Implants for spinal fixation and or fusion

A method, comprising:

• assembling a composite bone implant prior to implantation within a patient, the composite bone implant including a monolithic elongate shank and a sleeve that are both sized, configured and arranged to be coupled together to form the composite implant and remain implanted in the patient following implantation, wherein the assembling step comprises,
• rotationally moving one or both of the monolithic elongate shank and the sleeve relative to the other to position the monolithic elongate shank within the sleeve such that a sleeve inner thread and a shank outer thread interface and thereby resist axial motion between the shank and the sleeve at the location of the interface and such that the sleeve is disposed over at least a central portion of the shank, wherein rotationally moving one or both of the monolithic elongate shank and the sleeve relative to the other positions a shank distal thread distal to a distal end of the sleeve,
• wherein, once assembled, the composite implant has a central region that includes a growth region of the sleeve, the growth region of the sleeve comprising at least one thread, a plurality of lattice structures, and a plurality of fenestrations through the sleeve, wherein the plurality of lattice structures and the plurality of fenestrations are disposed axially between the at least one thread in the growth region of the sleeve.

A method, comprising:

• assembling a composite bone implant prior to implantation within a patient, the composite bone implant including a monolithic elongate shank and a sleeve that are both sized, configured and arranged to be coupled together to form the composite implant and remain implanted in the patient following implantation, wherein the assembling step comprises,
• rotationally moving one or both of the monolithic elongate shank and the sleeve relative to the other to position the monolithic elongate shank within the sleeve such that a sleeve inner thread and a shank outer thread interface and such that the sleeve is disposed over at least a central portion of the shank, wherein rotationally moving one or both of the monolithic elongate shank and the sleeve relative to the other positions a shank distal thread distal to a distal end of the sleeve,
• wherein, once assembled, the composite implant has a growth region of the sleeve in a central region of the composite implant, the growth region of the sleeve comprising at least one thread, a plurality of lattice structures, and a plurality of fenestrations through the sleeve, wherein the plurality of fenestrations are axially between the at least one thread in the growth region of the sleeve.