Blunt dissection is a surgical technique to expose structures or to separate tissue without cutting. This paper addresses an element fracture model to avoid instability in blunt dissection simulation for virtual brain surgery. Blunt dissection is modeled by finite element fracture in which elements are fractured when their stresses exceed a specified fracture stress. However if an element is fractured without any consideration for connections with adjacent elements, the fracture may produce some structurally unstable elements. The structurally unstable elements cause computational instability. In order to avoid this instability problem, an element fracture model is proposed. The model is verified by comparing the results of blunt dissection simulation including the model with the results of the simulation without the model.
