Shane Khan1, Steven Sankar2, Karen Sohan3, Vishal Bachan4
1 Obstetrics and Gynaecology Unit, Department of Clinical Surgical Sciences, University of the West Indies, St. Augustine Campus
2 Department of Radiology, San Fernando General Hospital, South-West Regional Health Authority, Trinidad and Tobago
3 Obstetrics and Gynaecology Unit, Department of Clinical Surgical Sciences, University of the West Indies, St. Augustine Campus
4 Department of Obstetrics and Gynaecology, San Fernando General Hospital, South-West Regional Health Authority, Trinidad and Tobago
Corresponding Author:
Shane Khan
Email: [email protected]
DOAJ: c9b01f62865446bea0950086672b1be9
DOI: https://doi.org/10.48107/CMJ.2024.09.004
Published Online: December 31, 2024
Copyright: This is an open-access article under the terms of the Creative Commons Attribution License which permits use, distribution, and reproduction in any medium, provided the original work is properly cited.
©2024 The Authors. Caribbean Medical Journal published by Trinidad & Tobago Medical Association
KEYWORDS: Conjoined twins, case report, Trinidad, low resource, management
ABSTRACT
Conjoined twins are very rare and some obstetricians may go through their career without ever managing a case. This case describes a thoraco-omphalopagus whereby the twins were joined at the chest and abdomen. Management of conjoined twins largely depends on the degree of conjoining and the availability of resources. In this case, the severity of the conjoining and lack of specialized resources resulted in managing via termination of the pregnancy. This is the first published case of conjoined twins from Trinidad and Tobago. The aim of this case report is to share our findings and management in a setting with limited resources.
INTRODUCTION
The incidence of conjoined twins is 1 in 50000 to 200000 and is associated with a predominance of the female sex with a female to male ratio of 3:1.1 Due to the rarity of conjoined twins, most obstetricians may go through their entire career without encountering a case. Similarly, due to the few numbers of cases published, guidelines on obstetric management strategies are limited. Most cases result in termination of the pregnancy or stillbirths. (2,3) Rarely, once resources are available and the degree of conjoining permits, surgical management may be an option. (4,5)
To aid in management, early detection and detailed imaging to determine the extent of conjoining is of utmost importance. In most cases, detailed ultrasound scanning will suffice with MRI scanning only being performed in specific cases. (6,7)
The classification of conjoined twins is based on the site of fusion – thoracopagus (thorax), omphalopagus (abdomen), pyopagus (sacrum), ischiopagus (pelvis), craniopagus (skull), cephalopagus (face) and rachipagus (back).6 This case describes the management of thoraco-omphalopagus conjoined twins and to the authors’ knowledge is the first such published case in Trinidad and Tobago. The purpose of this case report is to share our findings and our approach to management in a setting with limited resources.
CASE REPORT
A 34-year-old woman with a parity of 6+0 presented at 21+5 days gestational age to the specialised multiple gestation clinic at the San Fernando General Hospital (SFGH) after a routine anomaly scan at 21 weeks gestational age detected conjoined twins. She had 6 uncomplicated term vaginal deliveries and had no comorbidities or prior surgeries. This pregnancy was conceived naturally with the same partner.
On presentation to the multiple gestation clinic, a more detailed ultrasound scan was performed by the radiology and obstetric teams. An additional opinion was also sought from a private fetal medicine specialist. Ultrasound scanning showed that the foetuses were joined at the chest and abdomen (thoraco-omphalopagus) and appeared to share a common heart and liver with a single umbilical cord and one placenta. The skulls appeared separate and the limbs for each foetus appeared normal. Unfortunately, due to software and printing issues at the time, the ultrasound images are not available.
To further aid in management, an MRI was requested. The MRI findings were similar to that of the ultrasound with the main difference being that the foetuses had two separate livers but were fused at the midline (Fig. 1).
Fig. 1. A and B – T2 Coronal sequence demonstrating two gallbladders (yellow arrows) suggesting that there is independent excretion into separate loops of proximal small intestine. C – T2 Coronal sequence demonstrating joining of the foetuses from the upper thorax to the umbilicus with a common sternum, diaphragm (yellow arrowhead), and upper abdominal wall. The twins share a common heart which is seen at the midline (red arrow). A solitary umbilical artery is seen inferiorly (blue arrows).
Thereafter, a multidisciplinary team (MDT) meeting was held with the radiology, paediatric surgery, paediatric medicine, and the obstetric teams. After discussing the extent of the joining and which organs were shared, it was determined that it may be possible to perform separation surgery to save one of the twins. However, this type of specialised surgery was not available in Trinidad and Tobago and would have to be outsourced. Unfortunately, funding for this type of long-term treatment was not available at the time and the couple would have had to self-fund if feasible. As a result, the patient and husband were counselled on their management options which included termination of the pregnancy, continuation of the pregnancy or self-funding to access foreign specialised resources. The couple ultimately chose to terminate the pregnancy.
Labour was induced at 23 weeks gestational age with the use of Misoprostol tablets inserted vaginally. Although the foetuses were presenting feet first, vaginal delivery was relatively easy.
Gross inspection of the foetuses after delivery confirmed female thoraco-omphalopagus twins with a single umbilical cord (Fig. 2). Postnatal imaging was not performed to confirm the shared organs. The patient was discharged the next day with no complications.
Fig. 2. Conjoining at the chest and upper abdomen (Thoraco-omphalopagus) demonstrated with a single umbilical cord noted.
DISCUSSION
Conjoined twins are a rare type of monozygotic twinning with an incidence of 1 in 50000 to 200000 and a female to male ratio of 3:11 There are two main theories for its occurrence, the fission theory and the fusion theory. The fission theory postulates that conjoined twins arise after a single fertilised egg is incompletely split after day 12 of fertilization while the fusion theory postulates that similar stem cells fuse after complete separation of the zygote. Each theory by itself cannot account for the various findings associated with conjoined twins and thus both are often debated in the literature. (1,8)
The aetiology of conjoined twins can be broadly categorized into dorsal and non-dorsal conjunction. The dorsal conjunction usually presents with two umbilical cords and mostly separate internal organs whilst the non-dorsal conjunction usually presents with a single umbilical cord and shared internal organs.1 In addition, the classification of conjoined twins is based on the site of fusion – thoracopagus (thorax), omphalopagus (abdomen), pyopagus (sacrum), ischiopagus (pelvis), craniopagus (skull), cephalopagus (face) and rachipagus (back).(1,6) The most common type being thoraco-omphalopagus with a frequency of 28%.1 After detailed imaging and post-partum examination, this case describes thoraco-omphalopagus conjoined female twins, a form of non-dorsal conjunction. Isolated omphalopagus generally has the highest survival rate (approximately 82%) while thoracopagus and craniopagus carries the worst prognosis.9 As this case was a combined thoraco-omphalopagus, the prognosis and survival rate would have been expected to be similar to that of an isolated thoracopagus.
First trimester ultrasound scans are not only important to assist with more accurate dating of a pregnancy, but it also facilitates detection of major structural anomalies. Ideally, all pregnancies should have a first trimester dating scan at greater than 7 weeks gestational age in addition to a first trimester anomaly screening scan between 11-13+6 weeks gestational age. Early detection of any major anomalies would facilitate earlier initiation of counselling and offering termination of pregnancy. Earlier termination would pose a significantly lesser risk to the mother, both emotionally and physically. In this case, the patient did not have a dating scan nor a first trimester anomaly screening scan as she presented late for antenatal care.
One of the first steps in the management of conjoined twins is assessing what organs are being shared between the twins and to what extent. This would determine whether the twins can be separated safely or whether at least one twin would survive. Prenatal imaging is a key aspect of management. In most cases, an ultrasound scan would usually provide sufficient detail, however, an MRI can be performed if further detail is required.(1,6) In this case, both an ultrasound scan and an MRI were performed. Both showed similar findings with the only difference being that the MRI revealed two separate livers as opposed to one shared liver on the ultrasound. These findings suggested that it may be possible to perform separation surgery and possibly save at least one twin.
However, another important factor to consider in managing conjoined twins is the availability of resources to perform the initial separation surgery, in addition to the likely multiple other reconstructive surgeries that may be required. Trinidad and Tobago currently does not have the expertise required to perform these detailed surgeries and thus the option of separation surgery was not feasible.
An alternative to performing separation surgery locally would have been to outsource the resources. This could have been by inviting foreign specialists in the field to perform the procedures locally or by sending the patient to a foreign institution to have the surgeries performed. Neither of these were an option as funding was not available and the patient was not able to afford self-funding.
Another aspect that needs to be considered in the management of conjoined twins is the chance of survival and the quality of life for the twins if they are left conjoined. There are approximately less than 10 cases in case reports of conjoined twins surviving well into adulthood and even having children of their own. (10, 11) Consideration should also be given to the availability of support groups and resources in our setting to care for children with these special additional needs. Unfortunately, these specialized services are not available in our local setting.
Current laws in Trinidad and Tobago do not permit abortions. However, the common law doctrine of necessity recognizes that an abortion can be lawfully performed by a physician, in a medically appropriate setting, if the procedure is performed in good faith to preserve the life or health (including the mental health), of the mother.12 In this case, two senior consultants provided written agreement that the procedure was warranted. Although, there are no current laws in Trinidad and Tobago on the gestational age of viability and thus no laws on when therapeutic abortions may be permitted, our Ministry of Health, Trinidad and Tobago, circulated a document in 2016, stating a gestational age of viability of 26 weeks.13
Although the eventual treatment and outcome of this case was relatively common; this case report describes the approach to management in a setting with limited expertise and resources. It also discusses the pathophysiology of conjoined twins and outcomes in similarly encountered cases in the literature.
In conclusion, conjoined twins are a rare entity. Management is dependent on what organs are shared, the extent of sharing, and the availability of surgical and supportive resources. Detailed prenatal imaging is the key initial step in management.
Acknowledgements: The authors would like to thank the couple for permitting the use of details of the case for this report.
Ethical approval statement: Not applicable.
Financial disclosure or funding: No funding was required or sought in creating this manuscript.
Conflict of interest: The authors declare that they have no conflicts of interest.
Informed consent: Written informed consent was obtained from the patient for publication of this case according to the CARE guidelines.
Author contributions: Shane Khan was involved in patient care and responsible for the conception, drafting and editing of the manuscript. Stephen Sankar was involved in patient care and contributed to the drafting of the manuscript. Karen Sohan was involved in patient care and supervised the writing of the case report. Vishal Bachan was involved in patient care and contributed to the drafting of the manuscript. All authors approved the final submitted manuscript.
REFERENCES
- Afzal AR, Montero FJ. Conjoined Twins. [Updated 2022 Aug 8]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2022 Jan. Available from: https://www.ncbi.nlm.nih.gov/books/NBK560839/
- Kattel P. Conjoined Twins. JNMA J Nepal Med Assoc. 2018 Mar-Apr;56(211):708-710. PMID: 30381771; PMCID: PMC8997269.
- Mikolo AML, Minko JI, Kamgaing EK et al. Jumeaux conjoints thoracopages: à propos d’un cas à Libreville et revue de la littérature [Thoracopagus conjoined twins: case study conducted in Libreville and literature review]. Pan Afr Med J. 2022 Mar 16;41:220. French. doi: 10.11604/pamj.2022.41.220.32282. PMID: 35721642; PMCID: PMC9167488.
- Mian A, Gabra NI, Sharma T et al. Conjoined twins: From conception to separation, a review. Clin Anat. 2017 Apr;30(3):385-396. doi: 10.1002/ca.22839. PMID: 28195364.
- Collins RT 2nd, O’Connor MJ. The Outcomes of Surgical Separation in Thoracopagus Twins with Conjoined Hearts: An Analysis of the Literature. Pediatr Cardiol. 2021 Apr;42(4):875-882. doi: 10.1007/s00246-021-02555-8. Epub 2021 Apr 15. PMID: 33856497.
- Mathew RP, Francis S, Basti RS et al. Conjoined twins – role of imaging and recent advances. J Ultrason. 2017 Dec;17(71):259-266. doi: 10.15557/JoU.2017.0038. Epub 2017 Dec 29. PMID: 29375901; PMCID: PMC5769666.
- Wen X, Parajuly SS, Lu Q et al. Thoraco-omphalopagus conjoined twins: impact of ultrasound assessment on successful surgical separation. Clin Imaging. 2013 Jan-Feb;37(1):138-42. doi: 10.1016/j.clinimag.2012.03.004. Epub 2012 Jun 8. PMID: 23206620.
- Spencer R. Theoretical and analytical embryology of conjoined twins: part I: embryogenesis. Clin Anat. 2000;13(1):36-53. doi: 10.1002/(SICI)1098-2353(2000)13:1<36::AID-CA5>3.0.CO;2-3. PMID: 10617886.
- Waldhausen JT, Hilfiker M. Conjoined Twins. In: Ziegler MM, Azizkhan RG, Allmen D, Weber TR. Operative Pediatric Surgery, 2e. McGraw Hill; New York, NY: 2014.
- Martin HE. Chang and Eng Bunker, “The Original Siamese Twins”: living, dying, and continuing under the spectator’s gaze. J Am Cult (Malden). 2011;34(4):372-90. doi: 10.1111/j.1542-734x.2011.00787.x. PMID: 22292171.
- Başaran S, Güzel R, Keskin E et al. Parapagus (dicephalus, tetrabrachius, dipus) conjoined twins and their rehabilitation. Turk J Pediatr. 2013 Jan-Feb;55(1):99-103. PMID: 23692842.
- Medical Board of Trinidad and Tobago. Medical Board of Trinidad and Tobago Code of Ethics in the Practice of Medicine [Internet]. Trinidad and Tobago Medical Board [cited 2023 June 6] Available from: http://www.mbtt.org/CodeOfEthics_Responsibilities_to_profession.htm
- The NEOCOTT Working Group. National Palliative and Comfort Care Guidelines for Neonatal Medicine. May 2016
