| 摘要 |
<p>Apparatus for the excision and removal of tissue, such as the lens of the eye includes a pencil-like handpiece (11) having a cannula probe (18) extending from the distal end thereof. The probe includes an inner jet tube (19) to direct a high pressure jet of fluid toward a tissue target, and an outer concentric aspiration tube (21) to aspirate and remove fluid and tissue. The jet tube is recessed proximally within the concentric aspiration tube, and the aspiration tube has an end area significantly larger than the end area of the jet tube. These factors cooperate so that the negative pressure exerted by the aspiration tube creates a suction force that offsets and exceeds the force of the fluid jet. The jet tube is connected to a fluid pressure system including a positive displacement pump (32), a pressure regulator (33), safety release (34), control valve (36), and a pulse former (37). The jet tube emits pulses of high pressure fluid that impinge reiteratively on the target, creating shock waves that fracture and emulsify the lens tissue, and the fluid also acts as a solvent to transport the emulsified tissue into the aspiration tube. The handpiece also includes a vacuum bypass port disposed to be selectively occluded by a finger of the surgeon, so that vacuum pressure may be released immediately when needed. <IMAGE></p> |
