A method for treating a body tissue comprises delivering a cutting mechanism of a surgical instrument into proximity to a target portion of the body tissue wherein the cutting mechanism includes a first member defining a lumen and a distal cutting tip. At least the first member is supported, via a coupler, by the handpiece. A fluid pathway extends from the distal cutting tip, through the lumen of the first member, and through an interior of the handpiece for fluid connection to a source of negative pressure. In one configuration, a coupler provides an internally-located aspiration control mechanism including a user interface port exteriorly exposed on the coupler and defining an aspiration control pathway extending from the user interface port to a proximal window of the inner member for communication with the lumen of the inner member. With the distal cutting tip placed into contact with the target portion, the treatment site is selectively aspirated by manipulating a position of a finger relative to the user interface port to manually effectuate an altering of a level of vacuum applied by the source of negative pressure at the distal cutting tip.