destruction compared to marked trabecular destruction observed with BK. RF-TVA consistently showed a well-identified focal area of PMMA with an extensive peripheral zone of PMMA interdigitation, providing mechanical interlock into the adjacent intact trabecular matrix. In contrast, BK yielded little evidence of PMMA interdigitation beyond the boundaries created by the balloon tamp due to the crushed trabecular bone peripherally.
Conclusion: RF-TVA achieves favorable vertebral height restoration with targeted PMMA delivery and less trabecular destruction compared to BK. RF-TVA has potential clinical utility in the aging population with painful osteoporotic vertebral fracture.

Keywords: balloon kyphoplasty, fracture, polymethylmethacrylate, radiofrequency targeted, vertebral augmentation

Erratum for this paper has been published