An autopsy was not carried out on Joan Rivers' body.

According to state law, doctors will honour the requests if there is no evidence of criminality associated with the death.

While it was determined Joan had suffered a "predictable" complication from the procedure itself, the decision not to carry out a post-mortem examination meant it was impossible to establish if there had been trauma such as a puncture in the throat.

The New York City Medical Examiner's Office released a statement last week stating that Joan's brain had been starved of oxygen after she suffered cardiac and respiratory arrest on the operating table.

The report reads: "OCME has completed its investigation. The cause of Ms Rivers' death is anoxic encephalopathy due to hypoxic arrest during laryngoscopy and upper gastrointestinal endoscopy with propofol sedation for evaluation of voice changes and gastroesophageal reflux disease.

"The manner of death is therapeutic complication. The classification of a death as a therapeutic complication means that the death resulted from a predictable complication of medical therapy."

The showbiz veteran had been undergoing the throat operation at the private Yorkville Endoscopy in New York City, but was rushed to Mount Sinai hospital and placed in a medically-induced coma after doctors failed to resuscitate her at the clinic.