Doctors in Texas will attempt to separate two 10-month-old sisters born conjoined below the waist.
The multi-hour operation is set for Tuesday at Driscoll Children's Hospital in Corpus Christi.
The girls - Ximena and Scarlett Hernandez-Torres - share a colon and bladders that will be reconstructed. Their identical triplet sister, Catalina, was born without serious health issues.
The staff at Driscoll Children's Hospital has cared for the girls since they were transferred to the facility hours after birth at another area hospital.
Dr. Haroon Patel says a team of specialists has been working for months to prepare for the surgery, which could last 12 to 18 hours.
A hospital statement says doctors have a positive outlook for the children's recovery. The girls will require additional surgeries as they grow.