It's Not Just for Hips & Knees: Cervical Disc Replacement

By: David L. Coran, MD

Orthopedic surgeons have been replacing hips and knees with artificial joints for several decades. More recently, artificial disc replacements became available for the cervical spine.

Just as hip and knee replacements provide patients with an excellent option for pain relief while preserving joint motion, artificial cervical discs offer a similar solution that orthopedic surgeons can offer for painful neck conditions.

Sources of Pain

The cervical spine is composed of bony building blocks: the vertebrae and the intervening shock absorbers, the discs. The spinal cord and nerves are located behind these structures in the spinal canal.

Conditions such as degenerative arthritis and disc herniations cause pain when they pinch the nerves or spinal cord. Pain can impact the neck and shoulders – radiating into the arms and hands – and cause headaches.

Radiating pain from a pinched nerve is called radiculopathy and can lead to numbness, tingling and weakness in the arms and hands. More serious problems occur when the spinal cord is compressed and myelopathy develops. Myelopathy may lead to difficulties with balance, coordination, and loss of strength in the arms and legs.

Relief is in Sight

Fortunately, most neck problems can be treated without surgery. Over 90 percent of patients can receive physical therapy, medications, and sometimes, epidural steroid injections. For the minority of patients with radiculopathy who do not improve with nonoperative care, and most patients with myelopathy, several surgical procedures have been successful in alleviating pain and neurological impairments.

Surgery can be done through the front of the neck or from the back of the spine. The anterior [front] approach is used in the majority of cases as it allows the spine surgeon excellent access to the painful disc and bone spurs that need to be removed. After the removal or decompression part of the procedure, the empty disc space needs to be filled with a structural support.

Fusion procedures have been used for over 50 years and use a bone graft or a cage. A metal plate with screws holds the fused level together until bone growth occurs and the fusion becomes permanent. The results of cervical fusion have been excellent. Usually, 95 percent of patients have reliable relief of symptoms. However, disadvantages include failure of the bone graft to incorporate, stiffness, and increased stress on the discs above and below the fused level.

Artificial disc replacement offers some advantages over the fusion. The metal and plastic disc does not require any bone graft. The artificial disc is designed to move, avoiding stiffness and potential stress on the adjacent levels.

Recent studies have shown slightly better outcomes with disc replacements over fusions. There are some cases, however, where fusions are still required.

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