Spinal Sphere Devices Should Be Class III, Panel Recommends

The Orthopedic and Rehabilitation Devices Panel of the Medical Devices Advisory Committee to The U.S. Food and Drug Administration (FDA) has recommended that in light of the lack of information on their effectiveness and the unreasonable risks for illness or injury, spinal sphere devices should be regulated as Class III devices that require premarket approval (PMA).

Spinal sphere devices are permanent spine implants made from metal or polymer (such as cobalt chromium molybdenum or polyetheretherketone) materials. The devices can range in diameter from 9.5 to 19 mm, and designed to be implanted between vertebral bodies from L3 to S1 to help stabilize and promote intervertebral body fusion following a discectomy. During an arthrodesis procedure, they’re used with a bone graft.

The panel, chaired by John Kelly, M.D., associate professor, orthopedic surgery, Hospital of the University of Pennsylvania’s Sports Medicine Center, Philadelphia, agreed with an FDA committee recommendation that spinal sphere devices meet criteria for a Class III designation, which is the FDA’s highest-risk category for medical devices.

The devices are considered preamendment devices because they were in commercial distribution before May 28, 1976, when the Medical Device Amendments became effective. They are currently unclassified devices and reviewed under the 510(k) premarket notification authority.

An FDA committee reviewed scientific information on the devices and determined that the devices met the two criteria for Class III designation: There is insufficient information to determine that general and special controls are sufficient to provide reasonable assurance of the safety and effectiveness of the device; and the device is life-supporting or life-sustaining, is for a use that is of substantial importance in preventing impairment of human health, or presents a potential unreasonable risk for illness or injury.

Health risks associated with the spinal sphere devices include device subsidence and migration, which could lead to pain, neurologic impairment, and the need for removal or revision.

Panel members agreed with the FDA committee that there is a lack of data to determine that general and special controls are sufficient to provide reasonable assurance of the safety and effectiveness of spinal sphere devices for use in arthrodesis procedures. There was also consensus among members that the risk for injury is unreasonable given the lack of probable benefit.

Anna Mazzucco, Ph.D., senior fellow, National Research Center for Women and Families, urged the panel to “agree with the FDA that these are high-risk life-sustaining devices that need to be tested in clinical trials to be sure they’re safe and effective.”

“Holding these implants to the higher standard, the PMA, will help reassure patients that these devices are proven to be beneficial,” she said. She pointed out that some devices are made with metal alloys, which may have high levels of cobalt and chromium and that in similar devices used in hip and knee implants have been linked to leukemia and kidney and prostate cancer.

However, Bernard A. Pfeifer, M.D., an orthopedic surgeon with offices in Concord and Burlington, Mass., and a nonvoting member of the panel, pointed out that extrapolating information related to articulating devices to seemingly non-articulating devices “may be a reach.”

The FDA will now consider the input from this panel before making a decision on classification for spinal sphere devices.