Consultant surgeon Simon Bramhall is charged with burning 'SB' onto the livers of two patients during transplants when he worked at Queen Elizabeth Hospital in Birmingham, West Midlands.
During one operation on 9 February 2013, the 53-year-old experienced surgeon allegedly assaulted a male patient causing actual bodily harm. Four months later on 21 August 2013, a female patient had a transplant and Dr Bramhall is alleged to have caused her actual bodily harm.
Liver surgeons use an argon beam to stop livers bleeding, but can also use it to burn the surface of the liver to sketch out the area of an operation.
It is usually not harmful and the marks would normally disappear but one of the patient's liver did not heal itself in the expected manner and the initials were found in a follow-up operation.
Dr Bramhall of Redditch, Worcestershire, who has been a liver, spleen and pancreatic surgeon for 12 years, denies two counts of actual bodily harm.
The next hearing is at Birmingham Crown Court next month.