WEST COLUMBIA, South Carolina — Desperate for relief after years of agony, Jim Taft listened intently as his pain management doctor described a medical device that could change his life.

It wouldn't fix the nerve damage in his mangled right arm, Taft and his wife recalled the doctor saying, but a spinal-cord stimulator would cloak his pain, making him "good as new."

Taft's stimulator failed soon after it was surgically implanted. After an operation to repair it, he said, the device shocked him so many times that he couldn't sleep and even fell down a flight of stairs. Today, the 45-year-old Taft is virtually paralyzed, barely able to get to the bathroom by himself.

"I thought I would have a wonderful life," Taft said. "But look at me."

For years, medical device companies and doctors have touted spinal-cord stimulators as a panacea for millions of patients suffering from a wide range of pain disorders, making them one of the fastest-growing products in the $400 billion medical device industry. Companies and doctors push them as a safe antidote to the opioid crisis in the U.S. and as a treatment for an aging population in need of pain relief.

But the stimulators — devices that use electrical currents to block pain signals before they reach the brain — are more dangerous than many patients know, an AP investigation found. They account for the third-highest number of medical device injury reports to the Food and Drug Administration, with more than 80,000 incidents flagged since 2008.

Patients report they have been shocked or burned or have suffered spinal-cord nerve damage ranging from muscle weakness to paraplegia, FDA data shows. Among the 4,000 types of devices tracked by the FDA, only metal hip replacements and insulin pumps have logged more injury reports.

Medical device manufacturers insist spinal-cord stimulators are safe — some 60,000 are implanted annually — and doctors who specialize in these surgeries say they have helped reduce pain for many patients.

Most of these devices have been approved by the FDA with little clinical testing, however, and the agency's data shows that stimulators have a disproportionately higher number of injuries compared to hip implants, which are more plentiful.

The AP reported on spinal stimulators as part of a nearly yearlong joint investigation of the global medical devices industry that included NBC News, the International Consortium of Investigative Journalists and more than 50 other media partners around the world. Reporters analyzed millions of medical records, recall notices and other safety warnings, in addition to interviewing doctors, patients, researchers and whistleblowers.

The media partners found that, across all types of medical devices, more than 1.7 million injuries and nearly 83,000 deaths were reported to the FDA over the last decade.

The investigation also found that the FDA — considered by other countries to be the gold standard in medical device oversight — puts people at risk by pushing devices through an abbreviated approval process, then responds slowly when it comes to forcing companies to correct sometimes life-threatening products.

Devices are rarely pulled from the market, even when major problems emerge. And the FDA does not disclose how many devices are implanted in the U.S. each year — critical information that could be used to calculate success and failure rates.

The FDA acknowledges its data has limitations, including mistakes, omissions and under-reporting that can make it difficult to determine whether a device directly caused an injury or death. But it rejects any suggestion of failed oversight.

"There are over 190,000 different devices on the U.S. market. We approve or clear about a dozen new or modified devices every single business day," Dr. Jeffrey Shuren, the FDA's medical device director said at an industry conference in May. "The few devices that get attention at any time in the press is fewer than the devices we may put on the market in a single business day. That to me doesn't say that the system is failing. It's remarkable that the system is working as it does."

In response to reporters' questions, the FDA said last week it was taking new action to create "a more robust medical device safety net for patients through better data."

″Unfortunately, the FDA cannot always know the full extent of the benefits and risks of a device before it reaches the market," the agency said. In the last 50 years, the medical device industry has revolutionized treatment for some of the deadliest scourges of modern medicine, introducing devices to treat or diagnose heart disease, cancer and diabetes.

Medical device companies have "invested countless resources — both capital and human — in developing leading-edge compliance programs," said Janet Trunzo, head of technology and regulatory affairs for AdvaMed, the industry's main trade association.

At the same time, medical device makers also have spent billions to try to influence regulators, hospitals and doctors.

In the U.S., where drug and device manufacturers are required to disclose payments to physicians, the 10 largest medical device companies paid nearly $600 million to doctors or their hospitals last year to cover consulting fees, research and travel and entertainment expenses, according to an AP and ICIJ analysis of data from the Centers for Medicare & Medicaid Services. This figure doesn't include payments from device manufacturers like Johnson & Johnson and Allergan, which also sell other products.

On top of that, lobbying records show the top four spinal-cord stimulator manufacturers have spent more than $22 million combined since 2017 to try to influence legislation benefiting their overall business, which includes other devices.

In a case the previous year involving stimulators, Medtronic Inc. agreed to pay $2.8 million to settle Justice Department claims the company had harmed patients and defrauded federal health care programs by providing physicians "powerful" financial inducements that turned them into "salesmen" for costly procedures. Medtronic denied wrongdoing. "As a matter of policy, Medtronic does not comment on specific litigation," the company said in a statement. "We do stand behind the safety and efficacy of our Spinal Cord Stimulators and the strong benefits this technology provides to patients, many of whom have tried all other therapy options to no benefit."

Some doctors enthusiastically promote spinal-cord stimulators without disclosing to patients they've received money from medical device manufacturers. Some experts say doctors are not legally required to disclose such payments, but they have an ethical obligation to do so. Sometimes the money goes to the doctors' hospitals, and not directly to them.

As for Taft, he said he just wanted to get better, but he has lost hope.

"This is my death sentence," Taft said, stretched out beneath his bed's wooden headboard on which he's carved the words "death row."

"I'll die here," he said.

Dr. Steven Falowski holds a display of spinal cord stimulation equipment in Bethlehem, Pennsylvania on Oct. 4, 2018. Peter Banda / AP file

A generation ago, tens of thousands of women were injured by the Dalkon Shield, an intrauterine device that caused life-threatening infections. Consumer advocates demanded testing and pre-market approval of medical devices to prevent deaths and injuries associated with defective products.

So in 1976, Congress passed the Medical Device Amendments, a law meant to assure Americans that devices recommended by their doctors would do good and not harm.

Charged with carrying out the law, the FDA created three classes of medical devices. High-risk products like spinal-cord stimulators are designated to be held to the most rigorous clinical testing standards. But the vast majority of devices go through a less stringent review process that provides an easy path to market for devices deemed "substantially equivalent" to products already approved for use.

That process became the standard path to market for thousands of devices, including hip replacements implanted in tens of thousands of patients that would later be recalled because metal shavings from the devices made some people sick.

The AP found that the FDA has allowed some spinal-cord stimulators to reach the market without new clinical studies, approving them largely based on results from studies of earlier stimulators.

Spinal stimulators are complex devices that send electrical currents through wires placed along the spine, using a battery implanted under the skin.

The four biggest makers of stimulators are Boston Scientific Corp., based in Massachusetts; Medtronic, with headquarters in Ireland and the U.S.; Nevro, in Redwood California; and Illinois-based Abbott, which entered the market after its $23.6 billion purchase of St Jude Medical Inc.

St. Jude's application to go to market with its first stimulator contained no original patient data and was based on clinical results from other studies, while Boston Scientific's application for its Precision stimulator was based largely on older data, though it did include a small, original study of 26 patients who were tracked for as little as two weeks.

Once approved, medical device companies can use countless supplementary requests to alter their products, even when the changes are substantial.

For example, there have been only six new spinal-cord stimulator devices approved since 1984, with 835 supplemental changes to those devices given the go-ahead through the middle of this year, the AP found.

"It's kind of the story of FDA's regulation of devices, where they're just putting stuff on the market," said Diana Zuckerman, president of the National Center for Health Research, who has studied medical devices for nearly 30 years.

Medical device manufacturers have cited multiple industry-funded studies showing the effectiveness of spinal-cord stimulation in the treatment of chronic pain.

A 2016 study looking at different stimulation systems found "significant evidence" that they were "a safe, clinical and cost-effective treatment for many chronic pain conditions."

But Zuckerman noted that the more extensive studies came after the devices were being widely used on people.

"These patients are guinea pigs," she said.

FDA said in a statement that its decisions are "based on valid scientific evidence" that the devices are safe and effective.

Dr. Walter J. Koroshetz, director at the neurological disorders and stroke division at the National Institutes of Health, said trials for medical devices like spinal-cord stimulators are generally small and industry-sponsored, with a "substantial" placebo effect.

"I don't know of anyone who is happy with spinal-cord technology as it stands," Koroshetz said. "I think everybody thinks it can be better."

Dr. Steven Falowski holds an electrode for a spinal cord stimulator in Bethlehem, Pennsylvania on Oct. 4, 2018. Peter Banda / AP file

Every time Jim Taft walked into his pain management doctor's office, he would glance at the brochures touting spinal-cord stimulators — the ones with pictures of people swimming, biking and fishing.

Inside the exam room, Taft said, his doctor told him the device had been successful for his other patients and would improve his quality of life.

On lifetime worker's compensation after his right arm was crushed as he hauled materials for an architectural engineering company, Taft had been seeing the doctor for five years before he decided to get a stimulator in 2014. What finally swayed him, he said, was the doctor's plan to wean him off painkillers.

"I felt backed into a corner," said Taft.

Taft said his doctor praised the technology, saying stimulators had improved the quality of life for his patients. But four years later, Taft is unable to walk more than a few steps.

Taft is one of 40 patients interviewed by the AP who said they had problems with spinal-cord stimulators. The AP found them through online forums for people with medical devices. Twenty-eight of them said their stimulators not only failed to alleviate pain but left them worse off than before surgery.

Zuckerman, who worked at the Department of Health and Human Services and as a senior policy adviser to then-first lady Hillary Clinton, said no doctor wants to think they're harming patients.

"But there's a tremendous financial incentive to downplay, ignore or forget bad patient experiences and just focus on how happy patients are," she said.

More than half the patients interviewed by the AP said they felt pressured to get stimulators because they feared their doctors would cut off their pain medications — the only thing helping them.

Stimulators are considered a treatment of "last resort" by insurance companies, as well as Medicare and Medicaid. That means doctors must follow a protocol before insurance will pay for the device and implantation.

Physicians must show that conservative treatments failed to help. Patients also undergo psychological assessments to evaluate the likelihood of success. They then typically undergo a trial period lasting three days to a week with thin electrodes inserted under the skin. If patients say they got relief from the external transmitter sending electrical pulses to the contacts near their spines, they have surgery to implant a permanent stimulator.

Taft said his three-day trial helped reduce his pain so, a few days before his surgery, he began preparing for a new life. He ordered lumber to refurbish a patio and deck for his wife, Renee, as thanks for her years of support.

In April 2014, Boston Scientific's Precision stimulator was implanted in Taft by Jason Highsmith, a Charleston, South Carolina, neurosurgeon who has received $181,000 from the company over the past five years in the form of consulting fees and payments for travel and entertainment. A Boston Scientific sales representative was in the operating room — a common practice, the AP found.

Highsmith would not comment on the payments. Other doctors have defended the practice, saying they do important work that helps the companies — and ultimately patients — and deserve to be compensated for their time.

From the time Taft's device was placed inside his body, he had nothing but problems, according to hundreds of pages of medical records reviewed by the AP. The device began randomly shocking him, and the battery burned his skin.

Taft and his wife complained repeatedly, but said his doctors and a Boston Scientific representative told them stimulators don't cause the kind of problems he had.

That runs counter to Boston Scientific's own literature, which acknowledges that stimulators and the procedures to implant them carry risks, such as the leads moving, overstimulation, paralysis and infections.

That also is not reflected in the AP's analysis of FDA injury reports, which found shocking and burning had been reported for all major models of spinal-cord stimulators. For Boston Scientific devices, infection was the most common complaint over the past decade, mentioned in more than 4,000 injury reports.

In response to questions, the company called infection "unfortunately a risk in any surgical procedure" that the company works hard to avoid. It added that the FDA's data "shouldn't be interpreted as a causal sign of a challenge with our device. In fact, many examples of reportable infections include those that were caused by the surgical procedure or post-operative care."

"In our internal quality assessments, over 95 percent of the injury reports were temporary or reversible in nature," the company added.

Taft's stimulator was surgically removed in August 2015. The following June, Taft got a second opinion from a clinic that specializes in spinal injuries, which said he had "significant axial and low back pain due to implantation and explantation" of the stimulator.

Highsmith said other doctors have documented severe arthritis in Taft and that, while he has not examined Taft in more than three years, it's "likely his current condition is the result of disease progression and other factors."

He did not answer questions about whether he informed Taft of the risks associated with stimulators.

The doctor said the overwhelming majority of his stimulator patients gain significant pain relief.

"Unfortunately, in spite of the major medical breakthroughs with devices like these, some patients still suffer from intractable pain," he said.

Renee Taft, a paralegal, reached out to Boston Scientific in 2017, but said the company refused to help because her husband's stimulator had been removed and blamed Taft for his problems, also saying he had engaged in "rigorous physical activity" after surgery.

In the letter from the company's legal department, Boston Scientific also noted that federal law shielded manufacturers from personal liability claims involving medical devices approved by the FDA.

In response to questions from the AP, Boston Scientific again blamed Taft's "activity level" but didn't elaborate. The company also said other factors could contribute to his problems such as "hyperalgesia, a phenomenon associated with long-term opioid use which results in patients becoming increasingly sensitive to some stimuli."

Boston Scientific said it never received the stimulator that was implanted in Taft and so could not "conclusively identify" the cause of his problems. "Numerous factors can contribute to a patient's ongoing symptoms, from increased physical activity to the onset of pain in other areas," the company said.

Dr. Steven Falowski stands for a portrait in Bethlehem, Pennsylvania on Oct. 4, 2018. Peter Banda / AP file

While manufacturers and top FDA officials tout stimulators as a weapon in the battle against opioids, neurosurgeons like Steven Falowski are the front-line evangelists.

"Chronic pain is one of the largest health-care burdens we have in the U.S. It's more than heart disease, cancer and diabetes combined," Falowski said in an interview.

He referred AP to Pete Corby as one of his surgical patients who was helped by a spinal-cord stimulator.

Corby, who injured his back working as a movie stuntman, got the device more than two years ago and says that after some initial adjustments he hasn't had any further problems. He says he wouldn't trade the stimulator for opioids.

"I was actually buying them on the street ... a little like a druggie because I couldn't get them anymore" from his pain doctor, Corby said.

Falowski said opioids are good for acute pain, but were never meant to treat long-term chronic pain. For him, that's where stimulators come in.

If they're used early enough for pain, they can prevent people from going on opium-based pain killers, said Falowski, who speaks at neuromodulation conferences and teaches other doctors how to implant stimulators.

Since 2013, device manufacturers have paid Falowski — or St. Luke's University Health Network in Fountain Hill, Pennsylvania, where he works — nearly $863,000, including $611,000 from St. Jude or its new parent company, Abbott, according to the Centers for Medicare and Medicaid Services database. The payments range from consulting fees to travel and entertainment expenses.

Falowski said he has conducted research and done other work for manufacturers, adding, "The contracts with industry are with my hospital and not with me."

St. Luke's told the AP that it keeps the majority of the payments from device makers, but that Falowski "may receive a portion of these payments through his annual compensation."

Falowski said doctors do important work for medical device companies, and he has been involved in device development, education, clinical trials and research.

"You're trying to help patients and you realize as a physician by yourself you're not going to generate $200 million to make the next best implant for a patient and it's going to take a company to do that," he said. "So I think the important part in that relationship is transparency and disclosures."

Experts interviewed by the AP said doctors are not legally required to tell patients about financial relationships with medical device manufacturers, but that it would be the right thing to do.

"The patient should be fully informed before consenting to a procedure," said Genevieve P. Kanter, an assistant professor at the University of Pennsylvania who specializes in internal medicine, medical ethics and health policy.

Washington D.C.-based Associated Press reporters Meghan Hoyer and Matthew Perrone contributed to this report, as did Denver-based video journalist P. Solomon Banda.

This story is part of a global project organized by the International Consortium of Investigative Journalists to examine the medical device industry. More than 250 reporters in 36 countries, including reporters for NBC News and the AP, worked on stories that began publishing Sunday.