Characterization of polyurethane-based synthetic vertebrae for spinal cement augmentation training
M. Hollensteiner, M. Botzenmayer, D. Fürst, M. Winkler, P. Augat, S. Sandriesser, F. Schrödl, B. Esterer, S. Gabauer, K. Püschel, A. Schrempf - Characterization of polyurethane-based synthetic vertebrae for spinal cement augmentation training - Journal of Materials Science: Materials in Medicine, Vol. 29, No. 10, 2018
Purpose: Vertebral augmentation techniques are used to stabilize impacted vertebrae. To minimize intraoperative risks, a solid education of surgeons is desirable. To improve education of surgeons as well as patient safety, the development of a high fidelity simulator for the surgical training of cement augmentation techniques was initiated. The integrated artificial vertebrae should be able to provide realistic haptics during all procedural steps. Therefore, three different artificial vertebrae were developed, tested and validated with reference to human vertebrae. As a further reference, commercially available vertebrae surrogates for orthopedic testing were investigated.
Methods: To validate the new artificial vertebrae, three characteristic mechanical parameters for tool insertion force, namely weighting factors, cutting and clamping forces, were examined. Further, the balloon dilation pressure and volume were analyzed. Fluoroscopy images were taken to evaluate the bone cement distribution to validate the new vertebra surrogates against human vertebrae.
Results: Based on the measurement results, one group of artificial vertebrae was able to reflect the characteristic parameters in comparison to human vertebrae. The weighting factors (19.7±4.1), the cutting (13.1±0.9N) and the clamping forces (1.5±0.2N) of the human reference were reflected by one bone surrogate (11.9±9.8, 24.3±3.9N, 2.4±1.0N, respectively). The investigated balloon dilation pressure (13.0±2.4bar) and volume (2.3±1.5ml) of the artificial vertebrae were in good accordance with the human reference (10.7±3.4 bar, 3.1±1.1ml). Cement application forces were also in good accordance whereas the cement distribution couldn´t be reproduced accurately.
Conclusion: Artificial vertebrae were developed that delivered authentic haptics during transpedicular instrument insertion, balloon tamp dilation and bone cement application, were validated. This new training tool will help to improves surgical education.