Patrick and Benjamin Binder were conjoined twins, joined at the head, born in Germany in February 1987, and separated at Johns Hopkins Children's Center on 6 September 1987. They were the first twins to be successfully separated by Ben Carson, a neurosurgeon assisted by Donlin M. Long of Baltimore, Maryland. For this operation, the surgeons could prepare by studying a three-dimensional physical model of the twins' anatomy. Carson described this separation as the first of its kind, with 23 similar attempted separations ending in the death of one or both twins.
Although the surgeons were able to separate the boys, both were left profoundly disabled.