 In 1987, Carson was the lead neurosurgeon of a 70-member surgical team that separated conjoined twins, Patrick and Benjamin Binder, who had been joined at the back of the head (craniopagus twins); the separation surgery held promise in part because the twin boys had separate brains.The Johns Hopkins surgical team rehearsed the surgery for weeks, practicing on two dolls secured together by Velcro.Although follow-up stories were few following the Binder twins' return to Germany seven months after the operation, both twins were reportedly "far from normal" two years after the procedure, with one in a vegetative state.