Kanako Harada

Integration of a Miniaturised Triaxial Force Sensor in a Minimally Invasive Surgical Tool

This paper reports preliminary results on design and fabrication of a cutting tool with an integrated triaxial force sensor to be applied in fetal surgery procedures. The outer diameter of the proposed device is 7.4 mm, but a scaled down design can be easily achieved. Linearity and hysteresis tests have been performed for both normal and tangential loadings. A linear transformation relating the sensor output to the external applied force is introduced and discussed. The typical working range for the conceived instrument is around 0.3 N, while 20 N and 1 N are, respectively, maximum normal and tangential forces for which the device robustness has been assessed

Master–slave robotic platform and its feasibility study for micro‐neurosurgery

Microsurgery is a widely performed process in neurosurgery. However, it is difficult for surgeons because manipulating small and long instruments under a microscope often restricts dexterity. Hand tremors are also an issue, as the accuracy required for microsurgery is very high.

Design of a Robotic Module for Autonomous Exploration and Multimode Locomotion

The mechanical design of a novel robotic module for a self-reconfigurable modular robotic system is presented in this paper. The robotic module, named Scout robot, was designed to serve both as a fully sensorized autonomous miniaturized robot for exploration in unstructured environments and as a module of a larger robotic organism. The Scout robot has a quasi-cubic shape of 105 mm × 105 mm × 123.5 mm, and weighs less than 1 kg. It is provided with tracks for 2-D locomotion and with two rotational DoFs for reconfiguration and macrolocomotion when assembled in a modular structure. A laser sensor was incorporated to measure the distance and relative angle to an object, and image-guided locomotion was successfully demonstrated. In addition, five Scout robot prototypes were fabricated, and multimodal locomotion of assembled robots was demonstrated.

ICG fluorescence endoscope for visualization of the placental vascular network

Intrauterine laser photocoagulation for twin-twin transfusion syndrome (TTTS) needs accurate in-situ recognition of placental vascular anastomosis. Because the conventional procedure is highly dependent upon the operators’ skill and experience, we developed a new way to visualize the placental vascular network by a rigid-type fluorescence endoscope coupled with intravenous administration of Indocyanine green (ICG). The feasibility of the fluorescence endoscope was examined with monkey placentas and pregnant rats. The ICG fluorescence endoscope can visualize the placental vascular network in detail even in the presence of turbid amniotic fluid. Thus, this method is potentially useful for in-situ definition of the placental vascular anastomoses during the treatment for TTTS. In addition, our rigid-type fluorescence endoscope will also be a useful tool for lymph node dissection using ICG by endoscopic surgery.

Robust Visual Tracking of Robotic Forceps Under a Microscope Using Kinematic Data Fusion

Forceps tracking is an important element of high-level surgical assistance such as visual servoing and motion analysis. This paper describes a robust, efficient tracking algorithm capable of estimating the forceps tip position in an image space by fusing visual tracking data with kinematic information. In visual tracking, the full-state parameters of forceps are estimated using the projective contour models of a 3-D CAD model of the forceps. The likelihood of the contour model is measured using the distance transformation to enable fast calculation, and the particle filter estimates the full state of the forceps. For more robust tracking, the result data obtained from visual tracking are combined with kinematic data that are obtained by forward kinematics and hand-eye transformation. The fusion of visual and kinematic tracking data is performed using an adaptive Kalman filter, and the fused tracking enables the reinitialization of visual tracking parameters when a failure occurs. Experimental results indicate that the proposed method is accurate and robust to image noise, and forceps tracking was successfully carried out even when the forceps was out of view.

Assessing Microneurosurgical Skill with Medico-Engineering Technology

OBJECTIVES Most methods currently used to assess surgical skill are rather subjective or not adequate for microneurosurgery. Objective and quantitative microneurosurgical skill assessment systems that are capable of accurate measurements are necessary for the further development of microneurosurgery. METHODS Infrared optical motion tracking markers, an inertial measurement unit, and strain gauges were mounted on tweezers to measure many parameters related to instrument manipulation. We then recorded the activity of 23 neurosurgeons. The task completion time, tool path, and needle-gripping force were evaluated for three stitches made in an anastomosis of 0.7-mm artificial blood vessels. Videos of the activity were evaluated by three blinded expert surgeons. RESULTS Surgeons who had recently done many bypass procedures demonstrated better skills. These skilled surgeons performed the anastomosis with in a shorter time, with a shorter tool path, and with a lesser force when extracting the needle. CONCLUSIONS These results show the potential contribution of the system to microsurgical skill assessment. Quantitative and detailed analysis of surgical tasks helps surgeons better understand the key features of the required skills.

FORCE ANALYSIS OF ORTHOGONAL CUTTING OF BOVINE CORTICAL BONE

In orthopedic operations, no sound solutions exist to avoid conditions like tool breakage, bone fracture/cracks and thermal necrosis for lacking understanding of the mechanics of the bone cutting process. In this work, analysis of variance (ANOVA) and regression analysis were performed to investigate effects of cutting conditions on cutting and thrust forces based on a full factorial design. Then applicability of Merchants analysis for calculating cutting force with respect to rake angle and feed was evaluated by comparison with experiments. Finally, the friction coefficient was evaluated by calculation. ANOVA shows that forces are much more sensitive to feed, cutting direction and rake angle than to cutting speed. Regression equations including all four factors were obtained by introduction of dummy variables. Cutting forces from experiments and from Merchants analysis are partially comparable (maximum relative error = 34%) when feed and rake angle are changed. Friction coefficient was affected by rake angle and cutting direction. Cutting speed had little effect on the coefficient. These results can deepen the understanding of the mechanics of the bone-cutting process and assist the development of innovative cutting devices and selection of favorable cutting conditions for the procedure.

Microsurgical skill assessment: Toward skill-based surgical robotic control

A surgical skill assessment system was developed to quantify microsurgical skills. Infrared optical makers, an inertial measurement unit, and strain gauges were mounted on tweezers to record surgical tasks. In preliminary experiments, the tool tip trajectory, acceleration, and applied force were measured and microsurgery videos were evaluated by three expert surgeons. The preliminary results indicated the feasibility of the system by showing the significant difference between unskilled and skilled surgeons.

Quantitative assessment of manual and robotic microcannulation for eye surgery using new eye model

Microcannulation, a surgical procedure for the eye that requires drug injection into a 60–90 µm retinal vein, is difficult to perform manually. Robotic assistance has been proposed; however, its effectiveness in comparison to manual operation has not been quantified.

Electromagnetic drive of microrobot geometrically constrained in blood vessel

We propose new electromagnetic actuation of a microrobot by utilizing geometric constraints in a blood vessel. In our concept, a microrobot travels in a vascular network while keeping the contact to the vascular wall. In the paper, forces working on the microrobot are modeled in two dimensions, and conditions to propel the microrobot while pushing it against the vascular wall are described. The design of the microrobot composed of three permanent magnets is also presented. The feasibility of the 2D actuation of the microrobot was confirmed using an experimental setup composed of four pairs of coils generating both uniform magnetic fields and uniform magnetic field gradients. Finally, the model was extended to 3D in order to investigate 3D actuation of the microrobot.