High X-Ray Lucency Lattice Structures

Abstract

The biocompatible lattice structures and implants disclosed herein have an increased or optimized lucency, even when constructed from a metallic material. The lattice structures can also provide an increased or optimized lucency in a material that is not generally considered to be radiolucent. Lucency can include disparity, maximum variation in lucency properties across a structure, or dispersion, minimum variation in lucency properties across a structure. The implants and lattice structures disclosed herein may be optimized for disparity or dispersion in any desired direction. A desired direction with respect to lucency can include the anticipated x-ray viewing direction of an implant in the expected implantation orientation.

1 . A medical implant, comprising:
 a porous structure disposed within an implant volume, the porous structure comprising:   a plurality of repeating unit cells, each defined by a plurality of nodes and plurality of struts extending from at least one node;   wherein the plurality of struts are fixed and configured such that overlap of struts in a predetermined viewing direction, within the implant volume, is minimized.   
     
     
         2 . The medical implant of  claim 1 , wherein the predetermined viewing direction comprises a direction relative to the implant volume. 
     
     
         3 . The medical implant of  claim 1 , wherein the porous structure further comprises a lattice structure. 
     
     
         4 . The medical implant of  claim 1 , wherein the plurality of repeating unit cells are configured to form a lattice structure comprising at least one of: radial dodeca-rhombus, rhombic dodecahedron, modified rhombic dodecahedron, diamond, dodecahedron, square, pentagonal, hexagonal, octagonal, sctet struts, trunic octa, diagonal struts, and reinforced versions of each of said geometries. 
     
     
         5 . The medical implant of  claim 1 , wherein the predetermined viewing direction further comprises a direction of anticipated x-ray viewing after implantation of the medical implant. 
     
     
         6 . The medical implant of  claim 1 , wherein the plurality of repeating unit cells are elongated in a direction normal to at least one of: an anticipated direction of new bone growth and an expected direction of physiological loading. 
     
     
         7 . The medical implant of  claim 1 , wherein the medical implant further comprises:
 a body comprising a metallic lattice structure;   a first endplate comprising an upper surface for contacting a first segment of bone and a lower surface fixed to the body;   a second endplate comprising a lower surface for contacting a second segment of bone and an upper surface fixed to the body, the second endplate being spaced apart and mechanically connected to the first endplate via the body, the body being at least partially disposed between the first and the second endplates;   wherein an elastic modulus of each of the first endplate and second endplate is higher than an elastic modulus of the body and at least one of the first and second endplates comprises a metal.   
     
     
         8 . The medical implant of  claim 1 , wherein the plurality of struts further comprise internal voids. 
     
     
         9 . The medical implant of  claim 1 , wherein the plurality of struts further comprise a structure comprising at least one of a U-channel, an I-beam and an H-beam. 
     
     
         10 . The medical implant of  claim 1 , wherein the plurality of nodes further comprise internal voids. 
     
     
         11 . The medical implant of  claim 1 , comprising :
 a first metallic volume and a second metallic volume, the first and second volume being coupled to the porous structure; and   a predetermined x-ray viewing direction;   wherein the first volume is positioned within the porous structure to at least partially overlay the second volume when the medical implant is viewed in the predetermined x-ray viewing direction.   
     
     
         12 . The medical implant of  claim 11 , wherein the first volume comprises at least one of an enlarged strut, an enlarged node and a filled unit cell. 
     
     
         13 . The medical implant of  claim 11 , wherein the first volume comprises a volumetric density of about 100 percent. 
     
     
         14 . The medical implant of  claim 11 , wherein the first volume comprises a volumetric density of less than 100 percent. 
     
     
         15 . The medical implant of  claim 11 , wherein the first volume comprises a volumetric density between and including 0 percent to 30 percent. 
     
     
         16 . The medical implant of  claim 1 , comprising: a first void coupled to the porous structure, the first void providing a localized difference in lucency configured to deviate from an average baseline lucency by at least 4 percent when in an aligned direction, the average baseline lucency comprising an average lucency across the porous structure. 
     
     
         17 . The medical implant of  claim 1 , wherein the predetermined viewing direction further comprises a direction of anticipated viewing during implantation of the medical implant. 
     
     
         18 . The medical implant of  claim 17 , wherein the implantation comprises an image guided surgery. 
     
     
         19 . The medical implant of  claim 17 , wherein the implantation comprises a robotic surgery. 
     
     
         20 . A medical implant, comprising:
 a porous structure disposed within an implant volume, the porous structure comprising:   a plurality of repeating unit cells, each defined by a plurality of nodes and plurality of struts extending from at least one node;   wherein the plurality of struts are fixed and configured such that overlap of struts in a predetermined viewing direction, within the implant volume, is maximized.