An incomplete splitting of monozygotic twins results in the formation of a conjoined foetus and later the birth of conjoined twins. These types of twins are also known as Siamese twins. They share the same amniotic cavity and placenta in the mother's womb. They are mostly connected physically at the head, chest or pelvis causing some of them to share some internal organs.  40 to 60 percent of conjoined twins are stillborn, and around 35 percent survive for only one day. These conjoined twins have an overall survival rate of somewhere between 5 percent and 25 percent. 
In this research, I choose to focus on the conjoined twins who survived. There are many types of conjoined twins in which they differ by points of attachment of body parts. The common types of conjoined twins are:
Thoraco-omphalopagus: (28% of cases)  - The twins' bodies are connected from the upper chest to the lower chest. In most cases they share a heart, liver or part of the digestive system. 
Figure 1: Thoraco-omphalopagus twins
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Thoracopagus: (18.5% of cases)  - The twins' bodies are connected from the upper thorax to lower belly and they always share a heart. 
Figure 2: Thoracopagus twins
Omphalopagus: (10% of cases)  - The twins' bodies are connected at the lower chest. The heart is never involved but they often share a liver, digestive system, diaphragm and other organs. 
Figure 3: Omphalopagus twins
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Parasitic twins: (10% of cases)  - The twins are conjoined asymmetrically causing one of the twin to be smaller and depends on the larger twin for survival. 
Figure 4: Parasitic twins
Craniopagus: (6% of cases)  - Twins have separate bodies but they are connected at their skull and they can be conjoined at the back, front or the side of the head, but not on the face or the base of the skull. 
Figure 5: Craniopagus twins
It is not easy to provide care for conjoined twins as it can be very challenging. They suffer various physical and medical challenges. Twins sharing limbs or organs will be unable to move around, eat and control their heart or brain function on their own.
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Therefore, to overcome the challenges faced by conjoined twins in their daily lives, I have considered a controversial yet effective solution which is surgical separation and will be discussed further.
The procedure of the surgical separation differs depending on the type of the conjoined twins and their points of attachment. Thus, I am choosing a pair of Pygopagus conjoined twins to demonstrate the procedure involved in the surgery to separate conjoined twins.
Prior to any operative procedures, thorough evaluations including routine blood and urine analysis, coagulation screen; plain x-rays, ultra sound scans, computed tomography scans and Digital substraction angiography (DSA) are carried out. This is done to sketch out the anatomic and bone detail, demonstrate position of organs, shared viscera and limited vascular anatomy. 
Other preoperative preparations are the surgical plan, anaesthesia plan, staffing location of anesthesia and surgical equipment, patient positioning and plan for repositioning after physical separation.  Many departments of a hospital will come together and discuss and work closely so that a successful operation is ensured.
In the case of Pygopagus twins who are joined at the lower back, separation will be done over the waist of each twin.  During the surgery, vital organs and tissues are carefully dealt with. If the twins do not share any internal organs, the procedure will be much simpler whereas in the case of twins sharing internal organs, a complex procedure will be carried out and sometimes one of the twins would have to be sacrificed to save the other twin.
CUMULATIVE WORD COUNT: 626
Upon completion of separation, skin coverage has to be done. This is the main challenge in the separation surgery, especially when the area of connection part is large. Some ways of doing this is by plastic skin grafting, insertion subcutaneous skin expanders and local flap transferring. 
Figure 6: Surgical separation of a pair of Pygopagus twins
Source: Chinese Medical Journal, 2010, Vol. 123 No. 13
After surgical separation, the conjoined twins are no longer attached to each other and can live as a free individual. I strongly feel that this is the best solution for conjoined twins as it gives them the freedom to live as separate individuals. The success rate for surgical separation for conjoined twins varies depending on the body parts connected. However, the success rates have improved over the years as a result of the advancement of technology. More accurate imaging studies, better anaesthetic and operative techniques have all contributed to the improved success rate. 
Some conjoined twins who survived birth but are in critical conditions due to sharing of vital internal organs should be separated. I think this is very necessary to save at least one of the twin rather than seeing the death of both. Statistics also show that at least one twin survives separation 75 percent of the time. 
CUMULATIVE WORD COUNT: 844
The effectiveness of this procedure has been proven with the successful separation of many conjoined twins. One of which is the successful separation of a pair of male thoraco-omphalopagus twins in Korea with common liver, diaphragm, pericardium, and sternum was separated at the age of 59 days after a parasitic relationship had developed between them. 
Chart 1: Conjoined twins admitted at the Philippine General Hospital 1974-2006
Source: Pediatric Surgery International, Sep2009, Vol. 25 Issue 9, p775-780, 6p, 5 Color Photographs, 1 Chart, 1 Graph Chart; found on p776
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Figure 7: Percentage of conjoined twins surviving separation surgery
ETHICAL AND ECONOMICAL IMPLICATION
Surgical separation has raised many controversies and one of it is the rights of both twins. During the separation surgery, there is a high risk for one of the twin to be sacrificed for the benefit of the other. The ethical implication here is that each of the twins has the right to live and sacrificing one of the twins would be considered as murder. The opposite view is that and has been frequently used to support decisions in healthcare is the principle of beneficence (to do good).  In this situation, I believe that the society should take all factors into consideration before deciding on moving forward with the separation surgery.
Ethics of surgical separation also questions on who should be making the decisions for the conjoined twins. Is it the parents, doctors, hospital ethical committees, hospital administrations, the media or the law courts?  I strongly feel that it should be the parents who should be given the right on deciding the appropriate treatment and care for their children as they are in the best position to assess the future burdens and benefits of separation. The treatment they choose must be in the best interests of the child.
As Neil Campbell indicates, published data from Australia, the United Kingdom and North America show that between 30 and 80% of deaths in neonatal intensive care units follow the withholding of treatment as a result of parent/doctor decisions
Source: Campbell N (2000) The impaired fetus and the newborn. In: Dooley B, Fearnside M, Gorton M (eds) Surgery, ethics and the law. Blackwell Asia, Melbourne, pp 41-52
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Thus, with the anticipated birth of conjoined twins, the parents should meet and discuss with the paediatric team. If the twins' quality of life or if the degree of serious impairment is an issue, then the possibility of holding a surgical separation should be discussed with the parents.
Economically, surgical separation is very expensive. After comparing data from various sources, I have found that its cost varies depending on the type of conjoined twins and the complexity of the separation. The surgery alone costs upwards of US$2 million and this is for the procedure alone. The twins will also need further reconstruction and require intensive physical therapy and rehabilitation after surgery which is very important for their full recovery. 
The case of craniopagus Guatemalan sisters Maria Teresa and Maria de Jesus Quiej Alvarez, born July 25, 2001. Their August 2002 separation surgery at UCLA - not including the cost of the doctors, who donated their care, but including nursing, hospitalization, and medical expenses - will cost more than $1.5 million.
Source: World Craniofacial Foundation, 2003 (http://www.worldcf.org/)
Due to its high costs, I feel that families should seek foundations and organisations
who are willing to raise funds and contribute to the expenses of the surgery.
BENEFITS AND RISKS
Surgical separation could possibly mean that conjoined twins will be able to live as independent healthy individuals. They no longer have to be confined to the body of each other and will be able to move freely. I feel this is necessary for every individual as it is a fundamental human right. In some cases, separation is the only solution to save the lives of both twins.
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However, there are many risks revolving around this surgery. In most cases, it can be a life and death decision because it can involve sacrificing one twin's life in the hope to save the other. Hence, doctors have to convince themselves that the current quality of life is so worthless that the risky dangerous surgery is justified and should be performed. 
Survival of the twins often depends on the extent of joining and the presence or absence of associated anomalies. In the case of craniopagus twins (joined at the head), separation surgery is highly risky because it involves the brain which is a very delicate structure.  This can be seen in the case of the famous Iranian twins, Ladan Bijani and Laleh Bijani. The Bijani twins died during a marathon operation to separate them at Singapore's Raffle Hospital. 
Figure 8: Illustration on the surgery done on the Bijani twins
The greatest risk to conjoined twins before and after the separation surgery is the anaesthesia and surgical complications. The complications include formation of blood clots in the newly constructed blood vessels, intracranial bleeding, heart complications and infections. The conjoined twins are at high risk of these complications three to four days after surgery.  Therefore, it is important for careful preoperative plans to be carried out before proceeding with the surgery.
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Obstetric ultrasonography is a technique using high frequency sound waves to produce images of developing foetus inside the womb.  This method is useful to make diagnosis to check the development and detect abnormalities in the foetus. Movements such as fetal heart beat can be assessed and measurements can be made accurately on the images displayed on the screen. 
Figure 9: Transducer (probe) on the abdomen
Diagnosis of conjoined twins is possible at 10 - 12 weeks of gestation but it is not easy to determine which body parts are involved until 20 weeks of gestation.  If the foetus is conjoined, nonseparated external skin contour will be demonstrated on the ultrasound image. Besides that, the body parts of the twins will be on the same sonar plane and there will be no change in the relative position of the twins in successive scans. [2, 3]
Figure 10: 4D ultrasound image of a pair of conjoined twins in its foetal stage
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I feel that through this diagnosis, parents can make decisions early in the pregnancy. Since it is the parents who will have to provide childcare and seek treatments for the conjoined twins after their birth, they should be given the rights to decide on the termination of the pregnancy. I also feel that it is better for the mother carrying the conjoined twins to opt for abortion if they are not able to cater to the needs of the twins once they are born. This will save the twins from going through a hard life.
Since separation surgery is highly risky and fatal in some cases, parents can choose to provide the conjoined twins with comfort care. The lives of conjoined twins if not separated could be a tough one both emotionally and physically. It's not easy to be stuck with another person for the rest of your life worse still having to go through daily routines together. Hence, I feel parents should be there to provide them with the care they need. They need to be constantly treated like a normal human being so that they won't feel alienated. Some conjoined twins do not have a long life span due to the sharing of vital organs. These twins are better off given comfort care than going through surgical separation. They should make the most of the time they have left on Earth.
MayoClinic.com is a website designed to provide health information, self-improvement and disease management tools. I find this website a very reliable source because it is produced by a team of Web professionals and medical experts. This website complies with the HONcode standard for trustworthy health information. It also won many awards and has been listed in the 2010 "Time" Magazine for Top 50 Web sites. I retrieved the facts on conjoined twins as stated on page 1 from http://www.mayoclinic.com/health/conjoined-twins/DS00869.
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My next source that I have evaluated is a non-web source. It is a journal by Rosalie O MainousÂ (2002) titled Conjoined twins: Whose best interest should prevail? An argument for separation.Â Pediatric Nursing,Â 28(5),Â 525-9.Â from ProQuest Education Journals. The author of this book, Rosalie O Mainous is an Associate Dean for Graduate Programs and Research in the University of Louisville. I believe she is a reliable writer because of her knowledge and expertise in the medical field. Her qualifications are PhD, ARNP, NNP-BC. Her teaching area in the University of Louisville is neonatal. She has done many researches and her particular interests are high risk neonates/VLBW and neonatal pain. I retrieved information on the ethical implication of surgical separation of conjoined twins from her journal.
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