A pair of rare conjoined twins from Odisha have safely come out of the effect of anaesthesia after their 16-hour separation surgery at the All India Institute of Medical Science (AIIMS) but neurosurgeons say the real challenge will be for their brains to function independently of one another.Jagannath Kanhar and Balram Kanhar were joined at the head at a 180-degree angle and a team of 40 doctors operated on the 27-month-old babies on Thursday to separate them. It was India’s first separation surgery of craniopagus twins, who also shared brain tissue, nerves and major blood vessels.“Both the babies are stable and safely out of anaesthesia. There has been no deterioration in their condition. However, we have to look out for progress,” said Dr Girija Rath, professor of neuroanaesthesia at AIIMS.Called Jagga and Balia by their family, the twins were referred to AIIMS from the Cuttack District Hospital in Odisha, where they were born.Recovery for neurosurgery takes several weeks to months but the real challenge for the twins is whether they can learn to live without each other.“In major neurosurgeries like this one, the physiology of the brain changes drastically. The brains of the twins were dependent on each other and now that they have been separated, they would have to learn to live with it,” said Dr Rath.The doctors will be able to tell whether the babies face any neurological deficits once they are fully awake.“The next 18 days would be critical,” said Dr SS Kale, professor of neurosurgery at AIIMS.Thursday’s surgery, in which the brain has been separated and their skulls covered with skin flaps, is the second procedure the Kanhar twins have undergone. On August 28, a vein graft was inserted into their brain.Doctors have said a third surgery to graft their skull bones and cover the exposed brain will be attempted in a couple of years.Fifty-nine such craniopagus surgeries have been performed worldwide.Separation surgeries for two other sets of craniopagus twins – Vani and Veena from Hyderabad and Saba and Farah from Patna – were planned in India in the past, but abandoned because the risks were too high.