A new breed of cosmetic surgery chains, some backed by private equity investors, are competing for a slice of the nation’s growing body-contouring market.

The chains sell an array of body-reshaping operations, such as “Mommy Makeovers” and liposuction, targeting customers willing to pay up to $20,000 out-of-pocket for a new figure.

A joint investigation by KFF Health News and NBC News found that cosmetic surgery chains have been the target of scores of medical malpractice and negligence lawsuits alleging disfiguring injuries — including 12 wrongful death cases filed over the past seven years.

Injured patients have accused the chains of hiring doctors with minimal cosmetic surgery training, of failing to recognize and treat life-threatening infections and other dangerous surgical complications, and of using high-pressure sales tactics that minimized safety risks, court records show. The companies have denied the allegations in court.

“These people promise to turn you into the fairest person in the land, and the risks aren’t often worth the reality,” said Sean Domnick, a Florida attorney who heads the American Association for Justice, a trial lawyers’ group.

Robert Centeno, a medical director for Sono Bello, the largest of the chains, disagrees. He said the company’s mission is to “help each and every one of our patients live their best lives now.” Sono Bello offers “life-changing transformations” that enhance a person’s “appearance as well as their quality of life,” said Centeno, a surgeon at the company’s Troy, Michigan, office. Sono Bello boasts it is “America’s top cosmetic surgery specialist.”

But many established plastic surgeons worry that chain surgery groups may be inclined to spend more effort on marketing and sales than on making sure their doctors are properly credentialed and capable of handling any complications that arise.

Medical practices owned by private equity or investment firms have more money to spend drawing in patients and “the ability to operate and provide quality patient care is now less important,” said Mark Domanski, a plastic surgeon in Northern Virginia.

Erin Schaeffer, 37, spent a week in a Florida hospital battling a severe infection after having a type of tummy tuck and liposuction at the Jacksonville branch of Sono Bello.

More than a year later, scars remain on her lower body. And in a lawsuit, she is accusing Sono Bello of using an obstetrician-gynecologist who was inadequately trained to remove her excess skin and fat, a procedure she says caused excruciating pain. Sono Bello and the doctor denied the allegations in a joint court filing.

“I literally felt like I was skinned alive,” Schaeffer said.