Patient Information

Artificial Lumbar Disc

August, 2007

FDA-Approved Artificial Lumbar Discs

The CHARITÉTM artificial disc, a product of DePuy Spine, a Johnson & Johnson company, was the first approved by the Food and Drug Administration (FDA) in October 2004. The CHARITÉ disc is indicated for spinal arthroplasty in skeletally mature patients with degenerative disc disease at one level from L4 to S1. The mobile-core design consists of a sliding plastic core between two chrome plates.

The ProDiscTM-L Total Disc Replacement, a product of Synthes Spine, was approved by the FDA in August 2006. The ProDisc-L is indicated for spinal arthroplasty in skeletally mature patients with degenerative disc disease at one level from L3 to S1. The fixed-core ball and socket design consists of three implant components – two chrome endplates and a plastic inlay.

Artificial Disc Surgery

Artificial lumbar disc surgery is an alternative to spinal fusion surgery, a common operation performed on about 200,000 people a year with degenerative disc disease in the lumbar spine (lower back). Spinal fusion surgery creates a solid union between two or more vertebrae to help strengthen the spine and alleviate chronic back pain. There are many types of spinal fusion surgery, as well as varied instrumentation used to secure the fusion. The spine is accessed either through the back or abdomen, depending on the type of spinal fusion procedure.

The goals of artificial lumbar disc surgery are to: 1) Remove the diseased disc; 2) Restore normal disc height; 4) Decrease discogenic back pain; 4) Preserve motion in the affected vertebral segment; and 5) Improve patient function. In comparison to spinal fusion surgery, potential benefits of artificial disc technology may include quicker recovery time, more spine mobility after surgery, less stress on adjacent discs, and no need to harvest and use a bone graft.

To be considered a candidate for artificial lumbar disc surgery, you must meet the following specific criteria:

  • Disc degeneration in only one disc in the lumbar spine, between L4 to S1 or L3 to S1.
  • A minimum of six months of conservative treatment, such as physical therapy, pain medication, or back bracing, without showing improvement.
  • Overall good health with no signs of infection, osteoporosis or arthritis.
  • No known allergies to cobalt, chromium, molybdenum, polyethylene or titanium.

If you have degeneration affecting more than one disc or significant leg pain, you are not a candidate for this surgery. However, you may still be considered a candidate if you have had prior back surgeries.

During surgery, the patient is under general anesthesia and an incision is made in the abdomen. Through this opening, the affected disc is removed and replaced. The average hospital stay postoperatively is about four days. Since the CHARITÉ device was approved by the FDA, several thousand of these surgeries have been performed in the United States. To date, about 15,000 CHARITÉ devices have been implanted worldwide. Statistics are not yet available on the number of surgeries performed with the ProDisc-L device.

Potential Complications

Need for additional surgery
Allergic reaction to the implant materials
Bladder problems
Bleeding; may require a blood transfusion
Blood vessel problems other than bleeding
Death
Implants that bend, break, loosen or move
Incision problems
Infection
Male sexual dysfunction
Pain or discomfort
Paralysis
Phlebitis
Pneumonia
Side effects from anesthesia
Slow intestinal movement>
Spinal cord or nerve damage
Spinal fluid leakage
Tears of the dura (a layer of tissue covering the spinal cord)
Vertebrae fracture

Outcome

Some of the potential risks of artificial disc surgery are common to many other types of surgery, in particular back surgeries. Although some patients who have undergone spinal fusion surgeries need revision surgeries, they are generally less problematic than those after artificial disc surgery. There is still much debate among the medical community about the efficacy of artificial lumbar disc surgery.

In several documented cases, the artificial disc slipped out of place for undetermined reasons, which is a significant cause for concern. When this occurs, the patient may need emergency surgery to remove the disc, and the surgery can be life-threatening due to the potential for blood loss and other complications.

Load-bearing implants that allow motion have been shown to potentially generate wear debris over time. The long-term effects of wear debris on the spine are currently unknown. Preliminary comparative biomechanical data between the CHARITÉ and ProDisc-L indicate that the mobile-core design of the CHARITÉ may equate to a longer lifespan for the replaced disc due to reduced facet loading.

A March 2007 study analyzing the efficacy on 108 patients implanted with the CHARITÉ device in France between 1989 and 1995 appears promising. Patients were followed for a minimum of 10 years and up to 16.8 years with a majority reporting a decrease in pain and an increase in mobility. The overall rate of revision surgery was 10.4 percent, which included eight index-level fusion procedures and three prosthesis replacements.

Long-term patient monitoring is essential to properly assess how effective and safe artificial disc surgery is in comparison to spinal fusion surgery. While the artificial disc is groundbreaking, new technologies are in the pipeline that may have the potential to improve upon this surgical technique.

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