Patent ID: 9072559
Filing Date: 2015-07-07
Classification: A61B,B21K

Abstract:
1. An adjustable length bone screw for use in a surgical operation where the screw is inserted into a bone, the bone screw comprising: a screw head extending between a proximal end and a distal end and having an outer surface, and a shaft, the screw head and the shaft extending along a longitudinal axis, the shaft having a shaft outer surface and extending between the distal end of the screw head and a distal tip, wherein the outer surface of the screw head has a maximum diameter measured along a first direction that is perpendicular to the longitudinal axis that is greater than a maximum diameter of the shaft outer surface measured along the first direction; a plurality of threaded portions located at discrete positions longitudinally along the shaft, and a plurality of unthreaded portions located at discrete positions longitudinally along the shaft, wherein the threaded portions are separated longitudinally by the unthreaded portions, and wherein the threaded portions contain a series of threads extending at least partially circumferentially around the shaft; wherein the plurality of the threaded portions each have at least two cutting flutes each defined by a notch formed radially into the screw shaft and extending longitudinally along the length of the threaded portions such that the threads of the threaded portions are formed into at least two discontinuous thread segments extending circumferentially around the shaft, and wherein a plurality of the unthreaded portions are tapered along the shaft longitudinally in a proximal to distal direction and a plurality of the threaded portions proximally adjacent to the plurality of tapered unthreaded portions contain at least one thread that is tapered in the same angle as the taper for the adjacent unthreaded portion.