A Robotic Diathermy System for Automated Capsulotomy

Abstract

Background: Cataracts are the leading cause of blindness and are treated surgically. Capsulotomy describes the opening of the lens capsule during this surgery and is most commonly performed by manual tearing, thermal cutting, or laser ablation. This work focuses on the development of a flexible instrument for high precision capsulotomy, whose motion is controlled by a hybrid mechanical-magnetic actuation system. Methods: A flexible instrument with a magnetic tip was directed along a circular path with a hybrid mechanical-magnetic actuation system. The system’s motion control and thermal cutting behavior were tested on ex vivo porcine lenses. Results: Position control of the magnetic tip on a circular path with radius of 2.9mm resulted in a relative positioning error of 3% at a motion period of 60s. The instrument’s accuracy improves with decreasing speed. A fully automated capsulotomy is achieved on an ex vivo porcine lens capsule by continuously coagulating the tissue under controlled conditions. Conclus...