Haptic interaction between a rigid instrument and soft tissues

Sometimes surgeons have to perform "blind surgery", relying on the sense of touch rather than vision. This is for instance the case in brain surgery, specifically when a thin elongated tube, a catheter, has to be penetrated inside the ventricles to remove the excess of cerebrospinal fluid in the brain. The forces acting on the catheter will vary according to the number of tissues present along the insertion path of the catheter. The resultant of these forces will be transmitted to the neurosurgeon's hand. Depending on the tissue penetrated by the catheter, an experienced neurosurgeon is able to tell which tissue is in contact with the catheter by using his/her sense of touch. This skill is essential, and novice neurosurgeons have to learn it at an early stage so that they may use it more efficiently in their daily work. By using Virtual Reality, it is possible to record parameters such as force and position in space and time, during simulation. Two studies are currently carried out. One of the studies is detecting the force profile sensed when penetrating a rigid instrument inside a tissue compared to a reference force profile. The second study is about piercing a membrane with a rigid instrument and investigates how fast neurosurgeons react on the piercing effect. For both studies, it is believed that when the human sensory-motor system executes complex tasks, it automatically tries to optimize performance by leaving as much as possible to subconscious control, while focusing consciously on the most important factor for successful performance. The results from the two studies in concert will allow creating a simple model of the sensory-motor system with optimal parameters for training inexperienced neurosurgeons.