How the FDA Approved Spinal Cord Stimulators

The federal lawsuits against Abbott and Boston Scientific do not simply allege that their spinal cord stimulators caused injuries. They allege that the devices were never properly tested in the first place — that the FDA's own regulatory process allowed manufacturers to introduce fundamentally redesigned products without requiring the clinical evidence that the law is supposed to demand for high-risk implantable devices.

What Is Premarket Approval (PMA)?

Premarket Approval is the FDA's most stringent regulatory pathway for medical devices. It applies to Class III devices — those that support or sustain human life, are of substantial importance in preventing impairment of human health, or present a potential unreasonable risk of illness or injury. Spinal cord stimulators are classified as Class III devices.

Unlike the more common 510(k) clearance process, which allows manufacturers to market a new device by demonstrating that it is "substantially equivalent" to one already on the market, PMA requires the manufacturer to submit valid scientific evidence — typically including data from clinical trials in human patients — demonstrating that the device is safe and effective for its intended use. The FDA has stated that PMA is "the most stringent type of device marketing application required by FDA."

The PMA process is expensive and time-consuming by design. It costs manufacturers an average of approximately $94 million to bring a device to market through PMA, compared to $31 million through the 510(k) pathway. The FDA spends an average of 1,200 hours reviewing a single PMA application, and the process from submission to approval typically takes one to three years. Fewer than 5 percent of medical devices reach the U.S. market through the PMA process — the vast majority use the less rigorous 510(k) route.

This rigor exists because the consequences of failure in a Class III device are severe. A spinal cord stimulator that malfunctions is not a device that can simply be stopped and swapped. Its leads are threaded into the epidural space surrounding the spinal cord. Its pulse generator is surgically implanted under the skin. Correcting a problem may require additional invasive surgery, and in some cases, the damage may be irreversible.

How SCS Devices Were Originally Approved

Both Abbott's and Boston Scientific's spinal cord stimulator product lines trace their FDA approvals to the early 2000s. According to the pending federal lawsuits, neither original PMA was supported by clinical studies submitted by the manufacturer that tested the actual device being approved.

Abbott: Genesis SCS — PMA P010032 (2001)

Abbott's Genesis spinal cord stimulator received PMA approval in 2001. The lawsuits allege that the original PMA was not based on clinical trials of the Genesis device itself. Instead, the FDA granted approval based on published literature — studies that had been conducted on other manufacturers' spinal cord stimulators. The plaintiffs contend that this meant the Genesis was approved based on data from devices with different designs, different components, and different manufacturers, rather than on direct evidence that the Genesis itself was safe and effective.

Boston Scientific: Precision SCS — PMA P030017 (2004)

Boston Scientific's Precision spinal cord stimulator received PMA approval in 2004. Like the Abbott Genesis, the lawsuits allege that the Precision's PMA was granted without manufacturer-submitted clinical studies of the actual Precision device. The FDA's approval letter for the Precision confirmed that the device was indicated as an aid in the management of chronic intractable pain of the trunk and limbs, including pain associated with failed back surgery syndrome.

PMA Supplements: The Regulatory Shortcut

Once a device receives PMA approval, the manufacturer must submit a PMA supplement to the FDA before making any change that could affect the device's safety or effectiveness. This is a legal requirement under 21 CFR 814.39. Supplements are intended to cover modifications to an already-approved device — not to serve as a pathway for introducing an entirely new product under the same PMA number.

The distinction between a full PMA application and a PMA supplement is significant. A full PMA typically requires clinical trial data, takes years to complete, and costs tens of millions of dollars. A PMA supplement generally does not require new clinical trials, involves a shorter review period, and allows the manufacturer to continue selling the device while the supplement is under review.

The problem, according to the plaintiffs and regulatory critics, is that manufacturers used serial PMA supplements — one after another, over many years — to introduce changes so substantial that the resulting devices bear little resemblance to the products that originally received PMA approval. Each individual supplement may have described the change as incremental or limited in scope. But taken together, the lawsuits allege, the cumulative effect was to create entirely new devices that were never subjected to the clinical testing a full PMA would have required.

A study of approvals for cardiac implantable electronic devices — a comparable category of Class III implants — found that for every approved PMA, an average of 50 PMA supplements were subsequently approved, and that most new device models were deemed safe and effective without any new clinical data. The spinal cord stimulator space appears to have followed a similar pattern.

What Changed in the Devices

The changes introduced through PMA supplements were not cosmetic or minor. According to the lawsuits and publicly available regulatory documents, the modifications introduced to Abbott's and Boston Scientific's spinal cord stimulator lines since their original approvals include:

New stimulation waveforms and frequencies. The original approved devices delivered traditional tonic (low-frequency) stimulation. Subsequent models introduced high-frequency stimulation (up to 10,000 Hz), burst stimulation, and closed-loop adaptive stimulation — fundamentally different approaches to how electrical energy is delivered to the spinal cord. These new modes of operation alter the interaction between the device and the patient's nervous system.

Redesigned lead systems. Lead configurations, electrode counts, electrode spacing, and lead body designs were modified across device generations. The leads are the components placed directly in the epidural space next to the spinal cord — changes to their design directly affect where and how electrical stimulation is delivered, as well as the risk of complications like migration and fracture.

Updated battery and power architecture. Pulse generators were redesigned with new battery chemistries, rechargeable systems, and different power management profiles. Battery-related issues — including premature depletion, overheating, and charging failures — have been a persistent source of adverse event reports and recall actions.

Wireless communication and software control. Newer generations introduced Bluetooth-enabled patient controllers, smartphone apps for device programming, and wireless firmware update capabilities. The 2023 Class I recall of Abbott's Proclaim and Infinity devices was directly caused by a failure in the Bluetooth communication system that left patients unable to restore therapy after MRI scans.

Expanded electrode arrays and multi-source current delivery. Device generations increased the number of independently programmable electrodes and introduced the ability to deliver stimulation from multiple current sources simultaneously. These changes affect the specificity and intensity of spinal cord stimulation.

The lawsuits argue that these modifications — taken individually or collectively — constitute changes that should have required new PMA applications with clinical trial data, not PMA supplements that relied on bench testing, engineering analysis, and literature reviews.

The Preemption Problem

The regulatory approval process for spinal cord stimulators is not only relevant as background to the litigation — it is a central legal issue that will shape whether the cases can proceed at all. The reason is a legal doctrine called federal preemption.

In 2008, the U.S. Supreme Court held in Riegel v. Medtronic, Inc. (552 U.S. 312) that the Medical Device Amendments to the Federal Food, Drug, and Cosmetic Act preempt — that is, override — most state common-law tort claims against manufacturers of Class III medical devices that have received PMA approval. The Court's reasoning was that the PMA process establishes federal requirements for the device, and state-law claims seeking to impose additional or different requirements are barred.

In practical terms, this means that a patient who is injured by a PMA-approved device generally cannot sue the manufacturer under state product liability law for design defects, failure to warn, or breach of warranty — because the FDA has already reviewed and approved those design and labeling elements. The preemption defense has been described by legal commentators as one of the most significant obstacles to medical device litigation.

How the SCS Lawsuits Navigate Preemption

The pending spinal cord stimulator lawsuits attempt to overcome the preemption defense through two primary legal strategies:

Parallel claims. While Riegel held that state-law claims imposing requirements "different from, or in addition to" federal requirements are preempted, the Court left open the possibility that claims based on alleged violations of federal requirements themselves — so-called "parallel claims" — could proceed. The SCS plaintiffs allege that the manufacturers violated the FDA's own requirements by using PMA supplements to introduce changes that were so substantial they should have required full PMA applications. If the devices on the market today are not, in fact, the devices that received PMA approval, the plaintiffs argue, then the preemption defense does not apply — because the currently marketed devices were never properly approved.

Administrative Procedure Act claims against the FDA. In an unusual legal strategy, the SCS lawsuits name the FDA itself as a defendant and raise claims under the Administrative Procedure Act (APA), alleging that the agency's decision to approve PMA supplements for these substantial device modifications was "arbitrary and capricious" under the APA's standard of review. This is distinct from the product liability claims against the manufacturers and reflects the plaintiffs' argument that the regulatory process itself was legally deficient.

APA Claims Against the FDA

Naming the FDA as a defendant in a medical device lawsuit is uncommon. Federal agencies are generally protected from tort liability by sovereign immunity. However, the Administrative Procedure Act provides a narrow pathway for challenging federal agency actions that are alleged to be "arbitrary, capricious, an abuse of discretion, or otherwise not in accordance with law" under 5 U.S.C. § 706(2)(A).

The SCS plaintiffs allege that the FDA acted arbitrarily and capriciously by approving PMA supplements that allowed manufacturers to introduce major device redesigns without requiring new clinical evidence. The legal theory is that the FDA's own regulations require supplements to be limited to modifications that do not fundamentally alter the device — and that the agency violated its own standards by treating substantial changes as routine modifications.

This legal strategy is not without challenges. The APA's standard of review is deferential to agency decision-making, and courts have historically been reluctant to second-guess the FDA's technical judgments about what constitutes a "substantial" change to a medical device. Additionally, APA claims do not result in monetary damages — they can result in court orders requiring the agency to reconsider its decisions, but not in the kind of compensatory awards available in product liability lawsuits.

However, the APA claims serve a broader purpose in the litigation. If a court were to find that the FDA improperly approved PMA supplements for spinal cord stimulators, that finding would directly undermine the manufacturers' preemption defense. A device whose approval is found to be legally deficient cannot claim the protections that come with proper PMA approval. In this way, the APA claims and the product liability claims against the manufacturers are strategically linked.

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