The routine surgical procedure Joan Rivers was supposed to undergo turned deadly when a doctor who arrived at the clinic with the legendary comic’s entourage performed an unplanned biopsy on her vocal cords, a medical source who was briefed on the case told The News.
Such a procedure is not supposed to be performed outside of a hospital, according to medical experts.
The Aug. 28 biopsy at Yorkville Endoscopy, an E. 93rd St. clinic that usually only deals with digestive issues, caused Rivers’ vocal chords to seize — a condition doctors call a laryngospasm — cutting off her air supply, the source said.
“A biopsy like that should only be done in a hospital setting,” the source said.
“If she had been in a hospital when it happened, she might have been okay,” the source said.
Rivers’ doctor — who identified himself as an ear, nose and throat specialist — asked if he could use their instruments when the clinic’s doctor noticed “something” on Rivers’ vocal chords, according to the source.
“He asked and they let him,” the source said. “A huge no-no.”
The source added that the “Fashion Police” star had only signed off on an endoscopy — not the far more dangerous biopsy of her vocal chords.
A representative for Rivers declined to comment. A spokeswoman for Yorkville Endoscopy said she couldn’t comment because of patient confidentiality laws.
Last week, a rep for the clinic described the medical facility to ABC News “as a federally and state licensed facility, has the same level of life-saving and resuscitation devices (such as state-of-the-art cardiac defibrillators, airway management equipment, etc.) found in any hospital emergency room or hospital-based operating room.”
The Yorkville spokesperson added, “Yorkville Endoscopy has performed 18,000 procedures since it opened in February 2013. Yorkville Endoscopy has maintained an exceptional safety record that far exceeds the national average.”
The Brooklyn-born comedian was put in a medically induced coma Aug. 28 and died at Mount Sinai Hospital Sept. 4 after she was removed from life-support. An autopsy performed by the medical examiner was inconclusive and more tests were being done to determine the cause of death.
State health officials said last week they are taking a closer look at the Upper East Side clinic.
“The State Health Department is investigating the matter,” agency spokesman James O’Hare said.
There is no criminal investigation of the clinic.
Rivers was undergoing what friends have described as “a diagnostic procedure [to] see why her voice had gotten raspy.”
She was under general anesthesia when something went wrong and 911 was called from Yorkville Endoscopy at approximately 9:39 a.m.
By 9:46 a.m., paramedics and other first responders were on the scene and when Rivers arrived at Mount Sinai Hospital at 10:08 a.m. she was already on life support, according to reports.
Rivers was eulogized Sunday at a star-studded funeral at Temple Emanu-El on the Upper East Side by pals Howard Stern and Deborah Norville.
The service also included a solo from Tony-winning actress Audra McDonald, who sang “Smile,” and Hugh Jackman, who sang “Quiet Please There’a Lady on Stage.”
Outside the synagogue, the streets were lined with throngs of fans and paparazzi — just as she had wished.