Haptic Training Simulator for Pedicle Screw Insertion in Scoliosis Surgery
Pedicle screw insertion is a popular treatment for fixing spinal deformities in idiopathic scoliosis. A vital step in this free hand technique is the use of a probe to make a channel through the vertebrae pedicle. This is a sensitive process which carries risk of serious complications such as mechanical, neurological and vascular issues. Surgeons, who in the free hand technique are guided through this step dominantly by haptic feedback, are currently trained using cadavers or live patients. Cadavers often have vertebrae that are softer than real surgeons would typically encounter, while training on live patients carries the obvious issue of increased risk of complications to the patient.
In this thesis research, a haptic training device is developed that simulates haptic sensations that a surgeon would feel in this surgery. Creating a pathway through the pedicle by the free-hand technique is composed of two main degrees of freedom: rotation and linear progression. The rotary stage of the device which was developed by a previous student, is improved and extended in this research by adding proper hardware, designing a haptic model and proposing techniques to couple this with the linear degree of freedom. Haptic model parameters are then clinically tuned within a user study. Over ten surgeons of varying experience levels used the simulator to set a normal bone density and were able to change various parameters in order to tune the simulator to what felt most realistic. The surgeons were also asked to rate whether they believed the simulation to be a close representation of using a probe on an actual vertebrae, and whether they believed the simulation could be used in teaching. Statistical analysis is carried out on the gathered data to examine the research hypotheses. The results indicates the feasibility of the simulator to be used for the surgical education.