Patent ID: 8852252
Filing Date: 2014-10-07
Classification: A61B

Abstract:
1. An endosseous screw for fixing a plate to a bone site, comprising: a shaft at least partially threaded, means to insert the screw into a bone site, and a distal portion provided for engaging the plate to fasten it to the bone site, said distal portion comprising a head and a conical threaded portion, the conical threaded portion being adjacent to the shaft and suitable for threadedly engaging a hole of the plate, wherein the head comprises curvilinear facets defining an external peripheral profile having a convex barrel-like shape, wherein the facets are even in number and define a regular polygonal section along a median section of the head, said median section being a section positioned on a plane perpendicular to the longitudinal axis of the screw and dividing each facet into two identical curvilinear portions which mirror each other with respect to the median section, said portions of each facet defining the external peripheral profile of the head of the screw, and wherein the distal portion is configured in such a manner that when the conical threaded portion engages the hole of the plate, the head in its entirety projects externally from the plate, so that the facets remain exposed in order to allow a stable coupling with a tubular manipulating wrench, the stable coupling being maintained during an untightening phase of the screw from the plate, even when the tubular manipulating wrench is oriented in an inclined direction with respect to a longitudinal axis of the endosseous screw.