Both Bernardo and Arthur Lima are four years old.
Brazilian twins who were conjoined at the head have been successfully separated by a UK-based surgeon, a report in Independent said. Bernardo and Arthur Lima, both almost 4, underwent at least seven surgeries in Rio de Janeiro, with Dr Noor ul Owase Jeelani providing guidance from London's Great Ormond Street Hospital. The last two surgeries lasted 33 hours of operating time to separate the boys with fused brains - called craniopagus twins - and involved more than 100 medical staff, the outlet further said. Surgeons spent months practicing various techniques in virtual reality before the delicate procedure began for real.
Independent said that Dr Gabriel Mufarrej, the head of surgery at Instituto Estadual do Cerebro Paulo Niemeyer, was also supervising the surgery along with Dr Jeelani. The UK-based paediatric surgeon described the operation as a "remarkable achievement, the outlet further said in the report.
Since the twins are almost four years old, they are also the oldest craniopagus twins with a fused brains to have been separated, said Independent.
UK-based Metro quoted Dr Mufarrej as saying that the parents of the boys came to the Brazilian hospital two-and-a-half-years-ago. "They had become part of our family in the hospital," he added.
Gemini Untwined, a charity founded by Mr Jeelani, helped the boys' parents raise funds for the surgery. The charity said separating Bernardo and Arthur was one of the most complex separation processes ever completed, adding that many surgeons did not even think it possible.
Both the boys are recovering well in hospital, and will be supported with six months of rehabilitation, Metro further said in its report quoting the charity.
According to Gemini figures, one in 60,000 births results in conjoined twins, and only 5 per cent of these are craniopagus children.