A Dallas surgery center is being sued by a workers' compensation firm that says it’s on the hook for over $1 million to maintain care for a patient whose ankle surgery resulted in a brain injury.

The Texas Institute for Surgery at Texas Health Presbyterian Dallas performed what should have been a routine orthopedic procedure on a woman who slipped and fell at work in early 2016, the lawsuit says.

Surgery to repair the woman's right ankle was paid for by Zenith Insurance Co. That California-based group provided workers' compensation coverage to the woman's employer, a subsidiary of Dunkin' Donuts.

But the woman, identified as Dallas County resident Tyra Price, suffered preventable complications during the two-hour outpatient surgery in May 2016, the insurance company says in its complaint, filed Jan. 24 in the U.S. District Court for the Northern District of Texas.

Zenith said it doesn't comment on pending litigation.

Neither the Texas Institute for Surgery nor anesthesiologist John Vincent Zipper, both named as defendants in the case, could be reached for comment.

The lawsuit contends that after Price received anesthesia, vomit blocked her airway and the lack of oxygen resulted in the brain injury.

Zenith says Price was morbidly obese, which can increase the risk for certain side effects and complications. It also contends that members of the surgical team did not fully assess her risk, and were not ready to respond to "reasonably foreseeable" complications.

Zenith said in court documents that it has paid, and continues to pay, millions of dollars in medical and other expenses.

“And the amount of plaintiff’s damages is expected to increase substantially,” the company said. It’s seeking compensation from the defendants.

The family couldn't be reached for comment.

In a court petition filed in September 2016 in Dallas County, Price's daughter sought primary guardianship. That filing described Price as suffering from "significant cognitive limitations" that included short- and long-term memory loss, deficits in reasoning abilities and an inability to feed or clothe herself.

Price was to continue receiving workers' compensation income "with an approximate value of $8,000 per year for as long as she is considered fully disabled," the filing said.

In a plea two years ago on the crowdfunding website GoFundMe, Price's daughter described the ordeal as the family's "worst nightmare." A later post said Price had been transferred to Houston for rehabilitation.

"Forced to start completely over," the post said, "we are taking everything step by step, & day by day."

Read the lawsuit here:

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