Dr Maurice Jerome Day, who practices as Dr Jerry Day, came under scrutiny from June 19, 2018, when one of his patients died on the operating table at Wollongong Private Hospital.

The hospital announced it was reviewing six of his surgical cases from the past two years.

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These included a complaint that he placed discs in the wrong position on a patient's spine in 2005, then cut two veins in a second procedure, causing the woman to go into a coma for two days.

A January 2009 complaint alleged a patient became a paraplegic after complications from another operation.

In 2017 Dr Day was sued over a claim he was inadequately qualified to perform surgery to remove a brain tumour, with the patient left with "catastrophic brain injury" afterwards.

Another incident, in which a patient complained of significantly worse leg pain and loss of sensation after a botched fusion and disc replacement, resulted in a complaint to the Health Care Complaints Commission on August 9, 2019. A scan revealed a fragment of bone had protruded into the disc area, causing nerve compression. The patient suffered greater pain, weakness and sensory loss after Dr Day performed a second operation to remove the bone.

With its review pending, the private hospital placed a condition on Dr Day's accreditation, requiring another neurosurgeon to be present whenever he performed instrumented spinal procedures - those procedures where screws and rods are inserted in addition to bone graft.

The hospital later added other conditions, requiring Dr Day to perform 10 instrumented spinal procedures in the presence of a supervising neurosurgeon who was then to provide a report that may result in the conditions being lifted.

Dr Day completed the 10th of these procedures, but then began operating without supervision, in breach of the hospital's conditions. An August 27, 2019 procedure went ahead without the required supervisor and - also in breach of the conditions - involved the use of a Mazor robot, which "had not been used by any of the neurosurgeons operating in the hospital since the death of a ... patient in June 2018".

In a court statement, Dr Day said his accreditation at the private hospital was confirmed in September 2019, without mention of any conditions, so he believed they no longer applied.

The private hospital terminated his accreditation on October 4, 2019 and his status as a visiting medical officer at Wollongong Hospital was suspended soon afterwards.

The medical council imposed three conditions on his registration after a December 6, 2019 hearing, including a blanket ban on instrumented spinal surgery and a condition that he have a supervisor attend his other operations and confirm "that the correct level [of the spine to be operated on] has been identified and this corresponds to the levels consented to by the patient".

The council found the doctor's practice "posed a risk to the public", warranting urgent action. It noted the doctor had "a higher number of serious post-operative outcomes than would be expected from his practice", including "multiple examples of instrumented spinal surgery where there has reportedly been possible misplacement of instrumentation, resulting in significant neurological complications".

The doctor challenged the council's decision in the Civil and Administrative Tribunal, which heard he performed about 150 operations a year and that about a third of his work was instrumented spinal surgery.

Dr Day told the tribunal he had been personally and professionally devastated by the proceedings, and called for an easing of restrictions on his registration, noting his work had withstood scrutiny from three neurosurgeons.

"Like any neurosurgeon performing complex procedures I have had my share of adverse outcomes, but none of those neurosurgeons consider that I have practised at a level below the standard expected," he said.

He said the requirement to have a supervisor in theatre with him made it very difficult to operate at all, as there was only one neurosurgeon he could call on and that person was deemed unsuitable as they had previously had conditions imposed on their registration by the medical council.

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The tribunal considered supportive references from colleagues including Dr Raj Reddy, who wrote, "I would have no concerns if Dr Day was looking after myself, any member of my family or my friends".

A professor reporting to the private hospital supported an easing of conditions for certain, mostly straightforward procedures. He told the tribunal the conditions - particularly that requiring the presence of a council-approved supervisor - were "restrictive to the point that they will all but prevent Dr Day performing any spinal surgery at all".

Orders handed down by the tribunal on Wednesday reinstated Dr Day's right to perform some instrumented spine surgery under strict conditions, including that the surgery be approved by a neurosurgeon who must stay and supervise the procedure.

The doctor can perform non-instrumented surgery, but only with a council-approved neurosurgeon or orthopaedic spinal surgeon attending mid-operation, to confirm that the correct level has been identified and that this matches the levels consented to by the patient.

Dr Day must also have review meetings with a supervisor fortnightly and was ordered to pay 75 per cent of the medical council's court costs.

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