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.

A parallel robot to assist vitreoretinal surgery.

PURPOSE: This paper describes the development and evaluation of a parallel prototype robot for vitreoretinal surgery where physiological hand tremor limits performance. METHODS: The manipulator was specifically designed to meet requirements such as size, precision, and sterilization; this has six-degree-of-freedom parallel architecture and provides positioning accuracy with micrometer resolution within the eye. The manipulator is controlled by an operator with a "master manipulator" consisting of multiple joints. RESULTS: Results of the in vitro experiments revealed that when compared to the manual procedure, a higher stability and accuracy of tool positioning could be achieved using the prototype robot. CONCLUSIONS: This microsurgical system that we have developed has superior operability as compared to traditional manual procedure and has sufficient potential to be used clinically for vitreoretinal surgery.

Robot-assisted vitreoretinal surgery: development of a prototype and feasibility studies in an animal model.

PURPOSE: To develop a prototype robotic system designed to assist vitreoretinal surgery and to evaluate its accuracy and maneuverability. DESIGN: Experimental study. PARTICIPANTS: This study used harvested porcine eyes. METHODS: After development of a prototype robotic system, pointing accuracy tests of the system were performed on graph paper and in harvested porcine eyes. The average maximal deviation from the aiming point to the actual position of the tip of the instrument was compared between manually conducted procedures and those conducted with robotic assistance. The feasibility of creating posterior vitreous detachment (PVD), retinal vessel sheathotomy (RVS), and retinal vessel microcannulation also were evaluated in porcine eye models, and the success rates of 4 consecutive attempts for each kind of procedure were evaluated. MAIN OUTCOME MEASURES: The average maximum deviation in pointing accuracy tests both on graph paper and in animal eye models was a main outcome measure. The success rate of making PVD, RVS, and retinal vessel microcannulation was the other primary outcome measure. RESULTS: The pointing accuracy was superior with robotic assistance both on graph paper (327.0 microm vs. 32.3 microm) and in animal eye models (140.8 microm vs. 33.5 microm). Creating PVD, RVS, and retinal vessel microcannulation was feasible in 4 of 4 attempts, 4 of 4 attempts, and 2 of 4 attempts, respectively. The 2 failures in microcannulation were considered to be the result of difficulty in visual differentiation between the retinal vessel and retina in harvested porcine eyes. CONCLUSIONS: Improved accuracy and desirable feasibility of a prototype robotic system to assist vitreoretinal surgery were shown in this study. Research for wider implementation of robot-assisted surgery should be continued; there are some hurdles to overcome.