Putting our heads together: The future of craniopagus twin separation.

Computer-assisted design and computer-assisted modeling (CAD/CAM), virtual surgical planning (VSP) and augmented/virtual reality (AR/VR) aid our ability to plan and perform complex craniofacial procedures. This study seeks to define the role of the aforementioned techniques in the separation of craniopagus conjoined twins. Six teams were identified who had successfully performed craniopagus twin separation with the use of CAD/CAM, VSP and/or AR/VR. Surgeons involved in separating craniopagus twins have increasingly utilized tools such as CAD/CAM models, VSP and AR/VR to plan and execute successful separation, and these tools are associated with higher success rates than historical controls.

Monochorionic triplet pregnancy complicated by conjoined twins and early twin-twin transfusion syndrome.

BACKGROUND: The condition of monozygotic, monochorionic triplet fetuses with a pair of conjoined twins is extremely rare (close to one in a million births), presents challenges in its management, and with poor prognosis. CASE REPORT: We report a case of monochorionic diamniotic triplet pregnancy, ultrasound at 14 weeks shows a pair of conjoined thoracopagus fetuses, sharing heart, liver, and umbilical cord, in addition to omphalocele. The third fetus, without malformations, presents signs of early heart failure compatible with twin-to-twin transfusion syndrome. It was decided to carry out expectant management where at 18 weeks, intrauterine death of the three fetuses occurs. An abortion is performed by hysterotomy. CONCLUSIONS: The treatment in these cases is discussed, three management options have been proposed: expectant management, selective reduction of the conjoined fetuses, or termination of the pregnancy. A review of the literature found only 12 cases with this combination of pathologies, in which only 3 normal fetuses (25%) survived and none of the conjoined twins survived. To our knowledge, this case is the first of a monochorionic triplet pregnancy with conjoined fetuses complicated with early twin-to-twin transfusion.

Morphological variations on vital systems in a conjoined twin.

Conjoined twins (CTs), popularly referred to as Siamese twins, are a rare anomaly due to monochorionic and monoamniotic twin pregnancies. Dicephalus dibrachius dipus, a type of parapagus conjoined twin which is characterized by possessing two arms, two legs, a single trunk and two heads, epidemiologically, is an even rarer occurrence of CTs. In this article, a rare, well-preserved anatomical specimen of a dicephalus dibrachius dipus conjoined twin is presented. This study was conducted in a specimen which is part of the collection of the Embryology Museum of the institution by donation and approved by the Research Ethics Committee (REC). The female conjoined twins were born at full-term by cesarean section in the 1970s and died hours after birth. A thorough anatomical description was made through observational analysis, computed tomography and 3D reconstructed images. Major abnormalities were observed in the cardiovascular, respiratory and digestive systems. The internal anatomy exhibited a heart with three atria, two ventricles, two aortic arches, two pulmonary arteries, one innominate venous trunk and a respiratory system with two tracheas and four lungs. No other report was similar to our three atria heart description. This article provides a thorough anatomical description of all systems, which is valuable information for further studies on CTs.

Anterior Chest Wall Reconstruction After Separation of Thoraco-Omphalopagus Conjoined Twins With Cadaveric Rib Grafts and Omental Flap.

BACKGROUND: Anterior chest wall defects have a wide range of etiologies in the pediatric population, ranging from infection, tumor, and trauma to congenital diseases. The reconstructive goals include restoring skeletal stability, obliterating dead space, preserving cardiopulmonary mechanics, and protecting vital underlying mediastinal organs. Although various reconstructive methods have been described in the literature, selecting the optimal method is challenging for the growing pediatric skeleton. Here, we report a case of previously thoraco-omphalopagus twins who underwent successful separation and reconstruction and presented for definitive anterior chest wall reconstruction. METHODS: A pair of previously thoraco-omphalopagus conjoined twins underwent definitive anterior chest wall defect reconstruction using cadaveric ribs and omental flap. Twin A received 2 cadaveric ribs, whereas twin B had a much larger sternal defect that required 3 cadaveric ribs combined with an omental flap for soft tissue chest coverage. Both twins were followed up for 8 months. RESULTS: Twin A's postoperative course was uneventful, and she was discharged on postoperative day 6. Twin B's course was complicated, and she was discharged on supported ventilation on postoperative day 10. At 8 months postoperatively, both twins healed well, and chest radiographs confirmed the stability of the chest reconstructions. The rib grafts in the twin with a tracheostomy were not mobile, and the patient had a solid sternum with adequate pulmonary expansion. The construct initially did not facilitate pulmonary functioning, but after a healing process, it eventually allowed for the twin with the tracheostomy who required pulmonary assistance to no longer need this device. CONCLUSIONS: Cryopreserved cadaveric ribs and omental flaps offer safe and reliable reconstructive methods to successfully reconstruct congenital anterior chest wall skeletal defects in the growing pediatric population. The involvement of multidisciplinary team care is key to optimizing the outcomes.

Symmetrical parapagus diprosopus: A comparative, computed tomographic, and pathoanatomical study of a new case in domestic pig.

BACKGROUND: Parapagus diprosopus are conjoined twins characterized by craniofacial duplication and only one body, representing one of the rarest types of these twins. Their occurrence has been recorded in different species of vertebrates, including humans, but few cases have been studied in domestic pigs. CASE: A pair of conjoined twin pigs was studied using x-rays, computed tomography, and necropsy. The abnormalities found were compared with those of the rare swine cases presented in the literature as well as with other species, and the different etiopathogenetic possibilities were addressed. The degree of duplication of the head bones decreased caudally, as did that of the structures of the central nervous system. In the two oral cavities, there was a complete cleft palate. All the cervical vertebrae and thoracic vertebrae up to T3 were partially duplicated. The heart and great vessels were normal, as were the other thoracic and abdominal organs. CONCLUSIONS: The conjoined twin pigs of this study are a case of parapagus diprosopus tetraophthalmus triotus, presenting the same pattern of abnormalities of human diprosopus and that of other species. The scarcity of detailed studies on craniofacial duplication in pigs and the lack of a definitive explanation on the etiology and pathogenesis of conjoined twins shows the need for further research and the publication of more cases.

The Management of Acardiac Twinning: Twin Reverse Arterial Perfusion Sequence - An International Survey.

INTRODUCTION: The optimal approach and therapy method for the acardiac twin with a reverse arterial perfusion sequence has not yet been established. The aim of this study was to determine the clinical practice patterns among international fetal therapy units in their management of these cases. METHODS: A survey was sent to fetal centers across the world via email between December 2020 and December 2021. RESULTS: Responses were obtained from 77% contacted centers. The most frequent ultrasound variables used in the evaluation of twin reverse arterial perfusion sequence include echocardiographic assessment of the pump twin and umbilical artery Doppler waveforms in the acardiac and pump twins, in 90% and 80% of the centers, respectively. Most centers in Europe and Latin America propose an in utero intervention in all cases. Most centers in Europe and Latin America prefer interstitial laser ablation, whereas radiofrequency ablation (RFA) is preferred in North America. The earliest gestational age for an intervention is on mean 13 weeks in Europe, which is earlier than the other geographic areas (p = 0.001). CONCLUSIONS: Most centers agreed that antenatal evaluation should include echocardiography along with the UA Doppler waveform measurements, and the most frequently used interventions were interstitial laser ablation or RFA at a median between 14 and 26 weeks.

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.

Twin Research and Human Genetics - News, Views & Comments: Memoirs and Autobiographies by Twins: Research Angles and Human Interest/Twin Research Reviews: Fetal Reduction in Twin Pregnancy; Twins' Personality and Military Service; Growth Restriction in Twins; Advances in Conjoined Twin Separation/Media Reports: Update on Scientist Who Performed Gene Editing on Twins; Twins From 33-Year-Old Embryos; Twins' Outcomes From Dietary Differences; Fraternal Twins With the World's Largest Height Difference; Twin Home Experts Conquer Rat Infestation.

Twins' memoirs and autobiographies both enlighten and entertain. These works, often overlooked by researchers, may suggest new avenues for investigation, such as nonshared environmental events that propel twins in different directions. Of course, MZ twins' generally parallel experiences and DZ twins generally criss-crossing paths are the bases of fascinating life stories. The following sections examined recent research on fetal reduction in twin pregnancy, twins' personality and military service, growth restriction in twins, and advances in conjoined twin separation. This article closes with reports of a scientist who performed gene editing on twins, a twin conception from 33-year-old embryos, twins' physical outcomes from dietary differences, fraternal twins with the world's largest height difference and the Twin Home Experts who conquer rat infestation in New York.

Postnatal imaging of conjoined twins: a customized multimodality approach.

Medical imaging plays a crucial role in the management of conjoined twins. The role of imaging is to explore the anatomy, outline the shared organs and determine whether surgery is feasible. It also serves as a roadmap for successful separation. Additionally, imaging helps with counseling parents about prognosis. This review aims to illustrate recent advances in different imaging modalities and their role in the management of the various types of conjoined twins with an emphasis on relevant tips for optimal imaging.

Thoracopagus conjoined twins.

OBJECTIVE: We present a case report of conjoined twins. CASE REPORT: Secundigravida nullipara, 28-years old, admitted for profuse bleeding at 13 weeks of gestation. Ultrasound confirmed vital pregnancy of conjoined twins - thoracopagus. After prenatal diagnostic consultation the patient decided for termination of pregnancy. Molecular analysis confirmed a female fetus without any chromosomal anomalies. CONCLUSION: The occurrancce of conjoined twins is very rare. Early prenatal ultrasound diagnosis plays an important role. Presented case report describes conjoined twins with poor prognosis because of one shared malformed heart.

Craniorachipagus symmetric conjoined twinning: Identification of a fourth case and delineation of the phenotype.

BACKGROUND: Symmetric craniorachipagus is an exceedingly rare type of bi-umbilical conjoined twinning, known from only three scantily described cases. CASE: We identified a fourth, previously described case that was misdiagnosed as janiceps and as pygopagus. It concerned dorsally conjoined twins that were part of a triplet pregnancy, spontaneously born at 22 weeks of gestation. Radiography confirmed union at the occipital craniums and the thoracolumbar vertebral columns. Both twins had their own separate umbilical cords. To delineate the phenotype of craniorachipagus and to differentiate it from rachipagus without cranial involvement, we compared the present case with the previous three reported cases and with the historical literature concerning comparable conditions. Furthermore, we discuss why exceedingly rare conditions such as these are presently underreported in the literature. CONCLUSION: Symmetric craniorachipagus is a type of bi-umbilical conjoined twinning, to date represented by four confirmed cases that share a similar phenotype. This includes dorsal conjunction at the sides of the occipital craniums and the vertebral columns, in the absence of any visceral connections. Details on its etiopathogenesis and apparent lethality await additional case investigations. No unequivocally confirmed cases of symmetric rachipagus without cranial involvement have been reported and its existence in humans has yet to be proven.

Incidental Intraoperative Diagnosis of Term Conjoined Twins: A Case Series.

Conjoined twins (Siamese twins) represent the rarest form of twin pregnancy. Reported here are two rare cases of conjoined term twins presented to the department of Obstetrics and Gynaecology within 3 months. The first case, 32 years of gravida 6 parity 5 referred from periphery after full trial of labour following multi-organ dysfunction and term intrauterine dead twins. Intraoperatively it was dead conjoined thoraco-omphalopagus females. The patient died after 3 days following multiorgan dysfunction syndrome and disseminated intravascular coagulation. The second case, 22 years gravida 2 parity 1 also referred from periphery in second stage of labour with diagnosis of 39 weeks intrauterine dead twins with obstructed labour, delivered by caesarean with intraoperative conjoined dead females of thoracophagus type. Twins are high-risk pregnancy. This rare diagnosis with complications could have been prevented by regular antenatal checkups, ultrasonography performed by radiologists and early referral antenatally in labour along with multidisciplinary approach. Keywords: conjoined; monozygotic twinning; siamese twins; twins.

Integrated multiomics reveal the molecular characteristics of conjoined twin fetuses.

RESEARCH QUESTION: Are there any differences between conjoined twin fetuses at the molecular level? DESIGN: Skin tissues were collected from thoracopagus conjoined twins at 15+4 weeks of gestation. The skin tissues were collected from the thigh side of conjoined twins after the abortion procedure. All specimens were obtained after written informed patient consent and were fully anonymized. All relevant ethical regulations were followed. Every specimen underwent multiomics sequencing analysis to determine associations among the DNA methylome, transcriptome and mutations in the exon regions in the conjoined twins. RESULTS: The global methylation pattern was similar in the two fetuses of conjoined twins, while significant differences were seen in local regions such as CpG islands (P = 0.026), enhancers (P < 0.001) and various repetitive elements (P < 0.05), which showed significant differences. The conjoined twins also differed in genes related to growth and development, cellular component morphogenesis and cellular stress, both in terms of DNA methylation levels and gene expression levels. Exon data analysis revealed that the common mutations in conjoined twins mainly occurred in neural development, lipid metabolism and microtubule morphogenesis. Specific mutations were associated with cellular component biosynthesis, behaviour and germ cell development. CONCLUSION: Conjoined twins were similar to each other globally, but there were significant differences related to growth and development, cellular component morphogenesis and cellular stress. The current study reveals the molecular features of conjoined twins for the first time, laying the foundation for future exploration of the mechanism of conjoined twins.

Symmetrical parapagus diprosopus tetrophthalmos in a bovine calf, with computed tomography imaging, and review of craniofacial duplications.

Diprosopia, a congenital defect process also known as craniofacial duplication, is well-recognized in humans and has also been reported in numerous animal species. Here we describe a case of diprosopia in a live mixed-breed beef calf. We used computed tomography imaging to characterize internal and external abnormalities which, to our knowledge, have not been reported in any diprosopic veterinary species. Additional diagnostic tools included postmortem examination and histopathology. This case highlights distinct anatomic features associated with diprosopia and underscores the unique challenges associated with classifying and managing fetal malformations.

The role of intraoperative neuromonitoring in pygopagus separation: two-institution experience in Indonesia.

INTRODUCTION: Pygopagus comprises 17% of all conjoined twin cases. Survival rate is higher compared to other variations of conjoined twins, but separation is a great challenge due to multiorgan involvement. Intraoperative neuromonitoring (IONM) used aims to aid operator in preserving as much function as possible. CASE PRESENTATIONS: The authors reported 2 pairs of pygopagus separation. Intraoperatively, motor-evoked potential (MEP) and sensory-evoked potential (SEP) were used in all patients. Three patients survived in which all had transient motor deficits. Urinary retention was reported in one patient. One patient died 2 weeks after separation as twins only had one kidney which was spared for the healthier twin. DISCUSSION: IONM was used to guide operator in dissecting, identify the ownership of the neural structures, and determine the safest point to separate in pygopagus separation. Despite the normal MEP and SEP recordings, transient motor weakness may still occur transiently. The motor tract development of children is achieved in adolescence, making MEP less accurate. However, the reliability of MEP increases when it is combined with SEP. Autonomic function monitoring such as bulbocavernosus reflex (BCR) could not be assessed due to the unavailability of the probe. CONCLUSION: IONM can aid operator in pygopagus separation during determining the origins of the structure, dissecting, and cutting the neural structures. Normal MEP interpretations are still possible to correlate with transient deficits, but reliability can be improved with the use of SEP. In surgeries involving the lower spine level, BCR monitoring is recommended to avoid autonomic deficits.

Separation of conjoined spinal cords in symmetrical pygopagus twins using intraoperative neuromonitoring: pearls and pitfalls.

Pygopagus twin is a rare congenital malformation with a worldwide incidence of 1in 200,000. Few literature reports are published regarding the matter. In some cases, neuromonitoring is essential for safe surgical separation. We believe it is important to share our challenges and nuances in order to minimize obstacles one might encounter. We utilized neuromonitoring during our separation of both twins, and we planned a multidisciplinary approach and efficient communication system with the other teams in order to plan a successful, safe, and timely separation of the twins. We seek to highlight not our success but rather the obstacles and challenges we encountered during the separation of pygopagus twins in our institute using neuromonitoring for future reference.

Brain malformations in diprosopia observed in clinical cases, museum specimens and artistic representations.

BACKGROUND: Diprosopus is a rare malformation of still unclear aetiology. It describes a laterally double faced monocephalic and single-trunk individual and has to be distinguished from the variant Janus type diprosopus. RESULTS: We examined seven double-faced foetuses, five showing true diprosopus, and one each presenting as monocephalic Janiceps and parasitic conjoined twins. Four of the foetuses presented with (cranio)rachischisis, and two had secondary hydrocephaly. Three foetuses showed cerebral duplication with concordant holoprosencephaly, Dandy-Walker cyst and/or intracranial anterior encephalocele. In the Janiceps twins, cerebral duplication was accompanied by cerebral di-symmetry. In the parasitic twins the cyclopic facial aspects were suggestive of concordant holoprosencephaly. In one of the true diprosopus cases, pregnancy was achieved after intracytoplasmic sperm injection. Whole-exome sequencing, perfomed in one case, did not reveal any possible causative variants.The comparison of our double-faced foetuses to corresponding artistic representations from the Tlatilco culture allowed retrospective assignment of hairstyles to brain malformations. CONCLUSION: Brain malformations in patients with diprosopus may not be regarded as an independent event but rather as a sequel closely related to the duplication of the notochord and neural plate and as a consequence of the cerebral and associated craniospinal structural instabilities.

Few-shot learning using explainable Siamese twin network for the automated classification of blood cells.

Automated classification of blood cells from microscopic images is an interesting research area owing to advancements of efficient neural network models. The existing deep learning methods rely on large data for network training and generating such large data could be time-consuming. Further, explainability is required via class activation mapping for better understanding of the model predictions. Therefore, we developed a Siamese twin network (STN) model based on contrastive learning that trains on relatively few images for the classification of healthy peripheral blood cells using EfficientNet-B3 as the base model. Hence, in this study, a total of 17,092 publicly accessible cell histology images were analyzed from which 6% were used for STN training, 6% for few-shot validation, and the rest 88% for few-shot testing. The proposed architecture demonstrates percent accuracies of 97.00, 98.78, 94.59, 95.70, 98.86, 97.09, 99.71, and 96.30 during 8-way 5-shot testing for the classification of basophils, eosinophils, immature granulocytes, erythroblasts, lymphocytes, monocytes, platelets, and neutrophils, respectively. Further, we propose a novel class activation mapping scheme that highlights the important regions in the test image for the STN model interpretability. Overall, the proposed framework could be used for a fully automated self-exploratory classification of healthy peripheral blood cells. The whole proposed framework demonstrates the Siamese twin network training and 8-way k-shot testing. The values indicate the amount of dissimilarity.