Congenital heart defects in conjoined twins: outcome after surgical separation of thoracopagus

Phenotypically Discordant Anomalies in Conjoined Twins: Quirks of Nature Governed by Molecular Pathways?

A multitude of additional anomalies can be observed in virtually all types of symmetrical conjoined twins. These concomitant defects can be divided into different dysmorphological patterns. Some of these patterns reveal their etiological origin through their topographical location. The so-called shared anomalies are traceable to embryological adjustments and directly linked to the conjoined-twinning mechanism itself, inherently located within the boundaries of the coalescence area. In contrast, discordant patterns are anomalies present in only one of the twin members, intrinsically distant from the area of union. These dysmorphological entities are much more difficult to place in a developmental perspective, as it is presumed that conjoined twins share identical intra-uterine environments and intra-embryonic molecular and genetic footprints. However, their existence testifies that certain developmental fields and their respective developmental pathways take different routes in members of conjoined twins. This observation remains a poorly understood phenomenon. This article describes 69 cases of external discordant patterns within different types of otherwise symmetrical mono-umbilical conjoined twins and places them in a developmental perspective and a molecular framework. Gaining insights into the phenotypes and underlying (biochemical) mechanisms could potentially pave the way and generate novel etiological visions in the formation of conjoined twins itself.

Conjoined thoracopagus twins: A systematic review of the anomalies and outcome of surgical separation

Introduction

Conjoined twin is an extremely rare condition and requires a thorough knowledge of anatomy, and a multidisciplinary approach is essential to successfully separate the twins. Thoracopagus twins lie face to face and are attached from chest to upper abdomen. They are the most common among all the varieties but have a poor survival rate.

Materials and Methods

This study is a review of literature from 2019 to the oldest via PubMed and Google Scholar using keywords: Conjoined twins, Thoracopagus twins, Thoracoomphalopagus and Thoraco-omphalopagus twins. The articles were reviewed for the description of the anatomy of shared organs, management and outcome of these twins.

Results

One hundred and fifty-eight sets of thoracopagus and thoraco-omphalopagus twins including our twins were included in this study. Out of 158 reported thoracopagus twin sets in literature, with M: F ratio of 1:2.3, 71 sets were found to be non-operable and all of them subsequently expired; 82 sets were operated upon, out of which 83 babies survived, suggesting an overall surgical success rate of about 50%.

Conclusion

Thoracopagus twins have a dismal prognosis. The most important decisive parameter for successful separation is the extent of sharing of organs between twins. The role of a motivated multidisciplinary team is also indispensable and cannot be overemphasised.

Surgical Repair of Complete Common Atrioventricular Canal in a Conjoined Twin Following Separation

Congenital heart disease (CHD) is common in conjoined twins but reports of surgical repair in this population are rare. We present the case of a conjoined twin diagnosed prenatally with a complete common atrioventricular canal defect (CAVC). Due to wound complications from twin separation, definitive repair was deferred and pulmonary arterial banding was performed initially. At 6 months, a complete CAVC repair was performed. The present case adds to the literature on successful cardiac surgical repairs in conjoined twins.

Use of virtual reality for pre-surgical planning in separation of conjoined twins: A case report

We describe the use of virtual reality technology for surgical planning in the successful separation of thoracopagus conjoined twins. Three-dimensional models were created from computed tomography angiograms to simulate the patient's anatomy on a virtual stereoscopic display. Members of the surgical teams reviewed the anatomical models to localize an interatrial communication that allowed blood to flow between the two hearts. The surgical plan to close the 1-mm interatrial communication was significantly modified based on the pre-procedural spatial awareness of the anatomy presented in the virtual visualization. The virtual stereoscopic display was critical for the surgical team to successfully separate the twins and provides a useful case study for the use of virtual reality technology in surgical planning. Both twins survived the operation and were subsequently discharged from the hospital.

'Mutiny on the crown': two cases of rare cephalic malformations

The presentation and management of two bizarre congenital cephalic curiosities at the two extremes of the clinical spectrum are discussed herewith. Case 1: presented to us as a neonate with a scalp swelling mirror-imaging her head and face. The journey from clinics to wards and to the operation theatre and to her home is introspected. Case 2: presented to us as dicephalous dibrachius dipus parapagus conjoined twins. The detailed work-up of individual organ systems, the multidisciplinary approach to management and the final outcome are discussed. This is an unsolved mystery for the anatomists, paediatric surgeons, radiologists and the medical fraternity at large.

Dicephalus Parapagus Conjoined Twins Diagnosed by First-Trimester Ultrasound

Conjoined twins are a rare phenomenon, occurring in 1% of monochorionic twin gestation, with an incidence of 1 : 50 000 to 1 : 100 000. Many conjoined twins have abnormalities incompatible with life, so early prenatal diagnosis is very important for optimal management of both pregnancy and delivery. We report a case of dicephalus parapagus conjoined twins, sharing a single heart, diagnosed at 12 weeks' gestation. With early ultrasound diagnosis, we were able to provide appropriate and timely prenatal counseling to the family.

Conjoined twins-thoraco-omphalopagus (type A)

A case of conjoined twins discovered by routine transabdominal ultrasound examination at 16 weeks gestation in a 19-year-old multigravid female. They were joined at the chest and the abdomen and had one functional heart. The pregnancy was terminated by caesarean section at 19 weeks gestation with approval from the family.

The management of conjoined twins: Cardiology assessment

Structural cardiac defects occur in at least 1 twin in about 75% of conjoined twins with thoracic level fusion. Outcomes after surgical separation of thoracic level conjoined twins have been favorable when the hearts have been separate. However, even in this situation, the outlook is poor for an individual twin with an important cardiac defect. Arterial anastomosis between twin circulations is an important additional consideration, with poor outcomes for perfusion recipient twins. Surgical separation is contraindicated when ventricular level cardiac fusion exists. Cardiac assessment is a key component of prenatal counseling.

Cardiothoracic surgery

Conjoined twins often have complex cardiac anomalies associated with other congenital defects. The correct cardiac diagnosis delineates the degree of cardiac fusion and the feasibility of separation. The outcome in twins with fused hearts remains poor.

Anesthetic management for separation of thoracopagus twins with complex congenital heart disease: a case report

Although thoracopagus twins joined at the upper chest are the most common type of conjoined twins, the separation surgery in these cases has a higher mortality rate. Here, we describe an anesthetic management approach for the separation of thoracopagus conjoined twins sharing parts of a congenitally defective heart and liver. We emphasize the importance of vigilant intraoperative hemodynamic monitoring for early detection of unexpected events. Specifically, real-time continuous monitoring of cerebral oximetry using near-infrared spectroscopy allowed us to promptly detect cardiac arrest and hemodynamic deterioration.

Cardiac fusion and complex congenital cardiac defects in thoracopagus twins: diagnostic value of cardiac CT

Most thoracopagus twins present with cardiac fusion and associated congenital cardiac defects, and assessment of this anatomy is of critical importance in determining patient care and outcome. Cardiac CT with electrocardiographic triggering provides an accurate and quick morphological assessment of both intracardiac and extracardiac structures in newborns, making it the best imaging modality to assess thoracopagus twins during the neonatal period. In this case report, we highlight the diagnostic value of cardiac CT in thoracopagus twins with an interatrial channel and complex congenital cardiac defects.

A chick embryo with a yet unclassified type of cephalothoracopagus malformation and a hypothesis for explaining its genesis

Cephalothoracopagus embryos are conjoined twins, who share parts of their heads, necks and bodies. Our study aims at presenting a detailed morphological analysis of a cephalothoracopagus chick embryo of developmental stage 31. Because none of the existing theories can explain the genesis of the phenotype of this embryo, we also suggest a hypothesis, which explains it. Beside the cephalothoracopagus embryo, we investigated five control embryos. With the aid of the high-resolution episcopic microscopy (HREM) technique, we created digital volume data and three-dimensional (3D) computer models of the organs and arteries of the embryos. We used the 3D models for topological analysis and for measuring the diameters of the great intrathoracic arteries. The malformed embryo showed two body backs, each containing a notochord, spinal cord and dorsal aorta. The body backs continued into separated lower bodies. The embryo had a single, four-chambered heart, single respiratory tract and single upper alimentary tract. The topology of the pharyngeal arch arteries was normal, and the diameters of these arteries were similar to that of the control embryos. We classified the embryo we investigated as a yet unknown malformation and suggest a hypothesis explaining its genesis.

Conjoined hearts in thoracopagus twins

This study aimed to identify the anatomic and pathologic structural cardiac abnormalities in conjoined twins and to focus on those that have prevented the successful separation of conjoined hearts. A retrospective review was undertaken to examine consecutive cases of thoracopagus conjoined twins with conjoined hearts evaluated at The Children's Hospital of Philadelphia from 1 January 1980 through 6 October 2008. The records included autopsy and surgical findings as well as clinical reports. The study group included nine sets of conjoined twins with a mean gestational age at birth of 33.8 ± 5.5 weeks. Three twin pairs were stillborn. Five twin pairs died afterward. One pair died of cardiopulmonary failure. The median age at death was 22 days (range, 0-345 days). Major congenital heart disease was present in 94.4% (17/18) of the hearts, and 72.2% (13/18) of the hearts had single-ventricle physiology. Total anomalous pulmonary venous return occurred in 39% (7/18) of the cases. The clinical outcome for thoracopagus twins with conjoined hearts remains poor because of inability to separate conjoined and single ventricles. Surgical nonintervention and palliative care should be strongly considered for these patients.

Prenatal diagnosis of dicephalic parapagus conjoined twins

Dicephalic parapagus is a rare anomaly of monochorionic twinning. We present prenatal diagnosis of this anomaly with ultrasonography and magnetic resonance imaging. She was at the 19th week of gestation. Even if earlier diagnosis is possible, this was her first examination unfortunately. Baby had two head and a common trunk. This is one of the rarest twinning. Termination of pregnancy is performed and baby is delivered by cesarean section. Imaging findings of the case are illustrated and discussed with the autopsy findings.

Echocardiographic assessment of conjoined twins with congenital heart disease in Shanghai

BACKGROUND

The aim of this study is to improve the diagnosis of congenital heart disease in conjoined twins using echocardiography.

METHODS

Six sets of conjoined twins at Shanghai Children's Medical Center and Xin-Hua Hospital from 1980 to 2006 were assessed retrospectively. Cardiac anomalies of varying degrees of severity were first evaluated using 2D echocardiography. Tissue Doppler imaging (TDI) was then performed if fused ventricles were suspected. Peak systolic velocities, peak systolic strain rates, and peak systolic strains at the fused myocardium were quantitatively measured using strain rate imaging (SRI). If the M-mode echocardiographic image was poor or difficult to measure, the myocardial performance index (MPI) of the left ventricle was calculated.

RESULTS

Intracardiac anomalies were diagnosed correctly using echocardiography and confirmed by surgical findings. Cardiac functional assessment using MPI demonstrated heart failure in three out of the eight individuals. Subtle conjunction of the ventricles, however, were more difficult to visualize and two sets of conjoined twins with fused hearts could not be clearly demonstrated by echocardiography. In one case of suspected ventricular wall conjunction, TDI showed separate ventricular myocardia which was confirmed at surgery.

CONCLUSIONS

Intracardiac anomalies and ventricular function can be readily demonstrated by echocardiography, but subtle conjunction of the ventricles may be more difficult to visualize. TDI may be required if there is uncertainty about the degree of cardiac fusion.