Artificial Disc Replacement (ADR)
Artificial disc replacement at a glance
- Artificial disc replacement is a surgical procedure to remove and replace a degenerating spinal disc with an artificial disc implant that helps the spine retain its natural flexibility.
- Artificial disc replacement can be done on the lower back (lumbar spine) or on the neck (cervical spine).
- Artificial disc replacement is a potential alternative to spinal fusion surgery to reduce chronic back pain.
- Candidates for artificial disc replacement may be people with degenerative disc disease and/or those who have not responded to non-surgical procedures.
- Primary benefits of artificial disc replacement are reduced back pain and improved mobility.
- Potential complications of artificial disc replacement are allergic reactions to implanted materials or anesthesia, blood restriction or clotting, spinal cord injury or loosening of implants.
What is artificial disc replacement?
Artificial disc replacement (ADR) is a surgical procedure that involves implanting an artificial disc composed of metal and plastic into the spine to replace the degenerating disc. ADR can be performed on discs of the lumbar area of the lower back or on cervical discs in the neck area of the spine.
ADR helps relieve chronic lower back or neck pain caused by a degenerating spinal disc. The spinal discs are compressible structures located in between the bones of the spine that act as spacers, shock absorbers and motion units that allow the spine to flex, rotate and bend. The goal of the artificial disc is to imitate the usual form and function of the spinal discs.
This procedure is fairly new in the United States, but has been practiced in Europe for many years. The U.S. Food and Drug Administration (FDA) approved the use of artificial disc replacements in October 2004. A variety of artificial discs are being tested in clinical trials by the FDA to be approved for use. While all differ in design and material, they all aim to effectively replace degenerating discs in the spine.
Since ADR is new to the U.S., spinal fusion surgery is still much more prevalent. Spinal fusion surgery is a procedure to join or fuse two or more spinal discs. Spine surgeons believe that ADR can significantly improve back problems for many patients instead of performing spinal fusion. About 200,000 spinal fusion surgeries are performed each year in the U.S. The potential benefits of ARD over spinal fusion surgery include:
- Retention of spinal mobility
- Limited stress on adjacent discs
- Decreased risk of developing problems in areas alongside the spine
- Restoration of disc space height and reduction of pain.
However, artificial disc replacements have the potential to wear out over time and require subsequent surgeries. A thorough discussion with an orthopedic surgeon is required to determine the best possible procedure for each individual.
Indications and contraindications for artificial disc replacement
Indications for ADR will vary for each patient and their type of implant. Some general indications include:
- Diagnosis of degenerative disc disease
- Pain from a degenerative disc that has not responded to non-surgical procedures such as physical therapy, manual manipulation, medications and/or injections.
A patient may not be a good candidate for artificial disc replacement if one or more of the following contraindications exist:
- Osteoporosis (a condition in which bones become weak and brittle)
- Bone disease or infection
- Problems affecting the circulatory system
Artificial disc replacement surgery
Cervical ADR is usually performed on patients with a herniated cervical disc, which means the core of the disc leaks out (herniates) and presses on the nearby nerve root, causing debilitating pain in the neck and down the arm due to pinched nerves. This usually occurs due to injury to the neck, and is experienced mostly by people 30-50 years old.
A cervical ADR involves surgical removal of an intervertebral disc to decompress the spinal cord. The artificial disc is inserted in place of the removed disc that was between the two cervical vertebrae.
Lumbar ADR, the more common of the two ADR procedures, is performed through an incision in the abdomen. The surgeon moves organs and blood vessels aside to access the spine without having to move the nerves. He or she opens the disc space, removes the degenerated disc and replaces it with an artificial disc.
The surgery usually takes two to three hours. Patients are generally encouraged to stand and walk the day after surgery, and to soon move their trunk area, which can help in recovery. Patients generally stay in the hospital for two to four days. Rehabilitation exercises are ongoing, and patients can expect improved mobility and decreased pain within weeks or months of the surgery.
Risks of artificial disc replacement
As with any surgery of the spine there are risks and side effects. Potential complications associated with ADR include:
- Allergic reaction to implanted materials
- Implants loosening or moving
- Nerve or spinal cord injury
- Infection, either local or bodily
- Blood flow restrictions or blood clots
- Reactions to anesthesia.
There is also a risk that the procedure will not be effective for the patient and may not reduce or relieve preoperative symptoms.