Lawyers for brain surgeon Charlie Teo have warned a disciplinary board to avoid “hindsight bias” in ruling over surgeries he performed that left two female patients with catastrophic brain injuries.

Dr Teo faced a final Health Care Complaints Commission (HCCC) hearing in Sydney on Wednesday, before deliberations begin as to whether he should receive a professional reprimand and additional oversight on his practice.

Allegations include that Dr Teo failed to properly inform the patients of the risks involved with surgery, failed to gain proper patient consent, slapped one of the patients in the face and used unprofessional language during consultations.

Commission counsel Kate Richardson said during her closing submission that Dr Teo removed an extensive section of one patient’s right frontal lobe without informing her first.

Dr Teo’s lawyer Matthew Hutchings argued what neurosurgeons intend to do prior to a surgery, and what actually occurred, sometimes varied greatly.

He said judgments were sometimes made “in the heat of the moment” during a procedure and that a “hindsight bias” shouldn’t be applied to the complaints.

Speaking to media after the hearing, Dr Teo described Australia’s medical complaints system as “guilty until proven otherwise”.

“It’s been very depressing sitting in there listening to people making judgment about you. About things that you know are completely incorrect,” Dr Teo said.

“How you’re not empathetic, how you treat your patients with disrespect. I mean, that’s just not me.”

Earlier on Wednesday, Ms Richardson argued Dr Teo showed a lack of judgment and insight in how he interacted with patients’ families and how he dealt with discrepancies between his own views and the opinions of other experts.

She questioned the future risk to the public in Dr Teo’s response to allegations he slapped a patient across the face in view of her family members.

Dr Teo told the hearing this week it was not a “Will Smith-type slap” and that he would continue to rouse patients using the method, despite three other experts telling the hearing slapping a patient is completely unacceptable.

“He identified in his view his key shortcoming was that he did it and the family could see,” Ms Richardson said.

Mr Hutchings noted Dr Teo’s skill as a surgeon was not in question by any of the experts who appeared at the hearing.

“It cannot be said the surgery wasn’t done with due care and skill, appropriately attempting to deliver on what was planned,” he said.

Passionate public and professional support for Dr Teo may hold little weight in the board’s decision, including claims that imposing additional restrictions would be against the interest of current and future patients.

Letters from 10 overseas-based neurosurgeons and 47 former patients and their families were tendered to the board, along with three emails and one letter of support from Australian medical professionals.

“There is not anything in those letters or statements on their face to show the authors … were aware of the complaints and their particulars,” commission junior counsel Megan Caristo said.

No formal statements of support were provided by Australian-based neurosurgeons, despite Dr Teo reaching out to two of his colleagues, the hearing was told.

“I think they don’t want to be seen as a Charlie Teo advocate because it has polarised the neurosurgical community,” Dr Teo said.

Former Australian cricket captain Steve Waugh attended Wednesday’s hearing, describing Dr Teo as a “good guy and a great Australian”.

A four-person Professional Standards Committee will deliberate on a decision.

-AAP