A surgical instrument (22) including a coupler (33) maintaining an inner (54)and outer (52) members to define acutting implement (30)； and an aspiration control pathway between a first port(35) exposed at an exterior of the coupler (33) anda second port (103) connectable to a source of negative pressure (24) via. alumen (105) of the Inner member (56), wherein theaspiration control mechanism provides user control over the level of vacuumapplied at the cutting tip implement via selectivepositioning or a finger over the first port (35).
