Semi-Constrained Bone Screw And Insertion Instrument
AssigneeK2M, Inc.
InventorsTodd Wallenstein, Megan Carnes, John Donohoe
Life of this patent
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Abstract
A bone screw for attaching a spinal prosthetic or bone plate to bone includes a tubular body having open proximal and distal ends. The open proximal and distal ends define a passageway therethrough. A shaft is insertable into the passageway and includes a distal tip that extends beyond the open distal end. The shaft is insertable through a lumen of a head of the bone screw. A gap is defined between a distal surface of the head and a proximal end of the tubular body. The shaft is rotationally fixed with the tubular body and the head. The head is repositionable with respect to the shaft such that an acute angle is defined between the head and a longitudinal axis of the shaft.
Claims20
A bone screw comprising:
- a tubular body defining a first longitudinal axis and having open proximal and distal ends defining a passageway therethrough;
- a helical thread circumscribing an outer surface of the tubular body;
- a head having a lumen extending therethrough, wherein a portion of an interior surface of the lumen tapers inwardly toward a distal opening of the lumen;
- and
- a shaft insertable through the lumen of the head and the passageway of the tubular body and into engagement therewith to rotatably fix the shaft relative to the tubular body, wherein a proximal portion of the shaft is flared outwardly and has a maximum diameter greater than a diameter of the distal opening of the lumen of the head, the shaft defining a second longitudinal axis, wherein the shaft couples the head to the tubular body such that a gap is defined between a distal surface of the head and the open proximal end of the tubular body, the head repositionable with respect to the first longitudinal axis of the tubular body and the second longitudinal axis of the shaft,
- wherein a portion of the interior surface of the lumen of the head at the distal opening tapers outwardly to increase an angular range of the head relative to the shaft.
Dependencies are inferred from the claim text.