Screws-Medical, Surgical, Bone etc.

To Screw or Not to Screw: The Pedicle Question

Common Back Surgery Device Not FDA Approved
Most chiropractors saw or know of the segment aired by ABC's "20/20" on chiropractic pediatrics, but may have missed the program's mid-December report on the use of pedicle screws in back surgery.

Orthopedic screws, which in the past were used to repair bones in the arms and legs, are now being used in the majority of the tens of thousands of spinal stabilization procedures performed every year in the U.S. The screws, which are permanently fixated in most cases, are being used to treat everything from low back pain to degenerative spondylolisthesis.

Chiropractors who cringe at the thought of such invasive solutions to back problems are not alone. The Food and Drug Administration (FDA), under the Department of Health and Human Services, has not approved the use of pedicle screws on the spine. While the FDA has allowed their use in clinical studies, they have not authorized broader usage. The FDA has declared: "Their safety and effectiveness for spinal surgery have not been established by the manufacturers."

How has the use of pedicle screws in spinal surgery grown to such an extent without FDA sanction? North American surgeons in the mid-1980s, inspired by the results of pedicle screw use in Europe, saw the screws as a better way to fixate the spine.1 Orthopedic surgeon Arthur Steffe of Cleveland, Ohio, "spearheaded" the use of the screws. Dr. Steffe also happens to be chairman of a company that markets the devices.

Below are excerpts from the FDA's public health service announcement on pedicle screws:2

Question: How are the screws used?

FDA Response: A pair of the screws is placed horizontally into the rear of the bony bridges, called pedicles, that are connected to each vertebra, one on each side. Vertical rods (or plates) are attached to the screws. The rods are connected to the pedicles of a second vertebra by means of another set of pedicle screws, straightening or strengthening the spine.

Question: Why is FDA concerned about the screws?

FDA Response: Because, despite their widespread use, not enough is known about the possible short-term adverse effects of the screws when they are used in the pedicles of the spine, nor about their long-term effectiveness. Under the law, before orthopedic screws can be marketed as pedicle screws, their manufacturers must submit scientific data to FDA establishing that these devices are safe and effective for this purpose. Limited studies of pedicle screws have been ongoing for a number of years, and FDA has approved using the screws in these studies. But the studies are still not complete, and the manufacturers have not yet accumulated enough data to show, one way or the other, whether the screws are safe and effective.

Question: How widespread is this use?

FDA Response: Pedicle screws have largely replaced other methods of spine stabilization such as wires, rods and hooks in the 30-70,000 spine stabilization procedures performed annually in the U.S. About 300,000 people have been implanted with the screws.

Question: If pedicle screws aren't approved, how can they be used so widely?

FDA Response: To encourage surgeons to use orthopedic screws in the pedicles of the spine, some manufacturers have been promoting this practice through professional advertising and training courses. This type of promotion is illegal.

Question: What is FDA doing about this illegal promotion?

FDA Response: On August 11, FDA warned the manufacturers to stop promoting the use of their orthopedic screws in the spine or face possible regulatory action, which could include seizure of their products, injunction or civil penalties. In addition, FDA is planning to require that manufacturers include in the labeling for the screws a statement that they are not approved for use in the spine.

Question: Does the lack of FDA approval mean the screws are unsafe?

FDA Response: Not necessarily. We simply don't have enough scientific data at this point to say for sure whether the screws are safe for use in the pedicles of the spine or not. There is some evidence that the screws might be beneficial in treating certain specific conditions, such as spinal fractures, degenerative spondylolisthesis (slippage of the spine), tumors, and scoliosis (spinal curvature). Even for these uses, however, there is not enough data to be certain.

Question: What about the problem of screws breaking inside the body?

FDA Response: Although some news stories have implied that the screws break very commonly, the actual breakage rate is not known. Limited information suggests that the screws now being used break less frequently than those used in the mid-1980s, because of improvements in product design and testing. More information is needed about breakage rates before FDA can decide whether the screws are safe and effective for use in the spine.

Question: In the meantime, what about people contemplating back surgery?

FDA Response: Patients considering back surgery in which pedicle screws might be used to stabilize the spine should keep in mind that these devices have not been approved for this purpose, and that FDA cannot assure that they are safe and effective. They should also remember that there is little evidence that the screws are effective in treating low back pain or simple disc problems. Patients should ask their doctors to explain beforehand both the potential benefits and risks of the screws, as well as alternative treatments, including nonsurgical ones.

No screws have been approved for use in the pedicles of the spine. The effectiveness of the screws -- or any other surgical procedure -- in treating low back pain or simple disc problems is uncertain.

Question: How about people who already have the screws?

FDA Response: People can report to FDA about problems with their pedicle screws by calling 1-800-FDA-1088. When the list of options is presented, choose number 3 if you wish to report a concern with a medical device.

Editor's note: Imagine the malpractice potential: 300,000 spine surgeries using a device that has not been approved by the FDA. This only serves to once again underscore the value and safety of conservative care.

References

1. The pedicle screw controversy. The Spine Letter, vol. 1, num. 1, March 1994.
2. Update on pedicle screws. Public health service announcement, FDA. Department of Health and Human Services, December 21, 1993.

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