Patent ID: 7875046

Claim:
A surgical tool for removing a block of material from a body, the surgical tool comprising a tool head including: (a) an elongated support element having a direction of elongation and configured for insertion along a first slit parallel to said direction of elongation into the material of the body; (b) a first blade assembly including: (i) a pair of arms pivotally mounted relative to said support element so as to rotate about a first axis perpendicular to said direction of elongation, a plane passing through said support element parallel to both said direction of elongation and said first axis being referred to as a tool plane, and (ii) a first blade element pivotally mounted on said arms so as to be pivotable about a second axis parallel to, but displaced from, said first axis, said first blade element including a rear cutting edge, said first blade assembly assuming an insertion state in which said pair of arms and said first blade element are deployed substantially in said tool plane, and a deflected state in which said first blade element is deployed to cut rearward in a direction forming an acute angle with said tool plane; (c) a second blade element pivotally mounted relative to said support element so as to be pivotable about a third axis substantially parallel to said first axis, said second blade element assuming an initial state in which said second blade element is deployed substantially in said tool plane and being pivotable to an inclined state in which said second blade element is arranged to cut in a direction inclined to said tool plane; and (d) a mechanical actuation arrangement including a plurality of spring elements and configured to resiliently bias said first blade assembly from said insertion state to said deflected state and to resiliently bias said second blade element from said initial state to said inclined state.