When a dorsal fusion is done in combination with a TLIF or PLIF, it is called a 360 fusion. 360 fusions offer more stability than a simple fusion alone and hence a greater chance of a successful bone fusion. The major difference between the TLIF and PLIF is that the TLIF entry is about 1 cm more medial. In the TLIF and PLIF a cage is put in from both sides (left and right of the spine) into the intervertabral disc space. Some new cages, which are banana shaped, have been developed to have an entry from only one side. The TLIF and PLIF bear the load of the intervertebral disc space. The dorsal fusion of facet joints does not create a structure, which can bear the entire weight of the body, particularly over many years. Without intervertebral support 80 percent of the body's weight is shifted to the dorsal area of the spine.

Dorsal fusions are also done with anterior fusions (ALIF), when it is appropriate. An anterior fusion is even stronger, because the cages can be larger and therefore give more opportunity for bones to grow together.

Dorsal fusions are also a practical way to deal with ADRs, which are partially subsided.

A dorsal fusion is made by creating a bony bridge in the facet joint. The cartilage and synovial sac of the facet joint are removed and the bone on the inside surfaces of the facet joint is roughed up to encourage osteophyte growth. A small piece of bone or other material in place inside the facet joint after the pedicle screws are implanted. The connecting rods to the screws are used to compress the facets and their contents together until bone ingrowth is completed.

Once the fusion is complete, the screws and rods can be removed, but they are never removed unless there is another operation in the area and there is a need for removal. And the screws are never removed, if it is a dorsal fusion only, because the bones of the posterior spine alone could not support the weight of the body without something supporting the interverebral disc space. The DSS system offers pedicle screws and connectors, which allow for connections between the fused segments and the motion segment. This is quite unique in the spine world and is preferred by Dr. Bertagnoli. Therefore, if you need something else at an adjacent level in the future and you had the dorsal fusion now, the screws and connectors of the DSS could allow for inter-connectivity between the motion and fused sections, yielding greater stability.