On dynamic videofluoroscopic swallow (VF) examination in dysphagic patients, posterior leak of the test material into the pharynx is often seen before the swallowing reflex starts. And this phenomenon sometimes caused aspiration. To prevent such aspiration, compensatory postures and changed food viscosity have been tested during the sequence of VF examination. However, there was not enough information about adequate application of these compensatory strategies (changes in food viscosity and patient's head posture) to dysphagic patients with posterior leak.
Thus, we designed a VF simulation system to study the flow velocity of food at the posterior leak using a lifesize oral-pharyngeal plaster model based on CT image data as a phantom.
As a result, VF simulation images that facilitate evaluation of the flow velocity of the test material (barium) leaking into the pharynx of oral-pharyngeal model were obtained. The flow velocity of the test material was decreased using a food thickening agent to increase the viscosity of the barium. When the oral-pharyngeal model was set in a head position with posterior tilting of thirty degrees, the flow velocity of the fluid test material was increased.
The data from this simulation might facilitate estimation of the optimal food viscosity and feeding position that would allow such patients to eat without aspiration.
