Surgical tool for coring precise holes and providing for retrieval of tissue

A surgical tool assembly comprising:

• a sleeve having an open end adapted for removable placement proximate to a tissue wall of a patient;
• a bladed member including a cylindrical portion defining an open end, a cone portion defining a closed end, and an opening extending therebetween, the bladed member being a cup having a cutting edge of a predetermined shape surrounding the opening, the bladed member being removably mounted on a slidable shaft for movement back and forth along a longitudinal axis of the sleeve from within the open end of the sleeve to an axially extended position outwardly from the open end of said sleeve, the cutting edge facing the open end of the sleeve when extended, the bladed member being extendable to traverse the tissue wall in one direction without any portion of the surgical tool cutting the tissue wall and retractable in the opposite direction toward the sleeve whereby the cutting edge severs a portion of the tissue wall independently of the sleeve and the bladed member retains the severed portion within the cup to form an opening in the tissue wall having said predetermined shape;
• a sewing ring configured to be attached to the tissue wall;
• and
• an interface comprising a ridge that extends from and surrounds a distalmost portion of a distal end of the open end of the sleeve, the ridge having a surface configured to mate with an interior surface of the sewing ring to orient the slidable shaft relative to the tissue wall and to center the ridge over the sewing ring.