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Cardiac relocation and chest wall reconstruction after separation of thoracopagus conjoined twins with a single heart
Cardiac Relocation and Chest Wall Reconstruction After Separation of Thoracopagus Conjoined Twins With a Single Heart By Steven J. Fishman, Mark Puder, Tal Geva, Kathy Jenkins, Moritz M. Ziegler, and Robert C. Shamberger Boston, Massachusetts
Separation of thoracopagus conjoined twins with a single heart and the twin reversed arterial perfusion sequence yielded a single surviving infant with a protuberant heart covered by ribs and soft tissue from the nonsurviving twin. At 13 months of age, the heart was relocated in the chest after caudal mobilization of the diaphragms. The protective tissue cage was removed and a normal chest contour estab-
lished. This technique also may be useful in the treatment of thoracic ectopia cordis. J Pediatr Surg 37:515-517. Copyright © 2002 by W.B. Saunders Company.
S
The cardiac apex was elevated by a portion of liver within the protuberant body wall cage. The vena cavae were not angulated significantly at the right atrial junction. At 13 months of age, operative exploration was performed by midline incision and splitting the clamshell-like protuberance of ribs in the midline (Fig 3A and B). Both hemidiaphragms were detached peripherally, tightened, and reattached to the abdominal wall more inferiorly to maintain the liver in a more caudad position. This created more space in the mediastinum. The apex of the pericardium was reoriented leftward and inferiorly such that the entire heart was positioned below the level of the nonprotuberant lateral portions of the anterior chest wall. The heart was held in this new position for 30 minutes, during which there were no significant hemodynamic changes. The ribs of the entire right half and the lower portion of the left half of the protuberant cage were removed. The upper left conjoined ribs were cracked at their union with the patient’s ribs and shaped to bridge the open anterior chest defect over the heart (Fig 3C). Soft tissue closure was achieved with pectoral advancement flaps. A normal torso contour was established with a completely internalized heart (Fig 4). There were no postoperative complications. The child is thriving with normal function and appearance at 22 months of age.
URVIVAL AFTER SEPARATION of thoracopagus conjoined twins with cardiac anomalies is rare. We reported a single survivor after neonatal separation of twins with a single heart and the twin reversed arterial perfusion (TRAP) sequence.1 The ectopic heart was covered with autologous tissue from the nonsurviving twin. The resulting protuberance presented a reconstructive challenge. The Committee on Clinical Investigation, Children’s Hospital, Boston, approved reporting of this experience without review. CASE REPORT Antenatal ultrasound imaging showed a 29-year-old woman to be carrying thoracopagus twins. Echocardiography showed a structurally normal single heart oriented in a mesocardia position with normal great vessels to only one fetus. The apex of the heart protruded into the other twin, but there were no direct vascular connections to this fetus, which had only a rudimentary single, thin-walled, slowly contracting cardiac structure. In a unique conjoined presentation of the TRAP sequence, the acardiac fetus received arterial perfusion from the pump twin through the single umbilical cord. Blood was pumped from the single heart to the placenta by way of one set of umbilical arteries and returned up the other to perfuse the acardiac twin. Retrograde flow in the aorta of the acardiac twin was seen. Nearly immediate neonatal demise was predicted, because the arterial perfusion to the acardiac twin would be interrupted at the moment of umbilical cord ligation. This information facilitated planning of immediate separation after cesarean section delivery with survival of the 1 twin who was potentially independently viable, but doomed to perish along with her sister if unseparated. Because the functionally acardiac twin could not survive, the incision for separation was performed far toward her side of the fusion plane. After division of the fused liver, the flaps of anterior thoracoabdominal tissues from the sacrificed twin were rotated anteriorly to close the ventral tissue deficit of the survivor. The undisturbed protuberant heart was protected by and covered with a cagelike structure created from the autologous ribs and soft tissues of the opposite twin (Fig 1).1 After the infant made a complete recovery and was developing normally, we sought to determine whether the chest wall protuberance could be eliminated. Multiplanar electrocardiogram-gated magnetic resonance images were obtained to assess the spatial relationships between the heart and surrounding organs and inflow vessels (Fig 2). Journal of Pediatric Surgery, Vol 37, No 3 (March), 2002: pp 515-517
INDEX WORDS: Conjoined twins, thoracopagus, chest wall reconstruction, ectopia cordis.
DISCUSSION
Thoracopagus conjoined twins with shared cardiac structures never have been separated to successfully yield 2 long-term surviving children.2 Only 1 long-term survivor has been reported previously after separation of hearts joined at the atrial level.3 Although our twins had a single heart anatomically located between the 2, it had 4 normal chambers and great vessel connections to only 1 twin. Normal cardiac physiology after separation alFrom the Departments of Surgery and Cardiology, Children’s Hospital and Harvard Medical School, Boston, MA. Presented at the 32nd Annual Meeting of the American Pediatric Surgical Association, Naples, Florida, May 20-23, 2001. Address reprint requests to Steven J. Fishman, MD, 300 Longwood Ave, Boston, MA 02115. Copyright © 2002 by W.B. Saunders Company 0022-3468/02/3703-0044$35.00/0 doi:10.1053/jpsu.2002.30867 515
516
FISHMAN ET AL
thoracic ectopia cordis. Autologous tissue coverage by most means typically produces excessive compression of the heart, limiting cardiac output, either by impeding cardiac filling or kinking great vessels.5 There have been few reported survivors of thoracic ectopia cordis.6-8 The intrathoracic cavity has been shown to be diminished in size in these patients.9 Closure in a single stage was
Fig 1. (A) Thoracopagus twins at birth. (B) Appearance of child after separation and coverage of heart with ribs and soft tissues of conjoined twin.
lowed for survival of 1 child. However, the cardiac location presented anatomic challenges similar to those seen in thoracic ectopia cordis: the need for tissue coverage and the protuberant heart. Coverage of body wall defects after separation of conjoined twins with 2 separate hearts has been addressed by the use of prosthetic materials and preoperative tissue expansion.4 Because only 1 surviving child was possible in our case, there was adequate autologous tissue from the other twin to close the defect. Conjoined twins with separate hearts do not have significant malpositioning of the heart. However, protrusion of the heart is the predominant difficulty in
Fig 2. ance.
MRI shows orientation of heart in chest wall protuber-
CONJOINED TWINS
517
Fig 4. Appearance after cardiac relocation and chest wall reconstruction.
thoracopagus conjoined twins with a single heart should include careful observation for reversed flow in the aorta of one twin, suggesting the TRAP sequence. Up to 40% of conjoined twins are stillborn and another 30% survive less than 1 day.10 Twins with an unrecognized TRAP sequence would face certain early demise without immediate separation. If loss of one twin is certain, proper incision placement for separation allows for coverage with autologous tissue. It may be possible to increase the space in the chest by lowering the diaphragms, thus, allowing the protuberant heart to be relocated in the case of either a separated conjoined twin or an infant with ectopia cordis. REFERENCES
Fig 3. (A) Clam-shell appearance of protective cage of ribs from twin covering heart. (B) Split cage over heart relocated into chest. (C) Reconstructed anterior chest wall using upper left conjoined ribs.
achieved by Amato et al8 in part by mobilization of the diaphragms inferiorly. Our case shows several points. In utero evaluation of
1. Norwitz ER, Hoyte LPJ, Jenkins KJ, et al: Separation of conjoined twins with the twin reversed-arterial-perfusion sequence after prenatal planning with three-dimensional modeling. N Eng J Med 343:399-402, 2000 2. Chiu CT, Hou SH, Lai HS, et al: Separation of thoracopagus conjoined twins. A case report. J Cardiovas Surg 35:459-62, 1994 3. Synhorst D, Matlak M, Roan Y, et al: Separation of conjoined twins joined at the right atria. Am J Cardiol 43:662-665, 1979 4. Zubowicz VN, Ricketts R: Use of skin expansion in separation of conjoined twins. Ann Plast Surg 20:272-276, 1988 5. Shamberger RC, Welch KJ: Sternal defects. Pediatr Surg Int 5:156-164, 1990 6. Saxena NC: Ectopia cordis child surviving: Prosthesis fails. Pediatric News 10:3, 1976 7. Dobell ARC, Williams HB, Long RW: Staged repair of ectopia cordis. J Pediatr Surg 17:353-358, 1982 8. Amato JT, Cotroneo JV, Gladiere R: Repair of complete ectopia cordis (video presentation) presented at the American College of Surgeons Clinical Congress. Chicago, IL, 1988 9. Haynor DR, Shuman WP, Brewer DK, et al: Imaging of fetal ectopia cordis: Roles of sonography and computed tomography. J Ultrasound Med 3:25-7, 1984 10. Edmonds LD, Layde PM: Conjoined twins in the United States, 1970-1977. Teratology 24:301-308, 1982
Separation of thoracopagus conjoined twins with a single heart and the twin reversed arterial perfusion sequence yielded a single surviving infant with a protuberant heart covered by ribs and soft tissue from the nonsurviving twin. At 13 months of age, the heart was relocated in the chest after caudal mobilization of the diaphragms. The protective tissue cage was removed and a normal chest contour estab-
lished. This technique also may be useful in the treatment of thoracic ectopia cordis. J Pediatr Surg 37:515-517. Copyright © 2002 by W.B. Saunders Company.
S
The cardiac apex was elevated by a portion of liver within the protuberant body wall cage. The vena cavae were not angulated significantly at the right atrial junction. At 13 months of age, operative exploration was performed by midline incision and splitting the clamshell-like protuberance of ribs in the midline (Fig 3A and B). Both hemidiaphragms were detached peripherally, tightened, and reattached to the abdominal wall more inferiorly to maintain the liver in a more caudad position. This created more space in the mediastinum. The apex of the pericardium was reoriented leftward and inferiorly such that the entire heart was positioned below the level of the nonprotuberant lateral portions of the anterior chest wall. The heart was held in this new position for 30 minutes, during which there were no significant hemodynamic changes. The ribs of the entire right half and the lower portion of the left half of the protuberant cage were removed. The upper left conjoined ribs were cracked at their union with the patient’s ribs and shaped to bridge the open anterior chest defect over the heart (Fig 3C). Soft tissue closure was achieved with pectoral advancement flaps. A normal torso contour was established with a completely internalized heart (Fig 4). There were no postoperative complications. The child is thriving with normal function and appearance at 22 months of age.
URVIVAL AFTER SEPARATION of thoracopagus conjoined twins with cardiac anomalies is rare. We reported a single survivor after neonatal separation of twins with a single heart and the twin reversed arterial perfusion (TRAP) sequence.1 The ectopic heart was covered with autologous tissue from the nonsurviving twin. The resulting protuberance presented a reconstructive challenge. The Committee on Clinical Investigation, Children’s Hospital, Boston, approved reporting of this experience without review. CASE REPORT Antenatal ultrasound imaging showed a 29-year-old woman to be carrying thoracopagus twins. Echocardiography showed a structurally normal single heart oriented in a mesocardia position with normal great vessels to only one fetus. The apex of the heart protruded into the other twin, but there were no direct vascular connections to this fetus, which had only a rudimentary single, thin-walled, slowly contracting cardiac structure. In a unique conjoined presentation of the TRAP sequence, the acardiac fetus received arterial perfusion from the pump twin through the single umbilical cord. Blood was pumped from the single heart to the placenta by way of one set of umbilical arteries and returned up the other to perfuse the acardiac twin. Retrograde flow in the aorta of the acardiac twin was seen. Nearly immediate neonatal demise was predicted, because the arterial perfusion to the acardiac twin would be interrupted at the moment of umbilical cord ligation. This information facilitated planning of immediate separation after cesarean section delivery with survival of the 1 twin who was potentially independently viable, but doomed to perish along with her sister if unseparated. Because the functionally acardiac twin could not survive, the incision for separation was performed far toward her side of the fusion plane. After division of the fused liver, the flaps of anterior thoracoabdominal tissues from the sacrificed twin were rotated anteriorly to close the ventral tissue deficit of the survivor. The undisturbed protuberant heart was protected by and covered with a cagelike structure created from the autologous ribs and soft tissues of the opposite twin (Fig 1).1 After the infant made a complete recovery and was developing normally, we sought to determine whether the chest wall protuberance could be eliminated. Multiplanar electrocardiogram-gated magnetic resonance images were obtained to assess the spatial relationships between the heart and surrounding organs and inflow vessels (Fig 2). Journal of Pediatric Surgery, Vol 37, No 3 (March), 2002: pp 515-517
INDEX WORDS: Conjoined twins, thoracopagus, chest wall reconstruction, ectopia cordis.
DISCUSSION
Thoracopagus conjoined twins with shared cardiac structures never have been separated to successfully yield 2 long-term surviving children.2 Only 1 long-term survivor has been reported previously after separation of hearts joined at the atrial level.3 Although our twins had a single heart anatomically located between the 2, it had 4 normal chambers and great vessel connections to only 1 twin. Normal cardiac physiology after separation alFrom the Departments of Surgery and Cardiology, Children’s Hospital and Harvard Medical School, Boston, MA. Presented at the 32nd Annual Meeting of the American Pediatric Surgical Association, Naples, Florida, May 20-23, 2001. Address reprint requests to Steven J. Fishman, MD, 300 Longwood Ave, Boston, MA 02115. Copyright © 2002 by W.B. Saunders Company 0022-3468/02/3703-0044$35.00/0 doi:10.1053/jpsu.2002.30867 515
516
FISHMAN ET AL
thoracic ectopia cordis. Autologous tissue coverage by most means typically produces excessive compression of the heart, limiting cardiac output, either by impeding cardiac filling or kinking great vessels.5 There have been few reported survivors of thoracic ectopia cordis.6-8 The intrathoracic cavity has been shown to be diminished in size in these patients.9 Closure in a single stage was
Fig 1. (A) Thoracopagus twins at birth. (B) Appearance of child after separation and coverage of heart with ribs and soft tissues of conjoined twin.
lowed for survival of 1 child. However, the cardiac location presented anatomic challenges similar to those seen in thoracic ectopia cordis: the need for tissue coverage and the protuberant heart. Coverage of body wall defects after separation of conjoined twins with 2 separate hearts has been addressed by the use of prosthetic materials and preoperative tissue expansion.4 Because only 1 surviving child was possible in our case, there was adequate autologous tissue from the other twin to close the defect. Conjoined twins with separate hearts do not have significant malpositioning of the heart. However, protrusion of the heart is the predominant difficulty in
Fig 2. ance.
MRI shows orientation of heart in chest wall protuber-
CONJOINED TWINS
517
Fig 4. Appearance after cardiac relocation and chest wall reconstruction.
thoracopagus conjoined twins with a single heart should include careful observation for reversed flow in the aorta of one twin, suggesting the TRAP sequence. Up to 40% of conjoined twins are stillborn and another 30% survive less than 1 day.10 Twins with an unrecognized TRAP sequence would face certain early demise without immediate separation. If loss of one twin is certain, proper incision placement for separation allows for coverage with autologous tissue. It may be possible to increase the space in the chest by lowering the diaphragms, thus, allowing the protuberant heart to be relocated in the case of either a separated conjoined twin or an infant with ectopia cordis. REFERENCES
Fig 3. (A) Clam-shell appearance of protective cage of ribs from twin covering heart. (B) Split cage over heart relocated into chest. (C) Reconstructed anterior chest wall using upper left conjoined ribs.
achieved by Amato et al8 in part by mobilization of the diaphragms inferiorly. Our case shows several points. In utero evaluation of
1. Norwitz ER, Hoyte LPJ, Jenkins KJ, et al: Separation of conjoined twins with the twin reversed-arterial-perfusion sequence after prenatal planning with three-dimensional modeling. N Eng J Med 343:399-402, 2000 2. Chiu CT, Hou SH, Lai HS, et al: Separation of thoracopagus conjoined twins. A case report. J Cardiovas Surg 35:459-62, 1994 3. Synhorst D, Matlak M, Roan Y, et al: Separation of conjoined twins joined at the right atria. Am J Cardiol 43:662-665, 1979 4. Zubowicz VN, Ricketts R: Use of skin expansion in separation of conjoined twins. Ann Plast Surg 20:272-276, 1988 5. Shamberger RC, Welch KJ: Sternal defects. Pediatr Surg Int 5:156-164, 1990 6. Saxena NC: Ectopia cordis child surviving: Prosthesis fails. Pediatric News 10:3, 1976 7. Dobell ARC, Williams HB, Long RW: Staged repair of ectopia cordis. J Pediatr Surg 17:353-358, 1982 8. Amato JT, Cotroneo JV, Gladiere R: Repair of complete ectopia cordis (video presentation) presented at the American College of Surgeons Clinical Congress. Chicago, IL, 1988 9. Haynor DR, Shuman WP, Brewer DK, et al: Imaging of fetal ectopia cordis: Roles of sonography and computed tomography. J Ultrasound Med 3:25-7, 1984 10. Edmonds LD, Layde PM: Conjoined twins in the United States, 1970-1977. Teratology 24:301-308, 1982