Mechanical response of brain to mechanical stimuli - animal model investigation

Background and purpose: Conventional neurosurgical procedures give surgeons both tactile and visual feedback. Unlike conventional procedures, minimally invasive surgery is devoid of haptic feedback. Incorporation of tactile feedback into neurosurgical robotic systems can greatly enhance the results of minimally invasive procedures. Hence, the ultimate goal of the research presented here is to define the force response of the brain to different types of mechanical stimuli (short- and long-term). The experimental results describe the force responses of brain during idnentation tests. Material and methods: Seven ovine head specimens with exposed brain were fixed to an MTS Synergic 100 testing machine using a rigid clamp - metallic frame with sharp-end screws. Four regions were loaded by a hemispherically-ended cylindrical indentor. Each of the indentations applied to the brain was divided into two general stages: insertion and hold which was constant for 180 s. Measurements for the following 3 loading velocities were conducted. The force response of brain to mechanical stimulus was acquired for each case. Results: The force response of brain to short-term mechanical stimulus depend on both loading velocities and regions of indentation, whereas the long-term force response depends on the history of loadings. Conclusions: The development of minimally invasive neurosurgica systems requires estimation of the mechanical response of brain to contat with surgical devices. For this reason, investigation of the force response of brain employing different boundary conditions is necessary.