The U.S. approved potentially dangerous types of medical implants called “spinal cord stimulators” based on faulty science and poorly designed studies, according to a new report from the consumer rights group Public Citizen.

The report, released Wednesday, accuses the Food and Drug Administration, which oversees medical devices,  of “dangerously subverting” the usual regulatory process in order to more easily get stimulators to market.

The devices, implanted next to the spine as a treatment for chronic pain, were approved with less vigorous testing than required of similar invasive devices.

These deficiencies have resulted in serious injury to tens of thousands of patients – Michael Carome

Doctors say the implants have helped numerous patients escape chronic pain. But, as the Associated Press report notes, the stimulators have also been linked to patients suffering burns, shocks and other injuries that have resulted in paralyzation and even death.

Public Citizen notes that clinical trials were not required in some cases. The report warns that poorly tested spinal cord stimulators can seriously injure or even kill patients who may not be well informed of the risks they pose.

“These deficiencies have resulted in serious injury to tens of thousands of patients,” Michael Carome, the director of Public Citizen’s Health Research Group, told the International Consortium of Investigative Journalists. “That current federal law allows the FDA to approve such high-risk devices without any clinical testing in humans to ensure that the devices are safe and effective should trouble all Americans.”

In a statement, the FDA told ICIJ that it is reviewing the Public Citizen report but stands by the safety of the devices.

Public Citizen’s report was prompted by the Implant Files, an ICIJ reporting collaboration into the medical device industry that found regulators around the world had bent to pressure from medical device companies to quickly approve risky implants with little or no testing in humans. The investigation showed that companies were slow to stop selling flawed devices even as injuries mounted and patients are often left in the dark over recalls of faulty products implanted inside their bodies.

The Associated Press, an ICIJ partner, reported that spinal cord stimulators, which are marketed to help relieve chronic pain, are more dangerous than many patients understand. The devices accounted for the third highest number of injuries and deaths recorded in an FDA database, with 80,000 incidents involving the devices having accumulated between 2008 and 2018, according to the AP.

Building on the AP’s reporting, Public Citizen’s report digs deep into a troubled regulatory process that began in 1978 with early models of the stimulators being categorized as Class II, or medium-risk – the same classification as a wheelchair or pregnancy test – causing the early stimulator versions to avoid stringent testing and scrutiny requirements, according to the report.

Although the FDA later began classifying the fully implanted versions of the devices as Class III, or the highest risk category, the FDA appeared to continue regarding the stimulators as needing little scrutiny, the report says.

The FDA allowed a lax standard of evidence for safety and effectiveness, allowing new devices to be cleared without human testing, the report says. Instead the agency relied on studies examining older devices — a controversial practice that is supposed to be confined to lower risk products.

The FDA also “inexcusably misused” a separate approval pathway meant for modifications to existing devices in order to clear entirely new models of spinal cord stimulators, the report alleges. In addition to arguing that the scale of the changes were inappropriate for that pathway, Public Citizen says that the agency has also cloaked the data behind those decisions in secrecy, not providing the public with any means to evaluate the rationale for the approvals. “Documents describing the full nature of the changes, the evidence to support the changes, and the FDA’s rationale for approval, with one exception out of several hundred, have not been made publicly available on the agency’s website,” the report states.

The FDA defended its record with the devices, but did not directly address Public Citizen’s assertion that the agency approved devices based on data from separate products. “In total, there is clinical evidence based on thousands of patients that the devices are safe and effective at relieving pain in appropriately selected individuals,” Kristin Jarrell, a spokesperson for the FDA told ICIJ in an email. “The FDA has carefully reviewed the adverse event reports, including death reports, associated with spinal cord stimulators and continues to monitor their safety. ”

Jarrell noted that device-related complaints do not necessarily mean that a faulty device was the root of a bad outcome for a patient.

Public Citizen is calling on the FDA to implement a series of changes to the way it regulates both stimulators and medical devices at large. The report urges the agency to take immediate action to reclassify spinal cord stimulators from medium-risk to high-risk, and to more broadly reassess the safety of all implanted spinal cord stimulators. Public Citizen also says that the FDA must publicly list high-risk devices that were approved based on literature about other devices, and says that Congress must conduct hearings to strengthen the FDA’s oversight of medical devices.