Foam phantom development for artificial vertebrae used for surgical training

Currently the surgical training of kyphoplasty and vertebroplasty is performed on patients or specimens. To improve patient safety, a project was initiated to develop an Augmented Reality simulator for the surgical training of these interventions. Artificial vertebral segments should be integrated to provide realistic haptic feedback. To reach this, resulting forces during needle insertions (trans- and extrapedicular) into formalin-fixed vertebral specimens were measured. The same insertion procedure was also performed on six customized polyurethane blocks with varying mechanical parameters. Based on the results of these measurements, a specific foam phantom was generated and the insertion force measured. Additionally a parametric model for the needle insertion into bone was designed calculating three characteristic parameters for all insertion measurements. The resulting insertion force for the foam phantom was comparable to the specimen measurements and the parametric model provided comprehensible characteristic parameters. Based on the resulting force during needle insertion into human vertebrae, a possible foam recipe for manufacturing artificial segments was found. Furthermore, the parametric model provides characteristic parameters for the assessment of phantoms as well as the development of its production process.