Patent RU-2659017-C2 (RU)
Inventor: APPENTSELLER Andreas
IPC: A61B17/86
Filed: 2014-02-27
Granted: 2018-06-26
Abstract: FIELD: medicine. 
     SUBSTANCE: bone screw with adjustable length for use in a surgical operation, in which the screw is inserted into the bone, contains a screw head and a rod. Head of the screw extends from the proximal end to the distal end and has an outer surface. Screw head and the rod pass along the longitudinal axis. Stem has an outer surface of the stem and extends between the distal end of the screw head and the distal tip. Outer surface of the screw head has the largest diameter measured along the first direction perpendicular to the longitudinal axis, which is greater than the largest diameter of the outer surface of the rod measured along the first direction. Plurality of threaded portions are disposed at discrete positions along the rod and a plurality of non-threaded portions are disposed at discrete positions along the rod. Threaded sections are longitudinally separated by threads without threads. Threaded portions comprise a series of turns extending at least partially around the circumference around the rod. Each of the plurality of threaded portions has at least two cutting grooves formed by a recess formed radially in the screw shaft and extending longitudinally along the length of the threaded portions such that the turns of the threaded portions are formed into at least two discontinuous thread segments extending along the circle around the rod. Plurality of non-threaded portions are narrowed longitudinally along the shaft in the proximal-distal direction. Plurality of threaded portions proximally adjacent to a plurality of tapered, threadless portions comprise at least one thread turn narrowed at the same angle as the narrowing of the adjacent non-threaded portion. Set of adjustable-length bone screws for use in a surgical operation, in which the screws are inserted into the bone, comprises a plurality of the above-mentioned bone screws with an adjustable length. Each of the adjustable-length bone screws has an initial length formed by the distance between the proximal end of the head and the distal tip. Method for setting the size of the above-mentioned bone screw with adjustable length comprises the following steps: determining a desired length of the bone screw with a variable length, the adjustable length bone screw having an initial length that is longer than the desired length, and cutting off the initial length of the adjustable bone length screw to form a length-cut bone screw having the desired length. Method of manufacturing the above-mentioned bone screw with adjustable length comprises the steps: (a) producing a bone screw having a screw head, a stem and a distal tip; (b) forming a plurality of threaded portions having a proximal and distal end along the rod; (c) forming a first and a second recess cut into a rod along the length of each of a plurality of threaded portions at respective distal ends to form two cutting grooves in the threaded portions, so that each of the plurality of threaded portions has two discontinuous circumferential thread segments along a respective length; (d) forming a plurality of non-threaded portions along the rod, the plurality of threaded portions being bounded by the threadless portions and at the proximal and distal ends, (e) forming a narrowed region with a first angle longitudinally along the shaft in the proximal-distal direction in a plurality of sections from a plurality of non-threaded portions and forming a second-angle constriction in a plurality of portions of the plurality of threaded portions, wherein the first angle is the same as the second angle. 
     EFFECT: inventions make it possible to easily cut the bone screw prior to the surgical procedure or during it to adjust the length of the screw to the desired length. 
     10 cl, 7 dwg