1 research outputs found
Separation of Conjoined Hearts in Thoracopagus Twins
<p><b>Introduction</b></p>
<p>Eight hours after delivery of thoracopagus twins, the right twin
developed circulatory failure forcing an emergency separation to save the left twin.
The twins had conjoined livers and conjoined hearts in a common pericardial
cavity, and they appeared to have no ventricular-level fusion. </p>
<p><b>Procedure</b></p>
<p>Surgery was performed on the second day of life using
general anesthesia and full invasive monitoring. The twins were placed with the
ventral side uppermost; the ventral side being the side with the greater
inter-areolar distance. After skin preparation and draping, an incision was
made along the line of somatic fusion and the abdomen was entered to separate
the conjoined livers and intestines.</p>
<p>Moving to the chest, the two diaphragms were conjoined and
the two hearts were in a common pericardial cavity. The heart of the right twin
was clearly hypoplastic but had good contractility. The preoperative
echocardiogram had shown this twin’s heart to have functionally single
ventricle morphology. The left twin had a normal-sized four-chambered heart on
echocardiogram, and this appeared to be the case at surgery. The caval and
pulmonary venous connections were separate and normal for each heart. At the
atrial level, a short tubular bridge of myocardium connected the two atrial
masses. There was no connection at the ventricular level and so the hearts
could be separated by simple division of the atrial bridge. The hearts were
thus separated completely. Subsequently, the surgical incision was carried
round dorsally through the layers of the chest and abdominal walls to effect
complete separation of the twins. Care was taken to commit as much of the
conjoined chest and abdomen to the healthy twin to limit the potential for
flail chest and abdominal compartment syndrome.</p>
<p>The chest wall of the healthy twin was reconstructed with a
mesh as shown in the video. The abdomen was closed primarily without tension.</p>
<p><b>Outcome </b></p>
<p>As expected, the heart of the right twin could not support
an adequate cardiac output, and death ensued shortly after separation. The
apparently healthy twin remained hemodynamically stable postoperatively,
maintaining adequate tissue perfusion without inotropic support. However, her
respiratory function remained suboptimal and deteriorated gradually into
refractory respiratory failure until her death on the eighth postoperative day.</p>
<p><b>Comment</b></p>
<p>Three reports from the UK [1], USA [2], and South Africa [3]
represent the largest surgical experience of separation of conjoined hearts in
thoracopagus twins gathered over three to four decades. Our limited experience
fits fairly well with these reports: in the current era, successful surgical
separation of conjoined hearts in thoracopagus twins remains largely elusive.
Pulmonary hypoplasia ostensibly results from the lungs having to develop within
the thoracic volume of half a conjoined body cavity. In addition, impaired
ventilatory mechanics resulting from postoperative flail chest, pneumothoraces,
a restrictive chest wall, and respiratory infection all contribute to make
respiratory insufficiency an important confounder of survival after an
apparently successful surgical separation.</p>
<p><b>References</b></p>
<p>1. Andrews RE, McMahon CJ, Yates RW, et al.
Echocardiographic assessment of conjoined twins. <i><a href="https://doi.org/10.1136/hrt.2005.069682">Heart. 2006;92(3):382-387</a></i>.</p>
<p>2. Thomas Collins R 2nd, Weinberg PM, Gruber PJ, St John
Sutton MG. Conjoined hearts in thoracopagus twins. <i><a href="https://doi.org/10.1007/s00246-011-0125-3">Pediatr Cardiol. 2012;33(2):252–257</a></i>.</p>
<p>3. Rode H, Fieggen AG, Brown RA, et al. Four decades of
conjoined twins at Red Cross Children's Hospital--lessons learned. <a href="https://www.ncbi.nlm.nih.gov/pubmed/17077920"><i>S Afr Med J</i>. 2006;96(9 Pt 2):931-940</a>.</p