Feasibility study on robot-assisted retinal vascular bypass surgery in an ex vivo porcine model.

PURPOSE: To describe a new robot-assisted surgical system for retinal vascular bypass surgery (RVBS) and to compare the success rate with freehand RVBS.

METHODS: A robot-assisted system for retinal microsurgery was constructed to include two independent robotic arms. A 23-gauge light probe and an intraocular forceps were affixed to the arm end effectors to perform the intraocular manipulation. Harvested porcine eyes were introduced to be established animal models of closed-sky eyeballs after that pars plana vitrectomy using temporary keratoprosthesis was performed by a skilful surgeon. Retinal vascular bypass surgery (RVBS) was performed by an inexperienced ophthalmologist to test the ease of use. A stainless steel wire (45-μm pipe diameter) was used as an artificial vessel. Before RVBS, the wires were prepositioned at the retinal surface of the eyes. The Control group (n = 20) underwent freehand RVBS, and the Experimental group (n = 20) underwent robot-assisted RVBS. To create the simulated bypass, the distal end of the wire was inserted into the selected vessel and advanced ~4 mm away from the optic disc. If successful, then the proximal wire end was inserted and advanced ~2 mm towards the optic disc. The difference in the success rate for the freehand and robot-assisted procedures was analysed by the chi-square test.

RESULTS: The success rate for the freehand RVBS was 5% (1/20 eyes). In contrast, the robot-assisted success rate was 35% (7/20) of eyes (p < 0.05).

CONCLUSION: This study demonstrated the feasibility of robot-assisted RVBS in ex vivo porcine eyes. The robotic system increased the accuracy and stability of manipulation by eliminating freehand tremor, leading to a higher surgical success rate.