Scott Graham is a senior writer covering California appellate litigation for The Recorder, an American Lawyer affiliate.

A state law tort claim of failure to warn about risky medical devices is not pre-empted by the federal medical device law — so long as the state law duty of care runs “parallel” to a duty established by the federal law.

That brain-twisting holding Thursday by an en banc panel of the U.S. Court of Appeals for the Ninth Circuit could expose manufacturers of hundreds of high-risk medical devices to hefty state tort damages.

The ruling in Stengel v. Medtronic is a win for plaintiffs and for Judge John Noonan, who dissented from a panel decision last year finding pre-emption. The en banc decision adopting Noonan’s point of view was unanimous, though Judge Paul Watford penned a concurrence suggesting that plaintiffs Richard and Mary Lou Stengel may have won a Pyrrhic victory.

Richard Stengel had Medtronic’s SynchroMed EL Pump and Catheter surgically implanted in his abdomen in 2000 to deliver pain relief medication directly to his spine. Five years later he collapsed in his home and was diagnosed with ascending paralysis in his lower body. Stengel alleges that Medtronic’s pump caused the paralysis, which is permanent. He further claims that Medtronic learned of the risk after the pump was approved by the Food and Drug Administration in 1999, but before he became paralyzed. Because the SynchroMed pump is a Class III medical device–the most risky type–Medtronic had a duty to report any newly discovered risks to the FDA, according to Stengel and his attorney, Thomas Cotter of Tucson, Ariz.

A Ninth Circuit panel led by Judge J. Clifford Wallace ruled in 2012 that Stengel’s claim was pre-empted by the federal Medical Device Amendments to the Food, Drug, and Cosmetic Act, as interpreted by a 2001 U.S. Supreme Court decision, though Wallace acknowledged a circuit split on the issue.

Noonan dissented, saying it was “astonishing” to think that Congress would have intended to exempt manufacturers of dangerous medical devices from tort liability.

On Thursday a unanimous en banc court led by Judge William Fletcher sided with Noonan. The Supreme Court precedent involved fraud in the FDA approval process, Fletcher wrote, whereas the Stengels’ claim alleges the failure to report problems discovered after FDA approval.

“Plaintiffs’ claim is brought under settled Arizona law that protects the safety and health of Arizona citizens by imposing a general duty of reasonable care on product manufacturers,” Fletcher wrote.

Because that same duty of care–albeit with lesser remedies — is included in the Medical Device Amendments, there is no pre-emption, Fletcher concluded. The Fifth and Seventh circuits have reached the same conclusion, he added.

In his concurring opinion, Watford wrote that by fashioning their claim to avoid pre-emption, the Stengels had created “a causation hurdle.”

“To prevail, they will ultimately have to prove that if Medtronic had properly reported the adverse events to the FDA as required under federal law, that information would have reached Mr. Stengel’s doctors in time to prevent his injuries,” wrote Watford, who was joined by six other judges. “But at this juncture–a request for leave to amend their complaint–the Stengels’ allegations of causation are adequate.”Michael Brown of Reed Smith argued the appeal for Medtronic.