A neurosurgeon from England has successfully separated two Brazilian twins who were conjoined at the head.
On Monday, the charity Gemini Untwined announced that Bernardo and Arthur Lima, 3, who were born with "fused brains," had made it through seven procedures at the Instituto Estadual do Cerebro Paulo Niemeyer in Rio de Janeiro under the direction of pediatric surgeon Noor ul Owase Jeelani from London's Great Ormond Street Hospital, reported The Independent.
The young twins were treated for a total of 33 hours during the final two surgeries alone and were attended by almost 100 medical staff, The Evening Standard added Monday.
The procedures, which Jeelani called a "remarkable achievement," required medical professionals to master virtual reality training programs for months before they actually attempted the surgeries in real life.
Thanks to this training surgeons in separate countries worked together in the same "virtual reality room" for the first time in history, Jeelani added, according to The Evening Standard.
Jeelani, who founded Gemini Untwined in 2018, said he was "really apprehensive" about the procedure since past unsuccessful attempts to separate the twins had created complications due to scar tissue, reported The Evening Standard.
Despite this, he praised the operations' success and told The Evening Standard that "in some ways these operations are considered the hardest of our time."
"The successful separation of Bernardo and Arthur is a remarkable achievement by the team in Rio and a fantastic example of why the work of Gemini Untwined is so valuable," Jeelani added in a statement obtained by The Independent.
"Not only have we provided a new future for the boys and their family, we have equipped the local team with the capabilities and confidence to undertake such complex work successfully again in the future," Jeelani's statement continued. "It is through this process of teamwork and knowledge-sharing globally that we can hope to improve the outcome for all children and families that find themselves in this difficult position."
"This is only possible through generous donations from members of the public," Jeelani finished.
During the final, 27-hour operation, Jeelani took only four 15-minute-long breaks for food and water, according to The Evening Standard.
"There were a lot of tears and hugs," Jeelani told the paper. "It was wonderful to be able to help them on this journey."
Never miss a story — sign up for PEOPLE's free daily newsletter to stay up-to-date on the best of what PEOPLE has to offer, from juicy celebrity news to compelling human interest stories.
Gemini Untwined's website identifies the condition the Lima twins were born with as craniopagus twins, "a term for two independent children that are connected to each other with fused skulls, intertwined brains, and shared blood vessels."
The charity's website notes that one in 60,000 births result in a pair of conjoined twins, and five percent of those births are craniopagus twins.
"Our mission is to offer hope and medical solutions to challenges faced by craniopagus children and others with complex craniofacial conditions," reads Gemini Untwined's website. "To further global health equity and access, enabling the treatment of children and the training of medical teams across the world; and to continue to push the boundaries of medical innovation and research."
The twins will go through six months of rehabilitation following the surgeries and are recovering in the hospital, the charity told The Independent. The boys are now the oldest set of craniopagus twins with a fused brain to be separated, the newspaper added.
On Monday, Gemini Untwined CEO Marelisa Vega told PEOPLE in a statement that the charity is "incredibly proud of the Gemini Untwined team, especially our founder Mr. Owase Jeelani and Professor David Dunaway, who have been advising the team at the Instituto Estadual do Cérebro Paulo Niemeyer for months via virtual reality," before Jeelani flew to Rio de Janeiro to perform the final surgeries.
In the three years since Gemini Untwined's founding, the organization told PEOPLE that it has performed six surgeries separating craniopagus twins, which it said "is more than any one organization." All twelve children involved in the surgeries have survived, it said.
Jeelani directed previous operations on twins from Pakistan, Sudan, Turkey and Israel, according to The Evening Standard.