Medical instrument for removing bone

Claim 1

A medical instrument for cutting and removing bone comprising: a stationary tubular barrel member having a proximal end and distal end, wherein said distal end comprises a first working area, said first working area including a first cutting surface and a first stop surface, said first cutting surface and said first stop surface formed on opposite sides of the perimeter of said distal end wherein both said surfaces lie within a first plane substantially perpendicular to the axis of said tubular member, a solid cylindrical shaft member positioned coaxially within said barrel and arranged for reciprocal motion therein, said shaft member having a distal end and a proximal end, including a recess formed adjacent said distal end, said shaft member further comprising a plate member having a perimeter which is sized to substantially mate with the circumference of said barrel member to close said barrel member when said shaft member is reciprocated into said barrel, said plate member having a second work area, said second work area comprising a second cutting surface and a second stop surface, said second cutting surface and said second stop surface on the proximal face of said plate member formed on opposite sides of the perimeter thereof, said second cutting surface being formed by a concavity in the proximal face of said plate member such that both said second plane perpendicular to the axis of said shaft member, said first plane and said second plane being substantially parallel such that said first and second stop surfaces are in face confronting relationship and make full contact when said slidable shaft member is reciprocated to its full extent with respect to said barrel member, said full contact stopping the extent of reciprocation of said shaft member such that said first and second cutting surfaces are disposed in a cutting relationship while substantially avoiding direct force contact when said slidable shaft member is reciprocated to its full extent within said barrel member, and a lever means attached to the proximal end of both said barrel member and said shaft member for reciprocally translating said slidable shaft member within said barrel member causing said second working area associated with said slidable shaft member to reciprocate with respect to said first working area associated with said barrel member, thereby biting and severing any said bone positioned in the recess between said first and second cutting surfaces and causing both said severed bone and said recess to reciprocate into said barrel thereby capturing bone severed by said cutting surfaces within said recess.