"He also said that in hindsight this was naive and foolhardy - a misjudged attempt to relieve the tension in theatre", Badenoch reportedly said in court. The machine acts as coagulator that seals bleeding blood vessels with an electric beam.
Farrer fined Bramhall £10,000 ($13,650, €11,250) and sentenced him to 12 months of unpaid community work.
The 53-year-old surgeon resigned from Queen Elizabeth Hospital in Birmingham, England, in 2014 after another doctor discovered what he'd done.
Simon Bramhall, who was supported in court by former patients, said his actions were an attempt to relieve tension during surgery.
Simon Bramhall, 53, told police he used an argon beam machine to initial the organs to relieve operating theatre tensions following hard and long transplant operations in 2013.
He previously pleaded guilty to two counts of assault by beating relating to two incidents on February 9 and August 21 in 2013, and denied the more serious charges of assault occasioning actual bodily harm.
He even boasted to a nurse who witnessed one of the assaults at Birmingham's Queen Elizabeth Hospital: "This is what I do".More news: Mondelez International, Inc. (MDLZ), KeyCorp. (KEY) — Trending Stocks Alert
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Opening the facts of the case against Bramhall, Tony Badenoch QC, prosecuting, said one of the surgeon's victims had been left feeling "violated" and suffering psychological harm. A prosecutor criticized the surgeon, saying his actions were "without legal precedent in criminal law". This was conduct born of professional arrogance of such magnitude that it strayed into criminal behaviour. I accept that on both occasions you were exhausted and stressed and I accept that this may have affected your judgment.
"And no greater vulnerability than that of a patient who's under general anaesthetic and the breach of that trust and the abuse of that power were aggravating features that led us to conclude it was the right thing to do to take this case forward".
One of the 4cm-high sets of initials was found by another surgeon after a victim, referred to in court as Patient A, returned for further treatment around a week after undergoing a transplant.
Frank Ferguson, head of special crime at the CPS, said Bramhall was a highly-respected surgeon to whom many patients owed their lives.
It will be up to the General Medical Council to decide whether Bramhall will be struck off or allowed to continue doing the job he loves.
The University Hospitals Birmingham NHS Foundation Trust said: "The Trust is clear that Mr Bramhall made a mistake in the context of a complex clinical situation and this has been dealt with via the appropriate authorities, including the Trust as his then employer".