Patent ID: 8864766

Claim:
A Kerrison-type rongeur, comprising: an elongate chassis having at a proximal end, a handle assembly for gripping by an operator and at a distal end and a footplate protruding therefrom, said footplate having a surface forming a first angle from vertical and comprising a first cutting element, said first cutting element comprising a first perimeter raised around at least a portion of said surface forming a recess therein, said first perimeter comprising a first beveled surface tapered to form a first blade at an outer surface of said first perimeter and a second beveled surface tapered to form a second blade at an inner surface of said first perimeter; and an elongate upper member slideably affixed to said chassis and engaged at a first end to said handle assembly so as to be advanceable to said footplate by operation of said handle assembly, said upper member further comprising a second cutting element at a second end, said cutting element forming a second angle from vertical that is different from the first angle of said footplate surface, said second cutting element comprising a second perimeter raised around a least of portion of said second end, said second perimeter comprising a third beveled surface tapered to form a third blade at an outer surface of said second perimeter and a fourth beveled surface tapered to form a fourth blade at an inner surface of said second perimeter; wherein said second cutting element is advanced closely past said first cutting element by operation of said handle assembly such that tissue situated between said cutting elements is resected by a shearing action between said cutting elements, said first blade passing inside said fourth blade and being received within said recess to produce a portion of said shearing action and said second blade passing outside of said third blade to produce a portion of said shearing action.