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

BACKGROUND: 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. METHODS: An eye model has been developed to quantify the performance of manual and robotic microcannulation. The eye model, which is implemented with a force sensor and microchannels, also simulates the mechanical constraints of the instrument's movement. Ten subjects performed microcannulation using the model, with and without robotic assistance. RESULTS: The results showed that the robotic assistance was useful for motion stability when the drug was injected, whereas its positioning accuracy offered no advantage. CONCLUSIONS: An eye model was used to quantitatively assess the robotic microcannulation performance in comparison to manual operation. This approach could be valid for a better evaluation of surgical robotic assistance.

Impact of robotic assistance on precision of vitreoretinal surgical procedures.

PURPOSE: To elucidate the merits of robotic application for vitreoretinal maneuver in comparison to conventional manual performance using an in-vitro eye model constructed for the present study. METHODS: Capability to accurately approach the target on the fundus, to stabilize the manipulator tip just above the fundus, and to perceive the contact of the manipulator tip with the fundus were tested. The accuracies were compared between the robotic and manual control, as well as between ophthalmologists and engineering students. RESULTS: In case of manual control, ophthalmologists were superior to engineering students in all the 3 test procedures. Robotic assistance significantly improved accuracy of all the test procedures performed by engineering students. For the ophthalmologists including a specialist of vitreoretinal surgery, robotic assistance enhanced the accuracy in the stabilization of manipulator tip (from 90.9 µm to 14.9 µm, P = 0.0006) and the perception of contact with the fundus (from 20.0 mN to 7.84 mN, P = 0.046), while robotic assistance did not improve pointing accuracy. CONCLUSIONS: It was confirmed that telerobotic assistance has a potential to significantly improve precision in vitreoretinal procedures in both experienced and inexperienced hands.

Microsurgical robotic system for vitreoretinal surgery.

PURPOSE: Robotics may improve vitreoretinal surgery by steadying hand motion, thereby reducing negative outcomes. This study aimed to develop a microsurgical robot for vitreoretinal surgery and to perform clinical procedures using robot-assisted interventions. METHODS: A microsurgical system for vitreoretinal surgery was designed to meet specific requirements for the degree of freedom, accuracy, and workspace. The system was intended to provide micrometer accurate manipulation within the eye. The slave manipulator has a tool change mechanism for switching surgical instruments. The slave manipulator is controlled by the surgeon using a master manipulator consisting of multiple joints. RESULTS: The robotic system was used to carry out microcannulation experiments on a pig's eye. A surgeon was able to successfully perform microcannulation. CONCLUSIONS: This microsurgical robotic vitreoretinal surgical system showed superior operability compared with a traditional manual procedure, and it demonstrated sufficient potential to warrant further testing in animal trials to assess its clinical feasibility.

Comparison of robot-assisted and manual retinal vessel microcannulation in an animal model.

AIM: To evaluate the performance of a parallel robotic system by comparison with the conventional manual procedure using an animal model. METHODS: A new parallel robotic system was developed that features a small cylindrical manipulator (base diameter 76 mm, height 240 mm). The performance of the new system was evaluated for its capability to assist in retinal vessel microcannulation. The test scenario was as follows: (1) introduce the microcannula into a harvested porcine eye attached loosely on the orbital fossa of an artificial face model through a 20G scleral port at the pars plana; (2) cannulate the retinal vessels (inner diameter 60-80 µm); and (3) inject indocyanine green dye into the eye endovascularly. The success rate and procedure quality of the robotic system were evaluated by comparison with the conventional manual procedure. RESULTS: Retinal vessel microcannulation and dye injection were achieved by the robotic system twice in four attempts, and by the conventional manual procedure either not at all or incompletely in all six attempts. Dye leakage was not observed with the robotic system, indicating that microcannulation was minimally invasive; in contrast, dye leakage was always observed with the manual procedure. CONCLUSIONS: The new system is more accurate than the conventional manual procedure for the tests on a porcine eye model.