Surgery to separate 1-year-old German twins joined at the tops of their heads was interrupted late Saturday after one of the girls suffered unstable vital signs, doctors said. The procedure for Lea and Tabea Block was halted after "metabolic complications" caused the problem in one of the twins, according to a statement issued by Johns Hopkins Children's Center in Baltimore, Maryland, about 80 kilometers from Washington. The girls were in stable condition after the operation was "temporarily halted". The hospital in Baltimore, about 80 kilometers from Washington, said that doctors had not yet decided whether or when the surgery might resume. The halt came about 12 hours into a procedure in which surgeons had expected to work for 24 to 48 hours. An earlier hospital statement had described Lea and Tabea as doing well, less than three hours before the interruption was announced. The girls share blood vessels in their brains. Neurosurgeons had already opened the dura, the fibrous covering of the brain, and work was underway to separate major blood vessels. A team of 50 doctors and nurses was working in shifts to separate the girls, who are from the town of Lemgo in the German state of Westphalia. The lead surgeon, Dr. Benjamin Carson, director of paediatric neurosurgery at Johns Hopkins, has performed four similar separation procedures - twice successfully. Of the 60 children who have undergone similar procedures worldwide, half have lived, though 17 of the 30 survivors have disabilities, the German news magazine Stern reported. The Block sisters, who were born on August 9, 2003, underwent a preparatory procedure in June, in which tissue expanders were inserted to stretch their scalps to give doctors enough skin to cover their skulls at the end of the separation surgery.
