Anterior Cervical Fusion
What is anterior cervical fusion?
An anterior cervical fusion is performed through an incision in the front of the neck. The procedure is used to remove pressure from nerve roots or the spinal cord caused by bone spurs or a herniated disc, or to stop the motion between two or more vertebrae. Removing pressure from the nerve roots or spinal cord can ease arm pain. Problems from pressure on the nerves, such as numbness or weakness in the arm or difficulty walking, may also improve. Fusion of the problem vertebrae reduces mechanical pain caused from too much motion in the spinal segment.
How anterior cervical fusion works
Anterior cervical discectomy is one of the most common surgical procedures for problems in the cervical spine. The term discectomy means to "remove the disc." This procedure is routinely used to relieve pressure on a spinal nerve or the spinal cord caused by a herniated disc.
Discectomy is also done when the surgeon intends to fuse two or more bones of the neck together. This procedure of disc removal and fusion is often used to treat degenerative problems (called spondylosis) in the neck.
In the cervical spine, the disc is usually removed from the front. An incision is made in the front of the neck beside the trachea (windpipe). The muscles are moved to the side. The arteries and nerves in the neck are also protected.
Upon reaching the front of the spine, the surgeon uses an X-ray to identify the correct disc. The problem disc is removed all the way back to the spinal cord. If any bone spurs are found sticking off the back of the vertebrae and your surgeon thinks they may also be causing you pain, they may be removed at the time of surgery. Great care is taken to not damage the spinal cord and nerve roots.
Anterior cervical fusion
After the disc has been removed between the vertebrae, a cervical fusion is performed. The space where the disc was taken out is filled with a block of bone taken from the top rim of the pelvis. Bone taken from your own body is called autograft. Your surgeon may obtain bone from a source other than your body, called allograft. Placing a bone graft between two or more vertebrae causes the vertebrae to fuse.
The anterior cervical fusion may also be done in a way that spreads the vertebrae apart a bit, trying to restore the space between them. This is done to recreate the normal height of the disc space and to restore the normal inward curve of the neck (called lordosis). Increasing the distance between the vertebrae also widens the opening (foramina) where the nerves come out of the spine. Restoring the size of the foramina is done to relieve pressure and irritation from bone spurs where the nerves pass through the foramina.
Most neck problems are from a degenerative, or aging, condition of the spine. Degenerative disc disease and cervical stenosis are two diagnoses that can lead to pressure on the spinal cord or nerve roots. Surgery to remove this pressure can be done from the front (anterior) or back (posterior) of the neck. Doctors use the anterior approach more often because the pressure is usually on the front portion of the nerves or spinal cord.
Anterior interbody fusion
When an interbody fusion is done, the disc between two vertebrae is removed, and a bone graft is positioned in its place. As the body heals, the graft fuses to the vertebrae above and below it. When more than one disc needs to be removed, a larger bone graft is inserted. Patients usually wear a brace after the surgery. The brace limits movement between the vertebrae, increasing the chances for a successful fusion.
Bone heals best when it is held still-without motion between the pieces trying to heal. The healing of a fusion is no different than healing a fractured bone, such as a broken arm. However, the neck is one part of the body that is difficult to hold still, even with a brace worn around the outside of the neck. Wearing a brace for several months after the surgery can be uncomfortable.
The success of a fusion can also be improved by screwing metal (titanium) plates or rods to the front of the spine. This holds the vertebrae and graft rigidly in place while the fusion heals. These implants are referred to as instrumentation or internal fixation. There are many different types of spinal implants used with the intent of stabilizing the neck and maximizing healing of the fusion. When doctors use this type of instrumentation, a brace may be needed for a shorter period of time, or not at all.