Realistic deformable models for simulating the tongue during laryngoscopy

During the procedure of laryngoscopy, an anaesthetist uses a rigid blade to displace and compress the tongue of the patient, and then inserts a tube into the larynx to allow controlled ventilation of the lungs during an operation. This procedure can sometimes be difficult and even life threatening, and there is therefore a need for regular training. Currently, plastic models are used for this purpose, and these have many disadvantages. Computer simulation is an attractive alternative, however, for proper realism it is necessary to build a model of the upper airway. In particular, we need a deformable model that can realistically simulate the behaviour of the tongue as it is compressed by the blade. We start from medical images, extract the details that characterise the subject and then incorporate these in a finite element model to investigate how the tongue tissue behaves in response to the insertion of the blade, when it is subjected to a variety of loading conditions. The results show that, within a specific set of tongue material parameters, the simulated outcome can be successfully related to the experimental laryngoscopic studies. Further research is underway to apply these results in a virtual reality simulation for laryngoscopic training. One main problem to be solved is computing the deformations in real time.