Introduction

Anterior cervical discectomy and fusion (ACDF) is a procedure used to treat neck problems such as disc herniations, fractures, and spinal instability. In this procedure, the doctor enters the neck from the front (the anterior region) and removes a spinal disc (discectomy). The vertebrae above and below the disc are then held in place with bone graft and sometimes also metal hardware. The goal is to help the bones to grow together into one solid bone. This is known as fusion. The medical term for fusion is arthrodesis.

Rationale

In most cases, ACDF is used to stop symptoms from cervical disc disease. Discs start to degenerate as a natural part of aging and also from stress and strain in the structures of the neck. Over time, the disc begins to collapse, and the space decreases between the vertebrae.

When this happens, the opening around the spinal nerves (the neural foramina) narrows and may begin to put pressure on the nerves. The long ligaments in the spine slacken. They may even buckle and put pressure on the spinal cord. The outer rings of the disc (annulus) weaken and develop small cracks. The nucleus in the center of the disc may press on the weakened annulus and actually squeeze out of the annulus. The herniated disc may press on ligaments, nerves, or even the spinal cord. Fragments of the disc that press against the outer annulus, spinal nerves, or spinal cord can be a source of pain, numbness, and weakness. Pressure on the spinal cord, called myelopathy, can also produce problems with the bowels and bladder, changes in the way you walk, and trouble with fine motor skills in the hands.

Discectomy is the removal of the disc (and any fragments) between the vertebrae that are to be fused. When symptoms are coming from the disc, it is hoped that this step stops the symptoms.

Once the disc is removed, doctors spread the bones of the spine apart slightly to make room for the bone graft. The bone graft separates and holds the vertebrae apart. Enlarging the space between the vertebra widens the opening of the neural foramina, taking pressure off the spinal nerves that pass through them. Also, the ligaments inside the spinal canal are pulled taut so they don't buckle into the spinal canal.

No movement occurs between the bones that are fused together. By holding the sore part of the neck steady, the fusion helps relieve pain. And it prevents additional wear and tear on the structures inside the section that was fused. Not only does this keep bone spurs from forming, but it has been shown that fusion causes existing bone spurs to shrink. By fusing the bones together, doctors hope that patients won't have future pain and problems from cervical disc disease. 

Surgical Procedure

Patients are given a general anesthesia to put them to sleep during most spine surgeries. As you sleep, your breathing may be assisted with a ventilator.

The patient's neck is positioned facing the ceiling with the head bent back and slightly to the right. A two-inch incision is made two to three fingers width above the collar bone across the left-hand side of the neck. Doctors often choose the left side to avoid injuring the nerve going to the voice box. Retractors are used to gently separate and hold the neck muscles and soft tissues apart so the doctor can work on the front of the spine.

A needle is inserted into the disc, and an X-ray is taken to identify the correct disc. A long strip of muscle and part of the long ligament that covers the front of the vertebral bodies are carefully pulled to the side. Forceps are used to take out the front half of the disc. Next, a tool is attached to the vertebrae to spread them apart. This makes it easier for the doctor to see between the two vertebrae. A small rotary cutting tool (a burr) is used to carefully remove the back half of the disc. A special microscope is used to help the doctor see and remove pieces of disc material and bone spurs near the spinal cord.

A layer of bone is shaved off the flat surfaces of the two vertebrae. This causes the surfaces to bleed. This is necessary to help the bone graft heal and join the bones together.

The doctor measures the depth and height between the two vertebrae. A section of bone is grafted from the top part of the pelvis. It is measured to fit snugly in the space where the disc was taken out. The doctor separates the two vertebrae, and the graft is tamped into place.

The doctor tests the graft by bending and turning the neck to make sure it is in the right spot and is locked in place. Another X-ray may be taken to double check the location of the graft.

Some surgeons use metal hardware to "lock" the bones in place. This hardware includes metal plates and screws that are fastened to the neck bones. They hold the neck bones still so the graft can heal, replacing the need for a rigid neck brace.

A drainage tube may be placed in the wound. The muscles and soft tissues are put back in place, and the skin is stitched together. The doctor may place your neck in a rigid collar.

As with all major surgical procedures, complications can occur. Some of the most common complications following this ACDF include problems with anesthesia, thrombophlebitis, infection, nerve damage, problems with the graft, nonunion, and ongoing pain

After Surgery

After ACDF, patients usually wear a special neck brace for several months. These neck braces are often bulky and restrictive. However, the bone graft needs time to heal in order for the fusion to succeed. This requires the neck to be held still.

Patients may stay in the hospital after surgery for one to two days. When the surgery is done on an outpatient basis, patients may even go home the same day of surgery. Patients can get out of bed as soon as they feel up to it. They are watched carefully when they begin eating to make sure they don't have problems swallowing. They usually drink liquids at first, and if they are not having problems, they can start eating solid food.

Patients are able to return home when their medical condition is stable. However, they are usually required to keep their activities to a minimum in order to give the graft time to heal.

Rehabilitation

Rehabilitation after ACDF can be a slow process. You will probably need to attend therapy sessions for two to three months, and you should expect full recovery to take up to eight months.

Many doctors prescribe outpatient physical therapy beginning a minimum of four weeks after surgery. At first, treatments are used to help control pain and inflammation. Ice and electrical stimulation treatments are commonly used to help with these goals. Your therapist may also use massage and other hands-on treatments to ease muscle spasm and pain.

Active treatments are slowly added. These include exercises for improving heart and lung function. Walking and stationary cycling are ideal cardiovascular exercises. Therapists also teach specific exercises to help tone and control the muscles that stabilize the neck and upper back.