Sir: Conjoined twinning is a rare congenital malformation. A pair of gastrothoracopagus conjoined twins were admitted to our hospital in April of 2005. They survived and were successfully discharged, and this was the seventh successful case reported in China. Full-term female gastrothoracopagus A and B twins with a common umbilical cord and placenta, born on May 8, 2005, by cesarean section, were admitted 23 days after birth, with a total body weight of 5100 g. The conjoined part ranged from the level approximately 3 cm above the nipple to the umbilicus (Fig. 1). Type B ultrasound, computed tomography, and magnetic resonance imaging showed that the anterior parts of the fourth through tenth ribs were absent, as was most of the superior abdominal wall, so that the pericardial and abdominal cavities were communicating, and the livers were also conjoined. They had independent circulatory, alimentary, and genitourinary systems. There was a bridge between their hearts: dextrocardia with atrial septal defect for twin A and dextroposition superior vena cava for twin B. The skin expanders were embedded 60 days after birth when the patients' general status was fine and the total body weight had reached 6400 g.Fig. 1.: The conjoined part ranged from the level approximately 3 cm above the nipple to the umbilicus.The first-stage operation was performed under venous and local anesthesia; four 150-ml cylindrical expanders were embedded, with the injection pots placed outward. The sutures were removed 1 week later and we began to inject normal saline into the expanders two to three times per week until reaching the nominal volume in the third week. One week later, that is, 90 days after birth, the separation was performed (Fig. 2).Fig. 2.: Photograph obtained postoperatively.The second-stage operation was performed under systemic anesthesia. Two expanders were removed. Then, we entered the thoracic cavity and the pericardium was connected. Their hearts were independent after opening the pericardial cavity, and there was a vessel (approximately 1 cm in diameter) between two ventricles (one for each heart), which was ligated and cut off. Then, we separated the thorax. Afterward, we turned into the abdominal cavity and observed the independent portal systems and alimentary tracts. The anterior margins of their livers were fused. We separated them gradually, and the section was approximately 10 × 13 cm. We sheared the junction of the diaphragm and completely separated the two infants. Allogenic pericardium grafting was used to repair the defect of the pericardium. A monofilament polypropylene patch was used to reconstruct the abdominal wall. A porous high-density polyethylene implant (Medpor; Porex Surgical, Newnan, Ga.) was used to reconstruct the defect of the sternum and ribs. We covered the Medpor supporter with expanded skin flaps, and the thoracic wall was closed, but the closure of the abdominal wall was difficult to manage. Thus, we designed a local rotating skin flap (approximately 12 × 6 cm) in the right hypogastrium to repair the defect, advanced the left inferior expanded flap to the right to cover the donor site, and sutured the wound free of tension. Both of the twins survived, with a body weight of 4500 g and 4700 g, respectively, on discharge. An accurate assessment of conjoined lung, heart, and great vessels is critical for a successful separation. Good nourishment, sufficient preoperative preparation, and excellent physiologic status are critical for a good prognosis. Allogenic pericardium is a preferable repair material for pericardium, as it avoids conglutination. For sternum defects, Medpor has the advantage that it allows blood vessels to grow into it, and the granulation tissue can evolve early. In this patient, we could see that there was well-developed granulation tissue on the surface of the Medpor implant, and the transferred skin flaps healed rapidly, and this material is plastic in warm water. There have been successful cases of repair of the abdominal wall with a terylene patch, and no better material has been available to replace it until now. Use of expanded skin for coverage may be the optimal method at present. Skin expansion is a favorable method with which to repair skin defects, although the application of skin expanders to conjoined twins has rarely been reported. From this case, we realized that skin expansion in infants can be achieved rapidly; however, postoperative care should be intensified, and local compressing should be avoided to reduce postoperative complications. Jiaming Sun, M.D. Yiming Zhang, M.D. Qinglan Ruan, M.D. Shaotao Tang, M.D. Zongquan Sun, M.D. Rui Zeng, M.D. Department of Plastic Surgery Union Hospital Huazhong University of Science and Technology Wuhan, China