Threaded composite interbody device and associated manufacturing method

Abstract

A composite threaded interbody device includes (a) an outer surface that is cylindrical or conical, (b) a plastic core having two outer sections, each of the outer sections forming a respective portion of the outer surface and spanning a respective azimuthal range in an azimuthal dimension relative to a longitudinal axis of the outer surface, the outer sections being separated from each other in the azimuthal dimension by two recessed sections that are recessed from the outer surface, and (c) two threaded endplates coupled to the two recessed sections and spanning gaps between the outer sections, to complete the outer surface.

What is claimed is: 
     
         1 . A composite threaded interbody device, comprising:
 an outer surface that is cylindrical or conical;   a plastic core having two outer sections, each of the outer sections forming a respective portion of the outer surface and spanning a respective azimuthal range in an azimuthal dimension relative to a longitudinal axis of the outer surface, the outer sections being separated from each other in the azimuthal dimension by two recessed sections that are recessed from the outer surface; and   two threaded endplates coupled to the two recessed sections and spanning gaps between the outer sections, to complete the outer surface.   
     
     
         2 . The composite threaded interbody device of  claim 1 , each of the outer sections being threaded. 
     
     
         3 . The composite threaded interbody device of  claim 2 , threads of the outer sections cooperating with threads of the threaded endplates to form a common thread of the outer surface, the common thread spiraling about the longitudinal axis. 
     
     
         4 . The composite threaded interbody device of  claim 3 , the common thread being interrupted by one or more channels passing through the composite threaded interbody device. 
     
     
         5 . The composite threaded interbody device of  claim 1 , diameter of the outer surface being uniform along the longitudinal axis such that the threaded outer surface is cylindrical. 
     
     
         6 . The composite threaded interbody device of  claim 1 , diameter of the outer surface decreasing along the longitudinal axis from a first end of the composite interbody device to a second end of the composite interbody device, such that the threaded outer surface is conical. 
     
     
         7 . The composite threaded interbody device of  claim 1 , the plastic core forming at least one channel allowing bone growth therethrough. 
     
     
         8 . The composite threaded interbody device of  claim 7 , the at least one channel further including a plurality of lateral channels, each of the lateral channels passing through each of the outer sections. 
     
     
         9 . The composite threaded interbody device of  claim 8 , the at least one channel further including a slot passing through each of the threaded endplates, the slot intersecting the lateral channels. 
     
     
         10 . The composite threaded interbody device of  claim 7 , the plastic core further forming a longitudinal channel spanning length of the plastic core along the longitudinal axis. 
     
     
         11 . The composite threaded interbody device of  claim 1 , each of the endplates being made of metal. 
     
     
         12 . The composite threaded interbody device of  claim 11 , each of the endplates being coated with hydroxyapatite. 
     
     
         13 . The composite threaded interbody device of  claim 1 , length of the outer surface along the longitudinal axis exceeding diameter of the outer surface. 
     
     
         14 . A method for manufacturing a composite threaded interbody device, comprising:
 coupling two endplates in two respective recessed sections of a plastic core such that the endplates cooperate with outer sections of the plastic core, from which the recessed sections are recessed, to form an outer surface of the composite threaded interbody device, the outer surface being cylindrical or conical, the outer sections being separated from each other in an azimuthal dimension, relative to a longitudinal axis of the outer surface, by the recessed sections; and   after the step of coupling, forming, in the endplates and the outer sections, a common thread that spirals about the longitudinal axis.   
     
     
         15 . The method of  claim 14 , further comprising, after the step of coupling, forming at least one channel passing through the composite threaded interbody device between and through the outer sections. 
     
     
         16 . The method of  claim 14 , further comprising coating the endplates with hydroxyapatite. 
     
     
         17 . A method for manufacturing a composite threaded interbody device, comprising:
 coupling two threaded endplates in two respective recessed sections of a plastic core such that the endplates cooperate with outer sections of the plastic core, from which the recessed sections are recessed, to form an outer surface of the composite threaded interbody device, the outer surface being cylindrical or conical, the outer sections being separated from each other in an azimuthal dimension, relative to a longitudinal axis of the outer surface, by the recessed sections.   
     
     
         18 . The method of  claim 17 , further comprising, after the step of coupling, forming at least one channel passing through the composite threaded interbody device between and through the outer sections. 
     
     
         19 . The method of  claim 18 , further comprising coating the endplates with hydroxyapatite. 
     
     
         20 . The method of  claim 17 , further comprising aligning threads of the threaded endplates with threads of the outer sections to form a common thread spiraling about the longitudinal axis.