SUNNYVALE — When Teresa Hershey was told she needed a hysterectomy, her doctor recommended a novel approach: an operation performed by a robot, guided by the surgeon.

“She was just very persuasive,” said Hershey, 45. “I’d never heard of it.”

The doctor’s assertion that less invasive, robot-assisted surgery would mean seven to 10 days of recovery instead of six to eight weeks for a conventional operation convinced her, along with the prospect of less scarring: The da Vinci robots from Sunnyvale’s Intuitive Surgical need only small holes for inserting surgical equipment.

Now, seven years and 10 corrective surgeries later, Hershey is gearing up to fight Intuitive in Santa Clara County Superior Court. She says she has refused the firm’s offers to settle.

“I want to go all the way,” said Hershey, whose case would be only the third to go to trial amid a torrent of legal claims. “There’s just been too much with this company, and too many people hurt. I just want the world to know what they’ve done. I don’t want them to get away with it, to be swept under a rug.”

Since the da Vinci surgical robot received FDA approval in 2000, Intuitive’s devices — which are operated by a surgeon using joysticks, foot pedals and a 3-D viewer — have propelled the firm to a $35 billion valuation and world dominance in robot-aided surgery. But the legal claims that have come with Intuitive’s success showcase the serious risks that accompany the rewards new medical technology can bring.

Any kind of surgery carries risk: In high-income countries such as the United States, post-operative complications occur in up to 20 percent of all surgery patients, according to the U.S. National Institutes of Health. Proponents say the benefits of da Vinci systems are clear: They can be more precisely controlled, need smaller incisions, and lead to less blood loss and quicker recoveries.

In a 2014 regulatory filing, Intuitive said it was facing 3,000 product-liability claims over surgeries taking place between 2004 and 2013 when its robots performed about 1.7 million procedures. The firm set aside $67 million to settle an undisclosed number of claims. Many of the early claims related to device components that ended up being recalled by Intuitive. Product liability claims can allow consumers alleging harm to negotiate a settlement with a company without filing a lawsuit and Intuitive notes that such claims are “inherent to the medical device industry.” Its da Vinci machines have been used in more than 4 million operations.

In its most recent quarterly report, the firm said it is still facing a “large number” of product-liability claims, plus 52 lawsuits alleging its machines were responsible for patient injury or death, and a multiparty suit covering 55 patients who had da Vinci Surgeries in 22 different states. Many complaints concern surgeries done in 2012 and 2013.

“Robotic-assisted surgery is an important surgical option that is safe and effective when used appropriately and with proper training,” the company said in a statement to this news organization.

“There are more than 13,000 peer-reviewed publications examining the use of the da Vinci Surgical System in various procedures. Within this body of evidence, many benefits of robotic-assisted surgery have been demonstrated compared to open surgery, including less blood loss, fewer complications, shorter hospital stay, smaller incisions for minimal scarring, and faster recovery and return to daily life,” Intuitive said.

In the first six months of this year, Intuitive put aside $16 million to settle legal claims, it reported to regulators.

Problems specific to robot-aided surgery may arise from hardware or software issues and human error, said Scott Lucas who, as director of accident and forensic investigation at the ECRI Institute, studies the da Vinci robots that dominate robot-assisted surgery.

The robots perform a variety of surgeries, including gynecological, cardiac, urologic and colorectal, according to the company.

Hershey, a mother of two adult children who lives near Palm Springs and owns a garage door company with her husband, felt fine after her hysterectomy, spending a night in the hospital and returning home the next day. Severe, stabbing pain started that night, and she was taken by ambulance to the hospital, she said. After more than a week of tests, scans and examinations, Hershey was left with “a lot of pain and no answers.”

Her surgeon advised another surgery to find out what was wrong, and it turned out that what was wrong appeared to be the same thing that many other da Vinci patients cited in claims and lawsuits: She had damage to an internal organ; in her case, a hole in her bowel.

Today, Hershey still can’t lift heavy items or even take out the trash, and she’s had to stop swimming because too much activity causes her stomach to swell and harden, she said.

“I was very active,” she says of her life before surgery. “All that had to stop.”

So far, just two lawsuits against Intuitive over the da Vinci robots have gone to trial. In April 2016, the company settled during the third day of jury deliberations in Santa Clara County Superior Court in a suit launched by Michelle Zarick, of Sacramento, over complications from a hysterectomy. A case in Washington State that hinges on claims that Intuitive failed to properly train a doctor who used a da Vinci robot is ongoing. Hershey’s case is scheduled to go to trial in June.

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Intuitive has reached confidential settlements in “many” complaints against it, the company said in an April regulatory filing. Claims of hardware problems central to many lawsuits revolve around electricity allegedly escaping from instruments and causing burns, unseen by the surgeon because they occurred outside the view of the device’s remote camera. The company in 2013 recalled two instruments that were attached to the robot and operated within the body. Intuitive declined to discuss whether there were any changes to patient outcomes after the recalls.

Settling legal claims, even for tens of millions of dollars, probably wouldn’t threaten the viability of a company with billions in annual revenue, said UC Berkeley Law School professor Stephen Sugarman. Intuitive may have settled cases it believed it could win in court, seeking to avoid negative publicity from a trial, Sugarman said.

“On the other hand, it could be that they know they’re going to lose these cases, and what are they going to gain by trying to win?” Sugarman said.

Investors have been showing increasing confidence in Intuitive — the publicly traded company’s stock price climbed fairly steadily from 2009 to 2012, evened off, and then more than doubled between late 2015 and today.

It remains unclear how robot surgery stacks up to traditional surgery on results for patients, said the ECRI Institute’s Lucas.

“It’s not necessarily obviously better as far as clinical outcomes,” Lucas said. “This may improve over time.”

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The devices are in regular use in the Bay Area. El Camino Hospital has four da Vinci robots at its Mountain View facility and two in Los Gatos. El Camino surgeons perform about 30 da Vinci surgeries per week.

“Because we’re a lot more precise with the movement of the robot, we do think the pain is a little bit less,” said Dr. Dwight Chen, who uses the robots for gynecological cancer surgery. “The patients actually get back on their feet quicker, they’re driving quicker, they’re going back to work quicker. They’re getting back to their quality of life quicker.”

But effective manipulation of the robots requires adequate training and continued use, Chen said. “If you do the surgery only once or twice a year, you’re going to start to lose muscle memory,” Chen said.

Any problems for patients from da Vinci surgery today likely arise from doctors not using the machines properly, Chen believes.

“You get these people who aren’t very good, who aren’t being watched over,” Chen said. “The robot doesn’t make a bad surgeon a good surgeon. The robot actually enhances what you can do. But if you’re a bad surgeon, you’re still going to be a bad surgeon with a robot.”