Abstract: A polyaxial orthopedic device for use with rod implant apparatus includes a screw having a bowl-shaped head and a coupling element. The coupling element has a rod receiving channel and an axial bore into which the head of the screw may be inserted. The interior surface of the bore is inwardly curvate at the lower end thereof to form a socket for polyaxially retaining the curvate head of the screw. In an initial position the screw head remains polyaxially free with respect to the coupling element. There is also a hemispherical insert which is seated on the top of the screw head, permitting it to rotate, but which may be compressed onto the head to permit the head of the screw to be locked in the bore. The rod is inserted into the channel and a top locking nut or set screw locks presses down on the rod and hemispherical insert to secure the assembly completely.

Abstract: A modular polyaxial pedicle screw and orthopaedic rod implant device including same includes a shaft portion, a cuff, a stem portion, and a rod coupling sub-assembly. The shaft portion is designed to be inserted into the pedicle, has a hemispherical upper portion, and includes a second threading formed on the exterior surface adjacent to the hemispherical protuberance. The stem portion is a threaded post having an enlarged lower socket portion which includes a spherical recess formed at the base thereof, the recess being ideally suited to polyaxially rotate on the hemispherical upper portion of the shaft. The cuff is a cylindrical element designed to seat around the interface of the hemispherical portion of the shaft and the lower socket portion of the stem, initially so that the stem and shaft may polyaxially rotate relative to one another, and subsequently to hold the stem and shaft in final securement.

Abstract: The present invention is a selectively expandable bone fixation screw-sleeve device which provides substantially greater holding strength in human bone than other bone screw devices. The sleeve element of this invention includes several embodiments, each having at least one corresponding screw element for selectively expanding a portion of the sleeve once it has been inserted into the bone. More specifically, in several embodiments, the sleeve includes a series of vertical slots in the end, or ends, of the cylindrical body of the sleeve. The slots define, therebetween, sections which are contiguous with the remainder of the cylindrical body, and which may rotate radially outward. In these embodiments, the sections are designed having a varying thickness, for example a single or double wedge profile, such that the insertion of the screw element into the sleeve deforms the shape of the sleeve by causing the sections to flair outward.

Abstract: A compression locking variable length cross-link device having modular components, including rod and/or pedicle screw coupling elements each having a hole which may be disposed co-linearly with respect to other such holes in opposing elements such that a threaded hinge-post may be inserted therein. A nut is utilized to compress the elements together to rigidly secure the elements once they have been properly positioned relative to one another. In an additional set of embodiments, a linkage member having an elongate hole therein may be used to couple similar elements thereto in a similar flexible hinge-post manner such that the elements may be coupled to the linkage member instead of to the opposing elements directly.

Abstract: A bidirectional rod locking mechanism for use with rod coupling elements of orthopaedic rod apparatus includes a rod coupling element having a hook-shaped rod receiving end and a threaded axial bore. The axial bore is disposed so close to the hook-shaped portion that the medial portion of the hole protrudes through the inner surface of the hook portion. A contoured threaded shaft is advanced into the bore such that the contoured medial portion thereof aligns with the inner surface of the hook to permit the receipt therein of a rod. The threadable translation of the shaft in the appropriate direction causes a misalignment of the contoured medial portion in a manner which prevents the rod from being removed from the hook-shaped receiving locus.