Adjustable intra-liminal valvulotome

Claim 1

An adjustable intraluminal valvulotome comprising: a hollow tubular member having a distal end and a proximal end; first and second substantially identical, opposed cutting blades movable between an extended position and a retracted position with respect to said distal end of said tubular member and between an open position in which said cutting blades are spaced apart from each other and a closed position in which said cutting blades are drawn tightly against each other, said cutting blades being in said closed position when in said retracted position and in said open position when in said extended position, each of said cutting blades having a complex concave inner surface, a complex convex outer surface, a forward blunt edge in the direction of extension, a rearward cutting edge in the direction of retraction, and a pair of opposed side edges, one of said side edges being a blunt edge and the other of said side edges being a cutting edge, said inner surfaces of said cutting blades substantially facing each other in all said positions and said forward blunt edges meeting when said cutting blades are in said closed and retracted positions; control means slidably disposed within said hollow tubular member for moving said first and second cutting blades between said extended and retracted positions and a plurality of partially-extended positions intermediate said extended and retracted positions; spacing means for moving said first and second cutting blades laterally apart from each other from said closed position to said open position as said control means moves said cutting blades from said retracted position to said extended position; and shielding means for shielding at least said rearward cutting edges of said first and second cutting blades in said retracted and closed positions.