Abstract: A surgical instrument includes an elongated member connected to both a suction device for removing excised tissues and fluids and to a source of pressurized fluid. The member has an inner and outer wall with a hollow lumen extending the length of the member which connects a variably shaped ostium, extending through both walls of the member, to the suction means. The member also has peripheral channels extending the length of the member which connect the fluid source to the ostium through slits in the perimeter of the ostial wall. The slits collectively extend almost the full perimeter of the ostial wall. The slits are preferably designed so that as pressurized fluid is ejected from any point along a slit across the ostium, the fluid will come in contact with an opposing spray of fluid ejected from an opposing point in an opposing slit.