Star brain surgeon Charlie Teo has been accused of lying to a medical disciplinary hearing board over two surgeries he conducted that left patients with catastrophic brain injuries.
Lawyers for the state health watchdog grilled Dr Teo on Monday over what he knew to be the risks involved with one surgery in 2018, and how that risk was conveyed to the patient.
During the hearing, it was put to Dr Teo he has changed his evidence over where he believed the tumour was in the brain, and the decision to operate, in order to reduce his liability.
Under questioning Dr Teo firmly denied he had deliberately altered his evidence in order to mislead the committee.
The high-profile surgeon was greeted by a large crowd of supporters when he arrived for a fifth, and possibly final day, of a Health Care Complaints Commission (HCCC) hearing in Sydney.
Lawyer for the HCCC, Kate Richardson SC put it to Dr Teo he changed his evidence to protect himself after going ahead with the high-risk surgery.
"I want to suggest to you that you deliberately gave untruthful evidence to the committee for that reason. Do you accept that?" she asked.
"No," Dr Teo replied.
Last week, the committee was told Dr Teo differs with two expert witnesses, Bryant Stokes and Andrew Morokoff, who said the risk of "profound neurological deficit" from conducting the surgery was 60 per cent.
Due to his different interpretation of brainscans, Dr Teo told the patient the risk of death, paralysis or locked in syndrome was just five per cent.
Ms Richardson pressed Dr Teo why he wasn't clearer with the patient about whether the tumour was in the tectal plate region of the brain, rather than the tegmental, which is more dangerous to operate on.
He said he didn't want to confuse patients by getting into the "finer neurosurgical details".
"These people are emotionally charged. They've heard a lot of information. You don't want to confuse them," he said.
"I'm not going to go into the finer surgical aspects with a patient. I think that's inappropriate."
In August 2021, the NSW Medical Council restrained Dr Teo from operating without the approval of another doctor after an investigation by the HCCC.
He has repeatedly denied any wrongdoing.