Anatomy of successfully separated thoracopagus-omphalopagus conjoined twins.

The birth of conjoined twins occurs in approximately 1 in 50,000 to 1 in 100,000 deliveries, and the majority are either stillborn or die early in life. Approximately 184 successful separations have been described. The authors describe the preoperative radiologic evaluation of a set of thoracopagus-omphalopagus twins and their successful surgical separation. Preoperative radiologic imaging demonstrated that the twins did not share myocardium, but an ectopic cordis was present. The inferior vena cavae entered the right atria at more acute angles than normal. The liver was fused, two gallbladders were present, and there was a large bridging portal vein that crossed the hepatic isthmus of one twin to the conjoined twin's portal venous system. Replaced hepatic arteries originated from the superior mesenteric arteries. Each twin had separate kidneys, colons, and rectums. Preoperative tissue expansion was necessary, and the twins were separated at 5 1/2 months of life. Successful separation of twins conjoined by several organ systems requires a multispecialty approach. Preoperative knowledge of shared anatomy is necessary for adequate preparation and planning. Despite meticulous preoperative investigations, certain anatomy can only be discovered at the time of surgery, and the ability to adjust to these findings is imperative.