Performed by – Sri Chatakondu, Sarmad Kazzaz, Mark Thomas, Adam Way

Anterior cervical discectomy and fusion (ACDF) is a surgical procedure performed to remove a herniated or degenerative disc (Fig. 1) in the cervical (neck) spine. The surgeon approaches the spine from the front, through the throat area. After the disc is removed, the vertebrae above and below the disc space are fused together. Your doctor may recommend a discectomy if physiotherapy or medication fails to relieve your neck or arm pain caused by inflamed and compressed spinal nerves. Patients typically go home within a few days; recovery time takes 4 to 6 weeks.

Millions of people suffer from pain in their necks or arms. A common cause of cervical pain is a rupture or herniation of one or more of the cervical discs. This happens when the annulus of the disc tears and the soft nucleus squeezes out. As a result, pressure is placed on the nerve root or the spinal cord and causes pain in the neck, shoulders, arms and sometimes the hands. Cervical disc herniations can occur as a result of ageing, wear and tear, or sudden stress like from an accident.

Most cases of cervical pain do not require surgery and are treated using non-surgical methods such as medications, physical therapy and/or bracing. However, if patients experience significant pain and weakness that does not improve, surgery may be necessary.

Surgical technique
An anterior cervical discectomy (ACD) is the most common surgical procedure to treat damaged cervical discs. Its goal is to relieve pressure on the nerve roots or on the spinal cord by removing the ruptured disc. It is called anterior because the cervical spine is reached through a small incision in the front of the neck (anterior means front). During the surgery, the soft tissues of the neck are separated and the disc is removed. By moving aside the neck muscles, trachea, and oesophagus, the disc and bony vertebrae are accessed. In order to maintain the normal height of the disc space, the surgeon fills the space either with a cage filled with bone graft or a disc replacement. A bone graft is a small piece of bone, either taken from the patient’s body or from a bone bank. This cage fills the disc space and ideally will join or fuse the vertebrae together. This is called fusion.

It usually takes a few months for the vertebrae to completely fuse. In most cases, some instrumentation (such as plates or screws) may also be used to add stability to the spine.

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 (the gold standard) 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 your specific case.

After surgery
Patients will feel some pain after surgery, especially at the incision site. Pain medications are usually given to help control the pain. While tingling sensations or numbness is common, and should lessen over time, they should be reported to the doctor. Most patients are up and moving around within a few hours after surgery. In fact, this is encouraged in order to keep circulation normal and avoid blood clots.

However, most patients need to remain in the hospital, gradually increasing the amount of time they are up and walking, before they are discharged. Prior to discharge the doctor and physiotherapist will provide the patient with careful directions about activities that can be pursued and activities to be avoided. Often patients are encouraged to maintain a daily low-impact exercise program. Walking, and slowly increasing the distance each day, is the best exercise after this type of surgery.

Some discomfort is normal, but pain is a signal to slow down and rest. Keep in mind the amount of time it takes to return to normal activities is different for every patient.

Discomfort should decrease a little each day. Increases in energy and activity are signs that recovery is going well. Maintaining a healthy attitude, a well-balanced diet, and getting plenty of rest are also great ways to speed up recovery.

What are the risks?
No surgery is without risks. General complications of any surgery include bleeding, infection, blood clots (deep vein thrombosis), and reactions to anesthesia. If spinal fusion is done at the same time as a discectomy, there is a greater risk of complications. Specific complications related to ACDF may include:

Hoarseness and swallowing difficulties

In some cases, temporary hoarseness can occur. The recurrent laryngeal nerve, which innervates the vocal cords, is affected during surgery. It may take several months for this nerve to recover. In rare case (less than 1/250) hoarseness and swallowing problems may persist and need further treatment with an ear, nose and throat specialist.

Vertebrae failing to fuse

Among many reasons why vertebrae fail to fuse, common ones include smoking, osteoporosis, obesity, and malnutrition. Smoking is by far the greatest factor that can prevent fusion. Nicotine is a toxin that inhibits bone-growing cells. If you continue to smoke after your spinal surgery, you could undermine the fusion process.

Hardware fracture

Metal screws, rods, and plates used to stabilize the spine are called hardware. The hardware may move or break before your vertebrae are completely fused. If this occurs, a second surgery may be needed to fix or replace the hardware.

Bone graft migration

In rare cases (1 to 2%), the bone graft can move from the correct position between the vertebrae soon after surgery. This is more likely to occur if hardware (plates and screws) are not used to secure the bone graft. It’s also more likely to occur if multiple vertebral levels are fused. If this occurs, a second surgery may be necessary.

Transitional syndrome (adjacent-segment disease)

This syndrome occurs when the vertebrae above or below a fusion take on extra stress. The added stress can eventually degenerate the adjacent vertebrae and cause pain.

Nerve damage or persistent pain

Any operation on the spine comes with the risk of damaging the nerves or spinal cord. Damage can cause numbness or even paralysis. However, the most common cause of persistent pain is nerve damage from the disc herniation itself. Some disc herniations may permanently damage a nerve making it unresponsive to decompressive surgery. Be sure to go into surgery with realistic expectations about your pain. Discuss your expectations with your doctor.

Infection

There is a small chance of wound infection. In very rare cases this can spread to the deep tissues and require further surgery to eradicate it. Signs of infection like swelling, redness or draining at the incision site, and fever should be checked out by the surgeon immediately.