Development of a haptic feedback model for computer simulation of the epidural anesthesia needle insertion procedure

The main focus of the research was to create realistic feeling force-feedback models for a virtual-reality computer simulation of the epidural needle insertion procedure. The epidural needle insertion procedure is a common procedure in which the anesthesiologist inserts a needle into the spinal region of the back. During this procedure, the anesthesiologist relies heavily on perception of force from the needle in order to visualize the tissue layers being penetrated.; The motivation for, and initial development of, a virtual reality simulator for the epidural needle insertion procedure is presented. A user study in which anesthesiologists used the initial simulator and qualitatively scored it's performance is presented. The results of this study indicated that the force-feedback models in the initial simulator did not feel realistic.; A force modeling methodology has been developed in which biomaterials testing was done to measure load displacement curves as needles were inserted into biological specimens. High resolution MRI scans were performed prior to the biomaterials testing and registered to the needle insertion locations in order to identify each layer the needle punctured.; Force models were developed for each type of tissue punctured during the epidural needle insertion procedure. These models were combined to create a generalized force model for the procedure. Force models were also developed for needle insertion into oranges.; Two virtual patients were developed from MRI data sets of two human subjects, an average female and a lean male. Four virtual oranges were also developed. A haptics-only computer simulator was developed which used a prototype force-feedback device on loan from Immersion Corporation.; The virtual oranges were used in a study to test the realism of force models developed through the force model development methodology. Two user studies were performed in which subjects directly compared needle puncture into physical oranges and virtual oranges in a blind randomized trial. The results of these studies indicate that the subjects could not differentiate between the physical and the virtual oranges.; A user study was planned to test for construct validity of the epidural simulator. Limitations of the hardware made this study infeasible, but the study did provide insight into future development issues.