Naohiko Sugita

Impact of network time-delay and force feedback on tele-surgery

ObjectWe have developed a robotic minimally invasive surgical system within a tele-surgery capability and conducted several times of tele-surgery experiments including Japan–Thailand and Japan–Korea tele-surgery experiments by using conventional network infrastructures. In these experiments, laparoscopic cholecystectomies have been successfully performed on pigs. On the other hand, repetitive task evaluation studies are also crucial for further studies on tele-surgery applications. Nowadays, task evaluations of tele-robotic system within network time-delay have been studied in past years by many researchers. These experiments have been mostly focused on simplified tasks such as a peg-in-hole task. However, most of surgical procedures in minimally invasive surgery are based on medical specific skills such as anatomical knowledge and past experiences of surgeons. From these perspectives, a trial experiment within two tasks including surgery oriented manipulations was conducted to study the impact of network time-delay and force feedback on tele-surgery.Materials and methodsThe experiment was conducted by using the minimally invasive surgical system. As the experimental setup, a research and development Internet, JGN2 (Japan Gigabit Network 2) was used as a network infrastructure, and two tasks were performed by 15 subjects including 5 medical doctors. The trial conditions were given by changing time-delay (on the both tasks) and force feedback (on the first task). The first task was configured to test a simple surgical procedure, which is commonly performed in a laparoscopy as translational motions of surgical tools. The subjects were instructed to touch four columns located on points of a square. The second task was configured to test integrated surgical procedures. The subjects were instructed to perform a part of suturing procedures by using the robotic bending forceps.ResultsIn the first task, the completion time was increased approximately 50% by time-delay. By using force feedback, the applied force was decreased. However, the effectiveness of force feedback was not strongly shown in MD group. On the other hand, the effectiveness of the force feedback was strongly shown in the applied force on the tip of surgical tool in both MD and non-MD groups. In the second task, the adverse impact of time-delay was not strongly shown in MD group. From the analysis of the motion records found that a skill of experienced surgeons on “occlusion problem” could be related in the results. These results indicate that skilful operators on surgical procedures can overcome the adverse impact of time-delay by introducing their skills depending on required surgical tasks. However, the drawback of time-delay still remains concerning on safety issues. The effectiveness of the force feedback was strongly shown in the first task in terms of the applied force on the surrounding environment.ConclusionsForce feedback is an essential technology for further applications of tele-surgery. In addition, the force feedback technology can be partially used for compensating the drawback of time-delay.

Simultaneous measurement of surface profile and thickness variation of transparent parallel plate using wavelength tuning Fizeau interferometer

In this study, a 6N – 5 phase shifting algorithm comprising a polynomial window function and discrete Fourier transform is developed for the simultaneous measurement of the surface shape and optical thickness of a transparent plate. The characteristics of the 6N – 5 algorithm were estimated by connection with the Fourier representation. The phase error of the measurements performed using the 6N – 5 algorithm is discussed and compared with those of measurements obtained using other algorithms. Finally, the surface shape and optical thickness of a transparent plate were measured simultaneously using the 6N – 5 algorithm and a wavelength tuning interferometer.

1P1-E02 Fabrication of retinal vessel model with curved surface structure

Vein of the retina being closed is called retinal vein occlusion. As a new treatment for retinal vein occlusion, microcannulation has been used in eye surgery. Microcannulation is a treatment to approach the fundus by inserting a micropipette from the surface of the eye, injecting directly thrombolytic drugs to the retinal vein being occluded. Because microcannulation is very difficult surgery even for the experienced doctors, robotic system for vitretinal surgery has been developed. However, evaluation and training system is not well developed. Therefore, we propose the microvessel model with a circular cross-section and a curved surface structure for evaluation of some microsurgical robotic systems to assistant vitreoretinal surgery and training for doctors.