Co-axial tube surgical infusion/suction cutter tip

Claim 1

A surgical instrument comprising a first tube having at one end an end wall disposed in a plane substantially normal to the longitudinal axis of the first tube which end wall contains an aperture; a second tube disposed substantially coaxially within the first tube and having at one end an end wall disposed in a plane substantially normal to the longitudinal axis of the second tube which end wall is resiliently urged by resilient means into close juxtaposition with the end wall of the first tube; the end wall of said second tube containing an aperture; said apertures extending only in said end walls so that the side walls of said tubes are free of any apertures; means to enable the tubes to be rotated relative to one another about their common axis, the apertures in the end walls of the tubes each lying wholly within the plane of its associated end wall and the apertures being so placed in the end walls that they are moved into register and substantially completely out of register with one another as the tubes are rotated relative to one another; annular duct means defined between the first tube and the second tube discharging at said one ends of the tubes to direct a stream of a liquid to said one ends of the tubes; and duct means to connect the interior of the second tube to a source of suction, an edge portion of each aperture being sharpened such that the edge portions together form cooperating shearing blades as the apertures are moved out of register.