Anterior cervical discectomy and fusion is a surgical procedure to treat nerve root and/or spinal cord compression by decompressing (freeing up) the spinal cord and nerve roots of the cervical spine (neck) followed by a fusion in order to stabilize the vertebrae. This procedure is used when other conservative, non-surgical treatments have failed (such as physical therapy and/or injections to name a few). As is the case with a lumbar fusion, the ACDF procedure itself does not immediately result in a fusion. The procedure fixates an area that is causing pain using a low profile plate and screws and inthis enviroment the body grows bone. Thus a fusion is created by the body, the surgery simply set the stage for this to occur.
This procedure is normally performed from the front of the neck for several reasons; the most important being that manipulation of the spinal cord is minimized with this approach. Secondarily, the front of the neck has a thin layer of musculature (the platysma) that once passed through, allows for excellent access to the cervical discs and vertebrae with minimal tissue injury. Once to the vertebrae and disc, all disc material at each affected level is removed along with any bone spurs that may also be present. Bone spurs that may be present are a result of arthritis and are the body’s first step in trying to stop motion where arthritis is present. Bone spurs are problematic in areas where they compress against the spinal cord and/or exiting nerves and should be removed. After the disc material and pertinent bone spurs are removed, a replacement disc spacer is placed within the now empty disc space. This spacer is usually made of either cadaver bone or a hard plastic spacer.
Bone grafts come from many sources. Each type has advantages and disadvantages.
- Autograft bone comes from you. The surgeon takes your own bone cells from the hip (iliac crest). This graft has a higher rate of fusion because it has bone-growing cells and proteins. The disadvantage is the pain in your hipbone after surgery. Harvesting a bone graft from your hip is done at the same time as the spine surgery. The harvested bone is about a half inch thick – the entire thickness of bone is not removed, just the top half layer.
- Allograft bone comes from a donor (cadaver). Bone-bank bone is collected from people who have agreed to donate their organs after they die. This graft does not have bone-growing cells or proteins, yet it is readily available and eliminates the need to harvest bone from your hip. Allograft is shaped like a doughnut and the center is packed with shavings of living bone tissue taken from your spine during surgery.
- Bone graft substitute comes from man-made plastic, ceramic, or bioresorbable compounds. Often called cages, this graft material is packed with shavings of living bone tissue taken from your spine during surgery.
- Bone Marrow Aspirate is obtained by pulling blood from the iliac crest (hip) which is rich in precursor cells that when placed in a bony environment will develop into bone forming cells. This blood is placed on the graft material that is to be placed within the disc space. The goal is to increase the chances that bone will grow in this area creating a successful fusion.
The next step in the procedure is to fixate a plate with screws across the vertebrae above and below where the disc was removed and replaced by a disc spacer. This hardware has a low profile and will stay within the body indefinitely. The procedure is finished by suturing together the platysma muscle and overlying skin. In some cases, a temporary drain will be placed beneath the platysma prior to its closure to allow for fluid that normally accumulates in the surgical area to drain off slowly.
After fusion you may notice some range of motion loss, but this varies according to neck mobility before surgery and the number of levels fused. If only one level is fused, you may have similar or even better range of motion than before surgery. If more than two levels are fused, you may notice limits in turning your head and looking up and down. Motion-preserving artificial disc replacements have emerged as an alternative to fusion. Similar to knee replacement, the artificial disc is inserted into the damaged joint space and preserves motion, whereas fusion eliminates motion. Outcomes for artificial disc compared to ACDF are similar, but long-term results of motion preservation and adjacent level disease are not yet proven. Talk with your surgeon about whether ACDF or artificial disc replacement is most appropriate for you.
Who is a candidate?
You may be a candidate for discectomy if you have:
- diagnostic tests show that you have a herniated or degenerative disc
- significant weakness in your hand or arm
- arm pain worse than neck pain
- symptoms that have not improved with physical therapy or medication