Anterior Cervical Fusion


The cervical spine (neck) contains not only spinal nerves to the arms, but also the spinal cord carrying signals to and from the lower body, bowel, bladder, and legs. A herniated disc or stenosis in the neck can be serious, especially if spinal cord damage is evident on physical exam or as seen on MRI scan.

If a midline disc protrusion is compressing the spinal cord, it is impossible to remove it from the back, for even after removing the lamina, the spinal cord in between the surgeon and the disc and the spinal cord cannot be retracted without damaging it.

Consequently the disc has to be removed through the front of the neck. The exposure is easy by going between the strap muscle on one side and the trachea and esophagus toward the midline. That requires only a 2-3 inch incision from the midline to the strap muscle, done horizontally in a normal skin fold for cosmetic reasons.

However, to reach the herniating portions of disc, one must go through the entire disc from front to back, then remove any ridges of bone on the edges of the adjacent vertebrae to relieve the spinal cord compression. After that, there is not disc left. Therefore, something must be put in to replace the disc.

If only one disc is bad and all the others good, an artificial disc can be put in to replace the disc and keep some motion in that segment of the spine. However, many patients will have more than one degenerated disc and won’t qualify for disc replacement. Therefore a graft is put in between the two vertebrae that will grow together with them, “fusing” the two vertebra in place.

Graft material can be cadaver bone grafts, the patient’s own bone, or hollow hard carbon fiber hollow plugs that can be filled with graft bone. The best chance for fusion is with the patient’s own bone, but the donor site in the hip can be painful. When I do a two level fusion (taking out two discs and fusing three vertebrae), I always recommend using the patient’s own bone to get the best results. One level fusions work well with the hollow implant filled with chips of bone from the patient’s vertebrae taken during the operation, plus materials called graft extenders.

The down side of a fusion is throwing more stress on the discs above and below the fused level causing them to wear out faster. That is called adjacent segment degeneration and can result in the need for more fusions later. That is the reason for using the artificial disc whenever possible.

A simple operation from the back, without the need for a fusion, called posterior microdiscectomy is described in the section on Cervical (Neck) Disc Herniation on the Home Page.