Artificial Disk Replacement (ADR)

Overview

Artificial Disk Replacement (ADR) is a procedure that helps improve lower back pain by replacing a damaged spinal disk with an artificial one. While the procedure may not completely eliminate pain, within the weeks and months following surgery lower back pain is usually improved without constricting spinal movement.

ANATOMY

The spine consists of 33 individual interlocking bones known as vertebrae. The vertebrae are categorized into five regions:

• Cervical
• Thoracic
• Lumbar
• Sacrum
• Coccyx

The primary function of the vertebrae in the lumbar region of the spine is to bear the weight of the body. To support all that weight, they are larger in size as compared to the other vertebrae.

Intervertebral disks sit between the vertebrae and act as shock absorbers for the spine. They are flat, round and about half an inch thick. They are made up of two components—the nucleus pulposus and the annulus fibrosus. The nucleus has a jelly-like consistency and is found in the center of the disk. The “jelly” allows the disk to be flexible and strong. The annulus is the flexible outer ring of the disk and consists of several layers.

When moving or standing, weight is put on the nucleus, causing it to expand while the annulus holds it in place. Together, the nucleus and annulus allow for movement to take place while simultaneously maintaining the strength of the spine. Many nerve endings surround the annulus and, as a result, an injured annulus can cause pain.

DESCRIPTION

Artificial Disk Replacement (ADR) is a procedure that helps improve lower back pain. During the procedure, the worn or damaged disk material between the small bones in vertebrae in the spine is removed and replaced with a synthetic or “artificial” disk. The goal of the procedure is to relieve back pain while maintaining a normal motion than allowed with some other procedures, such as spinal fusion.

Spinal fusion is a surgical technique that physically joins two or more vertebrae. While many patients are helped by this procedure, the results can vary. It is believed that poor spinal fusion results occur because the procedure prevents normal spine movement. ADR improves on this failure by maintaining a more normal spinal motion, which has been proven to cause better post-surgery results.

DIAGNOSIS

ADR is not meant for everyone. Your Florida Orthopaedic Institute physician will analyze your symptoms, looking for the following:

• Back pain caused by one or two problematic intervertebral disks in the lumbar spine.
• No significant facet joint disease or bony compression on spinal nerves.
• Body size that is not excessively overweight.
• No prior major surgery on the lumbar spine.
• No deformity of the spine (scoliosis).

Your physician may need a few tests to further decide if ADR is right for you. These tests include:

• Magnetic resonance imaging (MRI) scans
• Diskography
• Computed tomography (CT) scans
• X-rays

SURGICAL PROCEDURES/TREATMENTS

Before your procedure, your Florida Orthopaedic Institute physician will discuss the best disk design for you, as there are many different designs to choose from. In most cases, the disk replacement substitutes for both the annulus and nucleus, with a mechanical device that will simulate spinal function. Disks can be made of metal (medical grade cobalt, chromium or titanium alloy) or a combination of metal and medical grade plastic (polyethylene). Each design, while all different, maintains a similar goal – to reproduce the size and function of a healthy intervertebral disk.

During the procedure, an incision will be made in your lower back. This incision location means that the organs and blood vessels must be moved to the side, allowing your surgeon to access your spine without moving the nerves. The disk space is then opened and exposed, the problematic disk is removed, and the artificial disk is implanted in its place.

NEXT STEPS

In most cases, patients stay in the hospital for one to three days and are encouraged to stand and walk by the first day after surgery. Basic exercises, including regular walking and stretching, will need to be performed during the first several weeks after surgery to ensure a smooth recovery. During this time, any activities that cause the back to hyperextend should be avoided. Most patients will experience pain improvement in the weeks to months following surgery, but the complete elimination of lower back pain is not a guarantee.

If you are experiencing back pain, contact one of the fellowship trained physicians at Florida Orthopaedic Institute for a consultation.