The invention relates to the development of a discontinuous coating using a bioabsorbable and bioactive biomaterial (which can be a bioceramic, a biopolymer or a bioactive composite) applied to solid (smooth, rough or porous) substrates. This discontinuous coating should be totally consumed in up to 10 days after implantation, so that in the end only the interface of the newly formed tissue with the implant remains. The proposed discontinuous coating can be obtained by any method that allows depositing a continuous layer, once the process parameters are duly adjusted. The preferred method for applying this discontinuous layer is airbrushing or air atomizing. The preferred biomaterial is bioglass.

Superior and/or inferior facets of one or more facet joints may be replaced by superior and/or inferior facet joint prostheses. In one embodiment, a kit of superior or inferior prostheses is provided, in which the prostheses have at least two dimensions that vary among members of the kit independently of each other. Each prosthesis may have a bone engaging surface having a surface that is polyaxially rotatable against a corresponding resection of a vertebra. Each prosthesis may also have an articulating surface shaped such that, after attachment to the spine, the replaced or partially replaced facet joints provide a larger medial-lateral range of motion when the spine is flexed than when the spine is extended. Crosslinks may be used to connect left and right prosthesis together in such a manner that they are stabilized in a position in which they are seated directly against the vertebra.

Methods for altering the natural history of degenerative disc disease and osteoarthritis of the spine are proposed. The methods focus on the prevention, or delayed onset or progression of, subchondral defects such as bone marrow edema or bone marrow lesion, and subchondral treatment to prevent the progression of osteoarthritis or degenerative disc disease in the spine and thereby treat pain.

Superior and/or inferior facets of one or more facet joints may be replaced by superior and/or inferior facet joint prostheses. In one embodiment, a kit of superior or inferior prostheses is provided, in which the prostheses have at least two dimensions that vary among members of the kit independently of each other. Each prosthesis may have a bone engaging surface having a surface that is polyaxially rotatable against a corresponding resection of a vertebra. Each prosthesis may also have an articulating surface shaped such that, after attachment to the spine, the replaced or partially replaced facet joints provide a larger medial-lateral range of motion when the spine is flexed than when the spine is extended. Crosslinks may be used to connect left and right prosthesis together in such a manner that they are stabilized in a position in which they are seated directly against the vertebra.