Bone screw incorporating a porous surface formed by an additive manufacturing process
Inventors
Assignees
Renovis Surgical Technologies Inc • Kyocera Medical Technologies Inc
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Publication Number
US-10561456-B2
Publication Date
2020-02-18
Expiration Date
Abstract
The present invention provides a bone screw or bone anchor, such as a threaded pedicle screw or the like, incorporating a porous surface for enhancing bony fixation, ingrowth, and purchase when implanted in bone. Preferably, this porous surface covers at least a portion of the threads of the bone screw or bone anchor. The porous surface is formed by a conventional or novel additive manufacturing process, such as three-dimensional (3D) printing or the like, optionally as well as a prior and/or subsequent machining process. The porous surface may include novel needle-like protrusions and/or lattice structures, and/or any other protruding/depressed features, whether regular or irregular.
Core Innovation
The invention is directed to a bone screw having a threaded shaft portion, a head portion coupled to the threaded shaft portion, and a tip portion coupled to the threaded shaft portion opposite the head portion. One or more threads are disposed concentrically about the threaded shaft portion, and at least some threads comprise a base and a porous surface coupled to the base, where the porous surface comprises lattice structures including intersecting struts.
The porous surface is formed to approximate a scanned three-dimensional spongy bone surface and comprises a plurality of needles. Some of the plurality of needles are relatively longer needles anchored both directly to the base and directly to the intersecting struts, while some intervening needles are relatively shorter and are anchored directly only to the intersecting struts and not directly to the base, being spaced apart from the base.
The plurality of needles comprise at least two different shapes and are disposed in at least two different orientations with respect to the base. The external portions of the porous surface and the plurality of needles are microtextured, and scanned three-dimensional spongy bone surface information is used to generate fabrication data for the additively manufactured porous surface.
Claims Coverage
The document provides one independent claim with multiple dependent claims. The independent claim defines 4 inventive features centered on a bone screw with a porous, lattice-structured surface approximating a scanned 3D spongy bone surface, a structured population of needles with distinct anchoring behaviors, shapes, and orientations, and microtextured external portions.
Bone screw with porous lattice-structured threaded surface
A bone screw comprising a threaded shaft portion, a head portion coupled to the threaded shaft portion, and a tip portion coupled to the threaded shaft portion opposite the head portion, with one or more threads disposed concentrically about the threaded shaft portion and at least some threads comprising a base and a porous surface coupled to the base, the porous surface comprising lattice structures including intersecting struts.
Porous surface approximating scanned spongy bone with long and short anchored needles
The porous surface is formed to approximate a scanned three-dimensional spongy bone surface and comprises a plurality of needles, including relatively longer needles anchored both directly to the base and directly to the intersecting struts, and relatively shorter intervening needles anchored directly only to the intersecting struts and not directly to the base, being spaced apart from the base.
Needle population with at least two shapes and at least two orientations
The plurality of needles comprise at least two different shapes and are disposed in at least two different orientations with respect to the base.
Microtextured external portions of porous surface and needles
External portions of the porous surface and the plurality of needles are microtextured.
Overall, the claim coverage centers on a bone screw whose threaded porous surface includes intersecting struts forming lattice structures, with long and short needles having different anchoring locations relative to the base, at least two needle shapes and at least two orientations, and microtextured external portions.
Stated Advantages
enhance bony fixation/ingrowth/purchase
improved bony anchorage via osteoblast adherence
Documented Applications
A workflow using micro-CT scanned spongy bone to generate texture data and additive fabrication files for forming an osteo-porous porous surface approximating the scanned three-dimensional spongy bone surface.
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