A 3D brain deformation model experiencing comparable surgical loads

During the past 10 years, the finite element method (FEM) has been successfully employed to model the neuroanatomy under varying load conditions. Loading conditions used in previous work can be predominantly separated into two categories. The first category concerns large accelerations of the head followed by a sharp deceleration or impact. The second category considers maladies of the brain such as edema and hydrocephalus. The authors' research is focused on creating a third category which involves the application of surgical loads. In neurosurgical procedures, various instruments are used which purposely retract/resect or inadvertently move tissue. In addition, other sources of brain shift include reduction in brain buoyancy due to cerebrospinal fluid (CSF) drainage and administered drugs such as mannitol which causes brain volume to decrease by transporting fluid away from the tissue via the brain vasculature. The concern is that intraoperative loads such as these will move designated subsurface operative areas and lead to surgical error. The ultimate goal of the authors' research is to model surgical loads, predict subsequent deformation and update the surgeon's navigation fields in real time. However, the scope of this paper is limited to the development of an initial 3D model of brain deformation.