Laparoscopy and catheters have popularized minimally invasive surgery (MIS), require microscopic tools. Two types of microforceps we designed using a minimum number of parts uses metal injection molding (MTM) or laser processing to realize strong mass production. Microforceps installed in the tip of a catheter. Stress analysis verified its capability to grasp, bend and turn within the confines of a blood vessels model.
This paper proposes a force visualization mechanism for endoscopic surgical instruments using Moire fringe. This mechanism can display fringes or characters that correspond to the magnitude of a force between the surgical instruments and internal organs without the use of electronic elements, such as amplifiers and strain gauges. It consists of an elastic element and two films printed with grating and can be built in the surgical instruments. The structure is simple, and its fabrication is inexpensive. We developed a forceps with the mechanism and experimentally verified that it can display the magnitude of the grasp force. We also verified that its display is visible through an endoscope at in vivo pig experiment.
To secure the appropriate workspace in the brain for new robotic neurosurgery, we are developing the Workspace-creation manipulator system based on 2N type tendon control. The manipulator joint is controlled by two methods to avoid excess retraction to the brain. One is the wire elasticity compensation angle control that doesn't give organs too much displacement and the other is the joint torque control that achieves retraction in minimum pressure using organ stress relaxation. The basic performances of the two methods were performed, wire elasticity compensation angle control had 3 deg accuracy and joint torque control had 0.1 Nmm accuracy. To confirm the effectiveness of the manipulator control methods, we did in vitro experiment using pig brain. The result shows no excess displacement or pressure during retraction by these two methods.
The progress of the intraoperative imaging technology has had dramatic impact on brain tumor surgery. Intraoperative MRI (iMRI) with a navigation system has been used for brain tumor removal at Nagoya University Hospital. Restore-registration method is one of the registration methods using iMRI, performs the registration by using preoperative registration and image fusion information. Although the accuracy of navigation system strongly influenced on registration method, the accuracy of restore registration fell low occasionally. The purpose of this study was to improve the navigation accuracy using intraoperative re-registration with newly developed registration arm, set easily on the headframe. It enable update the registration information. The accuracy of re-registration with the registration arm was superior than that of Restore-registration method (without using the registration arm). In conclusion, improvements of navigation accuracy were confirmed to compare between the restore registration and the re-registration.